Output Isolation; Polarization Extinction Ratio - Keysight 81940A User Manual

Output isolation

Polarization extinction ratio

Keysight 81940A, 44A, 49A, 80A & 89A Compact TLS Modules User's Guide
The insertion loss of the built-in isolator in the backward direction.
Measurement:
This characteristic cannot be measured from outside the module. It is
based on known isolator characteristics.
The 81944A compact tunable laser source has a built-in polarization
NOTE
controller which alters the polarization of the output.
The information here about the polarization extinction ratio does not
apply to the 81944A.
Specifies the ratio of the optical power in the slow axis of a connected
polarization-maintaining fiber to optical power in the fast axis, expressed
in dB.
Cond itions:
Applicable to tunable laser sources utilizing polarization maintaining fiber
that has its TE mode in the slow axis and aligned with the connector key.
Measurement:
Using a polarization analyzer at the end of a polarization-maintaining
patchcord, by sweeping the wavelength to create circular traces on the
Poincaré sphere. Calculate the polarization extinction ratio from the
diameters of these circles.
Specifications 3
37