Summary of data from polarization tests, 4/17/12.

I took multiple sets of data with an OZ Optics polarization scrambler in two positions in the fiber system. Position one is just after the laser diode, position two is just before either the rotator mirror or Au-tipped fiber.

These measurements were for scrambler settings of either 0-4 V or 0-5 V on scrambler channel one (in steps of either 1V or 0.1V). The response was measured at the end of the fiber system (commonly referred to as "loop 3"). Both configurations for the position two data sets had phase offsets that were not corrected in this initial analysis. The phase response was essentially periodic with a period less than 0-4 V, so I've not distinguished between the two here.

Plots: (note, these are out of order: Acrobat's fault? They are also not the best titles: My fault)

Images of Coupled Channels

In addition to the measurements above, I recorded images of the coupler output for 1hz sine wave modulation of channel one of the scrambler (converted to phase signals). These are primarily for the sake of discussion. Magnitudes of the signals were on the same rough scale, though it is hard to pull anything from these without re-timing the whole system, each time, which is expensive. The one thing I'm trying to make sense of is the change from picture one to two. Both are position two (at the end of the system). Picture one is with the gold fiber, picture two with the Faraday Rotator Mirror.
 

Additional Notes

* After transporting and putting the system back together in 685, and then recovering from the power outage, power delivered to the photodetectors seems to be high. Gain was reduced on loops 1 and 3.* Gain on loop 1 BJT amp now at 10* Gain on loop 3 Analog Modules amp adjusted to match previous calibration