基于FBG偏振相关损耗的二维力测量

Measurement of two-dimensional force based on FBG polarization-dependent loss

采用耦合模理论分析了光纤布拉格光栅(FBG)反射偏振相关损耗(RPDL)峰位置与轴向力和侧向力的关系,进而通过相关灵敏度系数矩阵,应用单根FBG实现对轴向力和侧向力的同时测量,从而得到结构体内部二维力及二维应变信息。实验测得,(RPDL)左峰和右峰的轴向力灵敏度分别为0.986 2nm/N和0.986 7nm/N,侧向力灵敏度分别为0.007 1nm/N和0.000 5nm/N,轴向力和侧向力测量精度分别为±0.01N和±0.51N。本文方法核心传感元件简单,稳定性好,精度高,易于实现,为检测材料内部结构变化提供了新方法。

According to the coupled-mode theory, different properties of reflective polarization-dependent loss （RPDL） of fiber Bragg grating （FBG） to axial and lateral forces are analyzed. Based on the relevant sensitivity coefficient matrix, the axial and lateral forces can he demodulated by a single fiber Bragg grat- ing simultaneously, by which the two-dimensional force and strain information in the structure can be demodulated. The experimental axial force sensitivity coefficients of left peak and right peak of RPDL are 0. 986 2 nm/N and 0. 986 7 nm/N,respeetively. Lateral force sensitivity coefficients achieve 0. 0071 nm/ N and 0. 000 5 nm/N, respeetivelies. The accuracies of axial and lateral forces can reach ±0.01 N and ± 0. 51 N,respectively. The method has several advantages,such as simple core component,high stability, high accuracy and easy realization. It provides a new method to test the changes of structure internal information.