一种基于径向偏振解调的线性光学电流传感器

提出了一种基于径向偏振解调的线性光学电流传感器。采用集磁式传感头，由两块导磁板将气隙磁场引出，直通式光路由通光孔经过气隙磁场，不需要反射棱镜，根除了反射相移，有利于改善传感器的稳定性。采用径向偏振光栅将法拉第旋转角转换为环形光斑的同步转动，由四象限探测器对光斑定位得到待测电流。经理论分析和实验验证，传感器的测量模式与光强无关，法拉第旋转角测量范围为43，测量准确度0.2S级。

A linear optical current transducer based on radial polarization demodulation

A linear optical current transducer (OCT) based on radial polarization demodulation was proposed. A magnetic concentration ring with an air gap was selected as the sensing head, in which two magnetizer plates were used to lead out the magnetic field of air gap, and the straight optical path passed through the air gap by light apertures. The reflecting prism was not needed so that the reflection-induced retardation was eliminated, which helped to improve the stability of the transducer. A radially polarized grating was employed to convert the Faraday rotation angle into the rotation of a circular facula, which was detected by a four-quadrant detector, and then the measured current could be obtained after signal processing. The theoretical analysis and experimental results show that this new OCT has a measurement range of 43 in Faraday rotation angle and the advantage of optical power independent, meeting the national standard of 0.2S accuracy class.