Agilent 8168F Users Guide

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User's Guide

HP 8167A/8D/8E/8F

Tunable Laser Source

SERIAL NUMBERS

This guide applies to the 8167A, 8168D, 8168E and 8168F tunable laser sources.

ABCDE

HP Part No. 08168-91021

Printed in Germany

Second Edition

E0197

Notices

This document contains proprietary

information that is protected by

No part of this document may be

photocopied, reproduced, or

translated to another language

without the prior written consent of

Hewlett-Packard GmbH.



Hewlett-Packard GmbH

Herrenberger Str. 130

71034 Boeblingen

Germany

Subject Matter

The information in this document is

subject to change without notice.

Hewlett-Packard makes no warranty

of any kind with regard to this

printed material, including, but not

limited to, the implied warranties of

merchantability and tness for a

particular purpose.

Hewlett-Packard shall not be liable

for errors contained herein or for

incidental or consequential damages

in connection with the furnishing,

performance, or use of this material.

Printing History

New editions are complete revisions

of the guide reecting alterations in

the functionality of the instrument.

Updates are occasionally made to

the guide between editions. The

date on the title page changes when

an updated guide is published. To

nd out the current revision of the

guide, or to purchase an updated

guide, contact your Hewlett-Packard

representative.

Warranty

This Hewlett-Packard instrument

product is warranted against defects

in material and workmanship for a

period of one year (8167A and

8168D) or three years (8168E and

8168F) from date of shipment.

During the warranty period, HP will,

at its option, either repair or replace

products that prove to be defective.

For warranty service or repair, this

product must be returned to a service

facility designated by HP. Buyer shall

prepay shipping charges to HP and

HP shall pay shipping charges to

return the product to Buyer.

However, Buyer shall pay all shipping

charges, duties, and taxes for

products returned to HP from

another country.

HP warrants that its software and

rmware designated by HP for use

with an instrument will execute its

programming instructions when

properly installed on that instrument.

HP does not warrant that the

operation of the instrument,

software, or rmware will be

uninterrupted or error free.

Limitation of Warranty

The foregoing warranty shall not

apply to defects resulting from

improper or inadequate maintenance

by Buyer, Buyer-supplied software or

interfacing, unauthorized

modication or misuse, operation

outside of the environmental

specications for the product, or

improper site preparation or

maintenance.

No other warranty is expressed or

Exclusive Remedies

The remedies provided herein are

Buyer's sole and exclusive remedies.

Hewlett-Packard shall not be liable

for any direct, indirect, special,

incidental, or consequential

damages whether based on contract,

tort, or any other legal theory.

Assistance

Product maintenance agreements

and other customer assistance

agreements are available for

Hewlett-Packard products.For any

assistance contact your nearest

Hewlett-Packard Sales and Service

Oce.

Certication

Hewlett-Packard Company certies

that this product met its published

specications at the time of

shipment from the factory.

Hewlett-Packard further certies

that its calibration measurements

are traceable to the United States

National Institute of Standards and

Technology, NIST (formerly the

United States National Bureau of

Standards, NBS) to the extent

allowed by the Institutes's

calibration facility, and to the

calibration facilities of other

International Standards Organization

members.

ISO 9001 Certication

Produced to ISO 9001 international

quality system standard as part of

our objective of continually

increasing customer satisfaction

through improved process control.

implied. Hewlett-Packard specically

disclaims the implied warranties of

Merchantability and Fitness for a

Particular Purpose.

First Edition : 1st April 1996 : 08168-91021 : E0496 : 1st June 1996 : 08168-91021 : E0696

Second Edition : 1st January 1997 : 08168-91021 : E0197

Safety Summary

The following general safety precautions must be observed during all phases

of operation, service, and repair of this instrument. Failure to comply with

these precautions or with specic warnings elsewhere in this manual violates

safety standards of design, manufacture

, and intended use of the instrument.

Hewlett-Packard Company assumes no liability for the customer's failure to

comply with these requirements.

General

This is a Safety Class 1 instrument (provided with terminal for

protective earthing) and has been manufactured and tested according to

international safety standards.

Operation - Before applying power

Comply with the installation section.

Additionally, the following shall be observed:

Do not remove instrument covers when operating.

Before the instrument is switched on, all protective earth terminals

, extension

cords, auto-transformers and devices connected to it should be connected to a

protective earth via a ground socket. Any interruption of the protective earth

grounding will cause a potential shock hazard that could result in serious

personal injury.

Whenever it is likely that the protection has been impaired, the instrument

must be made inoperative and be secured against any unintended operation.

Make sure that only fuses with the required rated current and of the specied

type (normal blow, time delay, etc.) are used for replacement. The use of

repaired fuses and the short-circuiting of fuseholders must be avoided.

Adjustments described in the manual are performed with power supplied to

the instrument while protective covers are removed. Be aware that energy at

many points may, if contacted, result in personal injury.

Any adjustments, maintenance, and repair of the opened instrument under

voltage should be avoided as much as possible, and when unavoidable, should

be carried out only by a skilled person who is aware of the hazard involved.

Do not attempt internal service or adjustment unless another person, capable

of rendering rst aid and resuscitation is present. Do not replace components

with power cable connected.

Do not operate the instrument in the presence of ammable gases or fumes.

Operation of any electrical instrument in such an enviroment constitutes a

denite safety hazard.

Do not install substitute parts or perform any unauthorized modication to

the instrument.

Be aware that capacitors inside the instrument may still be charged even if

the instrument has been disconnected from its source of supply.

Safety Symbols

The apparatus will be marked with this symbol when it is

necessary for the user to refer to the instruction manual in

order to protect the apparatus against damage.

Caution, risk of electric shock.

Frame or chassis terminal.

Protective conductor terminal.

Hazardous laser radiation.

Warning

Caution

The WARNING sign denotes a hazard. It calls attention to

a procedure, practice or the like, which, if not correctly

performed or adhered to, could result in injury or loss of

life. Do not proceed beyond a WARNING sign until the

indicated conditions are fully understood and met.

The CAUTION sign denotes a hazard. It calls attention to

an operating procedure, practice or the like, which, if not

correctly performed or adhered to, could result in damage to

or destruction of part or all of the equipment. Do not proceed

beyond a CAUTION sign until the indicated conditions are fully

understood and met.

Initial Safety Information for the Tunable Laser

Source

The Specications for these instruments are as follows:

Laser Type

Laser Class

According to 21 1 1 1 IIIb

CFR 1040.10 (USA)

According to 3A 3A 3A 3A

IEC 825-1 (Non-USA)

EN 60825-1 Europe

Permissible Output Power (CW)

Beam Diameter

Numerical Aperture

Wavelength

HP 8167A HP 8168D HP 8168E HP 8168F

Fabry Fabry Fabry Fabry

Perot-Laser Perot-Laser Perot-Laser Perot-Laser

InGaAsP InGaAsP InGaAsP InGaAsP

1.6mW

9.9mW

9m 9m 9m 9m

0.1 0.1 0.1 0.1

1280-1330nm 1490-1565nm 1475-1575nm 1450-1590nm

Note

USA

The laser safety warning labels are xed on the instrument

(except the 8168F, see label below).

vii

Class IIIb stickers, required for 8168F in USA only

Caution

Note

You

MUST

Center for repair and calibration.

viii

The use of optical instruments with this product will increase

eye hazard.

Non-USA

A sheet of laser safety warning labels are included with the

instrument. You

onto the outside of the instrument, in a position where they are

clearly visible to anyone using the instrument.

return instruments with malfunctioning laser boxes to an HP Service

MUST

stick the labels in the local language

The instrument has built in safety circuitry that will disable the optical output

in the case of a fault condition.

Warning

Use of controls or adjustments or performance of

procedures other than those specied for the laser source

may result in hazardous radiation exposure.

Refer Servicing only to qualied and authorized personnel.

Do not enable the laser when there is no ber attached to

the optical output connector.

The optical output connector is at the bottom right of the

instrument front panel.

The laser is enabled by pressing the gray button beside

the optical output connector on the front panel. The laser

is enabled when the green LED on the front panel of the

instrument is lit.

Under no circumstances look into the end of an optical

cable attached to the optical output when the device is

operational.

The laser radiation is not visible to the human eye, but it

can seriously damage your eyesight.

Sicherheitsinformation fur Laser Quellen

Die Spezikationen f ur die Ger ate sind wie folgt:

HP 8167A HP 8168D HP 8168E HP8168F

Laser Typ

Fabry Fabry Fabry Fabry

Perot-Laser Perot-Laser Perot-Laser Perot-Laser

InGaAsP InGaAsP InGaAsP InGaAsP

Laser Klasse

Gem a IEC 825-1 3A 3A 3A 3A

(EN60825-1 Europa)

Zulassige Ausgangsleistung

Strahldurchmesser

Numerische Apertur



Wellenl

ange

1.6mW

9m 9m 9m 9m

0.1 0.1 0.1 0.1

1280-1330nm 1490-1565nm 1470-1575nm 1450-1590nm

Hinweis

1.6mW

9.9mW

Ein Blatt mit Laser Warnaufklebern ist jedem Ger at beigef ugt.

Die Aufkleber m ussen in der Landessprache,fur den Anwender

gut sichtbar, an der Auenseite des Ger ates angebracht werden.

Ger ate mit defekten Laser m ussen zur Reparatur oder zur Kalibration an ein HP

Service B uro geschickt werden.

Das Ger at hat eine eingebaute Sicherheitsschaltung, die den Laserausgang im

Falle einer St orung abschaltet.

Warnung

Bedienung, Abgleicharbeiten oder die Durchfuhrung von

Tests, die nicht im Handbuch angegeben sind, konnen zum

Austritt gefahrlicher Strahlung fuhren.

Warnung

Reparaturarbeiten durfen nur von qualiziertem und

bevollmachtigtem Personal durchgefuhrt werden.

Warnung

Laser nicht ohne angeschlossenes Glasfaserkabel

einschalten.

Der optische Ausgang bendet sich am unteren rechten

Teil der Frontplatte. Mit dem danebenliegenden grauen

Druckschalter wird der Laser ein- bzw. ausgeschaltet. Bei

eingeschaltetem Laser leuchtet eine grune LED an der

Frontplatte des Einschubes.

Wenn der Laser eingeschaltet ist, darf unter keinen

Umstanden in das Ende des optischen Kabels oder in den

Laserausgang am Gerat geschaut werden.

Der Laserstrahl ist fur das menschliche Auge unsichtbar,

kann aber das Sehvermogen ernsthaft verletzen.

Informations et Consignes de Securite Relativesa

l'Utilisation des Lasers.

Les Sp ecications de l'appareil sont les Suivantes:

HP 8167A HP 8168D HP 8168E HP8168F

Type du Laser

Fabry Fabry Fabry Fabry

Perot-Laser Perot-Laser Perot-Laser Perot-Laser

InGaAsP InGaAsP InGaAsP InGaAsP

Classe du Laser

Conforme au IEC 825-1 3A 3A 3A 3A

(EN 60825-1 Europe)

Permit Puissance de Sortie

Diametre du Faisceau

Ouverture Numerique

Longueur d'Onde

1.6mW

9m 9m 9m 9m

0.1 0.1 0.1 0.1

1280-1330nm 1490-1565nm 1475-1575nm 1450-1590nm

Remarque

9.9mW

Les etiquettes de s ecurit e sont incluses dans l'appareil. Il est

obligatoire de coller une etiquette en langage local al'exterieur

de l'appareil de telle sorte qu'elle soit parfaitement visible par

l'utilisateur.

Il est recommand e de xer l' etiquette de s ecurit e sur la partie inf erieure gauche

de la face avant de l'appereil.

En cas de mauvais fonctionnement du laser, celui doit ^etre renvoy e

imperativement accompagn e de l'appareil dans un centre de maintenance

Hewlett-Packard ou agr ee Hewlett-Packard pour r eparation et calibration.

L'appareil comporte un syst eme de s ecurit e mettant hors service la sortie

optique en cas de mauvais fonctionnement du laser.

xii

Attention

L'utilisation du laser en dehors de ses limites de

performances et des procedures denies par HP peut

conduirea une exposition aux radiations dangereuse pour

l'utilisateur.

Attention

Seul le personnel autorise par HP est qualie pour

intervenir sur le laser.

Ne pas mettre le laser sous tension sans s'^etre assure

qu'une bre optique est bien xee sur le connecteur.

Le connecteur de sortie optique est situe au bas de la face

avant de l'appareil.

La mise en service du laser s'eectue par la pression du

bouton gris situea cote de la sortie optique au bas de la

face avant de l'appareil. L'illumination de la LED verte

indique que le laser est en activite.

Ne tentez en aucun cas de regarder l'extremite de la bre

optique attachee au connecteur lorsque le laser est en

activite.

Bien que la lumiereemise par le laser ne soit pas visible elle

peut cependant^etre dangereuse pour la vue.

xiii

Introduction

This guide is arranged into four categories:

Getting Started

This section gives an introduction to the instrument, and aims to make the

instrument familiar to you: Chapter 1.

Local Control

This is the information on how to control the instrument from the front panel:

Chapters 2 and 3.

Remote Control

This is the information on how to control the instrument over the HP-IB

is made of general information for using the HP-IB

some programming examples.: Chapters 4, 5, and 6.

Additional Information

This is supporting information of a non-operational nature. This contains

installation information, accessories, specications, function tests, cleaning

procedures, and error codes: Appendices A through G.

, a command reference, and

. This

Attenuator

xiv

Some information in this manual applies only to the tunable

laser source with the built in optical attenuator (option 003).

This paragraph is marked the way that all the passages which

only apply to the attenuator option are marked in this manual.

Contents

1. Getting Started

What is a Tunable Laser Source? ................ 1-1

A description of the Front Panel .. ...... ...... .. 1-2

Starting the 8168F . . . . . . . . . . . . . . . . . . . . . . . 1-3

Getting Help . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

Changing the Value of a Parameter ............... 1-5

Making Big Changes to a Parameter . . . . . . . . . . . . . . 1-6

Making a Small Change to a Parameter ............ 1-6

Setting a Parameter to its Default Value . . . . . . . . . . . . 1-7

If You Make a Mistake .. ...... ...... ..... . 1-7

If the Parameter Will Not Change . . . . . . . . . . . . . . . 1-8

A Sample Session ...... ...... ...... ..... 1-8

Measuring the Power of a Modulated Signal . . . . . . . . . . 1-8

Setting the Wavelength . . . . . . . . . . . . . . . . . . . 1-9

Setting the Modulated Power . . . . . . . . . . . . . . . . 1-9

Measuring a Wavelength Characteristic ............ 1-11

Setting Up the Wavelength Sweep ............. 1-11

Performing the Wavelength Characteristic Measurement ... 1-12

2. Setting Wavelength and Power

Setting the Wavelength . . . . . . . . . . . . . . . . . . . . . 2-2

Setting the Wavelength Directly ...... ...... ... 2-2

Setting a Relative Wavelength ...... ...... .... 2-3

Changing the Base Wavelength . . . . . . . . . . . . . . . 2-3

Performing a Wavelength Sweep ................ 2-4

Setting the Wavelength Sweep ................ 2-5

Setting the Maximum Power for the Sweep Range . . . . . . . 2-5

Executing an Automatic Sweep . . . . . . . . . . . . . . . . 2-6

Performing a Manual Sweep ........ ...... ... 2-6

Setting the Power ....................... 2-8

Setting the Output Power of a CW Signal ........... 2-8

Setting Power and Attenuation . . . . . . . . . . . . . . . 2-9

Contents-1

What is Excessive Power? .................. 2-9

The Analog Output ..................... 2-9

Setting a Modulated Signal . . . . . . . . . . . . . . . . . . . 2-10

Using the Internal Modulation ................ 2-11

Setting the Output Power of a Modulated Signal . . . . . . . 2-11

Setting the Frequency of a Modulated Signal ........ 2-11

The Modulation Output .................. 2-12

Using External Modulation . . . . . . . . . . . . . . . . . . 2-12

Setting the Output Power of a Modulated Signal . . . . . . . 2-13

The Modulation Input .. ...... ...... ..... 2-13

Using Coherence Control . . . . . . . . . . . . . . . . . . . . 2-13

Setting the Output Power of a Coherence Control Signal .... 2-13

The Coherence Control Uncal Power ............. 2-14

3. Other Functions

Storing and Recalling Instrument Settings . . . . . . . . . . . . 3-1

Using the System Utilities ................... 3-2

Switching the Instrument into Stand-By . . . . . . . . . . . . 3-3

Increasing the Lifetime of the Display . . . . . . . . . . . . 3-3

Setting the HP-IB Address .................. 3-4

Setting the Modulation Output .... ...... ...... 3-4

Getting Information about the Instrument . . . . . . . . . . . 3-4

Setting the Date and Time ...... ...... ...... 3-4

Performing a Selftest . . . . . . . . . . . . . . . . . . . . .

Auxiliary Functions ........ ...... ...... .. 3-6

Viewing the Power as a Function of Wavelength . . . . . . . . 3-6

Setting the Peak Power ................... 3-7

Passive Component Test (PACT).. ...... ...... .. 3-7

Automatic Realignment ................... 3-7

Secure .......... ...... ...... ..... 3-9

Lock the Instrument . . . . . . . . . . . . . . . . . . . . 3-9

Change the Password .. ...... ..... ...... 3-11

3-5

4. Programming the Tunable Laser Source

HP-IB Interface ........................ 4-1

Setting the HP-IB Address .. ...... ...... ..... 4-3

Returning the Instrument to Local Control ........... 4-3

How the Tunable Laser Source Receives and Transmits Messages . 4-3

How the Input Queue Works ................. 4-3

Clearing the Input Queue . . . . . . . . . . . . . . . . . . 4-4

The Output Queue . . . . . . . . . . . . . . . . . . . . . . 4-4

Contents-2

The Error Queue . . . . . . . . . . . . . . . . . . . . . . . 4-4

Some Notes about Programming and Syntax Diagram Conventions 4-5

Short Form and Long Form.................. 4-5

Command and Query Syntax ................. 4-5

5. Remote Commands

Units ............................. 5-1

Command Summary ...................... 5-2

The Common Commands . . . . . . . . . . . . . . . . . . . . 5-5

Common Status Information ................. 5-5

SRQ, The Service Request ................. 5-6

*CLS ............................ 5-7

*ESE ............................ 5-7

*ESE? . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8

*ESR? . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8

*IDN? . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9

*OPC . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-10

*OPC? ........ ...... ...... ...... 5-10

*OPT? ...... ...... ...... ...... ... 5-10

*RCL ............................ 5-11

*RST ............................ 5-11

*SAV ............................ 5-12

*SRE ............................

*SRE? . . . . . . . . . . . . . . . . . . . . . . . . . . .

*STB? . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-13

*TST? . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-14

*WAI ............................ 5-16

:DISPlay Commands ...................... 5-16

:DISPlay:ENABle ...................... 5-16

:DISPlay:ENABle? . . . . . . . . . . . . . . . . . . . . . 5-16

:LOCK Commands ...... ...... ...... ..... 5-17

:LOCK ........................... 5-17

:LOCK? . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-17

:OUTPut Commands ...... ...... ...... .... 5-17

:OUTPut[:STATe].... ...... ...... ...... . 5-17

:OUTPut[:STATe]? ........ ...... ...... . 5-18

[:SOURce] Commands ..................... 5-18

[:SOURce]:AM:INTernal:FREQuency . . . . . . . . . . . . . . 5-18

[:SOURce]:AM:INTernal:FREQuency? ...... ...... 5-19

[:SOURce]:AM:SOURce . . . . . . . . . . . . . . . . . . . . 5-19

[:SOURce]:AM:SOURce? .................. 5-19

5-12

5-13

Contents-3

[:SOURce]:AM:STATe......... ...... ...... 5-20

[:SOURce]:AM:STATe? ................... 5-20

[:SOURCE]:MODOUT . . . . . . . . . . . . . . . . . . . . . 5-21

[:SOURCE]:MODOUT? ........ ...... ..... 5-21

[:SOURce]:POWer:ATTenuation .... ...... ...... 5-22

[:SOURce]:POWer:ATTenuation? . . . . . . . . . . . . . . . 5-22

[:SOURce]:POWer:ATTenuation:AUTO............. 5-23

[:SOURce]:POWer:ATTenuation:AUTO? ........... 5-23

[:SOURce]:POWer:ATTenuation:DARK............. 5-24

[:SOURce]:POWer:ATTenuation:DARK? ........... 5-24

[:SOURce]:POWer[:LEVel][:IMMediate][:AMPlitude] . . . . . . . 5-25

[:SOURce]:POWer[:LEVel][:IMMediate][:AMPlitude]? ..... 5-25

[:SOURce]:POWer:UNIT ................... 5-26

[:SOURce]:POWer:UNIT? .. ...... ...... .... 5-26

[:SOURce]:WAVElength[:CWj:FIXED] ...... ...... . 5-27

[:SOURce]:WAVElength[:CWj:FIXED]? . . . . . . . . . . . . 5-27

[:SOURce]:WAVElength:REFerence? . . . . . . . . . . . . . . 5-28

[:SOURce]:WAVElength:REFerence:DISPlay .......... 5-28

[:SOURce]:WAVElength:FREQuency . . . . . . . . . . . . . . 5-28

[:SOURce]:WAVElength:FREQuency? ............ 5-28

:STATus Commands ...................... 5-29

:STATus:OPERation:CONDition? ............... 5-30

:STATus:OPERation:ENABle .................

:STATus:OPERation:ENABle? . . . . . . . . . . . . . . . .

5-31

:STATus:OPERation[:EVENt]? . . . . . . . . . . . . . . . . . 5-31

:STATus:OPERation:NTRansition ........ ...... . 5-32

:STATus:OPERation:NTRansition? . . . . . . . . . . . . . . 5-32

:STATus:OPERation:PTRansition ............... 5-32

:STATus:OPERation:PTRansition? . . . . . . . . . . . . . . 5-32

:STATus:QUEStionable:CONDition? .............. 5-33

:STATus:QUEStionable:ENABle . . . . . . . . . . . . . . . . 5-33

:STATus:QUEStionable:ENABle? .............. 5-33

:STATus:QUEStionable[:EVENt]? ............... 5-34

:STATus:QUEStionable:NTRansition . . . . . . . . . . . . . . 5-34

:STATus:QUEStionable:NTRansition? .......... .. 5-34

:STATus:QUEStionable:PTRansition . . . . . . . . . . . . . . 5-35

:STATus:QUEStionable:PTRansition? ............ 5-35

:STATus:PRESet ...... ...... ...... ..... 5-35

:SYSTem Commands ...................... 5-36

:SYSTem:DATe........................ 5-36

:SYSTem:DATe? .. ...... ...... ...... .. 5-36

Contents-4

:SYSTem:ERRor? . . . . . . . . . . . . . . . . . . . . . . . 5-36

:SYSTem:TIMe . . . . . . . . . . . . . . . . . . . . . . . . 5-37

:SYSTem:TIMe? ...................... 5-37

:TRACe Commands . . . . . . . . . . . . . . . . . . . . . . . 5-37

:TRACe:CATalog? ........ ...... ...... .. 5-37

:TRACe:POINts?<trace name>............... 5-38

:TRACe[:DATa]?<trace name>...... ...... .... 5-38

Other Commands ....................... 5-38

WAVEACT.......................... 5-38

6. Programming Examples

Example 1 - Checking Communication ............. 6-2

Example 2 - Status Registers and Queues ............ 6-3

Example 3 - Measuring the Power of a Modulated Signal . . . . . 6-7

Example 4 - Measuring a Wavelength Characteristic .. ..... 6-10

Example 5 - Increased Tuning Linearity . . . . . . . . . . . . . 6-12

A. Installation

Safety Considerations ..................... A-1

Initial Inspection . . . . . . . . . . . . . . . . . . . . . . . . A-1

AC Line Power Supply Requirements ........ ...... A-2

Line Power Cable .......... ..... ...... . A-2

Changing the Battery ...... ...... ...... ..

Changing the Fuse . . . . . . . . . . . . . . . . . . . . . .

Operating and Storage Environment .. ...... ...... A-6

Temperature . . . . . . . . . . . . . . . . . . . . . . . . . A-6

Humidity .......................... A-6

Instrument Positioning and Cooling . . . . . . . . . . . . . . A-6

Switching on the Tunable Laser Source ............. A-7

Self test . . . . . . . . . . . . . . . . . . . . . . . . . . . A-7

Initializing . . . . . . . . . . . . . . . . . . . . . . . . . . A-7

Stabilizing . . . . . . . . . . . . . . . . . . . . . . . . . . A-8

Stabilizing during Operation ................ A-8

Signal Outputs. ........................ A-9

Optical Output . . . . . . . . . . . . . . . . . . . . . . . . . A-9

HP-IB Interface ........................ A-10

Connector . . . . . . . . . . . . . . . . . . . . . . . . . . A-10

HP-IB Logic Levels . . . . . . . . . . . . . . . . . . . . . . A-11

Claims and Repackaging .................... A-12

Return Shipments to HP ................... A-12

A-4

Contents-5

B. Accessories

Mainframe .......................... B-1

Options . . . . . . . . . . . . . . . . . . . . . . . . . . . B-2

Option 003: ........................ B-2

Option 007: ........................ B-2

Connector Interfaces and Other Accessories . . . . . . . . . B-2

Option 021, Straight Contact Connector . . . . . . . . . . B-3

Option 022, Angled Contact Connector .......... B-4

Option 023, Diamond HMS-10/HRL Angled, Non-Contact

Connector ...................... B-5

HP-IB Cables and Adapters . . . . . . . . . . . . . . . . . . . B-7

C. Specications

Denition of Terms ...................... C-1

Performance Specications . . . . . . . . . . . . . . . . . . . C-4

Supplementary Performance Characteristics . . . . . . . . . . . C-7

Characteristics . . . . . . . . . . . . . . . . . . . . . . . . C-7

Operating Modes . . . . . . . . . . . . . . . . . . . . . . . C-7

Internal Modulation .................... C-7

External modulation . . . . . . . . . . . . . . . . . . . . C-7

Coherence Control . . . . . . . . . . . . . . . . . . . . . C-7

General . . . . . . . . . . . . . . . . . . . . . . . . . . . C-7

Polarization maintaining ber . . . . . . . . . . . . . . . .

HP-IB Interface ......................

Passive Component Test Software . . . . . . . . . . . . . . C-8

Laser Class ........................ C-8

Environmental ........ ...... ...... .. C-8

Listed options . . . . . . . . . . . . . . . . . . . . . . . C-9

Other Specications ...................... C-9

Declaration of Conformity ................... C-10

C-7

C-8

D. Performance Tests

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . D-1

Equipment Required . . . . . . . . . . . . . . . . . . . . . . D-1

Test Record .......................... D-2

Test Failure .......................... D-3

Instrument Specication .................... D-3

Wavelength Tests ....................... D-3

Relative Wavelength Accuracy ................ D-5

Wavelength Repeatability .. ...... ...... .... D-6

Power Tests . . . . . . . . . . . . . . . . . . . . . . . . . . D-7

Contents-6

Maximum Output Power .... ...... ...... ... D-7

Power Linearity . . . . . . . . . . . . . . . . . . . . . . . D-10

Power Flatness over Wavelength ............... D-14

Power Stability .......... ...... ...... . D-15

Source Spontaneous Emission ................. D-16

E. Cleaning Procedures

The Cleaning Kit . . . . . . . . . . . . . . . . . . . . . . . . E-1

Other Cleaning Tools . . . . . . . . . . . . . . . . . . . . . E-3

Preserving Connectors . . . . . . . . . . . . . . . . . . . . . E-4

Cleaning Instrument Housings ................. E-4

Cleaning Procedures . . . . . . . . . . . . . . . . . . . . . . E-5

Cleaning Cable Connectors . . . . . . . . . . . . . . . . . . E-5

Cleaning Connector Adapters . . . . . . . . . . . . . . . . . E-6

Cleaning Connector Interfaces ................ E-7

Cleaning Bare Fiber Adapters . . . . . . . . . . . . . . . . . E-8

Cleaning Bare Fiber Ends .. ...... ..... ..... E-8

Cleaning Lenses . . . . . . . . . . . . . . . . . . . . . . . E-9

Cleaning Large Area Lenses and Mirrors . . . . . . . . . . . . E-10

Cleaning Fixed Connector Interfaces .......... ... E-11

Cleaning Optical Glass Plates . . . . . . . . . . . . . . . . . E-11

Cleaning Physical Contact Interfaces .... ...... ... E-11

Cleaning Recessed Lens Interfaces .............. E-12

Cleaning Fragile Optical Devices ........ ...... . E-12

Cleaning Metal Filters or Attenuator Gratings ......... E-13

F. Error Messages

Display Messages ........ ...... ...... ... F-1

HP-IB Messages ........................ F-3

Instrument Specic Errors .................. F-3

Command Errors . . . . . . . . . . . . . . . . . . . . . . . F-3

Execution Errors ...................... F-6

Device-Specic Errors .... ...... ...... .... F-7

Query Errors ........................ F-8

Contents-7

G. Backdating

Initial Safety Information for the Tunable Laser Source ..... G-1

Earlier models . . . . . . . . . . . . . . . . . . . . . . . . . G-1

Specications ......................... G-2

Performance Specications . . . . . . . . . . . . . . . . . . G-2

Supplementary Performance Characteristics . . . . . . . . . G-2

Index

Contents-8

Figures

1-1. The Tunable Laser Source Front Panel ...... ...... 1-2

1-2. Starting Screen for the 8168F . . . . . . . . . . . . . . . . . 1-3

1-3. \Secure: Unlock Instrument" Screen ............. 1-4

1-4. \Secure" Screen . . . . . . . . . . . . . . . . . . . . . . . 1-4

1-5. A Summary of the Help Hard- and Softkeys . . . . . . . . . . 1-5

1-6. The Help Topics Menu .................... 1-5

1-7. Connecting the Instruments for the Sample Session .. .... 1-9

1-8. Tunable Laser Source Display after Setting Up W

avelength and

Power . . . . . . . . . . . . . . . . . . . . . . . . . .

1-9. Tunable Laser Source Display during Setting Up for the

Wavelength Sweep .................... 1-11

2-1. A Summary of the additional Output Power Softkeys for the

Attenuator Option .................... 2-2

2-2. Setting the Wavelength Directly .... ...... ..... 2-2

2-3. Setting a Relative Wavelength .......... ...... 2-3

2-4. Setting Up for a Wavelength Sweep . . . . . . . . . . . . . . 2-4

2-5. The Parameters for a Wavelength Sweep .......... . 2-5

2-6. Performing a Manual Sweep ...... ...... ..... 2-7

2-7. Setting the Output Power of a CW Signal ........... 2-8

2-8. The Modulated Signal .................... 2-11

2-9. Setting the Output Power of an Internally Modulated Signal .. 2-11

2-10. External Modulation and Output Power . . . . . . . . . . . . 2-12

2-11. Setting the Output Power of an Externally Modulated Signal . . 2-13

2-12. Setting the Output Power of a Coherence Controlled Signal . . . 2-14

2-13. The Coherence Control Uncalibrated Power and the Maximum

Power Level ....................... 2-14

3-1. User Setting Number 1 . . . . . . . . . . . . . . . . . . . . 3-1

3-2. Summary of the Setting Hard- and Softkeys . . . . . . . . . . 3-2

3-3. The System Screen . . . . . . . . . . . . . . . . . . . . . . 3-3

3-4. Summary of the System Hard- and Softkeys . . . . . . . . . . 3-3

3-5. Auxiliary Functions (8167A, 8168D/E) . . . . . . . . . . . . . 3-6

3-6. Auxiliary Functions (8168F) ................. 3-6

1-10

Contents-9

3-7. Auto Realignment ...................... 3-8

3-8. \Secure" screen . . . . . . . . . . . . . . . . . . . . . . . 3-9

3-9. \Secure: Lock Instrument" screen .............. 3-10

3-10. \Secure" screen - instrument is locked .... ...... .. 3-10

3-11. \Secure: Unlock Instrument" screen ............. 3-10

3-12. \Secure: Change Password" screen . . . . . . . . . . . . . . 3-11

3-13. \Secure: Change Password": Enter new password . . . . . . . 3-11

3-14. \Secure: Change Password": Enter new password again . . . . 3-11

5-1. Common Status Registers . . . . . . . . . . . . . . . . . . . 5-6

5-2. The Status Registers . . . . . . . . . . . . . . . . . . . . . 5-30

6-1. Connecting the Instruments for the Sample Session .... .. 6-8

6-2. Measurement setup for Increased Tuning Linearity ...... 6-12

6-3. Flow chart describing Increased Tuning Linearity program. . . . 6-13

A-1. Line Power Cables - Plug Identication ............ A-2

A-2. Rear Panel Markings . . . . . . . . . . . . . . . . . . . . . A-4

A-3. Releasing the Fuse Holder .......... ...... .. A-5

A-4. The Fuse Holder . . . . . . . . . . . . . . . . . . . . . . . A-5

A-5. Correct Positioning of the Tunable Laser Source . . . . . . . . A-7

A-6. PMF Output . . . . . . . . . . . . . . . . . . . . . . . . . A-10

A-7. HP-IB Connector . . . . . . . . . . . . . . . . . . . . . . . A-11

B-1. Tunable Laser Source Options Overview . . . . . . . . . . . . B-2

B-2. Tunable Laser Source Option 021 Conguration ........ B-3

B-3. Tunable Laser Source Option 022 Conguration ........ B-5

B-4. Tunable Laser Source Option 023 Conguration ........ B-6

C-1. Maximum Specied Output Power for 8168D, E and F (without

options) ......................... C-1

D-1. Test Setup for the Wavelength Tests . . . . . . . . . . . . . . D-4

D-2. Test Setup for the Maximum Output Power Test (except HP

8168F) . . . . . . . . . . . . . . . . . . . . . . . . . . D-8

D-3. Test Setup for the Maximum Output Power Test (HP 8168F only) D-9

D-4. Test Setup for the Power Tests (except Maximum Output Power) D-11

D-5. Test Setup for the Source Spontaneous Emission Test...... D-17

Contents-10

Tables

4-1. HP-IB Capabilities . . . . . . . . . . . . . . . . . . . . . . 4-2

5-1. Units and Allowed Mnemonics ................ 5-1

5-2. Common Command Summary . . . . . . . . . . . . . . . . . 5-2

5-3. Command List . . . . . . . . . . . . . . . . . . . . . . . . 5-3

5-4. Reset State (Default Setting) .... ...... ...... . 5-12

5-5. Specied Wavelength range . . . . . . . . . . . . . . . . . . 5-27

6-1. Program Description: Increased Tuning Linearity ...... . 6-16

A-1. Temperature . . . . . . . . . . . . . . . . . . . . . . . . . A-6

Contents-11

Getting Started

This chapter gives you basic information on how you can operate the tunable

laser source from the front panel.

What is a Tunable Laser Source?

A tunable laser source is a laser source for which the wavelength is not xed.

The Hewlett-Packard tunable laser sources also allow you to set the output

power, and to choose between continuous wave or modulated output power

Note

The single greatest factor aecting the performance of the

tunable laser source, as with all ber optic measurements, is the

cleanliness of the connectors. Ensure that your connectors are

always clean. For cleaning instructions, see Appendix E.

Getting Started 1-1

A description of the Front Panel

Figure 1-1. The Tunable Laser Source Front Panel

A softkey is a key whose function changes depending on the keys that you have

pressed before. The function of a softkey is shown on the display above the

softkey.

The memory card drive allows you to load replacement, or additional, software

to increase the capabilities of your tunable laser source.

There are six function keys. These allow you

to set the wavelength, or to perform a wavelength sweep.

to set the output power,

to save the wavelength and output power setting,

to check or change the system conguration: to test the instrument, to switch

o the laser and display, to change the HP-IB Address, to select whether the

internal modulation signal is available at the Modulation Output constantly,

or only when the power is being output, or to get information about the

instrument and the software revision,

to get help information (see \Getting Help" in the next section of this

chapter), or

to perform an auxiliary application such as examine the power characteristic,

or to set the instrument for maximum power output.

The numeric keypad, the cursor keys, and the modify knob are used to edit

parameters.

1-2 Getting Started

The modulation output gives a TTL level signal of the same frequency as the

internal modulating signal.

The modulation input allows you to input a signal to modulate the power of the

optical output.

The analog output gives a dc-signal proportional to the output power. The

relationship between this voltage level and the output power is not calibrated,

but is approximately 1mV for each 1W.

At the back of the 8168F, you also have a Remote Interlock Connector. This

is to protect the user from injury. If the short-circuit at this BNC connector is

opened, the laser is switched o immediately and cannot be switched on until it

is closed again.

Starting the 8168F

When you turn on the 8168F, the instrument is locked. This is to prevent

unauthorized persons from using this Laser Safety Class IIIb instrument. The

Starting screen for the 8168F is shown below:

Figure 1-2. Starting Screen for the 8168F

If you have not set a new password, you also see the message:

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

default pwd: 8168, please change it!

\Secure" screen until you set a new password (see \Secure" in Chapter 3).

NNNNNNNNNNNNNNNNNNNN

To unlock the instrument, press

Unlock

. This message appears in the

.You see the following screen:

Getting Started 1-3

Figure 1-3. \Secure: Unlock Instrument" Screen

Enter the 4-gure password using the DATA keys. The default password is 8168,

although you can change this from the AUX menu (see \Secure" in Chapter 3).

When you enter the correct password, the instrument is unlocked, and you see

the following screen:

Figure 1-4. \Secure" Screen

NNNNNNNNNNNNNN

Press

Exit

, or any of the function keys, to view the main screen.

Getting Help

Press

When you press this key, the rst help screen is displayed, this is either the last

screen that was used, or the screen with the limit values for the parameters.

1-4 Getting Started

HELP

to get help.

Press

Figure 1-5. A Summary of the Help Hard- and Softkeys

NNNNNNNNNNNNNNNNNNNN

to get the help topics menu.

Figure 1-6. The Help Topics Menu

Choose a topic using

NNNNN

, or the Modify Knob. Press

and

NNNNNNNNNNNNNNNNNNNN

Select

,or

ENTER

to get the information.

NNNNNNNNNNNNNNNNN

Press

Many of the help texts are longer than one screen. You move between screens

of information using

to close the help topics menu without selecting a topic.

NNNNN

and

NNNNN

Changing the Value of a Parameter

What follows is a description of the various methods of changing the value of

parameters on the tunable laser source. Examples in which actual parameter

values are changed are given with the parameter descriptions.

Getting Started 1-5

Making Big Changes to a Parameter

If you are changing the value of a parameter completely, you can directly type

in the value on the keypad, and press

ENTER

Example

To change the output power from 200W to 1025W.

1. Press

OUTPUT POWER

. The cursor moves to P on the right

hand side of the display.



:1540.000nm

: 200W

2. Type the new value for the output power on the numeric

keypad.



3. Press

ENTER

:1540.000nm P:1025

to end the editing.

Making a Small Change to a Parameter

For small changes to a parameter use

, or the Modify Knob.

EDIT

Select the parameter and then:

1. Press

5,4(5.4)5

EDIT

, or turn the Modify Knob slightly. If you start with

Modify Knob the cursor moves to the digit that was most recently changed.

If no digit was changed before, or if you started with another key, the cursor

moves to the position of the most signicant digit of the parameter.

2. If you want to move the cursor and select another digit to edit, use

4)5

4(5

and

3. Enter the new value for the digit at the cursor on the keypad, or by turning

the Modify Knob. If you have entered the value from the keypad, the cursor

moves to the next digit.

4. Repeat steps 2 and 3 to continue editing the value.

5. When you have nished editing the value, press

ENTER

. The edited value

becomes the new value of the parameter.

Example

To change the wavelength from 1540.000nm to 1542.500nm.

1-6 Getting Started

1. Press

WAVELENGTH

side of the display.

. The cursor moves toon the left hand



:1540.000nm P: 200W

2. Press

. The cursor moves to the most signicant digit of

EDIT

the wavelength value.

:1

540.000nm P: 200W

3. Press

4)5

digit. Press

three times to move to the cursor to the units

425

on the numeric keypad. The units digit

changes, and the cursor moves to the next digit.



:1542.000nm P: 200W

4. Press

Press

on the numeric keypad, to change the tenths digit.

ENTER

to end the editing.



:1542.500nm P: 200W

Setting a Parameter to its Default Value

There is a default softkey that you can use to set a parameter to its default

value.

1. Press

Press

EDIT

NNNNNNNNNNNNNNNNNNNNNN

Default

If You Make a Mistake

If you make a mistake while you are editing a parameter, you can cancel the

editing, and get the previous value for the parameter back by pressing

Alternatively, you can press

NNNNNNNNNNNNNNNNN

Clear

and type in the parameter again.

NNNNNNNNNNNNNNNNNNNN

Cancel

Getting Started 1-7

If the Parameter Will Not Change

If, when you press

ENTER

after editing, the tunable laser source returns

immediately to the previous value for the parameter, then the value you tried to

enter is outside the calibrated range. Press

, and select the

HELP

Input Limits

help topic to see the calibrated range.

A Sample Session

There are two short tasks in this sample session. The rst is to measure the

power of a modulated signal at a single wavelength, and then a wavelength

characteristic at a xed power.

The sample session is written for an HP 8168E/F Tunable Laser Source

an HP 8153A Lightwave Multimeter with an HP 81532A P

is assumed that the power sensor is inserted in channel A). T

ower Sensor (It

o perform the

, and

sample session as described here, you also need a connector interface for the

multimeter (for example, an HP 81000AI), and a patchcord (if you are using

the HP 81000AI, then a Diamond HMS-10/HP/HRL to Diamond HMS-10/HP

patchcord, HP 81109AC).

These same procedures are repeated in \Example 3 - Measuring the Power of

a Modulated Signal" in Chapter 6 and \Example 4 - Measuring a Wavelength

Characteristic" in Chapter 6, where they are performed using the HP-IB.

Measuring the Power of a Modulated Signal

We want to measure the power of a 1540nm signal, modulated by a 100kHz

square wave, at 500W.

1. Make sure that all your connectors and connector interfaces are clean.

2. Make sure that the Optical Output on the laser source is not Active.

3. Connect the output of the laser source to the input of the power sensor (as

shown in the gure below). Make sure that the connector with the orange

strain-relief sleeve is connected to the tunable laser source (the orange

sleeve indicates an angled connector).

1-8 Getting Started

Figure 1-7. Connecting the Instruments for the Sample Session

Typically, you would connect a component to test between the tunable laser

source and the power meter.

4. Make sure that both instruments are powered up.

Note

Normally you also need to be sure that the instruments are

properly warmed up before using the source, or making any

measurements. Here, because the measurements are not critical,

it is okay to proceed immediately to the next step.

Setting the Wavelength

5. On the tunable laser source:

a. Press

b. Make sure that you are setting the wavelength directly.

(Press

WAVELENGTH

NNNNNNNNNNNNNNNNNNNN

nm/GHz

if necessary until there is only one parameter () shown

on the left side of the display).

Press

EDIT

and then

NNNNNNNNNNNNNNNNNNNNNNN

Default

to set the wavelength to 1540.000nm.

6. On the multimeter set the wavelength for the power sensor to 1540.0nm,

set the measurement averaging time to 1s

(

Chan

5!A;

Mode

5!MEAS;4

5!!1540.0nm;

Param

5!T!1s).

Setting the Modulated Power

7. On the tunable laser source:

Getting Started 1-9

a. Press

OUTPUT POWER

b. Make sure that you have a modulated signal selected

(Press

FREQ

c. Make sure that

NNNNNNNNNNNNNNNNNNNN

Mod/CW

if necessary until there are two parameters (

) shown on the right side of the display).

POWER

is selected

POWER

(the label of the selected parameter is displayed in inverse, press

if it is not selected).

d. Make sure that the power is being shown inWatts

(if necessary, press

e. Type 500 on the keypad and press

NNNNNNNNNNNNNNNNN

W/dBm

to change the units).

ENTER

8. On the multimeter, make sure that Watts are selected and that the

instrument is autoranging

(

dBm/W

5!W;

Auto

5!AUTO

9. On the tunable laser source:

NNNNNNNNNNNNNN

a. Press

Freq

b. Type in 100 on the keypad.

c. Make sure that the units are set to kHz

(If necessary, press

d. Press

ENTER

NNNNNNNNNNNNNNNNNNNN

Hz/kHz

to change the units).

and

NNNNNNNNNNNNNNNNN

Power

Figure 1-8.

Tunable Laser Source Display after Setting Up Wavelength and Power

10. Press the button beside the Optical Output, the green LED should be lit to

indicate that the laser is now active.

1-10 Getting Started

You should notice that the power reading on the multimeter is approximately

half the value set on the laser source. This is because the output is modulated

by a square wave with a 50% duty cycle.

Measuring a Wavelength Characteristic

For the second part, we assume that the instruments are in the state given after

the rst task (see Figure 1-8).

We now want to measure the wavelength characteristic by measuring the power

at 1nm steps between 1535nm and 1545nm, at the highest power level possible

that is available over the full sweep range.

11.

On the laser source, press

NNNNNNNNNNNNNNNNNNNN

Mod/CW

to return the laser source to CW

operation.

Setting Up the Wavelength Sweep

12. On the laser source:

a. Press

WAVELENGTH

,and then

b. Type in 1535 on the keypad and press

for the sweep.

c. Type in 1545 on the keypad and press

for the sweep.

d. Type in 1 on the keypad and press

wavelength step for the sweep.

Tunable Laser Source Display during Setting Up for the Wavelength

NNNNNNNNNNNNNNNNNNNNNN



-Sweep

ENTER

Figure 1-9.

Sweep

ENTER

to set the start wavelength

to set the stop wavelength

to set the size of the

Getting Started 1-11

Press

NNNNN

to skip over the dwell parameter.

ENTER

to set the number of times

f. Type in 1 on the keypad and press

that the sweep is to be performed.

13.

On the laser source, press

NNNNNNNNNNNNNNNNNNNNNN

Pmax!P

to set the output power to the highest

value that can be maintained for the full sweep range.

14. On the power meter:

a. Setto 1535nm

5!!1535.0nm).

(

Param

b. Make sure that the parameter cursor is in the units position (that is,at

the second \5").

Performing the Wavelength Characteristic Measurement

15. Make sure that the laser source is still active.

NNNNNNNNNNNNNNNNNNNN

16. On the laser source, press

Manual

17. Read the value for the power at 1535nm on the multimeter.

18. Repeat the following steps at each wavelength in the sweep range

On the laser source, press

b. On the multimeter, increment(press

NNNNNNNNNNNNNN

4*5

c. Read the value for the power at the wavelength on the multimeter.

19.

On the laser source, press

NNNNNNNNNNNNNN

Stop

to end the sweep.

This procedure can be used in practice to measure the wavelength characteristic

of a component.

1-12 Getting Started

Setting Wavelength and Power

This chapter describes how to set the wavelength and the power of the output.

A Summary of the Wavelength and Output Power Hard- and

Softkeys

Setting Wavelength and Power 2-1

Figure 2-1.

A Summary of the additional Output Power Softkeys for the

Attenuator Option

Setting the Wavelength

There are three ways to set the wavelength of the tunable laser source.

You can set the wavelength () directly,

You can set the wavelength from a base wavelength and an oset in the

frequency domain, or

You can set a range of wavelengths for the instrument to \sweep"

Press

Use

WAVELENGTH

NNNNNNNNNNNNNNNNNNNN

nm/GHz

NNNNNNNNNNNNNNNNNNNNNNN



-Sweep

to select how you set the wavelength.

to select the wavelength parameter.

to perform a wavelength sweep.

Setting the Wavelength Directly

You can set the wavelength directly if the display looks like this:

Figure 2-2. Setting the Wavelength Directly

2-2 Setting Wavelength and Power

Press

WAVELENGTH

and

nm/GHz

as necessary to get this display.

See \Changing the Value of a Parameter" in Chapter 1 if you need details on

how to edit parameters.

NNNNNNNNNNNNNNNNNNNN

Example

To set the wavelength to 1505.500nm (on an HP 8168E/F)

1. Press

Press

WAVELENGTH

NNNNNNNNNNNNNNNNNNNN

nm/GHz

, if necessary, until the display looks as shown

in Figure 2-2

3. Type in 1505.5 on the numeric keypad, and press

ENTER

Setting a Relative Wavelength

You use a relative wavelength for heterodyning, for example, when you are

measuring the linewidth of DFB (distributed feedback) lasers.

You can set a relative wavelength if the display looks like this:

Figure 2-3. Setting a Relative Wavelength

NNNNNNNNNNNNNNNNNNNN

and

Press

WAVELENGTH

nm/GHz

The output wavelength () is set from the base wavelength (

as necessary to get to this display.

0) and the

frequency oset (df). The formula for calculating the output wavelength is:



(

0)df+



where c is the speed of light in a vacuum (2.9982108ms-1).

You can edit only the value ofdfdirectly. See \Changing the Value of a

Parameter" in Chapter 1 if you need details on how to edit parameters.

Changing the Base Wavelength

If you want to change

0,

1. setto the value to which you want to set the base wavelength (by

calculatingdf, or by setting the wavelength directly) and then

Setting Wavelength and Power 2-3

press

NNNNNNNNNNNNNNNN

!

Set the base wavelength to 1540.000nm, and then set df, so

Example

that the output wavelength is 1507.5nm (on an HP 8168E/F)

1. Press

WAVELENGTH

NNNNNNNNNNNNNNNNNNN

Press

nm/GHz

(that is, to set the wavelength

EDIT

Press

until the screen looks as shown in Figure 2-2

NNNNNNNNNNNNNNNNNNNNNNN

and then

Default

NNNNNNNNNNNNNNNNNNNN

Press

nm/GHz

, to set a relative wavelength.

NNNNNNNNNNNNNNNN

Press

!

directly

The base wavelength is now set.

6. Calculate the value for df



2:998E8

1507:500E0

1540:000E0

2:998E8

= 4196:980

7. Type in the value for df (4197.0) on the numeric keypad, and

press

ENTER

8. Because of inaccuracies in the value taken for the speed of

light, this gives avalue of 1507.499nm. Use the Modify

Knob to edit the value for df to get=1507.5nm

Performing a Wavelength Sweep

You can perform a wavelength sweep when the screen looks like this

GH z

Figure 2-4. Setting Up for a Wavelength Sweep

NNNNNNNNNNNNNNNNNNNNNNN



Press

WAVELENGTH

and

-Sweep

2-4 Setting Wavelength and Power

as necessary to get this display.

Setting the Wavelength Sweep

There are ve parameters for the wavelength sweep,

start

, the wavelength with which the sweep begins

stop

, the wavelength at which the sweep ends,

step

, the size of the change in wavelength for each step,

dwell

, the amount of time spent at the wavelength during each step, and

cycles

, the number of times the sweep is repeated.

Figure 2-5. The Parameters for a Wavelength Sweep

You move from one parameter to the next, using

ENTER

. Only three of the parameters can be displayed at a time, you scroll the

NNNNN

and

NNNNN

, the Modify Knob,or

other parameters onto the display.

See \Changing the Value of a Parameter" in Chapter 1 if you need details on

how to edit parameters.

Setting the Maximum Power for the Sweep Range

NNNNNNNNNNNNNNNNNNNNNN

Pmax!P

sets the power to the maximum for the selected sweep range.

Alternatively, you can set a power level in the way described in \Setting the

Power".

Setting Wavelength and Power 2-5

Note

If coherence control is enabled, and the uncal power level

cannot be exceeded for the full wavelength range chosen, the

wavelength range is reduced as necessary.

Executing an Automatic Sweep

NNNNNNNNNNNNN

You can perform an automatic sweep if you press

sweep parameters, or if you press

NNNNNNNNNNNNN

Cont

during a manual sweep.

Auto

after setting up the

NNNNNNNNNNNNNNNNN

Press

Pause

to interrupt the sweep. The instrument switches to a manual

sweep (see \Performing a Manual Sweep").

NNNNNNNNNNNNN

Press

Stop

to end the sweep.

Example

Set the instrument to sweep the range 1495nm to 1555nm,

three times, in 1nm steps, stopping for half a second at

each wavelength, at the highest power level available at all

wavelengths.

Press

WAVELENGTH

and then

2. Make sure you are at the

3. Type in 1495 and then

4. Type in 1555 and then

5. Type in 1 and then

6. Type in 0.5 and then

7. Type in 3 and then

9. Enable the optical output, if necessary.

10.

Press

NNNNNNNNNNNNNNNNNNNNNN

Pmax!P

NNNNNNNNNNNNN

Auto

, to set the power.

, to run the application.

ENTER

Performing a Manual Sweep

You can perform a manual sweep if you press

sweep parameters, or if you press

NNNNNNNNNNNNNNNNN

Pause

during an automatic sweep. During a

manual sweep the display looks as follows:

NNNNNNNNNNNNNNNNNNNNNNN



-Sweep

start

ENTER

, to set the start wavelength.

, to set the stop wavelength.

, to set the step size.

, to set the dwell time.

, to set the number of cycles.

parameter.

NNNNNNNNNNNNNNNNNNNN

Manual

after setting up the

2-6 Setting Wavelength and Power

Press

NNNNNNNNNNNNNN

NNNNNNNNNNNNN

Cont

NNNNNNNNNNNNNN

Stop

Figure 2-6. Performing a Manual Sweep

to move on to the next wavelength step

to move back to the previous wavelength step.

to continue with an automatic sweep, from the current wavelength.

to end the sweep.

Setting Wavelength and Power 2-7

Setting the Power

The laser output can be either

a continuous wave (CW), xed-amplitude signal,

a modulated signal, or

a signal with increased linewidth (coherence control).

Attenuator

If you have the built in attenuator, there are two power modes

for both the xed-amplitude, the modulated, and the increased

linewidth signals.You can either

specify the output power (Power Mode), or

specify the laser power and the attenuation (Attenuation

Mode).

The two modes are separate, the values set in one mode do not

aect the values set in the other.

NNNNNNNNNNNNNNNNNNNN

Press

OUTPUT POWER

to select the output power parameter. Use

Mod/CW

choose CW, modulated, or coherence control.

NNNNNNNNNNNNNNNNNNNNNNN

Attenuator

If you have the optional attenuator installed, use

PowMode

choose between Power Mode (specifying the output power) and

Attenuation Mode (specifying the laser power and attenuation).

Setting the Output Power of a CW Signal

You can set the output power of a CW signal if the display looks like this:

Figure 2-7. Setting the Output Power of a CW Signal

NNNNNNNNNNNNNNNNNNNN

Press

OUTPUT POWER

Mod/CW

2-8 Setting Wavelength and Power

and

NNNNNNNN

as necessary to get to this display.

See \Changing the Value of a Parameter" in Chapter 1 if you need details on

how to edit parameters.

NNNNNNNNNNNNNNNNN

You can change the units by pressing

W/dBm

Attenuator

If you have the optional attenuator installed, you may need to

NNNNNNNNNNNNNNNNNNNNNNN

press

PowMode

to get the display shown above.

Setting Power and Attenuation

Attenuator

If you have the optional attenuator installed, you can also set

the output power by setting rst the laser output power, and

then setting the amount of attenuation.

NNNNNNNNNNNNNNNNNNNNNNN

Press

PowMode

from the screen shown in Figure 2-7 to change

to the Attenuation Mode.

Press

NNNNNNNNNNN

Att

to select the attenuation parameter. Press

NNNNNNNNNNNNNN

Pref

select the laser output power.

What is Excessive Power?

EXCESSIVE

message indicates that the value you have set for the output

power is larger than the laser diode is capable of producing at this wavelength.

The instrument sets the output power as high as possible; it is this actual output

power that is shown as part of the

Note

If the chosen value is simultaneously too low for the coherence

control, if you are also using this, the

EXC

EXCESSIVE

message.

EXCESSIVE

is shortened

The Analog Output

The Analog Output, on the front panel of the instrument, outputs a dc level

that is proportional to the laser output power. The relationship between this

voltage level and the output power is not calibrated, but is approximately 1mV

for each 1W.

Setting Wavelength and Power 2-9

Attenuator

If you have the optional attenuator installed, the Analog Output

signal depends on the power mode you have chosen.

In Power Mode the laser output power, and therefore the

Analog Output signal, is not linearly proportional to the output

power. This is because the actual output optical power is

derived by the optimum combination of the laser output power

and the attenuation.

In Attenuation Mode the relationship between the Pref and

the voltage level is approximately 1.35mV for each 1W. (The

dierence between this value and that of the tunable laser

source without the attenuator is due to the insertion loss of the

attenuator). This value is only proportional to the output power

if the attenuation remains constant. Here, the attenuator adds a

constant oset to the voltage level.

Example

To set the power to -10dBm.

1. Press

OUTPUT POWER

NNNNNNNNNNNNNNNNNNNN

Press

Mod/CW

as shown in Figure 2-7.

NNNNNNNNNNNNNNNNN

Press

W/dBm

, and

, if necessary, so that the power is displayed in

NNNNNNNN

if necessary, so that the display looks

dBm.

4. Type -10 on the numeric keypad, and press

ENTER

Setting a Modulated Signal

There are two ways of modulating the amplitude of the optical output.

Using the internal modulation, and

using external modulation.

2-10 Setting Wavelength and Power

Using the Internal Modulation

The internal modulating source is a square wave with a 50% duty-cycle.You can

set both the amplitude and the frequency of this signal. The amplitude is set by

the power parameter. This is the maximum output power of the output signal;

at the minimum, nothing is output.

Figure 2-8. The Modulated Signal

Setting the Output Power of a Modulated Signal

You can set the output power of a modulated signal if the display looks like this:

Figure 2-9. Setting the Output Power of an Internally Modulated Signal

Press

OUTPUT POWER

NNNNNNNNNNNNNNNNNNNN

Mod/CW

, and

NNNNNNNNNNN

Int

as necessary to get to this display.

See \Changing the Value of a Parameter" in Chapter 1 if you need details on

how to edit parameters.

NNNNNNNNNNNNNNNNN

You can change the units by pressing

W/dBm

The notes above about excessive power, and the analog output apply also to the

power of a modulated signal.

Setting the Frequency of a Modulated Signal

You can also set the frequency of a modulated signal from the display shown

above. Press

NNNNNNNNNNNNN

Freq

to select the parameter. See \Changing the Value of a

Parameter" in Chapter 1 if you need details on how to edit parameters.

NNNNNNNNNNNNNNNNNNNN

You can change the units by pressing

The new units come into eect when you press

Hz/kHz

while you are editing the value.

ENTER

Setting Wavelength and Power 2-11

The Modulation Output

The Modulation Output on the front panel outputs a version of the modulating

signal that has the same frequency and phase as the modulating signal, but has

a xed, TTL-level amplitude.You can use this to synchronize your external

measuring equipment to the tunable laser source.

To allow for your possible sychronization requirements, there are two ways

in which the signal can be output. Either the signal is combined with the

laser-ready signal, so that the output is kept low when there is no optical

signal being output (for example, while the laser is settling after a change of

wavelength). Or the modulation signal is output all the time. This is set by the

System

NNNNNNNNNNNNNNNNNNNN

MODOUT

parameter (see \Setting the Modulation Output" in Chapter 3).

Example

Set the frequency of the modulated output to 300Hz.

1. Press

4. Type 300 on the numeric keypad.

OUTPUT POWER

NNNNNNNNNNNNNNNNNNN

Press

Mod/CW

looks as shown in Figure 2-9.

NNNNNNNNNNNNNN

Press

Freq

, and

NNNNNNNNNNNNNNNNNNNN

Press

ENTER

Hz/kHz

, if necessary, to set the units to Hz, and press

NNNNNNNNNN

Int

if necessary, so that the display

Using External Modulation

The external modulating source can be any signal of up to 5Vpp.A5Vppsignal

causes 15% modulation of the power of the optical output signal.

Figure 2-10. External Modulation and Output Power

2-12 Setting Wavelength and Power

Setting the Output Power of a Modulated Signal

You can set the output power of a modulated signal if the display looks like this:

Figure 2-11. Setting the Output Power of an Externally Modulated Signal

Press

OUTPUT POWER

NNNNNNNNNNNNNNNNNNNN

Mod/CW

, and

NNNNNNNNNNN

Ext

as necessary to get to this display.

See \Changing the Value of a Parameter" in Chapter 1 if you need details on

how to edit parameters.

NNNNNNNNNNNNNNNNN

You can change the units by pressing

W/dBm

The notes above about excessive power, and the analog output apply also to the

power of a modulated signal.

The Modulation Input

The Modulation Input on the front panel is where you input your modulating

signal.

Using Coherence Control

Enabling the coherence control increases the linewidth of the optical output

signal to between 50 and 500MHz (typically). This drastically reduces

interference eects and therefore improves the power stability in sensitive test

setups.

Setting the Output Power of a Coherence Control Signal

You can set the output power of a coherence controlled signal if the display

looks like this:

Setting Wavelength and Power 2-13

Figure 2-12. Setting the Output P

NNNNNNNNNNNNNNNNNNNN

Mod/CW

Press

OUTPUT POWER

ower of a Coherence Controlled Signal

NNNNNNNNNNNNNNNNNNNNNNN

, and

CohCtrl

as necessary to get to this

display.

See \Changing the Value of a Parameter" in Chapter 1 if you need details on

how to edit parameters.

NNNNNNNNNNNNNNNNN

You can change the units by pressing

W/dBm

The notes above about excessive power, and the analog output apply also to the

power of a coherence controlled signal.

The Coherence Control Uncal Power

At any particular wavelength, coherence control is only available with the

specied linewidth, above a level known as the Coherence Control Uncalibrated

Power, and below the Maximum Power level (that is, in the area between the

two curves in the diagram). The message

CC UNCAL

indicates that the laser

power is not high enough to provide the specied linewidth. The linewidth is

still broadened.

Figure 2-13.

The Coherence Control Uncalibrated Power and the Maximum Power Level

2-14 Setting Wavelength and Power

Other Functions

This chapter describes how to save and recall measurement settings for the

tunable laser source, and how to use the system functions of the instrument.

Storing and Recalling Instrument Settings

The

SETTING

displays look as follows:

There are seven settings:

key gives you access to the instrument settings displays. These

Figure 3-1. User Setting Number 1

Attenuator

the Actual Setting, which is the setting being used by the instrument,

the Default Setting, and

ve user settings.

When you have the optional attenuator installed, then the

setting also includes the laser output power (Pref), the

attenuation (Att), and the power mode (PowMode, or AttMode).

Other Functions 3-1

Note

The Default Setting does

not

contain-Sweep information. All

other settings contain this information, although it is not shown

on the display.

Figure 3-2. Summary of the Setting Hard- and Softkeys

Use

NNNNNNNNNNNNNN

and

NNNNNNNNNNNNNN

to move between the dierent setting displays.

NNNNNNNNNNNNNNNNNNNNNNN

Press

Default

to reset the Actual Setting to default values.

NNNNNNNNNNNNNNNNNNNN

Press

Recall

to recall the Default Setting, or the currently displayed user

setting for use as the Actual Setting (overwriting the Actual Setting).

NNNNNNNNNNNNNNNNN

Press

Store

to store the Actual Setting to the currently displayed user setting

(overwriting the user setting).

Using the System Utilities

Press

SYSTEM

to access conguration information for the tunable laser source.

You get the following screen:

3-2 Other Functions

Figure 3-3. The System Screen

Figure 3-4. Summary of the System Hard- and Softkeys

There are not enough function keys under the display for all the system

functions, therefore they have been divided into two sections.You change from

one section to the other by pressing the

NNNNNNNNNNNNNN

Softkey.

Switching the Instrument into Stand-By

Increasing the Lifetime of the Display

Normally the display is on at all times. If you want to switch o the display

(and the laser), but keep the instrument running (for example, to prevent

Other Functions 3-3

display burn-in, but to keep the heat chamber up to temperature), press

NNNNNNNNNNNNNNNNNNNNNNN

StandBy

(you may have to press

NNNNNNNNNNNNNN

to get to this softkey).

While the instrument is in standby mode the laser is switched o, and the word

standby is ashed on the screen. Press any key to reactivate the instrument.

Setting the HP-IB Address

NNNNNNNNNNNNNN

Press

HPIB

to select the parameter for setting the HPIB address (you may have

to press

NNNNNNNNNNNNNN

to get to this softkey).

See \Changing the Value of a Parameter" in Chapter 1 if you need details on

how to edit parameters.

The default HP-IB address is 24.

Setting the Modulation Output

Press

NNNNNNNNNNNNNNNNNNNN

MODOUT

to toggle the modulation output (you may have to press

NNNNNNNNNNNNNN

get to this softkey). The two possible values are

FRQ&RDY, where the modulation signal is combined with the laser-ready

signal, so that the output is kept low when there is no optical signal being

output (for example, while the laser is settling after a change of wavelength),

and

FRQ, where the modulation signal is output all the time.

Getting Information about the Instrument

NNNNNNNNNNNNNN

Press

Info

for information on the rmware revision, serial number and the

date of the last calibration of your instrument (you may have to press

NNNNNNNNNNNNNN

get to this softkey).

Setting the Date and Time

Press

NNNNNNNNNNNNNN

Date

to set the date (you may have to press

NNNNNNNNNNNNNN

to get to this softkey).

You can type in the six numbers for the date directly from the numeric keypad,

or you can use the arrow keys and the numeric keypad to edit the date. The

date is changed when you press the

Enter

key.

The date is in the format month/day/year.

3-4 Other Functions

You cannot use the Modify Knob for editing the date.

Press

NNNNNNNNNNNNNN

Time

to set the time (you may have to press

NNNNNNNNNNNNNN

to get to this softkey).

You can type in the four numbers for the time directly from the numeric

keypad, or you can use the arrow keys and the numeric keypad to edit the time.

The time is changed when you press the

Enter

key.

The time is in the format hours:minutes.

You cannot use the Modify Knob for editing the time.

Performing a Selftest

NNNNNNNNNNNNNNNNNNNNNNN

Press

SelfTst

to start the internal instrument self-test. The instrument

performs a full self-test, indicating after each test, the test that has just been

performed, and the result (



P1 Board indicates the test of the rst microprocessor board.



P2 Board indicates the test of the second microprocessor board.

passedorfailed

Cal. Data is the test of the calibration data, which is stored in the

instrument.

HW-Interface tests the hardware interface.

ADC is the test of the analog to digital converter

Laser Board tests the laser driver board.

Motor 1 tests the rst of the two motors used to control the tuning of

the laser.

Motor 2 tests the second of the two motors used to control the tuning of

the laser.

Attenuator

Motor 3 tests the motor used to control the attenuation.

When the test is completed, the message

Selftest

.... ...

passed

is shown

on the display. If the instrument fails a selftest, the end of the test is signalled

by three short beeps and the message

Selftest

.... ...

failed

is displayed.

Even if the instrument fails the selftest, it will continue to operate as far as

possible.

Other Functions 3-5

Auxiliary Functions

There are four or ve auxiliary functions, accessed by

AUX

NNNNNNNNNNNNNNNNNNNNNNN

Pmax()

, the power characteristic (maximum power as a function of the

wavelength),

NNNNNNNNNNNNNNNNNNNNNN

Peak

, the setting for maximum output power,

NNNNNNNNNNNNNN

PACT

, the Passive Component Test,

NNNNNNNNNNNNNNNNNNNNNNN

Realign

,Automatic Realignment, and

NNNNNNNNNNNNNNNNNNNN

Secure

, the instrument lock (8168F only).

Figure 3-5. Auxiliary Functions (8167A, 8168D/E)

Figure 3-6. Auxiliary Functions (8168F)

Viewing the Power as a Function of Wavelength

NNNNNNNNNNNNNNNNNNNNNNN

Press

Pmax()

to get the graph of the maximum power as a function of the

wavelength. This graph is drawn from the calibration data for the instrument.

You can view the graph for the continuous wave power as a function of the

wavelength if you make sure that the CW is selected for the output power.If

coherence control is enabled, you will also be able to see the coherence control

3-6 Other Functions

uncal power level. Similarly, to view the maximum power for a modulated

signal, you must make sure that Mod is selected.

There is a cursor on this graph, and the values for the wavelength position of

this cursor, and the maximum power that can be output at this wavelength are

given at the right of the display. If coherence control is enabled, the value for

the minimum power that you should select is also given here.

You can move the cursor with the Modify Knob, or the

4(5

, and the

4)5

keys.

Setting the Peak Power

The peak power is the highest power that the instrument can deliver.To set

the output for peak power, press

NNNNNNNNNNNNNNNNNNNNNN

Peak

. This changes the wavelength to

the lowest wavelength at which the peak power can be achieved, and sets the

power to this peak value.

Passive Component Test (PACT)

See separate manual 08168-91051.

Automatic Realignment

NNNNNNNNNNNNNNNNNNNNNNN

Press

Realign

to request automatic realignment. This realigns the laser cavity

after Laser Protection. You should use Automatic Realignment if you have

already tried reactivating the laser and reducing the power, and this has been

unsuccessful.

You should not use Automatic Realignment when the laser is stabilizing.

Automatic Realignment is available on all 8168D/E/F models, but only 8167A

models with serial numbers greater than 3424G00176.

NNNNNNNNNNNNNNNNNNNNNNN

After pressing

Laser will be active while realigning.

Please

output to avoid damage.

Realignment will take

Realign

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

disconnect

, you get the following message:

any device from

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

approx tt minutes

NNNNNNNN

where

is the approximate time that Realignment will take. This will be

roughly 15 minutes, although actual time taken depends on the wavelength

range of the instrument.

Other Functions 3-7

Press the

Start

softkey. The message

Running

is ashed in the Display

window. The Display also shows the estimated time before realignment is

complete. The extreme right softkey oers you the chance to abort, and may be

pressed at any time.

Figure 3-7. Auto Realignment

After realignment, one of the following messages appears in the Display

window:

NNNNNNNNNNNNNNNNN

Abort by user

{ you have pressed the

Abort

softkey during realignment. The

laser cavity has not been realigned.

A power down interrupted Auto Realignment at a critical moment

Automatic Realignment has been interrupted by a power down. The laser cavity

has not been realigned. Continue by pressing the

Realignment OK

{ the laser cavity has been realigned successfully with laser

NNNNNNNNNNNNNNNNNNNNNNN

Realign

NNNNNNNNNNNNNN

Exit

{

softkey.

protection occurring for at most 1 wavelength point over the tuning range.

No improvement

{ the laser cavity has been realigned, but laser protection has

occurred for more than 1 wavelength point over the tuning range. It is still safe

to continue.

Realignment impossible, contact service

{ the laser cavity cannot

be realigned because of a serious error. This error is unlikely to be directly

concerned with realignment. Contact service and do not continue.

NNNNNNNNNNNNNNNNN

Not allowed during stabilizing

{ you tried to

Start

an operation while

stabilizing when the working temperature is too low. Please wait until it has

stabilized. See \Stabilizing" in Appendix A for more information.

Stabilizing occurred try again later

{ the instrument has resumed

stabilizing. Realignment is not possible at present.

3-8 Other Functions

Secure

NNNNNNNNNNNNNNNNNNNN

Press

Secure

from using this Laser Safety Class IIIb instrument (8168F only). When you press

NNNNNNNNNNNNNNNNNNNN

Secure

, you see the following screen:

to lock the instrument. This is to prevent unauthorized persons

Figure 3-8. \Secure" screen

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

You may also see the message

default pwd: 8168, please change it!

If you see this message, your password is still 8168 (the default). To prevent

unauthorized persons using the instrument, you should change the password

(see below).

The \Secure" screen oers you the following facilities:

NNNNNNNNNNNNNN

Lock

: lock the instrument,

NNNNNNNNNNNNNNNNNNNNNNN

ChngPwd

NNNNNNNNNNNNN

Exit

: change the password,

: return to the main screen.

Lock the Instrument

NNNNNNNNNNNNNN

When you press

Lock

, you see the following screen:

Other Functions 3-9

Figure 3-9. \Secure: Lock Instrument" screen

To lock the screen, you enter the 4-gure password using the DATA keys. The

default password is 8168, but this can be changed by pressing

the \Secure" screen (see below).

When you enter the correct password, you see the following screen:

Figure 3-10. \Secure" screen - instrument is locked

The laser is switched o as soon as the instrument is locked.

NNNNNNNNNNNNNNNNNNNN

Press

Unlock

to unlock the instrument. You get the following screen:

NNNNNNNNNNNNNNNNNNNNNN

ChngPwd

from

Figure 3-11. \Secure: Unlock Instrument" screen

Enter the correct password to return to the \Secure" screen (Figure 3-8)

3-10 Other Functions

Change the Password

NNNNNNNNNNNNNNNNNNNNNNN

Press

ChngPwd

Enter the 4-gure password, using the DATA keys. If you have not changed the

password before, the default is 8168. When you enter the password correctly

you get the following screen:

from the \Secure" screen. You see the following screen:

Figure 3-12. \Secure: Change Password" screen

Figure 3-13.

\Secure: Change Password": Enter new password

Enter a new 4-gure password. You will be asked to verify this number:

Figure 3-14.

\Secure: Change Password": Enter new password again

Other Functions 3-11

When you enter the same number again, the password is changed and you

return to the \Secure" screen (Figure 3-8). This new password is used to lock

the instrument (see above), and you must enter it when you turn on the

machine (see \Starting the 8168F" in Chapter 1).

If you forget your password, please contact Hewlett-Packard.

3-12 Other Functions

Programming the Tunable Laser Source

This chapter gives general information on how to control the tunable laser

source remotely. Descriptions for the actual commands for the tunable laser

source are given in the following chapters. The information in these chapters is

specic to the tunable laser source, and assumes that you are already familiar

with programming the HP-IB.

HP-IB Interface

The interface used by the tunable laser source is the HP-IB (Hewlett-Packard

Interface Bus).

This is the interface used for communication between a controller and an

external device, such as the tunable laser source. The HP-IB conforms to IEEE

standard 488-1978, ANSI standard MC 1.1 and IEC recommendation 625-1.

If you are not familiar with the HP-IB, then refer to the following books:

Hewlett-Packard Company.

Bus

, 1987.

The International Institute of Electrical and Electronics Engineers.

Tutorial Description of Hewlett-Packard Interface

IEEE

Standard 488.1-1987, IEEE Standard Digital Interface for Programmable

Instrumentation

The International Institute of Electrical and Electronics Engineers.

. New York, NY, 1987

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

To obtain a copy of either of these last two documents, write to:

The Institute of Electrical and Electronics Engineers, Inc.

345 East 47th Street

New York, NY 10017

USA.

Remote Operation 4-1

In addition, the commands not from the IEEE-488.2 standard, are dened

according to the Standard Commands for Programmable Instruments (SCPI).

For an introduction to SCPI, and SCPI programming techniques, refer to the

following documents:

Hewlett-Packard Press (Addison-Wesley Publishing Company, Inc.).

Beginners Guide to SCPI

The SCPI Consortium.

Published periodically by various publishers.To obtain a copy of this manual,

contact your Hewlett-Packard representative.

The tunable laser source interfaces to the HP-IB as dened by the IEEE

Standards 488.1 and 488.2. The table shows the interface functional subset that

the tunable laser source implements.

Mnemonic Function

SH1 Complete source handshake capability

AH1 Complete acceptor handshake capability

T6 Basic talker; serial poll; unaddressed to talk if addressed to listen

L4 Basic listener; unaddressed to listen if addressed to talk; no listen only

SR1 Complete service request capability

RL1 Complete remote/local capability

PP0 No parallel poll capability

DC1 Device clear capability

DT0 No device trigger capability

C0 No controller capability (Controller capability to be implemented)

. Barry Eppler. 1991.

Standard Commands for Programmable Instruments

Table 4-1. HP-IB Capabilities

4-2 Remote Operation

Setting the HP-IB Address

You can only set the HP-IB address from the front panel. See \Setting the HP-IB

Address" in Chapter 3.

The default HP-IB address is 24.

Returning the Instrument to Local Control

If the instrument has been operated in remote the only key you can use is

NNNNNNNNNNNNNNNN

Local

. This key returns the instrument to local control.

NNNNNNNNNNNNNNNN

Local

does not

operate if local lockout has been enabled.

How the Tunable Laser Source Receives and

Transmits Messages

The tunable laser source exchanges messages using an input and an output

queue. Error messages are kept in a separate error queue.

How the Input Queue Works

The input queue is a FIFO queue (rst-in rst-out). Incoming bytes are stored in

the input queue as follows:

1. Receiving a byte:

a. Clears the output queue.

b. Clears Bit 7 (MSB).

2. No modication is made inside strings or binary blocks. Outside strings and

binary blocks, the following modications are made:

a. Lower-case characters are converted to upper-case.

b. The characters 0016to 0916and 0B16to 1F16are converted to spaces

(2016).

c. Two or more blanks are truncated to one.

Remote Operation 4-3

3. An EOI (End Or Identify) sent with any character is put into the input queue

as the character followed by a line feed (LF,0A

only one LF is put into the input queue.

4. The parser starts if the LF character is received or if the input queue is full.

Clearing the Input Queue

Switching the power o, or sending a Device Interface Clear signal, causes

commands that are in the input queue, but have not been executed to be lost.

). If EOI is sent with a LF,

The Output Queue

The output queue contains responses to query messages. The tunable laser

source transmits any data from the output queue when a controller addresses

the instrument as a talker.

Each response message ends with a carriage return (CR, 0D16) and a LF (0A16),

with EOI=TRUE. If no query is received, or if the query has an error, the

output queue remains empty.

The Message Available bit (MAV, bit 4) is set in the Status Byte register

whenever there is data in the output queue.

The Error Queue

The error queue is 30 errors long. It is a FIFO queue (rst-in rst-out). That is,

the rst error read is the oldest error to have occurred. A new error is only put

into the queue if it is not already in it.

If more than 29 errors are put into the queue, the message '-350<Queue

Overow>' is placed as the last message in the queue.

4-4 Remote Operation

Some Notes about Programming and Syntax Diagram

Conventions

A program message is a message containing commands or queries that you send

to the tunable laser source. The following are a few points about program

messages:

You can use either upper-case or lower-case characters.

You can send several commands in a single message. Each command must be

separated from the next one by a semicolon (;).

You end a program message with a line feed (LF) character, or any character

sent with End-Or-Identify (EOI).

You can use any valid number/unit combination.

Example

1500nm, 1.5m and 1.5e-6m are all equivalent.

If you do not specify a unit, then the default unit is assumed. The default

unit for the commands are given with command description in the next

chapter.

Short Form and Long Form

The instrument accepts messages in short or long forms

message

message is

:STATUS:OPERATION:ENABLE 768

:STAT:OPER:ENAB 768

is in long form, the short form of this

.For example, the

In this manual the messages are written in a combination of upper and lower

case. Upper case characters are used for the short form of the message.For

example, the above command would be written

:STATus:OPERation:ENABle

The rst colon can be left out for the rst command or query in your message.

That is, the example given above could also be sent as

STAT:OPER:ENAB 768

Command and Query Syntax

All characters not between angled brackets must be sent exactly as shown.

The characters between angled brackets (<...>) indicate the kind of data that

you should send, or that you get in a response.You do not type the angled

brackets in the actual message. Descriptions of these items follow the syntax

description. The most common of these are:

Remote Operation 4-5

string is ascii data. A string is contained between a " at the start and the

end, or a ' at the start and the end.

value is numeric data in integer (12), decimal (34.5) or exponential format

(67.8E-9).

wsp is a white space.

Other kinds of data are described as required.

The characters between square brackets ([ . . . ]) show optional information that

you can include with the message.

The bar (j) shows an either-or choice of data, for example,ajbmeans eitheraor

, but not both simultaneously.

Extra spaces are ignored; they can be inserted to improve readability

4-6 Remote Operation

Remote Commands

This chapter gives a list of the HP 8167A/8D/8E/8F Remote commands, for use

with the HP-IB.

In the remote command descriptions the parts given in upper-case characters

must be given. The parts in lower-case characters can also be given, but they

are optional.

Units

The units and all the allowed mnemonics are given in the table below

Table 5-1. Units and Allowed Mnemonics

Unit Default Allowed Mnemonics

deciBel/1mW

Hertz

meter

Watt

Where units are specied with a command, only the Default is shown, by the

full range of mnemonics can be used.

DBM DBM,DBMW

HZ HZ,KHZ,MAHZ,GHZ,THZ

M PM,NM,UM,MM,M

Watt PW,NW,UW,MW,W

Remote Commands 5-1

Command Summary

Table 5-2. Common Command Summary

Command Parameter/Response Min Max Function

*CLS

*ESE

*ESE?

*ESR?

*IDN?

value

string

0 255 Standard Event Status Enable Command

0 255 Standard Event Status Enable Query

0 255 Standard Event Status Register Query

*OPC

*OPC?

*OPT?

*RCL

value

string

location

0 5 Recall Instrument Setting

*RST

*SAV

*SRE

*SRE?

*STB?

*TST?

location

value

1 5 Save Instrument Setting

0 255 Service Request Enable Command

0 255 Service Request Enable Query

0 255 Read Status Byte Query

0 65535 Self Test Query

*WAI

Clear Status Command

Identication Query

Operation Complete Command

Operation Complete Query

Options Query

Reset Command

Wait Command

5-2 Remote Commands

Table 5-3. Command List

Command Parameter

Unit Min Max Default Notes

Response

:DISPlay

:ENABle OFFjONj0j1 1

:ENABle? 0j1

:LOCK OFFjONj0j1,<value

:LOCK? 0j1

:OUTPut

[

:STATe

]

[

:STATe]? 0j1

[

:SOURce

]

OFFjONj0j1 0

:AM

:INTernal

:FREQuency

:FREQuency?

MINjDEFjMAX

value>j

value

MINjDEFjMAX HZ

250 300 000 80 000

:SOURce INTjINT1jINT2jEXTj0j1j2 0

:SOURce? 0j1j2

:STATe OFFjONj0j1 0

:STATe? 0j1

[

:SOURce

]

:MODout FRQjFRQ&RDYj0j1

[

:SOURce

]

:MODout? 0j1

[

:SOURce

]

:POWer

:ATTenuation

:ATTenuation?

MINjDEFjMAX

value>j

value

MINjDEFjMAX[DB

] 40.0dBmy0.0dBmy0.0dBm

:AUTO OFFjONj0j1 0

:AUTO? 0j1

:DARK OFFjONj0j1 0

:DARK? 0j1

[

:LEVel

]

[

:IMMediate

[

:AMPlitude]<

]

value>j

MINjDEFjMAX DBM

-10dBm

-4dBmy-7.0dBm

100Wy398Wy200W

Attenuator Option

DBM

-50dBmy-5.5dBmy-7.0dBm

[

:AMPlitude]?<value

MINjDEFjMAX<value

DBM,W

10nW

300Wy200W

:UNIT DBMjDBMWjW DBM

:UNIT? DBMjW

password

Remote Commands 5-3

Table 5-3. Command List (continued)

Command Parameter

Unit Min Max Default Notes

Response

[

:SOURce

]

:WAVElength

[

:CWj:FIXED]<

value>j

MINjDEFjMAX M

HP 8167A

1280nmy1330nmy1310nm

HP 8168D

1490nmy1565nmy1540nm

HP 8168E

1475nmy1575nmy1540nm

HP 8168F

1450nmy1590nmy1540nm

[

:CWj:FIXED]?<value

MINjDEFjMAX<value

:REFerence?

value

:DISPlay

:FREQuency

:FREQuency?

value

:STATus

:OPERation

[

:EVENt]?

:CONDition?

:ENABle

:ENABle?

:NTRansition<value

:NTRansition?<value

:PTRansition<value

:PTRansition?<value

value

:QUEStionable

[

:EVENt]?

:CONDition?

:ENABle

:ENABle?

:NTRansition<value

:NTRansition?<value

:PTRansition<value

:PTRansition?<value

value

:PRESet

5-4 Remote Commands

Table 5-3. Command List (continued)

Command Parameter

Response

:SYSTem

:DATe

:DATe?

:ERRor?

:TIMe

:TIMe?

value>,<value>,<value

value>/<value>/<value

value

value>,<value>,<value

value>:<value>:<value

:TRACe

:CATalog?

string

:POINts?

trace name

[

:DATa]?

trace name

value

value>,<value>,

Unit Min Max Default Notes

Year,Month,Day

Year/Month/Day

-32768 32767

Hour,Minute,Second

Hour:Minute:Second

trace names

the number of points

... X- and Y-value

for each point

WAVEACT

These are specied minimum and maximum values.Actual values depend on

value

Wavelength in meters

the calibration of the instrument.

The Common Commands

The IEEE 488.2 standard has a list of reserved commands, called common

commands. These are the commands that start with an asterisk. Some of these

commands must be implemented by any instrument using the standard, others

are optional. The tunable laser source implements all the necessary commands,

and some optional ones. This chapter describes the implemented commands.

Common Status Information

There are four registers for the common status information. Two of these are

status-registers and two are enable-registers. These registers conform to the

IEEE Standard 488.2-1987

.You can nd further descriptions of these registers

under \*ESE", \*ESR?", \*SRE", and \*STB?".

The following gure shows how the registers are organized.

Remote Commands 5-5

Figure 5-1. Common Status Registers

The questionable and operation status trees are described in \:STATus

Commands".

Note

SRQ, The Service Request

A service request (SRQ) occurs when a bit in the Status Byte register goes from

0!1

The Request Service (RQS) bit is set to1at the same time that the SRQ is

caused. This bit can only be reset by reading it by a serial poll. The RQS bit is

5-6 Remote Commands

AND the corresponding bit in the Service Request Enable Mask is set.

Unused bits in any of the registers return 0 when you read

them.

not aected by the condition that caused the SRQ. The serial poll command

transfers the value of the Status Byte register to a variable.

*CLS

Syntax

Denition

Example

*ESE

Syntax

Denition

*CLS

The *CLS command clears the following:

Error queue

Standard event status register (ESR)

Status byte register (STB)

After the

*CLS

command the instrument is left waiting for the

next command. The instrument setting is unaltered by the

command, though

*OPC/*OPC?

actions are canceled.

If the *CLS command occurs directly after a program message

terminator, the output queue and MAV, bit 4, in the status byte

zero.

OUTPUT 724;"*CLS"

*ESE<wsp><value

0value255

The

*ESE

command sets bits in the standard event status enable

event status register (ESR).

The register is cleared:

At power-on

By sending a value of zero

The register is not changed by the

*RST

and

*CLS

commands.

Remote Commands 5-7

BIT MNEMONIC BIT VALUE

7 Power On 128

6 User Request 64

5 Command Error 32

4 Execution Error 16

3 Device Dependent Error 8

2 Query Error 4

1 Request Control 2

0 Operation Complete 1

The Event Status Enable Register

*ESE?

Example

*ESR?

Syntax

Denition

The standard event status enable query returns the contents of

the standard event status enable register.

OUTPUT 724;"*ESE 21"

OUTPUT 724;"*ESE?"

ENTER 724; A$

*ESR?

The standard event status register query returns the contents of

the standard event status register. The register is cleared after

being read.

0contents255

5-8 Remote Commands

BITS MNEMONICS BIT VALUE

7 Power On 128

6 User Request 64

5 Command Error 32

4 Execution Error 16

3 Device Dependent Error 8

2 Query Error 4

1 Request Control 2

0 Operation Control 1

The Standard Event Status Register

Example

*IDN?

Syntax

Denition

HP8167AorHP8168DorHP8168EorHP8168F

Example

OUTPUT 724;"*ESR?"

ENTER 724; A$

*IDN?

The identication query commands the instrument to identify

itself over the interface.

Response:

HEWLETT-PACKARD, HP8167A, mmmmmmmmmm, n.n.n

HEWLETT-PACKARD

: manufacturer

: instrument model number

mmmmmmmmmm

: serial number (not supplied)

n.n.n

: rmware revision level

DIM A$ [100]

OUTPUT 724;"*IDN?"

ENTER 724; A$

Remote Commands 5-9

*OPC

Syntax

Denition

*OPC

The instrument parses and executes all program message units

in the input queue and sets the operation complete bit in the

standard event status register (ESR). This command can be used

to avoid lling the input queue before the previous commands

have nished executing.

*OPC?

This query causes all the program messages in the input queue

to be parsed and executed. Once it has completed it places an

ASCII '1' in the output queue. There is a short delay between

interpreting the command and putting the '1' in the queue.

Example

OUTPUT 724;"*CLS;*ESE 1;*SRE 32"

OUTPUT 724;"*OPC"

OUTPUT 724;"*CLS;*ESE 1;*SRE 32"

OUTPUT 724;"*OPC?"

ENTER 724;A$

*OPT?

Syntax

Denition

*OPT?

This query returns a string with the options installed in the

tunable laser source.

If the Passive Component Test software is available, the rst

position in the option string is

not available, the rst position returns0.

If the optional attenuator is installed, the third position in the

option string is

position returns0.

If Coherence Control is available, the fourth position in the

option string is

fourth position returns0.

Example

OUTPUT 724;"*OPT?"

ENTER 724;A$

5-10 Remote Commands

Passive Component Test

ATTENUATOR

. If it is not installed, the third

COHERENCE CONTROL

.Ifitis

. If it is not available, the

*RCL

Syntax

Denition

Example

*RST

Syntax

Denition

*RCL<wsp

location

0location5

An instrument setting from the internal RAM is made the actual

instrument setting.

You can recall user settings from locations 1-5. See \*SAV".

Location 0 contains the default setting, which is the same as

that obtained by

*RST

OUTPUT 724;"*RCL 3"

*RST

The reset setting (default setting) stored in ROM is made the

actual setting.

Instrument state: the instrument is placed in the idle state

awaiting a command.

The following are not changed:

HP-IB (interface) state

Instrument interface address

Output queue

Service request enable register (SRE)

Standard event status enable register (ESE)

The commands and parameters of the reset state are listed in

the following table.

Remote Commands 5-11

Table 5-4. Reset State (Default Setting)

Parameter Reset Value

HP 8167A HP 8168D HP 8168E HP8168F

Wavelength 1310nm 1540nm 1540nm 1540nm

df 0GHz

Display Mode nm

Power minimum

Power/Attenuation Mode Power

Unit (Power)



Modulation Timing External

Modulation Status O

The minimum value is determined, individually for each instrument at calibration.

Example

OUTPUT 724;"*RST"

*SAV

Syntax

*SAV<wsp

location

1location5

Denition

The instrument setting is stored in RAM. You can store settings

in locations 1-5. The scope of the saved setting is identical with

the scope of the standard setting described in \*RST".

Example

OUTPUT 724;"*SAV 3"

*SRE

Syntax

*SRE<wsp

value

0value255

Denition

The service request enable command sets bits in the service

request enable register that enable the corresponding status

byte register bits.

The register is cleared:

At power-on

By sending a value of zero.

The register is not changed by the

5-12 Remote Commands

*RST

and

*CLS

commands.

BITS MNEMONICS BIT VALUE

7 Operation Status 128

6 Request Status 64

5 Event Status Byte 32

4 Message Available 16

3 Questionable Status 8

2 Not used 0

1 Not used 0

0 Not used 0

The Service Request Enable Register

Note

*SRE?

Example

*STB?

Syntax

Denition

Bit 6 cannot be masked.

The service request enable query returns the contents of the

service request enable register.

OUTPUT 724;"*SRE 48"

OUTPUT 724;"*SRE?"

ENTER 724; A$

*STB?

The read status byte query returns the contents of the status

byte register.

0contents255

Remote Commands 5-13

BITS MNEMONICS BIT VALUE

7 Operation Status 128

6 Request Service 64

5 Event Status Byte 32

4 Message Available 16

3 Questionable Status 8

2 Not used 0

1 Not used 0

0 Not used 0

The Status Byte Register

Example

*TST?

Syntax

Denition

OUTPUT 724;"*STB?"

ENTER 724; A$

*TST?

The self-test query commands the instrument to perform a

self-test and place the results of the test in the output queue.

Returned value: 0value65535. This value is the sum of

the results for the individual tests

5-14 Remote Commands

BITS MNEMONICS BIT VALUE



P1 Board 32768



P2 Board 16384

13 Battery Test 8192

6 Motor 3 (Opt. 003) 64

5 Motor 2 32

4 Motor 1 16

3 Laser Control Board 8

2 Analog to Digital Conv. 4

1 Hardware Interface 2

0 Calibration Data 1

The Self Test Results

So 16 would mean that Motor 1 had failed, 18 would mean that

Motor 1 had failed, and so had the hardware interface. A value

of zero indicates no errors.

If the self-test fails, the results are also put in the error queue.

It is recommended that you read self-test results from the error

queue. Explanations for the non-zero results of the self-test are

given in Appendix F.

Example

No further commands are allowed while the test is running.

The instrument is returned to the setting that was active at the

time the self-test query was processed.

The self-test does not require operator interaction beyond

sending the

*TST?

query.

OUTPUT 724;"*TST?"

ENTER 724; A$

Remote Commands 5-15

*WAI

Syntax

Denition

*WAI

The wait-to-continue command prevents the instrument from

executing any further commands, all pending operations are

completed. There is a delay of approximately 0.1 seconds

between the completion of the nal operation and the parsing

of the next command.

Example

OUTPUT 724;"*WAI"

:DISPlay Commands

:DISPlay:ENABle

Syntax

Description

:DISPlay:ENABle<wsp>OFFjONj0j1

This command enables or disables the front panel display.

Set the state to

OFFor0

to switch the display o, set the state

toONor1to switch the display on. The default is for the

display to be on.

:DISPlay:ENABle?

Syntax

Description

:DISPlay:ENABle?

The query returns the current state of the display.

A returned value of0indicates that the display is o. A

returned value of1indicates that the display is on.

Example

OUTPUT 724;":DISP:ENAB ON"

OUTPUT 724;":DISP:ENAB?"

ENTER 724;A$

5-16 Remote Commands

:LOCK Commands

:LOCK

Syntax

Description

:LOCK<wsp>OFFjONj0j1,<value

This command switches the lock o and on.

Set the state to

toONor1to switch the lock on. The laser is switched o

immediately when the instrument is locked.

value>is the four-gure password.

:LOCK?

Syntax

Description

:LOCK?

The query returns the current state of the lock.

A returned value of0indicates that the lock is o. A returned

value of1indicates that the lock is on.

Example

OUTPUT 724;":LOCK ON, 8168"

OUTPUT 724;":LOCK?"

ENTER 724;A$

:OUTPut Commands

OFFor0

to switch the lock o. Set the state

:OUTPut[:STATe]

Syntax

Description

:OUTPut[:STATe]<

This command switches the laser current o and on.

Laser light emerges only when the current is on. Set the state

OFFor0

or1to switch the laser current on. The default is for the laser

current to be o.

wsp>OFFjONj0j1

to switch the laser current o, set the state to

Remote Commands 5-17

:OUTPut[:STATe]?

Syntax

Description

:OUTPut[:STATe]?

The query returns the current state of the laser current.

A returned value of0indicates that the laser current is o. A

returned value of1indicates that the laser current is on.

Example

OUTPUT 724;":OUTP ON"

OUTPUT 724;":OUTP?"

ENTER 724;A$

[:SOURce] Commands

[:SOURce]:AM:INTernal:FREQuency

Syntax

Description

[

:SOURce]:AM:INTernal:FREQuency<wsp

value>j

MINjDEFjMAX

This command sets the frequency of the amplitude modulation

of the laser output.

The frequency can be set in the range 250Hz to 300kHz. You

can set to the minimum, default or maximum programmable

values by sending

MIN,DEF

,or

MAX

, respectively, instead of the

value.

The default units areHZ, though

alternatively be specied.

The resolution of the frequency is given in the table below:

5-18 Remote Commands

KHZ,MAHZ,GHZ,THZ

Range (Hz) Resolution (Hz)

250 ... 999 1

1 000 ... 9990 10

10 000 . . . 99 900 100

100 000 . . . 300 000 1000

can

[:SOURce]:AM:INTernal:FREQuency?

Syntax

Description

[

:SOURce]:AM:INTernal:FREQuency?[MINjDEFjMAX

This query returns the frequency of the amplitude modulation,

as a oating point number in Hertz. If you specify

MAX

with the query, it will return, respectively, the minimum,

default, or maximum modulation frequency.

Example

OUTPUT 724;":AM:INT:FREQ 40.4KHZ"

OUTPUT 724;":AM:STAT ON"

OUTPUT 724;":AM:INT:FREQ?"

ENTER 724;A$

[:SOURce]:AM:SOURce

Syntax

Description

[

:SOURce]:AM:SOURce<wsp>INTjINT1jINT2jEXTj0j1j2

This command chooses the type or source of the modulation of

the laser output.

Set the source to

set the source to

default is for internal modulation to be selected.

Modulation

Input

When external modulation is selected, the signal is modulated

according to the signal applied to the modulation input on the

front panel of the instrument. The maximum signal that can be

applied is 5Vpp, which results in 15% modulation of the optical

output.

INT,INT1or0

INT2or1

EXTor2

to select coherence control, or

to select external modulation. The

]

MIN,DEF

,or

to select internal modulation,

[:SOURce]:AM:SOURce?

Syntax

Description

[

:SOURce]:AM:SOURce?

The query returns the current state of modulation.

A returned value of0indicates that internal modulation is

selected. A returned value of1indicates that coherence control

is selected,2indicates that external modulation is selected.

Example

OUTPUT 724;":AM:SOUR ON"

OUTPUT 724;":AM:SOUR?"

ENTER 724;A$

Remote Commands 5-19

[:SOURce]:AM:STATe

Syntax

Description

[

:SOURce]:AM:STATe<wsp>OFFjONj0j1

This command enables and disables amplitude modulation of the

laser output.

Set the state to

ONor1

to enable modulation. The default is for the modulation

OFFor0

to disable modulation, set the state to

to be disabled.

Modulation

Output

When the internal modulation is selected, the Modulation

Output on the front panel outputs a version of the modulating

signal that has the same frequency and phase as the modulating

signal, but has a xed, TTL-level amplitude.You can use this to

synchronize your external measuring equipment to the tunable

laser source.

To allow for your possible synchronization requirements,

there are two ways in which the signal can be output. Either

the signal is combined with the laser-ready signal, so that

the output is kept low when there is no optical signal being

output (for example, while the laser is settling after a change

of wavelength). Or the modulation signal is output all the

time. This is set by the

:SOURCE:MODOUT

command (see

\[:SOURCE]:MODOUT").

[:SOURce]:AM:STATe?

Syntax

Description

[

:SOURce]:AM:STATe?

The query returns the current state of modulation.

A returned value of0indicates that modulation is disabled. A

returned value of1indicates that modulation is enabled.

Example

OUTPUT 724;":AM:STAT ON"

OUTPUT 724;":AM:STAT?"

ENTER 724;A$

5-20 Remote Commands

[:SOURCE]:MODOUT

Note

Syntax

Description

This command does not conrm to the SCPI standard.

[

:SOURCE]:MODOUT FRQjFRQRDYj0j1

This command sets the modulation output. The two possible

values are

FRQor0

and

FRQRDYor1

the laser-ready signal, so that the output is kept low when

there is no optical signal being output (for example

laser is settling after a change of wavelength).

[:SOURCE]:MODOUT?

Note

Syntax

Description

This command does not conrm to the SCPI standard.

[

:SOURCE]:MODOUT?

This queries the mode of the modulation output. The two

possible values are

, where the modulation signal is output all the time,

, where the modulation signal is combined with

, while the

, where the modulation signal is output all the time, and

, where the modulation signal is combined with the

laser-ready signal, so that the output is kept low when there

is no optical signal being output (for example, while the laser

is settling after a change of wavelength).

Remote Commands 5-21

[:SOURce]:POWer:ATTenuation

Attenuator

Syntax

Description

[

:SOURce]:POWer:ATTenuation<wsp

value>j

MINjDEFjMAX

This command sets the level of attenuation of

an inbuilt optional attenuator, if this is installed.

The specied range for the attenuation is

0.00dB to 40.00dB.You can set to the minimum,

default or maximum programmable values by

sending

MIN,DEF

,or

MAX

, respectively, instead

of the value.

The resolution of the attenuation is specied

to be 0.1dB. The actual resolution of the

attenuator is better than this (typically 0.04dB).

To allow you access to this resolution, you can

specify the attenuation to two decimal places

with the HP-IB command.

You need to be in the Attenuation Mode (see

\[:SOURce]:POWer:ATTenuation:AUTO")

for this value to have an aect. The

output power is a combination of

this value and the laser output power (see

\[:SOURce]:POWer[:LEVel][:IMMediate][:AMPlitude]").

In this respect, this command does not conrm

to the SCPI standard. The SCPI standard

requires that entering an explicit value for the

attenuation switches the attenuation mode

OFF

The default units areDB.

[:SOURce]:POWer:ATTenuation?

Attenuator

Syntax

Description

[

:SOURce]:POWer:ATTenuation?[MINjDEFjMAX

This query returns the attenuation level of the

optional attenuator if this has been installed.

5-22 Remote Commands

]

The value returned is applies

only to the attenuation mode (see

\[:SOURce]:POWer:ATTenuation:AUTO?").

If you specify

it will return, respectively, the minimum,

default, or maximum amplitude level.

Example

OUTPUT 724;":POW:ATT:AUTO OFF"

OUTPUT 724;":POW 200UW OUTPUT

724;":POW:ATT 22.32DB"

OUTPUT 724;":POW:ATT?" ENTER 724;A$

[:SOURce]:POWer:ATTenuation:AUTO

Attenuator

Syntax

[

:SOURce]:POWer:ATTenuation:AUTO<wsp

OFFjONj0j1

Description

This command selects Power or Attenuation

Mode.InPower Mode, you specify the output

power. In Attenuation Mode, you must

specify both the laser output power, and the

attenuation level.

UseONor1to select Power Mode.

Use

OFFor0

to select Attenuation Mode

MIN,DEF

,or

MAX

with the query,

[:SOURce]:POWer:ATTenuation:AUTO?

Attenuator

Syntax

Description

[

:SOURce]:POWer:ATTenuation:AUTO?

This query returns whether the instrument is in

Power Mode, or Attenuation Mode.

indicates Power Mode.

indicates Attenuation Mode

Remote Commands 5-23

[:SOURce]:POWer:ATTenuation:DARK

Note

Attenuator

This command does not conrm to the SCPI standard.

Syntax

Description

[

:SOURce]:POWer:ATTenuation:DARK OFFjONj0j1

UseONor1to set the attenuator to the \dark"

position. This blocks all light from the laser.You

can use this as an alternative to disabling the

laser, the advantage of doing this is that you

avoid the laser rise time.

This command is available in Attenuation Mode

Only.

[:SOURce]:POWer:ATTenuation:DARK?

Note

Attenuator

This command does not conrm to the SCPI standard.

Syntax

Description

[

:SOURce]:POWer:ATTenuation:DARK? 0j1

This query returns whether the attenuator is in

the \dark" position (where all light is blocked

by the laser) or not. If the attenuator is in the

dark position,1is returned.

Example

5-24 Remote Commands

OUTPUT 724;":POW:ATT:DARK ON"

OUTPUT 724;":POW:ATT:DARK?" ENTER 724;A$

[:SOURce]:POWer[:LEVel][:IMMediate][:AMPlitude]

Syntax

Description

Attenuator

Note

[

:SOURce]:POWer[:LEVel][:IMMediate][:AMPlitude]<

value>j

MINjDEFjMAX

wsp

This command sets the power of the laser output.

The specied range for the amplitude is -10dBm to -4dBm,

or 100W to 398W.You can set to the minimum, default or

maximum programmable values by sending

MIN,DEF

,or

MAX

respectively, instead of the value.

If you have the optional attenuator installed, the range is

-50dBm to -5.5dBm, or 10nW to 300W.

If you are using the Attenuation Mode (see

\[:SOURce]:POWer:ATTenuation:AUTO"), then this

value sets the laser output power, which is not the same as the

output power. The output power is a combination of this value

and the attenuation (see \[:SOURce]:POWer:ATTenuation").

The values for the output power that you set in the Power

Mode, and the laser output power that you set in the

Attenuation Mode, are stored and used independently.

The instrument may not be able to output a signal

with the maximum programmable power, it will

output a signal with the maximum power. Use the

[:SOURce]:POWer[:LEVel][:IMMediate][:AMPlitude]? query to

nd out the power being output.

The default units are

by the [

:SOURce]:POWer:UNIT

DBM

,orW, depending on the unit selected

command. Independently of the

chosen default unit, you can also specify the unit to be used as

DBM,DBMW,PW,NW,UW,MWorW

[:SOURce]:POWer[:LEVel][:IMMediate][:AMPlitude]?

Syntax

Description

[

:SOURce]:POWer[:LEVel][:IMMediate][:AMPlitude]?

[

MINjDEFjMAX

]

This query returns the amplitude level of the output power. The

value returned is the actual amplitude that is output, which

Remote Commands 5-25

may be dierent from the value set for the output. If these two

gures are not the same, it is indicated in the STATus:OPERation

Attenuator

If you have the optional attenuator installed, the value returned

for the power is dependent on whether you are in power or

attenuation mode (see \[:SOURce]:POWer:ATTenuation:AUTO?").

If you are in power mode, the value returned is the

output power. If you are in attenuation mode, the value

returned is the laser output power, and you must also use

the attenuation value to calculate the output power (see

\[:SOURce]:POWer:ATTenuation?").

If you specify

MIN,DEF

,or

MAX

with the query, it will return,

respectively, the minimum, default, or maximum amplitude

level.

Example

OUTPUT 724;":POW:UNIT DBM"

OUTPUT 724;":POW? MAX"

ENTER 724;A$ OUTPUT 724;":POW ",A$

[:SOURce]:POWer:UNIT

Syntax

Description

[

:SOURce]:POWer:UNIT<wsp>DBMjDBMWjWatt

This command sets the power units. Set the units to dBm by

sending

DBMorDBMW

. Set the units to watts by sendingW. The

default units are dBm.

[:SOURce]:POWer:UNIT?

Syntax

Description

[

:SOURce]:POWer:UNIT?

The query returns the units currently being used. The response

is either0for dBm or dBmW,or2for Watts.

Example

OUTPUT 724;":POW:UNIT DBM"

OUTPUT 724;":POW:UNIT?"

ENTER 724;A$

5-26 Remote Commands

[:SOURce]:WAVElength[:CWj:FIXED]

Syntax

Description

[

:SOURce]:WAVElength[:CWj:FIXED]<

value>j

MINjDEFjMAX

wsp

This command sets the absolute wavelength of the output. The

default units for the wavelength are meters.

The specied range for the wavelength is given in the table

below.

Table 5-5. Specied Wavelength range

Min Max Default

HP 8167A

1280nm 1330nm 1310nm

HP 8168D

1490nm 1565nm 1540nm

HP 8168E

1475nm 1575nm 1540nm

HP 8168F

1450nm 1590nm 1540nm

The programmable range is larger than this. The programmable

range is set individually for each instrument when it is

calibrated during production. You can set the wavelength to the

maximum, default or minimum wavelength by sending

MAX

, respectively, instead of the value.

MIN,DEF

The default units areM, thoughPM,NM,UM,MMcan alternatively

be specied.

[:SOURce]:WAVElength[:CWj:FIXED]?

Syntax

Description

[

:SOURce]:WAVElength[:CWj:FIXED]?[MINjDEFjMAX

The query returns the current wavelength in meters.If

you specify

MIN,DEF

,or

MAX

respectively, the minimum, default, or maximum wavelength.

]

with the query, it will return,

Remote Commands 5-27

Example

OUTPUT 724;":WAVE:REF:STAT OFF"

OUTPUT 724;":WAVE 1542E-9"

OUTPUT 724;":WAVE?"

ENTER 724;A$

[:SOURce]:WAVElength:REFerence?

Syntax

Description

Example

[

:SOURce]:WAVElength:REFerence?

The query returns the reference wavelength (

OUTPUT 724;":WAVE:REF?"

0) in meters.

ENTER 724;A$

[:SOURce]:WAVElength:REFerence:DISPlay

Syntax

Description

Example

[

:SOURce]:WAVElength:REFerence:DISPlay

This command sets the reference wavelength to the value of the

output wavelength (!



OUTPUT 724;":WAVE:REF:DISP"

[:SOURce]:WAVElength:FREQuency

Syntax

Description

[

:SOURce]:WAVElength:FREQuency<wsp

value

This command sets the frequency dierence used to calculate

a relative wavelength. The output wavelength is made up

of the reference wavelength and this frequency dierence.

The default units for the frequency are Hertz. The output

wavelength () is set from the base wavelength (

0) and the

frequency oset (df). The formula for calculating the output

wavelength is:



)df+

(



where c is the speed of light in a vacuum (2.9982108ms-1).

[:SOURce]:WAVElength:FREQuency?

Syntax

[

:SOURce]:WAVElength:FREQuency?

5-28 Remote Commands

Description

The query returns the frequency dierence in Hertz.

Example

:STATus Commands

Each node of the status circuitry has ve registers:

A condition register (CONDition), which contains the current status

A positive transition register (PTRansition), which, when enabled, puts a 1

into the event register, when the corresponding bit in the condition register

goes from 0 to 1.

The power-up condition for this register is for all the bits to be disabled.

A negative transition register (NTRansition), which, when enabled, puts a 1

into the event register, when the corresponding bit in the condition register

goes from 1 to 0.

The power-up condition for this register is for all the bits to be disabled.

The event register (EVENt), which contains the output from the transition

registers. The contents of this register are cleared when it is read.

OUTPUT 724;":WAVE:FREQ 11E9"

OUTPUT 724;":WAVE:FREQ?"

ENTER 724;A$

.This

The enable register (ENABle), which enables changes in the event register to

aect the Status Byte.

The status registers for the tunable laser source are organized as shown:

Remote Commands 5-29

Figure 5-2. The Status Registers

The OPERation branch of the status registers indicates things that can happen

during normal operation. The QUEStionable branch indicates error conditions.

:STATus:OPERation:CONDition?

Syntax

Description

Example

5-30 Remote Commands

:STATus:OPERation:CONDition?

This query reads the contents of the OPERation:CONDition

Bit 8, which is 1 when the output power that you set exceeds

what the laser is capable of producing.

Bit 9, which is 1 while the instrument is performing its

power-up initialization.

OUTPUT 724;":STAT:OPER:COND?"

ENTER 724;A$

Agilent 8168F Users Guide

Specifications and Main Features

Frequently Asked Questions

User Manual