Elliptical-core two mode optical-fiber sensor implementation methods

Experimental methods for the practical implementation of few-mode elliptical-core sensors are described. Techniques for desensitizing the lead-in and lead-out fibers are discussed, and results of a vibration sensor embedded in a graphite-epoxy composite are presented. A scheme using a single-mode elliptical-core fiber as the lead-in fiber and an offset circular-core single-mode fiber as the lead-out fiber is successfully implemented. Detection techniques for few-mode fiber sensors are reviewed, and a novel fringe-counting method to unambiguously detect the amplitude and direction of dynamic strain is reported.<
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