光纤光栅传感网络技术研究与应用

【作者】 刘波；

【导师】 牛文成；

【作者基本信息】 南开大学 ， 光学， 2006， 博士后

【摘要】 传感技术是信息技术的重要支柱。而光学传感,尤其是光纤传感技术,是近些年来发展最为迅速的传感技术之一。由于光纤具有许多优良的特性,因此其在复杂恶劣环境中,成为不可替代的传感器件。光纤光栅是一种新型的光无源器件。它是利用光纤材料的光敏特性在光纤的纤芯上建立的一种空间周期性折射率分布,其作用在于改变或控制光在该区域的传播行为方式。光纤光栅的出现,使许多复杂的全光纤通信网络和传感网络成为可能,极大地拓宽了光纤技术的应用范围,并由此产生了许多重要的应用。作为光子研究领域的一种新兴技术,以光纤和光纤光栅为基本传感器件的传感技术近年来受到普遍关注,各国研究者积极开展有关研究工作。本报告结合国家863重点项目“光纤光栅传感系统中的关键技术及实用化研究”和天津市重点攻关项目“工程化光纤光栅传感器及其网络解调系统设备研制”等,并考虑当前光纤和光纤光栅传感网络技术的发展方向和主要问题,主要对光纤和光纤光栅的传感技术、解调技术以及网络技术进行了理论和实验的研究工作。报告的主要内容有:1.以光纤光栅作为传感器件,对光纤光栅的增敏和减敏技术进行了研究,开发出一套完整的封装工艺,并研制开发了多种适合工程使用的光纤光栅传感器。2.采用可调谐法布里-珀罗滤波器作为核心解调器件,利用并行解调方案,设计并制作实现了工程化光纤光栅传感网络解调设备(GCW型光纤光栅传感网络解调系统),实现了光纤光栅传感器网络的波长解调,性能优良,被鉴定为国际先进水平。3.对倾斜光纤光栅进行了理论分析。在柱坐标系下推导了倾斜光纤光栅的传输公式并进行了理论模拟。采用倾斜光纤光栅作为核心解调器件,采用边沿检测的方法,实现了800nm波段的倾斜光纤光栅波长解调系统,并利用该系统进行了温度和应变的传感的实验。4.针对一般可调谐激光器输出功率随波长变化的问题,采用自动功率控制方法,通过在掺铒光纤环行腔激光器内加入功率负反馈,设计并实验成功一种均衡功率的C+L波段的掺铒光纤可调谐激光器。波长调谐范围为87nm(1525-1612nm),覆盖了整个C+L波段。输出激光功率0.7mW,3dB带宽为0.26nm,各波长激光的边模抑制比高于55dB。5.在光纤传感方面,对各种光纤围栏的可行性技术进行了探讨与分析。同时,利用M-Z干涉技术,设计并实现了一种实用的光纤围栏系统,进行了单点和多点扰动的实验。更多还原

【Abstract】 Fiber gratings are attracting considerable interests in applications. They are new type of passive optical components, which are based on the periodical distribution of refraction index in fiber core. Fiber gratings have several distinguished advantages over normal fibers. Because of their intrinsic nature and inherent wavelength-encoded operation, fiber gratings are utilized as sensing elements in recent years. The relevant reports have been appealed much attention throughout the world.Encoding the information on the measurand in a wavelength form has been caused extensively focus. The most important advantage is that wavelength is an absolute parameter and thus does not depend on loss of the system or fluctuation of the source power. Most of today’s demodulation techniques rely on optical filtering method, such as bulk optical edge filters, scanning fiber Fabry-Perot filters, WDM fiber couplers, acousto-optic tunable filters and Mach-Zehnder filters.In this report, we mainly focus on the research and realization of fiber Bragg grating networks, including the principles and experiments of sensing and demodulation techniques. The contents are listed as follows:1. Generally introduce the sensing technique, especially the present situation and development of fiber and fiber Bragg grating sensor technique. The fundamental theory of fiber grating is also demonstrated. The basic principle of fiber Bragg grating sensor and demodulation and multiplex technique can be found in this dissertation.2. Using the fiber grating as the basic sensor unit, we design several kinds of FBG sensors which are suitable for application. Moreover, the design principle, the system structure as well as the test results are demonstrated in detail.3. We designed and realized a high-speed sensor multiplexing network system based on the F-P tunabled filter. The high-speed wavelength demodulation of fiber Bragg grating sensor has been turned into practice. The system principle is introduced and analyzed in this dissertation. The system is designed as an all-fiber system. It realized the high-speed wavelength-division-multiplexing demodulation of fiber grating sensor. 4. Some theorical works on tilted fiber Brag grating is presented in this paper. And more, we firstly build the demodulation system based on TFBG in the world. The principle and structure are introduced in detail. And the experimental results are also presented.5. In this report, a power-equilibrium tunable C+L band Erbium-doped fiber lasers is proposed and demonstrated. The laser is based on Erbium-doped fiber ring, and a F-P filter incorporated with a tunable bandpass filter in the ring. At the same time, the Auto-Power-Control (APC) technique is used to proportion the output power of the laser. The laser has wide tunable range from 1525nm to 1612nm, and the sidemode suppression ratio is more than 55dB. The output power variation is less than +/-0.1dB over the running range.6. At the end, we discuss the feasible techniques for fiber fence. Using M-Z interferometer, we build and realize a practical fiber fence system. The principle and structure and also the experimental results are presented and discussed.更多还原