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Entry  Tue Apr 10 00:50:56 2012, frank, tara, DailyProgress, optic, bad PBS 
    Reply  Wed Apr 11 02:44:29 2012, frank, tara, DailyProgress, optic, bad PBS beat_2012_04_10.png
       Reply  Wed Apr 11 20:30:50 2012, frank, tara, DailyProgress, NoiseBudget, Electronic noise verification beat_2012_04_11.png
          Reply  Thu Apr 12 22:22:12 2012, frank, tara, DailyProgress, NoiseBudget, Electronic noise + shot noise verification 
Message ID: 909     Entry time: Wed Apr 11 20:30:50 2012     In reply to: 906     Reply to this: 911
Author: frank, tara 
Type: DailyProgress 
Category: NoiseBudget 
Subject: Electronic noise verification 

  We are checking the noise contribution from electronics readout of our system to get better noise budget estimation. We added detection noise from RCAV and ACAV systems in the noise budget. They are comparable to the estimated shot noise level.

    We measured the noise level of the PDH detection for RCAV and ACAV system, the corresponding error signal slope.The results are summarized in the table below.

Setup: 1mW input to each cavity, TTFSS: Common/Fast = 900/800,

  RCAV ACAV
Pwr input [mW] 1 1
V_DC (RFL RFPD) [V] 1.7 1.47
Err signal Slope [kHz/V] 40.3 81.7
Detection Noise [nV/rtHz] 35 23

 

Detection Noise x Err signal slope gives us the electronic noise contribution in absolute frequency unit. From the above table, we obtain

1 mHz/rtHz and 1.8 mHz/rtHz from RCAV and ACAV systems, respectively.

 The electronic noise from RCAV and ACAV systems are added to the noise budget. In the plot below, I removed the traces for Spacer noise and thermo optic noise to make the plot less crowded, but their contribution are included in the total noise.

beat_2012_04_11.png

 

More to come:

  • Shot noise measurement for ACAV/RCAV/beat
  • TTFSS OLG TF, suppressed laser frequency noise

 

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