<title>Erbium-doped fiber ring laser strain sensor</title>

Abstract

We describe a fiber ring strain sensor configuration which incorporates an active fiber gain section to allow lasing within the ring. Analysis of the beating between modes of this ring laser provides a measure of the optical path length in the ring, and thus strain applied to the fiber. The sensor provides an output frequency which can be tracked to determine the integrated strain over the length of the fiber ring. Results are presented showing the sensor response up to a fiber strain of approximately 4000 micro-strain.