When I try to lock the cavity, it's not very stable yet. The transmitted power fluctuates alot.

I try changing the gains, but still could not stabilize the lock . The transmitted beam power is about 60% during the stable lock (I got it nicely locked for 5- 10 mins.)

After RefCav is locked, I'll try to optimize the transmitted power, by adjusting the lenses' positions before moving on to work on ACav