Yesterday morning (Thursday June 23th at 10 am UTC), we realigned the MZ and OPA in the squeezer box with the help of Henning. 

The procedure is quite simple but the screws touched were very sensitive.

We started with the MZ realignment to optimize its contrast. On the SQZ_MachZ_PD_DC channel it used to be between 1.03V and 1.41V, now it is between 0.34V and 2.04V (9:49 UTC). To do the alignment we only touched the two red screws on photo 1. The contrast is very sensitive to these screws, we noticed that the lower screw had a bigger impact than the upper one.

Then the green beam impinging on the OPA was realigned, using again only the last steering mirror before the OPA (see photo 2). This time, the upper screw has a bigger influence. We achieved about 2V in OPA transmission. Today it is at more than 2.1V. See figure 3 for the scan. Compared to what we had before, there are clearly less HOM. 

With this realignment, we can say that the OPA has been fully recovered.