First I aligned BAB to FC. The optimal p pol PLL frequency without green was 300MHz and BAB power before FC was 435uW. The maximum IR transmission of FC was 470.

Then I checked the CCFC error signal. I optimized the p pol PLL frequency to maximize the CCFC error signal. The optimal p pol PLL frequency with 20mW green was 240MHz and the CCFC error signal was 118mVpp. The setting of CC detuning is reported in elog2521. The setting of LEMO cables for demodulation is as follows.

The attached figure shows CCFC error signal. The mode matching is fixed to 0.9. We need to adjust the demodulation phase and CC detuning.