Torsion and Temperature Sensor based on Polished MSM Structure

A novel optic-fiber torsion and temperature sensor has been proposed and fabricated by sandwiching a segment of a triangular shaped single-mode fiber between two multimode fibers. This structure provides the sensitivity of torsion, which results from the destruction of the rotational symmetry of the optical fiber. Experimental results show that the polished multimode single-mode multimode (MSM) sensor has the ability of determining the twist direction and the amount of torsion with sensitivities of 0.196 nm/(rad $\cdot \,\,\text{m}^{-1}$ ) and −0.18 nm/(rad $\cdot \,\,\text{m}^{-1}$ ) at dip 1455 nm and dip 1505 nm, respectively. In temperature measurement, the sensitivities provided by the two dips above are 0.058 nm/° and 0.072 nm/°, respectively. The stability and the feasibility of the proposed sensor are experimentally verified.