Aritomi, Eleonora, Yao-Chin, and Yuhang
We summarized the loss budget in the first attached figure.
From the power measurement as following, we could know this part contributes about 10% of loss
| measured after first PBS after OPO | 265uW |
| measured after last mirror before PR chamber | 198uW |
From the power measurement as following, we could know this part contributes about 1% of loss
| measurement of IR reflection after PR chamber | 221uW |
| measured before homodyne | 218uW |
We also measured the IR reflection(IR_ref) beam shape as in the attached figure 2. It has a bit ellipse in the horizontal direction. Because of this elongation, we had a second order peak when we match this IR_ref to alignment mode cleaner(as shown in the attached figure 3,4). By comparing this higher-order peak(12mV) and TEM00 peak(276mV), we could deduce the homodyne readout efficiency should be (1-12/276)^2 = 91.5%. But this IR_ref has beam jittering, so the real readout efficiency should be less than 91.5%.
We also measured the filter cavity round trip loss again. By using the same method we used last year, we found now this value is around 100ppm. We will do more investigation to make sure of this. The measurement is attached in the figure 5.
In the last figure, the achievable squeezing without considering phase noise is attached.
