Although the locking accuracy is 1.8Hz with CCFC, the FDS detuning fluctuation is ~10Hz even with CCFC/Z correction/pointing/AA. The possible reasons are parameter estimation error and IR misalignment change and FC macroscopic length change.

sqz_dB = 10.5;                    % 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_L =   1e-12;                  % Lock accuracy (m)

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

Note: In this calculation, shot noise level is assumed to be -133.2 dBVrms/rtHz, but actually it may not be true. So the result in this log could be wrong.