光纤倏逝波传感器探针灵敏度分析  

Analysis of the Sensitivity of Optic Fiber Evanescent Wave Sensors

作　　者：李维[1] 许雪梅[1] 刘茜倩[1] 吴爱军[1] 叶俊华[1] 王华[1] 吴建好[1] 夏辉[1] 

机构地区：[1]中南大学物理科学与技术学院,长沙410083

出　　处：《光电子技术》2008年第2期81-85,88,共6页Optoelectronic Technology

基　　金：国家自然科学基金资助项目(60708014);中南大学理科发展基金项目(206001083)

摘　　要：针对直线型光纤探针结构特点,从倏逝波场能量的角度对探针的灵敏度进行理论建模,推导出探针平均倏逝波吸收系数的表达式。在此基础上从探针锥型长度与纤芯半径的匹配关系、入射角度、溶液折射率这几个方面对灵敏度的影响进行实例计算。计算结果表明:在探针长度一定时,合理的选择锥型长度与纤芯半径能有效地提高探针灵敏度,实例中最高有接近69倍的差别。同时入射角越靠近全反射角,溶液折射率越大,则探针的灵敏度越高。最后通过实验研究表明,实验结果与理论计算具有一致性。Aiming at the structural characteristics of linearly fiber, the sensibility of sensors model has been build base on evanescent. The expression for an effective evanescent-absorption coefficient has been derived form model. The effects of taper geometries incident angle and the refractive indices of absorbing fluid are considered. The result shows that choosing a suitable proportion is important to enhance sensitivity when the length of probe is fixed on. In our calculate the highest sensibility of probe is 69 times bigger than the weakest one. The sensibility of sensors is also increased when the incident angle approaches critical angle and the refractive index of absorbing fluid is increased. Finally an experiment has carried out, which shows that the experiment results are conforming to the theory calculate.

关 键 词：传感器 光纤 倏逝波 探针 灵敏度 

分 类 号：TP212[自动化与计算机技术—检测技术与自动化装置]