【作者】 吴薇；

【导师】 姜德生；

【作者基本信息】 武汉理工大学 ， 信息与通信工程， 2009， 博士

【摘要】 随着嵌入式技术、计算机技术和网络技术的不断发展,构建大型分布式光纤传感网络,使其具有更稳定的性能和更强大的功能,更适用于大型和复杂的结构监测,是未来的研究和发展方向。设计开发一种实时大容量光纤传感解调系统成为当前的迫切需要。在此背景之下,论文深入研究了光纤光栅传感原理与技术,设计并实现了新型大容量实时光纤光栅传感解调系统,并将其在大型装备健康监测的工业现场进行了应用测试。论文主要完成了以下工作：(1)在分析现有典型光纤传感解调方案的基础上,结合光纤光栅传感复用技术提出了一种新型的大容量光纤光栅传感解调方案。实验表明,采用可调谐窄带光源的新型大容量光纤传感解调方案与传统解调方案相比,具有较高的系统容量和信噪比。(2)分析比较了传感常用光源性能,详细研究了掺铒光纤放大器和半导体光放大器的基本理论,分别构建了采用掺铒光纤放大器的可调谐环形腔掺铒光纤激光器和基于半导体光放大器的可调谐环形腔频域锁膜激光器,并将激光器作为光纤传感解调系统中的光源。实验结果表明,将所构建的可调谐窄带光源用于所设计的大容量光纤传感解调系统作为光源,输出光功率相对于传统使用宽带光源的方法相比有显著增强,可提高系统信噪比(SNR),增大系统容量,有效改善系统性能。(3)研究了光纤F-P滤波器的工作原理、特性与技术指标,并采用实验方法对可调谐F-P滤波器进行研制。利用V型槽结构对准方法实现F-P滤波器,其所得光谱输出自由谱区可达近90nm,3dB带宽约0.32nm,插入损耗小于5dB。在压电陶瓷的驱动电压作用之下,法布里腔的腔长将随之相应变化,在变化的腔长作用下,透射波长也会发生相应变化,技术指标基本满足光纤传感系统要求。(4)对实时大容量光纤传感解调系统进行了研究与设计。采用了FPGA配合高速DSP芯片来代替传统的微控制器进行光栅信号的检测与计算。利用FPGA实现高速实时并行光纤光栅的信号检测,采用高速DSP芯片进行系统波长的运算。该系统具有高速的实时处理能力,并可提供丰富的接口类型,满足实时以太网通信的应用需要。由于采用可调谐窄带激光光源及高精度检测电路,该系统具有较高的运算速度和精度,将信号的高速运算和数据传输有机结合在一起,使得整个系统性能得到较大提高与完善。(5)将大容量光纤光栅传感解调系统在港口的煤炭装卸现场对煤炭装卸设备的健康监测中进行了应用测试。测试结果表明,大容量光纤光栅传感解调系统可在实际工程中的工业现场中安全可靠稳定地工作,可以很好地实时监测工业现场关键测试点的信号动态响应,且可以达到实验室所测得的系统各项性能指标。更多还原

【Abstract】 With the developments of the embedded technology and internet technology, we focus more attention on the building large-scale distributed fiber sensor network with more stable performance and powerful function because of the requirements of more extensive and complicated configuration monitor system. As the key technology of the network, the research of large scale real-time fiber sensor system is necessary. The principle and technology of fiber grating sensor are illustrated deeply in this article. And base on the study, a demodulation solution for large-scale, real-time fiber grating sensor with tunable narrow source, which has been tested in the healthy monitor system for some large scale equipment, has been designed. The contents below are discussed in this article:(1) After analyzing the typical fiber sensor demodulation solution, a new large scale fiber grating demodulation solution based on the fiber grating sensor multiplexing technology is designed. Higher system capacity and better SNR have been realized in the experiments compared with the traditional demodulation solution.(2) The performances of traditional sensor source are analyzed and compared. Based on the deep study of EDFA and SOA working theory, the tunable ring cavity laser with EDFA and the tunable ring cavity frequency domain mode locked laser with SOA are designed respectively and used as source for fiber sensor demodulation system. The experiment result showed greater output optical power compared with the traditional source. Besides, the SNR and the capacity of system are enhanced greatly. The total system performance is improved obviously.(3) Based on the principle, characteristic and specification of fiber F-P filter, the tunable FP filter is developed in the experiment. The output spectrum of F-P filter based on V-groove collimation has 90nm free bandwidth,0.32nm 3dB bandwidth and less than 5dB insertion loss. The F-P cavity length can be adjusted with piezoceramics drive voltage. And the passband wavelength is variable with variable cavity length corresponding. The all specification can meet the requirements of fiber sensor system.(4) The real-time large scale FBG sensor demodulation system is studied and designed. Novel FPGA and high speed DSP chip, instead of traditional MCU, are applied in detecting grating signal. FPGA is used to realize the real-time signal detection of parallel fiber grating in high speed, and the high speed DSP can complete the system wavelength computing. The system has the capacity of high speed and real time process and could provide enough interface types to meet the requirements of Ethernet application. Because the application of tunable narrow band laser source and high resolution detection technology, the system has higher compute speed and resolution. And the high speed process and data conservation are combined, which improve the system performance greatly.(5) The application test of fiber sensor demodulation system in healthy monitoring of coal handling equipment was carried out. The system can work safely and stably, and the test result show well real-time monitor performance on dynamic response of the key test point, which achieve the performance testing in laboratory.更多还原