Agilent Technologies 81950A User manual

Agilent Technologies
Agilent 81950A
Compact Tunable Laser Source module
User’s Guide

Notices
© Agilent Technologies, Inc. 2012
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Manual Part Number
81950-90B01
Edition
Second edition, June 2012
Agilent Technologies Deutschland GmbH
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71034 Böblingen, Germany
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Safety Notices
CAUTION
A CAUTION notice denotes a
hazard. It calls attention to an
operating procedure, practice, or
the like that, if not correctly
performed or adhered to, could
result in damage to the product
or loss of important data. Do not
proceed beyond a CAUTION
notice until the indicated
conditions are fully understood
and met.
WARNING
A WARNING notice denotes a
hazard. It calls attention to an
operating procedure, practice,
or the like that, if not correctly
performed or adhered to, could
result in personal injury or
death. Do not proceed beyond a
WARNING notice until the
indicated conditions are fully
understood and met.

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In This Guide...
Chapter 1, “Getting Started"
This chapter contains an introductory description of the modules and aims
to make the modules familiar to you.
Chapter 2, “Accessories"
This chapter contains details of the various modules and options available.
Chapter 3, “Operating Instructions"
This chapter provides a general description of the specific features of the
81950A compact tunable laser module.
Chapter 4, “Programming Instructions"
This chapter describes the SCPI Commands for use of 81950A compact
tunable laser modules and N7711A, N7714A single and 4-port Tunable
Laser System Sources.
Chapter 5, “Specifications"
This chapter contains the specifications of the 81950A module.
Chapter 6, “Cleaning Information"
This chapter provides the cleaning instructions
Chapter 7, “Index"

Agilent 81950A Compact TLS module,First Edition 5
Table of Contents
Getting Started 11
Safety Considerations 12
Safety Symbols 12
Initial Inspection 13
Line Power Requirements 13
Operating Environment 13
Input/Output Signals 14
Storage and Shipment 14
Initial Safety Information for Tunable Laser Modules 15
Laser Safety Labels 16
Laser class 1M label 16
Introduction 17
What is a Tunable Laser Source? 17
Installation 17
Front Panels 17
Front Panel Controls and Indicators 18
Typical Use Models 19
Optical Output 21
Polarization Maintaining Fiber 21
Angled and Straight Contact Connectors 22
Signal Input and Output 23
Accessories 25
Modules and Options 26
Modules 27
Options 27
Connector Interfaces 28
User’s Guides 29

6Agilent 81950A Compact TLS module, First Edition
Operating Instructions 31
Operation 33
Parameters 33
Output Frequency 33
Limitations 33
Changing the Grid (f0, s) 34
Operation Modes 34
Switching Modes 34
Preset Values 35
Differences to Other Tunable Laser Source Modules 35
The Graphical User Interface 36
Differences among 8164A/B, 8163A/B and 8166A/B 36
Soft Lock 36
How to Set a Parameter 37
How to Set the Power 39
How to Switch Operation Mode 40
How to Set the Wavelength or Frequency 43
How to Switch On the Laser 44
How to set Frequency Parameters in Grid Mode 45
How to Check the Output Frequency or Wavelength 46
How to Modulate a Signal 47
The User Interface 49
The Module's Front Panel 49
Programming Instructions 51
Summary 52
Detailed Description 54
The OUTPut sub tree 54
The SOURce:CHANnel:POWer sub tree 56
The SOURce:CHANnel:WAVelength sub tree 59
The SOURce:CHANnel:FREQuency sub tree 61
The SOURce:CHANnel:MODUIation sub tree 67
Error Messages 71
Status Bits 72

Agilent 81950A Compact TLS module,First Edition 7
Differences among 81950A, N7711A and N7714A 73
81950A Only 73
N771A, N7714A Only 73
Specifications 75
Definition of Terms 77
Absolute wavelength (frequency) accuracy 78
External analog modulation - modulation depth 78
Linewidth 78
Maximum output power 79
Operating temperature and humidity 79
Output isolation 79
Polarization extinction ratio 80
Power flatness versus wavelength 81
Power repeatability 81
Power stability 82
Relative intensity noise (RIN) 82
Relative wavelength (frequency) accuracy 83
Return loss 83
SBS suppression - effective linewidth 84
Side-mode suppression ratio 84
Signal to source spontaneous emission ratio 84
Tuning time 85
Wavelength range 85
Wavelength (frequency) repeatability 86
Wavelength resolution 86
Wavelength (frequency) stability 86
Compact Tunable Laser Module Specifications 87
Agilent 81950A Compact Tunable Laser Source 88
Specifications 89
Cleaning Information 91
Cleaning Instructions 92
Safety Precautions 92
Why is it important to clean optical devices ? 93
What do I need for proper cleaning? 94

8Agilent 81950A Compact TLS module, First Edition
Preserving Connectors 98
Cleaning Instrument Housings 98
Which Cleaning Procedure should I use? 99
How to clean connectors 100
How to clean connector interfaces 102
How to clean bare fiber adapters 103
How to clean instruments with a fixed connector interface 104
Additional Cleaning Information 105
Other Cleaning Hints 106
Index 107

Agilent 81950A Compact TLS module,First Edition 9

10 Agilent 81950A Compact TLS module, First Edition

Agilent 81950A Compact TLS module, First Edition 11
1
Getting Started
This chapter provides a general description of Agilent 81950A Compact
TLS module.
Safety Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Safety Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Initial Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Line Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Operating Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Input/Output Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Storage and Shipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Initial Safety Information for Tunable Laser Modules . . . 15
Laser Safety Labels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
What is a Tunable Laser Source? . . . . . . . . . . . . . . . . . . . . . . . . . 17
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Front Panels. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Front Panel Controls and Indicators . . . . . . . . . . . . . . . . . . . . . . 18
Typical Use Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Optical Output. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Polarization Maintaining Fiber . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Angled and Straight Contact Connectors . . . . . . . . . . . . . . . . . . 22
Signal Input and Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Getting Started Safety Considerations
12 Agilent 81950A Compact TLS module, First Edition
Safety Considerations
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 specific warnings elsewhere in this
manual violates safety standards of design, manufacture, and intended
use of the instrument. Agilent Technologies Inc. assumes no liability for
the customer’s failure to comply with these requirements.
Before operation, review the instrument and manual, including the red
safety page, for safety markings and instructions. You must follow these to
ensure safe operation and to maintain the instrument in safe condition.
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.
Hazardous laser radiation.
Invisible laser radiation.
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.
CAUTIONWARNING

Safety Considerations Getting Started
Agilent 81950A Compact TLS module, First Edition 13
Initial Inspection
Inspect the shipping container for damage. If there is damage to the
container or cushioning, keep them until you have checked the contents of
the shipment for completeness and verified the instrument both
mechanically and electrically.
The Performance Tests give procedures for checking the operation of the
instrument. If the contents are incomplete, mechanical damage or defect
is apparent, or if an instrument does not pass the operator’s checks, notify
the nearest Agilent Technologies Sales/Service Office.
Line Power Requirements
The Agilent 81950A Compact Tunable Laser Source modules operate when
installed in Agilent 8163A/B Lightwave Multimeters, Agilent 8164A/B
Lightwave Measurement Systems, and Agilent 8166A/B Lightwave
Multichannel Systems.
Operating Environment
The safety information in your mainframe’s User’s Guide summarizes the
operating ranges for the Agilent 81950A Compact Tunable Laser Source
modules. In order for these modules to meet specifications, the operating
environment must be within the limits specified for your mainframe.
To avoid hazardous electrical shock, do not perform electrical
tests when there are signs of shipping damage to any portion of
the outer enclosure (covers, panels, etc.).
CAUTIONWARNING
You MUST return instruments with malfunctioning laser modules
to an Agilent Technologies Sales/Service Center for repair and
calibration.
CAUTIONWARNING

Getting Started Safety Considerations
14 Agilent 81950A Compact TLS module, First Edition
Input/Output Signals
Storage and Shipment
An Agilent 81950A Compact Tunable Laser Source module can be stored or
shipped at temperatures between - 40°C and + 70°C.
Protect the module from temperature extremes that may cause
condensation within it.
There is one BNC input connector on the front panel of an Agilent
81950A Compact Tunable Laser Source module.
To prevent the BNC interface from damage, do not exceed the
voltage limit of +- 5V when applying external voltage.
CAUTION

Initial Safety Information for Tunable Laser Modules Getting Started
Agilent 81950A Compact TLS module, First Edition 15
Initial Safety Information for
Tunable Laser Modules
The laser sources specified by this user guide are classified according to
IEC 60825-1 (2007) Laser Notice No. 50 dated 2007-June-24.
The laser sources comply with 21 CFR 1040.10 except for deviations
pursuant to Laser Notice No. 50 dated 2001-July-26:
Agilent 81950A
Option 210
Agilent 81950A
Option 201
Laser Type ECL-Laser
InGaAsP
ECL-Laser
InGaAsP
Wavelength range 1527nm-1566nm 1570nm-1609nm
Max. CW output power* 50 mW 50 mW
Beam waist diameter 9 μm 9 μm
Numerical aperture 0.1 0.1
Laser Class according to
IEC 60825-1 (2001)- Intl.
1M 1M
Max. permissible CW output
power**
163 mW 163 mW
* Max. CW output power is defined as the highest possible optical power that
the laser source can produce at its output connector.
** Max. permissible CW output power is the highest optical power that is
permitted within the appropriate laser class.

Getting Started Laser Safety Labels
16 Agilent 81950A Compact TLS module, First Edition
Laser Safety Labels
Laser class 1M label
A sheet of laser safety labels is included with the laser module as required.
In order to meet the requirements of IEC 60825-1 we recommend that you
stick the laser safety labels, in your language, onto a suitable location on
the outside of the instrument where they are clearly visible to anyone
using the instrument.
Figure 1 Class 1M Safety Label - 81950A
Please pay attention to the following laser safety warning:
Under no circumstances look into the end of an optical cable
attached to the optical output when the device is operational. The
laser radiation can seriously damage your eyesight.
Do not enable the laser when there is no fiber attached to the
optical output connector.
The laser is enabled by pressing the ’active’ button close to the
optical output connector on the front panel of the module. The
laser is on when the green LED on the front panel of the instrument
is lit.
The use of optical instruments with this product will increase eye
hazard.
The laser module has a built-in safety circuitry which will disable
the optical output in the case of a fault condition
Refer servicing only to qualified and authorized personnel.
CAUTIONWARNING

Introduction Getting Started
Agilent 81950A Compact TLS module, First Edition 17
Introduction
What is a Tunable Laser Source?
A Tunable Laser Source (TLS) is a laser source for which the wavelength
can be varied through a specified range. The Agilent Technologies range of
TLS modules also allow you to set the output power, and to choose
between continuous wave or modulated power.
The Agilent Technologies range of compact TLS modules are flexible
stimulus modules suitable for applications such as the testing of optical
amplifiers, DWDM components, and complete DWDM systems.
Installation
The Agilent 81950A Compact TLS module is a front-loadable module.
For a description of how to install your module, refer to “How to Fit and
Remove Modules” in the Installation and Maintenance chapter of your
mainframe’s User’s Guide.
Front Panels
Figure 2 Agilent 81950A Compact Tunable Laser Module
Angled Contact Connector
Agilent 81950A with
Straight Contact Connector
Agilent 81950A with

Getting Started Introduction
18 Agilent 81950A Compact TLS module, First Edition
Front Panel Controls and Indicators
Switch the laser source on or off using the switch on its front panel, using
the [State] parameter in the instrument’s Graphical User Interface, or
remotely using SCPI commands. When the Active LED is lit the source is
emitting radiation. When the Active LED is not lit the source is not emitting
radiation.

Typical Use Models Getting Started
Agilent 81950A Compact TLS module, First Edition 19
Typical Use Models
The Agilent 81950A Compact TLS module provides high output power up
to +15.5 dBm.
This module covers a total wavelength range of 40 nm, either:
•In the C-band
with the 81950A Option 210, or
•In the L-band
with the 81950A Option 201.
Their compact single-slot format makes them a flexible and cost-effective
stimulus for single channel and multichannel DWDM applications
Device Characterization at high power levels
The high optical output power of the Agilent 81950A Compact TLS module
improves the testing of all types of optical amplifiers and other active
components as well as broadband passive optical components. It helps
overcome losses in test setups or in the device under test itself. Thus,
engineers can test optical amplifiers such as EDFAs, Raman amplifiers,
SOAs and EDWAs to their limits. This tunable laser provides the high
power levels required to help speed the development of innovative devices
by enabling the test and measurement of nonlinear effects.
Low linewidth source for complex modulation formats
The low linewidth of the Agilent 81950A Compact TLS module makes this
module an ideal light source for transmission systems with (D)QPSK and
higher order modulation formats and and as local oscillator for coherent
receivers. The fine tuning capability allows to precisely set the
intermediate frequency in the coherent receiver.
SBS suppression feature enables high launch power
The SBS Suppression feature avoids the reflection of light induced by
Stimulated Brillouin Scattering (SBS). It enables the launch of the high
optical output power into long fibers without intensity modulation to avoid
impairment in time-domain measurements.

Getting Started Typical Use Models
20 Agilent 81950A Compact TLS module, First Edition
Specifications:
For further details on specifications, see the “Specifications” on page 75.