[Aritomi, Yuhang, Marco, Matteo]

 

First we swapped PDs for IRMC reflection and OPO reflection because the PD for IRMC had better responsivity and should be good to get error signal of coherent control. PDs we have now are shown in attached pictures.

 

With that PD, we locked IRMC. Filter parameter is

Filter: gain 1, 30Hz lowpass, no attenuation

 

Then we aligned LO to AMC again. The peak height was 8.24 V and mismatch peak was 16 mV, which means mode matching is 8.24/(8.24+0.016) = 99.8%.

 

Since we don't have BAB now, we used CC for alignment to AMC. We locked CC PLL at 7 MHz and p pol PLL at 207 MHz as usual and aligned CC to AMC. The peak height was 80.8 mV and mismatching peak was 5.4 mV, which means mode matching is 80.8/(80.8+5.4) = 93.7%. This value is almost same as before.

 

Then we replaced the flipping mirror before homodyne. Attached picture shows new magnetic flipping mirror. Alignment of this mirror is not done yet.

 

Next step:

-first, replace the flipping mirror which has a long micrometer and align CC to AMC again

-align flipping mirror before homodyne

-check shot noise and squeezing again

-check homodyne RF signal and get error signal for phase locking of CC and LO