[Pierre, Yuhang, Eleonora P.]

After the simulation of OLTF and the check of the SHG transmission signal level, Pierre realized the corresponding circuit. It includes the modify of 20 components(resistors and capacitors). These changes will be uploaded to our wiki.

Then we installed it on the NIM rack, we tested both manual and auto lock of it. It works very well and can lock SHG also pretty well. Then we measured the OLTF. The measured result is plotted and shown in the attached figure.

We can see from it that the phase margin is enough. However, the gain margin is not enough. Besides, there are several peaks around 20kHz have phase around -180. This may also bring some instabilities. So we decide to reduce the gain to reduce unity gain frequency from 3.55kHz to around 2kHz. So that we can have a better gain margin and also avoid the phase of peaks crossing -180deg.