After putting in the new EOM driver at 37 MHz, we have been unable to mode match into the south cavity. After beam profiling the path, we found that since we changed the EOM and changed the path, the cylindrical lens is no longer cleaning the incoming mode properly. We found ellipticity of 0.88 and 1.16 before and after the EOM. As we anyways had plans for putting in the mode cleaner on the south path as well, we have decided to do it now when the incoming path to cavity is anyways badly misaligned and mismatched.
Steps for putting in mode cleaner:
0) Profile the beam of existing marks to be able to revert back if required.
1) Remove the cylindrical lens and associated optics and profile the beam after the ISS amplitude modulation.
2) Install 14.75 MHz resonant EOM with waveplates and the mode cleaner and mode match into it.
3) Install the PMC reflection 14.75 MHz RFPD
4) Estimate and/or profile the beam from the mode cleaner and adjust the lens for a clean mode matching with the South Cavity.