基于磁流体包覆复合光纤光栅的磁场传感器研究

发布时间：2018-10-23 15:05

【摘要】：随着物联网应用的蓬勃发展,当前研究人员正在采取相关方法与技术不断提高智能化产品与设备的设计系统的性能。光纤光栅传感器由于抗干扰、测量精度高、体积小、响应灵敏等优点,其传感机理和结构设计得到越来越多的科研人员关注和研究。本文将复合光纤光栅与磁流体的特性相结合,提出磁场传感测量的设计计划与方案。主要围绕减小包层直径的布拉格光纤光栅、倾斜长周期光纤光栅和普通长周期光纤光栅级联多模光纤等结构,结合磁流体在不同磁场强度下具有折射率可调谐特性,就其在光纤磁场传感中的应用进行了深入的理论和实验研究。本文主要工作如下:(1)提出一种基于磁流体包覆减小包层直径的布拉格光纤光栅的磁场传感器,通过腐蚀特意改变布拉格光栅的包层直径,使得光纤中的基模模式与环境介质相互作用,并且从布拉格光栅谐振峰和包层模式谐振峰进行实验和分析,得到波长漂移量与磁场强度大小有很好的响应关系。(2)利用高频CO2激光器写制倾斜长周期光纤光栅,该光纤光栅不仅能够将光从纤芯模耦合到同向传输的包层模中,而且能够与非对称的包层模式发生耦合。实验上得到LP0m和LP1m模式分别对应的谐振峰。随着外界磁场强度变化时,深入研究磁流体包覆时该结构的光谱特性,其传输损耗的变化大小与磁场的强度有很好的线性关系。(3)利用HF溶液腐蚀并去掉多模光纤(105/125)的包层,并将其与长周期光纤光栅熔接级联。实现了一种对温度和磁场双参数同时测量的传感测量器件。利用长周期光栅的模式耦合与多模光纤的干涉这两种不同耦合机制获得双参数传感矩阵,其能够有效解决磁场传感时存在的温度交叉干扰问题,并从传感机理进行深入研究。该器件能够有效解决磁场传感时存在的温度交叉干扰问题,同时得到对宽范围磁场进行探测的传感特性。
[Abstract]:With the rapid development of Internet of things (IoT) applications, researchers are adopting relevant methods and technologies to improve the performance of intelligent product and equipment design system. Because of the advantages of anti-interference, high measurement precision, small volume and sensitive response, the sensing mechanism and structure design of fiber grating sensor have been paid more and more attention and research by researchers. In this paper, the characteristics of composite fiber grating and magnetic fluid are combined, and the design plan and scheme of magnetic field sensing measurement are put forward. The fiber Bragg gratings with reduced cladding diameter, inclined long-period fiber gratings and ordinary long-period fiber gratings have cascaded multimode fibers, and the magnetic fluid has tunable refractive index characteristics under different magnetic field intensities. Its application in optical fiber magnetic field sensing is studied theoretically and experimentally. The main work of this paper is as follows: (1) A magnetic field sensor based on magnetic fluid coating fiber Bragg grating (FBG) with reduced cladding diameter is proposed. The fundamental mode in the fiber interacts with the ambient medium, and the experiment and analysis are carried out from the Bragg grating resonant peak and the cladding mode resonant peak. It is found that the wavelength drift has a good response to the magnetic field intensity. (2) the inclined long-period fiber grating is fabricated by using a high-frequency CO2 laser. The fiber grating can not only couple the light from the core mode to the cladding mode in the same direction. And it can be coupled with asymmetric cladding model. The resonance peaks corresponding to LP0m and LP1m modes are obtained experimentally. With the change of magnetic field intensity, the spectral characteristics of the structure are studied in depth. The change of transmission loss is linearly related to the intensity of magnetic field. (3) the cladding layer of multimode fiber (105 / 125) is corroded and removed by HF solution. And it is fused with long period fiber grating in cascade. A sensor device for simultaneous measurement of two parameters of temperature and magnetic field is realized. Two-parameter sensing matrix is obtained by using two different coupling mechanisms of long-period grating mode coupling and multi-mode fiber interference. It can effectively solve the problem of temperature cross-interference in magnetic field sensing, and the sensing mechanism is deeply studied. The device can effectively solve the problem of cross-interference of temperature in magnetic field sensing, and obtain the sensing characteristics of detecting wide magnetic field at the same time.
【学位授予单位】：天津理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN253

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