As the cavities' height changed, I adjusted the lenses to fine tune the mode matching for RCAV, the visibility is ~85%
We might want to use a bigger beam splitter (the current one is 10mm cube) where the beam split to ACAV and RCAV paths, the spot radius is ~ 3mm. It might cause some diffraction problem.
The next step is to check the beat signal with the previous FSS. We suspect that something might be wrong with the TTFSS. If the old FSS can give us with better signal,
we will use the old one.