【作者】 王杰；

【导师】 饶云江；

【作者基本信息】 电子科技大学 ， 光学工程， 2013， 硕士

【摘要】 同时利用光纤作为传感与传输介质的分布式光纤传感器(DOFS)与其他传感器相比，具有抗电磁干扰、大范围和长距离测量、抗腐蚀等优点，被广泛研究和报道。本文研究的相敏光时域反射仪(Φ-OTDR)与其他分布式光纤传感系统相比，具有响应速度快、灵敏度高、系统结构简单等优点。与传统的OTDR结构相似，不同的是通过注入高度相干的脉冲光，并探测光纤各部分的后向瑞利散射光在探测器处的干涉光。实验证明Φ-OTDR系统能探测更微弱的扰动，可以应用于油气输送管道、国境边线、军事基地等重要领域的安防监测。目前国内外对Φ-OTDR系统的研究主要集中在提高系统分辨率和延长传感距离。本文研究了基于EDFA和分布式光纤拉曼放大器混合放大的Φ-OTDR系统，利用双向拉曼泵浦对探测光进行拉曼放大，补偿了探测光的传输损耗，并均衡了探测光的功率分布，延长了系统的传感距离，实现了超长距离的Φ-OTDR系统。本课题主要从延长系统传感距离、开发系统软件、硬件仪器化和现场应用研究等几个方面开展了工作，完成了以下具体工作：(1)总结了分布式光纤传感技术及国内外研究现状，尤其是基于Φ-OTDR技术的分布式光纤传感系统，并基于Φ-OTDR的传感原理，理论分析了影响传感系统性能的关键因素，同时介绍了目前常用的光放大器及其技术原理；(2)搭建了一个基于EDFA放大和声光调制的Φ-OTDR分布式光纤传感系统，在20km的传感距离上获得了20m的空间分辨率；(3)对分布式光纤拉曼放大理论进行了数值仿真，并分别基于一阶和二阶光纤拉曼放大搭建了Φ-OTDR分布式光纤传感系统，实现了74km和84km的传感距离，为目前报道的Φ-OTDR分布式光纤传感系统最长传感距离；(4)基于VC++、MFC设计并开发了具有菜单视图结构的超长距离相敏光时域反射仪系统软件，并采用了MSSQL Server管理报警日志数据库；(5)完成系统硬件仪器化工作，使其成为一套可实用的工程样机，并基于该样机进行了室外现场应用研究，研究了传感光缆在挂揽、铺地、埋地安装方式下，系统对侵扰的检测效果。更多还原

【Abstract】 Comparing with other sensors, the distributed optical fiber sensor (DOFS), whichuses optical fiber as the sensing and transmission medium, has advantages ofresistance to electromagnetic interference, large-scale and long distance measurement,corrosion resistance, and etc. Thus it is widely researched and reported. In this paper,it is studied a kind of DOFS-the phase-sensitive optical time-domain reflectometer(Φ-OTDR) system with characteristics of quick response, high sensitivity, simplestructure, and so on. The Φ-OTDR has the structure similar to the conventionalOTDR, however, the difference is the injecting light pulse is strong coherent, and thepower of interference light detected is induced by backward Rayleigh scattering oflight from all parts of the optical fiber using the photonic detector. Thus the Φ-OTDRsystem has the ability to detect weak disturbances, and can be applied in securitymonitoring of important fields, such as oil and gas pipelines, the border line, militarybases and so on.The research on the Φ-OTDR is mainly concentrated on how to improve thespatial resolution and extend the sensing distance. In this paper, an amplifiedΦ-OTDR system is studied based on the hybrid EDFA and distributed optical fiberRaman amplifier. The transmission loss of detecting light can be compensated withRaman pump by making use of bi-directional pump structure which can balance theoptical power distribution along the fiber route. A longer distance Φ-OTDR sensingsystem is realized by this way.The following work is carried out, which includes from sensing distanceextending, system software developing, hardware development and the applicationtests. The details are listed as follows:(1) The distributed optical fiber sensing technology and research is summarized,especially that using Φ-OTDR technology. The key factors influencing theperformances of Φ-OTDR sensing system are analyzed theoretically. At the same time,different amplifying technologies commonly used and their technical principles areintroduced.(2) A distributed optical fiber sensing system using Φ-OTDR based on EDFAamplification and acousto-optic modulation is achieved, with spatial resolution of 20m and sensing distance of20km.(3) The gain of the distributed optical fiber Raman amplification is simulatednumerically. Based on the first-order and second-order optical fiber Ramanamplification, the Φ-OTDR system with sensing distance of74km and84km, areachieved respectively, which is the longest Φ-OTDR sensing system reported so far.(4) The system software of Φ-OTDR is developed with structure of menu/viewbased on VC++, MFC, and the alarm log is designed and its data base is managed byMSSQL Sever.(5) A prototype of Φ-OTDR is realized for practical uses. Fileds experimentsbased on this prototype is studied for validating the intrusion detection effect indifferent installation cases for the fiber cable.更多还原