Aritomi and Yuhang
Green injection power to filter cavity: 12mW
Green reflection power from the filter cavity (measured from the FI extraction point)(filter cavity unlock): 5mW (we loss a lot)
This reflection is separated into two parts:
1. To FC lock PD: 3.5mW(FC unlock) 2.3mW(FC lock)
2. To auto-alignment: 0.9mW(FC unlock) 0.6mW(FC lock)
Notice: the green power was measured with a power meter and it fluctuates a lot. So the number reported above is value roughly located in the middle of this fluctuation range.
So the BS is splitting reflection with ratio 20:80 (R:T). Also there is a ghost beam and it is roughly 0.1mW. It would be nice that we can have a 90:10 BS to replace. Because we only need less than 0.3mW for filter cavity lock.