Multiplexed, High- And Low-Sensitivity Fiber-Optic Strain/Temperature Sensor

Abstract

An intrinsic, wavelength-division-multiplexed, high- and low-sensitivity fiber-optic sensor is proposed and analyzed as a possible alternative to the existing optical fiber-sensing methods used in real-time temperature and strain evaluations. The sensor unites two existing technologies: (1) the dual core, single-mode, cross-talk phenomena exhibiting relatively low sensitivity and (2) the Fabry-Perot interferometric sensing phenomena that is known for its high sensitivity. The sensor uses the wavelength sensitivity of fused, tapered, single-mode couplers as a method of multiplexing the two widely exploited sensors outlined above. The sensor configuration consists of two independent coherent sources of differing wavelengths, a wavelength division multiplexer/demultiplexer, a center-cleaved, fused, biconnically tapered, single-mode coupler/splitter, and partially reflective, mirrored surfaces at designated locations along the fiber. Thus, a unique sensing arrangement having two independent (high- and low-sensitivity) sensors functioning simultaneously is realized.