LPFG 镀层参数对其折射率传感特性的仿真分析

长周期光纤光栅在传感测量领域具有防爆、防磁、抗干扰等优点,且对周围介质折射率的变化敏感,适用于矿井、油田等易燃、易爆、强电磁干扰环境及具有毒性、腐蚀性等不宜接触的液体的折射率测量。本文采用在长周期光纤光栅包层外沿径向镀一金属薄层的方式,从长周期光纤光栅传感原理着手,利用三包层模型的本征方程,并借助MATLAB进行方程求解和仿真分析,讨论了包层模序数、光栅周期、膜层厚度等参数与谐振峰中心波长偏移的关系。为合理选择光栅结构参数、制作符合要求的长周期光纤光栅用于折射率传感测量提供了依据。

Influence of LPFG plating parameters on sensing properties of its refractive index

Long-period fiber gratings(LPFG) can be used in the field of communication and sensing,especially measurement of flammable,explosive,EMI environment and caustic,venenous liquid because of their excellent properties such as anti-magnetism,anti-noise,anti-explosion and so on.A metal film was plated on the surface of LPFG cladding.Based on LPFG sensing principle and its intrinsic equation,the modeling and simulation were carried out,and the influences of the parameters such as number of mode,period of LPFG,film thickness on harmonic peak wavelength were discussed.The obtained conclusion can provide a reference for selecting rational structure parameters of LPFG used for sensing measurement of refractive index.