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Entry  Tue Mar 8 06:29:06 2011, kiwamu, Update, Green Locking, Intensity noise setup 
    Reply  Wed Mar 9 04:46:13 2011, kiwamu, Update, Green Locking, more intensity noise measurement intensity_setup.pngIntensityNoise.png
       Reply  Wed Mar 9 18:17:11 2011, kiwamu, Update, Green Locking, Intensity noise coupling diff_noise.pngIN_TF.png
          Reply  Thu Mar 10 14:06:54 2011, kiwamu, Update, Green Locking, Intensity noise limits the beatnote sensitivity diff_noise_Mar8.pngIN_TF_complete.png
             Reply  Thu Mar 10 14:22:58 2011, kiwamu, Update, Green Locking, Intensity noise limits the beatnote sensitivity 
                Reply  Thu Mar 10 14:29:05 2011, Koji, Update, Green Locking, Intensity noise limits the beatnote sensitivity 
                Reply  Thu Mar 10 14:30:53 2011, rana, Update, Green Locking, Intensity noise limits the beatnote sensitivity 
                   Reply  Thu Mar 10 16:00:53 2011, Aidan, Joe, Update, Green Locking, Intensity stabilization loop using beatnote DC. P1000313.jpgP1000314.jpgP1000315.jpgGREEN_ISS_LOOP.pdfScreenshot-C1ALS_OVERVIEW.adl.png
                      Reply  Thu Mar 10 21:45:34 2011, rana, Update, Green Locking, Intensity stabilization loop using beatnote DC. 
Message ID: 4397     Entry time: Thu Mar 10 14:06:54 2011     In reply to: 4392     Reply to this: 4398
Author: kiwamu 
Type: Update 
Category: Green Locking 
Subject: Intensity noise limits the beatnote sensitivity 

We are limited by the intensity noise of the X arm transmitted green light.

Since the intensity noise from the PSL wasn't big enough to explain the differential noise (#4392), so this time I measured the noise contribution from the X arm transmitted light.
diff_noise_Mar8.png

 

(coupling measurement)

  IN_TF_complete.png

  I performed the same intensity noise coupling measurement, but this time between the DC signal of the beatnote RFPD and the beatnote signal.

 While measuring it, I excited the intensity of the PSL laser by using the same AOM like I did yesterday. This AM cause the observable intensity noise on the beatnote RFPD.

With the excited AM, we can pretend to have an excited AM on the green transmitted light from the X arm, of course assuming the intensity noise coupling from the PSL is less.

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