Side polished fiber Bragg grating sensor for simultaneous measurement of refractive index and temperature

Abstract

A fiber sensor to achieve simultaneous measurement of refractive index and temperature is proposed by using a side polished fiber Bragg grating. The reflective wavelength of side polished fiber Bragg grating shifts with the ambient refractive index and local temperature. By overlaying half of the polished surface of fiber Bragg grating with liquid material, simultaneous discrimination of liquid refractive index and local temperature with dual reflective Bragg wavelengths is demonstrated. The refractive index sensitivity is from 4.99nm/riu to 252.78nm/riu when refractive index changes from 1.4098 to 1.4479, and the temperature sensitivity is 0.012nm/°C.