The impact of polarization‐maintaining and multimode fibre lengths on strain and temperature sensitivities of single‐mode–multimode–polarization‐maintaining–multimode–single‐mode‐based fibre optic sensors

Abstract

A fibre loop mirror sensor is proposed and demonstrated for strain and temperature measurements in experiment. In these schemes, fibre loop mirrors are constructed with single-mode-multimode-polarization-maintaining-multimode-single-mode optical fibre (SMPMS) structures. The strain and temperature characteristics of the sensor, depending on the lengths of multimode fibre (MMF) and polarization-maintaining fibre (PMF), are studied in the experiment. The results indicate that PMF and MMF lengths have less impact on strain sensitivity but a remarkable impact on temperature sensitivity, which is consistent with the theoretical analysis. The best strain and temperature sensitivities of an SMPMS structure sensor can reach up to 39.0 pm/με and 2.366 nm/°C, respectively. The sensors have the merits of easy fabrication, cost-efficiency and high temperature sensitivity and are quite suitable for fields requiring high-precision measurement. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.