Analyzing the sensitivity of a novel gas sensor based on photonic crystal fiber using finite-difference method

A new structure photonic crystal fiber (PCF) aiming for high sensitivity gas detection is proposed. A full-vectorial finite-difference method is used to analyze the relative sensitivity in different structure PCF. A standard eigen-value problem from Maxwell's equation can be solved by the method directly, and the propagation constants, electric fields and magnetic fields of the modes can also be obtained through the method. The relative sensitivity of three structures as a function of the fiber parameters was calculated at the wavelength of 1.3312 μm. And the relative sensitivity of the PCF at different wavelengths was given. The new structure PCF was proved to have higher relative sensitivity than the typical index-guide PCF, and is very suitable for gas sensor.