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==Daily Log==
'''11/3/14'''
The 1555 lock works pretty well under vacuum when it works. Getting it to work is a problem. It seems to need different settings everyday, so apparently is very sensitive to small fluctuations. When it is working well, I've gotten between 800-1000 mW that is pretty stable in power (often less than 20 mW fluctuations), that can last for over a minute. Again the necessary settings seem to differ everyday, but usually a good lock can be achieved just by adjusting the optical feedback, proportional gain, and auxiliary servo gain. The first integrator is set at 5 kHz, the differentiator is set at at 500 kHz (gain set somewhere in the middle), and the second integrator is off.
Try optical feedback somewhere in the 100-600 mV range, and the proportional course gain at 4 clicks (the necessary settings for these two seems to be loosely inversely proportional. Sometimes the piezo voltage will max out (158.6 V), which usually means the gain is too high. Sometimes lowering the proportional gain helps, but this can also cause the laser current feedback gain to be too low, so try adjusting the auxiliary servo gain independently. Sometimes it will still lock fine at very high power with the piezo maxed out, which is confusing. Maybe it is still actually making small adjustments, which just aren't visible, or is the piezo actually doing very little?
'''10/29/14'''
I don't think the cavity leak is a problem for now--don't usually run it at less than 0.1 atm, or 760 mV, so the leak is a pretty small fraction of that. I got both locks working individually, but when trying to lock together the 1064 beam seemed to interfere with the 1555 lock. I think it's the generated 807, since there would only be interference in cavity modes where 633 was being generated (and so 807 was also). This is probably fixable with just a notch or bandpass filter. I also noticed that the error signal on the 1555 was very noisy again, at least compared to the 1064. Not the 1 kHz noise I was getting for a while, but just generally very staticy. I'm not sure if this is new or I just didn't notice it before. I eventually tracked it down to the low-pass filter, which doesn't seem to be doing anything. Switching it with the 1064 one fixed it. It's not locking well now, but presumably I'll have to retune some parameters now that there is a working low-pass filter and that there is gas in the cavity.
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