HP HP 81531A User manual

User's Guide
HP 81531A Sensor Module
SERIAL NUMBERS
This manual applies to all instruments.
ABCDE
HP Part No. 81531-90011
Printed in Germany
Second Edition
E0796

Control Serial Number: Edition 2 applies directly to all instruments.
Edition 1 : 1st May 1990 : 81531-90011 : E0590
1st September 1990 : 81531-90011 : E0990
Edition 2 : 1st September 1991 : 81531-90011 : E0991
1st September 1992 : 81531-90011 : E0992
1st December 1994 : 81531-90011 : E1294
1st July 1996: 81531-90011 : E0796

Safety Considerations
Before operation, you should 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.
Initial Inspection
Inspect the shipping container for damage. If there is damage to the container
or cushioning, you should keep it until you have checked the contents of the
shipment for completeness and veried the module both mechanically and
electrically.
The Performance Tests give procedures for checking the operation of the
module. If the contents are incomplete, mechanical damage or defect is
apparent, or if a moduke does not pass the operator's checks, notify the nearest
Hewlett-Packard oce.
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.).
Power Requirements
The HP 81531A operates when installed into the HP 8153A Optical Multimeter
mainframe.
Operating Environment
The HP 8153A safety information summarizes the HP 81531A operating
environment ranges. In order for the HP 81531A to meet specications, the
operating environment must be within the limits specied in this section.
Input/Output Signals
iii

Caution
A maximum of 15V can be applied as an external voltage to any
BNC connectors.
Storage and Shipment
The module can be stored or shipped at temperatures between
0 40

C and
+70

C. The module should be protected from temperature extremes that may
cause condensation within it.
iv

Contents
C. HP 81531A Specications
Supplementary Performance Characteristics . . . . . . . . . . . C-3
Analog output: .... .. .. .. .. .. .. .. .. .. . C-3
D. Performance Tests
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . D-1
Equipment Required . . . . . . . . . . . . . . . . . . . . . D-1
Test Record .......................... D-2
Test Failure .......................... D-2
Instrument Specication .... .. .. .. .. .. .. .. .. D-2
Performance Test .... .. .. .. .. .. .. .. .. .. . D-3
Accuracy and Linearity Test .... .. .. .. .. .. .. . D-3
Test Setup . . . . . . . . . . . . . . . . . . . . . . . . . D-3
I. Accuracy Test ...................... D-4
II. Linearity Test...................... D-5
III. Noise Test .. .. .. .. .. .. .. .. .. . .. .. . D-8
E. Cleaning Procedures
The Cleaning Kit . . . . . . . . . . . . . . . . . . . . . . . . E-1
Other Cleaning Tools . . . . . . . . . . . . . . . . . . . . . E-3
Preserving Connectors . . . . . . . . . . . . . . . . . . . . . E-4
Cleaning Instrument Housings ................. E-4
Correct Cleaning Procedure .... .. .. .. .. .. .. .. E-5
Cleaning Cable Connectors . . . . . . . . . . . . . . . . . . E-5
Cleaning Connector Adapters . . . . . . . . . . . . . . . . . E-6
Cleaning Connector Interfaces ................ E-6
How to clean instruments with a recessed lens interface . . . . E-7
Light dirt .. .. .. .. .. .. .. .. .. .. . .. .. E-7
Heavy dirt ........................ E-7
Index
Contents-1

Figures
D-1. Accuracy and Linearity Test Setup .............. D-4
D-2. Addition of results (example) . . . . . . . . . . . . . . . . . D-7
Contents-2

C
C
HP 81531A Specications
Specications describe the instrument's warranted performance. Supplementary
performance characteristics describe the instrument's non-warranted typical
performance.
Because of the modular nature of the instrument, these performance
specications apply only to this module.You should insert these pages into the
appropriate section of the manual.
HP 81531A Specications C-1

C
HP 81531A Specications
Sensor Element In GaAs
Wavelength range 800-1700nm
Power range +3 to -90dBm
Display resolution
dBm, dB 0.001
0.0001 on printout
Watt 0.01 to 10
(depending on power range)
Applicable ber type 9/125  m - 100/140  m, NA  0.3
Uncertainty (Accuracy) 6 2.5% (1000-1650nm)
[1]
Total Uncertainty 6 5% 6 1.5pW (1000-1650nm)
[2]
Linearity (0 to -70dBm)
18

Cto28

C const. temp 6 0.015dB 6 1pW
0

Cto55

C const. temp 6 0.05dB 6 1.5pW
Noise < 1.5pW (1200-1600nm)
peak-peak, avg. time 1sec
Dimensions 75mm H, 32mm W, 335mm D (2.8 " 2 1.3 " 2 13.2 " )
Weight net 0.6kg (1.3lbs), shipping 1kg (2.2lbs)
Recalibration period 2 years
Warmup time 20 min.
Information on the traceability of power meters is available on request
[1] at the following reference conditions:
Power level 10  W (-20dBm), Continuous Wave (CW).
Fiber 50  m graded index, NA=0.2, fully excited.
Ambient temperature 23

C 6 5K.
Connector Diamond HMS-10/HP.
At day of calibration (add 0.3% for aging over one year, add 0.6% over
two years).
Spectral width of source < 10nm.
[2] at the following operating conditions:
Fiber  50  m, NA  0.2.
For NA > 0.2 add 1%.
C-2 HP 81531A Specications

C
Ambient temperature 0 to 55

C, non-condensing.
Within 1 year after calibration, add 0.3% for second year.
For Biconic Connector add 6 1%.
Supplementary Performance Characteristics
Add 1% to total uncertainty for the full wavelength range
.
Outside the specied wavelength range, the noise increases by up to 5 times
the value shown above.
Analog output:
Bandwidth:  DC,  300 to 400Hz, depending on range and sensor module.
Output voltage: 0 to 2V into open.
Output impedance: 600 typical.
Max. input voltage: 6 10V.
HP 81531A Specications C-3

D
D
Performance Tests
Introduction
The procedures in this section test the performance of the instrument.
The complete specications to which the HP 81531A is tested are given in
Appendix C. All tests can be performed without access to the interior of the
instrument. The test equipment given corresponds to tests carried out with
Diamond HMS-10/HP conectors.
Equipment Required
Equipment required for the performance test is listed in the table below. Any
equipment which satises the critical specications of the equipment given in
the table, may be substituted for the recommended models.
Instrument/Accessory Recommended Model Required Characteristics
Power Meter Standard HP 8153A Mainframe with Uncertainty
#C01 HP 81533A Optical Head 6 1.5%
Interface Module with
HP 81524A Optical Head
Multimeter Mainframe HP 8153A
CW Laser Sources HP 81552SM and HP 81553SM or Wavelength
HP 81554SM Uncertainty
6 1.5nm
Optical Attenuator HP 8156 Option 101
Connector Adapter (head) HP 81000AA
Connector Interface HP 81000AI 4ea (08154-61701)
Singlemode Fiber HP 81101AC 2ea
Plastic Cap 5040-9351 2ea
Performance Tests D-1

D
Test Record
Results of the performance test may be tabulated on the T
est Record provided
at the end of the test procedures
. It is recommended that you ll out the Test
Record and refer to it while doing the test. Since the test limits and setup
information are printed on the T
est Record for easy reference, the record can
also be used as an abbreviated test procedure (if you are already familiar with
the test procedures). The Test Record can also be used as a permanent record
and may be reproduced without written permission from Hewlett-Packard.
Test Failure
If the HP81531A fails any performance test, return the instrument to the
nearest Hewlett-Packard Sales/Service Oce for repair.
Instrument Specication
Specications are the performance characteristics of the instrument which
are certied. These specications, listed in Appendix C, are the performance
standards or limits against which the HP 81531A can be tested. Appendix C
also lists some supplemental characteristics of the HP 81531A. Supplemental
characteristics should be considered as additional information.
Any changes in the specications 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 specications
supercede any that were previously published.
D-2 Performance Tests

D
Performance Test
The performance test given in this section includes the A
ccuracy Test, the
Linearity Test, and the Noise T
est. Perform each step in the order given, using
the corresponding test equipment.
Note
Make sure that all optical connections of the test setups given
in the procedure are dry and clean. DO NOT USE INDEX
MATCHING OIL.
The optical cables from the laser source to and from the HP
8156A Attenuator to the power meter must be xed on the
table to ensure minimum cable movement during the tests
.
Accuracy and Linearity Test
Specications HP 81531A
Uncertainty : 6 2.8%
y
(1000-1650nm)
Linearity : 6 0.015dB 6 1pW
y
includes aging.
Test Setup
1. Make sure that cable connector, detectors and adapters are clean.
2. Connect the equipment as shown in Figure D-1. Ensure that the cables to
and from the attenuator are xed on the table and that both the optical head
and the DUT are close together so that minimum cable movement is required
when connecting the cable to the head or to the DUT.
Performance Tests D-3

D
Figure D-1. Accuracy and Linearity Test Setup
3. Turn the instruments on, enable the laser source and allow the instruments
to warm up for at least 20 minutes.
Note
The linearity test must only be performed at either 1300nm or
1550nm. The accuracy test must be performed in the -20dBm
range at 10  W at both 1300nm and 1550nm.
I. Accuracy Test
1. On both power meters:
a. Set the calibration factor to zero.
b. Set the wavelength to the wavelength of the laser source.
c. Set the instruments into MEAS mode. Make sure AUTOranging is o and
select the -20dBm range.
d. Set the averaging time to 500ms.
2. Make sure that the HP 8156A output is disabled. ZERO the DUT.
3. Connect the HP 8156A output cable to the standard head and ZERO the
standard meter.
4. Enable the HP 8156A output. Change the HP 8156A attenuation until the
power meter standard displays 10.00  W.
5. Connect the attenuator output cable to the DUT. Check the DUT display and
note the result in the test record.
6. Repeat steps 1 to 5 at the second wavelength with the corresponding source.
D-4 Performance Tests

D
II. Linearity Test
1. Make sure that the HP 8156A output is disabled. ZERO the DUT.
2. Enable the HP 8156A output.
3. On the DUT, switch o autoranging and select the -20dBm range. Set the
display to show results in dBm.
4. Alter the attenuation until the DUT displays -17.4dBm.
5. Press 4
Disp ! Ref
5 , then 4
dB
5 .
6. Press 4
Up
5 to select the -10dBm range.
7. Note the deviation, displayed in dB, as R1 on the test record.
a. In the -10dBm range. Set the display to show results in dBm.
b. Alter the attenuation until the DUT displays -7.4dBm.
c. Press 4
Disp ! Ref
5 , then 4
dB
5 .
d. Select the 0dBm range.
e. Note the deviation, displayed in dB, as R2 on the test record.
8. Repeat the steps a to e at all the range and level settings shown in the test
record.
9. Calculate the non-linearity using the formulae in the test record.
Performance Tests D-5

D
Example Results for the Linearity test
Test Minimum Maximum Measurement
No.Test Description Spec. Result Spec. Uncertainty
II. Linearity Test dB
Range Power (dBm)
-20dBm -17.4 Disp ! Ref
-10dBm 0.004 =R1
-10dBm -7.4 Disp ! Ref
0dBm -0.008 =R2
-20dBm -27.4 Disp ! Ref
-30dBm -0.008 =R3
-30dBm -37.4 Disp ! Ref
-40dBm -0.004 =R4
-40dBm -47.4 Disp ! Ref
-50dBm 0.02 =R5
D-6 Performance Tests

D
Example Calculated Results for the Linearity Test
Test Minimum Maximum Measurement
No.Test Description Spec. Result Spec. Uncertainty
Non-Linearity
Range Formula
0dBm R1+R2 -0.015dB -0.004 dB +0.015dB 6 0.006dB
-10dBm R1 -0.015dB 0.004 dB +0.015dB 6 0.006dB
-20dBm 0.000dB 6 0.00dB
-30dBm R3 -0.015dB -0.008 dB +0.015dB 6 0.006dB
-40dBm R3+R4 -0.015dB -0.012 dB +0.015dB 6 0.008dB
-50dBm R3+R4+R5 -0.015dB 0.008 dB +0.015dB 6 0.010dB
Shown graphically, these results look as shown in the following gure:
Figure D-2. Addition of results (example)
Performance Tests D-7

D
III. Noise Test
Note
The noise measurement must be performed with either a
module or a blank panel in the second channel position.
Connect the equipment as shown in Figure D-1.
Disable the HP 8156A output.
On the DUT, select AUTOranging, and display in Watts. Set the averaging time
to 1s.
Press 4
Zero
5 .
Select the MENU mode.
Press 4
Record
5 , to select Stability .
Press 4
Edit
5 and select the T_TOTAL parameter. Set T_TOTAL to 1 minute.
Press 4
Edit
5 , and then 4
Exec
5 to run the noise measurement.
When the test has completed, press 4
More
5 to select the SHOW application. Press
4
Edit
5 and then 4
Next
5 / 4
Prev
5 to display the DIFF result.
Note the DIFF result as the noise value in the test record.
D-8 Performance Tests

D
Performance Test for the HP 81531A
Page 1 of 4
Test Facility:
Report No.
Date
Customer
Tested By
Model HP81531A Sensor Module
Serial No. Ambient temperature

C
Options Relative humidity %
Firmware Rev. Line frequency Hz
Special Notes:
Performance Tests D-9

D
Performance Test for the HP 81531A
Page 2 of 4
Test Equipment Used:
Description Model No. Trace No. Cal. Due Date
1. Lightwave Multimeter (Std.) HP 8153A
2. Opt. Head Interface Module HP 81533A
3. Optical Head HP 81524A
4a1. CW Laser Source HP 81552SM
4a2. CW Laser Source HP 81553SM
4b. CW Laser Source HP 81554SM
5. Optical Attenuator HP 8156A
Opt.101
6. Lightwave Multimeter (DUT) HP 8153A
7. Connector Interface HP 81000AI N/A N/A
8. Connector Adapter HP 81000AA N/A N/A
9. Singlemode Fiber (2ea) HP 81101AC N/A N/A
12.
13.
14.
15.
16.
17.
18.
D-10 Performance Tests