Attached figure 1 is a characterization of laser current dependent beam size measurement. The measurement is done at a point shown in the attached figure 2.

There was two abrupt beam parameter change points. They coincides with the change of half wave plate before Faraday isolator, which is used to reduce laser power going to the beam profiler. It seems that there is also depdence of the measured beam size on this half wave plate. Or maybe the measurement depends on the laser power going to the beam profiler. A slightly more investigation would be better.

The half wate plate angle was originally 38 degrees.