I analyzed the pole for RCAV and ACAV from 2010_12_06 entry. ACAV has a pole at 54 kHz, RCAV pole is at 38kHz.
Cavity pole = FWHM/2. Knowing cavity pole and FSR, we can calculate a cavity's finesse (= FSR/ pole). These values
will be used when we simulate the TF of the system
We amplitude modulated the laser intensity via EAOM, and measured the TF between RCAV_trans_PD and PMC for RCAV pole.
Since PMC's pole is ~2 MHz and ACAV/RCAV poles should be around 35 MHz, PMC won't effect much on our measurement.
Cavity is 0.2032 m long -> FSR = c/2L = 738 MHz, then
ACAV's Finesse = FSR/FWHM = 6835
RCAV's Finesse = 9710