J. Oberling, S. Doravari

Pursuant to LHO WP 7542, we temporarily swapped the laser for the ETMy optical lever with a frequency stabilized HeNe laser.  This new setup is sitting underneath the cooler for the existing optical lever laser, with the power supply sitting on top of the cooler (see attached pictures).  If working around this area, please be aware of this new setup.  Edited to add: We have the fiber coming out of the top of the cooler, and the lid propped open (as seen in the pictures), so please take care when working around the setup.

This laser runs at ~0.6mW, so to get a usable signal we had to increase the whitening gains at the OpLev whitening chassis; the whitening gain for each QPD segment was increased from 0 dB to 39 dB.  This gain change will need to be reverted when this temporary laser setup is removed.  Before and after pictures of the output configuration switches of the OpLev whitening chassis are attached for future reference.