Birefringence manipulation in tapered polarization-maintaining photonic crystal fiber Mach-Zehnder interferometer for refractive index sensing

A temperature insensitive, compact and high resolution refractive index measurement system using tapered polarization maintaining photonic crystal fiber (PM-PCF) Mach-Zehnder interferometer (MZI) is proposed. The sensor exhibits sensitivity of 20.53 nm/RIU with very high refractive index resolution of 1.2175 x 10(-5) RIU and 252.6906 dBm/RIU within the refractive index range from 1.33 to 1.37. The bire-fringence value varied from 1.90619 x 10(-5) to 1.86978 x 10(-5) with the corresponding change in refractive index. The core and clad having different propagation constant and the changes in the optical path length and hence a change in interference pattern is correlated with the minute changes in refractive index of the subjected sample. (C) 2016 Elsevier B.V. All rights reserved.