Sheila, Camilla. WP 12116, 12117. Last done in October 2023: 73524.

Followed instructions from 73524, 65684, with additional notes below. 

Took SQZT7 area to local laser hazard and plugged straight into the OPO_IR_PD for our red signal and the OPO_TRANS PD for our green signal. Trying to take the signals from the outside of the table or the SQZ racks was confusing. 

Setup:

• Old style function generator, offset 4.5V for a 1-9V scan at 10Hz.
• Oscilloscope and long BNCs/adapters: plug into function generator, OPO_IR_PD and the OPO_TRANS photodetectors inside SQZT7. 
• PZT driver MDT694 which has 0-150V output for 0-10V input, connected this to the PZT1 connector in the back of the chassis, using the adapter for PZT2 (note this means that the PZT2 offset we had been keeping at +10V was 0V for this measurements, controlled by CLF SLOWOUTOFS 65535). 
• Wincam dell laptop and gray E-870 PI shift driver box (stored in LVEA SQZ cabinet) and the OPO crystal cable remains attached +X HAM7 flange.

What we did:

• After set up once we could see both mode scans on the oscilloscope, we injected the seed beam and reduced green power from 30mW to 6mW to avoid pumping too much. Pico wasn't working: 80449.
• Adjusted temperature to get red and green co-resonance. Plot attached of before spot move. 
• In alog 73524 we used the OPO spot 2nd from the left. We moved (32 x 50 steps to right, then 2 x 10 steps to right) to the next spot with a red-green co-resonance, 3rd from the left. Plot attached.
• Increased the green power back to 25mW, then 30mW and then things got confusing: we were seeing rapidly changing strange signals and negatives on OPO_TRANS channel. Beckhoff version of the channels looked better. We eventually found that the whitening filters must have been saturating and giving us strange signals. We increased SHG ISS drivepoint to 10V, allowing us to use a lower green pump, this showed that the high green pump was our issues. Then reduced the SHG power to 14mW while the SHG ISS drivepoint was in the middle of the range at 5V. When the ISS was engaged, it could keep the opo_grTrans_setpiont_uW to 80uW with the controlmon around 6 and SHG_LAUNCH ~11.5mW. This is much less than the 30mW we needed this morning so this new crystal spot is much less lossy. 
• OPO started to oscillate when we locked it so we reduced the OPO gain from -4 to -8 and accepted in sdf.
• Sheila set the opo_grTrans_setpiont_uW to 80uW in sqzparams.py and we measured the NLG to be 11 (Amplified / Un-amplified = 0.098/0.0089 see 76542).
• Ran SCAN_SQZ_ALGNMENT and SCAN_SQZ_ANG. This gave us >4dB of squeezing at high frequency.  
• We left PZT2 (CLF SLOWOUTOFS) at 0V, see 80450.

Today, 75uW OPO trans power corresponded to 0.945 on the OPO refl diode, last night that was 4.161mW on OPO refl diode. Meaning after this spot move we now need to inject a lot less power into the OPO to get the same output power.