Aligning A Pm Fiber Patch Cable - THORLABS ERM200 User Manual

ERM2xx Series Extinction Ratio Meter
a. Go to the Settings View and select ER_min from the Mode parameter.
b. To redetermine the minimum extinction, press the RETURN button after selecting the ERmin
mode. ERmin is updated whenever a lower value is measured.
c. Repeat the procedure while stressing the fiber mechanically or with temperature.
5. The orientation of the PM fiber can be optimized by a trial and error method. Rotate the fiber relat-
ive to the laser diode in one direction, however only slightly and slower than in the crude first ad-
justment (3). The ERmin will be saved. Repeat steps 4b and 4c stepwise, rotating the fiber slightly
and putting it under stress until the ERmin peaks.
Note
The ERM2xx modules cannot distinguish between the fast and slow axis of a PM fiber. A pre-adjust-
ment to the desired main axis is required to align the device under test (DUT) to the slow (or fast) axis
of the PM fiber.

5.7.3 Aligning a PM Fiber Patch Cable

This section describes how to use the ERM2xx module to align a PM fiber patch cable.
For this, Thorlabs recommends using an SLD or ASE as a light source rather than a laser diode.
The Extinction Ratio measurement of a PM fiber with an SLD can be done in the following way:
1. The output connector of the fiber is entered into the fiber adapter on the connection port of the
ERM2xx model and the unit is switched on.
2. Connect the SLD to the input of the fiber bench with the polarizer.
3. Connect the input of the PM fiber to the output of the fiber bench.
Page 16
Chapter 5 Operating Instructions
MTN033660-D02