光纤布拉格光栅的折射率传感研究

摘要

The refractive index sensor is prepared by using fiber Bragg grating,and the relationship between the sensor sensitivity of fiber Bragg grating refractive index and cladding diameter is mainly studied.According to theoretical a-nalysis,when the grating cladding diameter is smaller,the effect of the surrounding refractive index change on Bragg wavelength shift is greater,and this makes the change of LD optical power reflected by the fiber Bragg grating more ob-vious.Hydrofluoric acid solution is adopted to corrode the grating cladding,and then the refractive index sensor of fiber Bragg grating with different cladding diameters can be acquired.The experimental results show that the grating sensing refractive index range will be narrowed when cladding diameter is reduced,but its refractive index sensing sensitivity will increase.%采用光纤布拉格光栅制备折射率传感器，研究光纤光栅的折射率传感灵敏度与其包层直径之间的关系。理论分析可得，光栅包层直径越小，Bragg 波长的偏移量随环境折射率变化的影响越大，这样就能使实验中光栅所反射的 LD 光功率变化（传感灵敏度）越明显。利用氢氟酸溶液腐蚀光栅包层的方法，得到不同包层直径的光纤 Bragg 光栅折射率传感器。实验指出，包层直径减小时，光栅可传感的折射率范围会缩小，而其折射率的传感灵敏度却会增大，如包层直径为8．9μm 时，折射率的检测范围为1．3872～1．4730，其最大灵敏度值达到了224．0320 dBm ／RIU。