基于光纤光栅的磁场测量新方法  

Measurement for Magnetic Field with Fiber Grating

作　　者：彭晖[1] 苏洋[1] 李玉权[1] 陈鹏[1] 吴伟磊[1] 朱英勋[1] 

机构地区：[1]解放军理工大学通信工程学院,江苏南京210007

出　　处：《光学学报》2008年第9期1717-1722,共6页Acta Optica Sinica

基　　金：国家自然科学基金(60472007);国家自然科学基金青年科学基金(60502003)资助课题

摘　　要：提出了一种基于光纤光栅中法拉第效应和测量偏振相关损耗的直接测量磁场的新方法,给出了理论分析和实验结果。当有外加磁场时,光纤光栅中的法拉第效应使两个圆偏振光的传播常量改变,从而导致光纤光栅的偏振相关损耗的变化。仿真结果表明,外加磁场与偏振相关损耗峰值在一定的测量范围内存在线性关系,测量结果对温度变化不敏感。分析了光栅的参量对测量性能的影响。实验中得到该方案测量磁场的灵敏度为7.8e-6dB/Gs,利用现有精度为10-5dB的光矢量分析仪得到最小可测磁场为2 Gs。实验与理论吻合较好。A new magnetic field measurement method based on Faraday effect and measurement of polarizationdependent loss （PDL） in fiber grating was proposed and analyzed in theory and experiment. When the external magnetic field is applied, the transmission constants of the two circularly polarized lights in fiber grating will be changed by the Faraday effect, and so does the PDL of fiber grating. The simulations show there is a linear relationship between the peak value of PDL and magnetic field in a certain range. Moreover, this method is insensitive to temperature. The influence of parameters of grating on measurement performance was analyzed. The measurement sensitivity is 7.8e^- 6 dB/Gs and the precision is 2 Gs using the optical vector analyzer with 10 s dB precision in experiment, which agree well with the theoretical analysis.

关 键 词：光纤光栅 磁场测量 法拉第效应 偏振相关损耗 温度不敏感 

分 类 号：TP212[自动化与计算机技术—检测技术与自动化装置]