I installed the another double-pass AOM — to be precise, I installed a lens, QWP, and mirror for composing double-pass AOM system.
The attached picture shows the installed optics.
The following is the procedure.

1. Adjusted the alignment to maximize the -1st order diffracted beam power.
   The diffraction efficiency was about 85%.
2. Then put a lens (f=75mm) and QWP to collimate the beam.
3. Put a mirror and adjusted the alignment to let the diffracted beam enter the AOM.
4. Adjusted the alignment with two STMs and one end mirror by monitoring double-passed beam power.
5. I got about 72% double-pass diffraction efficiency at the end.

I have not investigated the beam jitter of this system.
So I gonna measure the beam jitter with frequency scan and then install optics for ISS.