I am experimenting in trying to manually multiply the all the Kappas and set the cavity pole as at the time of measurement on 20200113, as is being discussed in the last two comments in this aLOG thread.
I used ndscope to acquire Kappas for: UIM, PUM, TST, Optical Gain, and Cavity Pole (not really Kappa, just altered the actual value to the one at time of measurement).
Attached here are two plots:
- The first, is where I have taken the response ratio at the time of the measurement and divided it by the underlying model. - You can see some of the wobbles are well described, but there is something going very wrong.
- The second is where I have manually reduced Kappa_PUM to something like 1.005, instead of 1.017. From fiddling with the numbers I came to realise that it is the Kappa_PUM that impacts the frequencies that look way off in the first plot - hence this alteration.
I am beginning to suspect that the estimate of the Kappa_PUM might be grossly exaggerated? Perhaps the frequency where it is being sensed is not a great choice?
Jeff is currently working hard to get a better figure for the actuation force coefficients. However if what I am suggesting above is true: if he improves the actuation force coefficient for the PUM stage, then the Kappa_PUM would change by the magnitude of the change he makes. At the end of the line, after applying Kappas there would actually be no change at all, and this problem would perpetuate.