【作者】 李本泰；

【导师】 李康；

【作者基本信息】 山东大学 ， 无线电物理， 2010， 硕士

【摘要】 从上世纪光纤和优良激光器的诞生,到近些年来海底光缆和普通光纤作为信息主干道的广泛应用,人类逐步跨入了光纤通信时代。光纤以其通信容量大、可靠性高、传输损耗小等优点为当前的信息时代所接受。一方面,光纤通信技术迎合了人们对大容量信息传输的需求；另一方面,人们在追求信息化所带来的便利的同时,也进一步推动了光纤通信技术的进一步发展。然而,在追求传输容量的同时,人们正逐渐地更看重传输质量。当前,光纤通信系统的传输状况不甚乐观。除光器件本身发生故障外,光缆线路因为施工挖掘、鼠害、火灾和射击等因素而时常中断也是引发的光路中断的重要原因。为了解决光通信中光路中断的问题,本文主要探讨了光路保护系统的方案和组成。光路保护方案通过提供备用光路或者查询其它可用链路提供冗余保护。及时选通未损光路可避免不必要的损失,而其关键点在于切换凭据的可靠性,即：在线监测光缆线路所得到的光功率值的准确度与灵敏度。当前应用较多的方案在检测光功率值方面存在许多弊端,如准确度不高、不够灵敏、检测范围过小,且一旦设定切换阈值后就无法更改等等。针对以上弊端,本文在“1+1”光路保护方案的基础上,采用对数放大器、微处理芯片和光器件,设计和开发出一套大范围、高精度的光路自动保护系统。而且增加了网络通信模块,通过向微处理器移植uIP协议,实现了远程微机终端与在线控制模块的通信。此外,为了提高光功率值的准确性,本文对测试结果进行了分析并根据结果对系统进行了拟合和修正。经过实际运行与测试,本文所设计系统的光功率检测范围在-60～4dBm,光路切换时间在ms量级。较之与终端远程通信后做出响应的时间,系统自动切换的响应时间更短,满足ITU-T对于光缆保护线路的切换要求。本文提出了一种光纤线路自动保护方案,并进行了设计和实现。结果表明,该系统运行稳定、可靠,灵敏度和测量范围等各项工作指标均优于当前所应用的方案,对于提高光通信网络的可靠性具有重要意义。更多还原

【Abstract】 From last century when fiber and laser with excellent performance were invented to the recent years when submarine optical fiber cable and ordinary fiber are being used as the main channel of information transmission widely, the human has entered the era of optical fiber communications. Optical fiber is accepted by our information society mainly because of its larger transmission capacity, higher reliability and lower transmission loss. On one side, the optical fiber communication technique meets our human’s requirement for information with large capacity. On the other side, the optical fiber communication technique is also propelled by our human’s needs. However, we have transferred our attention to the quality of optical fiber instead of only staring at the capacity. Now, the transmission situation is not ideal for optical fiber communication system. Beside the damage of optical devices, the optical fiber communication is always cut down by optical fiber’s break caused by earthwork, rodents, fire, shooting and so on.This thesis mainly discusses the principles and compositions of the fiber protection system, just to overcome the problems caused by optical fiber’s break. The fiber protection system provides redundancy protection by providing backup lines or searching available lines. Unnecessary losses could be avoided if backup lines be selected in time. And the key point is to get a reliable switching standard which concerns about the accuracy and sensitivity for the optical power from optical fiber cable. Right now, there are many disadvantages for fiber protection principles being used, just like low accuracy, less sensitivity, small detecting range, fixed threshold once set and so on.To solve these drawbacks above, this thesis designs and develops a new fiber automatic protection system with lager detecting range and higher accuracy using logarithmic amplifier, micro-processing chips and optical devices on the basis of’1+1’ fiber protection system. Additionally, network communication module is added to realize the communication between the remote computer and the on-line detecting module by transplanting uIP to micro-processing chips. What’s more, this paper analyses and fits the test data and then amends the system in order to improve the accuracy. After running and testing, the optical power of the system designed can reach a range of-60-4dBm, and the switching time is at the lever of many micro-seconds. Compared with working by communicating with remote computer, it needs less time to response with faults just working alone. And the switching time reaches ITU-T’s standards.An optical fiber automatic protection scheme is proposed in this thesis, and it was designed and realized. The results showed that the system ran stably and reliably, with better performance in sensitivity and larger measurement range than current schemes being used now. So the work is very important for improving the reliability of optical communication networks.更多还原