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Entry  Fri Jan 4 19:04:29 2019, awade, DailyProgress, RFAM, Time to look at RF AM and RIN 
    Reply  Wed Jan 9 17:25:38 2019, anchal, DailyProgress, RFAM, Time to look at RF AM and RIN RIN_DBN_Coherence_Measurement.pdf
       Reply  Wed Jan 9 19:05:56 2019, anchal, DailyProgress, RFAM, Time to look at RF AM and RIN 
          Reply  Thu Jan 10 11:38:53 2019, awade, DailyProgress, RFAM, Time to look at RF AM and RIN 
             Reply  Thu Jan 10 17:30:24 2019, anchal, DailyProgress, RFAM, Time to look at RF AM and RIN 
                Reply  Thu Jan 10 18:52:20 2019, anchal, DailyProgress, RFAM, Time to look at RF AM and RIN 
                   Reply  Sat Jan 12 13:11:02 2019, awade, DailyProgress, RFAM, Time to look at beatnote after RF AM and RIN tuneup 
                      Reply  Wed Jan 16 11:07:41 2019, anchal, DailyProgress, NoiseBudget, Beatnote after RF AM and RIN tuneup LaserPowerNoise_to_BNFreqNoise_TF.pdfIN_to_BN_TF.zipTransmission_RIN_Jan15_2019.pdfRIN_Measurement_20190115.zip20190116_130937noiseBudget.pdf
    Reply  Thu Jan 10 14:19:46 2019, anchal, DailyProgress, RFAM, Time to look at RF AM and RIN 
Message ID: 2275     Entry time: Wed Jan 9 17:25:38 2019     In reply to: 2273     Reply to this: 2276
Author: anchal 
Type: DailyProgress 
Category: RFAM 
Subject: Time to look at RF AM and RIN 

I measured RIN of the two paths yesterday through taking spectrum of transmission PDs and measured cross-correlation with the Beatnote.


Measurement conditions:

  • Beatnote frequency was not temperature controlled and was arounf 127 MHz slowly increasing.
  • Note, this is near the edge of the DC-125 MHz wideband RF detector used for BN measurement.\
  • PLL Actuation slope was 5 kHz/V
  • Cross-correlation was measured as a FFT group measurement by SR785 using Cross Spec measurement.
  • Averaging was on and set to 50 with Linear averaging.

Conclusions:

From the plots attached, it is clear that RIN of both paths have a peak near 3 kHz but the south path has excessive RIN in comparision to North parth and has much more coherence with BN. I'm looking into possible RF AM in south path.


Edit Wed Jan 16 14:08:03 2019 :

I forgot to convert the noise spectrum measured to laser power spectrum earlier. I am also realizing now that I should have measured the transmitted power to get the RIN. So this measurement only provides Intenisty (or Power) noise of transmitted lasers. I'm attaching the fixed plot now.

Attachment 1: RIN_DBN_Coherence_Measurement.pdf  53 kB  Uploaded Wed Jan 16 14:10:55 2019  | Hide | Hide all
RIN_DBN_Coherence_Measurement.pdf RIN_DBN_Coherence_Measurement.pdf
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