材料色散对LPFG双峰谐振效应特性的影响

采用严格的耦合理论，研究了长周期光纤光栅各层材料色散对双峰谐振效应的影响，指出芯层和包层材料色散必须同时考虑才能切实地符合实际情况.分析了材料色散对不同膜层参数下双峰谐振LPFG透射特性的影响，模拟计算了材料色散计及与否时的双峰谐振波长，两种情形下两峰偏差值分别约在1.5—2 nm和6.5—7.5 nm浮动.最后，讨论了材料色散对双峰LPFG传感器灵敏度的影响.结果表明，此类传感器对膜层折射率的分辩率高达10^-8，计及材料色散后的等高线图可为传感器灵敏度设计提供精确的参数选择组合. 关键词： 材料色散 长周期光纤光栅 双峰谐振

The influence of the material dispersion on the dual-peak resonance effect

Based on rigorous coupling theory，the influence of the dispersion of the core，cladding，film and surrounding material on the dual-peak resonance effect is studied. The result shows that the theoretical model which considers both the core and cladding material dispersion is necessary and feasible. Further，the influence of the material dispersion on the transmission characteristics of LPFG is analyzed for different film parameters. The deviation value between the dual resonant peaks is calculated before and after considering the material dispersion. The result shows that the deviation value is 1.5—2 nm and 6.5—7.5 nm, respectively. Finally，the influence of the material dispersion on the sensor sensitivity is studied for the dual-peak LPFG sensor. The result indicates that the minimum resolution for the film refractive index is 10^-8，and the contour line figure after considering the material dispersion supplies accurate parameter combinations in the design of this kind of sensor.