Keysight 81663A
DFB Laser Source Module
User Guide
Notices
CAUTION
WARNING
© Keysight Technologies 2017
No part of this manual may be reproduced
in any form or by any means (including
electronic storage and retrieval or translation into a foreign language) without prior
agreement and written consent from
Keysight Technologies as governed by
United States and international copyright
laws.
Manual Part Number
81661-90A15
Edition
Edition 10.0, January 2017
Keysight Technologies Deutschland GmbH
Herrenberger Strasse 130,
71034 Böblingen, Germany
Technology Licenses
The hard ware and/or software described in
this document are furnished under a
license and may be used or copied only in
accordance with the terms of such license.
U.S. Government Rights
The Software is “commercial computer
software,” as defined by Federal Acquisition
Regulation (“FAR”) 2.101. Pursuant to FAR
12.212 and 27.405-3 and Department of
Defense FAR Supplement
(“DFARS”) 227.7202, the U.S. government
acquires commercial computer software
under the same terms by which the software is customarily provided to the public.
Accordingly, Keysight provides the Software to U.S. government customers under
its standard commercial license, which is
embodied in its End User License Agreement (EULA), a copy of which can be found
at http://www.keysight.com/find/sweula.
The license set forth in the EULA represents
the exclusive authority by which the U.S.
government may use, modify, distribute, or
disclose the Software. The EULA and the
license set forth therein, does not require
or permit, among other things, that Keysight: (1) Furnish technical information
related to commercial computer software
or commercial computer software documentation that is not customarily provided
to the public; or (2) Relinquish to, or otherwise provide, the government rights in
excess of these rights customarily provided
to the public to use, mod ify, reproduce,
release, perform, display, or d isclose commercial computer software or commercial
computer software documentation. No
additional government requirements
beyond those set forth in the EULA shall
apply, except to the extent that those
terms, rights, or licenses are explicitly
required from all providers of commercial
computer software pursuant to the FAR and
the DFARS and are set forth specifically in
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shall be under no obligation to update,
revise or otherwise modify the Software.
With respect to any technical data as
defined by FAR 2.101, pursuant to FAR
12.211 and 27.404.2 and DFARS 227.7102,
the U.S. government acquires no greater
than Limited Rights as defined in FAR
27.401 or DFAR 227.7103-5 (c), as applicable in any technical data.
Warranty
THE MATERIAL CONTAINED IN THIS
DOCUMENT IS PROVIDED "AS IS," AND IS
SUBJECT TO BEING CHANGED, WITHOUT
NOTICE, IN FUTURE EDITIONS. FURTHER,
TO THE MAXIMUM EXTENT PERMITTED BY
APPLICABLE LAW, KEYSIGHT DISCLAIMS
ALL WARRANTIES, EITHER EXPRESS OR
IMPLIED WITH REGARD TO THIS MANUAL
AND ANY INFORMATION CONTAINED
HEREIN, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF
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INCIDENTAL OR CONSEQUENTIAL
DAMAGES IN CONNECTION WITH THE
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THIS DOCUMENT OR ANY INFORMATION
CONTAINED HEREIN. SHOULD KEYSIGHT
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TERMS COVERING THE MATERIAL IN THIS
DOCUMENT THAT CONFLICT WITH THESE
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SEPARATE AGREEMENT WILL CONTROL.
Safety Notices
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.
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.
2 Keysight DFB Laser Source Module User’s Guide
Contents
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 Laser Source Modules 10
Laser Safety Labels 11
Laser Class 1M 11
What is a Laser Source Module? 12
A Description of the Front Panel 12
Optical Output 13
Operation Note 15
Maintaining Wavelength Accuracy Below Maximum Power 15
Keysight Technologies Sales and Service Offices 17
2 Accessories
Recommended Connector Interfaces 20
Wavelength Options 21
3 Performance Tests
Equipment Required 24
Test Record 25
Keysight DFB Laser Source Module User’s Guide 3
Contents
Test Failure 26
Instrument Specification 27
Performance Test Instructions 28
All Wavelength Tests 28
Wavelength Repeatability Test 28
Wavelength Stability Test 29
Test Records 30
Test Records 33
4 Cleaning Information
Cleaning Instructions for this Instrument 37
Safety Precautions 38
Why is it important to clean optical devices? 39
What do I need for proper cleaning? 40
Standard Cleaning Equipment 40
Additional Cleaning Equipment 43
Preserving Connectors 45
Cleaning Instrument Housings 46
Which Cleaning Procedure should I use? 47
Light dirt 47
Heavy dirt 47
How to clean connectors 48
Preferred Procedure 48
Procedure for Stubborn Dirt 49
An Alternative Procedure 49
How to clean connector adapters 50
Preferred Procedure 50
Procedure for Stubborn Dirt 50
4 Keysight DFB Laser Source Module User’s Guide
Contents
How to clean connector interfaces 51
Preferred Procedure 51
Procedure for Stubborn Dirt 51
How to clean bare fiber adapters 52
Preferred Procedure 52
Procedure for Stubborn Dirt 52
How to clean lenses 53
Preferred Procedure 53
Procedure for Stubborn Dirt 53
How to clean instruments with a fixed connector interface 54
How to clean instruments with an optical glass plate 55
How to clean instruments with a physical contact interface 56
Preferred Procedure 56
Procedure for Stubborn Dirt 56
How to clean instruments with a recessed lens interface 58
Preferred Procedure 58
Procedure for Stubborn Dirt 58
How to clean optical devices which are sensitive to mechanical
stress and pressure 59
Preferred Procedure 59
Procedure for Stubborn Dirt 59
Alternative Procedure 59
How to clean metal filters or attenuator gratings 60
Preferred Procedure 60
Procedure for Stubborn Dirt 60
Additional Cleaning Information 61
How to clean bare fiber ends 61
How to clean large area lenses and mirrors 61
Keysight DFB Laser Source Module User’s Guide 5
Contents
Other Cleaning Hints 63
Making the connection 63
Lens cleaning papers 63
Immersion oil and other index matching compounds 63
Cleaning the housing and the mainframe 64
5 Specifications
Definition of Terms 66
Wavelength tuning range 66
Wavelength display resolution 66
Wavelength repeatability 66
Wavelength stability 67
Max. output power 67
Power CW stability 67
Sidemode suppression ratio (SMSR) 68
Polarization extinction ratio (PER) 68
Coherence control 68
Modulation, digital 68
ON- switching with fast output power stabilization 69
Tuning Speed 69
DFB Source Module Specifications 70
Supplementary Performance Characteristics 71
6 Keysight DFB Laser Source Module User’s Guide
Keysight 81663A DFB Laser Source Module
User’s Guide
1 Getting Started with
DFB Laser Sources
Safety Considerations / 8
Initial Safety Information for Laser Source Modules / 10
Laser Safety Labels / 11
What is a Laser Source Module? / 12
Operation Note / 15
Keysight Technologies Sales and Service Offices / 17
This chapter introduces the features of the Keysight 81663A DFB Laser
Source Module.
1 Getting Started with DFB Laser Sources
WARNING
Safety Considerations
Safety Symbols
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. Keysight 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.
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.
Initial Inspection
8 Keysight DFB Laser Source Module User’s Guide
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.
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 Keysight Technologies Sales/Service Office.
WARNING
To avoid hazardous electrical shock, do not perform electrical tests when
WARNING
there are signs of shipping damage to any portion of the outer enclosure
(covers, panels, etc.).
You MUST return instruments with malfunctioning laser modules to a
Keysight Technologies Service Center for repair and calibration.
Line Power Requirements
The Keysight 81663A DFB Laser Source Module operates when installed in
the 8163A/B Lightwave Multimeter,8164A/B Lightwave Measurement
System, or 8166A/B Lightwave Multichannel System.
Operating Environment
The safety information in the 8163A/B Lightwave Multimeter, 8164A/B
Lightwave Measurement System, and 8166A/B Lightwave Multichannel
System User’s Guide summarizes the operating ranges for the Keysight
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.
Getting Started with DFB Laser Sources 1
Keysight DFB Laser Source Module User’s Guide 9
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 Keysight office, or see
http://about.keysight.com/en/companyinfo/environment/ takeback.shtml
for more information
1 Getting Started with DFB Laser Sources
Initial Safety Information for Laser Source Modules
The laser sources specified by this user guide are classified according to
IEC 60825- 1 (2007).
The laser sources comply with 21 CFR 1040.10 except for deviations
pursuant to Laser Notice No. 50, dated 2007- June- 24.
Table 1 DFB Laser Source Modules Laser Safety Information
Keysight 81663A
Laser type CW DFB Laser
Wavelength (±15nm) 1300 to 1650 nm
Max. CW output power* <28 mW
Beam waist diameter 9
Numerical aperture 0.1
Laser Class according to
IEC 60825-1 (2007)
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.
with built-in isolator
see display
μm
1M
Laser Safety Labels
Laser Class 1M
Figure 1 Laser Class 1M Safety Label - Keysight 81663A
10 Keysight DFB Laser Source Module User’s Guide
Getting Started with DFB Laser Sources 1
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.
Keysight DFB Laser Source Module User’s Guide 11
1 Getting Started with DFB Laser Sources
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 Keysight 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 these modules 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.
12 Keysight DFB Laser Source Module User’s Guide
Optical Output
Polarization Maintaining Fiber
Getting Started with DFB Laser Sources 1
The Keysight 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.
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
Figure 3 shows the symbol for straight contact connectors.
Keysight DFB Laser Source Module User’s Guide 13
1 Getting Started with DFB Laser Sources
CAUTION
Angled Contact Connectors
The Keysight 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.
If the contact connector on your instrument is angled, you can only use
cables with angled connectors with the instrument.
Figure 4 Angled Contact Connector Symbols (with PMF)
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.
14 Keysight DFB Laser Source Module User’s Guide
Operation Note
Getting Started with DFB Laser Sources 1
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 Keysight 86120C Multi-Wavelength Meter.
1 Set up your equipment as displayed in Figure 5.
Figure 5 Wavelength Accuracy Setup
2 On the user interface of your Keysight 8163A/B Lightwave Multimeter,
move to the DFB source module channel and perform the following
steps:
a Move to [P], and press Enter.
b Set 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.
c Move to [
d Set the wavelength to the value you require.
e Enable the laser by pressing the button on the front panel of the
module.
3 Allow 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.
Keysight DFB Laser Source Module User’s Guide 15
λ], and press Enter.
1 Getting Started with DFB Laser Sources
NOTE
4 On the user interface of your 8163A/B Lightwave Multimeter, perform
the following steps:
a Move to [P], and press Enter.
b Reduce the power for the module.
5 Allow 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:
a Move to [
b Adjust the wavelength value until the wavelength meter displays the
wavelength you require. Allow time for the wavelength meter to
settle.
λ], and press Enter.
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.
16 Keysight DFB Laser Source Module User’s Guide
Keysight Technologies Sales and Service Offices
For more information about Keysight Technologies test and measurement
products, applications, services, and for a current sales office listing, visit
our web site:
http://www.keysight.com/find/lightwave
You can also contact one of the following centers and ask for a test and
measurement sales representative.
Getting Started with DFB Laser Sources 1
United States 800 829 4444 (TEL)
800 829 4433 (FAX)
Canada 877 894 4414 (TEL)
800 746 4866 (FAX)
China 800 810 0189 (TEL)
800 820 2816 (FAX)
Europe +31 20 547 2111(TEL)
Japan (81) 426 56 7832 (TEL)
(81) 426 56 7840 (FAX)
Korea (080) 769 0800 (TEL)
(080) 769 0900 (FAX)
Latin America (305) 269 7500 (TEL)
Taiwan 0800 047 866 (TEL)
Other Asia Pacific countries (65) 6375 8100 (TEL)
(65) 6755 0042 (FAX)
Email:
tm_ap@keysight.com
Keysight DFB Laser Source Module User’s Guide 17
Keysight 81663A DFB Laser Source Module
User’s Guide
2 Accessories
Instrument Required / 16
The Keysight 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.
2 Accessories
Recommended Connector Interfaces
Figure 6 Recommended Connector Interfaces
20 Keysight DFB Laser Source Module User’s Guide
Wavelength Options
Accessories 2
Table 2 DFB Laser Source Modules Laser Safety Information
Keysight 81663A Option Number Center Wavelength
#131 1310
#149 1490
#151 1510
#155 1550
#162 1625
[nm]
Keysight DFB Laser Source Module User’s Guide 21
Keysight 81663A DFB Laser Source Module
User’s Guide
3 Performance Tests
Equipment Required / 26
Test Record / 27
Test Failure / 28
Instrument Specification / 29
Performance Test Instructions / 30
Test Records / 32
The procedures in this section test the optical performance of the
instrument. The complete specifications to which the Keysight 81663A
DFB Laser Source Module is tested are given in Specifications on page no
65. 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.
3 Performance Tests
Equipment Required
Equipment required for the performance test is listed below:
Table 3 Required Equipment
Instrument/Accessory Recommended Model Required
Characteristics
Multimeter Mainframe 8163B 8163A, 164A/B, 8166A/B
Wavelength Meter 86122A 86120C, 86122C
Singlemode Fibers 81113PC
Connector Interfaces 81000FI
81000SI
Alternative Models
26 Keysight DFB Laser Source Module User’s Guide
Test Record
Performance Tests 3
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 Keysight Technologies.
Keysight DFB Laser Source Module User’s Guide 27
3 Performance Tests
Test Failure
If the Keysight 81663A DFB Laser Source Module fails any performance
test, return the instrument to the nearest Keysight Technologies
Sales/Service Office for repair.
28 Keysight DFB Laser Source Module User’s Guide
Instrument Specification
Performance Tests 3
Specifications are the performance characteristics of the instrument that
are certified. These specifications, listed in Specifications on page no 65,
are the performance standards or limits against which the Keysight
81663A DFB Laser Source Module can be tested. The specifications also
list some supplemental characteristics of the Keysight 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.
Keysight DFB Laser Source Module User’s Guide 29
3 Performance Tests
NOTE
Performance Test Instructions
All Wavelength Tests
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.
• Make sure that all the optical connections used in the test setups
given in the procedures are dry and clean. Refer to the
Information
on page no 35.
Cleaning
• 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.
General Settings for the wavelength meter
Wavelength Repeatability Test
30 Keysight DFB Laser Source Module User’s Guide
Make sure that the cable connector, detectors and adapters are clean.
1 Connect the output of the DFB Laser Source Module to the input of the
wavelength meter.
Set up the wavelength meter as follows. Refer to the user guide for the
wavelength meter if you need further instructions.
2 Set the display to show peak wavelength.
3 Set the medium to Vacuum.
1 Move to the DFB- Source channel of the 8163A/B 8164A/B or
8166A/B mainframe and press Menu.
2 Set 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.
3 Close the Menu.
4 Press the key beside the laser output to switch on the laser output.
5 Adjust the frequency offset to the first value given in the test record in
6 Wait until the wavelength meter has settled. Then measure the
7 Set the frequency offset of the DFB Source module to any value in its
8 Set the frequency offset of the DFB Source back to the reference
9 Repeat steps 5 to 8 for all frequency offsets given in the test record.
10 From all the wavelength measurements, pick the largest measured
11 Calculate the wavelength repeatability by subtracting the largest
Wavelength Stability Test
1 1 Move to the DFB- Source channel of the 8163A/B, 8164A/B or
2 Set the Wavelength mode to Offset and adjust the Power to less than
3 Close the Menu.
4Press
5 Press the key beside the laser output to switch on the laser output.
6 Every minute for 15 minutes, note the Wavelength Meter reading in the
7 From all the wavelength measurements, pick the largest measured
8 Calculate the wavelength stability by subtracting the largest measured
Performance Tests 3
column “from wavelength”.
wavelength and note the result in the test record as the reference
wavelength, “REF”.
range (in the test record, this is given in column “from wavelength”).
frequency and wait until the Wavelength Meter has settled.
value and the smallest measured value.
measured value from the smallest measured value.
8166A/B Lightwave Multimeter Mainframe and press Menu.
the maximum displayed level of the wavelength meter. The minimum
setting for the DFB power may be used.
λ λ
0
test record.
value and the smallest measured value.
value from the smallest measured value.
Keysight DFB Laser Source Module User’s Guide 31
3 Performance Tests
Test Records
Performance Test for the Keysight 81663A
Page 1 of 4 Date ___________
Model Keysight 81663A DFB Laser Source module (_____.__ nm)
Serial No. _________________________ Ambient Temperature ___________°C
Options _________________________ Relative Humidity ___________ %
Firmware Rev. _________________________ Line Frequency ___________ Hz
Test Facility _________________________ Customer _________________________
Performed by _________________________ Report No _________________________
Special Notes ________________________________________________________________________________________________
________________________________________________________________________________________________
32 Keysight DFB Laser Source Module User’s Guide
________________________________________________________________________________________________
________________________________________________________________________________________________
________________________________________________________________________________________________
________________________________________________________________________________________________
________________________________________________________________________________________________
________________________________________________________________________________________________
________________________________________________________________________________________________
________________________________________________________________________________________________
________________________________________________________________________________________________
________________________________________________________________________________________________
________________________________________________________________________________________________
________________________________________________________________________________________________
________________________________________________________________________________________________
Performance Tests 3
Performance Test for the Keysight 81663A
Page 2 of 4
Description Model No. Trace No Cal. Due Date
1a Lightwave Multimeter 8163A/B ____________ ___________
1b Multichannel System 8166A/B ____________ ___________
1c Measurement System 8164A/B ____________ ___________
2a Wavelength Meter 81622A ____________ ___________
2b Wavelength Meter Keysight 86120C ____________ ___________
3 ____________________________ ____________ ____________ ___________
4 ____________________________ ____________ ____________ ___________
5 ____________________________ ____________ ____________ ___________
6 ____________________________ ____________ ____________ ___________
7 ____________________________ ____________ ____________ ___________
8 ____________________________ ____________ ____________ ___________
9 ____________________________ ____________ ____________ ___________
10 ____________________________ ____________ ____________ ___________
11 ____________________________ ____________ ____________ ___________
Test Equipment Used
12 ____________________________ ____________ ____________ ___________
Accessories # Product # Product # Product
Singemode Fibers 1 81113PC 1
Connector Interfaces 1 81000FI 1 81000SI
Keysight DFB Laser Source Module User’s Guide 33
3 Performance Tests
Performance Test for the Keysight 81663A
Page 3 of 4
Test
Number
I Wavelength Repeatability nm nm
2 Wavelength Stability, 15min nm nm
Test Description Minimum
Specification.
measured at ________nm
(-50 GHz offset frequency) ________ < 0.01 m,
measured at ________nm
(0 GHz offset frequency) ________ < 0.01 m,
measured at ________nm
(+50 GHz offset frequency) ________ < 0.01 m,
measured at ________nm
(0 GHz offset frequency) ________ < 0.01 m,
Result Maximum
Specification.
Measurement
Uncertainty
34 Keysight DFB Laser Source Module User’s Guide
Test Records
Performance Tests 3
Repeatability of
Df = -50 GHz (= reference)
Initial Setting REF = nm Initial Setting REF = nm
from -30 GHz to -50 Ghz nm from -30 GHz to -50 Ghz nm
from -10 GHz to -50 GHz nm from -10 GHz to -50 GHz nm
from 0 GHz to -50 GHz nm from 0 GHz to -50 GHz nm
from +10 GHz to -50 GHz nm from +10 GHz to -50 GHz nm
from +30 GHz to -50 GHz nm from +30 GHz to -50 GHz nm
from +50 GHz to -50 GHz nm from +50 GHz to -50 GHz nm
largest measured value nm largest measured value nm
smallest measured value nm smallest measured value nm
Wavelength Repeatability nm Wavelength Repeatability nm
Measurement Result Repeatability of
Df = 0 GHz (= reference)
Measurement Result
Keysight DFB Laser Source Module User’s Guide 35
3 Performance Tests
Performance Test for the Keysight 81663A
Page 4 of 4
Repeatability of
Df = +50 GHz (= reference)
Initial Setting REF = nm Start Value nm
from -30 GHz to -50 Ghz nm 1. nm
from -10 GHz to -50 GHz nm 2. nm
from 0 GHz to -50 GHz nm 3. nm
from +10 GHz to -50 GHz nm 4. nm
from +30 GHz to -50 GHz nm 5. nm
from +50 GHz to -50 GHz nm 6. nm
largest measured value nm 7. nm
smallest measured value nm 8. nm
Wavelength Repeatability nm 9. nm
Measurement Result Stability of ______.__nm Measurement Result
10. nm
11. nm
12. nm
13. nm
14. nm
15. nm
largest measured value nm
smallest measured value nm
Wavelength Repeatability nm
36 Keysight DFB Laser Source Module User’s Guide
Keysight 81663A DFB Laser Source Module
User’s Guide
4 Cleaning Information
Cleaning Instructions for this Instrument / 37
Safety Precautions / 38
Why is it important to clean optical devices? / 39
What do I need for proper cleaning? / 40
Preserving Connectors / 45
Cleaning Instrument Housings / 46
Safety Precautions / 38
Why is it important to clean optical devices? / 39
What do I need for proper cleaning? / 40
Preserving Connectors / 45
Cleaning Instrument Housings / 46
Which Cleaning Procedure should I use? / 47
How to clean connectors / 48
How to clean connector interfaces / 51
How to clean bare fiber adapters / 52
How to clean lenses / 53
How to clean instruments with a fixed connector interface / 54
How to clean instruments with an optical glass plate / 55
How to clean instruments with a physical contact interface / 56
How to clean instruments with a recessed lens interface / 58
How to clean optical devices which are sensitive to mechanical stress and
pressure / 59
4 Cleaning Information
How to clean metal filters or attenuator gratings / 60
Additional Cleaning Information / 61
Other Cleaning Hints / 63
The following Cleaning Instructions contain some general safety
precautions, which must be observed during all phases of cleaning.
Consult your specific optical device manuals or guides for full information
on safety matters.
Please try, whenever possible, to use physically contacting connectors,
and dry connections. Clean the connectors, interfaces, and bushings
carefully after use.
If you are unsure of the correct cleaning procedure for your optical device,
we recommend that you first try cleaning a dummy or test device.
Keysight Technologies assume no liability for the customer’s failure to
comply with these requirements.
36 Keysight DFB Laser Source Module User’s Guide
Cleaning Instructions for this Instrument
The Cleaning Instructions apply to a number of different types of Optical
Equipment.
How to clean instruments with a physical contact interface on page 56 is
particularly relevant to this module.
Cleaning Information 4
Keysight DFB Laser Source Module User’s Guide 37
4 Cleaning Information
Safety Precautions
Please follow the following safety rules:
• Do not remove instrument covers when operating.
• Ensure that the instrument is switched off throughout the cleaning
procedures.
• Use of controls or adjustments or performance of procedures other
than those specified may result in hazardous radiation exposure.
• Make sure that you disable all sources when you are cleaning any
optical interfaces.
• Under no circumstances look into the end of an optical device attached
to optical outputs when the device is operational. The laser radiation is
not visible to the human eye, but it can seriously damage your eyesight.
• To prevent electrical shock, disconnect the instrument from the mains
before cleaning. Use a dry cloth, or one slightly dampened with water,
to clean the external case parts. Do not attempt to clean internally.
• Do not install parts or perform any unauthorized modification to optical
devices.
• Refer servicing only to qualified and authorized personnel.
38 Keysight DFB Laser Source Module User’s Guide
Why is it important to clean optical devices?
In transmission links optical fiber cores are about 9 mm (0.00035") in
diameter. Dust and other particles, however, can range from tenths to
hundredths of microns in diameter.
Their comparative size means that they can cover a part of the end of a
fiber core, and as a result will reduce the performance of your system.
Furthermore, the power density may burn dust into the fiber and cause
additional damage (for example, 0 dBm optical power in a single mode
fiber causes a power density of approximately 16 million W/m2). If this
happens, measurements become inaccurate and non- repeatable.
Cleaning is, therefore, an essential yet difficult task. Unfortunately, when
comparing most published cleaning recommendations, you will discover
that they contain several inconsistencies. In this section, we want to
suggest ways to help you clean your various optical devices, and thus
significantly improve the accuracy and repeatability of your lightwave
measurements.
Cleaning Information 4
Keysight DFB Laser Source Module User’s Guide 39
4 Cleaning Information
What do I need for proper cleaning?
Some Standard Cleaning Equipment is necessary for cleaning your
instrument. For certain cleaning procedures, you may also require certain
Additional Cleaning Equipment.
Standard Cleaning Equipment
Before you can start your cleaning procedure you need the following
standard equipment:
• Dust and shutter caps
• Isopropyl alcohol
• Cotton swabs
• Soft tissues
• Pipe cleaner
• Compressed air
40 Keysight DFB Laser Source Module User’s Guide
Dust and shutter caps
All of Keysight Technologies’ lightwave instruments are delivered with
either laser shutter caps or dust caps on the light-wave adapter. Any
cables come with covers to protect the cable ends from damage or
contamination.
We suggest these protected coverings should be kept on the equipment at
all times, except when your optical device is in use. Be careful when
replacing dust caps after use. Do not press the bottom of the cap onto the
fiber too hard, as any dust in the cap can scratch or pollute your fiber
surface. If you need further dust caps, contact your nearest Keysight
Technologies sales office.
Isopropyl alcohol
This solvent is usually available from any local pharmaceutical supplier or
chemist's shop.
If you use isopropyl alcohol to clean your optical device, do not
immediately dry the surface with compressed air (except when you are
cleaning very sensitive optical devices). This is because the dust and the
dirt is solved and will leave behind filmy deposits after the alcohol is
evaporated. You should therefore first remove the alcohol and the dust
with a soft tissue, and then use compressed air to blow away any
remaining filaments.
If possible avoid using denatured alcohol containing additives. Instead,
apply alcohol used for medical purposes.
Never try to drink this alcohol, as it may seriously damage your health.
Do not use any other solvents, as some may damage plastic materials and
claddings. Acetone, for example, will dissolve the epoxy used with fiber
optic connectors. To avoid damage, only use isopropyl alcohol.
Cotton swabs
We recommend that you use swabs such as Q-tips or other cotton swabs
normally available from local distributors of medical and hygiene products
(for example, a supermarket or a chemist's shop). You may be able to
obtain various sizes of swab. If this is the case, select the smallest size for
your smallest devices.
Ensure that you use natural cotton swabs. Foam swabs will often leave
behind filmy deposits after cleaning.
Use care when cleaning, and avoid pressing too hard onto your optical
device with the swab. Too much pressure may scratch the surface, and
could cause your device to become misaligned. It is advisable to rub gently
over the surface using only a small circular movement.
Swabs should be used straight out of the packet, and never used twice.
This is because dust and dirt in the atmosphere, or from a first cleaning,
may collect on your swab and scratch the surface of your optical device.
Cleaning Information 4
Soft tissues
These are available from most stores and distributors of medical and
hygiene products such as supermarkets or chemists' shops.
We recommend that you do not use normal cotton tissues, but multi
layered soft tissues made from non-recycled cellulose. Cellulose tissues
are very absorbent and softer. Consequently, they will not scratch the
surface of your device over time.
Use care when cleaning, and avoid pressing on your optical device with
the tissue. Pressing too hard may lead to scratches on the surface or
misalignment of your device. Just rub gently over the surface using a small
circular movement.
Keysight DFB Laser Source Module User’s Guide 41
4 Cleaning Information
Use only clean, fresh soft tissues and never apply them twice. Any dust
and dirt from the air which collects on your tissue, or which has gathered
after initial cleaning, may scratch and pollute your optical device.
Pipe cleaner
Pipe cleaners can be purchased from tobacconists, and come in various
shapes and sizes. The most suitable one to select for cleaning purposes
has soft bristles, which will not produces scratches. There are many
different kinds of pipe cleaner available from tobacco shops.
The best way to use a pipe cleaner is to push it in and out of the device
opening (for example, when cleaning an interface). While you are cleaning,
you should slowly rotate the pipe cleaner.
Only use pipe cleaners on connector interfaces or on feed through
adapters. Do not use them on optical head adapters, as the center of a
pipe cleaner is hard metal and can damage the bottom of the adapter.
Your pipe cleaner should be new when you use it. If it has collected any
dust or dirt, this can scratch or contaminate your device.
The tip and center of the pipe cleaner are made of metal. Avoid
accidentally pressing these metal parts against the inside of the device, as
this can cause scratches.
Compressed air
Compressed air can be purchased from any laboratory supplier.
It is essential that your compressed air is free of dust, water and oil. Only
use clean, dry air. If not, this can lead to filmy deposits or scratches on the
surface of your connector. This will reduce the performance of your
transmission system.
When spraying compressed air, hold the can upright. If the can is held at a
slant, propellant could escape and dirty your optical device. First spray
into the air, as the initial stream of compressed air could contain some
condensation or propellant. Such condensation leaves behind a filmy
deposit.
Please be friendly to your environment and use a CFC-free aerosol.
42 Keysight DFB Laser Source Module User’s Guide
Additional Cleaning Equipment
Some Cleaning Procedures need the following equipment, which is not
required to clean each instrument:
• Microscope with a magnification range about 50X up to 300X
• Ultrasonic bath
• Warm water and liquid soap
• Premoistened cleaning wipes
• Polymer film
• Infrared Sensor Card
Microscope with a magnification range about 50X up to 300X
A microscope can be found in most photography stores, or can be
obtained through or specialist mail order companies. Special fiber-scopes
are available from suppliers of splicing equipment.
Ideally, the light source on your microscope should be very flexible. This
will allow you to examine your device closely and from different angles. A
microscope helps you to estimate the type and degree of dirt on your
device. You can use a microscope to choose an appropriate cleaning
method, and then to examine the results. You can also use your
microscope to judge whether your optical device (such as a connector) is
severely scratched and is, therefore, causing inaccurate measurements.
Cleaning Information 4
Ultrasonic bath
Ultrasonic baths are also available from photography or laboratory
suppliers or specialist mail order companies.
An ultrasonic bath will gently remove fat and other stubborn dirt from your
optical devices. This helps increase the life span of the optical devices.
Only use isopropyl alcohol in your ultrasonic bath, as other solvents may
damage.
Keysight DFB Laser Source Module User’s Guide 43
4 Cleaning Information
Warm water and liquid soap
Only use water if you are sure that there is no other way of cleaning your
optical device without corrosion or damage. Do not use hot water, as this
may cause mechanical stress, which can damage your optical device.
Ensure that your liquid soap has no abrasive properties or perfume in it.
You should also avoid normal washing-up liquid, as it can cover your
device in an iridescent film after it has been air-dried.
Some lenses and mirrors also have a special coating, which may be
sensitive to mechanical stress, or to fat and liquids. For this reason we
recommend you do not touch them. If you are not sure how sensitive your
device is to cleaning, please contact the manufacturer or your sales
distributor.
Premoistened cleaning wipes
Use pre-moistened cleaning wipes as described in each individual
cleaning procedure. Cleaning wipes may be used in every instance where a
moistened soft tissue or cotton swab is applied.
Polymer film
Infrared Sensor Card
44 Keysight DFB Laser Source Module User’s Guide
Polymer film is available from laboratory suppliers or specialist mail order
companies.
Using polymer film is a gentle method of cleaning extremely sensitive
devices, such as reference reflectors and mirrors.
Infrared sensor cards are available from laboratory suppliers or specialist
mail order companies.
With this card you are able to control the shape of laser light emitted. The
invisible laser beam is projected onto the sensor card, then becomes
visible to the normal eye as a round spot.
Take care never to look into the end of a fiber or any other optical
component, when they are in use. This is because the laser can seriously
damage your eyes.
Preserving Connectors
Making Connections
Dust Caps and Shutter Caps
Cleaning Information 4
Listed below are some hints on how best to keep your connectors in the
best possible condition.
Before you make any connection you must ensure that all cables and
connectors are clean. If they are dirty, use the appropriate cleaning
procedure.
When inserting the ferrule of a patch-cord into a connector or an adapter,
make sure that the fiber end does not touch the outside of the mating
connector or adapter. Otherwise you will rub the fiber end against an
unsuitable surface, producing scratches and dirt deposits on the surface of
your fiber.
Be careful when replacing dust caps after use. Do not press the bottom of
the cap onto the fiber as any dust in the cap can scratch or dirty your fiber
surface.
When you have finished cleaning, put the dust cap back on, or close the
shutter cap if the equipment is not going to be used immediately.
Keep the caps on the equipment always when it is not in use.
All of Keysight Technologies’ lightwave instruments and accessories are
shipped with either laser shutter caps or dust caps. If you need additional
or replacement dust caps, contact your nearest Keysight Technologies
Sales/Service Office.
Immersion Oil and Other Index Matching Compounds
Where it is possible, do not use immersion oil or other index matching
compounds with your device. They are liable to impair and dirty the
surface of the device. In addition, the characteristics of your device can be
changed and your measurement results affected.
Keysight DFB Laser Source Module User’s Guide 45
4 Cleaning Information
Cleaning Instrument Housings
Use a dry and very soft cotton tissue to clean the instrument housing and
the keypad. Do not open the instruments as there is a danger of electric
shock, or electrostatic discharge. Opening the instrument can cause
damage to sensitive components, and in addition your warranty will be
voided.
46 Keysight DFB Laser Source Module User’s Guide
Which Cleaning Procedure should I use?
Light dirt
If you just want to clean away light dirt, observe the following procedure
for all devices:
• Use compressed air to blow away large particles.
• Clean the device with a dry cotton swab.
• Use compressed air to blow away any remaining filament left by the
swab.
Heavy dirt
If the above procedure is not enough to clean your instrument, follow one
of the procedures below. Please consult Cleaning Instructions for this
Instrument on page 37 for the procedure relevant for this instrument.
Cleaning Information 4
If you are unsure of how sensitive your device is to cleaning, please contact
the manufacturer or your sales distributor.
Keysight DFB Laser Source Module User’s Guide 47
4 Cleaning Information
WARNING
How to clean connectors
Cleaning connectors is difficult as the core diameter of a single-mode fiber
is only about 9 mm. This generally means you cannot see streaks or
scratches on the surface. To be certain of the condition of the surface of
your connector and to check it after cleaning, you need a microscope.
In the case of scratches, or of dust that has been burnt onto the surface of
the connector, you may have no option but to polish the connector. This
depends on the degree of dirtiness, or the depth of the scratches. This is a
difficult procedure and should only be performed by skilled personal, and
as a last resort as it wears out your connector.
Never look into the end of an optical cable that is connected to an active
source.
To assess the projection of the emitted light beam you can use an infrared
sensor card. Hold the card approximately 5 cm from the output of the
connector. The invisible emitted light is project onto the card and becomes
visible as a small circular spot.
48 Keysight DFB Laser Source Module User’s Guide
Preferred Procedure
Use the following procedure on most occasions:
1 Clean the connector by rubbing a new, dry cotton-swab over the
surface using a small circular movement.
2 Blow away any remaining lint with compressed air.
Procedure for Stubborn Dirt
Use this procedure particularly when there is greasy dirt on the connector:
1 Moisten a new cotton-swab with isopropyl alcohol.
2 Clean the connector by rubbing the cotton-swab over the surface
using a small circular movement.
3 Take a new, dry soft-tissue and remove the alcohol, dissolved sediment
and dust, by rubbing gently over the surface using a small circular
movement.
4 Blow away any remaining lint with compressed air.
An Alternative Procedure
A better, more gentle, but more expensive cleaning procedure is to use an
ultrasonic bath with isopropyl alcohol.
1 Hold the tip of the connector in the bath for at least three minutes.
2 Take a new, dry soft-tissue and remove the alcohol, dissolved sediment
and dust, by rubbing gently over the surface using a small circular
movement.
3 Blow away any remaining lint with compressed air.
Cleaning Information 4
Keysight DFB Laser Source Module User’s Guide 49
4 Cleaning Information
CAUTION
How to clean connector adapters
Some adapters have an anti-reflection coating on the back to reduce
back reflection. This coating is extremely sensitive to solvents and
mechanical abrasion. Extra care is needed when cleaning these adapters.
Preferred Procedure
Use the following procedure on most occasions:
1 Clean the adapter by rubbing a new, dry cotton swab over the surface
2 Blow away any remaining lint with compressed air.
using a small circular movement.
50 Keysight DFB Laser Source Module User’s Guide
Procedure for Stubborn Dirt
Use this procedure particularly when there is greasy dirt on the adapter:
1 Moisten a new pipe-cleaner with isopropyl alcohol.
2 Clean the adapter by rubbing the cotton-swab over the surface using a
small circular movement.
3 Take a new, dry soft tissue and remove the alcohol, dissolved sediment
and dust, by rubbing gently over the surface using a small circular
movement.
4 Blow away any remaining lint with compressed air.
How to clean connector interfaces
CAUTION
Be careful when using pipe-cleaners, as the core and the bristles of the
pipe-cleaner are hard and can damage the interface.
Do not use pipe-cleaners on optical head adapters, as the hard core of
normal pipe cleaners can damage the bottom of an adapter.
Preferred Procedure
Use the following procedure on most occasions:
1 Clean the interface by pushing and pulling a new, dry pipe-cleaner into
the opening. Rotate the pipe-cleaner slowly as you do this.
2 Then clean the interface by rubbing a new, dry cotton-swab over the
surface using a small circular movement.
3 Blow away any remaining lint with compressed air.
Cleaning Information 4
Procedure for Stubborn Dirt
Use this procedure particularly when there is greasy dirt on the interface:
1 Moisten a new pipe-cleaner with isopropyl alcohol.
2 Clean the interface by pushing and pulling the pipe-cleaner into the
opening. Rotate the pipe-cleaner slowly as you do this.
3 Moisten a new cotton-swab with isopropyl alcohol.
4 Clean the interface by rubbing the cotton-swab over the surface using
a small circular movement.
5 Using a new, dry pipe-cleaner, and a new, dry cotton-swab remove the
alcohol, any dissolved sediment and dust.
6 Blow away any remaining lint with compressed air.
Keysight DFB Laser Source Module User’s Guide 51
4 Cleaning Information
CAUTION
CAUTION
How to clean bare fiber adapters
Bare fiber adapters are difficult to clean. Protect from dust unless they are
in use.
Never use any kind of solvent when cleaning a bare fiber adapter as
solvents can:
• Damage the foam inside some adapters.
• Deposit dissolved dirt in the groove, which can then dirty the surface
Preferred Procedure
Use the following procedure on most occasions:
1 Blow away any dust or dirt with compressed air.
of an inserted fiber.
Procedure for Stubborn Dirt
Use this procedure particularly when there is greasy dirt on the adapter:
1 Clean the adapter by pushing and pulling a new, dry pipe-cleaner into
the opening. Rotate the pipe-cleaner slowly as you do this.
Be careful when using pipe-cleaners, as the core and the bristles of the
pipe-cleaner are hard and can damage the adapter.
2 Clean the adapter by rubbing a new, dry cotton-swab over the surface
using a small circular movement.
3 Blow away any remaining lint with compressed air.
52 Keysight DFB Laser Source Module User’s Guide
How to clean lenses
Preferred Procedure
Procedure for Stubborn Dirt
Cleaning Information 4
Some lenses have special coatings that are sensitive to solvents, grease,
liquid and mechanical abrasion. Take extra care when cleaning lenses with
these coatings.
Lens assemblies consisting of several lenses are not normally sealed.
Therefore, use as little alcohol as possible, as it can get between the lenses
and in doing so can change the properties of projection.
Use the following procedure on most occasions:
1 Clean the lens by rubbing a new, dry cotton- swab over the surface
using a small circular movement.
2 Blow away any remaining lint with compressed air.
Use this procedure particularly when there is greasy dirt on the lens:
1 1 Moisten a new cotton- swab with isopropyl alcohol.
2 Clean the lens by rubbing the cotton- swab over the surface using a
small circular movement.
3 Using a new, dry cotton- swab remove the alcohol, any dissolved
sediment and dust.
4 Blow away any remaining lint with compressed air.
Keysight DFB Laser Source Module User’s Guide 53
4 Cleaning Information
CAUTION
How to clean instruments with a fixed connector interface
You should only clean instruments with a fixed connector interface when it
is absolutely necessary. This is because it is difficult to remove any used
alcohol or filaments from the input of the optical block.
It is important, therefore, to keep dust caps on the equipment at all times,
except when your optical device is in use.
If you do discover filaments or particles, the only way to clean a fixed
connector interface and the input of the optical block is to use compressed
air.
If there are fluids or fat in the connector, please refer the instrument to the
skilled personnel of Keysight’s service team.
Only use clean, dry compressed air. Make sure that the air is free of dust,
water, and oil. If the air that you use is not clean and dry, this can lead to
filmy deposits or scratches on the surface of your connector interface.
This will degrade the performance of your transmission system.
Never try to open the instrument and clean the optical block by yourself,
because it is easy to scratch optical components, and cause them to be
misaligned.
54 Keysight DFB Laser Source Module User’s Guide
How to clean instruments with an optical glass plate
Some instruments, for example, the optical heads from Keysight
Technologies have an optical glass plate to protect the sensor. Clean this
glass plate in the same way as optical lenses (see How to clean lenses on
page 53).
Cleaning Information 4
Keysight DFB Laser Source Module User’s Guide 55
4 Cleaning Information
WARNING
How to clean instruments with a physical contact interface
Remove any connector interfaces from the optical output of the instrument
before you start the cleaning procedure.
Cleaning interfaces is difficult as the core diameter of a single-mode fiber
is only about 9 mm. This generally means you cannot see streaks or
scratches on the surface. To be certain of the degree of pollution on the
surface of your interface and to check whether it has been removed after
cleaning, you need a microscope.
Never look into an optical output, because this can seriously damage
your eyesight.
To assess the projection of the emitted light beam you can use an
infrared sensor card. Hold the card approximately 5 cm from the
interface. The invisible emitted light is projected onto the card and
becomes visible as a small circular spot.
To assess the projection of the emitted light beam you can use an infrared
sensor card. Hold the card approximately 5 cm from the interface. The
invisible emitted light is project onto the card and becomes visible as a
small circular spot.
56 Keysight DFB Laser Source Module User’s Guide
Preferred Procedure
Use the following procedure on most occasions:
1 Clean the interface by rubbing a new, dry cotton- swab over the
surface using a small circular movement.
2 Blow away any remaining lint with compressed air.
Procedure for Stubborn Dirt
Use this procedure particularly when there is greasy dirt on the interface:
1 Moisten a new cotton- swab with isopropyl alcohol.
2 Clean the interface by rubbing the cotton- swab over the surface using
a small circular movement.
Cleaning Information 4
3 Take a new, dry soft- tissue and remove the alcohol, dissolved
sediment and dust, by rubbing gently over the surface using a small
circular movement.
4 Blow away any remaining lint with compressed air.
Keysight DFB Laser Source Module User’s Guide 57
4 Cleaning Information
WARNING
How to clean instruments with a recessed lens interface
For instruments with a deeply recessed lens interface (for example the
Keysight 81633A and 81634A Power Sensors) do NOT follow this
procedure. Alcohol and compressed air could damage your lens even
further.
Keep your dust and shutter caps on, when your instrument is not in use.
This should prevent it from getting too dirty. If you must clean such
instruments, please refer the instrument to the skilled personnel of
Keysight’s service team.
Preferred Procedure
Use the following procedure on most occasions:
1 Blow away any dust or dirt with compressed air. If this is not sufficient,
then
2 Clean the interface by rubbing a new, dry cotton- swab over the
surface using a small circular movement.
3 Blow away any remaining lint with compressed air.
58 Keysight DFB Laser Source Module User’s Guide
Procedure for Stubborn Dirt
Use this procedure particularly when there is greasy dirt on the interface,
and using the procedure for light dirt is not sufficient. Using isopropyl
alcohol should be your last choice for recessed lens interfaces because of
the difficulty of cleaning out any dirt that is washed to the edge of the
interface:
1 Moisten a new cotton- swab with isopropyl alcohol.
2 Clean the interface by rubbing the cotton- swab over the surface using
a small circular movement.
3 Take a new, dry soft- tissue and remove the alcohol, dissolved
sediment and dust, by rubbing gently over the surface using a small
circular movement.
4 Blow away any remaining lint with compressed air.
Cleaning Information 4
How to clean optical devices which are sensitive to mechanical stress and pressure
Some optical devices, such as the Keysight 81000BR Reference Reflector,
which has a gold plated surface, are very sensitive to mechanical stress or
pressure. Do not use cotton- swabs, soft- tissues or other mechanical
cleaning tools, as these can scratch or destroy the surface.
Preferred Procedure
Use the following procedure on most occasions:
1 Blow away any dust or dirt with compressed air.
Procedure for Stubborn Dirt
To clean devices that are extremely sensitive to mechanical stress or
pressure you can also use an optical clean polymer film. This procedure is
time- consuming, but you avoid scratching or destroying the surface.
1 Put the film on the surface and wait at least 30 minutes to make sure
that the film has had enough time to dry.
2 Remove the film and any dirt with special adhesive tapes.
Alternative Procedure
For these types of optical devices you can often use an ultrasonic bath
with isopropyl alcohol. Only use the ultrasonic bath if you are sure that it
won't cause any damage anything to the device.
1 Put the device into the bath for at least three minutes.
2 Blow away any remaining liquid with compressed air.
If there are any streaks or drying stains on the surface, repeat the cleaning
procedure.
Keysight DFB Laser Source Module User’s Guide 59
4 Cleaning Information
How to clean metal filters or attenuator gratings
This kind of device is extremely fragile. A misalignment of the grating leads
to inaccurate measurements. Never touch the surface of the metal filter or
attenuator grating. Be very careful when using or cleaning these devices.
Do not use cotton- swabs or soft- tissues, as there is the danger that you
cannot remove the lint and that the device will be destroyed by becoming
mechanically distorted.
Preferred Procedure
Use the following procedure on most occasions:
1 Use compressed air at a distance and with low pressure to remove any
dust or lint.
Procedure for Stubborn Dirt
Do not use an ultrasonic bath as this can damage your device.
Use this procedure particularly when there is greasy dirt on the device:
1 Put the optical device into a bath of isopropyl alcohol, and wait at least
10 minutes.
2 Remove the fluid using compressed air at some distance and with low
pressure. If there are any streaks or drying stains on the surface, repeat
the whole cleaning procedure.
60 Keysight DFB Laser Source Module User’s Guide
Additional Cleaning Information
The following cleaning procedure may be used with other optical
equipment:
• How to clean bare fiber ends
• How to clean large area lenses and mirrors
How to clean bare fiber ends
Bare fiber ends are often used for splices or, together with other optical
components, to create a parallel beam. The end of a fiber can often be
scratched. You make a new cleave. To do this:
1 Strip off the cladding.
2 Take a new soft-tissue and moisten it with isopropyl alcohol.
3 Carefully clean the bare fiber with this tissue.
4 Make your cleave and immediately insert the fiber into your bare fiber
Cleaning Information 4
adapter in order to protect the surface from dirt.
How to clean large area lenses and mirrors
Some mirrors, as those from a monochromator, are very soft and sensitive.
Therefore, never touch them and do not use cleaning tools such as
compressed air or polymer film.
Some lenses have special coatings that are sensitive to solvents, grease,
liquid and mechanical abrasion. Take extra care when cleaning lenses with
these coatings.
Lens assemblies consisting of several lenses are not normally sealed.
Therefore, use as little liquid as possible, as it can get between the lenses
and in doing so can change the properties of projection.
Preferred Procedure
Use the following procedure on most occasions:
1 Blow away any dust or dirt with compressed air.
Keysight DFB Laser Source Module User’s Guide 61
4 Cleaning Information
CAUTION
Procedure for Stubborn Dirt
Use this procedure particularly when there is greasy dirt on the lens:
Only use water if you are sure that there is no other way of cleaning your
optical device without causing corrosion or damage.
Only use water if you are sure that there is no other way of cleaning your
optical device without causing corrosion or damage. Do not use hot
water, as this may cause mechanical stress, which can damage your
optical device.
Ensure that your liquid soap has no abrasive properties or perfume in it.
You should also avoid normal washing up liquid, as it can cover your
device in an iridescent film after it has been air dried.
Some lenses and mirrors also have a special coating, which may be
sensitive to mechanical stress, or to fat and liquids. For this reason we
recommend you do not touch them.
If you are not sure how sensitive your device is to cleaning, please
contact the manufacturer or your sales distributor
1 Moisten the lens or the mirror with water.
2 Put a little liquid soap on the surface and gently spread the liquid over
the whole area.
3 Wash off the emulsion with water, being careful to remove it all, as any
remaining streaks can impair measurement accuracy.
4 Take a new, dry soft- tissue and remove the water, by rubbing gently
over the surface using a small circular movement.
5 Blow away remaining lint with compressed air.
Alternative Procedure A
To clean lenses that are extremely sensitive to mechanical stress or
pressure you can also use an optical clean polymer film. This procedure is
time- consuming, but you avoid scratching or destroying the surface.
1 Put the film on the surface and wait at least 30 minutes to make sure
that the film has had enough time to dry.
2 Remove the film and any dirt with special adhesive tapes.
62 Keysight DFB Laser Source Module User’s Guide
Alternative Procedure B
If your lens is sensitive to water then:
1 Moisten the lens or the mirror with isopropyl alcohol.
2 Take a new, dry soft- tissue and remove the alcohol, dissolved
sediment and dust, by rubbing gently over the surface using a small
circular movement.
3 Blow away remaining lint with compressed air.
Cleaning Information 4
Keysight DFB Laser Source Module User’s Guide 63
4 Cleaning Information
Other Cleaning Hints
Making the connection
Selecting the correct cleaning method is an important element in
maintaining your equipment and saving you time and money. This
Appendix highlights the main cleaning methods, but cannot address every
individual circumstance.
This section contain some additional hints which we hope will help you
further. For further information, please contact your local Keysight
Technologies representative.
Before you make any connection you must ensure that all light-wave
cables and connectors are clean. If not, then use appropriate the cleaning
methods.
When you insert the ferrule of a patch-cord into a connector or an adapter,
ensure that the fiber end does not touch the outside of the mating
connector or adapter. Otherwise, the fiber end will rub up against
something which could scratch it and leave deposits.
Lens cleaning papers
Some special lens cleaning papers are not suitable for cleaning optical
devices like connectors, interfaces, lenses, mirrors and so on. To be
absolutely certain that a cleaning paper is applicable, please ask the
salesperson or the manufacturer.
Immersion oil and other index matching compounds
Do not use immersion oil or other index matching compounds with optical
sensors equipped with recessed lenses. They are liable to dirty the
detector and impair its performance. They may also alter the property of
depiction of your optical device, thus rendering your measurements
inaccurate.
64 Keysight DFB Laser Source Module User’s Guide
Cleaning the housing and the mainframe
When cleaning either the mainframe or the housing of your instrument,
only use a dry and very soft cotton tissue on the surfaces and the numeric
pad.
Never open the instruments as they can be damaged. Opening the
instruments puts you in danger of receiving an electrical shock from your
device, and renders your warranty void.
Cleaning Information 4
Keysight DFB Laser Source Module User’s Guide 65
Keysight 81663A DFB Laser Source Module
User’s Guide
5 Specifications
Architecture of a Plug-in / Sub-Model Concept / 40
SCPI Commands / 41
Executing a SCPI through M8070A SCPI Editor / 43
Keysight 81663A DFB Laser Source Module is produced to the ISO 9001
international quality system standard as part of Keysight’s commitment to
continually increasing customer satisfaction through improved quality
control.
Specifications describe the module’s warranted performance.
Supplementary performance characteristics describe the module’s nonwarranted typical performance. Because of the modular nature of the
instrument, these performance specifications apply to the module rather
than the mainframe unit.
5 Specifications
Definition of Terms
Wavelength tuning range
This section defines terms that are used both in this chapter and
Performance Tests on page 25.
Generally, all specifications apply for the given environmental conditions
and after warm-up time.
Measurement principles are indicated. Alternative, measurement
principles of equal value are also acceptable.
The range of wavelengths for which the specifications apply, where the
relevant center wavelength is defined as the center of the tuning range.
Conditions
At specified conditions and coherence control off.
Measurement
With wavelength meter.
Wavelength display resolution
The smallest possible displayed wavelength increment or decrement.
Wavelength repeatability
The random uncertainty in reproducing the wavelength after detuning and
re- setting the wavelength. The wavelength repeatability is ± half the span
between the maximum and the minimum value of all measured
wavelengths.
Conditions
Uninterrupted DFB laser source module output power, constant power
level, coherence control off, controlled environment as specified.
66 Keysight DFB Laser Source Module User’s Guide
Measurement
NOTE
Wavelength stability
Conditions
Specifications 5
With wavelength meter. Averaging time given by wavelength meter, ≥1 s.
The long-term wavelength repeatability can be obtained by taking the
wavelength repeatability and wavelength stability into account.
The change of wavelength during given time span, expressed as ± half the
span between the maximum and the minimum of all measured
wavelengths.
Uninterrupted DFB laser source module output power, constant
wavelength and power level settings, coherence control off, controlled
environment and time span as specified.
Measurement
With wavelength meter. Averaging time given by wavelength meter ≥1 s.
Max. output power
The highest optical power obtainable at the end of a single-mode fiber
patchcord.
Conditions
At default wavelength.
Measurement
With power meter at the end of a single-mode fiber patchcord.
Keysight DFB Laser Source Module User’s Guide 67
5 Specifications
Power CW stability
The change of the power level during given time span, expressed as ± half
the span (in dB) between the highest and lowest measured power.
Conditions
Uninterrupted DFB laser source module output power, constant
wavelength and power level settings, controlled environment and time
span as specified.
Measurement
With optical power meter.
Sidemode suppression ratio (SMSR)
The ratio of the optical power of the main mode to the optical power of the
highest sidemode expressed in dB.
Conditions
At a specified output power and wavelength, coherence control off.
Measurement
With the optical spectrum analyzer Keysight 81642B, resolution
bandwidth 0.06 nm.
Polarization extinction ratio (PER)
The ratio of optical power in the slow axis of the polarization-maintaining
fiber to optical power in the fast axis.
Measurement
With a polarization analyzer by mechanically stressing the Panda fiber.
Coherence control
Linewidth broadening of optical signal by internal laser modulation.
68 Keysight DFB Laser Source Module User’s Guide
Modulation, digital
Output signal is modulated with 50% duty cycle by internal on / off
switching of the laser current. Switching frequencies as specified.
ON- switching with fast output power stabilization
When the laser is switched on after the specified warm- up time the output
power will settle within the specified time to comply with the power
stability specifications.
Tuning Speed
Maximum time required to change the wavelength of the optical signal
between the extreme ends of the specified wavelength tuning range.
Specifications 5
Keysight DFB Laser Source Module User’s Guide 69
5 Specifications
DFB Source Module Specifications
Specifications apply to maximum power setting after warm- up time.
Table 4
Keysight 81663A
Option #131
Type CW DFB Laser with built-in isolator
Center Wavelength
Tuning Range
Display Resolution
Repeatability
Stability (15min.)
Stability (24h)
Fiber type Panda PMF 9 / 125 μm
Output Connector
Power
Max. Output
CW Stability (15min)
CW Stability (24 h)
Side Mode Suppression Ratio
(SMSR) e
Polarization Extinction Ratio
(PER)
Dimensions (H x W x D) 75 mm H x 32 mm W x 335 mm D (2.8” x 1.3” x 13.2”)
Weight 0.5kg
Recalibration Period 2 year
a b
c
c
c
d
e
c
c
1310 nm ± 5 nm 1490 nm ± 3 nm 1510 nm ± 3 nm 1550 nm ± 3 nm 1625 nm ± 3 nm
typ. > ±500 pm
10 pm
±5 pm (typ. ±2 pm)
± 5 pm (typ ±2 pm)
typ. ±5 pm
Compatible to angled contact APC, ASC, DIN47256/4108
typ. > +13 dBm (20 mW)
typ. ±0.003 dB
typ. ±0.01 dB
typ. 45 dB
typ. > 20 dB
Keysight 81663A
Option #149
Keysight 81663A
Option #151
Keysight 81663A
Option #155
Keysight 81663A
Option #162
Operating Temperature 15°C to 35 °C
Warm-up time
f
60 min
• a- Center wavelength is shown on display as default.
• b- Via GPIB tuning resolution < 10 pm.
• c- Controlled environment DT = ±1 °C.
• d- Connector interface not included.
• e- At maximum power setting and default wavelength at the end of a
2 m SM patchcord.
70 Keysight DFB Laser Source Module User’s Guide
• f- If previously stored at the same temperature 20
Supplementary Performance Characteristics
Internal digital modulation mode: Free selection 200 Hz to 100 kHz.
All output signals are pulse shaped, duty cycle 50%.
Internal variable coherence control for linewidth broadening.
ON- switching with fast output power stabilization <20 s.
Output power “attenuation” at default wavelength 6 dB in steps of 0.1 dB.
Tuning speed over full range 30 s.
Polarization maintaining fiber orientation: TE mode in slow axis, in line with
connector key.
Specifications 5
Keysight DFB Laser Source Module User’s Guide 71
This information is subject to
change without notice.
© Keysight Technologies 2017
Edition 10.0, January 2017
www.keysight.com
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