- Kiwamu, Cheryl

I measured the IO path power budget after turning up the power to 9.1W incident on IO_MB_M2, the beam splitter to the IO path.  This put 1.03W into the ALS path that was blocked with a beam dump, and 8.07W incident on the IO EOM.  Temporary beam splitters are still in the IO path, so power loss there was measured to be 3.65W.

Two ways to calculate the throughput of the IO path - both meet the requirement to deliver at least 75% of power downstream of the PMC to the IFO.

1) Power incident on IO_MB_M2 to power delivered to the IFO:

9.1W - 3.65W (loss due to beam splitters) = 5.45W

4.27W (power after top periscope mirror) / 5.45W (adjusted power incident on IO_MB_M2) = 78% delivered power

2) Power incident on IO EOM to power delivered to the IFO:

9.1W - 1.03W (power in ALS path) - 3.65W (loss due to beam splitters) = 4.42W

4.27W  (power after top periscope mirror) / 4.42W (adjusted power incident on IO EOM) = 97% delivered power