Marc, Michael and Yuhang

In september, we had problem of FDS measurement, which is the FDS feature (rotation from sqz(asqz) to asqz(sqz)) disappeared when we locked CCFC loop. After that, it has been long time we didn't measure FDS again. Recently, we would like to change the FDS configuration. So we decide to redo the FDS measurement before going on. The important degradation sources are as following:

Green power: 25mW (11dB generated squeezing)

optical losses: 68%

CC2 loop introduced a 30dB attenuator for error signal (We found CC2 loop always had oscillation & CC2 loop could be only closed when the gain is small)

other parameters are kept the same with setting in this Feb. Besides, detuning was chosen to be 114Hz (this number is calculated from entry 2296)

The measurement was sometimes not stable today. This instability was the squeezing level going up and down for each measurement. However, this happened while CC1 and CC2 loop were both locked(a bit strange for me, we could check those spectrums). Anyway, we found some stable moments and took measurement.

According to the mentioned degradation sources, I tried to fit data and got results in attached figure 1. The detuning was fit to a larger detuning compared with setting. Besides, the fit curves don't match well with data. However, the good point is that FDS could be measured again with CCFC loop closed.