Agilent Technologies Ventilation Hood Agilent 86120C User Manual

Agilent 86120C

Multi-Wavelength Meter

User’s Guide

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The Agilent 86120C—At a Glance

The Agilent 86120C Multi- Wavelength Meter measures the wavelength

and optical power of laser light in the 1270–1650 wavelength range.

Because the Agilent 86120C simultaneously measures multiple laser

lines, you can characterize wavelength- division- multiplexed (WDM)

systems and the multiple lines of Fabry- Perot lasers.

NOTE

The front-panel OPTICAL INPUT connector uses a single-mode input fiber.

C A U T IO N

For Option 022 instruments, the front-panel OPTICAL INPUT connector is an

angled physical contact interface.

Characterize laser lines easily

With the Agilent 86120C you can quickly and easily measure any of

the following parameters:

• Measure up to 200 laser lines simultaneously

• Wavelengths and powers

• Average wavelength

• Total optical power

• Laser line separation

• Laser drift (wavelength and power)

• Signal- to-noise ratios

• Fabry- Perot lasers

iii

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The Agilent 86120C—At a Glance

In addition to these measurements, a “p ower bar” is disp layed that

shows power changes like a traditional analog meter. You can see the

p ower bar shown in the following figure of the Agilent 86120C’s dis-

play.

C A U T IO N

The input circuitry of the Agilent 86120C can be damaged when total input

power levels exceed +18 dBm. To prevent input damage, this specified level

must not be exceeded.

Print measurement results

You can get hardcopy results of your measurements by connecting a

printer to the rear- panel PARALLEL PRINTER PORT connector.

Program the instrument for automatic measurements

The Agilent 86120C offers an extensive set of GPIB programming com-

mands. These commands allow you to p erform automated measure-

ments on manufacturing production lines and remote sites. Chapter 3,

“Programming” and Chapter 4, “Programming Commands” provide all

the information you’ll need to know in order to p rogram the

Agilent 86120C.

Display wavelengths as if measured in vacuum or standard air

Although all measurements are made in air, disp layed results are cor-

rected for air disp ersion to accurately show wavelength values in vac-

uum or in “standard air.” To ensure accurate wavelength

measurements, make sure that you enter the elevation from which you

will be making measurements as described in Chapter 1, “Getting

Started”.

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The Agilent 86120C—At a Glance

Measurement accuracy—it’s up to you!

Fiber-optic connectors are easily damaged when connected to dirty or damaged

cables and accessories. The Agilent 86120C’s front-panel INPUT connector is no

exception. When you use improper cleaning and handling techniques, you risk

expensive instrument repairs, damaged cables, and compromised measurements.

Before you connect any fiber-optic cable to the Agilent 86120C, refer to “Cleaning

Connections for Accurate Measurements” on page 2-40.

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General Safety Considerations

This p roduct has been designed and tested in accordance with IEC

61010- 1, and has been sup p lied in a safe condition. The instruction

documentation contains information and warnings which must be fol-

lowed by the user to ensure safe op eration and to maintain the p rod-

uct in a safe condition.

Laser Classification: This product is classified according to

IEC 60825- 1.

There is no output laser aperture

The Agilent 86120C does not have an output laser aperture. However, light less

than 1 nW escapes out of the front-panel OPTICAL INPUT connector. Operator

maintenance or precautions are not necessary to maintain safety. No controls,

adjustments, or performance of procedures result in hazardous radiation expo-

sure.

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General Safety Considerations

WA R N IN G

If this instrument is not used as specified, the protection provided by

the equipment could be impaired. This instrument must be used in a

normal condition (in which all means for protection are intact) only.

WA R N IN G

No operator serviceable parts inside. Refer servicing to qualified

personnel. To prevent electrical shock, do not remove covers.

To prevent electrical shock, disconnect the Agilent 86120C from mains

before cleaning. Use a dry cloth or one slightly dampened with water

to clean the external case parts. Do not attempt to clean internally.

WA R N IN G

This is a Safety Class 1 product (provided with protective earth). The

mains plug shall only be inserted in a socket outlet provided with a

protective earth contact. Any interruption of the protective conductor

inside or outside of the product is likely to make the product dangerous.

Intentional interruption is prohibited.

WA R N IN G

For continued protection against fire hazard, replace line fuse only with

same type and ratings, (type F 6.3A/250V IEC 60127 type 5x20mm). The

use of other fuses or materials is prohibited. Verify that the value of the

line-voltage fuse is correct.

vii

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General Safety Considerations

C A U T IO N

This product complies with Overvoltage Category II and Pollution Degree 2.

VENTILATION REQUIREMENTS: When installing the product in a cabinet, the

convection into and out of the product must not be restricted. The ambient

temperature (outside the cabinet) must be less than the maximum operating

temperature of the product by 4°C for every 100 watts dissipated in the cabinet.

If the total power dissipated in the cabinet is greater than 800 watts, then forced

convection must be used.

C A U T IO N

Always use the three-prong ac power cord supplied with this instrument. Failure

to ensure adequate earth grounding by not using this cord may cause

instrument damage.

Do not connect ac power until you have verified the line voltage is correct as

described in “Line Power Requirements” on page 1-5. Damage to the equipment

could result.

This instrument has autoranging line voltage input. Be sure the supply voltage

is within the specified range.

viii

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Contents

The Agilent 86120C—At a Glance iii

General Safety Considerations vi

1 Getting Started

Step 1. Inspect the Shipment 4

Step 2. Connect the Line-Power Cable 5

Step 3. Connect a Printer 6

Step 4. Turn on the Agilent 86120C 7

Step 5. Enter Your Elevation 8

Step 6. Select Medium for Wavelength Values 9

Step 7. Turn Off Wavelength Limiting 10

Returning the Instrument for Service 11

2 Making Measurements

Measuring Wavelength and Power 3

Changing the Units and Measurement Rate 12

Defining Laser-Line Peaks 15

Measuring Laser Separation 18

Measuring Laser Drift 22

Measuring Signal-to-Noise Ratios 25

Measuring Signal-to-Noise Ratios with Averaging 29

Measuring Fabry-Perot (FP) Lasers 31

Measuring Modulated Lasers 34

Measuring Total Power Greater than 10 dBm 36

Calibrating Measurements 37

Printing Measurement Results 39

Cleaning Connections for Accurate Measurements 40

3 Programming

Addressing and Initializing the Instrument 3

Making Measurements 5

Monitoring the Instrument 16

Reviewing SCPI Syntax Rules 23

Example Programs 28

Lists of Commands 43

Contents-1

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Contents

4 Programming Commands

Common Commands 3

Measurement Instructions 15

CALCulate1 Subsystem 25

CALCulate2 Subsystem 31

CALCulate3 Subsystem 44

CONFigure Measurement Instruction 74

DISPlay Subsystem 75

FETCh Measurement Instruction 79

HCOPy Subsystem 80

MEASure Measurement Instruction 81

READ Measurement Instruction 82

SENSe Subsystem 83

STATus Subsystem 90

SYSTem Subsystem 97

TRIGger Subsystem 103

UNIT Subsystem 107

5 Performance Tests

Test 1. Absolute Wavelength Accuracy 3

Test 2. Sensitivity 4

Test 3. Polarization Dependence 5

Test 4. Optical Input Return Loss 6

Test 5. Amplitude Accuracy and Linearity 9

6 Specifications and Regulatory Information

Definition of Terms 3

Specifications—NORMAL Update Mode 5

Specifications—FAST Update Mode 8

Operating Specifications 11

Laser Safety Information 12

Compliance with Canadian EMC Requirements 13

Declaration of Conformity 14

Product Overview 15

7 Reference

Instrument Preset Conditions 2

Contents-2

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Contents

Menu Maps 4

Error Messages 11

Front-Panel Fiber-Optic Adapters 17

Power Cords 18

Agilent Technologies Service Offices 18

Contents-3

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Step 1. Inspect the Shipment 1- 4

Step 2. Connect the Line- Power Cable 1- 5

Step 3. Connect a Printer 1- 6

Step 4. Turn on the Agilent 86120C 1- 7

Step 5. Enter Your Elevation 1- 8

Step 6. Select Medium for Wavelength Values 1- 9

Step 7. Turn Off Wavelength Limiting 1- 10

Returning the Instrument for Service 1- 11

Getting Started

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Getting Started

The instructions in this chap ter show you how to install your

Agilent 86120C. You should be able to finish these procedures in about

ten to twenty minutes. After you’ve comp leted this chap ter, continue

with Chapter 2, “Making Measurements”.

Refer to Chapter 6, “Specifications and Regulatory Information” for

information on operating conditions such as temperature.

If you should ever need to clean the cabinet, use a damp cloth only.

C A U T IO N

This product has autoranging line voltage input. Be sure the supply voltage is

within the specified range.

The front panel LINE switch disconnects the mains circuits from the mains

supply after the EMC filters and before other parts of the instrument.

Install the instrument so that the LINE switch is readily identifiable and is easily

reached by the operator. The LINE switch or the detachable power cord is the

instrument disconnecting device. It disconnects the mains circuits from the

mains supply before other parts of the instrument. Alternately, an externally

installed switch or circuit breaker (which is really identifiable and is easily

reached by the operator) may be used as a disconnecting device.

C A U T IO N

Install the instrument according to the enclosure protection provided. This

instrument does not protect against the ingress of water. This instrument

protects against finger access to hazardous parts within the enclosure.

1-2

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Getting Started

Measurement accuracy—it’s up to you!

Fiber-optic connectors are easily damaged when connected to dirty or damaged

cables and accessories. The Agilent 86120C’s front-panel INPUT connector is no

exception. When you use improper cleaning and handling techniques, you risk

expensive instrument repairs, damaged cables, and compromised measurements.

Before you connect any fiber-optic cable to the Agilent 86120C, refer to “Cleaning

Connections for Accurate Measurements” on page 2-40.

1-3

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Getting Started

Step 1. Inspect the Shipment

1 Verify that all system components ordered have arrived by comparing

the shipping forms to the original purchase order. Inspect all shipping

containers.

If your shipment is damaged or incomplete, save the packing materials and notify

both the shipping carrier and the nearest Agilent Technologies sales and service

office. Agilent Technologies will arrange for repair or replacement of damaged or

incomplete shipments without waiting for a settlement from the transportation

company. Notify the Agilent Technologies customer engineer of any problems.

2 Make sure that the serial number and options listed on the instrument’s

rear- p anel label match the serial number and op tions listed on the

shipping document. The following figure is an example of the rear- panel

serial number label:

1-4

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Getting Started

Step 2. Connect the Line-Power Cable

Step 2. Connect the Line- Power Cable

WA R N IN G

This is a Safety Class I Product (provided with protective earth). The

mains plug shall only be inserted in a socket outlet provided with a

protective earth contact. Any interruption of the protective conductor

inside or outside of the instrument is likely to make the instrument

dangerous. Intentional interruption is prohibited.

C A U T IO N

Always use the three-prong AC power cord supplied with this instrument.

Failure to ensure adequate earth grounding by not using this cord may cause

instrument damage.

C A U T IO N

Do not connect ac power until you have verified the line voltage is correct as

described in the following paragraphs. Damage to the equipment could result.

This instrument has autoranging line voltage input. Be sure the supply voltage

is within the specified range.

1 Verify that the line p ower meets the requirements shown in the

following table.

Line Power Requirements

Power:

max. 70 W

Voltage:

Frequency

max: 110 / 115 / 230 / 240 V~

50 / 60 Hz

2 Connect the line- p ower cord to the instrument’s rear- p anel connector.

1-5

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Getting Started

Step 3. Connect a Printer

3 Connect the other end of the line- p ower cord to the p ower recep tacle.

Various power cables are available to connect the Agilent 86120C to ac

p ower outlets unique to sp ecific geograp hic areas. The cable ap p rop ri-

ate for the area to which the Agilent 86120C is originally shipped is

included with the unit. The cable shipped with the instrument also has

a right- angle connector so that the Agilent 86120C can be used while

sitting on its rear feet. You can order additional ac p ower cables for

use in different geographic areas. Refer to “Power Cords” on

page 7- 18.

Step 3. Connect a Printer

The Agilent 86120C can p rint hardcop ies of measurement results on a

p rinter. The outp ut is ASCII text. If you don’t have a p rinter, continue

with “Step 4. Turn on the Agilent 86120C” on p age 1- 7 .

1 Using a standard parallel printer cable, connect the printer to the

Agilent 86120C’s rear- panel PARALLEL PRINTER PORT connector.

1-6

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Getting Started

Step 4. Turn on the Agilent 86120C

1 Press the front- panel LINE key. After ap proximately 20 seconds, the

display should look similar to the figure below.

The front- panel LINE switch disconnects the mains circuits from the

mains supply after the EMC filters and before other parts of the instru-

ment.

2 If the Agilent 86120C fails to turn on p rop erly, consider the following

possibilities:

• Is the line fuse good?

• Does the line socket have power?

• Is it p lugged into the p rop er ac p ower source?

If the instrument still fails, return it to Agilent Technologies for repair.

Refer to “Returning the Instrument for Service” on p age 1- 11

Instrument firmware version

When the instrument is first turned on, the display briefly shows the instrument’s

firmware version number. In the unlikely event that you have a problem with the

Agilent 86120C, you may need to indicate this number when communicating with

Agilent Technologies.

1-7

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Getting Started

Step 5. Enter Your Elevation

In order for your Agilent 86120C to accurately measure wavelengths

and meet its p ublished sp ecifications, you must enter the elevation

where you will be performing your measurements.

1 Press the Setup key.

2 Press the MORE softkey.

3 Press the CAL softkey.

4 Press ELEV.

5 Use the

and

softkeys to enter the elevation in meters. Entries

jump in 500 meter steps from 0 m to 5000 m.

The elevation value selected with the softkeys must be within 250

meters of the actual elevation.

6 Press RETURN to comp lete the entry.

Converting feet to meters

If you know your elevation in feet, you can convert this value to meters by using

the following equation:

3,281

------------

m =

1-8

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Getting Started

Step 6. Select Medium for Wavelength Values

Because wavelength varies with the material that the light p asses

through, the Agilent 86120C offers wavelength measurements in two

mediums: vacuum and standard air.

1 Press the Setup key.

2 Press the MORE softkey.

3 Press the CAL softkey.

4 Make the following selection:

• Press VACUUM for wavelength readings in a vacuum.

• Press STD AIR for wavelength readings in standard air.

5 Press RETURN to comp lete the entry.

Definition of standard air

Standard air is defined to have the following characteristics:

Barometric pressure: 1013 mbar

Temperature:

Relative humidity: 0%

15°C

1-9

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Getting Started

Step 7. Turn Off Wavelength Limiting

The instrument’s Preset key sets the entire Agilent 86120C wavelength

range of 1270–1650 nm. If a user- defined wavelength range limit was

set using WL LIM, the following procedure will ensure that responses

across the full wavelength are measured by returning the instrument to

its preset state.

1 Press the Setup key.

2 Press the WL LIM softkey.

3 Press LIM OFF to remove the limits on wavelength range.

1-10

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Getting Started

Returning the Instrument for Service

The instructions in this section show you how to p rop erly return the

instrument for rep air or calibration. Always call the Agilent Technolo-

gies Instrument Support Center first to initiate service before returning

your instrument to a service office. This ensures that the rep air (or

calibration) can be p rop erly tracked and that your instrument will be

returned to you as quickly as possible. Call this number regardless of

where you are located. Refer to “Agilent Technologies Service Offices”

on page 7- 18 for a list of service offices.

Agilent Technologies Instrument Support Center +1 (877) 447 7278

If the instrument is still under warranty or is covered by an Agilent

Technologies maintenance contract, it will be repaired under the terms

of the warranty or contract (the warranty is at the front of this man-

ual). If the instrument is no longer under warranty or is not covered

by an Agilent Technologies maintenance plan, Agilent Technologies will

notify you of the cost of the repair after examining the unit.

When an instrument is returned to a Agilent Technologies service

office for servicing, it must be adequately p ackaged and have a com-

plete description of the failure symptoms attached. When describing

the failure, please be as specific as possible about the nature of the

problem. Include copies of additional failure information (such as the

instrument failure settings, data related to instrument failure, and

error messages) along with the instrument being returned.

1-11

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Getting Started

Returning the Instrument for Service

Preparing the instrument for shipping

1 Write a complete description of the failure and attach it to the

instrument. Include any specific performance details related to the

p roblem. The following information should be returned with the

instrument.

• Type of service required.

• Date instrument was returned for repair.

• Description of the problem:

•

Whether problem is constant or intermittent.

Whether instrument is temperature-sensitive.

Whether instrument is vibration-sensitive.

Instrument settings required to reproduce the problem.

Performance data.

• Company name and return address.

• Name and p hone number of technical contact p erson.

• Model number of returned instrument.

• Full serial number of returned instrument.

• List of any accessories returned with instrument.

2 Cover all front or rear- panel connectors that were originally covered

when you first received the instrument.

C A U T IO N

Cover electrical connectors to protect sensitive components from electrostatic

damage. Cover optical connectors to protect them from damage due to physical

contact or dust.

Instrument damage can result from using packaging materials other than the

original materials. Never use styrene pellets as packaging material. They do not

adequately cushion the instrument or prevent it from shifting in the carton. They

may also cause instrument damage by generating static electricity.

1-12

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Getting Started

Returning the Instrument for Service

3 Pack the instrument in the original ship p ing containers. Original

materials are available through any Agilent Technologies office. Or, use

the following guidelines:

• Wrap the instrument in antistatic plastic to reduce the possibility of

damage caused by electrostatic discharge.

• For instruments weighing less than 54 kg (120 lb), use a double-

walled, corrugated cardboard carton of 159 kg (350 lb) test strength.

• The carton must be large enough to allow ap p roximately 7 cm

(3 inches) on all sides of the instrument for p acking material, and

strong enough to accommodate the weight of the instrument.

• Surround the equipment with approximately 7 cm (3 inches) of pack-

ing material, to protect the instrument and prevent it from moving

in the carton. If packing foam is not available, the best alternative is

S.D- 240 Air Cap™ from Sealed Air Corporation (Commerce, Califor-

nia 90001). Air Cap looks like a plastic sheet filled with air bubbles.

Use the pink (antistatic) Air Cap™ to reduce static electricity. Wrap-

p ing the instrument several times in this material will p rotect the

instrument and p revent it from moving in the carton.

4 Seal the carton with strong nylon adhesive tap e.

5 Mark the carton “FRAGILE, HANDLE WITH CARE”.

6 Retain copies of all shipping papers.

1-13

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Getting Started

Returning the Instrument for Service

1-14

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Getting Started

Returning the Instrument for Service

1-15

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Measuring Wavelength and Power 2- 3

Peak WL mode 2-4

List by WL or Power modes 2-6

Total power and average wavelength 2-7

Limiting the wavelength measurement range 2-8

Measuring broadband devices and chirped lasers 2-9

Graphical display of optical power spectrum 2-10

Instrument states 2-11

Power bar 2-11

Changing the Units and Measurement Rate 2- 12

Displayed units 2-12

Measurement rate 2-13

Continuous or single measurements 2-14

Defining Laser-Line Peaks 2- 15

Measuring Laser Separation 2- 18

Channel separation 2-19

Measuring flatness 2-21

Measuring Laser Drift 2- 22

Measuring Signal- to- Noise Ratios 2- 25

Measuring Signal- to- Noise Ratios with Averaging 2- 29

Measuring Fabry- Perot (FP) Lasers 2- 31

Measuring Modulated Lasers 2- 34

Measuring Total Power Greater than 10 dBm 2- 36

Calibrating Measurements 2- 37

Printing Measurement Results 2- 39

Cleaning Connections for Accurate Measurements 2- 40

Making Measurements

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Making Measurements

In this chapter, you’ll learn how to make a variety of fast, accurate

measurements. As you p erform these measurements, keep in mind the

following points:

• 1270–1650 maximum input wavelength range

• +10 dBm maximum total displayed input power

• Laser linewidths assumed to be less than 5 GHz

• If you change the elevation where you will be using your

Agilent 86120C, refer to “Calibrating Measurements” on page 2- 37.

• Press the green Preset key to return the Agilent 86120C to its default

state.

C A U T IO N

Do not exceed +18 dBm source power. The Agilent 86120C’s input circuitry can

be damaged when total input power exceeds 18 dBm. You can measure power

levels that are greater by adding attenuation and entering a power offset as

described in “To measure total power exceeding 10 dBm” on page 2-36.

2-2

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Making Measurements

Measuring Wavelength and Power

This section gives you step - by- step instructions for measuring p eak

wavelength, average wavelength, peak power, and total input power.

There are three display modes:

• Peak wavelength

• List-by- wavelength or p ower

• Average wavelength and total power

If the measured amplitudes are low, clean the front- panel OPTICAL

INPUT connector.

This section includes:

Peak WL mode 2- 4

List by WL or Power modes 2- 6

Total p ower and average wavelength 2- 7

Limiting the wavelength measurement range 2- 8

Measuring broadband devices and chirped lasers 2- 9

Graphical display of optical power spectrum 2- 10

Instrument states 2- 11

Power bar 2- 11

2-3

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Making Measurements

Measuring Wavelength and Power

Peak WL mode

When Peak WL is pressed, the display shows the largest amplitude line

in the sp ectrum. The word PEAKis shown on the screen. If multip le

laser lines are present at the input, the number of lines located will be

shown along the right side of the screen. In peak wavelength mode, the

Agilent 86120C can measure up to 200 laser lines simultaneously.

Figure 2-1. Display after “Peak WL” key pressed

In addition to the digital readouts, there is a p ower bar. It provides a

convenient analog “meter movement” for tuning laser p ower.

Although the Peak WL mode shows one signal at a time, softkeys are

provided that allow you to scroll through and display all the measured

laser lines. You can scroll through the list according to the wave-

lengths or powers measured.

To display peak wavelength and power

1 Connect the fiber- optic cable to the front- panel OPTICAL INPUT

connector.

2 To disp lay the p eak wavelength and p ower, do one of the following:

• Press the green Preset key.

• Press Peak WL.

2-4

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Making Measurements

Measuring Wavelength and Power

3 To move the cursor to view other signals, p ress:

• PREV WL to select next (p revious) shorter wavelength.

• NEXT WL to select next longer wavelength.

• PEAK to signal with greatest p ower.

• PREV PK to select next lower p ower signal.

• NEXT PK to select next higher p ower signal.

2-5

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Making Measurements

Measuring Wavelength and Power

List by WL or Power modes

In the list- by- wavelength or list- by- power modes, the measurements of

five laser lines can be disp layed at any one time. Use the

and

softkeys to move the cursor through the list of signals; the list can

contain up to 200 entries. Press the SELECT key, and the display

changes to p eak wavelength mode with the signal at the cursor dis-

played.

Annotation in the upper right corner of the display indicates whether

the signals are ordered according to wavelength (BY WL) or power ( BY

PWR). The cursor shows the currently selected laser line. As you scroll

through the resp onses, the current p osition of the selection cursor is

shown along the screen’s right side.

Figure 2-2. Display after “List by WL” key pressed

Also notice that p ower bars grap hically show the relative p ower levels

between laser lines.

To display multiple laser lines

1 Connect the fiber- optic cable to the front- panel OPTICAL INPUT

connector.

2 Press the green Preset key.

3 Press List by WL to display the laser lines from the shortest wavelength

to the longest wavelength.

4 Press List by Power to display the laser lines in order of decreasing

amplitudes.

2-6

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Making Measurements

Measuring Wavelength and Power

Total power and average wavelength

In the third available disp lay mode, the Agilent 86120C disp lays the

average wavelength as shown in the following figure. The disp layed

power level is the total input power to the instrument. It is the sum of

the powers of each laser line; it is not a measure of the average power

level of the laser lines.

The following equation shows how individual wavelengths of laser lines

are summed together to obtain the average wavelength value:

P λ

i = 1

--------------------

avg

i = 1

where,

n is the number of laser lines included in the average.

P_iis the peak power of an individual laser line. Power units are in Watts (linear).

2-7

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Making Measurements

Measuring Wavelength and Power

The following equation shows how individual p owers of laser lines are

summed together to obtain the total power value:

total

i = 1

where,

n is the number of laser lines included in the measurement.

P_iis the peak power of an individual laser line. Power units are in Watts (linear).

To display average wavelength and total power

• Press the Avg WL key.

Limiting the wavelength measurement range

The wavelength range of measurement can be limited with the wave-

length limit function. Both start and stop wavelengths can be chosen.

The units of wavelength start and stop are the same as the currently

selected wavelength units. If wavelength units are later changed, the

start and stop wavelength units will change accordingly. Note that a

start wavelength limit in nm will become a stop wavelength limit if

THz or cm^-1is chosen. See “To change the units of measure” on

page 2- 12.

The graphical display uses the start and stop wavelength values to plot

the power spectrum, whether the wavelength limit function is on or

off.

Preset turns wavelength limiting on. Only responses that are within the

boundaries of the chosen start and stop wavelength limits are mea-

sured. This includes Peak WL, List by WL, and List by Power modes.

To limit the wavelength range

1 Press the Setup key.

2 Press the WL LIM softkey.

3 Press the STARTWL softkey to adjust the start wavelength value.

4 Press the STOP WL softkey to adjust the stop wavelength value.

2-8

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Making Measurements

Measuring Wavelength and Power

Measuring broadband devices and chirped lasers

When first turned on (or the green Preset key is p ressed), the

Agilent 86120C is configured to measure narrowband devices such as

DFB lasers and modes of FP lasers. If you plan to measure broadband

devices such as LEDs, op tical filters, and chirped lasers, use the

Setup

menu first to reconfigure the instrument. When broadband devices are

selected, the display shows the BROAD annotation on the screen.

The measurement algorithm for broadband devices determines the

wavelength based upon the center- of- mass of the power spectrum. The

peak excursion function is used to determine the value of the integra-

tion limits. Care must be taken to ensure that the integration limits

are above any noise. This is especially true when measuring devices

with slop ing noise floors, like an EDFA amp lifier. For more informa-

tion on peak excursion, refer to “Defining Laser- Line Peaks” on p age

2- 15.

Instrument specifications apply when the Agilent 86120C is configured

to measure narrowband devices. Specifications do not apply when the

instrument is configured to measure wideband devices.

To measure broadband devices

1 Press the Setup key.

2 Press MORE twice, and then the DEVICE softkey.

3 Press the BROAD softkey.

To return to measuring narrowband devices, p ress NARROW.

2-9

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Making Measurements

Measuring Wavelength and Power

Graphical display of optical power spectrum

A graphical display of optical power versus wavelength is shown from

the start wavelength value to the stop wavelength value. The start

wavelength value is shown in the up p er- left corner of the grap hical

disp lay, and the stop wavelength value is shown in the up p er- right

corner of the grap hical disp lay. The p ower scale is a fixed dB scale,

with +10 dBm at the display top and –53 dBm at the display bottom.

The p ower scale is not affected by the Power Offset value. In most

cases, the noise floor will be visible if the total inp ut power is greater

than about –5 dBm.

The Agilent 86120C graphical display.

The Peak Threshold value is disp layed as a dotted line. All p eaks

above this dotted line are displayed in the List by Wavelength and List

by Power modes. All p eaks below this line are not disp layed. Adjust

the Peak Threshold value with the Setup key, and the THRSHLD softkey.

The wavelength limit start and stop wavelength values are used for the

graphical display even if the wavelength limit function is off.

The graphical display cannot be printed.

To see the graphical display

1 Press the List by WL or List by Power key.

2 Press the GRAPH softkey.

3 To exit the graphical display, press any softkey.

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Making Measurements

Measuring Wavelength and Power

Instrument states

Four different instrument states can be saved and recalled at a later

time. The actual instrument conditions that are saved are identical to

those saved from the p revious state after p ower is turned on. These

conditions are shown in Table 5- 22onp age 7- 2 . If drift measurements

or an ap p lication (such as signal-to- noise) is on when an instrument

state is saved, it is off when that state is recalled.

To save an instrument state

1 Press the Setup key.

2 Press the SAV/RCL softkey.

3 Press the SAVE softkey.

4 Press one of the four SAVE softkeys to save the instrument state.

To recall an instrument state

1 Press the Setup key.

2 Press the SAV/RCL softkey.

3 Press the RECALL softkey.

4 Press one of the four RCL softkeys to recall an instrument state.

Power bar

To control the power bar

1 Press the Setup key.

2 Press MORE twice, and then PWR BAR.

3 Press BAR ON to disp lay the p ower bar, and p ress BAR OFF to hide the

power bar display.

2-11

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Making Measurements

Changing the Units and Measurement Rate

This section includes step - by-step instructions for changing the units

and measurement rate.

This section includes:

Displayed units 2- 12

Measurement rate 2- 13

Continuous or single measurements 2- 14

Displayed units

As described below, it’s easy to change the wavelength and amp litude

units. You can choose between the following units:

Table 2-1. Available Units

Wavelength (Frequency)

Power

dBm

cm^–1

THz

µW

To change the units of measure

1 Press Setup.

2 Press the MORE softkey.

3 Press the UNITS softkey.

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Making Measurements

Changing the Units and Measurement Rate

4 Press WL and select one of the following units. Then, press RETURN to

complete your selection:

• NM for nanometers

• THZ for Tera Hertz

• CM ^–1for wave number

5 Press POWER and select one of the following units:

• DBM for decibels relative to a milliwatt

• MW for milliwatts

• UW for microwatts

Measurement rate

Under normal op eration, the Agilent 86120C makes a measurement

and disp lays the results about once every second. It is in this normal

update mode that maximum accuracy and wavelength resolution are

achieved. However, should a faster up date be desired, for examp le

when real- time feedback is required to tune a laser to its designated

channel, the Agilent 86120C can be set to up date ap p roximately two

times p er second. This reduces both wavelength resolution and accu-

racy but can be beneficial in some ap p lications.

The instrument resolution in NORMAL update mode is 7 GHz (0.06 nm

at 1550 nm). This resolution is useful when measuring closely sp aced

laser lines carrying data at up to 5 Gb/s rates.

The instrument resolution in FAST update mode is 14 GHz (0.12 nm at

1550 nm). This resolution is useful when measuring laser lines carry-

ing data at up to 10 Gb/s rates.

NOTE

When measuring laser lines carrying data at 10 Gb/s in NORMAL update mode,

the instrument resolution is less than the modulation bandwidth of the laser lines.

In this case, the displayed power of the laser lines will be less than the actual

power by approximately 1 dB. This power offset can be calculated by comparing

the displayed power to that measured by a power meter. Then, the power offset

can be entered, by pressing Setup, MORE, CAL, PWR OFS, to display the correct

power.

2-13

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Making Measurements

Changing the Units and Measurement Rate

To change the measurement speed

1 Press the Setup key.

2 Press the MORE softkey.

3 Press the UPDATE softkey.

4 Select either NORMAL or FAST.

Continuous or single measurements

The Agilent 86120C continuously measures the input spectrum at the

front- panel OPTICAL INPUT connector. Whenever measurements are

being acquired, an asterisk (*) is displayed in the display’s upper- right

corner. When you switch between normal and fast up date modes, the

rate that the asterisk blinks changes.

You can specify that the instrument perform a measurement only when

the front-panel Single key is pressed. This is the single- acquisition

measurement mode, and it is useful for capturing and preserving data.

After cap turing the data, you can disp lay it using many of the p roce-

dures included in this chap ter. You can return to continuous measure-

ment mode at any time by p ressing the

Cont key.

To select single measurement acquisition

• Press the Single key.

2-14

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Making Measurements

Defining Laser-Line Peaks

The Agilent 86120C uses two rules to identify valid laser- line peaks.

Understanding these rules is essential to getting the most from your

measurements. For example, these rules allow you to “hide” AM mod-

ulation sidebands or locate laser lines with small amplitudes.

In order to identify a laser line, the laser- line must meet both of the

following rules:

• Power must be greater than the power established by the peak threshold

limit

• Power must rise and then fall by at least the peak excursion value

In addition, the inp ut wavelength range can be limited as described in

this section.

Peak threshold

limit

The peak threshold limit is set by subtracting the peak threshold value

from the p ower of the largest laser line. So, if the largest laser line is

2 dBm and the peak threshold value is 10 dB, the peak threshold limit

is –8 dBm (–8 dBm = 2 dBm – 10 dB ) . You can set the peak threshold

value between 0 to 40 dB.

The peak threshold’s default value is 10 dB. This ensures that any

modulated signals being measured are not confused with their AM

sidebands. For unmodulated lasers, or Fabry- Perot lasers, it may be

desirable to increase this threshold to look for responses that are more

than 10 dB from the p eak.

Peak threshold can be used to suppress spurious signals. For example,

a laser that is amplitude modulated in the audio frequency range can

cause spurious wavelengths to be displayed below and above the cor-

rect wavelength. The p ower of these sp urious wavelengths is below

that of the correct wavelength. These sp urious signals can be elimi-

nated by decreasing Peak threshold from its Preset value.

2-15

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Making Measurements

Defining Laser-Line Peaks

Peak excursion

The peak excursion defines the rise and fall in amplitude that must

take p lace in order for a laser line to be recognized. The rise and fall

can be out of the noise, or in the case of two closely sp aced signals,

out of the filter skirts of the adjacent signal. The p eak excursion’s

default value is 15 dB. Any laser line that rises by 15 dB and then

falls by 15 dB passes the rule. You can set the peak excursion value

from 1 to 30 dB.

Examples of valid In the following figure, three laser lines are identified: resp onses 1, 3

and invalid signals and 4. Resp onse 2 is not identified because it is below the p eak

threshold. The portion of each signal that is within the peak excursion

limits is shown in bold lines.

Because of the peak excursion rule, responses 4 and 5 are identified

as one laser line—the minimum p oint between 4 and 5 does not drop

to the p eak excursion limit. This resp onse has the highest p ower

shown, which is peak 4.

Whenever the peak threshold limit or peak excursion value is changed,

the new limits are applied to the current displayed measurements even

if the instrument is in the Single measurement mode.

To define laser- line peaks

1 Press the Setup key.

2 Press the THRSHLD softkey.

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Making Measurements

Defining Laser-Line Peaks

3 Press PX EXC, and enter the peak excursion value. Use the

softkey

to select the digit that requires editing. Use the

change the value.

and

softkeys to

The peak excursion value can range from 1 to 30 dB. The default value

is 15 dB.

4 Press RETURN.

5 Press PK THLD and then enter the peak threshold value.

The peak threshold value can range from 0 to 40 dB. Setting this value

to 0 dB ensures that only the peak wavelength is identified. The default

value is 10 dB.

Pressing the green PRESET key changes the peak excursion and peak

threshold values to their default settings. It also turns wavelength

range limiting on. Turning the Agilent 86120C’s power off and then on

does not change these settings.

If too many lines are identified

If the following message is displayed, too many laser lines have been identified:

E15 MAX NUMBER OF SIGNALS FOUND

The maximum number of laser lines that the instrument can measure is 200. If

this message appears, decrease the peak threshold value, increase the peak

excursion value, or decrease the wavelength range of operation with the WL

LIM ....START WL and STOP WL functions.

2-17

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Making Measurements

Measuring Laser Separation

It is often imp ortant to measure the wavelength and p ower sep aration

between multiple laser lines. This is especially true in wavelength-divi-

sion- multiplexed (WDM) systems where channel spacing must be

adhered to. The Agilent 86120C can disp lay the wavelength and amp li-

tude of any laser line relative to another. In fact, the following types of

relative measurements can be made compared to the reference:

• Relative wavelength, absolute power

• Relative power, absolute wavelength

• Relative wavelength and p ower

This section includes:

Channel separation 2- 19

Measuring flatness 2- 21

2-18

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Making Measurements

Measuring Laser Separation

Channel separation

Sup p ose that you want to measure sep aration on a system having the

sp ectrum shown in the following figure.

The Agilent 86120C displays separation on this spectrum as shown in

the following figure. Notice that the 1541.747 nm laser line is selected

as the reference. It is shown in absolute units. The wavelengths and

powers of the remaining responses are shown relative to this refer-

ence. For example, the first response is 2.596 nm below the reference.

To determine channel spacing, simply read the relative wavelength

measurement of the laser lines immediately p receding and following

the reference. Use the

, and SELECT softkeys to change the ref-

erence laser line and read the channel sp acing between each channel.

2-19

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Making Measurements

Measuring Laser Separation

To measure channel separation

1 Press the front- panel Preset key.

2 Press List by WL.

3 Press the Delta On key.

Use the Off key to turn off the measurement.

4 Select the typ e of sep aration to observe:

• ∆ WL displays channel separation.

• ∆ WL / ∆ PWR displays both channel separation and differences in

power.

5 Use the

and

softkeys to select the reference laser line.

6 Press SELECT.

Press SELECT at any time to select a new reference. Press RESET at any

time to turn off the delta calculation.

2-20

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Making Measurements

Measuring Laser Separation

Measuring flatness

You can use relative power measurements to measure flatness (pre-

emphasis) in a WDM system. Simply select one carrier as the reference

and measure the remaining carriers relative to the reference level. The

p ower differences rep resent the system flatness.

Press RESET to turn off the delta calculations so that all responses are

shown in absolute wavelength and p owers.

To measure flatness

1 Press the front- panel Preset key.

2 Press List by Power.

This lists the inp ut signals by p ower with the largest resp onse listed

first.

3 Press the Delta On key.

4 Select ∆ PWR.

5 Use the

and

softkeys to select the first laser line.

6 Press SELECT.

7 Since the largest power signal is the reference, the relative power

measurements for the other responses shows system flatness.

2-21

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Making Measurements

Measuring Laser Drift

In this section, you’ll learn how the Agilent 86120C can be used to

monitor drift (changes to a laser’s wavelength and amplitude over

time). Drift is measured simultaneously for every laser line that is

identified at the input. The Agilent 86120C keeps track of each laser

line’s initial, current, minimum, and maximum values and disp lays

their differences relative to itself. This allows the Agilent 86120C to be

used for laser transmitter evaluation, burn- in, or develop ment. In

addition, you can monitor system performance over time, temperature,

or other condition.

The following display shows power and wavelength drift measured on

five laser lines. The DRIFT annotation, item 1, tells you that drift mea-

surements are being performed. The current relative drift values for

wavelength and p ower are shown in items 2 and 3, resp ectively.

Item 4 indicates the absolute reference values for the laser line indi-

cated by the cursor

measurement starts.

. The reference values are measured before the

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Making Measurements

Measuring Laser Drift

You can restart the drift measurement at any time by p ressing the

RESET softkey. All minimum and maximum values are reset to the ref-

erence values, and the Agilent 86120C begins to monitor drift from the

current laser line values. Move the cursor up and down the listing to

see the reference wavelength and power of each laser line.

If measurement updating stops or the values become blanked

If, in the middle of a measurement, the number of laser lines present changes, the

measurement stops until the original number of lines returns. You’ll notice that a

CLEAR softkey appears and one of the following message is displayed:

E46 NUM LINES < NUM REFS

E47 NUM LINES > NUM REFS

To view the data measured before the conditions changed, press CLEAR and

then MAX-MIN. Notice that the measurement acquisition is changed from con-

tinuous to single.

To restart testing, press CLEAR, the CONT key, and then RESET to use the new

number of lines as the reference. Pressing CONT restarts continuous measure-

ment acquisition. Or, you can restore the original number of lines on the input

so that the drift measurement can continue.

To measure drift

1 Press the front- panel Preset key.

2 Press Peak WL, List by WL, or List by Power to select the display style for

observing drift.

3 Press Appl’s and then DRIFT.

Pressing DRIFT sets the current laser- line values as the reference from

which to compare all drift.

4 Press MAX-MIN for the desired type of drift measurement as described

in the following p aragrap hs:

Display shows the current values of laser lines relative to the

wavelength and power values measured when the test was

begun or the RESET softkey was pressed.

Display shows absolute maximum values since the drift

measurement was started. This measurement gives the longest

wavelength and greatest power measured. The laser line of

interest may have since drifted to a lesser value. Note that the

2-23

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Making Measurements

Measuring Laser Drift

maximum wavelength and maximum power may not have

occurred simultaneously.

Display shows absolute minimum values since the drift

measurement was started. This measurement gives the shortest

wavelength and smallest power measured. The laser line of

interest may have since drifted to a greater value. Note that the

minimum wavelength and minimum power may not have

occurred simultaneously.

Display shows the total drift from the reference since the drift

measurement was started. Values represent the minimum

wavelength and power drift values subtracted from the

maximum drift values.

5 In the List by WL and List by Power displays, use the

and

softkeys

to view the reference values (wavelength and power values of each laser

line before the test was started).

During the measurement, you can change the display mode to Peak WL,

List by WL, List by Power, or Avg WL. When List by WL or List by Power is

selected, the signal list is sorted by reference values and not by the

current, maximum, or minimum values.

To restart the drift measurements, p ress RESET. This resets the refer-

ence values.

2-24

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Making Measurements

Measuring Signal-to-Noise Ratios

Signal- to- noise measurements provide a direct indication of system

performance. Signal- to- noise measurements are especially important in

WDM systems because there is a direct relation between signal- to-

noise and bit error rate. The Agilent 86120C displays signal- to- noise

measurements in the third column. For example, the selected signal in

the following figure has a signal- to-noise ratio of 30.0 dB.

Signal-to-noise display.

During a signal- to- noise measurement, the absolute p ower of the car-

rier, in dBm, is comp ared to the absolute p ower of the noise at the

carrier wavelength. See the following figure. The noise p ower at the

carrier must be determined by interpolation because the carrier, in

most cases, can not or should not be turned off.

You can select one of two methods used to determine the wavelength

where the noise is measured: automatic interpolation or a user- entered

wavelength. In the figure above, notice that “S/N AUTO” is displayed

to indicate that automatic interpolation is selected.

2-25

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Making Measurements

Measuring Signal-to-Noise Ratios

Location of noise measurements

Automatic

When the signal- to- noise “auto” function is selected, the

interpolation

Agilent 86120C first determines the proximity of any adjacent signal. If

the next closest signal is ≤200 GHz (approximately 1.6 nm at 1550 nm)

away from the signal of interest, then the noise p ower is measured

half way between the two channels and an equal distance to the other

side of the signal of interest. See points P_n1and P_n2in the following

figure.

If the closest signal is more than 200 GHz from the signal of interest,

or if there is no other signals p resent, then the noise p ower is mea-

sured at 100 GHz on either side of the signal of interest. The two mea-

sured noise power levels are then averaged to estimate the noise

p ower level at the signal wavelength. The noise p ower measurements

use linear interpolation to estimate the noise power level at the signal

of interest’s wavelength.

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Making Measurements

Measuring Signal-to-Noise Ratios

Automatic interpolation

User- entered

wavelength

When the signal- to- noise “user” function is selected, the

Agilent 86120C uses only one wavelength to measure the noise power

for all signals. This wavelength is set by the user and all signals are

compared to the noise level at this wavelength to determine their cor-

responding signal- to- noise ratios.

Noise bandwidth

When measuring noise power, the Agilent 86120C must account for the

noise bandwidth used during the measurement. Because noise band-

width varies with measurement bandwidth (a wide bandwidth allows

more noise to the Agilent 86120C’s detector than a narrow bandwidth),

the Agilent 86120C normalizes all noise power measurements to a

bandwidth of 0.1 nm. The annotation 0.1 nm is displayed to show

that the noise bandwidth is being normalized to a 0.1 nm bandwidth.

Repetitive data formats

The Agilent 86120C signal-to-noise application works best when the laser being

tested is not modulated, or modulated with non-repetitive data formats. With

repetitive data formats, such as PRBS data and SONET formats, there is signifi-

cant low-frequency amplitude modulation of the laser. This modulation raises the

noise floor of the Agilent 86120C significantly. The signal-to-noise measured can

be limited to about 15 dB while measuring lasers modulated by repetitive data for-

mats. For improved performance when the laser is modulated with repetitive data

formats, use the Signal-to-Noise with Averaging application.

2-27

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Making Measurements

Measuring Signal-to-Noise Ratios

To measure signal- to- noise

1 Press the front- panel Preset key.

2 Press List by WL or List by Power.

3 Press Appl’s and then S/N.

4 To select the wavelength reference for measuring the noise, do the

following steps:

a Press WL REF, and

•

press AUTO to let the instrument interpolate the wavelength,

press USER to select the last wavelength manually entered.

b If you chose USER, you can specify the wavelength by pressing USER

WL. Use the

the and

softkey to select the digit that requires editing. Use

softkeys to change the value.

c Press RETURN.

5 While the signal- to- noise measurements are displayed, you can press

PEAK anytime to select the signal with the highest p ower.

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Making Measurements

Measuring Signal-to-Noise Ratios with Averaging

Measuring Signal-to-Noise Ratios with

Averaging

When the lasers being measured are modulated, especially with repeti-

tive data formats such as SONET or PRBS, the noise floor is raised.

Averaging reduces the noise floor and allows an improvement of

greater than 10 dB in a signal- to- noise measurement. In general, aver-

aging will decrease the noise floor caused by modulation until the true

optical noise level is reached. The displayed signal- to- noise will

improve with each average until the true optical noise level is reached,

and then the displayed signal- to- noise will remain approximately con-

stant. If, however, the true signal- to- noise is below the instrument

sensitivity of ap p roximately 40 dB (in a 0.1 nm noise bandwidth), it

will not be measured.

Averaging can also imp rove the accuracy of measuring signal- to- noise

of unmodulated lasers.

Signal-to-noise with averaging display.

Averaging is p erformed on the noise, not on the wavelength or p ower

of the laser signals.

The signal- to- noise with averaging measurement uses the automatic

interpolation method to determine the wavelengths where the noise is

measured. See "Measuring Signal- to- Noise Ratios" for a descrip tion of

automatic interp olation. There is no user- entered wavelength selection

in signal- to- noise with averaging.

During a signal- to- noise with averaging measurement, the disp lay indi-

cates

S/N A xx, where A indicates averaging and xx is the number of

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Making Measurements

Measuring Signal-to-Noise Ratios with Averaging

averages taken so far. The maximum number of averages is 900, the

minimum number of averages is 10, and the default (Preset) value is

100 averages. A measurement with 100 averages takes about 2 minutes

to comp lete. When the measurement is comp lete, the instrument

switches to single measurement mode. Then, pressing the Cont key will

start a comp letely new measurement. During a measurement and

before the number of averages has been reached, pressing the Single

key will stop the measurement. Then, p ressing the Cont key will con-

tinue with the current measurement.

While making a signal- to- noise with averaging measurement, the num-

ber of averages can be changed. As long as the new number of aver-

ages is greater than the number of averages taken so far, the

measurement continues. If the new number of averages selected is less

than the number of averages taken so far, the measurement stop s and

the instrument switches to single measurement mode. Then, pressing

the Cont key will start a comp letely new measurement.

Noise bandwidth

affects

measurement

When measuring noise power, the Agilent 86120C must account for the

noise bandwidth used during the measurement. Because noise band-

width varies with measurement bandwidth (a wide bandwidth allows

more noise to the Agilent 86120C’s detector than a narrow bandwidth),

the Agilent 86120C normalizes all noise power measurements to a

bandwidth of 0.1 nm. The annotation 0.10 nm is displayed to show

that the noise bandwidth is being normalized to a 0.1 nm bandwidth.

To measure signal- to- noise with averaging

1 Press the front panel Preset key.

2 Press List by WL or List by Power.

3 Press Appl's and then S/N AVG.

4 To change the number of averages, press NUM AVG. The default (Preset)

value is 100.

5 To stop the measurement at the current number of averages shown,

press the Single key. Then p ress the Cont key to continue the present

measurement.

6 When the measurement is comp lete, the instrument will switch to the

single measurement mode and stop.

7 To make a new measurement, press the Cont key.

8 To exit, p ress the EXIT softkey, then press the Cont key for continuous

measurement.

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Making Measurements

Measuring Fabry-Perot (FP) Lasers

The Agilent 86120C can perform several measurements on Fabry- Perot

lasers including FWHM and mode sp acing. The disp lay shows the mea-

surement results in the selected wavelength and amplitude units. In

addition, the mode spacing measurement always shows results in fre-

quency as well as the selected wavelength units. Refer to “Displayed

units” on page 2- 12 to learn how to change the units. The number of

laser lines included in the measurement results is also listed as shown

in the following figure.

To characterize a Fabry- Perot laser

1 Press Appl’s.

2 Press FP TEST to measure the Fabry-Perot laser’s characteristics.

If you want to stop the up dating of measurement data with each

sweep, press Single. Because Fabry- Perot lasers are sensitive to reflec-

tions it is good measurement p ractice to p lace an op tical isolator or

attenuator between the laser and the Agilent 86120C.

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Making Measurements

Measuring Fabry-Perot (FP) Lasers

Measurement

FWHM

Description

FWHM (full width at half maximum) describes the spectral

width of the half-power points of the laser, assuming a

continuous, Gaussian power distribution. The half-power points

are those where the power spectral density is one-half that of

the peak amplitude of the computed Gaussian curve.

FWHM = 2.355 σ

where, σ is sigma as defined below.

MEAN

The wavelength representing the center of mass of selected

peaks. The power and wavelength of each spectral component

are used to calculate the mean wavelength.

λ_i

MeanWavelength =

P_i

P_°

i =1

where, P_ois total power as defined in this section.

MODE

PEAK

The mean wavelength spacing between the individual spectral

components of the laser.

The power level of the peak spectral component of the laser.

The wavelength of the peak spectral component.

SIGMA

An rms calculation of the spectral width of the laser based on a

Gaussian distribution. The power and wavelength of each

spectral component is used to calculate mean wavelength.

(λ_i– λ)²

---------------------

σ =

P_i

P_o

i = 1

where:

λ is the mean wavelength as defined above.

P_iis the power of a single peak.

P_ois total power as defined in this section.

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Making Measurements

Measuring Fabry-Perot (FP) Lasers

PWR

The summation of the power in each of the selected peaks, or

modes, that satisfy the peak-excursion and peak-threshold

criteria.

Total Power =

P_i

i =1

The peak excursion and peak threshold settings define the laser modes

included in the measurement. Because the default peak excursion value

is 10 dB, measurement results normally include all laser modes within

10 dB of the peak response. Use the PK THLD softkey to change the

number of laser modes used in the measurements. Refer to “Defining

Laser- Line Peaks” on page 2- 15 for information on the peak threshold

and peak excursion settings.

The peak excursion value (in dB) can also be used to determine which

side modes are included in the measurements. To be accep ted, each

trace p eak must rise, and then fall, by at least the p eak excursion

value about a given spectral component. Setting the peak-excursion

value too high results in failure to include the smaller resp onses near

the noise floor. Setting the value too low may cause unwanted

responses, including noise spikes, to be identified. Use PK EXC to

change the peak excursion value.

2-33

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Making Measurements

Measuring Modulated Lasers

A laser that is amp litude modulated at low frequencies (for examp le,

modulated in the audio frequency range) can cause sp urious wave-

lengths to be displayed below and above the correct wavelength. The

power of these spurious wavelengths is below that of the correct

wavelength. These spurious signals can be eliminated by decreasing the

peak threshold. Refer to “Defining Laser-Line Peaks” on p age 2- 15

Even when the laser is amplitude modulated, the correct wavelength

and power is displayed.

The sp urious wavelengths caused by low frequency amp litude modula-

tion will be located above and below the correct wavelength by the fol-

lowing wavelength spacing:

spacing = 6×10^–10Fλ²

where F is the modulation frequency in Hz, and λ is the correct wave-

length in nm. For examp le, an amp litude modulation of 10 kHz on a

1550 nm laser will p roduce sp urious wavelengths sp aced by 15 nm

from the correct wavelength, and the sp urious wavelengths will be at

1535 and 1565 nm.

Low frequency (10 kHz) AM modulation graph showing rounded sideband spurs.

2-34

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Making Measurements

Measuring Modulated Lasers

The graphical display is useful for locating these spurious wavelengths.

Their amp litude will be below that of the correct wavelength and they

will be broad, rounded p eaks comp ared to the sharp p eak of the cor-

rect wavelength. Use the Peak Threshold function to p lace the dotted

line above the spurious peaks so they will not be displayed in the List

by WL or List by Power table.

A laser modulated at high frequency (in the RF or microwave range)

can also cause sp urious wavelengths to be disp layed, esp ecially when

the modulation is of a rep etitive nature such as that of PRBS or

SONET digital formats. In general, no spurious wavelengths will be dis-

played using preset instrument conditions. The preset condition

includes peak excursion, peak threshold, and wavelength range limit-

ing. However, increasing peak threshold can cause spurious wave-

lengths to be displayed.

Even when the laser being tested is modulated with repetitive formats,

the carrier’s correct wavelength and p ower is disp layed; the wave-

length and p ower of the sp urious sidebands are incorrect.

The grap hical disp lay is useful to see the effects of high frequency

modulation. Without modulation, the noise floor is typically 45 dB

below the laser power. In general, high frequency modulation will raise

the noise floor to about 25 dB below the laser p ower. The noise floor

is typ ically flat, or white. The actual level of the noise floor dep ends

on the typ e of data format and the data rate.

PRBS modulation graph showing raised noise floor.

2-35

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Making Measurements

Measuring Total Power Greater than 10 dBm

The maximum total power that can be measured by the Agilent 86120C

is 10 dBm. However, with the addition of an external attenuator, more

power can be app lied. This may be necessary at the transmit end of a

wavelength- division- multiplexed system where large signal levels are

p resent. By entering an amp litude offset equal to the amount of atten-

uation at the instrument’s input, accurate amplitude measurements are

shown on the disp lay. Additional amp lification can also be accounted

for.

C A U T IO N

The maximum total input power that can be applied to the Agilent 86120C

before damage occurs is 18 dBm. The maximum total input power that can be

measured is 10 dBm.

To measure total power exceeding 10 dBm

1 Connect an optical attenuator between the front- panel OPTICAL INPUT

connector and the fiber- optic cable.

The attenuator must reduce the total input power to the Agilent 86120C

so that it is below +10 dBm.

2 Press Setup, MORE, CAL, and then PWR OFS.

Notice that the PWR OFSannotation ap p ears on the screen to indicate

an offset is ap p lied.

3 Use the

4 Use the

softkey to select the digit that requires editing.

and softkeys to change the value.

Power offset values are added to the disp lay p ower readings. For

examp le, if you p laced a 10 dB attenuator on the front- p anel connec-

tor, enter a p ower offset value of +10 dB. Negative values can also be

entered if you connect an amp lifier instead of an attenuator.

2-36

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Making Measurements

Calibrating Measurements

The wavelength of light changes depending on the material that the

light is p assing through. To disp lay meaningful wavelength measure-

ments, the Agilent 86120C performs two steps:

1 Measures the wavelength in air.

2 Converts the wavelength to show values in either a vacuum or “standard

air”.

For examp le, a laser line with a wavelength of 1550.000 nm in a vac-

uum would have a wavelength in standard air of 1549.577 nm.

Because all measurements made inside the Agilent 86120C are p er-

formed in air, the density of air, due to elevation, affects the wave-

length results. You must calibrate the Agilent 86120C by entering the

elevation. Elevations from 0 to 5000 meters can be entered. The eleva-

tion correction is immediately applied to the current measurement

even if the instrument is in the single measurement acquisition mode.

Annotation on the display shows the current calibration elevation in

meters and whether the wavelength measurements are shown for a

vacuum (VAC) or standard air (STD AIR).

If you select frequency instead of wavelength measurements, switching

between vacuum and standard air will not affect the measurement

results. This is because the frequency of an op tical signal does not

change in different mediums—only the wavelength changes.

Definition of standard air

Standard air is defined to have the following characteristics:

Barometric pressure: 1013 mbar

Temperature:

Relative humidity:

15°C

2-37

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Making Measurements

Calibrating Measurements

To enter the elevation

1 Press the Setup key.

2 Press the MORE softkey.

3 Press the CAL softkey.

4 Press ELEV.

5 Use the

and

softkeys to enter the elevation in meters. Entries

jump in 500 meter steps from 0 m to 5000 m.

In order for the Agilent 86120C to meet its published specifications, the

elevation value selected with the softkeys must be within 250 meters of

the actual elevation.

6 Press RETURN to comp lete the entry.

Converting feet to meters

If you know your elevation in feet, you can convert this value to meters by using

the following equation:

3,281

------------

m =

To select the medium for light

1 Press the Setup key.

2 Press the MORE softkey.

3 Press the CAL softkey, and make the following selection:

• Press VACUUM for wavelengths in a vacuum.

• Press STD AIR for wavelengths in standard air.

4 Press RETURN to comp lete the entry.

2-38

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Making Measurements

Printing Measurement Results

Measurement results can be sent directly to a printer. Simply connect

a compatible printer to the rear- panel PARALLEL PRINTER PORT con-

nector. The output is ASCII text. An example of a compatible printer is

Hewlett- Packard^®’s LaserJet¹series p rinter. Be sure to use a p arallel

p rinter cable to connect the p rinter.

The p rinter outp ut is not a cop y of the disp lay. Rather, it is a listing

of all signals present at the input (up to 200). The measurement values

printed dep end on the settings of the instrument when the Print key is

pressed. The following is an example of a typical printout:

Agilent 86120C SER US39400020

Firmware Ver. 1.000

List By Wavelength

8 Lines

Power Offset 0.0 dB

Vacuum

Elevation 0 Meters

Update Normal

Peak Excursion 15 dB

Peak Threshold 10 dB

Device Narrow

Input

Wavelength

Power

1280.384nm

1281.473

1282.569

1283.651

1284.752

1285.840

1286.944

1288.034

-16.97dBm

-13.14

-13.92

-13.34

-11.69

-8.11

-10.38

-14.65

To create a hardcopy

1 Connect the printer to the Agilent 86120C’s rear- panel PARALLEL

PRINTER PORT connector.

2 Press Print. You can use the ABORT and CONT softkey to stop and restart

a p rint job that is in p rogress.

1. Hewlett-Packard and LaserJet are registered trademarks of Hewlett-Packard Company.

2-39

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Making Measurements

Cleaning Connections for Accurate Measurements

Cleaning Connections for Accurate

Measurements

Today, advances in measurement capabilities make connectors and

connection techniques more important than ever. Damage to the con-

nectors on calibration and verification devices, test p orts, cables, and

other devices can degrade measurement accuracy and damage instru-

ments. Rep lacing a damaged connector can cost thousands of dollars,

not to mention lost time! This expense can be avoided by observing

the simp le precautions presented in this book. This book also contains

a brief list of tips for caring for electrical connectors.

Choosing the Right Connector

A critical but often overlooked factor in making a good lightwave mea-

surement is the selection of the fiber- op tic connector. The differences

in connector typ es are mainly in the mechanical assembly that holds

the ferrule in position against another identical ferrule. Connectors

also vary in the polish, curve, and concentricity of the core within the

cladding. Mating one style of cable to another requires an adap ter.

Agilent Technologies offers adapters for most instruments to allow

testing with many different cables. Figure 2- 3 on page 2- 41 shows the

basic components of a typical connectors.

The system tolerance for reflection and insertion loss must be known

when selecting a connector from the wide variety of currently available

connectors. Some items to consider when selecting a connector are:

• How much insertion loss can be allowed?

• Will the connector need to make multiple connections? Some connectors

are better than others, and some are very poor for making repeated

connections.

• What is the reflection tolerance? Can the system take reflection degra-

dation?

2-40

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Making Measurements

Cleaning Connections for Accurate Measurements

• Is an instrument- grade connector with a precision core alignment re-

quired?

• Is rep eatability tolerance for reflection and loss imp ortant? Do your

specifications take repeatability uncertainty into account?

• Will a connector degrade the return loss too much, or will a fusion

splice be required? For example, many DFB lasers cannot operate with

reflections from connectors. Often as much as 90 dB isolation is needed.

Figure 2-3. Basic components of a connector.

Over the last few years, the FC/PC style connector has emerged as the

most p op ular connector for fiber-op tic ap p lications. While not the

highest performing connector, it represents a good compromise

between performance, reliability, and cost. If properly maintained and

cleaned, this connector can withstand many repeated connections.

However, many instrument sp ecifications require tighter tolerances

than most connectors, including the FC/PC style, can deliver. These

instruments cannot tolerate connectors with the large non- concentrici-

ties of the fiber common with ceramic style ferrules. When tighter

alignment is required, Agilent Technologies instruments typically use a

connector such as the Diamond HMS-10, which has concentric toler-

ances within a few tenths of a micron. Agilent Technologies then uses

a sp ecial universal adap ter, which allows other cable typ es to mate

with this precision connector. See Figure 2- 4.

2-41

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Making Measurements

Cleaning Connections for Accurate Measurements

Figure 2-4. Universal adapters to Diamond HMS-10.

The HMS- 10 encases the fiber within a soft nickel silver (Cu/Ni/Zn)

center which is surrounded by a tough tungsten carbide casing, as

shown in Figure 2- 5.

Figure 2-5. Cross-section of the Diamond HMS-10 connector.

The nickel silver allows an active centering p rocess that p ermits the

glass fiber to be moved to the desired p osition. This p rocess first

stakes the soft nickel silver to fix the fiber in a near-center location,

then uses a p ost- active staking to shift the fiber into the desired p osi-

tion within 0.2 µm. This process, plus the keyed axis, allows very pre-

cise core- to-core alignments. This connector is found on most Agilent

Technologies lightwave instruments.

2-42

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Making Measurements

Cleaning Connections for Accurate Measurements

The soft core, while allowing p recise centering, is also the chief liabil-

ity of the connector. The soft material is easily damaged. Care must be

taken to minimize excessive scratching and wear. While minor wear is

not a problem if the glass face is not affected, scratches or grit can

cause the glass fiber to move out of alignment. Also, if unkeyed con-

nectors are used, the nickel silver can be p ushed onto the glass sur-

face. Scratches, fiber movement, or glass contamination will cause loss

of signal and increased reflections, resulting in p oor return loss.

Inspecting Connectors

Because fiber- optic connectors are susceptible to damage that is not

immediately obvious to the naked eye, poor measurements result with-

out the user being aware. Microscop ic examination and return loss

measurements are the best way to ensure good measurements. Good

cleaning p ractices can help ensure that op timum connector p erfor-

mance is maintained. With glass- to- glass interfaces, any degradation of

a ferrule or the end of the fiber, any stray particles, or finger oil can

have a significant effect on connector performance. Where many repeat

connections are required, use of a connector saver or p atch cable is

recommended.

Figure 2- 6 shows the end of a clean fiber- op tic cable. The dark circle

in the center of the micrograph is the fiber’s 125 µm core and cladding

which carries the light. The surrounding area is the soft nickel- silver

ferrule. Figure 2- 7 shows a dirty fiber end from neglect or p erhap s

improper cleaning. Material is smeared and ground into the end of the

fiber causing light scattering and poor reflection. Not only is the preci-

sion polish lost, but this action can grind off the glass face and destroy

the connector.

Figure 2- 8 shows p hysical damage to the glass fiber end caused by

either rep eated connections made without removing loose p articles or

using improper cleaning tools. When severe, the damage of one con-

nector end can be transferred to another good connector endface that

comes in contact with the damaged one. Periodic checks of fiber ends,

and replacing connecting cables after many connections is a wise prac-

tice.

The cure for these problems is disciplined connector care as described

in the following list and in “Cleaning Connectors” on page 2- 47.

2-43

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Making Measurements

Cleaning Connections for Accurate Measurements

Use the following guidelines to achieve the best possible performance

when making measurements on a fiber- optic system:

• Never use metal or sharp objects to clean a connector and never scrape

the connector.

• Avoid matching gel and oils.

Figure 2-6. Clean, problem-free fiber end and ferrule.

Figure 2-7. Dirty fiber end and ferrule from poor cleaning.

2-44

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Making Measurements

Cleaning Connections for Accurate Measurements

Figure 2-8. Damage from improper cleaning.

While these often work well on first insertion, they are great dirt mag-

nets. The oil or gel grabs and holds grit that is then ground into the

end of the fiber. Also, some early gels were designed for use with the

FC, non- contacting connectors, using small glass spheres. When used

with contacting connectors, these glass balls can scratch and p it the

fiber. If an index matching gel or oil must be used, ap p ly it to a

freshly cleaned connector, make the measurement, and then immedi-

ately clean it off. Never use a gel for longer- term connections and

never use it to imp rove a damaged connector. The gel can mask the

extent of damage and continued use of a damaged fiber can transfer

damage to the instrument.

• When inserting a fiber-optic cable into a connector, gently insert it in

as straight a line as possible. Tipping and inserting at an angle can

scrape material off the inside of the connector or even break the inside

sleeve of connectors made with ceramic material.

• When inserting a fiber- optic connector into a connector, make sure that

the fiber end does not touch the outside of the mating connector or

adapter.

• Avoid over tightening connections.

Unlike common electrical connections, tighter is not better. The p ur-

p ose of the connector is to bring two fiber ends together. Once they

touch, tightening only causes a greater force to be applied to the deli-

cate fibers. With connectors that have a convex fiber end, the end can

be pushed off- axis resulting in misalignment and excessive return loss.

Many measurements are actually imp roved by backing off the connec-

2-45

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Making Measurements

Cleaning Connections for Accurate Measurements

tor pressure. Also, if a piece of grit does happen to get by the cleaning

procedure, the tighter connection is more likely to damage the glass.

Tighten the connectors just until the two fibers touch.

• Keep connectors covered when not in use.

• Use fusion sp lices on the more p ermanent critical nodes. Choose the

best connector possible. Replace connecting cables regularly. Frequently

measure the return loss of the connector to check for degradation, and

clean every connector, every time.

All connectors should be treated like the high-quality lens of a good

camera. The weak link in instrument and system reliability is often the

inappropriate use and care of the connector. Because current connec-

tors are so easy to use, there tends to be reduced vigilance in connec-

tor care and cleaning. It takes only one missed cleaning for a p iece of

grit to permanently damage the glass and ruin the connector.

Measuring insertion loss and return loss

Consistent measurements with your lightwave equip ment are a good

indication that you have good connections. Since return loss and inser-

tion loss are key factors in determining optical connector performance

they can be used to determine connector degradation. A smooth, p ol-

ished fiber end should p roduce a good return-loss measurement. The

quality of the polish establishes the difference between the “PC” (phys-

ical contact) and the “Super PC” connectors. Most connectors today are

physical contact which make glass- to-glass connections, therefore it is

critical that the area around the glass core be clean and free of

scratches. Although the major area of a connector, excluding the glass,

may show scratches and wear, if the glass has maintained its p olished

smoothness, the connector can still p rovide a good low level return

loss connection.

If you test your cables and accessories for insertion loss and return

loss up on receip t, and retain the measured data for comp arison, you

will be able to tell in the future if any degradation has occurred. Typ -

ical values are less than 0.5 dB of loss, and sometimes as little as 0.1

dB of loss with high performance connectors. Return loss is a measure

of reflection: the less reflection the better (the larger the return loss,

the smaller the reflection). The best physically contacting connectors

have return losses better than 50 dB, although 30 to 40 dB is more

common.

2-46

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Making Measurements

Cleaning Connections for Accurate Measurements

Visual inspection of fiber ends

Visual insp ection of fiber ends can be help ful. Contamination or

imperfections on the cable end face can be detected as well as cracks

or chip s in the fiber itself. Use a microscop e (100X to 200X magnifica-

tion) to inspect the entire end face for contamination, raised metal, or

dents in the metal as well as any other imperfections. Inspect the fiber

for cracks and chips. Visible imperfections not touching the fiber core

may not affect p erformance (unless the imp erfections keep the fibers

from contacting).

WA R N IN G

Always remove both ends of fiber-optic cables from any instrument,

system, or device before visually inspecting the fiber ends. Disable all

optical sources before disconnecting fiber-optic cables. Failure to do

so may result in permanent injury to your eyes.

Cleaning Connectors

The p rocedures in this section p rovide the p rop er step s for cleaning

fiber-optic cables and Agilent Technologies universal adapters. The ini-

tial cleaning, using the alcohol as a solvent, gently removes any grit

and oil. If a caked- on layer of material is still p resent, (this can hap -

pen if the beryllium- copper sides of the ferrule retainer get scraped

and deposited on the end of the fiber during insertion of the cable), a

second cleaning should be p erformed. It is not uncommon for a cable

or connector to require more than one cleaning.

2-47

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Making Measurements

Cleaning Connections for Accurate Measurements

C A U T IO N

Agilent Technologies strongly recommends that index matching compounds

not be applied to their instruments and accessories. Some compounds, such as

gels, may be difficult to remove and can contain damaging particulates. If you

think the use of such compounds is necessary, refer to the compound

manufacturer for information on application and cleaning procedures.

Table 2-2. Cleaning Accessories

Item

Agilent Part Number

Any commercially available denatured alcohol

Cotton swabs

—

5080-5400

Table 2-3. Dust Caps Provided with Lightwave Instruments

Item

Agilent Part Number

FC/PC dust cap

DIN dust cap

08154-44102

08154-44103

08154-44101

HMS10/dust cap

To clean a non- lensed connector

C A U T IO N

Do not use any type of foam swab to clean optical fiber ends. Foam swabs can

leave filmy deposits on fiber ends that can degrade performance.

1 Ap p ly p ure isop rop yl alcohol to a clean lint- free cotton swab or lens

paper.

Cotton swabs can be used as long as no cotton fibers remain on the

fiber end after cleaning.

2 Clean the ferrules and other parts of the connector while avoiding the

end of the fiber.

3 Ap p ly isop rop yl alcohol to a new clean lint- free cotton swab or lens

2-48

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Making Measurements

Cleaning Connections for Accurate Measurements

paper.

4 Clean the fiber end with the swab or lens paper.

Do not scrub during this initial cleaning because grit can be caught in

the swab and become a gouging element.

5 Immediately dry the fiber end with a clean, dry, lint- free cotton swab

or lens paper.

6 Blow across the connector end face from a distance of 6 to 8 inches

using filtered, dry, compressed air. Aim the compressed air at a shallow

angle to the fiber end face.

Nitrogen gas or comp ressed dust remover can also be used.

C A U T IO N

Do not shake, tip, or invert compressed air canisters, because this releases

particles in the can into the air. Refer to instructions provided on the

compressed air canister.

7 As soon as the connector is dry, connect or cover it for later use.

If the performance, after the initial cleaning, seems poor try cleaning

the connector again. Often a second cleaning will restore p rop er p er-

formance. The second cleaning should be more arduous with a scrub-

bing action.

To clean an adapter

The fiber- op tic inp ut and outp ut connectors on many Agilent Technol-

ogies instruments employ a universal adapter such as those shown in

the following p icture. These adap ters allow you to connect the instru-

ment to different types of fiber- optic cables.

Figure 2-9. Universal adapters.

1 Ap p ly isop rop yl alcohol to a clean foam swab.

Cotton swabs can be used as long as no cotton fibers remain after clean-

ing. The foam swabs listed in this section’s introduction are small

enough to fit into adapters.

2-49

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Making Measurements

Cleaning Connections for Accurate Measurements

Although foam swabs can leave filmy deposits, these deposits are very

thin, and the risk of other contamination buildup on the inside of adapt-

ers greatly outweighs the risk of contamination by foam swabs.

2 Clean the adapter with the foam swab.

3 Dry the inside of the adapter with a clean, dry, foam swab.

4 Blow through the adap ter using filtered, dry, comp ressed air.

Nitrogen gas or comp ressed dust remover can also be used. Do not

shake, tip, or invert compressed air canisters, because this releases par-

ticles in the can into the air. Refer to instructions provided on the com-

p ressed air canister.

2-50

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Addressing and Initializing the Instrument 3- 3

To change the GPIB address 3-4

Making Measurements 3- 5

Commands are grouped in subsystems 3-7

Measurement instructions give quick results 3-9

The format of returned data 3-15

Monitoring the Instrument 3- 16

Status registers 3-17

Queues 3-22

Reviewing SCPI Syntax Rules 3- 23

Example Programs 3- 28

Example 1. Measure a DFB laser 3-30

Example 2. Measure WDM channels 3-32

Example 3. Measure WDM channel drift 3-34

Example 4. Measure WDM channel separation 3-37

Example 5. Measure signal-to-noise ratio of each WDM channel 3-39

Example 6. Increase a source’s wavelength accuracy 3-41

Lists of Commands 3- 43

Programming

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Programming

This chapter explains how to program the Agilent 86120C. The pro-

gramming syntax conforms to the IEEE 488.2 Standard Digital Inter-

face for Programmable Instrumentation and to the Standard

Commands for Programmable Instruments (SCPI).

Where to begin…

The programming examples for individual commands in this manual

are written in HP¹BASIC 6.0 for an HP 9000 Series 200/300 Control-

ler.

For more detailed information regarding the GPIB, the IEEE 488.2

standard, or the SCPI standard, refer to the following books:

Hewlett-Packard Company. Tutorial Description of Hewlett- Packard

Interface Bus, 1987.

Hewlett-Packard Company. SCPI—Standard Commands for Program-

mable Instruments, 1995.

International Institute of Electrical and Electronics Engineers. IEEE

Standard 488.1- 1987, IEEE Standard Digital Interface for Programma-

ble Instrumentation. New York, NY, 1987.

International Institute of Electrical and Electronics Engineers. IEEE

Standard 488.2- 1987, IEEE Standard Codes, Formats, Protocols and

Common commands For Use with ANSI/IEEE Std 488.1- 1987. New York,

NY, 1987.

Types of commands

The Agilent 86120C responds to three types of commands:

• Common commands

• Measurement instructions

• Subsystem commands

All of these commands are documented in Chapter 4, “Programming

Commands”.

1. HP is a registered trademark of Hewlett-Packard Company.

3-2

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Programming

Addressing and Initializing the Instrument

The Agilent 86120C’s GPIB address is configured at the factory to a

value of 20. You must set the outp ut and inp ut functions of your p ro-

gramming language to send the commands to this address. You can

change the GPIB address from the front p anel as described in

change the GPIB address” on p age 3- 4 .

“To

Remote mode and front- panel lockout

Whenever the instrument is controlled by a comp uter, the Remote

message is displayed on the instrument’s screen and the softkey menu

is blanked except for the LOCAL softkey. This softkey can be p ressed

by the user to restore front p anel control of the instrument.

You can specify a local lockout mode that prevents the LOCAL softkey

from being displayed. If the instrument is in local lockout mode, all the

softkeys may be blanked. For example, if the instrument is first placed

in local lockout mode and then placed in remote mode, no softkeys are

displayed.

Consult the documentation for your programming environment to

determine which commands are used to p ut an instrument in the

remote and local lockout modes. These are not Agilent 86120C com-

mands; they control GPIB control lines and do not send any characters

to the Agilent 86120C.

Initialize the instrument at start of every program

It is good p ractice to initialize the instrument at the start of every

program. This ensures that the bus and all appropriate interfaces are

in a known state. HP BASIC provides a CLEAR command which clears

the interface buffer and also resets the instrument’s p arser. (The

p arser is the p rogram that reads the instructions that you send.)

Whenever the instrument is under remote p rogramming control, it

should be in the single measurement acquisition mode. This is auto-

matically accomplished when the *RST common command is used. The

*RST command initializes the instrument to a p reset state:

CLEAR 720

OUTPUT 720;”*RST”

3-3

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Programming

Addressing and Initializing the Instrument

Notice in the examp le above, that the commands are sent to an instru-

ment address of 720. This indicates address 20 on an interface with

select code 7. Pressing the green Preset key does not change the GPIB

address.

Set single acquisition mode

An advantage of using the *RST command is that it sets the

Agilent 86120C into the single measurement acquisition mode. Because

the READ and MEASure data queries expect this mode, their proper

operation is ensured.

To change the GPIB address

1 Press the Setup key.

2 Press MORE twice, then GPIB.

3 Use the

and

softkeys to change the GPIB address.

4 Press RETURN.

3-4

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Programming

Making Measurements

Making measurements remotely involves changing the Agilent 86120C’s

settings, performing a measurement, and then returning the data to

the computer. The simplified block diagram of the Agilent 86120C

shown here lists some of the available p rogramming commands. Each

command is p laced next to the instrument section it configures or

queries data from.

Notice that there are two buffers from which data can be queried: an

uncorrected data buffer and a corrected data buffer. With each scan of

the input wavelength range, the analog- to- digital converter loads

65,536 data values into the uncorrected data buffer. This is considered

to be one “measurement”. A fast- update measurement mode is avail-

able for quicker measurement acquisition. But, because only 32,768

data values are collected in fast- update measurement mode, the ability

to resolve closely sp aced signals is reduced.

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Programming

Making Measurements

After collecting the uncorrected data, the Agilent 86120C searches the

data for the first 200 p eak resp onses. (For WLIMit:OFF, searching

starts at 1650 nm and progresses towards 1270 nm. For WLIMit:ON,

searching starts at WLIMit:START and p rogresses toward

WLIMit:STOP.) These p eak values are then p laced into the corrected

data buffer. Each p eak value consists of an amplitude and wavelength

measurement. Amplitude and wavelength correction factors are applied

to this data.

For a listing of the p rogramming commands (including a cross refer-

ence to front- p anel keys), refer to the following tables:

Table 3-10, “Programming Commands,” on page 3- 43

Table 3-11, “Keys Versus Commands,” on page 3- 48

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Programming

Making Measurements

Commands are grouped in subsystems

The Agilent 86120C commands are grouped in the following sub-

systems. You’ll find a description of each command in Chapter 4, “Pro-

gramming Commands”.

Subsystem

Purpose of Commands

Measurement

Instructions

Perform frequency, wavelength, and wavenumber

measurements.

CALCulate1

CALCulate2

CALCulate3

Queries uncorrected frequency-spectrum data.

Queries corrected peak data and sets wavelength limits.

Performs delta, drift, signal-to-noise, and Fabry-Perot

measurements.

DISPlay

HCOPy

SENSe

Applies markers and displays power bars.

Prints measurement results.

Sets elevation-correction values, selects readings for air or

vacuum, and enters amplitude offsets. Queries time-domain

values of the input data.

STATus

SYSTem

TRIGger

Queries instrument status registers.

Presets Agilent 86120C and queries error messages.

Stops current measurement. Acquires new measurement data.

Also used to select single or continuous acquisition of

measurement data.

UNIT

Sets the amplitude units to watts or dBm.

Table 2-4 on page 3- 8 shows the kinds of measurements that the

Agilent 86120C can p erform and the associated p rogramming com-

mands used to return that data. In some cases, there is more than one

method that can be used to obtain the desired data. Refer to Chapter

4, “Programming Commands” for the correct syntax for these com-

mands.

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Programming

Making Measurements

Table 2-4. Commands for Capturing Data

Desired

Measurement

Command to Configure Measurement

(partial listing)

Command to Query Data

Wavelength (nm)

CONFigure, FETCh, READ, and MEASure

MEASure:ARRay:POWer:WAVelengt

Frequency (THz)

CONFigure, FETCh, READ, and MEASure

MEASure:ARRay:POWer:FREQuency

Wavenumber (m^–1)

Power (W, dBm)

CONFigure, FETCh, READ, and MEASure

CALCulate2:PWAVerage:STATe

MEASure:ARRay:POWer:WNUMber?

MEASure:ARRay:POWer?

CALCulate2:DATA?

Average Wavelength,

Wavenumber, or Frequency

Total Power (W, dBm)

Fabry-Perot Laser

CALCulate2:PWAVerage:STATe

CALCulate3:FPERot

CALCulate2:DATA?

Refer to “FPERot[:STATE]” on

page 4-62

Laser-Line Separation

Laser-Line Drift

CALCulate3:DELTa:REFerence

CALCulate3:DRIFt:STATe

CALCulate3:SNR:STATe

CALCulate3:ASNR:STATe

CALCulate3:DATA?

SENSe:DATA?

Signal-to-Noise Ratio

Signal-to-Noise Ratio Average

Time-Domain Data

CALCulate1:TRANsform:FREQuency:POINt

Corrected Frequency Domain

Data

CALCulate1:TRANsform:FREQuency:POINt

CALCulate2:DATA?

CALCulate1:DATA?

Uncorrected Frequency Domain

Data

CALCulate1:TRANsform:FREQuency:POINt

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Programming

Making Measurements

Measurement instructions give quick results

The easiest way to measure wavelength, frequency, or power is to use

the MEASure command. The MEASure command is one of four mea-

surement instructions: MEASure, READ, FETCh, and CONFigure. The

syntax for measurement instructions is documented in “Measurement

Instructions” on page 4- 15.

Each measurement instruction has an argument that controls the mea-

surement up date rate. This is equivalent to using the

NORMAL and

FAST softkeys.

:MEASure command

MEASure configures the Agilent 86120C, captures new data, and que-

ries the data all in one step . For examp le, to measure the longest

wavelength, send the following command:

:MEASure:SCALar:POWer:WAVelength? MAX

Table 2-5. The Different Forms of MEASure

Desired

Measurement Data

Use this

MEASure Query

Display Format

Power (W, dBm)

Frequency (Hz)

:MEASure:ARRay:POWer?

List by Power

:MEASure:SCALar:POWer?

single wavelength mode

List by WL (frequency)

single wavelength mode

List by WL

:MEASure:ARRay:POWer:FREQuency?

:MEASure:SCALar:POWer:FREQuency?

MEASure:ARRay:POWer:WAVelength?

MEASure:SCALar:POWer:WAVelength?

:MEASure:ARRay:POWer:WNUMber?

:MEASure:SCALar:POWer:WNUMber?

Wavelength (m)

Wavenumber (m^–1)

single wavelength mode

List by WL

single wavelength mode

Sp ecifying SCALar p laces the disp lay in the single wavelength format

and returns a single value to the comp uter. Sp ecifying ARRay p laces

the display in the List by Power or List by WL modes; an array of data is

returned to the computer.

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Programming

Making Measurements

A common p rogramming error is to send the :MEASure command

when the instrument is in the continuous measurement acquisition

mode. Because :MEASure contains an :INIT:IMM command, which

expects the single measurement acquisition mode, an error is gener-

ated, and the INIT command is ignored.

:READ command

The READ command works like the MEASure command except that it

does not configure the instrument’s settings. You can use the CONFig-

ure command to configure the instrument for a particular measure-

ment without returning any data.

The MEASure and READ commands are identical to combining the fol-

lowing commands:

Command

:MEASure

:READ

Equivalent Commands

:ABORt;:CONFigure;:READ

:ABORt;:INITiate:IMMediate;:FETCh

A common p rogramming error is to send the :READ command when

the instrument is in the continuous measurement acquisition mode.

Because :READ contains an :INIT:IMM command, which expects the

single measurement acquisition mode, an error is generated, and the

INIT command is ignored.

:FETCh command

The FETCh command returns data from previously performed mea-

surements; it does not initiate the collection of new data. Because

FETCh does not configure the instrument or acquire new inp ut data,

you can use FETCh repeatedly on the same set of acquired data. For

example, use two FETCh commands to return wavelength and then

p ower values for the same measurement. This is shown in the follow-

ing program fragment:

OUTPUT 720;”:INIT:CONT OFF;”

OUTPUT 720;”:CONF:ARR:POW MAX”

OUTPUT 720;”:INIT:IMM”

OUTPUT 720;”:FETC:ARR:POW?”

ENTER 720:powers$

OUTPUT 720;”:FETC:ARR:POW:WAV?”

ENTER 720:wavelengths$

In the example above, the data in the power and wavelength arrays are

returned in the same order so that p owers can be matched to wave-

lengths.

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Programming

Making Measurements

Also, because new data is not collected, FETCh is especially useful

when characterizing transient data.

FETCh does not reconfigure the disp lay. For examp le, if the disp lay is

in the Peak WL mode, sending :FETCh:ARRay does not configure the

display to the List by WL even though an array of data is returned to

the computer.

A common p rogramming error occurs when the :FETCh command is

used after an *RST command. This generates error number –230,

“Data corrupt or stale”. In this instance, you must send :INIT:IMM

after the *RST command and before the :FETCh command to capture a

new array of measurement data.

:CONFigure command

The CONFigure command changes measurement settings without taking

a measurement. The instrument is p laced in the List by WL, List by

Ampl, or Peak WL display application.

CONFigure can be queried. The query returns the last configuration

setup by the CONFigure command. The instrument returns a string

which is the last instrument function sent by a CONFigure command

or MEASure query. The returned string is in the short command form.

Use caution when using this query, because if any instrument settings

were changed since the last CONFigure command or MEASure query

these changes may not be included in the returned string.

For examp le, if the last CONFigure command was:

:CONFigure:SCALar:POWer:WAVelength 1300NM, MAX

a CONFigure? query would return a string that is similar to the follow-

ing line:

“POW:WAV 1.300000e-6,0.01”

The 1300NM and resolution values track the actual instrument settings

and input signals. Notice that the quotation marks are part of the

returned string.

Return single or multiple measurement values

You can specify whether FETCh, READ, or MEASure returns a single

value (SCALar) or multiple values (ARRay). The following example

specifies SCALar data which returns a single value.

:MEASure:SCALar:POWer:WAVelength? MAX

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Programming

Making Measurements

ARRay and the SCPI standard

According to the SCPI command reference, the ARRay command causes an instru-

ment to take multiple measurements. (A <size> parameter indicates the number

of measurements to take.) However, the Agilent 86120C’s ARRay command refers

to the measurements performed for one measurement sweep; this results in an

array of measured signals. Because the <size> parameter does not apply, any

<size> parameter sent will be ignored by the instrument. No syntax error will be

generated if a <size> parameter is sent.

Always force the Agilent 86120C to wait for non-sequential com-

mands

The Agilent 86120C normally processes its remote programming com-

mands sequentially. The instrument waits until the actions specified by

a p articular command are comp letely finished before reading and exe-

cuting the next command. However, there are a few non- sequential

commands where this is not true. Non- sequential commands do not

finish executing before the next command is interp reted.

The following is a list of the Agilent 86120C’s non- sequential com-

mands:

:CALCulate1:TRANsform:FREQuency:POINTs

:CALCulate2:PEXCursion

:CALCulate2:PTHReshold

:CALCulate2:WLIMit:STARt:FREQuency

:CALCulate2:WLIMit:STARt:WAVelength

:CALCulate2:WLIMit:STARt:WNUMber

:CALCulate2:WLIMit:STOP:FREQuency

:CALCulate2:WLIMit:STOP:WAVelength

:CALCulate2:WLIMit:STOP:WNUMber

:CALCulate3:SNR:AUTO

:SENSe:CORRection:ELEVation

:INITiate:CONTinuous

:INITiate[:IMMediate]

The following additional commands are also non- sequential commands

if CALCulate3:SNR:AUTO is set to OFF:

:CALCulate3:REFerence:FREQuency

:CALCulate3:REFerence:WAVelength

:CALCulate3:REFerence:WNUMber

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Programming

Making Measurements

The benefit of non- sequential commands is that, in some situations,

they can reduce the overall execution times of programs. For example,

you can set the peak excursion, peak threshold, and elevation and use

a *WAI command at the end to save time. However, non- sequential

commands can also be a source of annoying errors. Always use the

*OPC query or *WAI command with the non- sequential commands to

ensure that your programs execute properly.

For examp le, sup p ose that you wanted to set the elevation correction

value and then send an :INIT:IMM command. The following p rogram-

ming fragment results in an error “–213 Init ignored”. This occurs

because the :ELEVation command causes the recalculation of the data

which is like sending the :INIT:IMM command. When the actual

:INIT:IMM is sent, the error occurs because the command is already in

progress.

OUTPUT 720;”:INIT:IMM”

OUTPUT 720;”:SENSe:CORRection:ELEVation 1000”

OUTPUT 720;”:INIT:IMM”

Use an *OPC? query to ensure that the :ELEVation command has com-

pleted as shown in the following lines:

OUTPUT 720;”:INIT:IMM”

OUTPUT 720;”:SENSe:CORRection:ELEVation 1000”

OUTPUT 720;”*OPC?”

ENTER 720;Response$

OUTPUT 720;”:INIT:IMM”

Or, the *WAI command could be used:

OUTPUT 720;”:INIT:IMM”

OUTPUT 720;”:SENSe:CORRection:ELEVation 1000”

OUTPUT 720;”*WAI?”

OUTPUT 720;”:INIT:IMM”

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Programming

Making Measurements

Measure delta, drift, and signal-to- noise

To select a measurement, use one of the following STATe commands:

CALC3:DELT:POW:STAT (delta power)

CALC3:DELT:WAV:STAT (delta wavelength)

CALC3:DELT:WPOW:STAT (delta power and wavelength)

CALC3:DRIF:STAT (drift)

CALC3:SNR:STAT (signal-to-noise ratios)

CALC3:ASNR:STAT (signal-to-noise ratio averaging)

If you select a drift measurement, you can select one of the following

additional states:

CALC3:DRIF:DIFF:STAT (difference)

CALC3:DRIF:MAX:STAT (maximum drift)

CALC3:DRIF:MIN:STAT (minimum drift)

CALC3:DRIF:REF:STAT (drift reference values)

The :CALCulate3:DRIFt:PRESet command turns off the minimum, max-

imum, difference, and reference states but leaves the drift state on.

Attemp ting to turn more than one state on at a time results in an

“–221 Settings Conflict” error.

The *RST and SYSTem:PRESet commands turn all calculations off.

CALCulate3:PRESet turns off any CALCulate3 calculations.

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Programming

Making Measurements

The format of returned data

Measurements are returned as strings

All measurement values are returned from the Agilent 86120C as

ASCII strings. When an array is returned, the individual values are

separated by the comma character.

Determine the number of data points

When a FETCh, READ, or MEASure command is used (with ARRay

sp ecified), the first returned value indicates the total number of mea-

surement values returned in the query.

If you use the:CALCulate1:DATA?, :CALCulate2:DATA?, or

:CALCulate3:DATA? queries to query data, send the :POINts? query

first to determine the number of values returned in the string. The

string does not contain a first value which specifies the string length.

This is shown in the following examp le:

OUTPUT 720;”:CALCulate1:POINts?”

ENTER 720;Length

OUTPUT 720;”:CALCulate1:DATA?”

ENTER 720;Result$

Data can be corrected for elevation and vacuum

Normally, the Agilent 86120C provides measurement values calculated

for conditions in air at sea level. Use the :SENSe:CORRection:ELEVa-

tion command to comp ensate for air disp ersion. Altitudes up to 5000

meters can be entered. Use the :SENSe:CORRection:MEDium command

to switch to readings in a vacuum.

Amplitude units

The default amp litude units are dBm. If you need measurements in

watts, use the :UNIT:POWer command. When the Agilent 86120C is

turned on, the amp litude units are automatically set to the units used

before the instrument was last turned off.

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Programming

Monitoring the Instrument

Almost every p rogram that you write will need to monitor the

Agilent 86120C for its operating status. This includes querying execu-

tion or command errors and determining whether or not measure-

ments have been completed. Several status registers and queues are

provided to accomplish these tasks.

In this section, you’ll learn how to enable and read these registers. In

addition to the information in this section, you should review the com-

mands documented in “Common Commands” on page 4- 3 and “STATus

Subsystem” on page 4- 90.

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Programming

Monitoring the Instrument

Status registers

The Agilent 86120C p rovides four registers which you can query to

monitor the instrument’s condition. These registers allow you to deter-

mine the following items:

• Status of an operation

• Availability of the measured data

• Reliability of the measured data

All four registers are shown in the figure on the following p age and

have the following uses:

Definition

Status Byte

Monitors the status of the other three registers.

Standard Event Status

This is the standard IEEE 488.2 register. Contains

bits which indicate the status of the other two regis-

ters.

OPERation Status

Contains bits that report on the instrument’s normal

operation.

QUEStionable Status

Contains bits that report on the condition of the sig-

nal.

Status Byte register

The Status Byte Register contains summary bits that monitor activity

in the other status registers and queues. The Status Byte Register’s

bits are set and cleared by the presence and absence of a summary bit

from other registers or queues. Notice in the following figure that the

bits in the Standard Event Status, OPERation status, and QUEStionable

status registers are “or’d” to control a bit in the Status Byte Register.

If a bit in the Status Byte Register goes high, you can query the value

of the source register to determine the cause.

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Programming

Monitoring the Instrument

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Programming

Monitoring the Instrument

The Status Byte Register can be read using either the *STB? common

command or the GPIB serial poll command. Both commands return the

decimal- weighted sum of all set bits in the register. The difference

between the two methods is that the serial poll command reads bit 6

as the Request Service (RQS) bit and clears the bit which clears the

SRQ interrup t. The *STB? command reads bit 6 as the Master Sum-

mary Status (MSS) and does not clear the bit or have any effect on the

SRQ interrupt. The value returned is the total bit weights of all of the

bits that are set at the p resent time.

OPERation Status and QUEStionable Status registers

You can query the value of the OPERation Status and QUEStionable

Status registers using commands in the STATus subsystem.

The STATus subsystem also has transition filter software which give

you the ability to select the logic transitions which set bits in the

OPERation Status and QUEStionable Status registers. For example, you

can define the POWer bit of the QUEStionable Status register to report

an event when the condition transitions from false to true. This is a

positive transition. You can also specify a negative transition where the

bit is set when the condition transitions from true to false.

Table 3-6. Bits in Operation Status Register

Bit

Definition

not used

SETTling - indicating that the instrument is waiting for the motor to reach

the proper position before beginning data acquisition.

RANGing - indicating the instrument is currently gain ranging.

not used

MEASuring - indicating that the instrument is making a measurement.

5 through 8

not used

Processing - indicating that the instrument is currently processing the

data acquired.

Hardcopy - indicating that the instrument is currently printing the data to

the parallel port.

Averaging - indicating that the instrument is in the process of averaging

the noise for the signal-to-noise ratio calculation.

12 through 16

not used

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Programming

Monitoring the Instrument

Table 3-7. Bits in Questionable Status Register

Bit

Definition

0, 1, and 2

not used

POWer - indicating that the instrument is measuring too high of a power.

3 through 8

not used

Maximum signals - indicating that the instrument has found the

maximum number of signals.

Drift Reference - indicating that the number of reference signals is

different from the current number of input signals.

Delta Reference - indicating that there is no delta reference signal.

12 through 13

not used

Command Warning - indicating that the instrument has received some

extra unexpected parameters for one of the measurement functions.

not used

Standard Event Status register

The Standard Event Status Register monitors the following instrument

status events:

• OPC - Op eration Comp lete

• RQC - Request Control

• QYE - Query Error

• DDE - Device Dep endent Error

• EXE - Execution Error

• CME - Command Error

• URQ - User Request

• PON - Power On

When one of these events occur, the event sets the corresp onding bit

in the register. If the bits are enabled in the Standard Event Status

Enable Register, the bits set in this register generate a summary bit to

set bit 5 (ESB) in the Status Byte Register.

The contents of the Standard Event Status Register can be read and

the register cleared by sending the *ESR? query. The value returned is

the total bit weights of all of the bits that are set at the p resent time.

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Programming

Monitoring the Instrument

Enabling register bits with masks

Several masks are available which you can use to enable or disable

individual bits in each register. For example, you can disable the Hard-

copy bit in the OPERation Status Register so that even though it goes

high, it can never set the summary bit in the status byte high.

Use the *SRE common command to set or query the mask for the Sta-

tus Byte Register.

The masks for the OPERation Status and QUEStionable Status registers

are set and queried using the STATus subsystem’s ENABle commands.

Use the *ESE common command to set or query the mask for the

Standard Event Status Register.

The *CLS common command clears all event registers and all queues

excep t the outp ut queue. If *CLS is sent immediately following a p ro-

gram message terminator, the output queue is also cleared. In addition,

the request for the *OPC bit is also cleared.

For example, suppose your application requires an interrupt whenever

any type of error occurs. The error related bits in the Standard Event

Status Register are bits 2 through 5. The sum of the decimal weights of

these bits is 60. Therefore, you can enable any of these bits to generate

the summary bit by sending the *ESE 60 command.

Whenever an error occurs, it sets one of these bits in the Standard

Event Status Register. Because the bits are all enabled, a summary bit

is generated to set bit 5 in the Status Byte Register.

If bit 5 (ESB) in the Status Byte Register is enabled (via the *SRE

command), an SRQ service request interrup t is sent to the external

computer.

Standard Event Status Register bits that are not enabled still resp ond

to their corresp onding conditions (that is, they are set if the corre-

sp onding event occurs). However, because they are not enabled, they

do not generate a summary bit to the Status Byte Register.

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Programming

Monitoring the Instrument

Queues

There are two queues in the instrument: the output queue and the

error queue. The values in the outp ut queue and the error queue can

be queried.

Output queue

The output queue stores the instrument responses that are generated

by certain commands and queries that you send to the instrument. The

outp ut queue generates the Message Available summary bit when the

output queue contains one or more bytes. This summary bit sets the

MAV bit (bit 4) in the Status Byte Register. The method used to read

the Outp ut Queue dep ends up on the p rogramming language and envi-

ronment. For examp le, with HP BASIC, the outp ut queue may be read

using the ENTER statement.

Error queue

As errors are detected, they are p laced in an error queue. Instrument

specific errors are indicated by positive values. General errors have

negative values. You can clear the error queue by reading its contents,

sending the *CLS command, or by cycling the instrument’s power.

The error queue is first in, first out. If the error queue overflows, the

last error in the queue is rep laced with error - 350, “Queue overflow.”

Any time the queue overflows, the least recent errors remain in the

queue, and the most recent error is discarded. The length of the

instrument’s error queue is 30 (29 p ositions for the error messages,

and 1 position for the “Queue overflow” message).

The error queue is read with the SYSTEM:ERROR? query. Executing

this query reads and removes the oldest error from the head of the

queue, which opens a p osition at the tail of the queue for a new error.

When all the errors have been read from the queue, subsequent error

queries return 0, “No error.”

For more information on reading the error queue, refer to “ERRor” on

page 4- 98. For a list of errors messages, refer to “Error Messages” on

page 7- 11.

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Programming

Reviewing SCPI Syntax Rules

SCPI command are grouped in subsystems

In accordance with IEEE 488.2, the instrument’s commands are

grouped into “subsystems.” Commands in each subsystem perform sim-

ilar tasks. The following subsystems are provided:

Measurement Instructions

Calculate1 Subsystem

Calculate2 Subsystem

Calculate3 Subsystem

Display Subsystem

Hcopy Subsystem

Sense Subsystem

Status Subsystem

System Subsystem

Trigger Subsystem

Unit Subsystem

Sending a command

It’s easy to send a command to the instrument. Simply create a com-

mand string from the commands listed in this book, and p lace the

string in your p rogram language’s outp ut statement. For commands

other than common commands, include a colon before the subsystem

name. For example, the following string places the cursor on the peak

laser line and returns the p ower level of this p eak:

OUTPUT 720;”:MEAS:SCAL:POW? MAX”

Use either short or long forms

Commands and queries may be sent in either long form (comp lete

sp elling) or short form (abbreviated sp elling). The descrip tion of each

command in this manual shows both versions; the extra characters for

the long form are shown in lowercase. The following is a long form of

a command:

OUTPUT 720;”:MEASure:SCALar:POWer? MAXimum”

And this is the short form of the same command:

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Programming

Reviewing SCPI Syntax Rules

OUTPUT 720;”:MEAS:SCAL:POW? MAX”

Programs written in long form are easily read and are almost self- doc-

umenting. Using short form commands conserves the amount of con-

troller memory needed for program storage and reduces the amount of

I/O activity.

The rules for creating short forms from the long form is as follows:

The mnemonic is the first four characters of the keyword unless the

fourth character is a vowel, in which case the mnemonic is the first

three characters of the keyword.

This rule is not used if the length of the keyword is exactly four char-

acters.

Table 3-8. Examples of Short Forms

Long Form

Equivalent Short Form

ROUTE

LAYER

ROUT

LAY

SYSTEM

ERROR

SYST

ERR

You can use upper or lowercase letters

Program headers can be sent using any combination of uppercase or

lowercase ASCII characters. Instrument responses, however, are always

returned in uppercase.

Combine commands in the same subsystem

You can combine commands from the same subsystem provided that

they are both on the same level in the subsystem’s hierarchy. Simp ly

separate the commands with a semi- colon (;). For example, the follow-

ing two lines,

OUTPUT 720;”:CALC2:PEXC 12”

OUTPUT 720;”:CALC2:PTHR 20”

can be combined into one line:

OUTPUT 720;”:CALC2:PEXC 12;PTHR 20”

The semicolon sep arates the two functions.

3-24

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Programming

Reviewing SCPI Syntax Rules

Combine commands from different subsystems

You can send commands and program queries from different sub-

systems on the same line. Simp ly p recede the new subsystem by a

semicolon followed by a colon. In the following example, the colon and

semicolon p air before DISP allows you to send a command from

another subsystem.

OUTPUT 720;”:CALC2:PEXC 12;:DISP:WIND:GRAP:STAT OFF”

Sending common commands

If a subsystem has been selected and a common command is received

by the instrument, the instrument remains in the selected subsystem.

For examp le, if the p rogram message

”DISPLAY:MARK:MAX:LEFT;*CLS;DISP:MARK:MAX:RIGH”

is received by the instrument, the Disp lay subsystem remains selected.

If some other type of command is received within a program message,

you must reenter the original subsystem after the command.

Adding parameters to a command

Many commands have p arameters that sp ecify an op tion. Use a sp ace

character to separate the parameter from the command as shown in

the following line:

OUTPUT 720;”:INIT:CONT ON”

Sep arate multip le p arameters with a comma (,). Sp aces can be added

around the commas to imp rove readability.

OUTPUT 720;”:MEAS:SCAL:POW:FREQ? 1300, MAX”

White space

White sp ace is defined to be one or more characters from the ASCII

set of 0 through 32 decimal, excluding 10 (NL). White sp ace is usually

optional, and can be used to increase the readability of a program.

Numbers

All numbers are expected to be strings of ASCII characters. Thus,

when sending the number 9, you would send a byte rep resenting the

ASCII code for the character “9” (which is 57). A three-digit number

like 102 would take up three bytes (ASCII codes 49, 48, and 50). This

3-25

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Programming

Reviewing SCPI Syntax Rules

is taken care of automatically when you include the entire instruction

in a string. Several rep resentations of a number are p ossible. For

example, the following numbers are all equal:

0.28E2

280E-1

28000m

0.028K

28E-3K

If a measurement cannot be made, no resp onse is given and an error

is p laced into the error queue. For examp le,

*RST

FETCh:POW?

will timeout the controller and p lace a Data stale or corrupt error in

the error queue.

Table 3-9. Suffix Multipliers

Multiplier

Mnemonic

1E18

1E15

1E12

1E9

1E6

1E3

1E-3

1E-6

1E-9

1E-12

1E-15

1E-18

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Programming

Reviewing SCPI Syntax Rules

Program message terminator

The string of instructions sent to the instrument are executed after the

instruction terminator is received. The terminator may be either a

new- line (NL) character, the End- Or- Identify (EOI) line asserted, or a

combination of the two. All three ways are equivalent. Asserting the

EOI sets the EOI control line low on the last byte of the data message.

The NL character is an ASCII linefeed (decimal 10). The NL terminator

has the same function as an EOS (End Of String) and EOT (End Of

Text) terminator.

Querying data

Data is requested from the instrument using a query. Queries can be

used to find out how the instrument is currently configured. They are

also used to get results of measurements made by the instrument, with

the query actually activating the measurement. String responses are

returned as upper- case letters.

Queries usually take the form of a command followed by a question

mark (?). After receiving a query, the instrument places the answer in

its outp ut queue. The answer remains in the outp ut queue until it is

read or another command is issued. For example, the query

OUTPUT 720;”:CALCULATE2:POINTS?”

places the number of points in the data set in the output queue. In HP

BASIC, the controller inp ut statement:

ENTER 720;Range

passes the value across the bus to the controller and places it in the

variable Range. A newline character is appended to the response.

Sending another command or query before reading the result of a

query causes the outp ut queue to be cleared and the current resp onse

to be lost. This also generates an error in the error queue.

The outp ut of the instrument may be numeric or character data

depending on what is queried. Refer to the specific commands for the

formats and types of data returned from queries.

You can send multip le queries to the instrument within a single p ro-

gram message, but you must also read them back within a single p ro-

gram message. This can be accomp lished by either reading them back

into a string variable or into multip le numeric variables. When you

read the result of multip le queries into string variables, each response

is separated by a semicolon.

3-27

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Programming

Example Programs

The following example programs are provided in this section:

Example 1. Measure a DFB laser 3- 30

Example 2. Measure WDM channels 3- 32

Example 3. Measure WDM channel drift 3- 34

Example 4. Measure WDM channel separation 3- 37

Example 5. Measure signal- to- noise ratio of each WDM channel 3- 39

Example 6. Increase a source’s wavelength accuracy 3- 41

These programs are provided to give you examples of using

Agilent 86120C remote programming commands in typical applications.

They are not meant to teach general p rogramming techniques or p ro-

vide ready- to- use solutions. They should allow you to see how mea-

surements are p erformed and how to return data to the comp uter.

All of the examp les are written in the HP BASIC p rogramming lan-

guage.

Many subroutines are repeated in the examples

The first five example programs contain several common subroutines.

These routines, along with one function, are described in the rest of

this introduction. The descrip tions are listed in the general order that

the subroutines are called in the programs.

Error_msg subroutine

This function is found in examp les 2, 3, 4, and 5. It disp lays an error

message on the computer’s screen explaining the reason that the pro-

gram’s execution stop p ed.

Set_ese subroutine

The subroutine sets the enable mask for the event status register to a

value of 52. This allows bits 2, 4, and 5 to be set whenever a query

error (QYE), execution error (EXE), or command error (CME) respec-

tively occurs. All this is accomp lished using the *ESE common com-

mand.

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Programming

Example Programs

The Err_mngmt subroutine is used to actually read the value of the

event status register. Examples 1 through 5 call this subroutine.

FNIdentity function

When this function is called, it resets the instrument and queries the

instrument’s identification string which is disp layed on the comp uter’s

screen by the calling function. To accomplish this task, the FNIdentity

function uses the *RST, *OPC?, and *IDN? common commands. This

function is called from Examples 1 through 5.

Err_mngmt subroutine

This subroutine checks to make sure that no errors have set bits in the

event status register and that there are no errors in the queue. Exiting

this subroutine is only possible if no errors have occurred. Notice that

the logic test in the subroutine tests for the same event status register

bits enabled by the Set_ese subroutine: BIT(Cme,5), BIT(Cme,4),

BIT(Cme,2).

This subroutine is called in Examples 1 through 5. However, it is mod-

ified in Examp les 3, 4, and 5 to allow it to indicate the last p rogram-

ming command that was sent to the instrument before an error

occurred. This is accomp lished by adding an op tional argument string.

Cmd_opc subroutine

The Cmd_op c subroutine, found in Examp les 3, 4, and 5, p auses the

program until a non- sequential command has finished executing on the

Agilent 86120C. It uses the *OPC? query.

For more information on non- sequential commands, refer to “Always

force the Agilent 86120C to wait for non-sequential commands” on

page 3- 12.

Tempo subroutine

This subroutine, which is only found in Examp le 3, p auses the p ro-

gram for a few seconds while the Agilent 86120C measures the drift

on a laser. The argument in the example sets the pause for 10 seconds.

3-29

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Programming

Example Programs

Example 1. Measure a DFB laser

This p rogram measures the p ower and wavelength of a DFB laser. It

first sets the Agilent 86120C in the single-acquisition measurement

mode. Then, it triggers the Agilent 86120C with the MEASure com-

mand to capture measurement data of the input spectrum. Because the

data is stored in the instrument’s memory, it can be queried as

needed.

Refer to the introduction to this section for a description of each sub-

routine that is contained in this program.

COM /Instrument/ @Mwm

ASSIGN @Mwm TO 720

Set_ese

PRINT USING "37A,33A";"Multi-Wavelength Meter Identity is : ";FNIdentity$

OUTPUT @Mwm;":INIT:CONT OFF"

ON TIMEOUT 7,5 CALL Err_mngmt

OUTPUT @Mwm;":MEAS:SCAL:POW:WAV?"

ENTER @Mwm;Current_wl

OUTPUT @Mwm;":FETC:SCAL:POW?"

ENTER @Mwm;Current_pwr

OFF TIMEOUT

PRINT USING "20A,4D.3D,3A,19A,M2D.2D,4A";"The wavelength is : ";Current_wl /1.0E-9;" nm";" with a

power of : ";Current_pwr;" dBm"

END

Err_mngmt:SUB Err_mngmt

COM /Instrument/ @Mwm

DIM Err_msg$[255]

INTEGER Cme

CLEAR 7

REPEAT !

OUTPUT @Mwm;"*ESR?"

ENTER @Mwm;Cme

OUTPUT @Mwm;":SYST:ERR?"

ENTER @Mwm;Err_msg$

PRINT Err_msg$

UNTIL NOT BIT(Cme,2) AND NOT BIT(Cme,4) AND NOT BIT(Cme,5) AND

POS(Err_msg$,"+0")

Subend:SUBEND

Set_ese:SUB Set_ese

COM /Instrument/ @Mwm

OUTPUT @Mwm;"*ESE ";IVAL("00110100",2)

SUBEND

3-30

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Programming

Example Programs

Identity:DEF FNIdentity$;

COM /Instrument/ @MwmV

DIM Identity$[50]

Identity$=""

OUTPUT @Mwm;"*RST"

OUTPUT @Mwm;"*OPC?"

ENTER @Mwm;Opc_done

OUTPUT @Mwm;"*IDN?"

ENTER @Mwm;Identity$

RETURN Identity$

FNEND

3-31

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Programming

Example Programs

Example 2. Measure WDM channels

This p rogram measures the multip le laser lines of a WDM system. It

measures both the p ower and wavelengths of each line. First, the p ro-

gram sets the Agilent 86120C in the single- acquisition measurement

mode. Then, it triggers the Agilent 86120C with the MEASure com-

mand to capture measurement data of the input spectrum. Because the

data is stored in the instrument’s memory, it can be queried as

needed.

Refer to the introduction to this section for a description of each sub-

routine that is contained in this program.

COM /Instrument/ @Mwm

ASSIGN @Mwm TO 720

ON ERROR GOTO Error_msg,

Set_ese

PRINT USING "37A,33A";"Multi-Wavelength Meter Identity is : ";FNIdentity$

OUTPUT @Mwm;":INIT:CONT OFF"

ON TIMEOUT 7,5 CALL Err_mngmt

OUTPUT @Mwm;":MEAS:ARR:POW:WAV?"

ENTER @Mwm USING "#,K";Nb_wl

ALLOCATE Current_wl(1:Nb_wl)

ENTER @Mwm USING "#,K";Current_wl(*)

OUTPUT @Mwm;":FETC:ARR:POW?"

ENTER @Mwm USING "#,K";Nb_wl

ALLOCATE Current_pwr(1:Nb_wl)

ENTER @Mwm USING "#,K";Current_pwr(*)

FOR I=1 TO Nb_wl

PRINT USING "22A,2D,6A,4D.2DE,4A,S2D.2D,3A";"The wavelength number

";Current_wl(I);" at ";Current_pwr(I);"dBm"

NEXT I

OFF TIMEOUT

STOP

Error_msg:

PRINT "the prgm is aborted due to : ";ERRM$

END

Err_mngmt:SUB Err_mngmt

COM /Instrument/ @Mwm

DIM Err_msg$[255]

INTEGER Cme

CLEAR 7

REPEAT

OUTPUT @Mwm; "*ESR?"

ENTER @Mwm;Cme

OUTPUT @Mwm; ":SYST:ERR?"

ENTER @Mwm;Err_msg$

3-32

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Programming

Example Programs

PRINT Err_msg$

UNTIL NOT BIT(Cme,2) AND NOT BIT(Cme,4) AND NOT BIT(Cme,5) AND

Err$,"+0")

Subend:SUBEND

Set_ese:SUB Set_ese

COM /Instrument/ @Mwm

OUTPUT @Mwm; "*ESE";IVAL("00110100",2)

SUBEND

Identity:DEF FNIdentity$;

COM /Instrument/ @Mwm

DIM Identity$[50]

Identity$=""

OUTPUT @Mwm;"*RST"

OUTPUT @Mwm;"*OPC?"

ENTER @Mwm;Opc_done

OUTPUT @Mwm;"*IDN?"

ENTER @Mwm;Identity$

RETURN Identity$

FNEND

3-33

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Programming

Example Programs

Example 3. Measure WDM channel drift

This program measures the drift of channels in a WDM system. It

measures drift in both p ower and wavelength of each line. First, the

program sets the Agilent 86120C in the continuous- acquisition mea-

surement mode. Then, it measures drift using commands from the

CALCulate3 subsystem.

Notice the use of the Temp o subroutine to p ause the p rogram for 10

seconds while the Agilent 86120C measures the drift on the system.

The use of the Err_mngmt subroutine is op tional. Refer to the intro-

duction to this section for a descrip tion of each subroutine that is

contained in this program.

COM /Instrument/ @Mwm

ASSIGN @Mwm TO 720

DIM Key$[1]

ON ERROR GOTO Error_msg

Set_ese

PRINT USING "37A,33A";"Multi-Wavelength Meter Identity is: " ;FNIdentity$

ON TIMEOUT 7,5 CALL Err_mngmt

Cmd_opc("*RST")

Cmd_opc(":INIT:IMM")

Cmd_opc("*OPC")

Cmd_opc(":CONF:ARR:POW:WAV")

! Turn on the drift calculation

Cmd_opc(":CALC3:DRIF:STAT ON")

Err_mngmt(":CALC3:DRIF:STAT ON")

! Turn off all drift states

Cmd_opc(":CALC3:DRIF:PRES")

Err_mngmt(":CALC3:DRIF:PRES")

! Turn on drift reference state

Cmd_opc(":CALC3:DRIF:REF:STAT ON")

Err_mngmt(":CALC3:DRIF:REF:STAT ON")

! Query the number of data points

OUTPUT @Mwm;":CALC3:POIN?"

ENTER @Mwm USING "#,K";Nb_pt

ALLOCATE Current_ref_wl(1:Nb_pt)

ALLOCATE Current_ref_pwr(1:Nb_pt)

3-34

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Programming

Example Programs

! Query reference wavelengths and powers

OUTPUT @Mwm;":CALC3:DATA? WAV"

ENTER @Mwm USING "#,K";Current_ref_wl(*)

OUTPUT @Mwm;":CALC3:DATA? POW"

ENTER @Mwm USING "#,K";Current_ref_pwr(*)

! Turn off drift reference state

Cmd_opc(":CALC3:DRIF:REF:STAT OFF")

Err_mngmt(":CALC3:DRIF:REF:STAT OFF")

! Turn on drift max min calculation

Cmd_opc(":CALC3:DRIF:DIFF:STAT ON")

Err_mngmt(":CALC3:DRIF:DIFF:STAT ON")

Tempo(10)

ALLOCATE Current_diff_wl(1:Nb_pt)

ALLOCATE Current_diff_pw(1:Nb_pt)

! Query drift wavelengths and powers

OUTPUT @Mwm;":CALC3:DATA? WAV"

ENTER @Mwm USING "#,K";Current_diff_wl(*)

OUTPUT @Mwm;":CALC3:DATA? POW"

ENTER @Mwm USING "#,K";Current_diff_pw(*)

OFF TIMEOUT

FOR I=1 TO Nb_pt

PRINT USING "18A,2D,6A,M4D.2DE,3A,21A,MDD.3DE,3A";"Wavelength number "

;I;" is : ";Current_ref_wl(I);" m";" with a drift from : ";Current_diff_wl(I);" m"

PRINT USING "28A,SDD.2DE,4A,20A,MDD.3DE,3A,/";"it has a power level of

: ";Current_ref_pwr(I);" dBm";" with a drift from : ";Current_diff_pw(I);" dB";

NEXT I

STOP

Error_msg: !

PRINT "The program is aborted due to : ";ERRM$

END

Err_mngmt:SUB Err_mngmt(OPTIONAL Cmd_msg$)

COM /Instrument/ @Mwmt

DIM Err_msg$[255]

INTEGER Cme

CLEAR @Mwm

REPEAT

OUTPUT @Mwm;"*ESR?"

ENTER @Mwm;Cme

OUTPUT @Mwm;":SYST:ERR?"

ENTER @Mwm;Err_msg$

IF NPAR>0 AND NOT POS(Err_msg$,"+0") THEN PRINT "This command

";Cmd_msg$;" makes the following error :"

IF NOT POS(Err_msg$,"+0") THEN PRINT Err_msg$

UNTIL NOT BIT(Cme,2) AND NOT BIT(Cme,4) AND NOT BIT(Cme,5) AND

POS(Err_msg$,"+0")

3-35

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Programming

Example Programs

Subend:SUBEND

Set_ese:SUB Set_ese

COM /Instrument/ @Mwm

OUTPUT @Mwm;"*ESE ";IVAL("00110100",2)

SUBEND

Identity:DEF FNIdentity$;

COM /Instrument/ @Mwm

DIM Identity$[50]

Identity$=""

OUTPUT @Mwm;"*RST"

OUTPUT @Mwm;"*OPC?"

ENTER @Mwm;Opc_done

OUTPUT @Mwm;"*IDN?"

ENTER @Mwm;Identity$

RETURN Identity$

FNEND

Cmd_opc:SUB Cmd_opc(Set_cmd$)

COM /Instrument/ @Mwm

OUTPUT @Mwm;Set_cmd$

OUTPUT @Mwm;"*OPC?"

ENTER @Mwm;Opc_done$

SUBEND

Tempo:SUB Tempo(Temp)

FOR I=Temp TO 0 STEP -1)

DISP "Waiting for ";VAL$(I);" sec . . . "

WAIT 1

NEXT I

DISP ""

SUBEND

3-36

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Programming

Example Programs

Example 4. Measure WDM channel separation

This program measures the line separations on a WDM system. It mea-

sures separation (delta) between power and wavelength of each line

using commands from the CALCulate3 subsystem.

Refer to the introduction to this section for a description of each sub-

routine that is contained in this program.

COM /Instrument/ @Mwm

ASSIGN @Mwm TO 720

DIM Key$[1]

ON ERROR GOTO Error_msg

Set_ese

PRINT USING "37A,33A";"Multi-Wavelength Meter Identity is : ";FNIdentity$

ON TIMEOUT 7,5 CALL Err_mngmt

Cmd_opc("*RST")

! Change to list-by-wavelength display

Cmd_opc(":CONF:ARR:POW:WAV")

! Trigger and wait for one measurement

Cmd_opc(":INIT")

Cmd_opc("*WAI")

! Turn on delta mode

Cmd_opc(":CALC3:DELT:WPOW:STAT ON")

! Set first wavelength as reference

Cmd_opc(":CALC3:DELT:REF:WAV MIN")

! Query number of data points

OUTPUT @Mwm;":CALC3:POIN?"

ENTER @Mwm USING "#,K";Nb_pt

ALLOCATE Delta_wl(1:Nb_pt)

ALLOCATE Delta_pwr(1:Nb_pt)

! Query wavelengths and powers

OUTPUT @Mwm;":CALC3:DATA? WAV"

ENTER @Mwm;Delta_wl(*)

OUTPUT @Mwm;":CALC3:DATA? POW"

ENTER @Mwm;Delta_pwr(*)

OFF TIMEOUT

FOR I=1 TO Nb_pt-1

PRINT USING "6A,2D,17A,M4D.3D,31A,S2D.2D,4A";"Line :";I;" wavelength is :

3-37

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Programming

Example Programs

";(Delta_wl(I)+((NOT I=1)*Delta_wl(1)))/1.0E-9;" nm. Absolute line level is :

";Delta_pwr(I)+(NOT I=1)*Delta_pwr(1);" dBm"

PRINT USING "17A,2D,6A,M4D.3D,23A,2D,6A,S2D.2D,3A";"Delta Wl to line ",I+1,"

is : ";(Delta_wl(I+1)-(NOT I=1)*Delta_wl(I))/1.E-9;" nm, Delta Pwr to line ",I+1," is :

";(I=1)*(Delta_pwr(I+1))+(NOT I=1)*(Delta_pwr(I+1)-Delta_pwr(I));" dB"

NEXT I

PRINT USING "6A,2D,17A,M4D.3D,31A,S2D.2D,4A";"Line : ";I;" wavelength is :

";(Delta_wl(1)+Delta_wl(Nb_pt))/1.0E-9;" nm. Absolute line level is : ";Delta_pwr(1)+Delta_pwr(Nb_pt);"

dBm"

STOP

Error_msg: !

PRINT "The program is aborted due to : ";ERRM$

END

Err_mngmt:SUB Err_mngmt(OPTIONAL Cmd_msg$)

COM /Instrument/ @Mwmt

DIM Err_msg$[255]

INTEGER Cme

CLEAR @Mwm

REPEAT

OUTPUT @Mwm;"*ESR?"

ENTER @Mwm;Cme

OUTPUT @Mwm;":SYST:ERR?"

ENTER @Mwm;Err_msg$

IF NPAR>0 AND NOT POS(Err_msg$,"+0") THEN PRINT "This command

";Cmd_msg$;" makes the following error :"

IF NOT POS(Err_msg$,"+0") THEN PRINT Err_msg$

UNTIL NOT BIT(Cme,2) AND NOT BIT(Cme,4) AND NOT BIT(Cme,5) AND

POS(Err_msg$,"+0")

Subend:SUBEND

Set_ese:SUB Set_ese

COM /Instrument/ @Mwm

OUTPUT @Mwm;"*ESE ";IVAL("00110100",2)

SUBEND

Identity:DEF FNIdentity$;

COM /Instrument/ @Mwm

DIM Identity$[33]

Identity$=""

OUTPUT @Mwm;"*RST"

OUTPUT @Mwm;"*OPC?"

ENTER @Mwm;Opc_done

OUTPUT @Mwm;"*IDN?"

ENTER @Mwm;Identity$

RETURN Identity$

FNEND

Cmd_opc:SUB Cmd_opc(Set_cmd$)

COM /Instrument/ @Mwm

OUTPUT @Mwm;Set_cmd$

OUTPUT @Mwm;"*OPC?"

ENTER @Mwm;Opc_done$

SUBEND

3-38

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Programming

Example Programs

Example 5. Measure signal- to- noise ratio of each

WDM channel

This program measures signal-to- noise ratios on a WDM system. It

measures the ratio for each line using commands from the CALCulate3

subsystem.

Refer to the introduction to this section for a description of each sub-

routine that is contained in this program.

COM /Instrument/ @Mwm

ASSIGN @Mwm TO 720

DIM Key$[1]

ON ERROR GOTO Error_msg,

Set_ese

PRINT USING "37A,33A";"Multi-Wavelength Meter Identity is : ";FNIdentity$

ON TIMEOUT 7,5 CALL Err_mngmt

Cmd_opc("*RST")

OUTPUT @Mwm;":MEAS:ARR:POW:WAV?"

ENTER @Mwm USING "#,K";Nb_pt

ALLOCATE Current_wl(1:Nb_pt)

ENTER @Mwm USING "#,K";Current_wl(*)

OUTPUT @Mwm;":FETC:ARR:POW?"

ENTER @Mwm USING "#,K";Nb_pt

ALLOCATE Current_pwr(1:Nb_pt)

ENTER @Mwm USING "#,K";Current_pwr(*)

! Turn signal-to-noise ratio on

Cmd_opc(":CALC3:SNR:STAT ON")

Err_mngmt(":CALC3:SNR:STAT ON")

! Set first wavelength as noise reference

Cmd_opc(":CALC3:SNR:REF:WAV MIN")

Err_mngmt(":CALC3:SNR:REF:WAV MIN")

! Query number of data points

OUTPUT @Mwm;":CALC3:POIN?"

ENTER @Mwm USING "#,K";Nb_pt

ALLOCATE Snr_pwr(1:Nb_pt)

! Query signal-to-noise values

OUTPUT @Mwm;":CALC3:DATA? POW"

ENTER @Mwm;Snr_pwr(*)

OFF TIMEOUT

3-39

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Programming

Example Programs

FOR I=1 TO Nb_pt

PRINT USING "7A,2D,17A,M4D.3D,25A,S2D.2D,22A,2D.2D,3A";"Line : ";I;"

wavelength is : ";Current_wl(I)/1.0E-9;" nm, absolute level is : ";Current_pwr(I);" dBm,

with a SNR of : ";Snr_pwr(I);" dB"

NEXT I

STOP

Error_msg: !

PRINT "The program is aborted due to : ";ERRM$

END

Err_mngmt:SUB Err_mngmt(OPTIONAL Cmd_msg$)

COM /Instrument/ @Mwmt

DIM Err_msg$[255]

INTEGER Cme

CLEAR @Mwm

REPEAT !

OUTPUT @Mwm;"*ESR?"

ENTER @Mwm;Cme

OUTPUT @Mwm;":SYST:ERR?"

ENTER @Mwm;Err_msg$

IF NPAR>0 AND NOT POS(Err_msg$,"+0") THEN PRINT "This command

";Cmd_msg$;" makes the following error :"

IF NOT POS(Err_msg$,"+0") THEN PRINT Err_msg$

UNTIL NOT BIT(Cme,2) AND NOT BIT(Cme,4) AND NOT BIT(Cme,5) AND

POS(Err_msg$,"+0")

Subend:SUBEND

Set_ese:SUB Set_ese

COM /Instrument/ @Mwm

OUTPUT @Mwm;"*ESE ";IVAL("00110100",2)

SUBEND

Identity:DEF FNIdentity$;

COM /Instrument/ @Mwm

DIM Identity$[50]

Identity$=""

OUTPUT @Mwm;"*RST"

OUTPUT @Mwm;"*OPC?"

ENTER @Mwm;Opc_done

OUTPUT @Mwm;"*IDN?"

ENTER @Mwm;Identity$

RETURN Identity$

FNEND

Cmd_opc:SUB Cmd_opc(Set_cmd$)

COM /Instrument/ @Mwmd

OUTPUT @Mwm;Set_cmd$

OUTPUT @Mwm;"*OPC?"

ENTER @Mwm;Opc_done$

SUBEND

3-40

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Programming

Example Programs

Example 6. Increase a source’s wavelength accuracy

This examp le p rogram uses the Agilent 86120C to increase the abso-

lute wavelength accuracy of Agilent 8167A, 8168B, and 8168C Tunable

Laser Sources. Essentially, the Agilent 86120C’s accuracy is transferred

to the tunable laser source. The absolute accuracy of the tunable laser

source is increased from < 0.1 nm to < 0.003 nm which is the

Agilent 86120C’s absolute accuracy (at 1550 nm).

In order to run this program, the tunable laser source’s firmware must

support the automatic alignment command, WAVEACT.

The program uses the following measurement algorithm:

Identify and initialize the Agilent 86120C and tunable laser source

Ask user for desired wavelength

Set wavelength of tunable laser source

Turn tunable laser source’s output on

Enter loop

Measure wavelength

Compare wavelength to desired wavelength

Realign tunable laser source’s wavelength

Check if wavelength changed from last pass

Repeat until (delta wavelength < 0.0015 nm or wavelength is stable)

3-41

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Programming

Example Programs

COM Current_wl,Diff_wl.Target_wl,Previous_diff,Diff_diff

Current_wl=0

Diff_wl=0

Target_wl=0

Previous_diff=O

Diff_diff=0

ASSIGN @Tls TO 724

ASSIGN @Mwm TO 720

! Initialize instrument

DIM Identity$[50]

Identity$=""

OUTPUT @Tls;"*CLS"

OUTPUT @Tls;"*IDN?"

ENTER @TLS;identity$

PRINT "TLS IS A ";identity$

OUTPUT @Mwm;"*RST"

OUTPUT @Mwm;"*CLS"

OUTPUT @Mwm;"*IDN?"

ENTER @Mwm;Identity$

PRINT "MWM IS A ";identity$

! Ask user for desired wavelength

INPUT "What wavelength (nm)do you wish to have",Target_wl

Target_wl=Target_wl*1.OE-9

PRINT "the target wavelength is : ";Target_wl

! Set wavelength of tunable laser source

OUTPUT @Tls; ":WAVE ";VAL$(Target_wl)

OUTPUT @Tls; ":OUTP ON"

! Enter realignment loop

REPEAT

OUTPUT @Mwm;":MEAS:SCAL:POW:WAV?"

ENTER @Mwm;Current_wl

PRINT "The current wavelength is : ";VAL$(Current_wl)

Diff_wl=PROUND(ABS(Target_wl-Current_wl),-16)

PRINT "Diff between target & Current is (+ or -) : ";VAL$(Diff_wl)

OUTPUT @Tls;":WAVEACT ";VAL$(Current_wl)

Diff_diff=PROUND(ABS(Diff_wl-Previous_diff),-16)

PRINT "differential difference between two turn : ";VAL$(Diff_diff)

Previous_diff=Diff_wl

UNTIL (Diff_wl<1.5*1.0E-12) OR (Diff_diff=0)

END

3-42

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Programming

Lists of Commands

Table 3-10. Programming Commands (1 of 5)

Command

Description

Code

Codes: S indicates a standard SCPI command. I indicates an instrument specific command.

Common Commands

*CLS

*ESE

*ESR?

*IDN?

*OPC

*RCL

*RST

*SAV

*SRE

*STB

*TRG

*TST?

*WAI

Clears all event registers and the error queue.

Sets the bits in the standard-event status enable register.

Queries value standard-event status register.

Queries instrument model number and firmware version.

Sets operation complete bit of the standard-event status register.

Recalls a saved instrument state.

Resets instrument.

Saves an instrument state.

Sets bits in service-request enable register.

Queries value of status byte.

Triggers acquisition of measurement data.

Performs an instrument self test.

Causes instrument to finish processing current command before

continuing.

Measurement Instructions

:CONFigure

Configures instrument for wavelength, wavenumber,

frequency, power, and measurements.

:FETCh

Queries wavelength, wavenumber, frequency, power, and

measurements that have already been captured.

:MEASure

:READ

Configures, measures, and queries wavelength,

wavenumber, frequency, power, and measurements.

Measures and queries wavelength, wavenumber,

frequency, power, and measurements.

3-43

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Programming

Lists of Commands

Table 3-10. Programming Commands (2 of 5)

Command

Description

Code

Codes: S indicates a standard SCPI command. I indicates an instrument specific command.

CALCulate1 (CALC1) Subsystem

:CALCulate1:DATA?

Queries the uncorrected frequency-spectrum data of the

input signal.

:CALCulate1:TRANsform:FREQuency:POINts?

CALCulate2 (CALC2) Subsystem

:CALCulate2:DATA?

Sets and queries the number of points in the data set.

Queries the corrected frequency-spectrum data of the

input signal.

:CALCulate2:PEXCursion

:CALCulate2:POINts?

Sets the peak excursion limit.

Queries the number of points in the data set.

Sets the peak threshold limit.

:CALCulate2:PTHReshold

:CALCulate2:PWAVerage[:STATe]?

Places the instrument in the average-wavelength mode.

Data queries return the power-weighted average

frequency, wavelength, or wavenumber or total power.

:CALCulate2:WLIMit[:STATe]

Turns wavelength limiting on and off.

:CALCulate2:WLIMit:STARt:FREQuency

:CALCulate2:WLIMit:STARt[:WAVelength]

Sets the starting frequency for the wavelength limit range.

Sets the starting wavelength for the wavelength limit

range.

:CALCulate2:WLIMit:STARt:WNUMber

:CALCulate2:WLIMit:STOP:FREQuency

:CALCulate2:WLIMit:STOP[:WAVelength]

:CALCulate2:WLIMit:STOP:WNUMber

Sets the starting wavenumber for the wavelength limit

range.

Sets the stopping frequency for the wavelength limit

range.

Sets the stopping wavelength for the wavelength limit

range.

Sets the stopping wavenumber for the wavelength limit

range.

CALCulate3 (CALC3) Subsystem

:CALCulate3:ASNR:CLEar

:CALCulate3:ASNR:COUNt

Resets and restarts the signal-to-noise ratio averaging.

Sets the number of measurements to average the signal-

to-noise ratio.

:CALCulate3:ASNR:[:STATe]

:CALCulate3:DATA?

Turns signal-to-noise ratio averaging mode on and off.

Queries the data resulting from delta, drift, and signal-to-

noise measurements.

:CALCulate3:DELTa:POWer[:STATe]

Turns the delta power measurement mode on and off.

:CALCulate3:DELTa:REFerence:FREQuency

Selects the signal to be used as the reference for the

DELTa calculations.

:CALCulate3:DELTa:REFerence:POWer?

3-44

Queries the power level of the reference signal.

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Programming

Lists of Commands

Table 3-10. Programming Commands (3 of 5)

Command

Description

Code

Codes: S indicates a standard SCPI command. I indicates an instrument specific command.

:CALCulate3:DELTa:REFerence[:WAVelength]

Selects the signal to be used as the reference for the

DELTa calculations.

:CALCulate3:DELTa:REFerence:WNUMber

Selects the signal to be used as the reference for the

DELTa calculations.

:CALCulate3:DELTa:WAVelength[:STATe]

:CALCulate3:DELTa:WPOWer[:STATe]

Turns the delta wavelength measurement mode on and off.

Turns the delta wavelength and power measurement mode

on and off.

:CALCulate3:DRIFt:DIFFerence[:STATe]

:CALCulate3:DRIFt:MAXimum[:STATe]

:CALCulate3:DRIFt:MINimum[:STATe]

:CALCulate3:DRIFt:PRESet

Sets the drift calculation to subtract the minimum values

measured from the maximum values measured.

Sets the drift calculation to return the maximum power

(frequency) values measured.

Sets the drift calculation to return the minimum power

(frequency) values measured.

Turns off all the drift states for DIFFerence, MAXimum,

MINimum, and REFerence.

:CALCulate3:DRIFt:REFerence:RESet

:CALCulate3:DRIFt:REFerence[:STATe]

Places the current list of signals into the reference list.

Turns the drift state on and off so that CALC3:DATA? will

return the reference signal list.

:CALCulate3:DRIFt[:STATe]

Turns the drift measurement calculation on and off.

Turns the Fabry-Perot measurement mode on and off.

Queries the mean wavelength of the selected modes.

Queries the mean frequency of the selected modes.

Queries the mean wavenumber of the selected modes.

Queries the peak wavelength of the selected modes.

Queries the peak frequency of the selected modes.

Queries the peak wavenumber of the selected modes.

Queries the peak power of the selected modes.

:CALCulate3:FPERot[:STATe]

:CALCulate3:FPERot:MEAN:[WAVelength]?

:CALCulate3:FPERot:MEAN:FREQuency?

:CALCulate3:FPERot:MEAN:WNUMber?

:CALCulate3:FPERot:PEAK:[WAVelength]?

:CALCulate3:FPERot:PEAK:FREQuency?

:CALCulate3:FPERot:PEAK:WNUMber?

:CALCulate3:FPERot:PEAK:POWer?

:CALCulate3:FPERot:FWHM:[WAVelength]?

:CALCulate3:FPERot:FWHM:FREQuency?

:CALCulate3:FPERot:FWHM:WNUMber?

Queries full width half-max wavelength of selected modes.

Queries full width half-max frequency of selected modes.

Queries full width half-max wavenumber of selected

modes.

:CALCulate3:FPERot:MODE:SPACing:[WAVelengt Queries the mode spacing wavelength of the selected

h]? modes.

:CALCulate3:FPERot:MODE:SPACing:FREQuenc Queries the mode spacing frequency of the selected

y? modes.

:CALCulate3:FPERot:MODE:SPACing:WNUMbe Queries the mode spacing wavenumber of the selected

modes.

3-45

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Programming

Lists of Commands

Table 3-10. Programming Commands (4 of 5)

Command

Description

Code

Codes: S indicates a standard SCPI command. I indicates an instrument specific command.

:CALCulate3:FPERot:POWer:[WAVelength]?

:CALCulate3:FPERot:POWer:FREQuency?

:CALCulate3:FPERot:POWer:WNUMber?

:CALCulate3:FPERot:SIGMa:[WAVelength]?

:CALCulate3:FPERot:SIGMa:FREQuency?

:CALCulate3:FPERot:SIGMa:WNUMber?

:CALCulate3:POINts?

Queries the power wavelength of the selected modes.

Queries the power frequency of the selected modes.

Queries the power wavenumber of the selected modes.

Queries the sigma wavelength of the selected modes.

Queries the sigma frequency of the selected modes.

Queries the sigma wavenumber of the selected modes.

Queries the number of points in the data set.

:CALCulate3:PRESet

Turns off any CALCulate3 calculation that is on.

:CALCulate3:SNR:AUTO

Selects the internal or externally entered frequency value

for the noise measurement reference in the SNR

calculation.

:CALCulate3:SNR:REFerence:FREQuency

:CALCulate3:SNR:REFerence[:WAVelength]

:CALCulate3:SNR:REFerence:WNUMber

Sets the frequency used for the noise measurement

reference in the SNR calculation.

Sets the wavelength used for the noise measurement

reference in the SNR calculation.

Sets the wave number used for the noise measurement

reference in the SNR calculation.

:CALCulate3:SNR[:STATe]

DISPlay Subsystem

Turns the SNR calculation on and off.

:DISPlay:MARKer:MAXimum

Sets the marker to the signal with the largest power.

:DISPlay:MARKer:MAXimum:LEFT

Moves marker to signal with the next lower wavelength or

frequency.

:DISPlay:MARKer:MAXimum:NEXT

Moves the marker to the signal with the closest power

level just below the power level of the signal at the current

marker position.

:DISPlay:MARKer:MAXimum:PREVious

Moves the marker to the signal with the closest power

level just above the power level of the signal at the current

marker position.

:DISPlay:MARKer:MAXimum:RIGHt

:DISPlay[:WINDow]:GRAPhics:STATe

Moves marker to the next higher wavelength or frequency.

Turns the instrument display of the power bars on and off.

HCOPy Subsystem

:HCOPy:IMMediate

SENSe Subsystem

Starts a printout.

:SENSe:CORRection:DEVice

Configures wavelength measurements for narrowband or

wideband devices.

3-46

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Programming

Lists of Commands

Table 3-10. Programming Commands (5 of 5)

Command

Description

Code

Codes: S indicates a standard SCPI command. I indicates an instrument specific command.

:SENSe:CORRection:ELEVation

Sets the elevation value used by the instrument to

compensate for air dispersion.

:SENSe:CORRection:OFFSet:MAGNitude

:SENSe:CORRection:MEDium

Sets the power offset value used by the instrument.

Sets the instrument to return the wavelength reading in a

vacuum when the parameter is on. Parameters are VAC

and AIR.

:SENSe:DATA?

Queries the time domain samples of the input signal.

STATus Subsystem

:STATus:{OPERation | QUEStionable}:CONDitio Returns the value for the condition register for the node.

:STATus:{OPERation | QUEStionable}:EVENt?

:STATus:{OPERation | QUEStionable}:ENABle

Returns the value of the event register for the node.

Sets the enable register.

:STATus:{OPERation | QUEStionable}:PTRansit

ion

Sets the positive transition filter register.

:STATus:{OPERation | QUEStionable}:NTRansit Sets the negative transition filter register.

ion

:STATus:PRESet

Presets the enable registers for all status nodes.

SYSTem Subsystem

:SYSTem:ERRor?

Queries an error from the error queue.

:SYSTem:HELP:HEADers?

Queries an ASCII listing of all Agilent 86120C remote

commands.

:SYSTem:PRESet

:SYSTem:VERSion

Performs the equivalent of a front-panel PRESET key

press.

Queries the version of SCPI with which this instrument is

compliant.

TRIGger Subsystem

:ABORt

Stops the current measurement sequence.

:INITiate:IMMediate

Places the instrument into the initiated state and initiates

a new measurement sequence.

:INITiate:CONTinuous

Sets the instrument for single or continuous

measurement.

UNIT Subsystem

:UNIT[:POWer]

Sets the power units to watts (linear) or dBm (logarithmic).

3-47

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Programming

Lists of Commands

Table 3-11. Keys Versus Commands (1 of 2)

Key

Equivalent Command

:CALCulate3:DELTa:POWer[:STATe]

:CALCulate3:DELTa:WAVelength[:STATe]

:CALCulate3:DELTa:WPOWer[:STATe]

See DRIFT, S/N, and FP TEST

:CALCulate3:SNR:AUTO ON

∆ PWR

∆ WL

∆ WL/PWR

Appl's

AUTO

Avg WL

BAR OFF

BAR ON

BROAD

CAL

:CALCulate2:PWAVerage[:STATe]

:DISPlay[:WINDow]:GRAPhics:STATe

:SENSe:CORRection:DEVice BROad

See ELEV, PWR OFS, STD AIR, and VACUUM

:MEASure:ARRay:POWer:WNUMber

:INITiate:CONTinuous ON

CM-1

Cont

DBM

:UNIT:POWer

DEVICE

DRIFT

:SENSe:CORRection:DEVice

:CALCulate3:DRIFt[:STATe]

ELEV

:SENSe:CORRection:ELEVation

State dependent

EXIT

FAST

See UPDATE

FP TEST

GPIB

:CALCulate3:FPERot[:STATe]

none

List by Power

List by WL

MAX-MIN

:CONFigure:ARRay:POWer

:MEASure:ARRay:POWer:WAVelength

:CALCulate3:DRIFt:MINimum[:STATe] and :CALCulate3:DRIFt:MAXimum[:STATe]

:UNIT:POWer

NARROW

NEXT PK

NEXT WL

:SENSe:CORRection:DEVice NARRow

:DISPlay:MARKer:MAXimum:NEXT

:DISPlay:MARKer:MAXimum:RIGHt

:MEASure:ARRay:POWer:WAVelength

See UPDATE

NORMAL

OFF

:CALCulate3:DELTa:POWer[:STATe]

:DISPlay:MARKer:MAXimum

PEAK

3-48

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Programming

Lists of Commands

Table 3-11. Keys Versus Commands (2 of 2)

Key

Equivalent Command

Peak WL

PK EXC

PK THLD

POWER

Preset

See NEXT PK, NEXT WL, PEAK, PREV PK, and PREV WL

:CALCulate2:PEXCursion

:CALCulate2:PTHReshold

:UNIT:POWer

:SYSTem:PRESet

PREV PK

PREV WL

:DISPlay:MARKer:MAXimum:PREVious

:DISPlay:MARKer:MAXimum:LEFT

:HCOPy:IMMediate

PWR BAR

PWR OFF

RESET

See BAR ON and BAR OFF

:SENSe:CORRection:OFFSet:MAGNitude

:CALCulate3:DRIFt:REFerence:RESet

:CALCulate3:SNR:STATe

S/N

S/N AVG

SELECT

Setup

:CALCulate3:ASNR:STATe

:CONFigure:POWer

See CAL, UNITS, and UPDATE

:INITiate:CONTinuous OFF

Single

START WL

STOP WL

STD AIR

THRSHLD

THZ

:CALCulate2:WLIMit:STARt

:CALCulate2:WLIMit:STOP

:SENSe:CORRection:MEDium AIR

See PK EXC and PK THLD

:MEASure:ARRay:POWer:FREQuency

:UNIT:POWer

UNITS

UPDATE

USER

Measurement Instructions and :CALCulate1:TRANsform:FREQuency:POINts

:CALCulate3:SNR:AUTO OFF

:CALCulate3:SNR:REFerence[:WAVelength]

UNIT:POWer

USER WL

VACUUM

:SENSe:CORRection:MEDium VACuum

See CM, NM, and THZ

WL REF

See AUTO, USER, and USER WL

3-49

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Programming

Lists of Commands

3-50

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Common Commands 4- 3

Measurement Instructions 4-15

CALCulate1 Subsystem 4- 25

CALCulate2 Subsystem 4- 31

CALCulate3 Subsystem 4- 44

CONFigure Measurement Instruction 4- 74

DISPlay Subsystem 4- 75

FETCh Measurement Instruction 4- 79

HCOPy Subsystem 4- 80

MEASure Measurement Instruction 4- 81

READ Measurement Instruction 4- 82

SENSe Subsystem 4- 83

STATus Subsystem 4- 90

SYSTem Subsystem 4- 97

TRIGger Subsystem 4- 103

UNIT Subsystem 4-107

Programming Commands

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Programming Commands

This chap ter is the reference for all Agilent 86120C programming com-

mands. Commands are organized by subsystem.

Table 4-12. Notation Conventions and Definitions

Convention

Description

< >

Angle brackets indicate values entered by the programmer.

”Or” indicates a choice of one element from a list.

[ ]

Square brackets indicate that the enclosed items are optional.

{ }

When several items are enclosed by braces, one, and only one of these

elements must be selected.

<real>

An ASCII string representing an integer. This is defined by the IEEE 488.2

<NR1> format.

An ASCII string representing a real number. This is defined by the IEEE 488.2

<NR2> or <NRf> formats.

4-2

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Programming Commands

Common Commands

Common commands are defined by the IEEE 488.2 standard. They

control generic device functions which could be common among many

different types of instruments. Common commands can be received

and p rocessed by the instrument whether they are sent over the GPIB

as separate program messages or within other program messages.

*CLS

The *CLS (clear status) command clears all the event status registers

summarized in the status byte register.

*CLS

Syntax

Description

With the exception of the output queue, all queues that are summa-

rized in the status byte register are emptied. The error queue is also

emptied. Neither the event status enable register, nor the service

request enable register are affected by this command.

After the *CLS command, the instrument is left in the idle state. The

command does not alter the instrument setting. *OPC and *OPC?

actions are cancelled.

This command cannot be issued as a query.

*ESE

The *ESE (event status enable) command sets the bits in the event sta-

tus enable register and enables the corresponding bits in the event sta-

tus register.

*ESE <integer>

*ESE?

Syntax

4-3

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Programming Commands

Common Commands

<integer> is a mask from 0 to 255.

Description

The event status enable register contains a mask value for the bits to

be enabled in the event status register. A bit set to one (1) in the

event status enable register enables the corresp onding bit in the event

status register to set the event summary bit in the status byte register.

A zero (0) disables the bit. Refer to the following table for information

about the event status enable register bits, bit weights, and what each

bit masks. The event status enable register is cleared at power- on. The

*RST and *CLS commands do not change the register. The *ESE? query

returns the value of the event status enable register.

Table 4-13. Event Status Enable Register

Bit^a

Bit Weight

Enables

128

PON – Power On

Not Used

CME – Command Error

EXE – Execution Error

DDE – Device Dependent Error

QYE – Query Error

Not Used

OPC – Operation Complete

a. A high enables the event status register bit.

Query Response

Example

<integer> is a mask from 0 to 255.

OUTPUT 720;”*ESE 32”

In this examp le, the *ESE 32 command enables CME (event summary

bit) bit 5 of the event status enable register. Therefore, when an incor-

rect programming command is received, the CME (command error bit)

in the status byte register is set.

4-4

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Programming Commands

Common Commands

*ESR?

The *ESR (event status register) query returns the value of the event

status register.

*ESR?

Syntax

Description

When you read the standard event status register, the value returned

is the total of the bit weights of all of the bits that are set to one at

the time you read the byte. The following table shows each bit in the

event status register and its bit weight. The register is cleared when it

is read.

Table 4-14. Standard Event Status Register

Bit

Bit Weight

Condition

128

PON – Power On

Not Used

CME – Command Error

EXE – Execution Error

DDE – Device Dependent Error

QYE – Query Error

Not Used

OPC – Operation Complete

Query Response

Example

<integer> ranges from 0 to 255.

OUTPUT 720;”*ESR?”

ENTER 720;Event

PRINT Event

4-5

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Programming Commands

Common Commands

*IDN?

The *IDN? (identification number) query returns a string value which

identifies the instrument type and firmware version.

*IDN?

Syntax

Description

An *IDN? query must be the last query in a p rogram message. Any

queries after the *IDN? query in a p rogram message are ignored.

The maximum length of the identification string is 50 bytes.

Query Response

Example

The following identification string is returned. The third entry is the

instrument’s serial number. The last entry in the string is the firmware

version number; this value may vary between instruments.

Agilent 86120C, USaaaabbbb, 1.000

DIM Id$[50]

OUTPUT 720;”*IDN?”

ENTER 720;Id$

PRINT Id$

4-6

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Programming Commands

Common Commands

*OPC

The *OPC (operation complete) command sets the operation complete

bit in the event status register when all p ending device op erations

have finished.

*OPC

*OPC?

Syntax

Description

The *OPC? query p laces an ASCII “1” in the outp ut queue when all

pending device operations have finished.

This command is useful when the computer is sending commands to

other instruments. The comp uter can p oll the event status register to

check when the Agilent 86120C has comp leted the op eration. Use the

*OPC? query to ensure all operations have completed before continuing

the p rogram. By following a command with an *OPC? query and an

ENTER statement, the p rogram will p ause until the resp onse (ASCII

“1”) is returned by the instrument.

Be sure the comp uter’s timeout limit is at least two seconds, since

some of the Agilent 86120C commands take approximately one second

to complete.

Query Response

Example

OUTPUT 720;”*OPC?”

ENTER 720;Op$

*RCL

This command recalls a saved instrument state.

Syntax

*RCL <integer>

<integer> range is 1 to 4.

Description

For a descrip tion of an instrument state, see *SAV command.

4-7

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Programming Commands

Common Commands

*RST

The *RST (reset) command returns the Agilent 86120C to a known

condition.

*RST

Syntax

Description

For a listing of reset conditions, refer to the following table. This com-

mand cannot be issued as a query. Since this command p laces the

instrument in single measurement acquisition mode, any current data

is marked as invalid and a measurement query such as :FETCh?

results in error number –230, “Data corrup t or stale”. You must ini-

tiate a new sweep with :INIT:IMM before you can use the :FETCh com-

mand.

Table 4-15. Conditions Set by *RST Reset (1 of 2)

Item

Setting

Display mode

single wavelength

1270 nm

1650 nm

off

Start wavelength

Stop wavelength

Graphical display

Measurement acquisition

Wavelength calibration

Elevation correction value

Wavelength units

Amplitude units

single

vacuum

0 meters

dBm

Power offset

0 dB

Peak threshold

10 dB

Peak excursion

15 dB

Measurement speed

normal

4-8

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Programming Commands

Common Commands

Table 4-15. Conditions Set by *RST Reset (2 of 2)

Item

Setting

15,047

Number of uncorrected data points

Delta Measurements:

∆ power

off

∆ wavelength

off

∆ wavelength and power

reference signal position

Drift measurements

Signal-to-Noise Measurements:

measurement

1270 nm

off

wavelength reference

reference (user) wavelength

number of averages (count)

GPIB address

auto

1550 nm in vacuum

100

not affected

Power-bar display

*SAV

This command saves an instrument state.

Syntax

*SAV <integer>

<integer> range is 1 to 4.

Description

The following constitutes an instrument state: single/continuous mea-

surement mode, power bar on/off, vacuum/STD air mode, normal/fast

up date, list by WL, list by Pwr, p eak, or avg disp lay mode, frequency

units, p ower units, elevation, p eak excursion, p eak threshold, p ower

4-9

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Programming Commands

Common Commands

offset, signal- to- noise auto mode on/off, wavelength limit on/off, wave-

length limit start, wavelength limit stop, and signal- to- noise average

count.

*SRE

The *SRE (service request enable) command sets the bits in the service

request enable register.

*SRE <integer>

*SRE?

Syntax

<integer> is defined as an integer mask from 0 to 255.

Description

The service request enable register contains a mask value for the bits

to be enabled in the status byte register. A bit set to one in the service

request enable register enables the corresponding bit in the status byte

lowing table lists the bits in the service request enable register and

what they mask.

The service request enable register is cleared when the instrument is

turned on. The *RST and *CLS commands do not change the register.

The *SRE? query returns the value of the service request enable regis-

ter.

Table 4-16. Service Request Enable Register

Bit^a

Bit Weight

Enables

128

Not Used

Event Status Bit (ESB)

Message Available (MAV)

Not Used

Error queue status

Not Used

a. High enables the status byte register bit.

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Programming Commands

Common Commands

Query Response

Example

<integer> from 0 to 63 or from 128 to 191.

OUTPUT 720;”*SRE 32”

In this example, the command enables ESB (event summary) bit 5 in

the status byte register to generate a service request.

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Programming Commands

Common Commands

*STB?

The *STB (status byte) query returns the current value of the instru-

ment’s status byte.

*STB?

Syntax

Description

The master summary status (MSS) bit 6 indicates whether or not the

device has at least one reason for requesting service. When you read

the status byte register, the value returned is the total of the bit

weights of all of the bits set to one at the time you read the byte. The

following table shows each bit in the status byte register and its bit

weight. The *STB? query does not affect the contents of the status byte

Table 4-17. Status Byte Register

Bit

Bit Weight

Condition

128

Not Used

Master Summary Status (MSS)

Event Status Bit (ESB)

Message Available (MAV)

Not Used

Error queue status

Not Used

Query Response

Example

<integer> from 0 to 255.

OUTPUT 720;”*STB?”

ENTER 720;Value

PRINT Value

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Programming Commands

Common Commands

*TRG

The *TRG (trigger) command is identical to the group execute trigger

(GET) message or RUN command.

*TRG

Syntax

Description

This command acquires data according to the current settings. This

command cannot be issued as a query. If a measurement is already in

p rogress, a trigger is ignored, and an error is generated.

Example

The following example starts the data acquisition according to the cur-

rent settings.

OUTPUT 720;”*TRG”

*TST?

The *TST (test) query starts a self- test on the instrument.

*TST?

Syntax

Description

The result of the test is p laced in the outp ut queue. A zero indicates

the test p assed and a non- zero value indicates the test failed. The

instrument will initiate a measurement and check for any hardware

errors after the measurement is comp lete.

Query Response

Example

OUTPUT 720;”*TST?”

ENTER 720;Result

PRINT Result

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Programming Commands

Common Commands

*WAI

The *WAI command prevents the instrument from executing any fur-

ther commands until the current command has finished executing.

*WAI

Syntax

Description

All p ending op erations are comp leted during the wait p eriod. This

command cannot be issued as a query.

4-14

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Programming Commands

Measurement Instructions

Use the measurement instructions documented in this section to per-

form measurements and return the desired results to the comp uter.

Four basic measurement instructions are used: CONFigure, FETCh,

READ, and MEASure. Because the command trees for each of these

four basic measurement instructions are identical, only the MEASure

tree is documented.

To p erform a measurement, ap p end to the measurement instruction a

POWer or LENGth function. The POWer functions select power, fre-

quency, wavelength, or wave number measurements.

When the :SCALar command is used, data for a single measurement

value is returned. When the :ARRay command is used, multip le data

values are returned.

The MEASure measurement instruction always acquires new measure-

ment data. In order to obtain both wavelength and p ower values from

the same measurement data, use two FETCh commands. This is shown

in the following p rogram fragment:

OUTPUT 720;”:INIT:CONT OFF;”

OUTPUT 720;”:CONF:ARR:POW MAX”

OUTPUT 720;”:INIT:IMM”

OUTPUT 720;”:FETC:ARR:POW?”

ENTER 720:powers$

OUTPUT 720;”:FETC:ARR:POW:WAV?”

ENTER 720:wavelengths$

In the examp le above, the data in the p ower and wavelength arrays

are returned in the same order so that p owers can be matched to

wavelengths. You can also send a MEASure command followed by a

FETCh command.

4-15

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Programming Commands

Measurement Instructions

The commands in this subsystem have the following command hierar-

chy:

{:MEASure | :READ[?] | :FETCh[?] | :CONFigure[?]}

{:ARRay | [:SCALar] }

:POWer[?]

:FREQuency[?]

:WAVelength[?]

:WNUMber[?]

4-16

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Programming Commands

Measurement Instructions

MEASure{:ARRay | [:SCALar]} :POWer?

Returns amplitude values.

Syntax

:POWer? [<expected_value>[,<resolution>]]

Used With

<expected_value>

SCALar

ARRay

optional

ignored

Description

When used with a :SCALar command, a single value is returned. The

disp lay is p laced in the single- wavelength mode, and the marker is

p laced on the signal having a p ower level that is closest to the

<expected_value> p arameter.

When used with an :ARRay command, an array of amp litudes is

returned. The disp lay is p laced in the list- by- p ower mode.

Returned values are in the current p ower units. Wavelength units are

not affected.

CONFigure command

When this function is used with the CONFigure command, the query question

mark character “?” must not be included in the string. However, the FETCh, READ,

and MEASure command are queries and require the question mark. Refer to the

examples for this command.

<expected_value> MAXimum

Displays the highest power signal

Constants

MINimum

Displays the lowest power signal

DEFault

Displays the signal at the current marker position

4-17

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Programming Commands

Measurement Instructions

Examples

:CONF:ARR:POW

:FETC:ARR:POW?

:READ:ARR:POW?

:MEAS:ARR:POW?

:CONF:SCAL:POW -10 dBm

:FETC:SCAL:POW? MAX

:READ:SCAL:POW? MIN

:MEAS:SCAL:POW? DEF

Query Response

The following line is an examp le of a returned string when

:MEAS:SCAL:POW? MAX is sent:

-5.88346500E+000

If six laser lines are located and :MEAS:ARR:POW? is sent, the follow-

ing string could be returned. Notice that the first returned number

indicates the number of laser- line values returned in the query. The

measurement units are in dBm.

6,-1.37444400E+001,-1.10996100E+001,-9.62396600E+000,

-7.94024500E+000,-7.01303200E+000,-1.04536200E+001

4-18

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Programming Commands

Measurement Instructions

MEASure{:ARRay | [:SCALar]} :POWer:FREQuen-

cy?

Returns frequency values.

Syntax

:POWer:FREQuency? [<expected_value>[,<resolution>]]

Used With

<expected_value>

SCALar

ARRay

optional

ignored^a

optional

a. Although ignored, this argument must be present if the resolution argument is specified.

Description

When used with a :SCALar command, a single value is returned. The

disp lay is p laced in the single- wavelength mode, and the marker is

p laced on the signal having a frequency that is closest to the

<expected_value> p arameter. Default units for <expected_value>

p arameter are in Hz. When used with an :ARRay command, an array

of frequencies is returned. The disp lay is p laced in the list- by-wave-

length mode.

The <resolution> parameter sets the resolution of the measurement. It

is a unitless number whose value will be limited to either 0.01 or

0.001 (whichever is closer). MAXimum resolution is equivalent to the

FAST measurement update mode. MINimum resolution is equivalent to

the NORMAL measurement up date mode.

Returned values are in Hz (disp lay is in THz). Power units are not

affected.

CONFigure command

When this function is used with the CONFigure command, the query question

mark character “?” must not be included in the string. However, the FETCh, READ,

and MEASure command are queries and require the question mark. Refer to the

examples for this command.

<expected_value> MAXimum

The highest frequency signal

The lowest frequency signal

Constants

MINimum

4-19

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Programming Commands

Measurement Instructions

DEFault

The current marker position

Constants

MAXimum

MINimum

DEFault

0.01 resolution (fast update)

0.001 resolution (normal)

Current resolution

Examples

:CONF:ARR:POW:FREQ DEF, MIN

:FETC:ARR:POW:FREQ? DEF, MAX

:READ:ARR:POW:FREQ?

:MEAS:ARR:POW:FREQ?

:CONF:SCAL:POW:FREQ 230.8THZ, MAX

:FETC:SCAL:POW:FREQ? 230.8THZ, MIN

:READ:SCAL:POW:FREQ? 230.8THZ

:MEAS:SCAL:POW:FREQ? 230.8THZ

Query Response

The following line is an examp le of a returned string when

:MEAS:SCAL:POW:FREQ? MAX is sent:

+1.94055176E+014

If six laser lines are located and :MEAS:ARR:POW:FREQ? is sent, the

following string is an examp le of the returned data. Notice that the

first returned number indicates the number of laser- line values

returned in the query.

6,+1.94055100E+014,+1.93854100E+014,+1.93653000E+014,+1.93452000E+014,+1.93250900E+0

14,+1.93050000E+014

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Programming Commands

Measurement Instructions

MEASure{:ARRay | [:SCALar]} :POWer:WAVe-

length?

Returns wavelength values.

:POWer:WAVelength? [<expected_value>[,<resolution>]]

Syntax

Used With

<expected_value>

SCALar

ARRay

optional

ignored^a

optional

a. Although ignored, this argument must be present if the resolution argument is specified.

Description

When used with a :SCALar command, a single value is returned. The

disp lay is p laced in the single- wavelength mode, and the marker is

p laced on the signal having a wavelength that is closest to the

<expected_value> p arameter. Default units for <expected_value>

parameter are in meters.

When used with an :ARRay command, an array of wavelengths is

returned. The disp lay is p laced in the list- by- wavelength mode.

The <resolution> parameter sets the resolution of the measurement. It

is a unitless number whose value will be limited to either 0.01 or

0.001 (whichever is closer).

Returned values are in meters. Displayed units are nanometers. Power

units are not affected.

CONFigure command

When this function is used with the CONFigure command, the query question

mark character “?” must not be included in the string. However, the FETCh, READ,

and MEASure command are queries and require the question mark. Refer to the

examples for this command.

<expected_value> MAXimum

The highest wavelength signal

The lowest wavelength signal

The current marker position

Constants

MINimum

DEFault

4-21

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Programming Commands

Measurement Instructions

Constants

MAXimum

MINimum

DEFault

0.01 resolution (fast update)

0.001 resolution (normal)

Current resolution

Examples

:CONF:ARR:POW:WAV DEF, MAX

:FETC:ARR:POW:WAV? DEF, MIN

:READ:ARR:POW:WAV?

:MEAS:ARR:POW:WAV?

:CONF:SCAL:POW:WAV 1300NM, MAX

:FETC:SCAL:POW:WAV? 1300NM, MIN

:READ:SCAL:POW:WAV? 1300NM

:MEAS:SCAL:POW:WAV? 1300NM

Query Response

The following line is an examp le of a returned string when

:MEAS:SCAL:POW:WAV? MAX is sent:

+1.5529258E-006

If six laser lines are located and :MEAS:ARR:POW:WAV? is sent, the

following string could be returned. Notice that the first returned num-

ber indicates the number of laser- line values returned in the query.

6,+1.54488100E-006,+1.54648400E-006,+1.54809000E-006,+1.54969900E-006,+1.55131100E-

006,+1.55292600E-006

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Programming Commands

Measurement Instructions

MEASure{:ARRay | [:SCALar]} :POWer:WNUMber?

Returns a wave number value.

Syntax

:POWer:WNUMber? [<expected_value>[,<resolution>]]

Used With

<expected_value>

SCALar

ARRay

optional

ignored^a

optional

a. Although ignored, this argument must be present if the resolution argument is specified.

Description

When used with a :SCALar command, a single value is returned. The

disp lay is p laced in the single- wavelength mode, and the marker is

p laced on the signal having a wave number that is closest to the

<expected_value> p arameter. Default units for <expected_value>

parameter are in m^–1.

When used with an :ARRay command, an array of wave number is

returned. The disp lay is p laced in the list- by- wavelength mode.

The <resolution> parameter sets the resolution of the measurement. It

is a unitless number whose value will be limited to either 0.01 or

0.001 (whichever is closer).

Returned values are in inverse meters. Displayed units are inverse

centimeters. Power units are not affected.

CONFigure command

When this function is used with the CONFigure command, the query question

mark character “?” must not be included in the string. However, the FETCh, READ,

and MEASure command are queries and require the question mark. Refer to the

examples for this command.

<expected_value> MAXimum

The laser line having the largest wave number

The laser line having the smallest wave number

The current marker position

Constants

MINimum

DEFault

4-23

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Programming Commands

Measurement Instructions

Constants

MAXimum

MINimum

DEFault

0.01 resolution (fast update)

0.001 resolution (normal)

Current resolution

Examples

:CONF:ARR:POW:WNUM DEF, MAX

:FETC:ARR:POW:WNUM? DEF, MIN

:READ:ARR:POW:WNUM?

:MEAS:ARR:POW:WNUM?

:CONF:SCAL:POW:WNUM 6451, MAX

:FETC:SCAL:POW:WNUM? 6451, MIN

:READ:SCAL:POW:WNUM? 6451

:MEAS:SCAL:POW:WNUM? 6451

Query Response

If the :MEAS:SCAL:POW:WNUM? 6451 command is sent, and a 1550

nm laser line is p resent, the following resp onse would be returned to

the computer:

+6.45286262E+005

Notice that the returned units are m^–1. If six laser lines are measured

and :MEAS:ARR:POW:WNUM? is sent, the following resp onse is

returned. Notice that the first returned number indicates the number

of laser- line values returned in the query.

6,+6.47298400E+005,+6.46627900E+005,+6.45957000E+005,+6.45286300E+005,+6.44615600E+0

05,+6.43945300E+005

4-24

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Programming Commands

CALCulate1 Subsystem

Use the CALCulate1 commands to query uncorrected frequency- sp ec-

trum data. In NORMAL measurement up date mode, 15,047 values are

returned. If the Agilent 86120C is set for FAST measurement up date

mode (low resolution), 7,525 values are returned.

The commands in this subsystem have the following command hierar-

chy:

:CALCulate1

:DATA?

:TRANsform

:FREQuency

:POINts

4-25

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Programming Commands

CALCulate1 Subsystem

DATA?

Queries uncorrected frequency- sp ectrum data of the inp ut laser line.

Syntax

:CALCulate1:DATA?

Attribute

Summary

Preset State: not affected

SCPI Compliance: standard

Query Only

Description

The returned values are proportional to squared Watts (linear) units.

No amp litude or frequency correction is ap p lied to the values. To

obtain the logarithmic (dB) result, normalize the returned values by

the largest value, then take five times the logarithm of the normalized

values.

Be p rep ared to p rocess a large amount of data when this query is

sent. The amount of data returned depends on the measurement

up date state of the instrument which can be set using the

:CALCulate1:TRANsform:FREQuency:POINts command or the resolution

argument of an instrument function. Refer to “Measurement Instruc-

tions” on page 4- 15.

When NORMAL measurement update is sp ecified, over 250 kilobytes of

data (15,047 values) can be returned to the comp uter. When

FAST

measurement update is specified, over 125 kilobytes of data (7,525 val-

ues) can be returned.

The following string is a typical example of the first few returned val-

ues:

+4.02646500E+001,+6.78125100E+001,+6.17986600E+001,+4.26768200E+001,+4.80245300E+00

1,+3.10491300E+001,+1.13409400E+001,+5.07832500E+001,+2.77746200E+001,+3.89150500E+0

01,+3.50217600E+001,+7.34649800E-001,+5.64983800E+000,

Notice that only measurement values are returned to the comp uter.

There is no first value that indicates the number of values contained

in the string as there is, for examp le, with the FETCh, READ, and

MEASure commands. Use the :CALCulate1:TRANsform:FRE-

Quency:POINTs command to query the number of p oints the

:CALC1:DATA? returns.

4-26

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Programming Commands

CALCulate1 Subsystem

When NORMAL measurement mode is selected, the uncorrected fre-

quency domain data consists of 64K values. Only the frequency domain

data corresp onding to 1270–1650 wavelength (in vacuum) is returned

(15,047 values). In FAST measurement mode, the data consists of 32K

values of which 7,525 values are returned.

In NORMAL measurement mode, the frequency sp acing between values

is uniform and is equal to 3.613378 GHz. Note that the sp acing

between values is not uniform in wavelength units. The values

returned are in ascending optical frequency.

The first value of the uncorrected frequency data corresp onds to an

optical frequency of 181.6915 THz (1650.008 nm). The last value of the

uncorrected frequency data corresp onds to an op tical frequency of

236.0584 THz (1269.993 nm). For examp le, a laser line p eak located

at the 3,000th returned value has an op tical frequency of:

frequency = 181,6915 THz + 2, 999(3,613378 GHz)

= 192,5280 THz

or, 1557.137 nm (in vacuum).

When FAST measurement mode is selected, the frequency spacing

between elements is uniform and is equal to 7.226756 GHz. Note the

spacing between values is not uniform in wavelength units. The values

returned are in ascending optical frequency. Only the frequency

domain data corresponding to 1270–1650 wavelength (in vacuum) is

returned (7,525 values). The first value of the uncorrected frequency

data corresponds to an optical frequency of 181.6879 THz (1650.041

nm). The last value of the uncorrected frequency data corresp onds to

an optical frequency of 236.0620 THz (1269.974 nm). For example, a

laser line peak located at the 1500th returned value has an optical fre-

quency of:

frequency = 181,6879 THz + 1, 499(7,226756 GHz)

= 192,5208 THz

or, 1557.195 nm (in vacuum).

If your program is aborted or interrupted after sending this query, the

Agilent 86120C continues to p rocess the data but does not p lace it in

the outp ut buffer. Because of the amount of data p rocessed, the

instrument will not respond to any new commands in its inp ut buffer

for up to 20 seconds.

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Programming Commands

CALCulate1 Subsystem

This query will generate a “Settings conflict” error if the instrument is

in the signal- to-noise average ap p lication.

4-28

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Programming Commands

CALCulate1 Subsystem

TRANsform:FREQuency:POINts

Sets the size of the fast Fourier transform (FFT) p erformed by the

instrument.

Syntax

:CALCulate1:TRANsform:FREQuency:POINts{?| {<integer> | MINimum | MAXimum}}

<integer> Sets FFT size. Must be either 15,047 or 7,525. Other values

result in an error.

Constant

Description

7,525

MINimum

MAXimum

15,047

Attribute

Summary

Non- sequential command

Preset State: array size set to 15,047

*RST State: 15,047

SCPI Comp liance: instrument sp ecific

Description

A NORMAL up dated disp lay corresp onds to an FFT size of 15,047. A

FAST up dated disp lay corresp onds to an FFT size of 7,525. These val-

ues are a subset of the uncorrected- data buffer shown in the figure

that is located in “Making Measurements” on page 3-5. Changing the

number of points causes the instrument to reprocess the current set of

data.

The query form of the command returns the number of points in the

data set. This is the number of measurement points that will be

returned by the CALC1:DATA? query.

Non-sequential command

Always use an *OPC? query or a *WAI command to ensure that this command has

the time to complete before sending any more commands to the instrument. Refer

to “Always force the Agilent 86120C to wait for non-sequential commands” on

page 3-12 for more information.

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Programming Commands

CALCulate1 Subsystem

Query Response

For normal update:

+15,047

For fast update:

+7,525

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Programming Commands

CALCulate2 Subsystem

Use the CALCulate2 commands to query corrected values frequency-

spectrum data.

The commands in this subsystem have the following command hierar-

chy:

:CALCulate2

:DATA?

:PEXCursion

:POINts?

:PTHReshold

:PWAVerage

[:STATe]

:WLIMit

[:STATe]

:STARt

:FREQuency

[:WAVelength]

:WNUMber

:STOP

:FREQuency

[:WAVelength]

:WNUMber

4-31

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Programming Commands

CALCulate2 Subsystem

DATA?

Queries the corrected peak data of the input laser line.

Syntax

:CALCulate2:DATA? {FREQuency | POWer | WAVelength | WNUMber}

Constant

Description

FREQuency

Queries the array of laser-line frequencies after the peak search is

completed. If :CALC2:PWAV:STAT is on, the power-weighted

average frequency is returned.

POWer

Queries the array of laser-line powers after the peak search is

completed. If :CALC2:PWAV:STAT is on, the total input power is

returned.

WAVelength

WNUMber

Queries the array of laser-line wavelengths after the peak search

is completed. If :CALC2:PWAV:STAT is on, the power-weighted

average wavelength is returned.

Queries the array of laser-line wave numbers after the peak

search is completed. If :CALC2:PWAV:STAT is on, the power-

weighted average wave number is returned.

Attribute

Summary

Preset State: not affected

SCPI Compliance: standard

Query Only

Description

Use the CALC2:POIN? query to determine the number of points the

CALC2:DATA? query will return. The following string is a typical

example of the first few returned values when WAVelength is specified:

+1.54488600E-006,+1.54649100E-006,+1.54808300E-006,+1.54969600E-006,+1.55131200E-

006,+1.55293000E-006

This next string resulted by sp ecifying the WNUMber argument:

+6.47296600E+005,+6.46625000E+005,+6.45959900E+005,+6.45287500E+005,+6.44615500E+00

5,+6.43943900E+005

Notice that only measurement values are returned to the comp uter.

There is no first value that indicates the number of values contained

in the string as there is, for examp le, with the FETCh, READ, and

MEASure commands.

4-32

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Programming Commands

CALCulate2 Subsystem

When there is no input signal, the POWer query returns –200 dBm; the

WAVelength query returns 100 nm (1.0E–7).

PEXCursion

Sets the peak excursion limit used by the Agilent 86120C to determine

valid laser line peaks.

Syntax

:CALCulate2:PEXCursion{?| {<integer> | MINimum | MAXimum | DEFault}}

<integer> represents logarithmic units in dB. Valid range is 1 to 30 dB.

Constant

MINimum

MAXimum

DEFault

Description

1 dB

30 dB

15 dB

Attribute

Summary

Non- sequential command

Preset State: 15 dB

*RST State: 15 dB

SCPI Comp liance: instrument sp ecific

Description

A laser line is identified as a valid p eak if its amp litude is greater

than the p eak excursion p lus the amp litudes of the closest local min-

ima on either side of the p eak. This command works in conjunction

with the p eak threshold setting. Refer to “PTHReshold” on p age 4- 34 .

Changing the p eak excursion limit causes the instrument to rep rocess

the current set of data. Refer also to “Defining Laser- Line Peaks” on

page 2- 15.

The query resp onse is the current value. For examp le, if the current

value is set to 15 dB, the following value is returned:

4-33

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Programming Commands

CALCulate2 Subsystem

Non-sequential command

Always use an *OPC? query or a *WAI command to ensure that this command has

the time to complete before sending any more commands to the instrument. Refer

to “Always force the Agilent 86120C to wait for non-sequential commands” on

page 3-12 for more information.

POINts?

Queries the number of points in the data set.

Syntax

:CALCulate2:POINts?

Attribute

Summary

Preset State: unaffected

*RST State: unaffected

SCPI Comp liance: instrument sp ecific

Query Only

Description

This is the number of p oints that will be returned by the

CALC2:DATA? query.

Query Response

For examp le, if six laser lines are located:

PTHReshold

Sets the p eak threshold limit used by the instrument to determine

valid laser line peaks.

Syntax

:CALCulate2:PTHReshold{?| {<integer> | MINimum | MAXimum | DEFault}}

<integer> rep resents logarithmic units in dB. Valid range is 0 to 40.

Constant

Value

0 dB

MINimum

MAXimum

40 dB

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Programming Commands

CALCulate2 Subsystem

DEFault

10 dB

Attribute

Summary

Non- sequential command

Preset State: 10 dB

*RST State: 10 dB

SCPI Comp liance: instrument sp ecific

Description

A laser line is identified as a valid p eak if its amp litude is above the

maximum amp litude minus the p eak threshold value. The subtraction

is done in dB units. This setting works in conjunction with the peak

excursion setting to determine which responses are located. Refer to

“PEXCursion” on page 4- 33. Changing the p eak threshold limit causes

the instrument to rep rocess the current set of data. Refer also to

“Defining Laser- Line Peaks” on page 2- 15.

The query resp onse is the current value. For examp le, if the current

value is set to 15 dB, the following value is returned:

Non-sequential command

Always use an *OPC? query or a *WAI command to ensure that this command has

the time to complete before sending any more commands to the instrument. Refer

to “Always force the Agilent 86120C to wait for non-sequential commands” on

page 3-12 for more information.

PWAVerage[:STATe]

Places the instrument in the power- weighted average mode.

:CALCulate2:PWAVerage[:STATe]{?| {ON | OFF | 1 | 0}}

Syntax

Attribute

Summary

Preset State: off

*RST State: off

Description

When the state is on, the CALC2:DATA? POW query returns the total

power and the CALC2:DATA? WAV, FREQ, or WNUM query returns the

power- weighted average wavelength, frequency, or wave number val-

ues.

4-35

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Programming Commands

CALCulate2 Subsystem

Turning power- weighted average mode on while making delta, Fabry-

Perot, or signal- to- noise measurements results in a “–221 Settings con-

flict” error.

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Programming Commands

CALCulate2 Subsystem

WLIMit[:STATe]

Turns wavelength limiting on and off.

:CALCulate2:WLIMit[:STATe]{?| {ON | OFF | 1 | 0}}

Syntax

Attribute

Summary

Non- sequential command

Preset State: on

*RST State: on

SCPI Comp liance: instrument sp ecific

Description

When this function is on, the Agilent 86120C has an input range from

the WLIMit STARt to the WLIMit STOP. When this function is off, the

instrument displays peaks over the full wavelength range. The graphics

disp lay always shows the range between WLIMit:STARt and

WLIMit:STOP, regardless of the state of this command.

Whenever the Agilent 86120C receives this command, it rep rocesses

the data and p erforms a new p eak search.

Non-sequential command

Always use an *OPC? query or a *WAI command to ensure that this command has

the time to complete before sending any more commands to the instrument. Refer

to “Always force the Agilent 86120C to wait for non-sequential commands” on

page 3-12 for more information.

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Programming Commands

CALCulate2 Subsystem

WLIMit:STARt:FREQuency

Sets the start frequency for the wavelength limit range.

Syntax

:CALCulate2:WLIMit:STARt:FREQuency {?|{<real> | MINimum | MAXimum }}

<real> is a frequency value that is within the following limits:

Constant

Description

MINimum

MAXimum

181.6924 THz (1650 nm)

wavelength limit stop value

Attribute

Summary

Non- sequential command

Preset State: 181.6924 THz

*RST State: 181.6924 THz

SCPI Comp liance: instrument sp ecific

Description

This command sets the starting range for the wavelength limit in hertz.

The start frequency value must be less than or equal to the stop fre-

quency value or the start frequency will be clip p ed to the stop fre-

quency and a “Data out of range” error will be generated. The default

units for the <real> p arameter are hertz.

Non-sequential command

Always use an *OPC? query or a *WAI command to ensure that this command has

the time to complete before sending any more commands to the instrument. Refer

to “Always force the Agilent 86120C to wait for non-sequential commands” on

page 3-12 for more information.

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Programming Commands

CALCulate2 Subsystem

WLIMit:STARt[:WAVelength]

Syntax

CALCulate2:WLIMit:STARt[:WAVelength] {?|{<real> | MINimum | MAXimum}}

<real> is a wavenumber value that is within the following limits:

Constant

Description

MINimum

MAXimum

1270 nm

wavelength limit stop value

Attribute

Summary

Non- sequential command

Preset State: 1270 nm

*RST State: 1270 nm

SCPI Comp liance: instrument sp ecific

Description

This command sets the starting range for the wavelength limit. The start

wavelength value must be less than or equal to the stop wavelength

value or the start wavelength will be clipped to the stop wavelength and

a “Data out of range” error will be generated. Setting the start

wavelength is equivalent to setting the stop frequency/wavenumber

because of the inverse relationship of frequency to wavelength. The

default units for the <real> p arameter are meters.

Non-sequential command

Always use an *OPC? query or a *WAI command to ensure that this command has

the time to complete before sending any more commands to the instrument. Refer

to “Always force the Agilent 86120C to wait for non-sequential commands” on

page 3-12 for more information.

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Programming Commands

CALCulate2 Subsystem

WLIMit:STARt:WNUMber

Sets the starting wavenumber for the wavelength limit range.

Syntax

:CALCulate2:WLIMit:STARt:WNUMber {?|{<real> | MINimum | MAXimum}}

<real> is a wavenumber value that is within the following limits:

Constant

Description

MINimum

MAXimum

6060 cm^-1(1650 nm)

wavelength limit stop value

Attribute

Summary

Non- sequential command

Preset State: 6.060606E5 m^-1

*RST State: 6.060606E5 m^-1

SCPI Comp liance: instrument sp ecific

Description

This command sets the starting range for the wavelength limit. The

default units for the <real> p arameter value are m ^-1. The start wave-

number value must be less than or equal to the stop wavenumber

value or the start wavenumber will be clipped to the stop wavenumber

and a “Data out of range” error will be generated.

Non-sequential command

Always use an *OPC? query or a *WAI command to ensure that this command has

the time to complete before sending any more commands to the instrument. Refer

to “Always force the Agilent 86120C to wait for non-sequential commands” on

page 3-12 for more information.

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Programming Commands

CALCulate2 Subsystem

WLIMit:STOP:FREQuency

Sets the stopping frequency for the wavelength limit range.

Syntax

:CALCulate2:WLIMit:STOP:FREQuency {?|{<real> | MINimum | MAXimum }}

<real> is a frequency value that is within the following limits:

Constant

Description

MINimum

MAXimum

start wavelength limit

236.0571 THz (1270 nm)

Attribute

Summary

Non- sequential command

Preset State: 236.0571 THz

*RST State: 236.0571 THz

SCPI Comp liance: instrument sp ecific

Description

This command sets the stopping range for the wavelength limit. The

default units for the <real> p arameter are Hz. The stop frequency

value must be greater than or equal to the start frequency value or the

stop frequency will be clipped to the start frequency and a “Data out

of range” error will be generated.

Non-sequential command

Always use an *OPC? query or a *WAI command to ensure that this command has

the time to complete before sending any more commands to the instrument. Refer

to “Always force the Agilent 86120C to wait for non-sequential commands” on

page 3-12 for more information.

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Programming Commands

CALCulate2 Subsystem

WLIMit:STOP[:WAVelength]

Sets the stop p ing wavelength for the wavelength limit range.

Syntax

:CALCulate2:WLIMit:STOP[:WAVelength] {?|{<real> | MINimum | MAXimum }}

<real> is a wavelength value that is within the following limits:

Constant

Description

MINimum

MAXimum

start wavelength limit

1650.0 nm

Attribute

Summary

Non- sequential command

Preset State: 1650 nm

*RST State: 1650 nm

SCPI Comp liance: instrument sp ecific

Description

This command sets the stopping range for the wavelength limit. The

default units for the <real> parameter are meters. The stop wavelength

value must be greater than or equal to the start wavelength value or

the stop wavelength will be clipped to the start wavelength and a

“Data out of range” error will be generated. Setting the start wave-

length is equivalent to setting the start frequency/wavenumber because

of the inverse relationship of frequency to wavelength.

Non-sequential command

Always use an *OPC? query or a *WAI command to ensure that this command has

the time to complete before sending any more commands to the instrument. Refer

to “Always force the Agilent 86120C to wait for non-sequential commands” on

page 3-12 for more information.

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Programming Commands

CALCulate2 Subsystem

WLIMit:STOP:WNUMber

Sets the stop p ing wavenumber for the wavelength limit range.

Syntax

:CALCulate2:WLIMit:STOP:WNUMber {?|{<real> | MINimum | MAXimum }}

<real> is a wavenumber value that is within the following limits:

Constant

Description

MINimum

MAXimum

start wavelength limit

7874 cm^-1(1270 nm)

Attribute

Summary

Non- sequential command

Preset State: 7.87401E5 m^-1

*RST State: 7.87401E5 m^-1

SCPI Comp liance: instrument sp ecific

Description

This command sets the stopping range for the wavelength limit. The

default units for the <real> p arameter are inverse meters. The stop

wavenumber value must be less than or equal to the start wavenumber

value or the stop wavenumber will be clipped to the start wavenumber

and a “Data out of range” error will be generated.

Non-sequential command

Always use an *OPC? query or a *WAI command to ensure that this command has

the time to complete before sending any more commands to the instrument. Refer

to “Always force the Agilent 86120C to wait for non-sequential commands” on

page 3-12 for more information.

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Programming Commands

CALCulate3 Subsystem

Use the CALCulate3 commands to perform delta, drift, signal- to- noise,

and Fabry- Perot measurements. The commands in this subsystem have

the following command hierarchy:

:CALCulate3

:ASNR

:CLEar

:COUNt

[:STATe]

:DATA?

:DELTa

:POWer

[:STATe]

:PRESet

:REFerence

:FREQuency

:POWer?

[:WAVelength]

:WNUMber

:WAVelength

[:STATe]

:WPOWer

[:STATe]

:DRIFt

:DIFFerence

[:STATe]

:MAXimum

[:STATe]

:MINimum

[:STATe]

:PRESet

:REFerence

:RESet

[:STATe]

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Programming Commands

CALCulate3 Subsystem

:FPERot

[:STATE]

:FWHM

[:WAVelength]?

:FREQuency?

:WNUMber?

:MEAN

[:WAVelength]?

:FREQuency?

:WNUMber?

:MODE

[:WAVelength]?

:FREQuency?

:WNUMber?

:PEAK

[:WAVelength]?

:FREQuency?

:WNUMber?

:POWer?

:POWer

[:WAVelength]?

:FREQuency?

:WNUMber?

:SIGMa

[:WAVelength]?

:FREQuency?

:WNUMber?

:POINts?

:PRESet

:SNR

:AUTO

:REFerence

:FREQuency

[:WAVelength]

:WNUMber

[:STATe]

4-45

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Programming Commands

CALCulate3 Subsystem

ASNR:CLEar

Clears the number of measurements used in the average signal- to-

noise calculation.

Syntax

:CALCulate3:ASNR:CLEar

Attribute

Summary

Preset State: not affected

*RST State: not affected

SCPI Comp liance: instrument sp ecific

Description

This command clears the number of measurements used in the average

signal- to- noise calculation. The current measurement is used as the

new reference for the average signal- to- noise calculation.

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Programming Commands

CALCulate3 Subsystem

ASNR:COUNt

Sets the number of measurements to be used for the average signal- to-

noise calculation.

Syntax

:CALCulate3:ASNR:COUNt {?|{<integer> | MINimum | MAXimum }}

<integer> is a value that is within the following limits:

Constant

Description

MINimum

MAXimum

900

Attribute

Summary

Preset State: 100

*RST State: 100

SCPI Comp liance: instrument sp ecific

Description

This command sets the number of measurements to be used for the

average signal- to- noise calculation. If this count is changed while the

average signal calculation is on, and the new count is less than the

number of measurements already taken, the instrument will go into

single measurement mode.

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Programming Commands

CALCulate3 Subsystem

ASNR[:STATe]

Turns the average signal- to- noise ratio on or off.

:CALCulate3:ASNR[:STATe] {?|{ ON | OFF | 1 | 0 }}

Syntax

Attribute

Summary

Preset State: off

*RST State: off

SCPI Comp liance: instrument sp ecific

Description

This command turns the average signal- to- noise calculation on or off.

Only one of the CALCulate3 calculations (ASNR, DELTa, DRIFt, or

SNR) can be turned on at a time. Turning on the ASNR calculation

while another calculation is on will generate a “Settings conflict” error.

When the calculation is first turned on, the lines measured in the cur-

rent measurement will be used as the reference values for the signal-

to-noise ratio. Subsequent measurements will average the noise values.

The signal values are not updated until the number of measurements

used to average the noise is greater than or equal to the COUNt value.

Note

Only one STATe command can be turned on at any one time. Attempting to turn

more than one state on at a time results in a “–221 Settings Conflict” error. Refer

to “Measure delta, drift, and signal-to-noise” on page 3-14 for additional informa-

tion on selecting measurements.

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Programming Commands

CALCulate3 Subsystem

DATA?

Queries the data resulting from delta, drift, and signal- to- noise mea-

surements.

Syntax

:CALCulate3:DATA? {POWer | FREQuency | WAVelength | WNUMber}

Argument

POWer

Description

Queries the array of laser-line powers after the calculation is

completed.

FREQuency

WAVelength

WNUMber

Queries the array of laser-line frequencies after the calculation is

completed.

Queries the array of laser-line wavelengths after the calculation is

completed.

Queries the array of laser-line wave numbers after the calculation

is completed.

Attribute

Summary

Preset State: not affected

SCPI Compliance: standard

Query Only

Description

The data returned by the query dep ends up on which calculation state

is on. If no calculation state is on, an error is generated. The returned

data is comma delimited. The following string is a typ ical examp le of

six values returned when POWer is sp ecified from a delta p ower mea-

surement:

-7.42833100E+000,-1.00087200E+000,-2.52121400E+000,

-3.41918900E+000,-3.80437200E+000,-6.36282900E+000

Notice that only measurement values are returned to the comp uter.

There is no first value that indicates the number of values contained

in the string as there is, for examp le, with the FETCh, READ, and

MEASure commands. Use the CALC3:POIN? query to determine the

number of points the CALC3:DATA? query returns.

In the SNR or ASNR calculation, only the POWer argument is valid.

The other arguments will generate a “Settings conflict” error. Use the

CALC2:DATA? query to retrieve the signal wavelengths and powers.

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Programming Commands

CALCulate3 Subsystem

DELTa:POWer[:STATe]

Turns the delta-power measurement mode on and off.

:CALCulate3:DELTa:POWer[:STATe]{?| {ON | OFF | 1 | 0}}

Syntax

Attribute

Summary

Preset State: off

*RST State: off

SCPI Comp liance: instrument sp ecific

Description

When this state is on, the p ower of the reference laser line is sub-

tracted from the p ower values of all laser lines excep t the reference.

The p ower data returned by the CALC3:DATA? query is the array of

laser line power levels normalized to the power level of the reference

laser line. The power of the reference laser line is returned as an

absolute p ower (unnormalized). The frequency data returned is the

array of absolute frequency values.

Note

Only one STATe command can be turned on at any one time. Attempting to turn

more than one state on at a time results in a “–221 Settings Conflict” error. Refer

to “Measure delta, drift, and signal-to-noise” on page 3-14 for additional informa-

tion on selecting measurements.

DELTa:PRESet

Turns off all delta measurement states.

:CALCulate3:DELTa:PRESet

Syntax

Attribute

Summary

Preset State: not affected

*RST State: not affected

SCPI Comp liance: instrument sp ecific

Command Only

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Programming Commands

CALCulate3 Subsystem

DELTa:REFerence:FREQuency

Selects the reference laser line for DELTa calculations.

Syntax

:CALCulate3:DELTa:REFerence:FREQuency{?| {<real> | MINimum | MAXimum}}

<real> is a frequency value that is within the following limits:

Constant

Description

181.6924 THz

236.0571 THz

MINimum

MAXimum

Attribute

Summary

Preset State: 236.0571 THz (1270 nm)

*RST State: 236.0571 THz (1270 nm)

SCPI Comp liance: instrument sp ecific

Description

The reference will be the laser line at the frequency closest to the fre-

quency entered. Subsequent measurements will use the frequency clos-

est to the reference frequency used for the previous measurement.

The query returns the reference laser line’s frequency. The default

units for the <real> p arameter are Hz.

DELTa:REFerence:POWer?

Queries the reference laser line’s power level.

:CALCulate3:DELTa:REFerence:POWer?

Syntax

Attribute

Summary

Preset State: not affected

*RST State: not affected

SCPI Comp liance: instrument sp ecific

Query Only

4-51

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Programming Commands

CALCulate3 Subsystem

DELTa:REFerence[:WAVelength]

Selects the reference laser line for DELTa calculations.

Syntax

:CALCulate3:DELTa:REFerence[:WAVelength]{?| {<real> | MINimum | MAXimum}}

<real> is a wavelength value that is within the following limits:

Constant

Description

1270 nm

MINimum

MAXimum

1650 nm

Attribute

Summary

Preset State: 1270 nm (236.0571 THz)

*RST State: 1270 nm (236.0571 THz) laser line

SCPI Comp liance: instrument sp ecific

Description

The reference will be the laser line at the wavelength closest to the

wavelength entered. Subsequent measurements will use the wavelength

closest to the reference wavelength used for the previous measurement.

The query returns the current wavelength of the reference laser line.

The default units for the <real> parameter are meters.

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Programming Commands

CALCulate3 Subsystem

DELTa:REFerence:WNUMber

Selects the reference laser line for delta calculations.

Syntax

:CALCulate3:DELTa:REFerence:WNUMber{?| {<real> | MINimum | MAXimum}}

<real> is a wave number value that is within the following limits:

Constant

Description

MINimum

MAXimum

6,060 cm^-1(1650 nm)

7,824 cm^-1(1270 nm)

Attribute

Summary

Preset State: 7,824 cm^-1(1270 nm)

*RST State: 7,824 cm^-1(1270 nm)

SCPI Comp liance: instrument sp ecific

Description

The reference will be the laser line at the wave number closest to the

wave number entered. Subsequent measurements will use the wave

number closest to the reference wave number used for the p revious

measurement.

The query returns the current wave number of the reference laser line.

–1

The default units for the <real> p arameter are m

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Programming Commands

CALCulate3 Subsystem

DELTa:WAVelength[:STATe]

Turns the delta wavelength measurement mode on and off.

:CALCulate3:DELTa:WAVelength[:STATe]{?| {ON | OFF | 1 | 0}}

Syntax

Attribute

Summary

Preset State: off

*RST State: off

SCPI Comp liance: instrument sp ecific

Description

When on, the wavelength of the reference laser line is subtracted from

the wavelength values of all laser lines excep t the reference.

For the CALC3:DATA? query, the p ower data returned is the array of

absolute p owers measured for each laser line. The frequency data is

the array of frequency values normalized to the frequency of the refer-

ence laser line. The frequency of the reference laser line is returned as

an absolute frequency (unnormalized).

Note

Only one STATe command can be turned on at any one time. Attempting to turn

more than one state on at a time results in a “–221 Settings Conflict” error. Refer

to “Measure delta, drift, and signal-to-noise” on page 3-14 for additional informa-

tion on selecting measurements.

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Programming Commands

CALCulate3 Subsystem

DELTa:WPOWer[:STATe]

Turns the delta wavelength and power measurement mode on and off.

Syntax

:CALCulate3:DELTa:WPOWer[:STATe]{?| {ON | OFF | 1 | 0}}

Attribute

Summary

Preset State: off

*RST State: off

SCPI Comp liance: instrument sp ecific

Description

When on, the wavelength of the reference laser line is subtracted from

the wavelength values of all laser lines excep t the reference. The

power value of the reference is subtracted from the power values of all

laser lines except the reference.

For the CALC3:DATA? query, the p ower data returned is the array of

powers normalized to the power of the reference laser line. The power

of the reference laser line is returned as an absolute p ower (unnor-

malized).

The frequency data is the array of frequency values normalized to the

frequency of the reference laser line. The frequency of the reference

laser line is returned as an absolute frequency (unnormalized).

Note

Only one STATe command can be turned on at any one time. Attempting to turn

more than one state on at a time results in a “–221 Settings Conflict” error. Refer

to “Measure delta, drift, and signal-to-noise” on page 3-14 for additional informa-

tion on selecting measurements.

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Programming Commands

CALCulate3 Subsystem

DRIFt:DIFFerence[:STATe]

Sets the drift calculation to subtract the minimum values measured

from the maximum values measured.

Syntax

:CALCulate3:DRIFt:DIFFerence[:STATe]{?| {ON | OFF | 1 | 0}}

Attribute

Summary

Preset State: off

*RST State: off

SCPI Comp liance: instrument sp ecific

Description

Use the CALC3:DRIF:PRES command to turn off all the drift states

before turning on this state. The CALC3:DATA? query returns the max-

imum p ower and frequency minus the minimum p ower and frequency.

Note

Only one STATe command can be turned on at any one time. Attempting to turn

more than one state on at a time results in a “–221 Settings Conflict” error. Refer

to “Measure delta, drift, and signal-to-noise” on page 3-14 for additional informa-

tion on selecting measurements.

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Programming Commands

CALCulate3 Subsystem

DRIFt:MAXimum[:STATe]

Sets the drift calculation to return the maximum power and frequency

values measured.

Syntax

:CALCulate3:DRIFt:MAXimum[:STATe]{?| {ON | OFF | 1 | 0}}

Attribute

Summary

Preset State: off

*RST State: off

SCPI Comp liance: instrument sp ecific

Description

Use the CALC3:DRIF:PRES command to turn off all the drift states

before turning on this state. The CALC3:DATA? query returns the max-

imum p ower and frequency.

Note

Only one STATe command can be turned on at any one time. Attempting to turn

more than one state on at a time results in a “–221 Settings Conflict” error. Refer

to “Measure delta, drift, and signal-to-noise” on page 3-14 for additional informa-

tion on selecting measurements.

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Programming Commands

CALCulate3 Subsystem

DRIFt:MINimum[:STATe]

Sets the drift calculation to return the minimum p ower and frequency

values measured.

Syntax

:CALCulate3:DRIFt:MINimum[:STATe]{?| {ON | OFF | 1 | 0}}

Attribute

Summary

Preset State: off

*RST State: off

SCPI Comp liance: instrument sp ecific

Description

Use the CALC3:DRIF:PRES command to turn off all the drift states

before turning on this state. The CALC3:DATA? query returns the min-

imum p ower or frequency.

Note

Only one STATe command can be turned on at any one time. Attempting to turn

more than one state on at a time results in a “–221 Settings Conflict” error. Refer

to “Measure delta, drift, and signal-to-noise” on page 3-14 for additional informa-

tion on selecting measurements.

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Programming Commands

CALCulate3 Subsystem

DRIFt:PRESet

Turns off all the drift states for DIFFerence, MAXimum, MINimum, and

REFerence.

Syntax

:CALCulate3:DRIFt:PRESet

Attribute

Summary

Preset State: unaffected by

*RST State: unaffected by

SCPI Comp liance: instrument sp ecific

Command Only

Description

This command allows the CALC3:DATA? query to return the difference

between the current measurement and the reference.

DRIFt:REFerence:RESet

Places the current list of laser lines into the reference list.

:CALCulate3:DRIFt:REFerence:RESet

Syntax

Attribute

Summary

Preset State: unaffected by

*RST State: unaffected by

SCPI Comp liance: instrument sp ecific

Command Only

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Programming Commands

CALCulate3 Subsystem

DRIFt:REFerence[:STATe]

Turns on and off the drift reference state.

:CALCulate3:DRIFt:REFerence[:STATe]{?| {ON | OFF | 1 | 0}}

Syntax

Attribute

Summary

Preset State: off

*RST State: off

SCPI Comp liance: instrument sp ecific

Description

When this command is set to on, the CALC3:DATA? command returns

the reference laser lines. Use the CALC3:DRIF:PRES command to turn

off all the drift states before turning on the drift reference state.

Note

Only one STATe command can be turned on at any one time. Attempting to turn

more than one state on at a time results in a “–221 Settings Conflict” error. Refer

to “Measure delta, drift, and signal-to-noise” on page 3-14 for additional informa-

tion on selecting measurements.

4-60

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Programming Commands

CALCulate3 Subsystem

DRIFt[:STATe]

Turns on and off the drift measurement calculation.

:CALCulate3:DRIFt[:STATe]{?| {ON | OFF | 1 | 0}}

Syntax

Attribute

Summary

Preset State: off

*RST State: off

SCPI Comp liance: instrument sp ecific

Description

When the drift mode is first turned on, the current list of laser lines is

placed into the reference. All subsequent measurements take the new

data, subtract the reference data, and disp lay the differences in wave-

lengths and powers.

The CALC3:DATA? query returns the power and frequency of the cur-

rent measurement minus the p ower and frequency of the reference.

Note

Only one STATe command can be turned on at any one time. Attempting to turn

more than one state on at a time results in a “–221 Settings Conflict” error. Refer

to “Measure delta, drift, and signal-to-noise” on page 3-14 for additional informa-

tion on selecting measurements.

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Programming Commands

CALCulate3 Subsystem

FPERot[:STATE]

Turns on and off the Fabry- Perot measurement mode.

:CALCulate3:FPERot[:STATE] {? | {ON | OFF | 1 | 0}}

Syntax

Attribute

Summary

Preset State: off

*RST State: off

SCPI Comp liance: instrument sp ecific

Description

When the state is ON, the Agilent 86120C measures characteristics of

the Fabry- Perot laser modes. The modes are defined by the peak

excursion and peak threshold commands.

FPERot:FWHM?

Queries the full width half- maximum data of the selected modes.

:CALCulate3:FPERot:FWHM{[:WAVelength] | :FREQuency | :WNUMber}?

Syntax

Argument

Description

WAVelength

Returns the full width half-maximum wavelength of the selected

modes.

FREQuency

WNUMber

Returns the full width half-maximum frequency of the selected

modes.

Returns the full width half-maximum wavenumber of the selected

modes.

Example Query

Response

WAVelength

FREQuency

WNUMber

+5.47128800E–009

+6.93436400E+011

+2.31306200E+001

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Programming Commands

CALCulate3 Subsystem

Attribute

Summary

Preset State: not affected

*RST State: not affected

SCPI Comp liance: instrument sp ecific

Query only

FPERot:MEAN?

Queries the mean data of the selected modes.

:CALCulate3:FPERot:MEAN{[:WAVelength] | :FREQuency | :WNUMber}?

Syntax

Argument

Description

WAVelength

FREQuency

WNUMber

Returns the mean wavelength of the selected modes.

Returns the mean frequency of the selected modes.

Returns the mean wavenumber of the selected modes.

Example Query

Response

WAVelength

FREQuency

WNUMber

+1.53878000E-006

+1.94824800E+014

+6.49865400E+003

Attribute

Summary

Preset State: not affected

*RST State: not affected

Query only

SCPI Comp liance: instrument sp ecific

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Programming Commands

CALCulate3 Subsystem

FPERot:MODE:SPACing?

Queries the mode spacing data of the selected modes.

:CALCulate3:FPERot:MODE:SPACing{[:WAVelength] | :FREQuency | :WNUMber}?

Syntax

Argument

Description

WAVelength

FREQuency

WNUMber

Returns the mode spacing wavelength of the selected modes.

Returns the mode spacing frequency of the selected modes.

Returns the mode spacing wavenumber of the selected modes.

Example Query

Response

WAVelength

FREQuency

WNUMber

+3.18277200E–010

+4.02787400E+011

+1.34356200E+001

Attribute

Summary

Preset State: not affected

*RST State: not affected

SCPI Comp liance: instrument sp ecific

Query only

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Programming Commands

CALCulate3 Subsystem

FPERot:PEAK?

Queries the peak data of the selected modes.

Syntax

:CALCulate3:FPERot:PEAK{[:WAVelength] | :FREQuency | :WNUMber | :POWer{[:DBM]|:WATTs}}?

Argument

WAVelength

FREQuency

WNUMber

POWer

Description

Returns the peak wavelength of the selected modes.

Returns the peak frequency of the selected modes.

Returns the peak wavenumber of the selected modes.

Returns the peak amplitude of the selected modes in dBm or

watts.

Example Query

Response

WAVelength

FREQuency

WNUMber

POWer

+1.54073400E–006

+1.94577600E+014

+6.49041000E+003

–9.09446600E+000 (dBm)

+1.23183800E–004 (watts)

Attribute

Summary

Preset State: not affected

*RST State: not affected

SCPI Comp liance: instrument sp ecific

Query only

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Programming Commands

CALCulate3 Subsystem

FPERot:POWer?

Queries the total power data of the selected modes.

:CALCulate3:FPERot:POWer{[:DBM]|:WATTs}}?

Syntax

Argument

DBM

Description

Returns the total power in dBm.

Returns the total power in watts.

WATTs

Example Query

Response

dBm (DBM)

–4.46895600E+000

+3.57358800E–004

watts (WATTs)

Attribute

Summary

Preset State: not affected

*RST State: not affected

SCPI Comp liance: instrument sp ecific

Query only

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Programming Commands

CALCulate3 Subsystem

FPERot:SIGMa?

Queries the sigma data of the selected modes.

:CALCulate3:FPERot:SIGMa{[:WAVelength] | :FREQuency | :WNUMber}?

Syntax

Argument

Description

WAVelength

FREQuency

WNUMber

Returns the sigma wavelength of the selected modes.

Returns the sigma frequency of the selected modes.

Returns the sigma wavenumber of the selected modes.

Example Query

Response

WAVelength

FREQuency

WNUMber

+2.32784700E–009

+2.94452900E+011

+9.82124900E+000

Attribute

Summary

Preset State: not affected

*RST State: not affected

SCPI Comp liance: instrument sp ecific

Query only

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Programming Commands

CALCulate3 Subsystem

POINts?

Queries the number of points in the data set.

Syntax

:CALCulate3:POINts?

Attribute

Summary

Preset State: unaffected by

RST State: unaffected by

SCPI Comp liance: instrument sp ecific

Query Only

Description

The value returned is the number of points returned by the

CALC3:DATA? query.

PRESet

Turns off any CALCulate3 calculation that is on.

Syntax

:CALCulate3:PRESet

Attribute

Summary

Preset State: unaffected by

RST State: unaffected by

SCPI Comp liance: instrument sp ecific

Command Only

Description

This command turns off any CALCulate3 calculation (delta, drift,

Fabry- Perot, or signal- to- noise) that is on.

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Programming Commands

CALCulate3 Subsystem

SNR:AUTO

Selects the reference frequency value for measuring noise in the sig-

nal- to- noise calculation.

Syntax

:CALCulate3:SNR:AUTO{?| {ON | OFF | 1 | 0}}

Constant

Description

Selects internally generated reference frequency.

Selects user-entered reference frequency.

OFF

Attribute

Summary

Preset State: on

*RST State: on

SCPI Comp liance: instrument sp ecific

Description

The command argument allows you to select either an internally gen-

erated or a user- entered frequency reference for measuring the noise.

To enter a value to use as the reference, use the SNR:REFerence:FRE-

Quency, SNR:REFerence:WAVelength, and SNR:REFerence:WNUMber

commands.

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Programming Commands

CALCulate3 Subsystem

SNR:REFerence:FREQuency

Enters a frequency that can be used for the noise measurement refer-

ence in signal-to- noise calculations.

Syntax

:CALCulate3:SNR:REFerence:FREQuency{?| {<real> | MINimum | MAXimum}}

<real> is a frequency value that is within the following limits:

Constant

Description

181.6924 THz

236.0571 THz

MINimum

MAXimum

Attribute

Summary

Preset State: unaffected by

*RST State: 193.4145 THz (1550.0 nm in a vacuum)

SCPI Comp liance: instrument sp ecific

Description

After entering this value, use the SNR:AUTO command to configure the

instrument to use this value in subsequent signal- to- noise calculations.

The default units for the <real> p arameter are Hz.

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Programming Commands

CALCulate3 Subsystem

SNR:REFerence[:WAVelength]

Sets the wavelength used for the noise measurement reference in the

signal- to- noise calculation.

Syntax

:CALCulate3:SNR:REFerence[:WAVelength]{?| {<real> | MINimum | MAXimum}}

<real> is a wavelength value that is within the following limits:

Constant

Description

1270 nm

MINimum

MAXimum

1650 nm

Attribute

Summary

Preset State: unaffected by

*RST State: 1550.0 nm in a vacuum

SCPI Comp liance: instrument sp ecific

Description

After entering this value, use the SNR:AUTO command to configure the

instrument to use this value in subsequent signal- to- noise calculations.

The number entered is converted internally to the corresponding fre-

quency.

The default units for the <real> parameter are meters.

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Programming Commands

CALCulate3 Subsystem

SNR:REFerence:WNUMber

Sets the wave number used for the noise measurement reference in the

signal- to- noise calculation.

Syntax

:CALCulate3:SNR:REFerence:WNUMber{?| {<real> | MINimum | MAXimum}}

<real> is a wave number value that is within the following limits:

Constant

Description

MINimum

MAXimum

6060 cm^-1(1650 nm)

7874 cm^-1(1270 nm)

Attribute

Summary

Preset State: unaffected by

*RST State: 6451.614 cm^-1(1550 nm)

SCPI Comp liance: instrument sp ecific

Description

After entering this value, use the SNR:AUTO command to configure the

instrument to use this value in subsequent signal- to- noise calculations.

The wave number entered is converted internally to the corresponding

frequency.

–1

The default units for the <real> p arameter are m

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Programming Commands

CALCulate3 Subsystem

SNR[:STATe]

Turns the signal-to- noise calculation on and off.

:CALCulate3:SNR[:STATe]{?| {ON | OFF | 1 | 0}}

Syntax

Attribute

Summary

Preset State: off

*RST State: off

SCPI Comp liance: instrument sp ecific

Note

Only one STATe command can be turned on at any one time. Attempting to turn

more than one state on at a time results in a “–221 Settings Conflict” error. Refer

to “Measure delta, drift, and signal-to-noise” on page 3-14 for additional informa-

tion on selecting measurements.

4-73

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Programming Commands

CONFigure Measurement Instruction

For information on the CONFigure measurement instruction, refer to

“Measurement Instructions” on page 4- 15.

4-74

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Programming Commands

DISPlay Subsystem

The commands in this subsystem have the following command hierar-

chy:

:DISPlay

:MARKer:

:MAXimum

:LEFT

:NEXT

:PREVious

:RIGHt

[:WINDow]

:GRAPhics

:STATe

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Programming Commands

DISPlay Subsystem

MARKer:MAXimum

Sets the marker to the laser line that has the maximum p ower.

:DISPlay:MARKer:MAXimum

Syntax

Attribute

Summary

Preset State: marker set to maximum- p ower laser line

*RST State: marker set to maximum- p ower laser line

SCPI Comp liance: instrument sp ecific

Command Only

MARKer:MAXimum:LEFT

Moves the marker left to the next laser line.

:DISPlay:MARKer:MAXimum:LEFT

Syntax

Attribute

Summary

Preset State: marker set to maximum- p ower laser line

*RST State: marker set to maximum- p ower laser line

SCPI Comp liance: instrument sp ecific

Command Only

Description

Moves the marker from the current marker p osition to the next laser

line having the following characteristic:

• shorter wavelength

• lower frequency

• lower wave number

If the display is in the List by Ampl mode, it will be changed to List by

WL before the marker is moved.

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Programming Commands

DISPlay Subsystem

MARKer:MAXimum:NEXT

Moves the marker to the laser line with the next lower power level.

Syntax

:DISPlay:MARKer:MAXimum:NEXT

Attribute

Summary

Preset State: marker set to maximum- p ower laser line

*RST State: marker set to maximum- p ower laser line

SCPI Comp liance: instrument sp ecific

Command Only

Description

If the display is in the List by WL mode, it will be changed to List by

Ampl before the marker is moved.

MARKer:MAXimum:PREVious

Moves the marker to the laser line that has the next higher power

level.

Syntax

:DISPlay:MARKer:MAXimum:PREVious

Attribute

Summary

Preset State: marker set to maximum- p ower laser line

*RST State: marker set to maximum- p ower laser line

SCPI Comp liance: instrument sp ecific

Command Only

Description

If the display is in the List by WL mode, it will be changed to List by

Ampl before the marker is moved.

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Programming Commands

DISPlay Subsystem

MARKer:MAXimum:RIGHt

Moves the marker right to the next laser line.

:DISPlay:MARKer:MAXimum:RIGHt

Syntax

Attribute

Summary

Preset State: marker set to maximum- p ower laser line

*RST State: marker set to maximum- p ower laser line

SCPI Comp liance: instrument sp ecific

Command Only

Description

Moves the marker from the current marker p osition to the next laser

line having the following characteristic:

• longer wavelength

• higher frequency

• higher wave number

If the display is in the List by Ampl mode, it will be changed to List by

WL before the marker is moved.

[WINDow]:GRAPhics:STATe

Turns on and off the disp lay of the p ower bars.

:DISPlay[:WINDow]:GRAPhics:STATe{?| {ON | OFF | 1 | 0}}

Syntax

Attribute

Summary

Preset State: on

*RST State: on

SCPI Compliance: standard

Description

Sp ecifying on disp lays the p ower bars in all modes excep t the drift

and signal- to- noise modes. Sp ecifying off p revents the disp lay of

power bars for all instrument modes.

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Programming Commands

FETCh Measurement Instruction

For information on the FETCh measurement instruction, refer to “Mea-

surement Instructions” on page 4- 15.

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Programming Commands

HCOPy Subsystem

Use the command in this subsystem to p rint the disp layed measure-

ment results to a p rinter. This subsystem has the following command

hierarchy:

:HCOPy

[:IMMediate]

Prints measurement results on a p rinter.

:HCOPy:IMMediate

Syntax

Attribute

Summary

Preset State: none

*RST State: none

SCPI Compliance: standard

Command Only

Description

Connect the printer to the Agilent 86120C’s rear- panel PARALLEL

PRINTER PORT connector. The output to the printer is ASCII text.

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Programming Commands

MEASure Measurement Instruction

For information on the MEASure measurement instruction, refer to

“Measurement Instructions” on page 4- 15.

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Programming Commands

READ Measurement Instruction

For information on the READ measurement instruction, refer to “Mea-

surement Instructions” on page 4- 15.

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Programming Commands

SENSe Subsystem

Use the SENSe commands to correct measurement results for elevation

above sea level and to select between measurements in air or vacuum.

You can also enter an amp litude offset. The commands in this sub-

system have the following command hierarchy:

[:SENSe]

:CORRection

:DEVice

:ELEVations

:MEDium

:OFFSet

[:MAGNitude]

:DATA?

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Programming Commands

SENSe Subsystem

CORRection:DEVice

Selects the wavelength measurement algorithm.

:SENSe:CORRection:[DEVice]{?| {NARRow | BROad}}

Syntax

Constant

NARRow

Description

Selects wavelength measurements for narrowband devices such

as DFB lasers and modes of FP lasers.

BROad

Selects wavelength measurements for broadband devices such

as optical filters and LEDs.

Attribute

Summary

Non- sequential command

Preset State: NARRow

*RST sets this value to NARRow

SCPI Comp liance: instrument sp ecific

Description

The narrow bandwidth algorithm, used for measuring lasers, deter-

mines the wavelength based up on the p eak.

The broad bandwidth algorithm, used for LEDs, filters, and chirp ed

lasers, determines the wavelength based up on the center- of- mass of

the power spectrum. The peak excursion function is used to determine

the value of the integration limits. Care must be taken to ensure that

the integration limits are above any noise. This is especially true when

measuring devices with sloping noise floors, like an EDFA amplifier.

For more information on peak excursion, refer to “PEXCursion” on

page 4- 33.

Instrument specifications apply when the device is set to NARRow.

Specifications do not apply in BROad mode.

Query Response

The query form returns the p reviously selected device.

NARRow

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Programming Commands

SENSe Subsystem

CORRection:ELEVation

Sets the elevation value used by the instrument to comp ensate for air

dispersion.

Syntax

:SENSe:CORRection:ELEVation{?| {<integer> | MINimum | MAXimum}}

<integer> is the altitude in meters.

Constant

Description

0 m

MINimum

MAXimum

5000 m

Attribute

Summary

Non- sequential command

Preset State: unaffected by

*RST sets this value to the minimum.

SCPI Comp liance: instrument sp ecific

0Description

Changing the elevation value causes the current data to be rep ro-

cessed.

Query Response

The query form returns the current elevation setting as shown in the

following example:

+1500

Non-sequential command

Always use an *OPC? query or a *WAI command to ensure that this command has

the time to complete before sending any more commands to the instrument. Refer

to “Always force the Agilent 86120C to wait for non-sequential commands” on

page 3-12 for more information.

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Programming Commands

SENSe Subsystem

CORRection:MEDium

Sets the Agilent 86120C to return wavelength readings in a vacuum or

standard air.

Syntax

:SENSe:CORRection:MEDium{?| {AIR | VACuum}}

Argument

AIR

Description

Selects wavelength values in standard air.

Selects wavelength values in a vacuum.

VACuum

Attribute

Summary

Preset State: VAC

*RST State: VAC

SCPI Comp liance: instrument sp ecific

Description

Standard air is defined to have the following characteristics:

Barometric pressure: 760 torr

Temperature:

Relative humidity: 0%

15°C

4-86

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Programming Commands

SENSe Subsystem

CORRection:OFFSet[:MAGNitude]

Enters an offset for amp litude values.

Syntax

:SENSe:CORRection:OFFSet:MAGNitude{?| {<real> | MINimum | MAXimum}}

<real> is the logarithmic units in dB.

Constant

Description

−40.0 dB

40.0 dB

MINimum

MAXimum

Attribute

Summary

Preset State: 0.0

*RST State: 0.0

SCPI Compliance: standard

Query Response

The query form returns the current offset setting as shown in the fol-

lowing example:

+5.00000000E+000

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Programming Commands

SENSe Subsystem

DATA?

Queries the time domain samp les of the inp ut laser line.

Syntax

:SENSe:DATA?

Attribute

Summary

Preset State: none

SCPI Comp liance: instrument sp ecific

Query Only

Description

Be p rep ared to p rocess a large amount of data when this query is

sent. The amount of data returned depends on the measurement

update state of the instrument which is set using the resolution argu-

ment of an instrument function. Refer to “Measurement Instructions”

on page 4- 15.

When NORMAL measurement up date is sp ecified, over 2,200 kilobytes

of data (2¹⁷values) can be returned to the comp uter. When

surement up date is sp ecified, over 1,100 kilobytes of data (2

can be returned.

FAST mea-

values)

The floating point values are scaled from 1.000 to 1.999756 (1 + 4095/

4096). Amplitude values are not calibrated.

The input laser line(s) generate an interference pattern on the photo-

detector as a function of the Michelson interferometer optical path

delay. The time domain data is samp led at uniform op tical p ath delay

increments of the reference laser wavelength, or 0.632991 microns.

When NORMAL measurement update is selected, the first data value is

samp led at –41.48 mm op tical p ath delay, and the last value is sam-

pled at +41.48 mm optical path delay. When FAST measurement update

is selected, the first data value is samp led at +20.74 mm op tical p ath

delay, and the last value is samp led at –20.74 mm op tical p ath delay.

The data value that corresp onds to zero op tical p ath delay is ap p roxi-

mately, but not exactly, located in the center of the time domain data.

If your program is aborted or interrupted after sending this query, the

Agilent 86120C continues to p rocess the data but does not p lace it in

the outp ut buffer. Because of the amount of data p rocessed, the

instrument will not respond to any new commands in its inp ut buffer

for 30 or 40 seconds.

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Programming Commands

SENSe Subsystem

Query Response

The following string shows an example of the first few measurements

returned by this query.

+1.51367200E+000,+1.51855500E+000,+1.49902300E+000,+1.47949200E+000,+1.50488300E+00

0,+1.53320300E+000,+1.50097700E+000,+1.47265600E+000,+1.50293000E+000,+1.50781300E+0

00,+1.51171900E+000,+1.48242200E+000,+1.50097700E+000,+1.51855500E+000,+1.50683600E+

000,+1.48632800E+000,+1.50488300E+000

Notice that only values are returned to the computer. There is no first

value that indicates the number of values contained in the string as

there is, for example, with the FETCh, READ, and MEASure com-

mands.

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Programming Commands

STATus Subsystem

Use the commands in this subsystem to control the Agilent 86120C’s

status- reporting structures. These structures provide registers that you

can use to determine if certain events have occurred.

The commands in this subsystem have the following command hierar-

chy:

:STATus

:OPERation

:CONDition?

:ENABle

[:EVENt]?

:PTRansition

:NTRansition

:PRESet

:QUEStionable

:CONDition?

:ENABle

[:EVENt]?

:PTRansition

:NTRansition

4-90

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Programming Commands

STATus Subsystem

{OPERation | QUEStionable}:CONDition?

Queries the value of the questionable or operation condition register.

Syntax

:STATus:{OPERation | QUEStionable}:CONDition?

0 to 32767

Query Response

Attribute

Summary

Preset State: none

*RST State: none

SCPI Compliance: standard

Query Only

Description

Example

Use this command to read the value of the OPERation Status or

QUEStionable Status registers. Refer to “Monitoring the Instrument” on

page 3- 16.

OUTPUT 720;”:STATUS:OPERATION:CONDITION?”

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Programming Commands

STATus Subsystem

{OPERation | QUEStionable}:ENABle

Sets the enable mask for the questionable or op eration event register.

Syntax

:STATus:{OPERation | QUEStionable}:ENABle{?| <value>}

<integer> an integer from 0 to 65535.

Attribute

Summary

Preset State: none

*RST State: none

SCPI Compliance: standard

Description

The enable mask selects which conditions in the event register cause

the summary bit in the status byte to be set. If a bit in the enable

mask is set true and the corresponding event occurs, the summary bit

(bit 3 for the questionable status or bit 7 for the op eration status) in

the status byte will be set.

Example

OUTPUT 720;”:STATUS:QUESTIONABLE:ENABLE 1024”

Query Response

When queried, the largest value that can be returned is 65535. This is

because the most- significant register bit cannot be set true.

4-92

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Programming Commands

STATus Subsystem

{OPERation | QUEStionable}[:EVENt]

Queries the contents of the questionable or operation event registers.

Syntax

:STATus:{OPERation | QUEStionable}:EVENt?

0 to 32767

Query Response

Attribute

Summary

Preset State: none

*RST State: none

SCPI Compliance: standard

Query Only

Description

Example

The resp onse will be a number from 0 to 32767 indicating which bits

are set. Reading the register clears the register.

OUTPUT 720;”:STATUS:OPERATION:EVENT?”

4-93

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Programming Commands

STATus Subsystem

{OPERation | QUEStionable}:NTRansition

Selects bits in the event register which can be set by negative transi-

tions of the corresp onding bits in the condition register.

Syntax

:STATus:OPERation:NTRansition{?| <integer>}

<integer> an integer from 0 to 65535.

Attribute

Summary

Preset State: none

*RST State: none

SCPI Compliance: standard

Description

Changes in the state of a condition register bit causes the associated

OPERation Status or QUEStionable Status register bit to be set. This

command allows you to select a negative bit transition to trigger an

event to be recognized. A negative transition is defined to occur when-

ever the selected bit changes states from a 1 to a 0. You can enter any

value from 0 to 65535.

When queried, the largest value that can be returned is 32767. This is

because the most- significant register bit cannot be set true.

Example

OUTPUT 720;”:STATUS:OPER:NTRansition 16”

4-94

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Programming Commands

STATus Subsystem

{OPERation | QUEStionable}:PTRansition

Selects bits in the event register which can be set by p ositive transi-

tions of the corresp onding bits in the condition register.

Syntax

:STATus:OPERation:PTRansition{?| <integer>}

<integer> an integer from 0 to 65535.

Attribute

Summary

Preset State: none

*RST State: none

SCPI Compliance: standard

Description

Changes in the state of a condition register bit causes the associated

OPERation Status or QUEStionable Status event register bit to be set.

This command allows you to select a positive bit transition to trigger

an event to be recognized. A p ositive transition is defined to occur

whenever the selected bit changes states from a 0 to a 1. You can

enter any value from 0 to 65535.

When queried, the largest value that can be returned is 32767. This is

because the most- significant register bit cannot be set true.

Example

OUTPUT 720;”:STATUS:OPER:PTRansition 16”

4-95

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Programming Commands

STATus Subsystem

PRESet

Presets the enable registers and the PTRansition and NTRansition fil-

ters.

Syntax

:STATus:PRESet

Attribute

Summary

Preset State: none

*RST State: none

SCPI Compliance: standard

Command Only

Description

The PRESet command is defined by SCPI to affect the enable register.

If you want to clear all event registers and queues, use the *CLS com-

mand.

Table 4-18. Preset Values

Status Node

Preset Value

Operation enable register

Questionable enable register

PTRansition filters

32767

NTRansition filters

Example

OUTPUT 720;”:STATUS:PRESET”

4-96

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Programming Commands

SYSTem Subsystem

The commands in this subsystem have the following command hierar-

chy:

:SYSTem

:ERRor?

:HELP

:HEADers?

:PRESet

:VERSion?

4-97

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Programming Commands

SYSTem Subsystem

ERRor

Queries an error from the error queue.

Syntax

:SYSTem:ERRor?

Attribute

Summary

Preset State: none

*RST State: none

SCPI Compliance: standard

Query Only

Description

The Agilent 86120C has a 30 entry error queue. The queue is a first-

in, first- out buffer. Repeatedly sending the query :SYSTEM:ERROR?

returns the error numbers and descriptions in the order in which they

occur until the queue is empty. Any further queries returns +0, “No

errors” until another error occurs.

For a complete list of error messages, refer to “Error Messages” on

page 7- 11.

Query Response

Example

<value> is an integer. <string> is the text of the error message. The

following is an example of a response:

-113,”Undefined header”

DIM Error$[250]

OUTPUT 720;”:SYSTEM:ERROR?”

ENTER 720;Error$

PRINT Error$

4-98

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Programming Commands

SYSTem Subsystem

HELP:HEADers?

Queries a listing of all the remote p rogramming commands available

for the Agilent 86120C.

Syntax

:SYSTem:HELP:HEADers?

Attribute

Summary

Preset State: none

*RST State: none

SCPI Comp liance: instrument sp ecific

Query Only

Description

The returned ASCII string of commands is in the IEEE 488.2 arbitrary-

block data format. The first line indicates the total number of bytes

returned to the comp uter. That is, the # character is followed by one

digit which indicates how many of the following digits convey the byte

count. The next digits give the actual byte count. For examp le, in the

listing below, 4387 bytes are indicated in the file.

Each command in the listing is sep arated by a linefeed character.

The following is an example of the first few lines and last few lines

returned in the string. The term nquery indicates that a command

cannot be sent as a query. The term qonly indicates that a command

can only be sent as a query.

#44387

:ABORt/nquery/

:CALCulate:DATA?/qonly/

:CALCulate:TRANsform:FREQuency:POINts

:CALCulate1:DATA?/qonly/

:CALCulate1:TRANsform:FREQuency:POINts

:CALCulate2:DATA?/qonly/

*IDN?/qonly/

*OPC

*RCL/nquery/

*RST/nquery/

*SAV/nquery/

*SRE

*STB?/qonly/

*TRG/nquery/

*TST?/qonly/

*WAI/nquery/

4-99

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Programming Commands

SYSTem Subsystem

PRESet

Performs the equivalent of p ressing the front- p anel PRESET key.

Syntax

:SYSTem:PRESet

Attribute

Summary

Preset State: none

*RST State: none

SCPI Compliance: standard

Command Only

Description

The instrument state is set according to the settings shown in the fol-

lowing table.

Table 4-19. Instrument Conditions (1 of 2)

Settings after Preset

Key Pressed

Settings after Power

Turned On

Item

last state^a

last state

off

Display mode

single wavelength

Wavelength range limiting

Start wavelength

Stop wavelength

1270 nm

1650 nm

off

Graphical display

Measurement acquisition

Wavelength calibration

Elevation correction value

Wavelength units

Amplitude units

continuous

vacuum

not affected

last state

dBm

Power offset

0 dB

Peak threshold

10 dB

Peak excursion

15 dB

4-100

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Programming Commands

SYSTem Subsystem

Table 4-19. Instrument Conditions (2 of 2)

Settings after Preset

Key Pressed

Settings after Power

Turned On

Item

Measurement speed

Measurement bandwidth

Drift measurements

Fabry-Perot laser measurements

Delta measurements:

∆ power

normal

narrowband

off

last state

narrowband

off

∆ wavelength

off

∆ wavelength and power

reference signal position

Signal-to-noise measurements

measurement

1270 nm

off

wavelength reference

user wavelength

auto

last state

not affected

100

number of averages

GPIB address

not affected

Power-bar display

a. The term “last state” refers to the last setting that this parameter was in before the instrument power was

turned off.

4-101

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Programming Commands

SYSTem Subsystem

VERSion

Queries the version of SCPI that the Agilent 86120C comp lies with.

Syntax

:SYSTem:VERSion

Attribute

Summary

Preset State: none

*RST State: none

SCPI Compliance: standard

Query Only

Description

The SCPI version used in the Agilent 86120C is 1995.0.

Table 4-20. SCPI Version Numbers

SCPI Version

1995.0

Instrument Serial Prefix

US3545 and above

4-102

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Programming Commands

TRIGger Subsystem

The SCPI definition defines the TRIGger subsystem to include ABORt,

ARM, INITiate, and TRIGger commands. The Agilent 86120C has no

ARM or TRIGger commands.

The commands in this subsystem have the following command hierar-

chy:

ABORt

INITiate

:CONTinuous

[:IMMediate]

4-103

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ABORt

Halts the current measurement sequence and places the instrument in

the idle state.

Syntax

:ABORt

Attribute

Summary

Preset State: not affected

SCPI Compliance: standard

Command Only

Description

If the instrument is configured for continuous measurements, a new

measurement sequence will begin. Otherwise, the instrument stays in

the idle state until a new measurement is initiated.

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Programming Commands

TRIGger Subsystem

INITiate:CONTinuous

Selects single or continuous measurement acquisition.

Syntax

:INITiate:CONTinuous{?| {ON | OFF | 1 | 0}}

Attribute

Summary

Non- sequential command

Preset State: on

*RST State: off

SCPI Compliance: standard

Description

When on is sp ecified, the instrument continuously measures the input

spectrum.

Non-sequential command

Always use an *OPC? query or a *WAI command to ensure that this command has

the time to complete before sending any more commands to the instrument. Refer

to “Always force the Agilent 86120C to wait for non-sequential commands” on

page 3-12 for more information.

4-105

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Programming Commands

TRIGger Subsystem

INITiate[:IMMediate]

Initiates a new measurement sequence.

:INITiate:IMMediate

Syntax

Attribute

Summary

Non- sequential command

Preset State: none

SCPI Compliance: standard

Command Only

Non-sequential command

Always use an *OPC? query or a *WAI command to ensure that this command has

the time to complete before sending any more commands to the instrument. Refer

to “Always force the Agilent 86120C to wait for non-sequential commands” on

page 3-12 for more information.

4-106

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Programming Commands

UNIT Subsystem

The only command provided in this subsystem is the POWer command

as shown in the following command hierarchy:

:UNIT

[:POWer]

Sets the p ower units to watts (linear) or dBm (logarithmic).

:UNIT[:POWer]{?| {W | DBM}}

Syntax

Attribute

Summary

Preset State: dBm

*RST State: dBm

SCPI Compliance: standard

4-107

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Programming Commands

UNIT Subsystem

4-108

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Test 1. Absolute Wavelength Accuracy 5- 3

Test 2. Sensitivity 5- 4

Test 3. Polarization Dep endence 5- 5

Test 4. Op tical Inp ut Return Loss 5- 6

Test 5. Amplitude Accuracy and Linearity 5- 9

Performance Tests

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Performance Tests

The procedures in this chapter test the Agilent 86120C’s performance

using the specifications listed in Chapter 6, “Specifications and Regula-

tory Information” as the p erformance standard. All of the tests are

done manually without the aid of a comp uter. None of these tests

require access to the interior of the instrument.

Test 1. Absolute Wavelength Accuracy 5- 3

Test 2. Sensitivity 5- 4

Test 3. Polarization Dep endence 5- 5

Test 4. Op tical Inp ut Return Loss 5- 6

Test 5. Amplitude Accuracy and Linearity 5- 9

Allow the Agilent 86120C to warm up for 15 minutes before doing any

of the p erformance tests.

Calibration Cycle

This instrument requires periodic verification of performance. The

instrument should have a complete verification of specifications once

every two years.

5-2

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Performance Tests

Test 1. Absolute Wavelength Accuracy

Description

Wavelength accuracy is verified using traceable light sources such as

the following devices:

• Stable lasers

• Gas lamps

• HeNe gas lasers

C A U T IO N

Do not exceed +18 dBm source power. The Agilent 86120C’s input circuitry can

be damaged when total input power exceeds 18 dBm.

Procedure

Use three or four light standards that cover the Agilent 86120C’s

wavelength range. Connect the traceable sources to the Agilent 86120C

and verify that the Agilent 86120C is reading the sources to within the

absolute wavelength accuracy specification.

5-3

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Performance Tests

Test 2. Sensitivity

Description

Sensitivity is verified using the following devices:

• Optical power meter

• Optical attenuator

• 1310 nm and 1550 nm lasers (>0 dBm output power)

C A U T IO N

Do not exceed +18 dBm source power. The Agilent 86120C’s input circuitry can

be damaged when total input power exceeds 18 dBm.

Procedure

Perform the following p rocedure first using the 1310 nm laser and

then repeat the steps using the 1550 nm laser.

1 Connect the laser’s output to the optical attenuator’s input.

2 Connect the optical attenuator’s output to the optical power meter.

3 Adjust the attenuator for a reading of 0 dBm on the p ower meter.

Record the attenuator’s setting.

Attenuation at 0 dBm: ____________

4 Adjust the attenuator for a reading of –35 dBm on the p ower meter.

Record the attenuator’s setting.

Attenuation at –35 dBm: ____________

5 Disconnect the fiber-optic cable at the power meter’s input and connect

the cable to the Agilent 86120C being tested.

6 Reset the optical attenuator to the setting recorded in Step 3.

7 Read the p ower and wavelength measured on the Agilent 86120C, and

compare them to the specifications listed in Chapter 6, “Specifications

and Regulatory Information”.

8 Reset the optical attenuator to the setting recorded in Step 4.

9 Read the p ower and wavelength measured on the Agilent 86120C, and

compare them to the specifications listed in Chapter 6, “Specifications

and Regulatory Information”.

5-4

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Performance Tests

Test 3. Polarization Dependence

Description

Polarization Dependence is verified using the following devices:

• 1310 nm and 1550 nm DFB lasers

• Optical attenuator

• Agilent 11896A polarization controller

C A U T IO N

Do not exceed +18 dBm source power. The Agilent 86120C’s input circuitry can

be damaged when total input power exceeds 18 dBm.

Procedure

Perform the following p rocedure first using the 1310 nm laser and

then repeat the steps using the 1550 nm laser.

1 Turn on the lasers and allow them to warm up .

2 Set the polarization controller to a scan rate of 5.

3 On the Agilent 86120C, press the Preset key.

4 Connect the laser’s optical output to the polarization controller’s optical

input.

5 Connect the polarization controller’s optical output to the

Agilent 86120C being tested.

6 Set the polarization controller to autoscan.

7 On the Agilent 86120C, press Peak WL, Appl’s, and then DRIFT. Press

MAX-MIN so that both MAX and MIN in the softkey label are highlighted.

The display shows the total drift since the drift measurement was

started.

8 Wait five minutes, read the peak amplitude drift from the

Agilent 86120C, and compare with the specification listed in Chapter 6,

“Specifications and Regulatory Information”.

5-5

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Performance Tests

Test 4. Optical Input Return Loss

Description

Procedure

Inp ut return loss is verified using the following devices:

• Agilent 8153A lightwave multimeter

• Agilent 81553SM 1550 nm Fabry- Perot laser, SM 9/125 µm source

module

• Agilent 81534A return loss module

Standard instruments (flat contacting connectors)

1 Turn the source module’s outp ut off.

2 Connect a single-mode patchcord between the source module’s optical

outp ut and the return loss module’s INPUT SOURCE connector.

3 Set the return loss module’s wavelength to 1550 nm, and select an

average time of 1 second.

4 Locate an HMS- 10/HRL to FC/PC patchcord. Connect the HMS- 10/HRL

end of the patchcord to the return loss module’s OUTPUT connector.

Terminate the other end of the cable.

5 Zero the return loss module.

6 Turn on the source module.

7 Remove the termination from the cable, and leave the cable’s free end

uncovered.

8 The return loss module measures the reflection reference (14.6 dB

return loss of the p atchcord’s FC/PC connector in air).

9 Make a low- reflection termination in the HMS-10/HRL to FC/PC

p atchcord. Do this by wrap p ing the cable 6 times around a 5 mm

diameter mandrel.

10 The return loss module measures the termination parameter.

11 Connect the HMS- 10/HRL to FC/PC p atchcord to the Agilent 86120C’s

front panel OPTICAL INPUT connector.

12 The lightwave multimeter measures the return loss. Compare this

measurement with the specification listed in Chapter 6, “Specifications

5-6

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Performance Tests

Test 4. Optical Input Return Loss

and Regulatory Information”.

Procedure

Option 022 instruments (angled contacting connectors)

1 Turn the source module’s outp ut off.

2 Connect a single-mode patchcord between the source module’s optical

outp ut and the return loss module’s INPUT SOURCE connector.

3 Set the return loss module’s wavelength to 1550 nm, and select an

average time of 1 second.

4 Locate an HMS- 10/HRL to FC/APC (angled FC) patchcord. Connect the

HMS- 10/HRL end of the patchcord to the return loss module’s OUTPUT

connector. Terminate the FC/APC end of the cable.

5 Zero the return loss module.

6 Turn on the source module.

7 Remove the termination from the cable, and connect the FC/APC end

of an FC/APC to FC/PC cable to the free end of this cable. Leave the

cable’s free end uncovered.

8 The return loss module measures the reflection reference (14.6 dB

return loss of the p atchcord’s FC/PC connector in air).

9 Disconnect the FC/APC to FC/PC cable.

10 Make a low- reflection termination in the HMS-10/HRL to FC/APC

p atchcord. Do this by wrap p ing the cable 6 times around a 5 mm

diameter mandrel.

11 The return loss module measures the termination parameter.

12 Connect the HMS- 10/HRL to FC/APC patchcord to the Agilent 86120C’s

front panel OPTICAL INPUT connector.

13 The lightwave multimeter measures the return loss. Compare this

measurement with the specification listed in Chapter 6, “Specifications

and Regulatory Information”.

5-7

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Performance Tests

Test 4. Optical Input Return Loss

FC/APC patchcord loss

The effect of having loss in the FC/APC patchcord 1 to 2 connector pair is to under

measure the return loss by twice the FC/APC patchcord 1 to 2 loss. For example, if

this connector pair loss is 0.5 dB, then the actual return loss caused by the 14.6 dB

Fresnel reflection is 15.6 dB, but we enter 14.6 dB as an R value. Then, if the

device under test return loss is exactly 40 dB below that of the 14.6 dB Fresnel

reflection, the optical return loss module will display 53.6 dB because the 0.5 dB

connector pair loss (seen twice) is removed. In reality, the return loss is 54.6 dB

(exactly 40 dB below 14.6 dB), better than that displayed.

5-8

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Performance Tests

Test 5. Amplitude Accuracy and Linearity

Equipment

Procedure

Amp litude linearity is p erformed using the following devices:

• 1550 nm DFB lasers

• Optical attenuator

• Agilent 11896A polarization controller

• Optical power meter

Polarization sensitivity

To ensure measurement accuracy, minimize the movement of any fiber-optic

cables during this procedure. Moving cables causes polarization changes which

affect amplitude measurements.

1 Turn on the laser and allow it to warm up.

2 Connect the laser’s output to the optical attenuator’s input.

3 Connect the op tical attenuator’s outp ut to the p olarization controller’s

optical input.

4 Connect the polarization controller’s optical output to the optical power

meter.

5 Configure the optical power meter for 1550 nm.

6 Adjust the optical attenuator so that the power meter measures a power

level of 0 dBm.

7 Enter the attenuator setting and the measured power level in the first

row of Table 5- 21onp age 5- 11 . Be sure to enter these values into the

“Attenuator Settings” and “Power Meter Readings” columns.

8 Enter the measured power on the following line:

Pwr: ____________

9 Change the attenuator in 1 dB steps as shown in Table 5- 21, and enter

the attenuator settings and power measurements.

After completing this step, the first two columns of the table should be

5-9

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Performance Tests

Test 5. Amplitude Accuracy and Linearity

completely filled in.

10 Disconnect the fiber- op tic cable from the op tical p ower meter and

connect it to the Agilent 86120C’s OPTICAL INPUT connector.

11 Set the optical attenuator for the value that you recorded in Step 8.

12 Place the polarization controller in the auto scan mode.

13 Press the Agilent 86120C’s front- panel Preset key.

14 Press List by Power, Appl’s, and then DRIFT.

15 After two minutes, stop the polarization controller’s auto scan function.

16 Press the MAX-MIN softkey so that MAX is highlighted. Enter the

maximum drift reading on the following line:

maximum drift: ____________

17 Press the MAX-MIN softkey so that MIN is highlighted. Enter the

minimum drift reading on the following line:

minimum drift: ____________

18 Use the values recorded in Step 8, Step 16, and Step 17 to calculate the

p ower- correction offset value as shown in the following equation:

minimum drift + maximum drift

---------------------------------------------------------------------------

offset =

– Pwr

Enter the calculate value on the following line:

power- correction offset: ____________

19 Change the attenuator to the settings shown in Table 5- 21. For each

setting, record the p ower measured on the Agilent 86120C.

After completing this step, the table’s column titled “Agilent 86120C

Power Reading” should be completely filled in.

20 Calculate the “Linearity” value for each row in the table using the

following equation:

Linearity = Power Meter Reading – 86120C Power Reading – offset

21 Compare the linearity values with the specification listed in Chapter 6,

“Specifications and Regulatory Information”. The data may show

multiple amplitude plateaus separated by small amplitude steps. This is

not a p roblem as long as the amp litude step s are within the linearity

specification.

5-10

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Performance Tests

Test 5. Amplitude Accuracy and Linearity

Table 5-21. Linearity Data Values

Desired Power

Power Meter

Reading

Agilent 86120C

Linearity

Attenuator Setting

(dBm)

Power Reading

–1

–2

–3

–4

–5

–6

–7

–8

–9

–10

–11

–12

–13

–14

–15

–16

–17

–18

–19

–20

5-11

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Definition of Terms 6- 3

Specifications—NORMAL Update Mode 6- 5

Specifications—FAST Update Mode 6- 8

Operating Specifications 6- 11

Laser Safety Information 6- 12

Comp liance with Canadian EMC Requirements 6- 13

Declaration of Conformity 6-14

Product Overview 6- 15

Specifications and Regulatory

Information

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Specifications and Regulatory Information

Specifications and Regulatory

Information

This chapter lists specification and characteristics of the instrument. The dis-

tinction between these terms is described as follows:

• Specifications describe warranted performance over the temperature

range 0°C to +55°C and relative humidity <95% (unless otherwise noted).

All specifications apply after the instrument’s temperature has been sta-

bilized after 15 minutes of continuous operation.

• Characteristics provide useful information by giving functional, but

nonwarranted, performance parameters. Characteristics are printed in

italics.

Calibration Cycle

This instrument requires periodic verification of performance. The instrument

should have a complete verification of specifications once every two years.

6-2

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Specifications and Regulatory Information

Definition of Terms

Wavelength

Range refers to the allowable wavelength range of the optical input signal.

Absolute accuracy indicates the maximum wavelength error over the allowed

environmental conditions. The wavelength accuracy is based on fundamental

physical constants, which are absolute standards not requiring traceability to

artifacts kept at national standards laboratories. Two He-Ne gas lasers are

used. First, there is an internal 632.991 nm-vacuum (473.6127 THz) reference

laser¹. To verify absolute wavelength accuracy, an external laser is measured

during manufacturing at 1523.488 nm, or 196.7804 THz².

Differential Accuracy indicates the maximum wavelength error in measuring

the wavelength difference between two signals that are simultaneously

present.

Minimum Resolvable Separation indicates the minimum wavelength separa-

tion of two laser lines required to measure each wavelength simultaneously.

Two laser lines closer in wavelength than the minimum resolvable separation

are not resolved and one average wavelength is displayed.

Display Resolution indicates the minimum incremental change in displayed

wavelength.

Amplitude

Calibration Accuracy indicates the maximum power calibration error at the

specified wavelengths over the allowed environmental conditions. The ampli-

tude calibration accuracy is traceable to a National Institute of Standards and

Technology (NIST) calibrated optical power meter. NIST is the national stan-

dards laboratory of the United States.

Flatness refers to the maximum amplitude error in a measurement between

two lines that are separated in wavelength by no more than the specified

amount.

Linearity indicates the maximum power error in measuring the change in power

1. Obarski, G. E. 1990. “Wavelength Measurement System for Optical Fiber Communications” NIST

Technical Note 1336 (February): 18. Take the average of the two frequencies straddling gain center.

2. D. A. Jennings, F. R. Peterson, and K. M. Evenson. 1979. “Frequency measurement of the 260-THz

(1.15 micron) He-Ne laser” Optics Letters Vol. 4, No. 5 (May): 129-130.

6-3

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Specifications and Regulatory Information

Definition of Terms

of one laser line.

Polarization Dependence indicates the maximum displayed power variation as

the polarization of the input signal is varied.

Display Resolution indicates the minimum incremental change in displayed

power.

Sensitivity

Sensitivity is defined as the minimum power level of a single laser-line input to

measure wavelength and power accurately. A laser line with less than the min-

imum power may be measured but with reduced wavelength and power accu-

racy. For multiple laser-lines input, sensitivity may be limited by total input

power.

Selectivity

Selectivity indicates the ability to measure the wavelength and power of a

weak laser line in the proximity of a specified stronger laser line and separated

by the specified amount.

Input Power

Maximum displayed level indicates the maximum total input power (total of all

laser lines present) to accurately measure wavelength and power.

Maximum safe input power indicates the maximum total input power (total of

all laser lines present) to avoid permanent optical damage to the instrument.

Maximum Number Maximum number of lines input is the maximum number of displayed lines. If

of Lines Input

more than 200 lines are input, only the 200 longest wavelength lines are dis-

played.

Input Return Loss Input Return Loss indicates the optical power reflected back to the user’s fiber

cable relative to the input power. It is limited by the return loss of the front-

panel connector, and assumes the user’s connector is good.

Measurement

Cycle Time

Measurement cycle time refers to the cycle time when measuring wavelength

and power of laser lines. Specific advanced applications may require longer

cycle times.

6-4

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Specifications and Regulatory Information

Specifications—NORMAL Update Mode

Each laser line is assumed to have a linewidth (including modulation side-

bands) of less than 5 GHz.

All specifications apply when the instrument is in the following modes:

• NORMAL up date mode unless noted. Refer to “Measurement rate” on

page 2- 13.

• Configured to measure narrowband devices. Specifications do not apply

when the instrument is configured to measure broadband devices. Refer

to “Measuring broadband devices and chirp ed lasers” on page 2- 9 .

Wavelength

Range

1270–1650

Absolute accuracy (lines separated by ≥15 GHz)

2 ppm ( 0.003 nm at 1550 nm and 1310 nm)

Differential accuracy (characteristic)

1 ppm

Minimum resolvable separation^a(characteristic)

10 GHz (0.08 nm at 1550 nm, 0.06 nm at 1300 nm)

Display resolution

0.001 nm

a. Signals of equal amplitude. For lines that are separated by less than 30 GHz, wavelength accuracy is reduced.

6-5

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Specifications and Regulatory Information

Specifications—NORMAL Update Mode

Amplitude

Calibration accuracy at calibration wavelengths

Flatness, 30 nm from any wavelength

0.5 dB (at 1310 and 1550 nm 30 nm)

1270-1600 nm (characteristic)

1270-1650 nm (characteristic)

0.2 dB

0.5 dB

0.3 dB

Linearity, 1270 nm to 1600 nm, lines above –30 dBm

Polarization dependence

1270-1600 nm

0.5 dB

1.0 dB

1600-1650 nm (characteristic)

Display resolution

0.01 dB

Sensitivity

1270-1600 nm, single line input

–40 dBm

–30 dBm

1600-1650 nm, single line input

1270-1650 nm, multiple lines input (characteristic)

30 dB below total input power, but not less than

single line input sensitivity.

Selectivity

25 dB

10 dB

Two lines input separated by ≥50 GHz (characteristic)

Two lines input separated by ≥15 GHz (characteristic)

Input Power

+10 dBm

+18 dBm

200

Maximum displayed level (sum of all lines)

Maximum safe input level (sum of all lines)

Maximum Number of Laser Lines Input

6-6

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Specifications and Regulatory Information

Specifications—NORMAL Update Mode

Input Return Loss

With straight contactconnectors

35 dB

With angled contact connectors (Option 022)

50 dB

Measurement Cycle Time

Normal update mode (characteristic)

1.0 s (1 measurement-per-second)

Measurement Applications

Signal-to-Noise Ratio (characteristic) ^a

channel spacing ≥100 GHz

>35 dB

>27 dB

channel spacing ≥50 GHz

Signal-to-Noise Ratio with Averaging, modulated lasers (characteristic) ^a

>35 dB with 100 averages

>27 dB with 100 averages

channel spacing ≥100 GHz

channel spacing ≥50 GHz

a. 0.1 nm noise bandwidth, lines above –25 dBm.

6-7

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Specifications and Regulatory Information

Specifications—FAST Update Mode

Each laser line is assumed to have a linewidth (including modulation side-

bands) of less than 10 GHz.

All specifications apply when the instrument is in the following modes:

• FAST up date mode unless noted. Refer to “Measurement rate” on

page 2- 13.

• Configured to measure narrowband devices. Specifications do not apply

when the instrument is configured to measure broadband devices. Refer

to “Measuring broadband devices and chirp ed lasers” on page 2- 9 .

Wavelength

Range

1270–1650

Absolute accuracy (lines separated by ≥30 GHz)

3 ppm ( 0.005 nm at 1550 nm, 0.004 nm at 1310 nm)

Differential accuracy (characteristic)

2 ppm

Minimum resolvable separation^a(characteristic)

20 GHz (0.16 nm at 1550 nm, 0.11 nm at 1300 nm)

Display resolution

0.001 nm

a. Signals of equal amplitude. For lines that are separated by less than 30 GHz, wavelength accuracy is reduced.

6-8

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Specifications and Regulatory Information

Specifications—FAST Update Mode

Amplitude

Calibration accuracy at calibration wavelengths

Flatness, 30 nm from any wavelength

0.5 dB (at 1310 and 1550 nm 30 nm)

1270-1600 nm (characteristic)

1270-1650 nm (characteristic)

0.2 dB

0.5 dB

0.3 dB

Linearity, 1270 nm to 1600 nm, lines above –30 dBm

Polarization dependence

1270-1600 nm

0.5 dB

1.0 dB

1600-1650 nm (characteristic)

Display resolution

0.01 dB

Sensitivity

1270-1600 nm, single line input

–40 dBm

–30 dBm

1600-1650 nm, single line input

1270-1650 nm, multiple lines input (characteristic)

30 dB below total input power, but not less than

single line input sensitivity.

Selectivity

25 dB

10 dB

Two lines input separated by ≥100 GHz (characteristic)

Two lines input separated by ≥30 GHz (characteristic)

Input Power

+10 dBm

+18 dBm

200

Maximum displayed level (sum of all lines)

Maximum safe input level (sum of all lines)

Maximum Number of Laser Lines Input

6-9

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Specifications and Regulatory Information

Specifications—FAST Update Mode

Input Return Loss

With flat contacting connectors

35 dB

50 dB

With angled contacting connectors (Option 022)

Measurement Cycle Time

Fast update mode (characteristic)

0.5 s (2 measurements-per-second)

Measurement Applications

Signal-to-Noise Ratio (characteristic) ^a

channel spacing ≥200 GHz

>35 dB

>27 dB

channel spacing ≥100 GHz

Signal-to-Noise Ratio with Averaging, modulated lasers

(characteristic) ^a

>35 dB with 100 averages

>27 dB with 100 averages

channel spacing ≥200 GHz

channel spacing ≥100 GHz

a. 0.1 nm noise bandwidth, lines above –25 dBm.

6-10

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Specifications and Regulatory Information

Operating Specifications

Use

indoor

Power:

70 W max

Voltage

100 / 115 / 230 / 240 V ~

50 / 60 Hz

Frequency

Altitude

Up to 2000 m (~ 6600 ft)

0°C to +55°C

Operating temperature

Maximum relative humidity

80% for temperatures up to 31°C decreasing linearly to 50% relative

humidity at 40°C

Weight

8.5 kg (19 lb)

Dimensions (H × W × D)

140 × 340 × 465 mm (5.5 × 13.4 × 18.3 in)

6-11

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Specifications and Regulatory Information

Laser Safety Information

The light sources specified by this user guide are classified according to

IEC 60825-1 (2001).

The light sources comply with 21 CFR 1040.10 except for deviations pursuant to

Laser Notice No. 50, dated 2001-July-26.

Laser Safety

Laser type

LED

1200-1650nm

1 nW

Wavelength

Max. CW output power *

Beam waist diameter

10 µm

0.1

Numeric aperture

Laser class according to IEC 60825-1 (2001)

Max. permissible CW output power**

10 mW

* Max. CW output power means the highest possible optical CW power that the laser source can

produce at its output.

** Max. permissible CW output power is the highest optical power that is permitted within the

appropriate IEC laser class.

WA R N IN G

Please pay attention to the following laser safety warnings:

• Under no circumstances look into the end of an optical cable attached

to the optical output when the device is operational. The laser radiation

can seriously damage your eyesight.

• Do not enable the laser when there is no fiber attached to the optical

output connector.

• Pressing the "active" button enables the laser. The laser is on when the

green LED is lit.

• The use of op tical instruments with this p roduct will increase eye haz-

ard.

• Refer servicing only to qualified and authorized p ersonnel.

6-12

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Specifications and Regulatory Information

Compliance with Canadian EMC Requirements

Compliance with Canadian EMC

Requirements

This ISM device complies with Canadian ICES-001.

Cet appareil ISM est conforme à la norme NMB-001 du Canada.

Notice for Germany: Noise Declaration

Acoustic Noise Emission

LpA < 70 dB

Geräuschemission

LpA < 70 dB

Operator position

Normal position

per ISO 7779

am Arbeitsplatz

normaler Betrieb

nach DIN 45635-1

6-13

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Specifications and Regulatory Information

Declaration of Conformity

6-14

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Specifications and Regulatory Information

Product Overview

Front view of instrument

Rear view of instrument

6-15

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Specifications and Regulatory Information

Product Overview

6-16

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Instrument Preset Conditions 7-2

Menu Maps 7-4

Error Messages 7-11

Front-Panel Fiber-Optic Adapters 7-17

Power Cords 7-18

Agilent Technologies Service Offices 7-18

Reference

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Reference

Instrument Preset Conditions

Table 5-22. Instrument Preset Conditions (1 of 2)

Settings after Preset

Key Pressed

Settings after Power

Turned On

Item

last state^a

last state

off

Display mode

single wavelength

Wavelength range limiting

Start wavelength

Stop wavelength

1270 nm

1650 nm

off

Graphical display

Measurement acquisition

Wavelength calibration

Elevation correction value

Wavelength units

Amplitude units

continuous

vacuum

not affected

last state

dBm

Power offset

0 dB

Peak threshold

10 dB

Peak excursion

15 dB

Measurement speed

normal

7-2

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Reference

Instrument Preset Conditions

Table 5-22. Instrument Preset Conditions (2 of 2)

Settings after Preset

Key Pressed

Settings after Power

Turned On

Item

Device bandwidth

narrowband

last state

off

Drift measurements

Fabry-Perot laser measurements

Delta measurements:

∆ power

off

∆ wavelength

off

∆ wavelength and power

reference signal position

Signal-to-noise measurements

measurement

1270 nm

off

wavelength reference

user wavelength

auto

last state

not affected

100

number of averages

GPIB address

not affected

Power-bar display

a. The term “last state” refers to the last setting that this parameter was in before the instrument

power was turned off.

7-3

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Reference

Menu Maps

This section provides menu maps for the Agilent 86120C softkeys. The maps show

which softkeys are displayed after pressing a front-panel key; they show the relation-

ship between softkeys. The softkeys in these maps are aligned vertically instead of

horizontally as on the actual display. This was done to conserve space and to make the

maps easier to interpret.

7-4

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Reference

Menu Maps

Appl’s Menu

7-5

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Reference

Menu Maps

Display Avg WL Menu

There is no menu associated with this key.

Measurement Cont Menu

There is no menu associated with this key.

Display List by Power Menu

7-6

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Reference

Menu Maps

Display List by WL Menu

Delta On Menu

7-7

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Reference

Menu Maps

Delta Off Menu

Display Peak WL and System Preset Menus

Measurement Single Menu

There is no menu associated with this key.

7-8

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Reference

Menu Maps

System Print Menu

7-9

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Reference

Menu Maps

System Setup Menu

7-10

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Reference

Error Messages

In this section, you’ll find all the error messages that the Agilent 86120C can display on

its screen. Table 5-23 on page 7-11 lists all instrument-specific errors. Table 5-24 on

page 7-14 lists general SCPI errors.

Table 5-23. Instrument Specific Error Messages (1 of 3)

Error Number

Error Message

BAD CHECKSUM FROM MOTOR

MOTOR COMMUNICATION PROBLEM

MOTOR NOT MOVING

MOTOR INDEX PULSE NOT FOUND

MOTOR CHIP SET INIT FAILED

MOTOR COMMUTATION FAILURE

MOTOR NOT SETTLED

MOTOR DID NOT STOP

MOTOR MOTION ERROR

MOTOR POSITION LIMIT FAILED

MOTOR POSITION WRAP FAILED

POWER LEVEL TOO HIGH

DATA DOWNLOAD PROBLEM

DATA ACQUISITION PROBLEM

MAX NUMBER OF SIGNALS FOUND

MOTOR INTERRUPT RECEIVED

7-11

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Reference

Error Messages

Table 5-23. Instrument Specific Error Messages (2 of 3)

Error Number

Error Message

ROM BYTE UNERASED

ROM WRITE OPERATION FAILED

ROM DEFECTIVE

ROM DATA INVALID

ROM VERSION INCOMPATIBLE

ROM POLLING LIMITED OUT

INPUT OUT OF RANGE

BAD CAL ROM DATA

NVSRAM WRITE OPERATION FAILED

SOFTWARE INITIALIZATION FAIL

HARDWARE INITIALIZATION FAIL

INITIALIZATION TIMEOUT

BATTERY FAILED

TOO MANY ERRORS

FUNCTION NOT YET IMPLEMENTED

PRINTER OFF LINE

PRINTER OUT OF PAPER

PRINTER ERROR DETECTED

PRINTER TIMED OUT

7-12

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Reference

Error Messages

Table 5-23. Instrument Specific Error Messages (3 of 3)

Error Number

Error Message

PRINTOUT WAS ABORTED

NOT ALLOWED IN FABRY PEROT

NOT ALLOWED IN S/N

UNKNOWN KEYPRESS

NUM LINES < NUM REFS

NUM LINES > NUM REFS

NO REFERENCE SIGNAL

GAIN RANGING ERROR

INCOMPATIBLE HARDWARE

UNKNOWN ERROR

7-13

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Reference

Error Messages

Table 5-24. General SCPI Error Messages (1 of 3)

Error Number

Description

“No errors”

–100

–101

–102

–103

–104

–105

–108

–109

–112

–113

–120

–121

–123

–124

–128

–131

–134

–138

–141

–148

–150

–151

“Command error (unknown command)“

“Invalid character“

“Syntax error“

“Invalid separator“

“Data type error“

“GET not allowed“

“Parameter not allowed“

“Missing parameter“

“Program mnemonic too long“

“Undefined header“

“Numeric data error”

“Invalid character in number“

“Exponent too large“

“Too many digits“

“Numeric data not allowed“

“Invalid suffix“

“Suffix too long”

“Suffix not allowed“

“Invalid character data“

“Character data not allowed“

“String data error“

“Invalid string data“

7-14

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Reference

Error Messages

Table 5-24. General SCPI Error Messages (2 of 3)

Error Number

Description

–158

–161

–168

–170

–171

–178

–200

–211

“String data not allowed“

“Invalid block data“

“Block data not allowed“

“Expression error“

“Invalid expression“

“Expression data not allowed“

“Execution error“

“Trigger ignored”

Caused by sending the *TRG command when the instrument is already

taking a measurement or when the instrument is in continuous

measurement mode.

–213

–221

“Init ignored”

Caused by sending an INIT:IMM, READ, or MEASure command while a

measurement is already in progress or while the instrument is in

continuous measurement mode.

“Settings conflict”

Caused by trying to set the instrument to a state that is not allowed. For

example, turning on drift maximum and drift minimum state

simultaneously or turning on SNR state while drift or delta state is on.

–222

–223

–224

– 230

“Data out of range“

“Too much data“

“Illegal parameter value”

“Data corrupt or stale”

Caused by trying to query measurement data immediately after a *RST

command. For example, sending *RST; FETCh or sending *RST;

:CALC2:DATA? pow.

–232

–273

“Data questionable”

Caused by sending a resolution value in one of the measurement

functions that is outside the instrument’s range.

“Illegal macro label”

7-15

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Reference

Error Messages

Table 5-24. General SCPI Error Messages (3 of 3)

Error Number

Description

–310

–321

–350

–400

–410

–420

–430

–440

“System error“

“Out of memory”

“Too many errors“

“Query error“

“Query INTERRUPTED“

“Query UNTERMINATED“

“Query DEADLOCKED“

“Query UNTERMINATED after indef resp“

Query was unterminated after an indefinite response.

7-16

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Reference

Front-Panel Fiber-Optic Adapters

Front Panel

Fiber-Optic Adapter

Description

Agilent Part Number

Diamond HMS-10

81000AI

FC/PC^a

81000FI

81000GI

81000KI

81000SI

81000VI

81000WI

DIN

Biconic

a. The FC/PC is the default front-panel optical connector.

Dust Covers

Agilent Part Number

FC connector

1005-0594

1005-0593

1005-0595

1005-0596

1005-0597

Diamond HMS-10 connector

DIN connector

ST connector

SC connector

7-17

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Reference

Power Cords

Cable Part

No.

Plug Type

Country

250V

8120-1351

United Kingdom, Cyprus, Nigeria, Zimbabwe,

Singapore

250V

125V

250V

8120-1369

8120-1689

8120-1378

8120-2104

Australia, New Zealand, China

East and West Europe, Saudi Arabia, So. Africa,

India (unpolarized in many nations)

United States, Canada, Mexico, Philippines,

Taiwan

Switzerland

220V

250V

8120-3997

8120-4211

Denmark

Republic of South Africa, India

100V

8120-4753

Japan

8120-5182

8120-6868

8120-6979

8120-8376

8120-8871

Israel

Argentinia

Chile

China

Brazil, Thailand

* Part number shown for plug is the industry identifier for the plug

only. Number shown for cable is the Agilent Technologies part

number for the complete cable including the plug.

Agilent Technologies Service Offices

7-18

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Reference

Agilent Technologies Service Offices

Before returning an instrument for service, call the Agilent Technologies Instrument

Support Center at +1 (877) 447 7278, visit the Test and Measurement Web Sites by

Country page at http://www.agilent.com/comms/techsupport, select your country

and enter the “Technical Support” link, or call one of the numbers listed below.

Agilent Technologies Service Numbers

Austria

0820 87 44 11

Belgium

Brazil

+32 (0) 2 404 9340

+11 7297-8600

800 810 0508

China

Denmark

Finland

+45 70 131515

+358 (0) 10 855 2100

0825 010 700

France

Germany

India

01805 24 6337

1600 112 626

Italy

+39 02 9260 8484

+353 1890 924 204

0120 421 345

Ireland

Japan

Korea

080 769 0800

Mexico

Netherlands

Norway

Russia

(5) 258-4826

+31 (0) 20 547 2111

+47 67101 080

+7 (095) 797 3930

+34 91 631 3300

0200 88 22 55

Spain

Sweden

Switzerland

United Kingdom

United States

0800 80 5353

+44 (0) 7004 666666

+1 (877) 447 7278

7-19

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Index

ASNR, 48

softkey, 28

AVERAGE annotation, 7

average wavelength, iii, 7

Avg WL key, 7, 8

Numerics

1 nm annotation, 27, 30

BAR OFF softkey, 11

BAR ON softkey, 11

bit error rate, 25

block diagram, 5

BROAD annotation, 9

BROAD softkey, 9

broadband devices, measuring, 9

programming command, 84

broadband mode, 9, 5, 8

BY PWR annotation, 6

BY WL annotation, 6

ABORt programming command, 104

ABORT softkey, 39

ac power cables, 6

adapters, fiber optic, 17

adding parameters, 25

address. See GPIB address

Agilent Technologies offices, 18

air, measurements in, 37

AM modulation, 15, 34

amplitude

offset, 36

specifications, 6, 9

annotation

* (asterisk), 4, 14

1 nm, 27, 30

cabinet, cleaning, vii, 2

CAL softkey, 8

AVERAGE, 7

BROAD, 9

BY PWR, 6

BY WL, 6

CALCulate1 subsystem, 25

CALCulate2 subsystem, 31

CALCulate3 subsystem, 14, 34, 37, 39, 44

calibration

DRIFT, 22

accuracy, 3

M, 4

cycle, 2

PEAK, 4

elevation, 8

PWR OFS, 36

Remote, 3

S/N AUTO, 25

measurements, 37

medium for light, 9

care

S/N USER, 25

STD AIR, 37

VAC, 37

Appl’s

key, 23, 28, 31

menu map, 5

ARRay programming command, 15

of cabinet, vii, 2

of fiber optics, v

case sensitivity, 24

channel spacing, 19

characteristics, 5

chirped lasers, 9

classification

ASNR

product, vii

CLEar programming command, 46

COUNt programming command, 47

* (asterisk), 4, 14

attenuation. See external attenuation

audio modulation, effects of, 15, 34

AUTO

classification, laser, vi, 12

cleaning

adapters, 49

cabinet, vii, 2

fiber-optic connections, 40, 48

non-lensed connectors, 48

CLEAR softkey, 23

programming command, 69

Index-1

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Index

*CLS, 21, 3

CM –1 softkey, 13

DEVICES softkey, 9

DFB lasers, 9

Cmd_opc subroutine, 29

dispersion. See calibration, measurements

colon, 25

display

commands

combining, 24

annotation. See annotation

cursor, 6

common, 23

modes, 3

measurement instructions, 23

non sequential, 12, 29, 34, 35, 37, 38, 39, 40, 41,

42, 43, 85, 105, 106

standard SCPI, 23

resolution, 4, 6, 9

scrolling through, 6

setting update rate, 14

softkeys blanked, 3

update rate, 13

termination, 27

common commands

*CLS (clear status), 3

*ESE (event status enable), 28, 3

*ESR (event status register), 5

*IDN (identification number), 29, 6

*OPC (operation complete), 29, 7

*RST (reset), 29, 8

DISPlay subsystem, 75

down-arrow softkey, 6

DRANge programming command, 34

DRIFT

annotation, 22

softkey, 23

drift, laser. See laser drift

*SRE (service request enable), 10

*STB (status byte), 12

*TRG (trigger), 13

dust caps, 48

dust covers, 17

*TST (test), 13

*WAI (wait), 14

definition, 23

E15 MAX NUMBER OF SIGNALS FOUND message,

sending, 25

E46 NUM LINES < NUM REFS message, 23

E47 NUM LINES > NUM REFS message, 23

EDFA amplifier, 9

ELEV softkey, 8, 38

elevation

computer control, 5

CONFigure measurement instruction, 15

connector

care, 40

connector care, 40

changing feet to meters, 8, 38

effects of, 37

entering, 8, 38

ELEVation programming command, 84, 85

ENABle programming command, 92

EOI signal, 27

Cont key, 14, 23

CONT softkey, 39

CONTinuous programming command, 105

cotton swabs, 48

covers, dust, 17

cursor, 6

Err_mngmt subroutine, 29

error

messages, 11

damaged shipment, 4

data corrupt or stale, 26, 8, 15

data questionable, 15

DATA? programming command, 26, 32, 49, 88

DBM softkey, 13

queue, 22

ERRor programming command, 98

Error_msg subroutine, 28

*ESE, 28, 3

*ESR, 5

default GPIB address, 3

Delta Off softkey. See Off

Delta On softkey. See On

EVENT programming command, 91, 93

event status enable register, 28, 4

example programs, 28

Index-2

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Index

increase source accuracy, 41

measure DFB laser, 30

HP BASIC, 2, 28

measure SNR, 39

measure WDM channel drift, 34

measure WDM channel separation, 37

measure WDM channels, 32

external attenuation, 36

*IDN?, 29, 6

IEC Publication 1010, vi

IEEE 488.2 standard, 2

IMMediate programming command, 80, 106

init ignored, 15

initializing the instrument, 3

input

connector, iii, 40

power, definition of, 4

INPUT connector, v

inspecting

Fabry-Perot lasers, iii, 9

measuring, 15, 31

fast fourier transform, 29

FAST softkey, 14, 9, 88

FETCh measurement instruction, 15

fiber optics

instrument, 4

adapters, 17

installing, 2

care of, v

instrument

cleaning connections, 40

connectors, covering, 12

firmware version

displayed, 7

addressing over GPIB, 3

default state, 2

front view, 15

preset conditions, 100, 2

rear view, 15

over GPIB, 6

flatness, 3, 6, 9

returning for service, 11

state when turned on, 100, 2

integration limits, 9

FNIdentity function, 29

FP TEST softkey, 31

FPERot programming command, 62–67

FREQuency programming command, 19, 51, 70

front panel

laser

adapters, 17

labels, 15

aperture, vi

classification, vi, 12

drift, iii, 22, 23

line separation, iii, 18

linewidth, 2

lockout, 3

fuse

values, vii

modulated, 34

tuning power, 4

Laser safety, 12

LEFT programming command, 76

LIM OFF softkey, 10

LIM ON softkey, 10

LINE key, 7

GPIB

address, 3

address, changing from front panel, 4

address, default, 3

softkey, 4

linearity, 4, 6, 9

line-power

cable, 5

cables, 18

initial state, 100, 2

requirements, 5

hardcopy. See printer

HCOPy subsystem, 80

HELP:HEADers? programming command, 99

Index-3

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Index

specifications, 11

linewidth, 2

List by Power

menu map, 6

mode, 9

softkey, 6, 23

List by WL

relative power, 18

relative wavelength, 18

repetitive data formats, 27

signal-to-noise, 25, 28

single acquisition, 14

SONET format present, 27, 35

speed, 13, 9, 29, 88

total power, 8

key, 6

menu map, 7

units, 12

mode, 9

update rate, 9, 29, 88

in vacuum, 37

measuring

chirped lasers, 9

EDFA amplifiers, 9

menu maps, 4

softkey, 6, 23

LOCAL softkey, 3

long form commands, 23

lowercase letters, 24

messages, error, 11

microwatts, 13

milliwatts, 13

M annotation, 4

MAGNitude programming command, 87

MAX NUMBER OF SIGNALS FOUND, 17

maximum power input, iv

MAXimum programming command, 76

MAX-MIN softkey, 23

MEASure measurement instruction, 30, 32, 15

measurement

modulated lasers, 34

monitoring the instrument, 16

MW softkey, 13

nanometers, 13

accuracy, 3

NARROW softkey, 9

air, in, 37

narrowband mode, 9

AM modulation, 15, 34

audio modulation, effects of, 15, 34

average wavelength, 7

calibration, 37

new-line character, 27

NEXT PK softkey, 5

NEXT programming command, 77

NEXT WL softkey, 5

channel separation, 20

channel spacing, 19

NM softkey, 13

noise declaration, 13

continuous acquisition, 14

cycle time, 4, 7, 10

noise power

automatic interpolation, 26

definition of peaks, 15

elevation, effects of, 37

Fabry-Perot lasers, 31

flatness, 21

via GPIB, 5

instructions, 23, 15

bandwidth, 27, 30

user entered wavelength, 27

non-sequential command, 12, 29, 34, 35, 37, 38,

39, 40, 41, 42, 43, 85, 105, 106

NORMAL softkey, 14, 9, 88

notation definitions, 2

NTRansition programming command, 94

NUM LINES < NUM REFS, 23

NUM LINES > NUM REFS, 23

numbers, 25

laser drift, 22

laser line separation, 18

modulated lasers, effects of, 34

monitoring performance over time, 22

multiple laser lines, 6, 12

of broadband devices, 9

PRBS format present, 27, 35

Index-4

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Index

PRBS, 27, 35

Preset

conditions set by, 100, 2

key, 2, 9, 4

menu map, 8

PRESet programming command, 50, 59, 96, 100

PREV PK softkey, 5

PREV WL softkey, 5

PREVious programming command, 77

Off

key, 20

menu map, 8

key, 20

menu map, 7

*OPC, 29, 3, 7

OPTICAL INPUT connector, iii, vi, 14

output queue, 22, 27

key, 39

menu map, 9

printer

cable, 6

connecting, 6

output, 39

packaging for shipment, 13

PARALLEL PRINTER PORT connector, 6, 39

parameters, adding, 25

PEAK

programming, 2

command notation convention, 2

examples. See example programs

list of commands by key, 48

list of commands by subsystem, 43

measurement instructions, 15

programming command, 48

PTRansition programming command, 95

PWR BAR softkey, 11

PWR OFS

annotation, 4

softkey, 5, 28

peak

definition of, 15

excursion, 9, 16

power, iii, 4

threshold limit, 15, 17, 35

wavelength, iii, 4

Peak WL

key, 4

menu map, 8

softkey, 4, 23

annotation, 36

softkey, 36

∆ PWR softkey, 21

performance tests, 2

PEXCursion programming command, 33

PK EXC softkey, 17

PK THLD softkey, 17

POINts? programming command, 29, 34, 68

polarization dependence, 4, 6, 9

power

queries, 27

multiple, 27

queues, 22

bar, iv, 4, 11

maximum before damage, 2

maximum input, iv

maximum measurable, 2

measuring total, 7, 32, 35

peak, 4

separation, 18

state when turned on, 100, 2

tuning laser, 4

POWer programming command, 17, 51, 107

POWER softkey, 13

radiation exposure, vi

range, wavelength, 37

READ measurement instruction, 15

rear panel

labels, 15

regulatory duration, 2

Remote annotation, 3

repetitive data formats, 27

RESet programming command, 59

RESET softkey, 21, 23, 24

Index-5

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Index

return loss, 4, 7, 10

returning

Single key, 14, 16, 31

softkey

data, 27

menus, 4

for service, 11

SONET, 27, 35

RF modulation, 35

RIGHT programming command, 78

*RST, 3, 29, 8

specifications, 2, 5

and wideband mode, 9

definition of terms, 2

operating, 11

spurious signals

suppressing, 15

*SRE, 10

standard

air, 9, 37

event status register, 5

SCPI commands, 23

STATe programming command, 35, 50, 54, 55, 56,

57, 58, 60, 61, 73, 78

status

byte register, 12

reporting, 16

STATus subsystem, 90

*STB, 12

STD AIR

annotation, 37

softkey, 9, 38

S/N AUTO annotation, 25

S/N softkey, 28

S/N USER annotation, 25

safety, vi, vii

laser classification, vii

symbols, iii

sales and service offices, 18

SCALar programming command, 15

SCPI (standard commands for programmable in-

struments)

standard, 2

syntax rules, 23

SELECT softkey, 6, 19

selectivity, 4, 6, 9

semicolon, 23

sending common commands, 25

SENSe subsystem, 83

sensitivity, 4, 6, 9

serial number

instrument, 4

subsystems, 23

swabs, 48

syntax rules, 23–27

SYSTem subsystem, 97

service, 11

request enable register, 21, 10

returning for, 11

Tempo subroutine, 29

terahertz, 13

sales and service offices, 18

Set_ese subroutine, 28

settings conflict error, 14, 36, 48, 50, 54, 55, 57,

58, 60, 61, 73, 15

Setup

key, 10, 11, 4

THRSHLD softkey, 16

THZ softkey, 13

total power, iii, 8

maximum measurable, 36

measuring, 7

menu map, 10

shipping

transient data, 11

*TRG, 13

procedure, 12

short form commands, 23

signal-to-noise

trigger ignore, 15

TRIGger subsystem, 103

*TST, 13

measurements, 25

noise calculation, 25, 69

ratios, iii

UNIT subsystem, 107

specification, 7, 10

Index-6

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Index

units of measure, 12

UNITS softkey, 12

up-arrow softkey, 6

UPDATE softkey, 14

uppercase letters, 24

USER softkey, 28

USER WL softkey, 28

UW softkey, 13

VAC annotation, 37

VACuum programming command, 86

VACUUM softkey, 9, 38

vacuum, measurements in, 37

VERSion programming command, 102

*WAI, 14

wave number, 13

wavelength

definition of, 3

input range, 2

peak, 4

range, 37

separation, 18

specifications, 5, 8

WAVelength programming command, 21, 52, 71

WDM

flatness, 21

system, 18

white space characters, 25

WL LIM softkey, 10

WL REF softkey, 28

∆ WL softkey, 20

WL softkey, 13

∆ WL/PWR softkey, 20

WLIMit programming command, 37, 38, 40, 41, 42,

WNUMber programming command, 23, 53, 72

Index-7

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www.agilent.com

 Agilent Technologies GmbH 2004

Printed in Germany August 2004

Second edition, August 2004

86120-90C03

Agilent Technologies

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