[Aritomi, Yuhang]

First we measured dark noise of homodyne since we had large 50Hz noise in shot noise spectrum. The dark noise already had large 50Hz noise and we found that when we removed ground floating of spectrum analyzer we are using, these peaks disappeared (Pic 1).

For CC, we checked noise in SHG, GRMC (entry 1514). Then we tried to lock CC1 and 2. For CC1, at the beginning of today we could lock CC1 in stable region between 500Hz and 7kHz resonance, but at the end of today, we couldn't find stable region somehow. For CC2, we couldn't lock it stably so we put rubber to CC2 mirror holder and 4kHz peak is damped (entry 1508), but we still cannot lock it because of 7kHz resonance. 4kHz resonance should be resonance of mirror holder, but we don't know where 7kHz resonance comes from.

Then we measured squeezing with 50mW green (Pic 2) when both CC loops are stable. Squeezing is ~5dB and anti-squeezing is ~20dB. Squeezing spectrum was not very good due to phase noise. We also measured it with 40mW green (OPO:7.169kOhm, PLL:150MHz). Squeezing spectrum is more clear while squeezing level is almost same.