Refractive index measurement using a photonic crystal fiber

An optical waveguide for measuring the change of refractive index (RI) by using a photonic crystal fiber is designed. The simulation results show that a variation of 3.5% refractive index unit (RIU) could shift the resonant wavelengths of 450 and 110 nm when the RIs of liquid are 1.5 and 1.7, respectively. The sensitivities of 8×10?7 and 3.2×10?6 RIU are thus able to be achieved for the RIs of liquid of 1.5 and 1.7, respectively.