【作者】 李国玉；

【导师】 袁树忠； 刘波；

【作者基本信息】 南开大学 ， 光学， 2007， 博士

【摘要】 本论文是在国家科技部863项目和天津市科技重大攻关项目的支持下完成的。光纤光栅是近几年发展最为迅速的光纤无源器件之一。光纤光栅作为传感元件,它具有其它传感器无可比拟的优点,即感应的信息用波长编码,而波长这个绝对参量不受光源功率的波动、连接或耦合损耗的影响。另外,光纤光栅传感还可以通过波分复用、空分复用和时分复用等各种复用技术构成传感网络,即在一根光纤中可以连续写入或串接多个光纤光栅构成光纤光栅传感阵列,这是光纤光栅传感器独有的技术,也是降低光纤光栅传感系统成本,实现多点、分布式传感的重要途径。因此,光纤光栅传感阵列的解调就成为一个热点问题。虽然光纤光栅传感利用波长这个绝对参量感应外部信息,但是当外部多个参量综合作用时,而且当光纤光栅传感器的数目增加时,光纤光栅分布传感的解调就成为一个瓶颈。因此光纤光栅传感解调技术引起了世界各国有关研究者的广泛关注和极大兴趣。随着光纤光栅传感阵列和光纤光栅传感网络的发展,光纤光栅传感器数目急剧增加,这就涉及到传感器数据实时读取和处理等问题,即数据融合问题。在光纤光栅传感网络中,不但产生的大量数据需要实时处理,还需要对数据进行筛选,归纳,总结特征,形成对态势的评估,最终形成判断、识别。因此光纤光栅传感网络的数据融合也成为一个研究热点。本论文以光纤光栅为研究对象,对其传感特性和解调技术进行探讨和研究,并着重分析了光纤光栅传感的解调特性。主要内容和创新点有:1.概括介绍了光纤光栅传感技术和解调技术的发展和现状。着重介绍了传统解调技术的原理和特点,并分析了传统光纤光栅传感解调技术的不足。2.详细讨论了作为光纤光栅传感解调系统的两大部分:相位光栅和图像传感器。首先分析了体相位光栅特性及其分波原理,其次对CCD和InGaAs图像传感器的探测原理、结构等特性进行了描述和比较。3.概括介绍了倾斜光栅的原理结构,写入方法,而且利用体电流方法对倾斜光栅的耦合进行了理论分析,接着对倾斜光栅的透射谱进行了分析。我们写制了倾斜光栅,进行了透射峰的分析,并且对倾斜光栅应力传感和温度传感的特性进行了实验研究。最后对倾斜光栅的分波原理进行了阐述,并对基于倾斜光栅的解调技术进行了研究。4.提出了利用倾斜光栅分波,利用InGaAs图像传感器探测光强的光纤光栅传感阵列的波长解调方法。5.利用InGaAs图像传感器,结合波分复用、时分复用等技术,通过后端软件平台实现多点传感检测和多参量传感检测,并搭建了基于体相位光栅和InGaAs图像传感器的光纤光栅传感解调系统。这套解调系统不但尺寸小,功耗低,而且具有较高的解调速度,重复性和可靠性极高,基本实现了光纤光栅传感解调的智能化,具有很好的应用前景。6.提出了基于BP网络的多传感器数据融合技术对光纤光栅传感阵列采集的信息进行数据处理,并对应力、温度光栅传感器探测数据进行了数据融合,通过模拟仿真,融合速度快,融合精度高。更多还原

【Abstract】 This work is financially supported by the National 863 High Technology Project, and National Science Foundation projects. Fiber gratings are one type of developing fast passive fiber devices in recent years. As sensing element, they encode the sensing information in a wavelength form, which are their distinguished advantages over other transducers. That not only make the sensing information does not depend on loss of the system or fluctuation of the source power but also decrease the cost of sensing system and realize multipoint and distributed sensing. So the fiber grating sensing array interrogation has been a hotspot. Although fiber grating sensors utilize the wavelength to sense the parameters such as strain, temperature, pressure and etc., the fiber grating sensing will be difficult when multi-parameters are applied to them and the fiber grating sensors increase in number. Therefore, lots of researchers are interested in fiber grating sensing interrogation techniques. With the development of the fiber grating sensing network, the number of fiber grating sensors increase quickly, so the real-time sensor data collecting and disposing are necessary, that is data fusion. In the fiber grating sensing network, lots of data are not only disposed in time, but also analyzed and summarized, finally the judgment and recognition are generated. So the research of data fusion of fiber grating sensing network is a hotspot.In this dissertation, we mainly focus on the research and realization of fiber Bragg grating (FBG) interrogation, including the principles and experiments of sensing and interrogation techniques. The details are described as follows:1. Generally introduce the sensing techniques, especially the present situation and development of fiber grating sensing technique and FBG sensing interrogation techniques. Especially introduce the theory and characters of the FBG sensing interrogation techniques, and analyze the advantage and disadvantage of the fiber grating sensing interrogation.2. Introduce the two parts of the FBG interrogation system in detail: phase grating and image sensor. First, describe the characters and the demultiplexing theory of the volume phase grating. Secondly, describe the theory and structure of the CCD, InGaAs image sensors, and compare some characters of them.3. Generally introduce the theory and the manufacturing method of the tilted grating, analyze the coupling of the tilted grating with the volume current method. and analyze the transmitting spectrum. We not only write the tilted grating and analyze its transmitting spectrum, but also make the research of the strain sensing and temperature sensing of the tilted grating. Then analyze the demultiplexing theory of the tilted grating and make a study on interrogation technique for FBG sensing based on the tilted grating.4. A novel fiber grating sensing interrogation system based on the titled grating and InGaAs image sensor is presented.5. With the combination of WDM/SDM techniques, the interrogation system for the fiber grating sensing based on the InGaAs image sensor and volume phase grating may realize the measurement of the multi-points and multi-parameters. The interrogation system not only has small size, high interrogation speed, but also has high repeatability and high reliability. So it shows a good prospect.6. The multi-sensor data fusion technique for fiber grating sensing array based on BP network is presented, and the data information collected from the fiber grating sensor array is proposed with the technique. Furthermore, we make the data fusion for the strain and temperature grating sensors at the same time, and the fusion results show that the data fusion based on BP network has not only high speed, but also high accuracy.更多还原