Daniel, Nutsinee

Attached an LO IMON (in-loop) before and after we removed the feed forward that we plugged back in the night we injected squeezing the first time (Dec 10). Since our configuration makes the laser follows the OPO, any left over noise that LO have to deal with would be the OPO length noise and turned out the feed forward set up (going from ADC through a pomona box to in-vac PZT driver) introduced a lot of OPO length noise. The rms at low frequency came down from 100mrad to 10 mrad after the cable was unplugged. Daniel reconfigure the loop shape that puts us below 10 mrad (3rd attachment, 30kHz UGF). The 1.4kHz peak now dropped by a factor of 6. The 1.4kHz wasn't improved after we unplugged the feed forward cable. It disappeared from TTFSS PZT mon when LO loop was engaged and came back when LO loop was disengaged (our LO loop feeds back to the OPO PZT). This suggests that 1.4kHz may have come from the OPO itself. 

Part of the noise >25kHz can be made better or worse by adjusting sqz angle phase. So the gain has to be reconfigured for the squeeze angle phase when we know where to leave them.