Simultaneous temperature and strain measurements using polarization-maintaining few-mode bragg gratings

Abstract

Simultaneous measurement of temperature and strain was demonstrated using a polarization-maintaining few-mode Bragg grating (PM-FMF-FBG) based on the wavelength and phase modulation of the even LP11 mode. The wavelength shift sensitivity and the interrogated phase sensitivity of the temperature and strain were measured to be 10 pm·°C−1 and 0.73 pm·µε−1 and −3.2 × 10−2 rad·°C−1 and 4 × 10−4 rad·µε−1, respectively, with a discrimination efficiency of 98%. The polarization interference led to selective polarization excitation of the reflection spectra, and the calculated phase sensitivity agreed with the experimental results.