Performance Tests
Performance Tests
Agilent 81618A/9A and Agilent 81622B/3B/4B/6B/7B/8B User’s Guide, Second Edition
41
Performance Tests
The performance tests given in this section includes the Accuracy
Test, the Linearity Test, the Return Loss Test (for the
81622B/23B/26B/ and 27B) and the Noise Test. The performance tests
for the Agilent 81624B/6B also include – as optional tests – the
Relative Polarization Uncertainty and the Relative Interference
Uncertainty Test. Perform each step in the order given, using the
corresponding test equipment.
N O T E
Make sure that all optical connections are dry and clean. DO NOT USE
INDEX MATCHING OIL. For cleaning, use the cleaning instructions
given in
“Cleaning Information” on page 87
.
The optical cables from the laser source to the 8156A Attenuator and
from there to the power meter must be fixed to the table to ensure
minimum cable movement during the tests.
NOTE
For 81628B only
The performance test for the 81628B High Power Head does not differ
from the test procedure for an optical head without an integrating
sphere, except for the linearity test. The integrating sphere of the
81628B has to be disconnected for testing the linearity of the head
alone. A special adapter and a disconnecting tool are necessary for
disconnection. These tools are included in the Performance Test Kit
(order P/N 81628-68705).
If the integrating sphere is disconnected the performance of the
81628B has to be verified. If performing a performance test on the
81628B that includes the linearity test, it is necessary to start the
procedure with the linearity test and then perform the accuracy and
noise tests afterwards.
The non-linearity of the 81628B is not normally tested up to the
specified power level of +38 dBm. The linearity test only verifies the
linearity of the head without the integrating sphere up to 10 dBm
(equivalent to 40 dBm with the integrating sphere). The attenuation of
the integrating sphere is typically 31
±
1 dB, hence the maximum input
power for the photodiode is in the range 6 - 8 dBm and so the test
described below covers this input power range of the photodiode. The
contribution of the sphere to the non-linearity is caused by the heating
of the sphere due to applied power > 30 dBm. These linearity
characteristics are determined by sample testing of the 81628B in
OCMD’s metrology lab.