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Entry  Mon Feb 11 19:53:59 2019, gautam, Summary, Loss Measurement, Loss measurement setup DQcheck.pdfinitialData.pdf
    Reply  Tue Feb 12 18:00:32 2019, gautam, Summary, Loss Measurement, Loss measurement setup 
       Reply  Tue Feb 12 22:59:17 2019, gautam, Summary, Loss Measurement, Y arm loss segmented.pdfconsolidated.pdf
          Reply  Wed Feb 13 02:28:58 2019, gautam, Summary, Loss Measurement, Y arm loss systUnc.pdf
             Reply  Thu Feb 14 21:29:24 2019, gautam, Summary, Loss Measurement, Inferred Y arm loss  modelPerturb.pdfposterior_modelParams.pdfposterior_Loss.pdf
                Reply  Sun Feb 17 17:35:04 2019, gautam, Summary, Loss Measurement, Inferred X arm loss  DQcheck_XARM.pdfconsolidated.pdfposterior_modelParams_XARM.pdfposterior_Loss_XARM.pdf
Message ID: 14451     Entry time: Wed Feb 13 02:28:58 2019     In reply to: 14450     Reply to this: 14454
Author: gautam 
Type: Summary 
Category: Loss Measurement 
Subject: Y arm loss 

Attachment #1 shows estimated systematic uncertainty contributions due to 

  1. ITM transmission by +/- 0.01 % about the nominal value of 1.384 %
  2. ETM transmission of +/- 3 ppm about the nominal value of 13.7 ppm
  3. Mode matching efficiency into the cavity by +/- 5% about the nominal value of 92%.

In all the measurements so far, the ratio seems to be < 1, so this would seem to set a lower bound on the loss of ~35 ppm. The dominant source of systematic uncertainty is the 5% assumed fudge in the mode-matching

To do: 

  1. Account for uncertainties on modulation depths
  2. To estimate if the amount of fluctuation we are seeing in the reflected signal even after normalizing by the MC transmission, get an estimate of statistical uncertainty in the reflected power due to 
    • Pointing jitter - is there some spec for the damped angular displacement of the TT1/TT2?
    • Cavity length in-loop residual

Bottom line: I think we need to have other measurements and simultaenously analyse the data to get a more precise estimate of the loss.

Attachment 1: systUnc.pdf  22 kB  Uploaded Thu Feb 14 01:35:23 2019  | Hide | Hide all
systUnc.pdf
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