Methane and hydrogen sensor based on photonic crystal waveguide

A gas sensor is designed based on a triangular lattice air-hole photonic crystal waveguide (PCW), and the concentration of the mixed gas is measured by selectively coating a sensitive film whose refractive index changes with the gas concentration in the PCW. The transmission characteristics of light in the waveguide are studied by time domain finite element method (FDTD). The results show that the appropriate structural parameters can be selected, and the mixed gas of methane and hydrogen can be accurately measured by using two channels without interference. The sensor has compact structure and good optical properties, which provides a new idea for the detection of various gases.