Sheila, Daniel

Today we increased the power from the laser onto the fiber locking BBPD, from 1mW to 9mW.  We first tried 25mW, but we might have been overdriving the phase frequency discriminator with that much power, the pll was able to lock but with a lot of excess noise.  With 9mW we get a large enough beat note that the frequency comparator is working well, but we do not see excess noise on the beatnote on the RF analyzer.  (will double check RF level in the morning)  This means that the autolocker is now working for the PLL.  Daniel also changed the attenuators for the VCO input to the frequency comparator, I think to 20dB ( I also need to double check this in the morning). 

We also looked into why the photodiode gains were not changing.  The power supply in the beckhoff unit for that chassis was not connected to the modules, so none of the binary outputs were working.  After we connected them we adjusted the calibration of the fiber trans, IR laser monitor, and fiber polarization monitor PDs, which we originally did taking into account the non working gain settings.  

We also found a on Track QPD to monitor the beam position on the green refl diode.  I replaced the HR steering mirror in the path the the PD with a 80% reflector, to make a pick of for the QPD.  We had completely lost the return beam, presumably because of seismic commissioning, so we didn't align this yet.