Tapered photonic crystal fiber based Mach-Zehnder interferometer for enhanced refractive index sensing

Mach-Zehnder interferometer (MZI) based fiber-optic refractive index (RI) sensor is constructed by fusion splicing a photonic crystal fiber (PCF) between two regular single mode fibers (SMF). Using a custom made tapering equipment; the PCF is then tapered down to 60 μm that significantly enhances its ambient index sensitivity. The sensor shows RI sensitivity of 252.50 nm/RIU for RI range of 1.332 to 1.363, 475.50 nm/RIU for RI range of 1.364 to 1.392 and 1141.10 nm/RIU for RI range of 1.393 to 1.406, respectively.