Agilent Technologies 81663A User manual

Agilent Technologies
Agilent 81663A
DFB Laser Source
Module
User’s Guide

Notices
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Safety Notices
CAUTION
A CAUTION notice denotes a haz-
ard. It calls attention to an operat-
ing 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 per-
formed or adhered to, could result
in personal injury or death. Do not
proceed beyond a WARNING
notice until the indicated condi-
tions are fully understood and met.
Manual Part Number
81661-90A15
Edition
Eighth Edition, May 2010
Seventh Edition, December 2007
Sixth Edition, June 2005
Seventh Edition, February 2002
Fourth Edition, August 2001
Third Edition, January 2001
Second Edition, October 2000
First Edition, June 2000
Agilent Technologies Deutschland GmbH
Herrenberger Str. 130
71034 Böblingen, Germany.

Agilent DFB Laser Source Module User’s Guide 3
Agilent Technologies Sales and Service Offices
For more information about Agilent Technologies test and
measurement products, applications, services, and for a current
sales office listing, visit our web site:
http://www.agilent.com/comms/lightwave
You can also contact one of the following centers and ask for a
test and measurement sales representative.
United States: (tel) 800 829 4444
(fax) 800 829 4433
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Other Asia Pacific
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Email: [e-mail]

4 Agilent DFB Laser Source Module User’s Guide

Agilent DFB Laser Source Module User’s Guide 5
Ta b l e o f C o n t e n t s
Agilent Technologies Sales and Service Offices 3
1 Getting Started with DFB Laser Sources
Safety Considerations 8
Safety Symbols 8
Initial Inspection 8
Line Power Requirements 9
Operating Environment 9
Storage and Shipment 9
Environmental Information 9
Initial Safety Information for the DFB Laser Source Module 10
Laser Safety Labels 10
What is a DFB Laser Source Module? 11
A Description of the Front Panel 11
Optical Output 11
Operation Note 13
Maintaining Wavelength Accuracy Below Maximum Power 13
2Accessories
Recommended Connector Interfaces 16
Wavelength Options 16
3 Performance Tests
Equipment Required 18
Te st R e co r d 1 8
Tes t F ai l u re 1 8
Instrument Specification 18
Performance Test Instructions 19
All Wavelength Tests 19
Wavelength Repeatability Test 19

6 Agilent DFB Laser Source Module User’s Guide
Wavelength Stability Test 20
Te st R e co r d s 2 1
4 Cleaning Information
Safety Precautions 26
Why is it important to clean optical devices? 27
What do I need for proper cleaning? 28
Standard Cleaning Equipment 28
Additional Cleaning Equipment 31
Preserving Connectors 33
Cleaning Instrument Housings 34
Which Cleaning Procedure should I use ? 35
How to clean connectors 36
How to clean connector adapters 38
How to clean connector interfaces 39
How to clean bare fiber adapters 40
How to clean lenses 41
How to clean instruments with a fixed connector interface 42
How to clean instruments with an optical glass plate 43
How to clean instruments with a physical contact interface 44
How to clean instruments with a recessed lens interface 45
How to clean optical devices which are sensitive to mechanical stress and
pressure 46
How to clean metal filters or attenuator gratings 47
Additional Cleaning Information 48
How to clean bare fiber ends 48
How to clean large area lenses and mirrors 48
Other Cleaning Hints 51
5 Specifications
Definition of Terms 54
DFB Source Module Specifications 57
Supplementary Performance Characteristics 57

7
Agilent Technologies
Agilent 81663A DFB Laser Source Module User’s Guide
1
Getting Started with DFB Laser Sources
This chapter introduces the features of the Agilent 81663A DFB
Laser Source Module.

8 Agilent DFB Laser Source Module User’s Guide
1
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 assumes no liability for the
customer’s failure to comply with these requirements.
Before operation, review the instrument and manual, including
the 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.
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.
WARNING
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.
WARNING
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.).

1
Agilent DFB Laser Source Module User’s Guide 9
Line Power Requirements
The Agilent 81663A DFB Laser Source Module operates when
installed in the Agilent 8163A/B Lightwave Multimeter,
Agilent 8164A/B Lightwave Measurement System, or
Agilent 8166A/B Lightwave Multichannel System.
Operating Environment
The safety information in the Agilent 8163A/B Lightwave
Multimeter, Agilent 8164A/B Lightwave Measurement System,
and Agilent 8166A/B Lightwave Multichannel System User’s
Guide summarizes the operating ranges for the Agilent 81663A
DFB Laser Source Module. In order for this module to meet
specifications, the operating environment must be within the
limits specified for the mainframe.
Storage and Shipment
The 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.
Environmental Information
This product complies with the WEEE Directive (2002/96/EC)
marking requirements. The affixed label indicates that you must
not discard this electrical/ electronic product in domestic
household waste.
Product Category: With reference to the equipment types in the
WEEE Directive Annex I, this product is classed as a
"Monitoring and Control instrumentation" product.
Do not dispose in domestic household waste.
To return unwanted products, contact your local Agilent office,
or see www.agilent.com/environment/product/ for more
information
WARNING
You MUST return instruments with malfunctioning laser modules
to an Agilent Technologies Service Center for repair and
calibration.

10 Agilent DFB Laser Source Module User’s Guide
1
Initial Safety Information for the DFB Laser Source Module
The laser sources specified by this user guide are classified
according to IEC 60825-1 (2001)
The laser sources comply with 21 CFR 1040.10 except for
deviations pursuant to Laser Notice No. 50, dated 2001-July-26.
Laser Safety Labels
Laser class 1M label
Figure 1 Class 1M Safety Label - Agilent 81663A
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.
Tab l e 1 DFB Laser Source Module Safety Information
Agilent 81663A
Laser type CW DFB Laser
with built-in isolator
Wavelength range 1300 to 1650 nm
see display
Max. CW output power* <28 mW
Beam waist diameter 9 µm
Numerical aperture 0.1
Laser Class according to IEC 60825-1 (2001)- International 1M
Max. permissible CW output power 163 mW
* Max. CW output power is defined as the highest possible optical power that the laser
source can produce at its output connector

1
Agilent DFB Laser Source Module User’s Guide 11
What is a DFB Laser Source Module?
A distributed feedback (DFB) laser is a highly-coherent laser
source that emits radiation in a narrow spectral width. The
Agilent Technologies DFB laser source module may be tuned
within a specific wavelength range, the current wavelength is
displayed on the user interface of your mainframe. The center
wavelength your module supports is displayed on the front
panel, see Figure 2.
A Description of the Front Panel
Figure 2 Front Panel of DFB Laser Source Module
To insert the module into your mainframe see your mainframe’s
User’s Guide.
How to Enable/Disable Laser Output
If the laser is on, the green LED on the front panel of the module
is lit. If the laser is off, green LED on the front panel of the
module is unlit. You can switch the module by pressing the
Active button on the front panel of the module.
Optical Output
Polarization Maintaining Fiber
The Agilent 81663A DFB Laser Source module is equipped with
a polarization maintaining fiber (PMF) as standard, the PMF is
aligned to maintain the state of polarization.
1550.12 nm

12 Agilent DFB Laser Source Module User’s Guide
1
The fiber is of Panda type, with TE mode in the slow axis in line
with the connector key. A well defined state of polarization
ensures constant measurement conditions.
Figure 3 PMF Output Connector
Angled Contact Connectors
The Agilent 81663A DFB Laser Source module is equipped with
an angled contact optical output connector as standard.
Angled contact connector helps you to control return loss. With
angled fiber endfaces, reflected light tends to reflect into the
cladding, reducing the amount of light that reflects back to the
source.
Figure 4 Angled Contact Connector Symbols
Figure 4 shows the symbol that tells you the contact connector
of your tunable laser module is angled. The angled contact
connector symbol for an optical output equipped with a PMF is
colored green.
Ε
Η
Slow Axis (Polarization Axis)
Connector Key
Fiber Cladding
Fiber Core
(9-µm Diameter)
Stress Rods
Not to Scale
CAUTION
If the contact connector on your instrument is angled, you can only
use cables with angled connectors with the instrument.
CAUTION
Angled Contact
Connector Symbol
(with PMF)

1
Agilent DFB Laser Source Module User’s Guide 13
Operation Note
Maintaining Wavelength Accuracy Below Maximum Power
The wavelength accuracy of your DFB Laser Source module is
optimized when you set power to the maximum available for
your module. As you reduce power, the drive current through
the laser diode changes; this can mean that the actual output
wavelength may differ from the wavelength displayed on the
user interface of your mainframe.
To ensure wavelength accuracy at less than maximum power
you should perform the steps listed below. You will need to use
a wavelength meter, we recommend the Agilent 86120C
Multi-Wavelength Meter.
1Set up your equipment as displayed in Figure 5.
Figure 5 Wavelength Accuracy Setup
2On the user interface of your Agilent 8163A/B Lightwave
Multimeter, move to the DFB source module channel and
perform the following steps:
aMove to [P], and press Enter.
bSet the power value to the maximum power for the
module. The maximum power for the 81663A is 13 dBm.
Since the maximum displayed power of the 86120C is
10 dBm, we recommend you use a power splitter or
attenuator between the source and the wavelength meter.
cMove to [λ], and press Enter.
dSet the wavelength to the value you require.
eEnable the laser by pressing the button on the front panel
of the module.
3Allow your wavelength meter to settle to a stable wavelength
value. Check the displayed value against the value displayed
on the user interface of your 8163A/B Lightwave Multimeter.
8163A/B Wavelength Meter
DFB
Source

14 Agilent DFB Laser Source Module User’s Guide
1
4On the user interface of your 8163A/B Lightwave Multimeter,
perform the following steps:
aMove to [P], and press Enter.
bReduce the power for the module.
5Allow your wavelength meter to settle to a stable wavelength
value. If the displayed value is not accurate enough for your
application, on the user interface of your 8163A/B Lightwave
Multimeter, perform the following steps:
aMove to [λ], and press Enter.
bAdjust the wavelength value until the wavelength meter
displays the wavelength you require. Allow time for the
wavelength meter to settle.
NOTE
The DFB Laser Source channel will display a wavelength value that differs
from the value displayed by the wavelength meter. The wavelength meter
displays the correct value.

15
Agilent Technologies
Agilent 81663A DFB Laser Source Module User’s Guide
2
Accessories
The Agilent 81663A DFB Laser Source Module is available in
various configurations for the best possible match to the most
common applications.
This chapter provides information on the available options and
accessories.

16 Agilent DFB Laser Source Module User’s Guide
2
Recommended Connector Interfaces
Figure 6 Recommended Connector Interfaces
Wavelength Options
Agilent 8163A/B
Lightwave Multimeter
12
Connector
Interface
DFB Source
Module
DFB Laser Source
Module
81663A
Connector Interfaces
81000HI E-2000
81000KI SP/APC
81000NI FC/APC
81000SI DIN4108
Agilent 81663A
Option Number
Center Wavelength
[nm]
#131 1310
#149 1490
#151 1510
#155 1550
#162 1625

17
Agilent Technologies
Agilent 81663A DFB Laser Source Module User’s Guide
3
Performance Tests
The procedures in this section test the optical performance of
the instrument. The complete specifications to which the
Agilent 81663A DFB Laser Source Module is tested are given in
“Specifications” on page 53. All tests can be performed without
access to the interior of the instrument. The performance tests
refer specifically to tests carried out with APC connectors.

18 Agilent DFB Laser Source Module User’s Guide
3
Equipment Required
Equipment required for the performance test is listed below.
Te s t R e c o rd
Results of the performance test may be noted in the Test Record
provided at the end of the Test Procedures. The Test Record can
also be used as a permanent record and may be reproduced
without written permission from Agilent Technologies.
Test Failure
If the Agilent 81663A DFB Laser Source Module fails any
performance test, return the instrument to the nearest Agilent
Technologies Sales/Service Office for repair.
Instrument Specification
Specifications are the performance characteristics of the
instrument that are certified. These specifications, listed in
“Specifications” on page 53, are the performance standards or limits
against which the Agilent 81663A DFB Laser Source Module
can be tested. The specifications also list some supplemental
characteristics of the Agilent 81663A DFB Laser Source Module.
Supplemental characteristics should be considered as
additional information.
Any changes in the specifications due to manufacturing
changes, design, or traceability to the National Institute of
Standards and Technology (NIST), will be covered in a manual
change supplement, or revised manual. Such specifications
supersede any that were previously published.
Instrument/Accessory Recommended Model Required
Characterisics
Alternative Models
Multimeter Mainframe Agilent 8163B Agilent 8163A, Agilent 8164A/B,
Agilent 8166A/B
Wavelength Meter Agilent 86122A Agilent 86120C
Singlemode Fibers Agilent 81113PC
Connector Interfaces Agilent 81000FI
Agilent 81000SI

3
Agilent DFB Laser Source Module User’s Guide 19
Performance Test Instructions
The performance tests given in this section include the
Wavelength Repeatability Test and the Wavelength Stability
Test. Perform each step in the order given, using the
corresponding test equipment.
All Wavelength Tests
Make sure that the cable connector, detectors and adapters are
clean.
1Connect the output of the DFB Laser Source Module to the
input of the wavelength meter.
General Settings for the wavelength meter
Set up the wavelength meter as follows. Please refer to the user
guide for the wavelength meter if you need further instructions.
2Set the display to show peak wavelength.
3Set the medium to Vacuum.
Wavelength Repeatability Test
1Move to the DFB-Source channel of the Agilent 8163A/B
8164A/B or 8166A/B mainframe and press Menu.
2Set the Wavelength mode to Offset and adjust the Power to
less than the maximum displayed level of the wavelength
meter. The minimum setting for the DFB power may be used.
3Close the Menu.
4Press the key beside the laser output to switch on the laser
ouput.
5Adjust the frequency offset to the first value given in the test
record in column "from wavelength".
NOTE
•Make sure that all the optical connections used in the the test setups
given in the procedures are dry and clean. Refer to the “Cleaning
Information” on page 25.
•DO NOT USE INDEX MATCHING OIL.
•Turn the instruments on, enable the laser and allow the instruments to
warm up for at least 60 minutes.
•The ambient temperature must be constant (±1K) during the tests.

20 Agilent DFB Laser Source Module User’s Guide
3
6Wait until the wavelength meter has settled. Then measure
the wavelength and note the result in the test record as the
reference wavelength, "REF".
7Set the frequency offset of the DFB Source module to any
value in its range (in the test record, this is given in column
"from wavelength").
8Set the frequency offset of the DFB Source back to the
reference frequency and wait until the Wavelength Meter has
settled.
9Repeat steps 5 to 8 for all frequency offsets given in the test
record.
10 From all the wavelength measurements, pick the largest
measured value and the smallest measured value.
11 Calculate the wavelength repeatability by subtracting the
largest measured value from the smallest measured value.
Wavelength Stability Test
1Move to the DFB-Source channel of the Agilent 8163A/B,
8164A/B or 8166A/B Lightwave Multimeter Mainframe and
press Menu.
2Set the Wavelength mode to Offset and adjust the Power to
less than the maximum displayed level of the wavelength
meter. The minimum setting for the DFB power may be used.
3Close the Menu.
4Press λ∅λ0
5Press the key beside the laser output to switch on the laser
ouput.
6Every minute for 15 minutes, note the Wavelength Meter
reading in the test record.
7From all the wavelength measurements, pick the largest
measured value and the smallest measured value.
8Calculate the wavelength stability by subtracting the largest
measured value from the smallest measured value.