Following the measurement of the power recycling gain (alog 14532), I made an estimation of round trip loss in the power recycling cavity.

In order to explain the recycling gan of 21 for the 45 MHz sidebands, round trip loss needs to be 2.3%.

The plot shown above is power recycling gain for the 45 MHz sidebands as a function of round trip loss. The blue curve represents the one without losses but with the effect of the Schnupp asymmetry. The green one is that with all the known losses included.

For more details, see the attached python code. Also, the highest gain we can achieve is 42 for the 45 MHz without round trip losses. Note that I assumed both ITMs to have the same curvature and also I have not included the mode matching effect.