基于双磁环调控并联磁流体双腔的高精度光纤电流传感器研究

Magnetic/current sensors based on new functional material of magnetic fluit have attracted considerable domestic and foreign attentions due to their superior magneto-optic character. However, the existing fiber current sensors based on magnetic fluit has the disadvantages of cross-sensitivity to temperature, low sensitivity to magnetic field，or low stability，and so on. Its application is seriously restricted in the future smart grid. To solve the problems, we propose a fiber micro-cavity (FMC) which can automatically compensate the temperature. The current sensitivity can be greatly improved by the Vernier effect of double cavities and magnetic gathering of two magnetic loops. Firstly, we will research on the strain of FMC caused by temperature, and compensate the temperature by using the strain to balance out thermo-optic effect of magnetic fluit. Secondly, we will built the four-beam interference model of parallel double FMCs, analyze the interference and the coupling between beams, and research the relationship between Vernier effect and the structure of double FMCs, to provide theoretical basis for the design of double FMCs. Finally, we will research the performance of high efficient electromagnetic control and the mechanism of spectral shifts of double FMCs in the opposite direction, to provide theoretical basis for high efficient electromagnetic conversion and high sensitive demodulation of parallel double FMCs. In a word, our research has important theoretical and practical significance in improving the development of fiber current sensor with new high performance based on magnetic fluit.

基于新型材料磁流体的光纤磁场/电流传感器以其优越的磁光性能引起国内外广泛关注，然而现有的磁流体光纤电流传感器存在温度交叉敏感、灵敏度低或稳定性和可靠性差等缺点，严重制约了其在未来智能电网等工程上的应用。为此，本课题提出了可温度自动补偿的并联光纤微腔结构，该结构分别利用双腔游标效应提高磁场响应和双磁环聚磁特性增大电磁转化效率，可大幅提升电流测量灵敏度。项目首先分析光纤微腔热应变规律，构建热应变与热光效应相互抵消的温度补偿结构；其次，建立并联双腔四光束干涉理论模型，分析各光束间的干涉与耦合，研究并联双腔游标效应随双腔结构参数的变化规律，在此基础上设计磁场高增敏的并联磁流体双腔结构；最后，研究双磁环系统高效电磁调控特性以及双腔干涉谱相向频移机理，为实现高效电磁转化及高灵敏度双腔解调提供理论依据。因此，本项目的研究对促进新型的高性能磁流体光纤电流传感器的发展具有重要的理论和实际意义。

针对磁流体光纤电流传感器存在温度交叉敏感、灵敏度低等问题，本项目突破传统信号光调制和解调的思维方式，从光纤微腔传感机理和磁路定理出发，提出了基于双磁路系统调控磁流体并联双腔的电流传感方案。构建了并联双腔多光束干涉模型，揭示了并联双腔结构干涉谱包络产生机理和游标效应增敏机理；构建了双磁路调控模型，通过加载反向偏置磁场，实现了双磁路内被测磁场反向调控，揭示了电流-磁场高效转化机理和磁流体并联双腔温度补偿机理；研究了双磁路系统对磁流体并联双腔的调控特性，实验验证了该电流传感方案的有效性。因此，本项目的研究成果解决了现有磁流体光纤电流传感器温度交叉敏感、灵敏度低等缺陷，对促进新型的、高性能的光纤电流传感器的开发和应用具有重要的理论和实际意义。