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Entry  Thu Aug 22 00:29:32 2013, tara, DailyProgress, NoiseBudget, installed EOAM EOAM.jpgnb_short_cav.png
    Reply  Thu Aug 22 20:31:28 2013, tara, DailyProgress, NoiseBudget, installed EOAM nb_short_cav.pngnb_short_cav.figRFAM.jpg
Message ID: 1309     Entry time: Thu Aug 22 00:29:32 2013     Reply to this: 1311
Author: tara 
Type: DailyProgress 
Category: NoiseBudget 
Subject: installed EOAM 

I installed an electro-optic amplitude modulator (EOAM) in RCAV path. Better optimization will be needed to reduce extra noise.

 EOAM.jpg

above, the setup for ISS actuator, the first 1/2 wave plate rotates p-beam to s-beam, EOAM, 1/4 Wave plate that tuned so that the output beam is 45 degree so the power transmitted through the final PBS is reduced in half.

 

After the EOAM was added, I checked the beat noise and saw a bump at ~ 2 kHz, see the figure below(blue plot). This was from the EOAM even though there was no input drive. It disappeared after I changed the EOAM position by rotating it a bit( yellow plot). I have not finished with optimizing it yet. I'm thinking about what kind of mechanism that causes the noise here.

 

nb_short_cav.png

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