Simultaneous Measurement of Curvature and Temperature Based on a Simple Cascaded Fiber Interferometer

Abstract

An optical fiber sensor based on thin-core fiber (TCF) and no-core fiber (NCF) interference structures is presented and experimentally demonstrated to measure the curvature and temperature. The fabrication process of the sensor is simple and convenient, and the sensing part is formed by cascading a TCF and an NCF between two single-mode fibers. The dips at resonant wavelengths are generated in the optical transmission spectrum owing to mode interference. The experimental results indicate that an optical curvature sensitivity of −5.76 nm/m −1 is achieved in the linear range of 0.9895-3.2817 m −1 and that a temperature sensitivity of 0.18 nm/ • C is obtained in the temperature range of 25-55 • C. Additionally, the cross sensitivity problem is solved using the coefficient matrix measurement method, and the cross-sensitivity is as low as 0.0312 m −1 / • C. Therefore, the sensor exhibits a highly reproducible technique and low cross sensitivity, which has a wide range of application prospects in the accurate measurement of mechanical arms and structural health monitoring.