磁光型光纤电流传感器中的磁畴效应及非线性响应研究  

Magnetic Domain Effects and Nonlinear Responses of Magneto-optic Fiber Current Sensors

作　　者：梁志状 韩群 唐语良 张腾 程振洲 LIANG Zhizhuang;HAN Qun;TANG Yuliang;ZHANG Teng;CHENG Zhenzhou(Laboratory for Optoelectronic Technology and Optical Fiber Sensing,School of Precision Instrument and Opto-electronics Engineering,Tianjin University,Tianjin 300000,China)

机构地区：[1]天津大学精密仪器与光电子工程学院光电技术与光纤传感实验室,天津300000

出　　处：《光子学报》2023年第8期42-51,共10页Acta Photonica Sinica

基　　金：国家自然科学基金(No.621775179);天津市自然科学基金(No.22JCYBJC00090)。

摘　　要：限制磁光晶体型光纤电流传感器实用化的主要因素为磁光响应的非线性问题。其中包括维尔德系数随温度变化导致的磁场与温度交叉串扰问题。为进一步提高传感器精度,对磁光晶体非线性响应的来源进行了理论和实验研究。研究结果表明,在恒温条件下,磁光响应符合磁畴衍射模型,通过理论推导证明了非线性误差与磁光晶体的衍射无关,而与两路光电探测器的电压转换系数失配和起偏器与偏振分束器光轴夹角的装配误差有关。采用二次多项式拟合可以有效减小解调误差,提高传感器的精度。本文对高精度磁光型光纤电流传感器的研究及其实用化具有重要意义。With the rapid increase of electrical power demand,the voltage level of power grid also improved.The traditional current transformer is difficult to meet the needs of power grid because of its easy saturation,poor insulation,narrow frequency band,etc.The optical fiber current sensor can solve these problems.Therefore,it has wide application prospects in power monitoring and smart grid construction.However,the nonlinear response of magneto-optical crystal is the main factor that limits the application of the magneto-optic fiber current sensor.Nowadays,research on the nonlinear error of the Fiber Optical Current Sensors(FOCS) mainly focuses on the nonlinear dependence of the Verdet coefficient of the Magneto-optical(MO) materials on the external temperature.The change of Verdet coefficient will lead to the crosstalk of magnetic field and temperature,which is one of the main factors limiting the practical application of the FOCS.Nevertheless,when the temperature is fixed,the output signals of the MO materials is also not changed linearly with change of the external magnetic field.To improve the accuracy of the sensors,we studied the source of the nonlinear response of the MO crystal theoretically and experimentally.In this paper,we demarcated the output curve of garnet crystal from no magnetic field to saturated magnetic field.Through simulation and experiment,we proved that the nonlinear response of MO fiber optical current sensor is caused by the diffraction characteristics of magnetic domain of the MO material.The model of magnetic domain effect proposed by us conforms to the output response of the MO sensors.Through the dual-channel demodulation method,we can calculate the intensity of the output light through the 45° polarization beam splitter according to Malus law.And we obtain the Faraday rotation angle according to the demodulation algorithm of difference division sum.The theoretical results show that the influence of nonlinear error caused by magnetic domain effect can be ignored with the method of the tw

关 键 词：光纤传感 光纤电流传感器 磁光晶体 磁畴效应 非线性补偿 

分 类 号：O438[机械工程—光学工程]