7/25

[Chien-Ming, Hsun-Chung, Marc, Michael]

We realign the P-pol and BAB by using the steering mirrors before PBS

p-pol :

Before: TEM00=1.78V; hom=460mV+100mV ; 76% mode-matching
After: TEM00=1.92V; hom=160mV+160mV ; 85.7% mode-matching

BAB :
Before:  TEM00=1.05V; hom=264mV+200mV+180mV+140mV+50mV=834mV ; 55.7% mode-matching

After:  TEM00=1.17V; hom=232mV+200mV+200mV+140mV+50mV=822mV ; 58.7% mode-matching

To check the green pump to OPO alignment, we use BAB to optimize the nonlinear gain.
Without green, we phase lock the p-pol at 270MHz and tune the OPO temp. from 7.147 to 7.123.

we obtain the maximum BAB output by putting the power meter before homodyne BS.

The value is 1.78V - 900mV(background) =  880mV (however, power meter is set at 532nm)

When we want to introduce the green pump, we failed to lock GRMC and MZ, also the SHG output is not good.

So I realign the SHG input 1064nm beam,
Before:TEM00=1.58V; hom=1.28V; 55.2% mode-matching
After:TEM00= 354mV; hom:10mV; 97.3% mode-matching

Then I check the PDH signal of SHG and optimize it by changing the phase from 110 degrees to 160 degrees.

I successfully locked SHG. The power in front of MZ is 132.6 mW.

Then I check the PDH signal of GRMC, it's quite small, the S/N=280mV/50mV ~ 280mV/100mV.

Optimizing this signal by adjusting the mirror at the GRMC input reflected beam and then reloading the DDS2 to change the phase of GRMC demod. from 165 degrees to 100 degrees. We obtain the S/N= 126mV/15mV.

Finally, we successfully locked GRMC after adjusting the parameters of the servo.

After locking the MZ, the pump power corresponding to the MZ offset is as follows: