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Message ID: 403     Entry time: Fri Nov 19 01:24:03 2010
Author: tara 
Type: DailyProgress 
Category: optic 
Subject: changing Faraday Isolator's mount/ TF from ACAV path 

I switched the post to V-block for Faraday Isolator mount, for better stability, and adjusted the Faraday isolator to minimize back reflection to the laser.

I also measure the TF from ACAV path,  The UGF is ~65 kHz.


  The faraday isolator was installed on a standard pillar post, so I use a V block to mount it instead.

After adjusting the FI, I remeasured the beat note frequency, and the signal did not change from yesterday measurement.

(no differences between red and green plots)

blue: beat signal before fixing the ACAV opening

red: beat signal after fixing the ACAV opening

green : beat signal after re installing the FI



ACAV TF: I connect the signal output after the PDH servo box to SR560 A and SR785 B (resp)

                 Then source out from SR785 is connected to SR560 B

                 The output of SR560 is connected to SR785 B (ref) and to the VCO


The setup for SR560 is DC coupling for A and B, select A - B, gain 1, no filter.


Attachment 1: beat.png  18 kB  | Hide | Hide all
Attachment 2: ACAV_TF.png  17 kB  | Hide | Hide all
Attachment 3: data.zip  134 kB
Attachment 4: code_2010_11_18.zip  962 Bytes
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