Using the data taken yesterday's lock of X arm, the external disturbance of this loop, (which is dominated by frequency fluctuation of main laser at f >~1 Hz), are quickly plotted here along with the estimated frequency noise of IMC transmission.

NOTE:
-- This estimation of IOO frequency noise was done for the Phase-1 configuration, which is different from current one. So these two traces cannot be compared directly.
-- No precise fitting for OLTF has not yet been done. The OLTF of CARM loop was modelled just using the measured unitiy gain frequency of ~2.5kHz (at this moment, IN1 gain was not 31dB, but 26dB. So UGF was not 5kHz, but 2.5kHz).