[Chien-Ming, Hsun-Chung]
To check the alignment of green pump to OPO, we measure the nonlinear gain of BAB maximum in 1st HOM PD.
without green, Max=248mV (forgot to subtract the background); p-pol PLL 270MHz; OPO T:7.127
with 25.1mW green, Max=1540mV (Min=120mV) (also forgot to subtract the background) ; p-pol PLL 190MHz; OPO T:7.129
after two hours..
with 25.1mW green, Max=1200mV (Min=120mV) ;OPO T:7.129
I realign the green to OPO and adjust temp. of OPO
with 25.1mW green, Max=1580mV (Min=120mV) ;OPO T:7.123
without green, Max=248mV; OPO T:7.122
| green power (mW) | 0mW | 25.1mW |
| OPO temperature (kOhm) | 7.122 | 7.123 |
| p pol PLL frequency (MHz) | 270 | 190 |
| BAB maximum (mV) | 248* | 1580* |
| nonlinear gain | 1 | 6.37 |
*This value does not check and subtract the background caused by p-pol.
To optimize HOM visibility, we realign the OPO output BAB mode matching at AMC.
Before: TEM00=164mV; hom=34mV+8mV+8mV ; 76.6% mode-matching
After: TEM00=218mV; hom=8mV+8mV ; 93.2% mode-matching
Realign the IRMC mode matching by monitoring the T of IRMC servo
Before: TEM00=920mV; hom=48mV+48mV; 90.6% mode-matching
After: TEM00=960mV; hom=56mV; 94.5% mode-matching
IRMC PDH signal and SHG PDH signal are using the same DDS channel to demodulate, so readjust the DDS phase from 110 to 140 degrees to reach a compromise. (Used 160 degrees to reach the best SHG PDH signal yesterday)
LO mode matching at AMC
TEM00=6.64V; hom=16mV ; 99.76% mode-matching
GRMC failed to lock again, checking the PDH signal and reloading the DDS2 to change the phase of GRMC demod. from 165 degrees to 200 degrees (Used 100 degrees yesterday).