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Entry  Thu Jun 20 17:23:40 2013, Chloe, DailyProgress, ECDL, Noise Calculations saito.pdfpsd_noise.png
    Reply  Fri Jun 21 16:47:30 2013, Chloe, DailyProgress, ECDL, Noise Calculations Noise.pdf
       Reply  Mon Jun 24 11:14:04 2013, Chloe, DailyProgress, ECDL, Noise Calculations Noise.pdf
          Reply  Mon Jun 24 17:48:30 2013, Chloe, DailyProgress, ECDL, Noise Calculations Noise.pdf
             Reply  Tue Jun 25 14:14:17 2013, rana, DailyProgress, ECDL, Noise Calculations 
                Reply  Tue Jun 25 17:51:34 2013, Chloe, DailyProgress, ECDL, Noise Calculations Noise2.pdf
                   Reply  Wed Jun 26 17:13:21 2013, Chloe, DailyProgress, ECDL, Noise Calculations Noise2.pdf
                      Reply  Fri Jun 28 14:52:11 2013, tara, Notes, ECDL, laser noise requirement for locking to a refcav 
                      Reply  Sun Jun 30 22:58:45 2013, Chloe, DailyProgress, ECDL, Noise Calculations compare_experiments.pngcompare_diodes.pngcompare_gratings.pngcompare_length.png100_0068.JPG
Message ID: 1207     Entry time: Mon Jun 24 17:48:30 2013     In reply to: 1206     Reply to this: 1210
Author: Chloe 
Type: DailyProgress 
Category: ECDL 
Subject: Noise Calculations 

Quote:

Quote:

Today, I wrote up my noise calculations in a nicer way so that I have it on hand in the future. They are attached here. I found a mistake from the last elog entry, so it turns out that we are looking at a linewidth of about 440 kHz (or a PSD noise of 191 Hz/rtHz). This still meets the requirements of the experiment, and can be adjusted as necessary, since I can still increase the length of the cavity to decrease the noise. 

 There was another mistake in my calculations (sorry!) so we are actually looking at a possible linewidth of about 5.3 kHz (or noise level of 0.03 Hz/rtHz). This is very low, so we are looking at using a current driver from Thorlabs since we have room in our noise budget, and this would make the assembly much easier since the parts fit together. Waiting for a response from Thorlabs about their noise levels for current drivers.

Attached are the corrected calculations. 

I added some additional explanation for the fact that the noise reduction was not dependent on frequency (see attached). I also added references for the data that I used. 

I spent awhile dealing with Thorlabs customer service trying to figure out about their lowest noise current driver (250 mA), which is the LDC205C. They are still working on getting an answer as to the noise level of this current driver. 

The next step is to start considering the mechanical setup of the ECDL and see if we need to order any special mounts for this. Tomorrow I will draw up more of a sketch for the mechanical apparatus, since Tara had talked about possibly getting some parts machined. 

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