Figure 1 shows a violin mode in B1 (OMCs transmission) and in B1s1 (OMCs reflection) before (purple) and after (blue) an alignment adjustment that improved the ITF optical gain by ~4%.
B1s1 sees ~7% of the reflected light and B1 PD1 50% of the transmitted light. So the heights of the lines corresponds to
33e-6/7e-2/0.00142/2 = 16.5% of reflected carrier light before alignment improvement
26e-6/7e-2/0.00142/2 = 13% of reflected carrier light after alignment improvement
If this is really true it would imply there is lots of light rejected by the OMCs for a different reason than alignment. A possible explanation is that the mode matching tuning done on the single bounce beam is not representative of the ITF beam size when the ITF is hot. To be further investigated.
