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基于三包层长周期光纤光栅模型,研究了包层表面涂覆一层溶胶凝胶气敏薄膜的长周期光纤光栅化学传感器的灵敏度Sn与薄膜光学参量(折射率n3和厚度h3)和光纤光栅结构参量(光栅周期、折变量和光栅长度)之间的关系。采用最优化数值方法,找到了获得高灵敏度所需的最佳膜层光学参量和光栅结构参量。理论计算表明,该类型传感器对膜层折射率的测量分辨率高达10-8。实验上制作了对乙醇气体敏感的传感器,并证实了传感器结构优化的必要性。
Based on the three-layer long-period fiber grating model, the sensitivity of the long-period FBG chemical sensor coated with a sol-gel gas sensing film on the surface of the cladding was studied. The results show that the sensitivity of the sensor with the optical parameters of the film (refractive index n3 and thickness h3) Relationship between structural parameters (grating period, fold change and grating length). Optimum numerical method was used to find the optimal optical parameters and grating structure parameters for high sensitivity. Theoretical calculations show that this type of sensor can measure the refractive index of the film up to 10-8. Experiments were made on ethanol gas sensor sensitivity, and confirmed the need for structural optimization of the sensor.