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Entry  Mon Dec 13 21:03:30 2010, Kevin, Update, Electronics, RF Photodiode Characterizations 
    Reply  Tue Dec 14 04:14:53 2010, rana, Update, Electronics, RF Photodiode Characterizations 
Message ID: 4048     Entry time: Mon Dec 13 21:03:30 2010     Reply to this: 4051
Author: Kevin 
Type: Update 
Category: Electronics 
Subject: RF Photodiode Characterizations 

[Koji, Jenne, Kevin]

Jenne worked on fixing REFL11 last week (see elog 4034) and was able to measure an electrical transfer function. Today, I tried to measure an optical transfer function but REFL11 is still not responding to any optical input. I tried shining both the laser and a flashlight on the PD but could not get any DC voltage.

I also completed the characterizations of POX. I redid the optical transfer function and shot noise measurements. I also took a time series of the RF output from the PD when it was powered on with no light. This measurement shows oscillations at about 225 MHz. I also measured the spectrum with no light which also shows the oscillations at 225 MHz and smaller oscillations at ~455 MHz.

The plots can be found at http://lhocds.ligo-wa.caltech.edu:8000/40m/Electronics/POX?action=show.

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