I would like to do some analysis on the filter cavities but am getting hung up on the fact the 1550 PDH error amplitude is very low. I've double checked the EOM frequency, inductor tuning in the tank circuit, and phase of the PDH loop. All seem fine. I believe it's somehow related to alignment, the REFL dips on the OFC1 1550 path are the lowest out of the 3 REFL PDs I have installed so far ( OFC1 1550, OFC1 775, OFC2 775). Below are screenshots of the error amplitude. If anyone has any other ideas to improve this please let me know. It wasn't this small in the past.

OFC1 1550

OFC1 775

OFC2 775