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Message ID: 6088     Entry time: Thu Dec 8 11:59:53 2011
Author: Zach 
Type: Update 
Category: RF System 
Subject: fringing indeed 

Here is a trend of 11 & 55 I&Q, along with the EOM temperature and PSL RMTEMP signals. You can see that there is definitely some fringe-like behavior for monotonic changes in temperature. This is consistent with what I have seen on the gyro table in the past.

Some other notes:

  • The EOM temperature (or at least the sensor temperature) seems to track RMTEMP almost exactly when there is no foam box on the EOM. I have verified that the max-min swing here is the same for both signals (~0.77 K).
  • Something crazy appears to happen at ~10:15, and all the RAM signals get much noisier. Does anyone know what happened at this time (2:15am local)?

We ought to get to the bottom of the fringing. The CTE of LiNbO3 is ~2 ppm/K, so given that the wavelength is on the order of 0.5 K, this is probably not caused by the etalon effect (2ppm/K * 0.5K * ~1cm << 1064nm).

RAM_with_temp_overnight.png

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