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Entry  Mon Mar 25 22:56:42 2013, Evan, DailyProgress, Electronics Equipment, Frequency readout noise of PDH loop res_and_pdh.pdferrsig_smooth_derivative.pdferrsig_voltage_noise.pdferrsig_freq_noise.pdf
    Reply  Tue Mar 26 10:00:19 2013, Evan, DailyProgress, Electronics Equipment, Frequency readout noise of PDH loop 
    Reply  Thu Mar 28 12:36:27 2013, Zach, DailyProgress, Electronics Equipment, Frequency readout noise of PDH loop 
       Reply  Sat Mar 30 01:42:16 2013, tara, DailyProgress, Electronics Equipment, Frequency readout noise of PDH loop 
Message ID: 1132     Entry time: Thu Mar 28 12:36:27 2013     In reply to: 1128     Reply to this: 1133
Author: Zach 
Type: DailyProgress 
Category: Electronics Equipment 
Subject: Frequency readout noise of PDH loop 

Is this really the input noise of the PDH servo (i.e., output noise / servo TF)? If so, it seems pretty high. With the right components, you should to be able to do ~100x better.

Quote:

Tara was able to tame the cavity servo loop. The third attachment is the result of several SR785 measurements of the error signal power spectrum. I converted this to a frequency noise power spectrum (fourth attachment) by extracting the voltage/frequency calibration factor from the error signal as follows.

 

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