As pointed out by Matteo B., the spectrum in the entry693 was not correct. After some investigation, we found the problem comes from the conversion of .DAT file.

After solving this problem, we compared the spectrum of green and infrared error signal, taken with different value of loop's UGF(10kHz and 18kHz). Now we are using UGF as 18kHz.

In the attached plot there are calibrated spectrum. The calibration factor we are using for green is 385Hz/V, for infrared is 180Hz/V.

We also multiplied a factor to make green and infrared superpose. We can see from the attached plot that green and infrared have the same trend at high frequency. This is in agreement with the fact that after 1.4kHz we should also see the effect of the green cavity pole.

The .txt files attached are not calibrated.