Passive Optical Network Based On φ-OTDR

Over the years, it's agreed that the PON access network is the future development direction. There are two reasons for this condition. First, it provides the bandwidth to meet present and future needs of a variety of broadband services, so it have a good performance in solving the problem of broadband access. Second, it cost low both in equipment operation and maintenance relatively. Distributed optic-fiber sensing (DOFS) system is a kind of distributed sensing system using optic-fiber as the sensing medium, and carries on real-time remote security monitoring of the target within it.A new scheme for passive optical access network (PON) was proposed, which can provide security service and self-locate physical faults. This system not only has the features of electromagnetic immunity, anti-eroding and sensitivity, but also takes advantages of hardly being revealed, precise alarm locating, easily data processing and so on. As a novel alarm monitoring system, such a distributed sensing system is anticipated to be used widely in safety monitoring of military bases, national boarders, nuclear facilities, electrical power generation stations, jails, et al.This thesis introduces a lot of innovational theoretical and experimental work about the PON fiber access network system with function of security service. Detailed work is listed below:(1) The principles and application of optical fiber communication access network systems are analyzed, and the existing methods of PON are investigated and compared. Two PON systems architecture of EPON and WDM-PON have been researched.(2) Aφ-OTDR sensing system based on EDFA is designed and constructed. Disturbed signal experiments of system are completed. Sensor network design has been optimized.(3) The characters of this system which can provide security service and self-locate physical faults have been researched. The scheme, network performance, feasibility, cost, compatibility and other issues which are related to the integration of two networks also have been analysed concretely.(4)φ-OTDR sensing network and EPON communications network are integrated together. By processing the returned signal properly, the system can locate the intrusion point within the distance range of 13km, and achieve the spatial resolution of 100m.(5) The data acquisition and analysis technology is described, and the testing software ofφ-OTDR is developed on the basis of personal computer with the tool of Visual C++.(6) A WDM-PON experimental system is designed and constructed. The performance of this system is tested.(7)φ-OTDR sensing network and WDM-PON communications network are integrated together. By processing the returned signal properly, the system can locate the intrusion point within the distance range of 11km, and achieve the spatial resolution of 100m.