Multi-Wavelength Twin-Core Fiber Optic Sensors

Abstract

Fiber optic sensors have unique advantages and capabilities when applied to experimental stress analysis, particularly at high temperatures1, and to the nondestructive evaluation of composite materials and structures2 . For many applications, practical considerations dictate the need for simultaneous temperature and strain observations or the resolution of serially distributed flexural strain along the lightguide sensor. In a dual mode fiber, wherein a perturbation is sensed by measuring the change in differential phase between modes, multiple wavelength operation can be used to separate thermal and stress effects or to resolve the distribution of flexural strain along a bent fiber.