【作者】 董兴法；

【导师】 董孝义； 开桂云；

【作者基本信息】 南开大学 ， 光学， 2005， 博士

【摘要】 世界已经跨入信息时代,光子作为信息的又一种载体越来越显示了它的显著地位。光纤作为信息传输的通道正在得到广泛地应用,各种类型的光纤系统及光纤器件共同构筑了和改善着我们这个社会信息交流的平台,显示了不可替代的重要性。光纤光栅是纤芯折射率沿光纤轴线呈周期性变化的一种光纤结构,它标志着近年来继光纤以后的又一座里程碑。目前,以布喇格光纤光栅(FBG: fiber Bragg grating)为传感主体的传感器已成为研发主流。这种传感器适于在高温、腐蚀性或危险性环境中使用。在大型建筑和油井等特殊场合的安全监测方面具有极为广泛的应用前景。目前,已报道的光纤光栅传感器可以检测的物理量有:温度、应变、压力、位移、压强、扭角、扭矩(扭应力)、加速度、电流、电压、磁场、频率、浓度、热膨胀系数、振动等,其中一部分光纤光栅传感系统已经实际应用。本论文主要以布喇格光纤光栅为研究对象,对其传感技术、解调技术以及网络技术进行了理论和实验的研究。主要内容有:1.概括介绍了光纤传感和光纤光栅传感技术的发展现状。分析了以光纤光栅作为基本传感器件的原理,说明了不同成栅方法的特点,概述了光纤光栅传感器的解调和复用技术。2.从耦合模理论出发,论述了具有不同折射率结构的光纤光栅所表现的传输谱及其应用范围。以均匀Bragg光纤光栅、长周期光纤光栅为典型,简要推导了传输谱的中心波长、反射率、3dB带宽等参数的数学表述,说明了它们与折射率调制因素的关系。从一般光纤传感器到当今广泛研究的FBG传感器,研究了它们的组网原理,讨论了限制传感器网络中点数设置的关键问题。3.从光纤光栅传感技术的关键点入手,系统阐述了单点解调方法、组网方法及复用系统的解调方法。这些包括马赫-泽德、迈克尔逊等干涉型解调方案以及法布里-珀罗可调谐滤波器、边沿滤波、匹配光纤光栅滤波等滤波型解调方案。分析了在光纤光栅传感系统阵列化应用时的关键复用技术,如波分复用(WDM)、时分复用(TDM)、空分复用(SDM)等技术的组合解调方法。同时,还对传感系统中光电检测的关键技术以及光源技术进行了探讨。4.从光纤光栅交叉敏感物理模型出发,引入光纤光栅的交叉关联分析方法,指导高性能传感器的设计。首次提出并设计了用于结构损伤诊断的实用型光纤光栅传感器,并获得专利授权;研究了应用F-P半导体激光器和FBG振动传感的方法;首次提出了一种新颖的光纤光栅温度补偿型应变检测方法和振动传感方法;更多还原

【Abstract】 Today, our society has gone into an age of information. Being another information carrier, photon is playing an important role gradually. Optical fiber has been widely used as the most important transmission medium in the telecommunication networks. Various optical fiber devices and systems have been developed, which greatly enhance the flexibility of the network. Fiber gratings are being considered as a landmark and attracting considerable interests in applications, 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 such detection fields as stress﹑temperature﹑pressure﹑electric current﹑voltage﹑vibration and so on. 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 dissertation, we mainly focus on the research and realization of fiber Bragg grating networks, including the principles and experiments of sensing and demodulation techniques. The main contents are listed as follows:1.Generally introduce the present situation and development of fiber sensing technique and fiber grating sensing technique. The fundamental theory of fiber grating and its fabrication method are also analyzed. The basic principle of fiber Bragg grating sensor and demodulation and multiplex technique can be found in this dissertation.2. The characteristics of FBG have been studied by means of the coupled-mode theory. Reflectivity﹑center wavelength and 3dB bandwidth of several types of fiber grating, such as uniform period FBG, long period fiber grating have been deduced. Moreover, the network principle about fiber sensor and fiber grating sensor has been described, in which the limitation of sensing pots in a network has also been given.3.In order to make clear of the key points of FBG sensing technique, the method of更多还原