I checked several days data of fringe signals after unplugging the heater output cable. Then amplitude of fringe signals still changes in many times.
Bottom panel of Fig.1 shows that the amplitude still changed after unplugging the heater cable 5 days ago.
In last time, we were able to see the reproducibility of the relation between the heater offset and fringe amplitude.
I'm not sure this result was accidental coincidence or the real relation in a short term. But at least in a long term relation, there seems to be other reason why the amplitude changes.
The fiber output PD on the POP/POS tables are ones of the few non-control signal sensors for green laser systems, so I checked also these signals.
The fiber output power seems to change correlated to the change in fringe amplitude.
Fig.2 shows the fringe amplitude (upper) and the power at POP/POS tables (lower). In both X (left) and Y (right), the correlation can be seen between the fringe amplitude and the laser power at POP/POS.
Does this mean that the change is already occurring at the output laser power from the PSL room, rather than a change in the interference state or the power of return light from the POP/POS tables?
(Fiber coupling in PSL room, output laser power itself from Prometheus, etc.?)
