From 23-12-26

Yuhang, Michael

Apparently there was some issue with the connection of rampeauto to main laser (filter cavity servo). This was turned off and CC PLL improved, but the issue is still delayed into the future.

The current situation with the CC PLL is that the cable from the slow loop correction of the servo to the CC laser wasn't working, so we improvised and it's dangling over the optical table. This will need to be fixed at some point. The issue with the 2V required/200 mV provided correction signal was due to the sideband being on the wrong side of resonance. We should be such that decreaing the temperature of the laser decreases the frequency of the peak on the spectrum analyzer, and then position the peak about 20-30 MHz away from resonance before turning on the loop. This is a strange issue of the CC PLL system where somehow the correction signal has some offset and only properly corrects for sidebands initially far enough away from resonance.

We wanted to test taking the data for the Taiwan machine learning measurement. We injected to CC2 Ramp IN but it showed little if no effect on homodyne. In the electrical diagram EPS1 and Perturb IN add to give EPS2 so we just decided to add it at Perturb IN. Then we can see what looks like squeezing and antisqueezing on the homodyne. However, the maximum voltage sent to Perturb IN while CC2 is locked is quite low, only up to about 10 mV. Still, it seems to work, so we should verify squeezing and antisqueezing level over the scan range using the DGS system.