Reports until 20:08, Tuesday 16 May 2023
H1 SQZ
victoriaa.xu@LIGO.ORG - posted 20:08, Tuesday 16 May 2023 (69677)
Dumping power to not saturate the OPO REFL RF80 PD used for OPO locking

Extreme 1-month late post, but probably worth logging even if late. A month ago on April 16, 2023, I turned down the power on OPO REFL's RF80 PD, to not saturate the refl diode we use for opo locking. I noticed that OPO_REFL_DC_VOLTS was saturated at 10V, (like OPO_REFL_DC_POWER ~ 4.3mW), so I pico-waveplate'd to dump power away from the RF PD, towards OPO_REFL_DC_REJECTED_POWER. At first, the OPO_REFL_RF80_DEMOD_RFMON went up as the optical power decreased (bad/weird), then finally the RFMON went down as the optical power decreased, which I think is expected if we're not saturating the diode.

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