【作者】 张超俐；

【导师】 陈林；

【作者基本信息】 湖南大学 ， 信息与通信工程， 2010， 硕士

【摘要】 全光交换技术是未来通信网最具潜力的新一代交换技术,能够提供高速、大容量的传输及处理能力,打破信息传输的“瓶颈”,可以在很长的时间内适应高速宽带业务的带宽需求。针对目前的交换技术状况与器件发展水平,结合当前电子器件处理技术的优势,人们提出了一种光电混合的光分组交换—光标记交换技术,它是实现全光网络最有效的方法。本文基于这样一种研究背景,在光标记和光分组的产生、交换、传输等相关技术方面,进行了一些理论分析、模拟仿真和实验研究,主要研究内容如下：一、提出并实验研究了一种以正交频分复用(OFDM)信号作为标记的光分组传输新方案。正交频分复用技术可以抵抗光通信中的色散效应,将OFDM引入光标记交换系统,具有抗色散、抗干扰、频谱效率高等多方面的优势,能够实现信号的长距离传输。实验中,将10Gb/sOOK载荷和2.5Gb/sOFDM标记分别通过强度调制器调制在不同波长的光载波上,再用光耦合器耦合产生光分组。经过40km单模光纤传输后,在接收节点用光交错复用器将载荷与标记分离,分别用相应的接收机进行检测。实验结果表明光分组信号经光纤传输后,仍能很好的恢复载荷信号和标记信号,功率损耗小,适于长远距离传输。该方案简单易行,标记与载荷分开调制,不受消光比限制,串扰不明显,容易实现标记和载荷的合并与分离。二、提出并仿真研究了一种正交频分复用(OFDM)信号和相移键控(PSK)信号相结合的新型正交调制光标记方案。用强度调制产生2.5Gb/sOFDM标记信号,用相位调制产生10Gb/s载荷信号,在同一个光载波上实现OFDM标记与PSK载荷的正交调制,产生光分组信号,通过单模光纤进行传输,并在接收节点采用各自的检测方式进行接收。OFDM信号能帮助克服色散的影响,而PSK信号强度恒定,可以有效抑制非线性效应。因此这种正交调制光标记方案,将能进一步实现信号的高效传输。理论分析和模拟仿真都证明了该方案的可行性。该方案具有配置简单、频谱效率高、适合长距离传输等特点。更多还原

【Abstract】 All-optical switching is the most promising switching technology for the future communication networks. It can provide the ability for transmission and processing of high speed and large capacity to break the "bottleneck" of information transfer. So it will adapt to bandwidth requirements for high-speed broadband services in a long time. In view of current development level of technologies and devices, combining the advantages of processing technologies of electronic devices, an optical packet switching technology based on the electronic and optical system has been proposed—optical label switching, which is the most effective way to achieve all-optical network. In this paper, based on such a research background, generation, swapping and transmission of optical labels and optical packets are researched by theoretical analysis, numerical simulation, and experimental verification, mainly including:Firstly, a novel optical packet transmission scheme, in which an optical orthogonal frequency division multiplexing (OOFDM) signal has been generated as a label, has been proposed and experimentally demonstrated. Orthogonal frequency division multiplexing (OFDM) can combat dispersion in optical communication. Using OFDM in optical label switching system, there will be so many advantages such as anti-dispersion, anti-interference and high spectral efficiency that can realize long-distance signal transmission. In the experiment, 10Gb/s OOK payloads and 2.5Gb/s OFDM labels are modulated on two optial carriers of different wavelengths by intensity modulations, respectively. And then optical packet were generated by coupling optical payloads and optical labels. After 40km single-mode fiber transmission, payloads and labels are separated by an interleaver, and then detected by the corresponding receiver. The experimental results show that payload signals and label signals can still be well restored after 40km fiber transmission of optical packet. Power losses are so little that the scheme is suitable for long-distance transmission. The scheme is simple and has the following advantages:payloads and labels are modulated separately, so there are no restrictions of the extinction ratio and crosstalks are not obvious. It is easy to realize combination and separation of payloads and labels.Secondly, a novel orthogonal optical labeling scheme based on orthogonal frequency division multiplexing (OFDM) singals and phase-shift keying (PSK) signals has been proposed and simulation demonstrated.2.5Gb/s OFDM label signals are generated by intensity modulation and 10Gb/s payload signals are generated by phase modulation. OFDM/PSK orthogonal modulation on the identical optical carrier is achieved and optical packet is produced. After single-mode fiber transmission, payloads and labels are received with the respective detection mode. OFDM signals can help to overcome the dispersion effect and PSK signals can suppress the non-linear effect effectively because of the constant intensity of PSK signals. Therefore, this orthogonal optical labeling scheme, will further realize efficient signal transmission. The feasibility of this scheme is proved by simulation and theoretical analysis. This scheme is characteristic of simple structure, high spectral efficiency and suitable for long-distance transmission.更多还原