First I removed a faraday on the bench in the reflection path and put a flipping mirror for CCFC locking. 

 

I measured 14MHz CCFC signal reflected from filter cavity. Pic.1,2 show 14MHz CCFC peak with 25 mW, 56 mW pump green. Measured CCSB power difference is 9.4dB.

 

MZ offset	pump power (mW)	p pol PLL (MHz)	CCFC 14MHz peak (dBm)
4.2	25	190	-61.9
4.8	56	120	-52.5

 

From the pump power, we can calculate the theoretical CCSB power.

 

pump power (mW)	x = sqrt(P_pump/P_th)	Normalized CCSB power x/(1-x^2)^2
25	0.56	1.2
56	0.84	9.7

 

Theoretical CCSB power difference is 10*log10(9.7/1.2) = 9.1dB which is consistent with the measurement.

 

I also measured CCFC demodulated signal with 25, 56 mW green when CCSB are off resonance of FC and CC1 is scanned. I used CC1 LO for CCFC LO and used TAMA mixer for demodulation (Pic.3,4). There is an offset in CCFC signal. We'll try to put DC block in CCFC RF signal if we can remove the offset.

 

CCFC signal with 56mW green is only 4 mVpp, so we need to amplify the CCFC RF signal.