Participants: Chien-Ming, Shu-Rong, and Yuhang
Today we succeed in locking the green mode cleaner (GRMC) by using the SR560 with setting the low pass at 3Hz. The S/N of PDH error signal is 300mV/3mV= 100. 

We replaced the end curved mirror of GRMC  to a higher reflectivity one 0.9996 ( the previous one is 0.9993), but the transmission efficiency is still around  52~54% not improved. Fig. 1  and Fig. 2 are the transmission spectrums of the GRMC with previous and current end curved mirror. The reason why we can't have higher transmission efficiency may be because of the impedance mismatching of the GRMC.

We also successfully locked the Mach-Zender, but have not optimized the locking parameters and measured the output power fluctuation of both MC and GRMC. Without locking the Mach-Zender, the ratio of the maximum laser power after Mach-Zender and before green EOM is 15.5mW/23.3mW = 66%.

The last thing is to successfully lock the OPO by using the same SR560 with setting the low-pass at 100Hz and the gain is 100.