Participiant: Matteo.B, Yuefan and Yuhang.

Yesterday, we installed a photo dector(PD) to monitor the reflection of green mode cleaner. This PD was put in the path which is the pick off of green reflection. And the monitor point has almost all the reflected power.

Then we scan the mode cleaner by sending a ramp signal to the mode cleaner. Actually here I made a mistake which was mentioned by Matteo.L before, but I didn't pay attention. It is I use a very large ramp amplitude, which is 700mV p-p. In that case, the scan is very fast. So I cannot see the reflection peak. See attached Figure one.

Then we decrease the ramp amplitude to 100mV. And we can see the reflection peak.

We can see from the figure 2, when we are in the resonance, the reflection is around 55%.