In the past days I have implemented the control of the end mirror of the filter cavity, following what was already done for the input mirror.

The transfer functions of the mirror motion, measured injecting white noise (with amplitude 3 V) in each degree of freedom, are plotted in the first figures of the attached document. In figure 4,open loop transfer functions are shown. In the last figures the comparison between the spectra with closed and open loops has been plotted.