[Aritomi, Yuhang]
We measured loss from PBS after OPO to filter cavity reflection just after PR chamber. We haven't measured loss from filter cavity reflection to homodyne yet.
position | BAB power (uW) |
after PBS | 273 |
after faraday on the bench | 254 |
after HWP | 248 |
before PR chamber | 242 |
after PR chamber | 211.5 |
From this measurement, loss from PBS after OPO to filter cavity reflection is 22.5%. Since we know that loss when squeezed light is directly injected to homodyne is 21%, total loss should be at least 40%.
We found that HWP we were using before had 5% loss and seems dirty. This explains 4% additional loss when I did additional loss measurement using this HWP. After replacing with new one, HWP loss becomes 2.4%.
Faraday on the bench has 7% loss. Alignment of the faraday should be optimized.