【作者】 郭阳；

【导师】 童峥嵘；

【作者基本信息】 天津理工大学 ， 通信与信息系统， 2012， 硕士

【摘要】 光纤通信具有频带范围宽，传输损耗低和失真小等优点，在当今通信领域的发展过程中，正呈现一派欣欣向荣的发展景象。而光纤光栅的出现，则为这一发展注入了新的生机和活力。光纤光栅具有插入损耗低、成本低、稳定性好、耐腐蚀、不易受电磁干扰、便于复用、能在较恶劣环境中工作等优点，大大扩展了其应用范围，使光纤通信朝着集成化、全光纤化、智能化的方向加速发展，受到了人们的重视和青睐。干涉型光纤传感器与其他传感器相比，具有极高的灵敏度和分辨率，以及很大的动态响应范围，长期处于特定工作环境下的光学稳定性较好，在温度、液位、折射率、应变、湿度传感和水听器等领域中有广泛的应用。光纤光栅的双参量同时测量能够提供更多的信息和便利，有效推进了光纤光栅的实用化进程。本文采用将干涉型光纤传感器与光纤光栅相级联的方式，并利用干涉谱和光栅透射峰的不同响应灵敏度，实现了对双参量的同时测量，主要内容包括：1）简要介绍了光纤光栅近年来的发展以及特点和应用，分析了光纤传感器的传感原理及干涉型光纤传感器的研究现状，并对光纤光栅的双参量同时测量问题进行了现状分析和解决方法的研究。介绍了干涉型光纤传感器的基本理论，并列举了几种典型的干涉型光纤传感器，分析了各自的特点。2）介绍了光纤Bragg光栅（FBG）的温度和应变传感原理，然后对single-mode-multimode-single-mode（SMS）结构的干涉模式进行了详细分析，并利用光束传播法（beam propagation method，BPM）对干涉光场分布进行了数值模拟。提出了一种基于SMS结构与FBG级联的温度和折射率同时测量传感器。在SMS结构中，众多高阶导模在MMF中发生干涉，通过干涉条纹的漂移来感知外界参量的变化。实验测得SMS的干涉谱和FBG的透射峰对温度和折射率有不同的响应灵敏度，温度和折射率的测量精度分别为±0.22℃和±0.0015。3）分析了长周期光纤光栅（LPG）的温度和轴向应变传感特性，然后对保偏光纤（PMF）的双折射特性进行了研究，并设计了一种基于Lyot滤波器（Lyot fiber filter, LFF）和LPG的温度和应变同时测量传感器，其中LFF由在起偏器（PL1）和检偏器（PL2）中嵌入一段PMF构成，具有线性结构，干涉谱的稳定性较高，实验测得其干涉谱和LPG的透射峰对温度和应变有不同的响应灵敏度，温度和应变的测量精度分别为±1℃和±25με。4）分析了MMF-SMF-MMF（MSM）结构的干涉原理，并用BPM法对干涉光场分布进行了数值模拟，设计了一种基于MSM结构和FBG的温度和折射率同时测量传感器，利用敏感矩阵实现了双参量的同时测量，温度和折射率的测量精度分别为±0.32℃和±0.0023。由于MSM结构中SMF的包层模容易受到外界环境的影响，故具有较高的灵敏度，实验测得MSM结构的温度灵敏度是FBG的5倍。更多还原

【Abstract】 Optical communication is appearing a booming prospect due to the advantages of broadfrequency band, low transmission loss and small distortion. The optical gratings inject newvitality and vigor to the optical communication development with many instinctiveadvantages, such as low cost, high stability, corrosion resisting, immune to electromagneticinterference, multiplexing capability, adapt to work under hostile environment, and so on.Optical communication is developing toward the aim of integration, all-fiber devices, andintelligence, which is valued and favored by people.Compared with the conventional sensors, the fiber-interference-based sensor has broadresponse range, much higher sensitivity and resolution, and is also stable under specialworking environment, which has been applied in many sensing areas, such as temperature,strain, liquid level, refractive index, humidity and hydrophone.Simultaneous measurement of dual parameters can offer more information and greateravailability, which promote the practical process of fiber gratings. This thesis mainly focuseson the simultaneous measurement of dual parameters by using the combination of a fibergrating and a fiber-interference-based sensor. The main content includes:1) Depict generally on the development and applications of fiber gratings in recent years, andintroduce the simultaneous measurement of dual parameters of the fiber gratings. Analyzethe sensing principle and research status of fiber-interference-based sensors, and list sometypical fiber-interference-based sensors.2) Introduce briefly the temperature and strain sensing principle of fiber Bragg grating(FBG),and analyze the interference modes of single-mode-multimode-single-mode(SMS)structure in detail, then the numerical simulation of optical field distribution is carried outby use of beam propagation method(BPM). A sensor for simultaneous measurement oftemperature and refractive index(RI) is presented. The excited high order guided modesinterfere in the MMF. Due to the different response sensitivity coefficients of SMS andFBG, the simultaneous measurement is achieved with the resolution of±0.22℃和±0.0015, respectively.3) The temperature and axial strain sensing principle of long period grating(LPG) and thebirefrigent effect of polarization maintaining fiber(PMF) are studied. A sensor forsimultaneous measurement of temperature and strain is designed by cascading an LPGand a Lyot fiber filter(LFF), which has a linear configuration with stable interferencespectrum. By measuring the different wavelength shifts of LFF and LPG, thesimultaneous measurement is achieved by use of a well-conditioned sensitivity matrixequation, and a resolution of±1℃和±25με is obtained.4) A sensor for simultaneous measurement of temperature and RI is proposed by using a combination of an MMF-SMF-MMF(MSM) structure and an FBG. Firstly the interferenceprinciple of MSM structure is investigated. Considering the cladding mode nature of theSMF is more vulnerable to other parameters, the temperature sensitivity coefficient ofMSM structure is five times higher than that of FBG. Meanwhile, the numericalsimulation of optical field distribution is carried out by means of BPM, and thesimultaneous measurement is demonstrated due to the different responses of MSM andFBG. The resolution of±0.32℃and±0.0023is achieved.更多还原