Strain and temperature discrimination using two sections of PMF in Sagnac interferometer

Abstract

A fiber sensor is proposed and demonstrated for strain and temperature discrimination by inserting two sections of a commercialized panda-type polarization maintaining fiber in a Sagnac loop. The proposed sensor employs only one type of commercialized high birefringent fiber and includes no complicated fabrication process. It tends to be a simple and cost-effective alternative to other Sagnac interferometers used for simultaneous measurement of strain and temperature. The strain and temperature sensitivities of the sensor are both theoretically discussed and experimentally measured. Experimental results show that the sensor is capable of obtaining both high sensitivities up to −1.495 nm/°C and 20.67 pm/με and low discrimination errors of ±0.13 °C and ±14.06 με respectively for temperature and strain. The sensor has much potential in applications which require low cost, easy fabrication as well as high temperature- and strain- sensitivities and good discrimination accuracies.