Following work in 2958, I had to tune the position of the input oplev tilt PSD to have enough space to move the shift PSD on its rail.

To perform decoupling between shift and tilt, I injected a line at 0.94 Hz (length mechanical resonance frequency) with 200 counts amplitude on input mirror length.

I moved the lens on the rail, for each position recenter the beam on the tilt PSD and measured the peak amplitude at 0.94 Hz.

Result is reported in fig 1.

It seems that for pitch, the ideal lens position should be about 12.2 cm while it should be about 11 cm for yaw.

For yaw, the peak was always present and as suggested by Matteo could be caused by the easy excitation of yaw when exciting length.

EDIT : corrected z units from mm to cm.