A tunable methane gas sensor is proposed and optimized by introducing a gas-sensitive film into the cladding air holes of hollow core photonic crystal fiber (HC-PCF). The characteristics of dispersion curve and group index of band-gap photonic crystal fiber are analyzed by the Plane Wave Expansion Method (PWM) and Finite Element Method (FEM). The results show that the micro-fluid infiltration technology can effectively improve the slow light characteristics of photonic crystal fiber (PCF), and make the central wavelength of slow-light region at the target gas absorption to discriminate the gas species. The coating technique allows the spectrum of absorption enhancement factor linearly shift with the increase of methane concentration, and the sensitivity can reach up to 0.794 nm/%. The sensor is simple and reliable with good linearity, which provides a new way for mixed gas measurements.

提出并通过在空心光子晶体光纤（HC-PCF）的包层气孔中引入气体敏感膜来优化甲烷气体传感器。利用平面波扩展法（PWM）和有限元法（FEM）分析了带隙光子晶体光纤的色散曲线和基团指数。结果表明，微流体渗透技术可以有效改善光子晶体光纤（PCF）的慢光特性，并使慢光区域的中心波长位于目标气体的吸收位置，以区分气体种类。涂层技术可以使吸收增强因子的光谱随甲烷浓度的增加而线性变化，并且灵敏度可以达到0.794 nm /％。传感器简单可靠，线性度好，