daniel.sigg@LIGO.ORG - posted 10:32, Thursday 31 October 2019 - last comment - 15:40, Thursday 31 October 2019(52832)
OPO length noise
Nutsinee, Daniel
When we remeasured the OPO length noise, we noticed that the second of our two peaks at 1 and 1.4kHz was gone. We traced this back to the maintenance day on 4/9/2019.
During this Tuesday we changed the laser current (alog 48361) and replaced a few pieces of electronics (alog 48353). At this point, I suspect the PZT driver.
Attached the quick OPO in-loop measurement from January and now (October). Not sure what's going on with the overall higher noise. It's likely that I don't know the old calibration all that well.