I dived into the alog to make the OLTFs in the MC_controls example more realistic. I was mainly inspired by these entries:
https://alog.ligo-la.caltech.edu/aLOG/uploads/47116_20190708131007_carmolg_20190702.png
https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=18742
https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=20466
and Evan's and Dennis's Theses.
Attachment 1 shows the new OLTFs. I tried to make them go like 1/f around the UGF and fall as quickly as possible at higher frequencies. I didn't do more advanced stability checks.
I also noticed that imbalances and detunings in the MC simulation can change the plants significantly. Especially DARM, CARM, and sometimes PRCL. I added the option to fix some OLTFs throughout the simulation. At every iteration, the simulation computes the required control filter to fix the selected OLTFs such that it will match the OLTFs in the undetuned and balanced IFO.
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