基于磁流体和单模-锥形多模-单模光纤的高灵敏度无热化全光纤电流传感器

Current detection is an important part of power system for electrical energy measurement, relay protection, system diagnosis and monitoring analysis. The current detection technology with high measuring sensitivity and good operating reliability is necessary in order to realize security and economic operation in power system. To meet the above requirements, this project aims to study the basic and critical issues of the athermal current sensor based on magnetofluid and single-mode-tapered multimode-single-mode fiber (STMS) structure with high sensitivity. Using the beam propagation method, the mode field distribution and its evolution process of each mode of the composite waveguide is simulated to realize a few-mode or even two-mode interference. Since the effective index difference changing with temperature equals to zero in a special case, the structure design can be optimized to obtain high temperature stability. Through the polarization controllable micro/nano optical fiber drawing device, a STMS structure can be prepared with micro/nano functional size to achieve high measurement sensitivity. We will thoroughly research the self-assembly process of nano magnetic particles in an external magnetic field. Nano magnetic particle chains mechanism will be explored. Experimental method to improve the response speed of the magnetic nano particles will be found. Based on the above work, an all-fiber current sensor with practical application prospect will be developed, which should speed up the nationalization of all-fiber current sensor.

电流检测是电力系统电能计量、继电保护、系统诊断与监测分析的重要组成部分。为了保证电力系统的安全和经济运行，需要测量灵敏度高，运行稳定性好的电流检测技术。本项目针对上述需要，开展基于磁流体包覆单模-锥形多模-单模光纤(STMS)复合波导的高灵敏度无热化电流传感器的基础理论和关键技术研究。运用光束传播法模拟复合波导中各模式的模场分布与演化过程，从而实现少模甚至双模干涉；利用双模干涉波导中两个传输模式的有效折射率差的温度变化系数存在零点的特点，优化结构设计，使传感器干涉波长不随温度漂移，获得高的温度稳定性；通过低损耗偏振可控微纳光纤拉伸装置制备功能尺寸达到微纳尺度的STMS结构光纤，获得高测量灵敏度；深入研究磁流体纳米磁性颗粒在外加磁场作用下的自组装过程，探索纳米磁性颗粒的成链机理，实验上提高纳米磁性颗粒的响应速度。研制一种有实用化前景的全光纤电流传感原型器件，加速全光纤电流传感器的国产化进程。

项目针对电力系统对电流检测技术测量灵敏度高，运行稳定性好的需求，开展全光纤电流传感器的基础理论和关键技术研究，通过弯曲锥形微纳光纤和磁流体薄膜形成的复合波导结构设计，在微纳尺度下实现整个通道范围内快速可调且性能稳定的新型光纤梳状滤波器件。在光纤锥形区引入弯曲结构，有效激发两个低阶模式，获得高消光比同时抑制插入损耗；优化光纤束腰区直径和磁流体薄膜参数，使两个传输模式有效折射率差随环境温度的变化率近似为零，获得高的热稳定性；结合微纳光纤拉伸工艺和光纤表层薄膜技术，实验制备并研究该滤波器的磁光调制特性，由此研制一种具有广泛应用前景的新型微纳光电子器件，为实用化微纳器件的研究提供新思路。项目在以下三个方面开展了系统的研究：一、对低损耗高温度稳定性双模干涉导波结构进行了设计和分析，对弯曲锥形微纳光纤结构中涉及的各种参数，尤其是其锥形过渡区的弯曲半径、腰区的直径和长度等参数对其干涉特性的影响进行了研究；二、对器件制备所需的材料进行了遴选，对器件制备所涉及的制备工艺进行的研究，相关工艺包括薄膜制备工艺和微纳光纤制备工艺；三、围绕成本低、体积小、调谐范围宽和调谐灵敏度高的可调谐光纤滤波器开展了研究，包括研究其温度特性和电光特性，取得了一些相关成果。该类光纤器件在湿度检测、气体传感、微粒检测方面有一定的应用。