Gas Sensor Based on Octagonal Hollow Core Photonic Crystal Fiber

This paper presents a gas sensor based on octagonal geometric structured hollow core photonic crystal Fiber. We have studied the optical properties of the proposed PCF numerically by full vector finite element method (FEM) using COMSOL Multiphysics. The octagonal lattice of the hollow core PCF has been optimized to obtain better relative sensitivity and low confinement loss. We have acquired the maximum relative sensitivity of around 97% and minimum confinement loss of similar to 0.007 dB/m at 1.67 mu m wavelength which is the absorption line of methane (CH4).