Evan, Gabriele

We plugged the LSC-EXTRA_AO_2_EXC output into the excitation 1 of the MC board. In this way we could inject a 100 Hz line (100 counts amplitude) into the laser frequency and check the coupling to the IMC transmitted power.

As described in 17129, we used a script to compute in real time the transfer function from our laser frequency excitation to the IMC transmitted RIN. The attached plot shows that we got the expected linear dependency of the TF on the IMC locking servo. Unfortunately we don't have enough range in the MC offset to go to zero. We need about -15 V to go to zero coupling.

For the moment being, we left the offset adjusted to -10 V. This reduces the coupling of frequency to intensity noise by a factor 2.6