Naoki, Dhruva, Nutsinee

We recovered the homodyne and got 6.5dB squeezing with PMC and 40 times more CLF power as shown in the attached figure.

First we aligned LO and seed to homodyne. We got 97% visibility in SQZT7, but we have not done fine tuning of ZM alignment and PSAMS. We will do it tomorrow. To lock the homodyne LO, we reverted the cabling for SQZ angle dither lock in 74223. We unplugged the "ISC_SQ_96" cable from IN2 of LO CMB and plugged the "ISC_SQ_232" cable.

Then we optimized the OPO temperature. NLG is 16.7 with nominal 80uW of OPO trans. After optimization of NLG, we got 6.5dB squeezing. The CLF6 RFMON is 6, while it was -26 during O4a so we have 32dB = 40 times more CLF power. We measured the CLF power just before the fiber and it is 0.7mW. The CLF_LAUNCH_DC_POWERMON is calibrated to this value.

We increased CLF CMB gain from -8dB to 0dB to reduce the noise around 1kHz. We still have the noise around 1kHz, but it could be further reduced by tuning CLF/LO gain and reducing the CLF power.