两类典型光纤型SPR传感器的理论模型比较

针对基于SPR效应的两类典型光纤型传感器:传统型包层腐蚀的镀金属多模光纤传感器、新型镀金属单模光纤光栅传感器，指出其不同的SPR模型处理方法及传感特性。首先，根据传统型SPR光纤传感器的结构特点，利用平板SPR理论给出反射谱特性，同时指出并证明薄膜光学理论在平板SPR结构中与平板SPR理论的等价性。其次，针对新型SPR光纤光栅传感器结构特点，依据模式耦合思想，结合SPW模式特征，提出了光纤光栅SPR结构的理论处理方法，得到了镀金膜三包层LPFG结构的透射谱。最后，对基于SPR效应的两类典型光纤型传感器的传感特性进行了比较分析，结果表明，两类传感器对环境折射率均具有较高的分辨率，但新型光纤光栅SPR传感器的分辨率高出传统SPR光纤传感器3个数量级。

Comparison of theory model for two typical optical fiber sensors based on SPR

Aiming at two kinds of typical optical fiber sensor based on SPR effect, which are traditional multimode optical fiber sensor coated with metal film whose cladding is corrosion, and a novel single-mode optical fiber grating sensor coated with metal film, SPR theoretical model and processing method were presented. First of all, according to the structural characteristics of traditional fiber SPR sensor, using the theory of plate SPR effect, reflection spectra of this sensor were given. Meanwhile, it is pointed out and proved that thin film optical theory and theory of SPR are equivalent in the flat structure. Secondly, according to the structure characteristics of novel SPR fiber grating sensor based on mode coupled theory, combined with the feature of SPW mode, the theory processing method of SPR in fiber grating was put forward, the transmission spectra of triple-cladding LPFG coated with gold film were given. Finally, the comparative analysis on the sensing characteristic of two kinds of typical optical fiber sensor based on the SPR effect was carried out, and the results show that two kinds of structure have high resolution of environment refractive index, but the resolution novel optical fiber grating SPR sensor is higher 3 orders of magnitude than that of traditional fiber SPR sensor.