Laser temperature settings for Y arm green work today are;
PSL laser temperature on display: 31.38 deg C (PSL HEPA 100%)
C1:PSL-FSS_SLOWDC = 1.68
Y end laser "T+": 34.049 deg C
Y end laser "ADJ": 0
Y end laser measured temperature: 34.13 deg C (*)
C1:GCY-SLOW_SERVO2_OFFSET = 29845
Green transmission from Y end and PSL green power on the beat PD are;
P_Y = 28 uW
P_PSL = 96 uW
P_Y decrease from its maximum we got (75 uW, see elog #6777) is because the alignment for Y arm green is decreased. I can see the decrease from the green reflection on ETMT camera, but I will leave it because we already have enough beat.
I aligned PSL optics, including the mode-matching lens to maximize the beat note. The beat note I got is about 26dBm.
The calculated value is -14 dBm, so we have about 75 % loss.
I measured the reflection from the PD window and its reflectivity was about 30%. We still have unknown 45% loss. |