Indeed it is strange. I took a quick look at it.
In order to recover the same condition (e.g. the same amount of the reflected DC light and the same temperature readout),
it needed to have +8.9V in the slow input from the DAC through EPICS.
Obviously applying an offset in the slow input to maintain the same condition is not good.
It needs another solution to maintain the sweet frequency where the frequency of the PSL and the Y end laser is close in a range of 200 MHz.
Quote from #5797 |
Plugging in the thermal feedback BNC cable to the laser reduced the DC voltage of the green PDH photo diode from 3.12 V to 1.5V off resonance.
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