光分组交换中副载波标签和竞争解决技术的研究

【作者】 郑勉；

【导师】 邱昆；

【作者基本信息】 电子科技大学 ， 光学工程， 2005， 硕士

【摘要】 光纤通信技术的发展使得单根光纤的传输速率超过了十Tb/s,这就要求基于光电光转换的路由器需具有巨大的存储容量和高速的信号处理能力。在电子处理速率和光纤传输速率失配的情况下出现了制约光网络发展的电子瓶颈。光分组交换以其较小的交换粒度,高速的交换速度,对各种上层协议的支持成为解决光网络电子瓶颈的最理想方案。本文将对光分组交换中的副载波标签的处理技术和竞争解决技术进行研究。在副载波标签处理技术的研究中,首先在理论上分析了各种副载波标签光分组在MZI 外调制器上的产生方案,并提出了一种三分支波导结构的单边带副载波标签光分组产生方案。研究发现必须采用副载波标签和净荷分开产生的技术,否则都存在标签对净荷或净荷对标签的干扰。接着进行了采用FBG 分离副载波标签和光净荷的仿真实验,验证了使用光滤波器分离副载波标签和净荷的可行性。最后进行了基于波导结构的ChebyshevⅠ型、ChebyshevⅡ型、椭圆型和Butterworth 型ARMA 光学滤波器的设计和仿真实现。在竞争解决技术的研究中,首先对反馈FDL 结构的竞争解决方案进行了理论分析,推导出了在两个优先级下的系统丢包率和平均时延公式,并对系统丢包率、平均时延与负载、输入光纤端口数和FDLs 数目的关系进行了数值计算。结果表明:反馈FDL 结构在低负载时对丢包率的改善非常明显,对高负载的改善却十分有限。并且随着FDL 数目的增加,对系统丢包率的改善不会趋于一个极限值,这是与采用波长转换器进行竞争解决方案的不同之处。反馈FDL结构的交换系统的平均时延随着负载的增大而增大;在低负载时,随着输入光纤数的增加而增大,而基本不随FDLs 数的变化而变化;在高负载时,随着输入光纤数的增加而减小,而随着FDLs 数的增加而增大。其次对SPC、SPL 和SPN 三种共享波长转换器结构的竞争解决方案进行了理论分析和数值计算,结果表明:SPC 结构的丢包率是SPL 和SPN 结构丢包率的极限。SPC 的丢包率随着波长数的增加而下降,但低负载下降的幅度要更多还原

【Abstract】 With the development of optical fiber communication, the data rate of transmission has exceeded 10Tb/s on a single fiber. It forces the traditional optical-electrical-optical router to have huge capacity of RAM and high-speed signal processing ability. When the electronic processing speed can not match the data rate of transmission in fiber, the electronic bottleneck appears that restricts the further development of optical network. Optical packet switching becomes a best solution of conquering electronic bottleneck owing to smaller switching granularity, higher switching speed and the support to the upper protocol. In this paper, the technique of subcarrier label processing and contention resolution in optical packet switching will be studied. In the part of subcarrier label processing, several kinds of the schemes that the optical packets with subcarrier label are generated on Mach-Zehnder Interferometer modulators, are analyzed in theory. A novel scheme of optical packet generation based on three branch-waveguides is proposed that realizes single sideband modulation of subcarrier label. All of the schemes except that the payload and subcarrier label are generated separately, present the modulation of payload to subcarrier label or subcarrier label to payload. A simulation is performed that the payload and subcarrier label are separated by fiber bragg grating. The success of the simulation verifies the method of separating the payload and subcarrier label by using an optical filter. A kind of ARMA optical filter based on waveguide structure is studied. Some optical filter models, such as Chebyshev, ellipse and Butterworth, are designed and simulated. In the part of contention resolution, the scheme based on feedback fiber delay lines is analyzed in theory. The formulations of packet loss probability and average delay time in this scheme are deduced. The results indicate that packet loss probability is reduced in low traffic load more rapidly than in high traffic load with更多还原