Sheila, Jennie, Camilla. Last done in 76040. Want to get a homodyne measurement in our new OPO crystal spot location 82134, would plan to then repeat this a few months later to see any difference.

Aligned the homodyne but ran out of time before taking any data. May try to repeat on Thursday during commissioning.

Sheila offloaded the IFO ASC and edited the guardian code for clearing the ASC so that it now includes clearing the integrators that we moved into the ZMs.

Turned up SEED injected power from 0.7mW to 72mW to match the power from the LO (0.544mW on HDA and B). We later turned the LO power down with the pico HWP to match the SEED power.

Jennie adjusted the LO beam with SEED beam blocked to improve the subtraction: Checked we were centered on PDA/B using the steering mirrors downstream of the HD BS and then measured the HD DIFF spectrum. Adjusted BS, re centered on HD PDs and re-checked if DIFF spectrum shot noise had improved.

Sheila and Jennie aligned the SEED beam onto the LO beam. We expected to be able to see fringing on HD A/B at this point but couldn't, tried adjusting the alignment with ZM4, didn't help. It turned out tat the fringing was there, clear when using an oscilloscope just unclear on ndscope. Sheila further tuned the SEED alignment to minimize fringing. We measured peaks at 1.85V, bottom of fringes at 29mV with 2mV dark noise, giving visibility of 97.1%.

Then went back to the control room and measured NLG like normal (OPO to LOCKED SEED NLG), NLG = 10.3. Sheila turned down the SEED beam back to 0.7mW. 

Then could start to take HD SQZ measurements, Using SQZ_MANAGER to SQZ READY HD (takes LO to LOCKED HD) and OPO to LOCKED_CLF_DUAL. We needed to increase SHG power from 10mW to ~16mW to allow 80uW on OPO Trans.

Plot attached: Dark noise was the same as original plot, LO shot noise (ref10), With NLG 10.3,  ASQZ was 13.8dB (ref2), this seems similar to last measurements.

We planned to take ASQZ/SQZ data at different NLG's, however I was having some issues with the OPO GRD unlocking and ran out of time. May continue on Thursday during commissioning time.