R&D (FilterCavity)
NaokiAritomi - 21:10, Thursday 27 May 2021 (2537)
100Hz bump was removed

[Aritomi, Yuhang, Michael]

Today we found that the SMA cable for GRMC demod was not fixed well. After we fixed it, the 100Hz bump disappeared!

The attached figure shows FDS with CCFC. CCFC gain was 2000 and CC2 mass feedback gain was 2.7. Although the 100Hz bump disappeared, there is still a small bump at 150Hz and many 50Hz harmonics. We might have another unfixed cables.

The detuning is a bit high in this measurement so we will measure FDS with correct detuning again.

sqz_dB = 10.4;                    % produced SQZ (dB)

L_rt = 120e-6;                    % FC losses

L_inj = 0.31;                     % Injection losses  

L_ro = 0.24;                      % Readout losses

A0 = 0.05;                         % Squeezed field/filter cavity mode mismatch

C0 = 0.05;                         % Squeezed field/local oscillator mode mismatch

ERR_csi = 30e-3;                  % Phase noise (rad)

ERR_L =   1e-12;                  % Lock accuracy (m)

Images attached to this report
2537_20210527190137_20210527ccfcfds.png