Participant: Marco and Yuhang

Since we suspected the OPO reflection signal may be too much and saturate PD. We decided to use TAMA PD. Because:

1. It separates DC and AC. So there is less probability of saturation.

2. TAMA PD amplifies signal around 15MHz. We can see that it also amplifies 14MHz quite a lot from the attached figure.

However, even after replacement, we cannot see useful information from OPO reflection. And even after reflection demodulation, we cannot see.

Anyway, we can check more things to confirm.