Vicky, Dhruva We aligned and swapped the SK and FCGS paths compared to https://dcc.ligo.org/D2000242-v1. The PD cables were swapped accordingly and the entire motorised waveplate assembly was swapped too. The entire FCGS REFL path is now nearer the door for easier access. We also installed FC_BEAT_RF1, as a PDA100A2 as speciffied in T1600605. S/N: TP02010820
SK path seems to be working; when setting the 2nd FC AOM2 VCO to +80.000100 MHz (while FC AOM1 set to -80MHz), we see phase noise on the FC BEAT note around 100 Hz. Makes sense, this path beats FC_REFL vs OPO_GR_REFL, both of which are ~at the SHG frequency. Beatnote can probably be optimized with in-vac picos, and clipping reduced by dropped the perioscope mirror as Camilla notes (64680).
Also calibrated FC_BEAT_REJECTED and FC_REFL_REJECTED photodetectors, saved to SDF.