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Ensuring accuracy of
low-level re
ections
Polarization balance calibration: the inside story
The receiver contains a polarization splitter that splits any incoming light into two orthogonal
polarizations. (Refer to \Block Diagram" in Chapter 5 for a block diagram of the instrument.) A
photodiode mixes the optical elds re
ected from the two arms of the interferometer and generates
the interference signal in each polarization. To ensure proper operation of the receiver, the reference
arm re
ections needs to be about equally split between the two polarizations. The balance receiver
calibration ensures that this condition is met.
During balance receiver calibration, the
termination. This means substantially that the only light that hits both receiver detector diodes is from
the mirror in the reference light path. The polarization of this light is then adjusted by the front panel
reference polarization balance knobs such that the responses from each detector are equal, or balanced.
Subsequent measurements of polarization-independent return loss are then insensitive to polarization
transformations of the ber in the test arm.
All manuals and user guides at all-guides.com
dB
Log :
: dB
Performing Guided Setups and Calibrations
Performing Manual Calibrations
Log :
TEST PORT
cable is terminated with a low re
ection
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