David Notebook: Difference between revisions

 

==Daily Log==

I tried to track down where the noise was coming from. The DC error output on the vescent box only is noisy when it's connected to the error signal and the RF is on (doesn't matter whether the laser is on and there is actually an error signal). The full height is about 15 mV of noise. I checked the laser diode output using a photodiode and the noise doesn't seem to be coming from there. Most likely seems the RF amplifier in the circuit, although the low pass filter isn't cutting this as much as I'd think either. I tested the amplifier by itself though and it didn't show any sidebands, which would have been the obvious cause. It does have signals at integer multiples of the input RF signal, but those are all around 10 db lower. I checked the same amplifier on the 1064 setup and it showed similar behavior. The vescent box on the 1064 also shows similar noise with, although slightly less, so maybe nothing is broken and this has always been there.