两层镀膜长周期光纤光栅传感器的特性研究

摘要

以光纤光栅耦合模理论为基础,提出一种两层镀膜长周期光纤光栅传感器的结构模型,一层是在光纤包层外镀的铜金属薄膜,另一层是在铜薄膜外再镀一层敏感薄膜.对该结构模型的模场特性和透射特性进行分析和模拟,明确了薄膜参数对其透射特性的影响.该结构模型既可以利用敏感膜折射率随外界环境变化而改变的特性,也可以利用金属膜层进行温度和应变调节来改变谐振波长的特点,为高灵敏度长周期光纤光栅传感器的优化设计提供了理论依据.%A kind of two-layer coated long period fiber grating sensor structure model is proposed based on fiber grating coupling theory. One layer is copper metal film plated on the outer cladding of fiber, another layer is sensitive film coated on the layer of copper film. Characteristics of the mode field and transmission of the two-layer coated long period fiber grating are analyzed and simulated. The influences of film parameters on the characteristics of the transmission are studied. The characteristics of refraction of sensitive film change with environmental and metal film is used, resonant wavelength is adjusted through temperature and strain. The results can provide theoretical basis for optimal design of high sensitivity long period fiber grating sensor.