I replaced the AOM driver by the miyoki-san's one. The "mori-coart" was put between the AOM driver and the heat sink. And also I simplified the cable configuration around the AM input of the AOM driver. The cable configuration before and after the simplification are as follows:
(old) DC power supply (banana cable) ------------ (BNC) I connector (BNC) ------------- (SMA) sma2smb conector (SMB) AOM driver AM input
(new) DAC ------- Dsub-BNC converter (BNC) ---------- (SMB) AOM driver
The channel name connecting to the AOM driver AM input is K1:PSL-AOM_AM_IN. The input voltage is set to 1.5 V.

After replacement, I found the banana cable is broken. The problem came from not the AOM driver but that cable

Anyway, the FSS loop is healthy now.