I took the TF of the OPO TEC Loop, with the plot attached below.

The blue curve is the original loop, with UGF @30mHz, and a phase margin of ~44deg.

I increased the gain by a factor of 1.9, making the Gain = 1.33 in the LOOP SHAPE manual in MEDM. (Other filters unchanged)

Now we have a UGF@50mHz, and a phase margin of 50deg. This should make the loop more stable and faster. (Red curve.)

For the SHG, the loop looks good enough with UGF @25mHz, and phase margin ~50deg.

Notes on how to take the loop TF:

OPO/SHG TEC servo screen --> little screen under Excitation

Set the frequency and amplitude (10E-3V worked well) --> Switch on --> Click reset

You will need to integrate for a good while until the number stops fluctuating.

If you change the frequency or amplitude, you need to hit reset.

We should make sure these excitations are off after taking the measurements.