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Entry  Tue Aug 18 15:52:27 2009, Jenne, Update, PSL, MZ 
    Reply  Tue Aug 18 19:57:47 2009, rana, Jenne, Update, PSL, MZ MZ_RFAMmon_setup_small.jpgMZ_RFAMmon_SpecAnalyzer_small.jpgMZ_EOM_IRrefl2_small.jpg
       Reply  Wed Aug 19 17:11:33 2009, Jenne, Update, IOO, QPDs aligned 
Message ID: 1926     Entry time: Tue Aug 18 19:57:47 2009     In reply to: 1925     Reply to this: 1928
Author: rana, Jenne 
Type: Update 
Category: PSL 
Subject: MZ 

- we finished the MZ alignment; the contrast is good.

- we did the RFAM tuning using a new technique: a bubble balanced analyzer cube and the StochMon RFPD. This techniques worked well and there's basically no 33 or 166 RFAM. The 133 and 199 are as expected.

- the MC locked right up and then we used the periscope to align to it; the transmission was ~75% of max before periscope tuning. So the beam pointing after the MC should be fine now.

- the Xarm locked up with TRX = 0.97 (no xarm alignment).


If Rob/Yoichi say the alignment is now good, the we absolutely must center the IOO QPDs and IP POS and IP ANG and MC TRANS  today so that we have good references.



The first photo is of our nifty new setup to get the beam to the StochMon PD.  The MZ transmitted beam enters the photo from the bottom right corner, and hits the PBS (which we leveled using a bubble level).  The P-polarization light is transmitted through the cube, and the S-polarization is reflected to the left.  The pure S-polarized light hits a Beam Splitter, which we are using as a pickoff to reduce the amount of light which gets to the PD.  Most of the light is dumped on an aluminum dump.  The remaining light hits a steering mirror (Y1 45-S), goes through a lens, and then hits the StochMon PD.  While aligning the MZ to maximize visibility, we look at the small amount of P-polarized light which passes through the PBS on an IR card, and minimize it (since we want to be sending purely S-polarized light through the EOMs and into the MC).

The second photo is of a spectrum analyzer which is directly connected to the RF out of the StochMon PD.  To minimize the 33MHz and 166MHz peaks, we adjust the waveplates before each of the EOMs, and also adjusted the tilt of the EOM holders.

The final photo is of the EOMs themselves with the Olympus camera.

Once we finished all of our MZ aligning, we noticed that the beam input to the MC wasn't perfect, so Rana adjusted the lower periscope mirror to get the pointing a little better.  

The MZ refl is now at 0.300 when locked.  When Rana reduced the modulation depth, the MZ refl was about 0.050 .  Awesome!


Attachment 1: MZ_RFAMmon_setup_small.jpg  66 kB  Uploaded Wed Aug 19 10:20:02 2009  | Hide | Hide all
Attachment 2: MZ_RFAMmon_SpecAnalyzer_small.jpg  136 kB  Uploaded Wed Aug 19 10:20:12 2009  | Hide | Hide all
Attachment 3: MZ_EOM_IRrefl2_small.jpg  49 kB  Uploaded Wed Aug 19 10:21:01 2009  | Hide | Hide all
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