We found that the FSS PC feedback easily goes crazy (saturated).

It was because the common gain was too low. Probably the recent decrease of the

laser power is responsible for this.

We increased the nominal value of the common gain from 12 to 16.5.

The value was chosen just to make the PC path quiet. We should check

the FSS UGF later.

 

The MC WFS QPDs seemed off centered. So we unlocked the MC and lowered

the input power by the usual MZ half fringe technique.

Actually, the direct reflection beam was not much off the center. In anyway, we adjusted

the beam to the exact center of the QPDs.

The MC now locks fine.