This is a repetition of Valera's projection for how we expect the DARM spectrum to behave as we increase the laser power. The current (23 W) quantum noise estimate from GWINC was subtracted from the DARM spectrum and replaced with a set of higher-power quantum noise curves. For reference, I've also plotted the null stream and the sum/null residual. This is from 2015-09-12 06:30:00 Z.
This projection assumes, of course, that nothing else about the ISC changes. Also, I suspect that the range estimates are slightly higher than what we're used to because these spectra are median-averaged. Dan has already showed that our bucket noise is not Rayleigh distributed, so we expect the median spectral estimate to be lower than the mean estimate at these frequencies. I briefly compared a mean-estimated spectrum (from the frontend calibrated DARM channel, and from the same time) and got an inpsiral range of 75 Mpc for the 23 W spectrum.
Anyway, the message is that with our current correlated noises, we only win about 30 % more range with a factor of 5 more laser power.
Interesting result. It says that to improve detection sensitivity for both NS/NS and BH/BH binary coalescences we need to find out why we have excess noise in the 40 to 150Hz band. Neither increased power nor squeezing will help significantly in the detection threshold though they will help in providing more science once detections have been made.