7/27 [Chien-Ming, Hsun-Chung]
Summary:
We measured about 5 dB squeezing and 11 dB anti-squeezing at 25.1mW pump power.
Current parameter settings:
| DDS1 | ch1 | SHG & IRMC demod. | phase 140 deg. |
| DDS2 | ch2 | GRMC demod. | phase 200 deg. |
| DDS3 | ch3 | P-Pol PLL |
54MHz (0 mW green) 38MHz (25 mW green) |
| DDS3 | ch1 | homodyne phase |
SQ: 75 deg ASQ:140 deg |
Details:
| ch1 |
| ch1 |
CC light is not coupled into the OPO at all, after realignment
CC: TEM00=19.8mV; hom= 4.6mV+2.2mV; mode-matching: 74.4%.
SHG output power dropped to half, so we realign the incident 1064nm again, and now the green power before MZ is 126.7mW.
When the green light is well coupled into OPO, the GRMC and MZ are not easy to be locked. Seems to be interference from the feedback light.
When put the LO flip mirror back, the LO light is not coupled into the 2nd HOM PD at all.(but it worked yesterday)
We have to adjust the lens position to achieve HOM DC balance.
The BAB nonlinear gain today without green and with 25.1mW green again: (this time we have considered the background by blocking the BAB.)
without green, Max=240mV-6mV(BG)= 234mV ; OPO T:7.117
with 25.1mW green, Max=1390mV (Min=96mV) ;OPO T:7.119
|
SQ: 75 deg ASQ:140 deg |
| Pump power (mW) | 0mW | 25.1mW |
| OPO temperature (kOhm) | 7.117 | 7.119 |
| P-Pol PLL frequency (MHz) | 270 | 190 |
| BAB maximum (mV) | 234 | 1390 |
| nonlinear gain | 1 | 5.94 |
|
SQ: 75 deg ASQ:140 deg |
cc1 cc2 can be locked smoothly.
cc1 error signal EPS1OUT Vpp=266mV.
cc2 error signal EPS1OUT drifts up and down over time in the range of 348mV, the Vpp is around 170mV.
The parameters we use for SR785 are:
128Hz~102.4kHz AC
FFT1 LogMag Hanning
Compute Avgs: Yes; type: Exp./cont; # Avgs: 100 ; Display Avg: RMS
SAVE: Display to Disk
|
SQ: 75 deg ASQ:140 deg |
|
SQ: 75 deg ASQ:140 degS |
