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Message ID: 2633     Entry time: Tue Feb 9 13:29:15 2021
Author: rana 
Type: Noise Hunting 
Category: Laser 
Subject: how to reduce noise in fibers due to wind and temperature 

In principle, the noise in optical fibers should be well predicted by the Wanser formula for thermo-refractive noise. Somewhere out there in the world, people are working on making a fiber that has opposite signs for the dn/dT and the d(dL/L)/dT, but until then TR is the limit.

However, non-fundamental temperature fluctuations are typically bigger than thermodynamic temperature fluctuations in the 0-1 Hz band. Above ~50 Hz, acoustic noise also becomes important.

Here are a collection of links with sort of simple ways to reduce these effects:

  1. IOFFE: putting the fiber in a box; related paper here.
  2. https://www.ppc-online.com/fiber-protection-tubes
  3. asdf

 

Wondering if we can do something easy for the relative laser noise measurements. Like putting the fiber in a metal tube with foam inside.

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