Nishino,

By scaaning frequency, I measured the mode-mtching ratio of the current setup.There were 4 HOMs (both HG and LG). The mode-matching ratio is:

4.90 / (4.90 + 0.337 + 0.097 + 0.097 + 0.097)*100 = 88.7 %

The injection current was 1.1 A.

Also I locked the cavity by Moku:lab. Environmental sound seems to be too big and the locking was not stable only with a feedback onto PZT. It would need something like a shield for a stable locking.