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Entry  Thu Sep 16 15:21:21 2021, Paco, DailyProgress, 1418 nm AUX ECDL, Free space AOM 
    Reply  Wed Sep 22 16:44:34 2021, Radhika, DailyProgress, 1418 nm AUX ECDL, Free space AOM 
       Reply  Mon Oct 4 17:44:34 2021, Radhika, DailyProgress, 1418 nm AUX ECDL, Free space AOM 
          Reply  Tue Oct 19 13:52:03 2021, Radhika, DailyProgress, 1418 nm AUX ECDL, 1418nm ECDL Frequency noise ECDL_diagram.pdfECDL_FNM_13-10-2021_151524.pdf
             Reply  Tue Mar 8 09:32:56 2022, Paco, DailyProgress, 1418 nm AUX ECDL, 1418nm ECDL Frequency noise schematic.pngraw_bn_spectrum.pngphase_timeseries.pngecdl_freqnoise.png
Message ID: 1927     Entry time: Tue Oct 19 13:52:03 2021     In reply to: 1926     Reply to this: 1928
Author: Radhika 
Type: DailyProgress 
Category: 1418 nm AUX ECDL 
Subject: 1418nm ECDL Frequency noise 

Attachment 1 is a diagram of the current setup for measuring ECDL frequency noise. Since the last update, I have fed the beat note signal to a mixer, using a 35 MHz LO sourced from the Marconi. The resulting demodulated signal is passed to a low-pass filter, removing the 2f sinusoidal term (any trace of the frequency difference) and leaving behind a low-frequency term containing frequency noise information of the original beam (accumulated over the length of delay line).

I took spectra of the resulting signal using the SR785 (Attachment 2). Note that these units are still in V/rtHz, since the signal has not been calibrated to the appropriate units for frequency noise, Hz/rtHz. Finding the calibration term will involve study of delay line frequency discrimination. 

Attachment 1: ECDL_diagram.pdf  18 kB  Uploaded Tue Oct 19 14:52:23 2021  | Hide | Hide all | Show all
ECDL_diagram.pdf
Attachment 2: ECDL_FNM_13-10-2021_151524.pdf  26 kB  Uploaded Tue Oct 19 14:52:43 2021  | Show | Hide all | Show all
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