针对光子晶体光纤折射率传感器外表面金属薄膜易氧化的问题, 文章提出一种新型结构的光子晶体光纤折射率传感器, 该光子晶体光纤内部空气孔呈螺旋轨迹排列。光纤外表面进行双层膜涂覆, 使用银作为表面等离子体共振材料涂覆在光子晶体光纤的外表面, 在银膜外又涂覆了一层15 nm厚度的氧化锌薄膜以防止银被氧化。在各向异性的完美匹配层边界条件下, 利用全矢量有限元法对传感器特性进行了数值仿真, 结果表明: 该传感器所能测量的折射率范围为1.30~1.36, 灵敏度最高可达5 200 nm/RIU, 分辨率可达1.92×10-5RIU。

Aiming at the problem of easy oxidation of metal film on the outer surface of Photonic Crystal Fiber (PCF) refractive index sensor, a new structure of PCF refractive index sensor is proposed. The air holes of the PCF are arranged in a spiral track. Double coating is on the outer surface of the PCF. The silver is coated on the outer surface of the PCF as a Surface Plasmon Resonance (SPR) material, and a 15 nm thin ZnO film is coated on the silver film to prevent the metal from being oxidized. The properties of this sensor is analyzed by the full vector finite element method with the boundary condition of anisotropic perfectly matched layer. Results show that the maximal sensitivities of the sensor reach 5 200 nm/RIU and the resolution reach 1.92×10-5 RIU when refractive index is in the range of 1.30 to 1.36.