基于扩展Benes结构的光交叉连接节点中串扰积累特性分析

无论是光路交换还是光突发交换,都离不开有光开关矩阵组成的光交叉连接节点(OXC).OXC节点是组建波分复用光网络的基本单元,OXC节点引入的串扰成为限制其投入实用的主要原因.理论分析了基于扩展Benes(DB)结构和改进扩展Benes(GMDB)结构的三种典型OXC结构中的带内串扰,结果表明基于DB结构和GMDB结构的OXC节点可以完全消除低于二阶的各类串扰.数值模拟了基于两种结构的OXC节点中带内串扰的积累特性,发现基于GMDB结构的OXC节点能大大降低串扰引起的功率代价,实验测量了8×8DB结构和GMDB结构中串扰的影响,实验结果证实了GMDB结构的低串扰特点.同时与基于DB结构的OXC节点相比,基于GMDB结构的OXC节点对光开关串扰系数的要求放宽了5 dB,大大降低了对光开关隔离度的要求.     

多波长光交叉连接节点中的串扰研究

密集波分复用技术(DWDM)在提供传输能力的同时,还具有无可比拟的联网优势.光交叉连接(OXC)是其中的关键技术.由于OXC可对光波长进行全光的交叉连接,极大的提高了系统的容量.但由于在光链路上没有电的再生,使得噪音在光信道上积累起来,尤其是引入无法消除的同频串扰对系统造成了严重的影响.本文从全光通信网络(AON)的几种节点结构出发,讨论了信道的串扰机制,并对如何优化OXC节点结构进行了研究.     

光交叉连接结构的分类和推演

光交叉连接(OXC)是波分复用(WDM)全光网的核心节点技术,其结构直接决定了其性能,严格无阻塞是最根本的要求.对于已经提出的多种多样的OXC结构,本文归纳出四种最基本的无阻塞结构,在此基础上具体推演分析其它OXC结构,这样便清晰地论证了OXC结构的阻塞性.对部分阻塞结构提出了消除阻塞的修正方法.     

一种新型结构光交叉连接节点及其联网性能分析

通过对常见光交叉连接器(OXC)的改进,提出了一种具有有限波长转换能力的内部光交叉连接节点(L-WIXC),既具备冲突消解能力又降低成本.采用算法编程方法,分析比较了L-WIXC和其他两种现有OXC结构,以及基于不同信令协议的L-WIXC的拥塞性能,结果表明L-WIXC具有较低的拥塞概率,并且基于JET协议的L-WIX...     

信息流的特性及其对光交叉连接的设计考虑

本文详细分析了在主干网上传送的信息流及其流经交换节点时的特点,包括速率、波长的变换和匹配、信包的分拆和组装、上下路关系等。在设计用于主干传送网的光交叉连接时,必须密切结合这些特点,才能设计出相应的光交叉连接节点(OXC)设备,从而使得信息流能以更低的成本和更灵活的方式在网上传送。最后,我们设计了一种分级光交叉连接设备(OXC),分别结合了空分、波分和时分的特点。从节点吞吐量、成本和灵活性等方面来看,这种分级光交叉连接设备十分适用于未来大容量主干网络的建设。     

WDM网中同频串扰的研究

串扰是波分复用(WDM)光网络中限制光交叉连接(OXC)节点容量的一个重要因素.本文分析了相干和非相干串扰对通过OXC节点的光信号的影响,给出了固定和最佳判决门限两种情况下的光功率恶化,并进行了仿真计算.结果表明相干串扰对系统的影响很大.与固定判决相比,采用最佳判决可以降低串扰影响.串扰引起的光功率恶化主要取决于复用波数M,而与输入光纤数N关系不大.为了减小串扰对网络的限制,可以在OXC节点内使用滤波器.     

级联光交叉连接和光分插复用系统串扰研究

分析了光网络节点串扰产生的原因以及级联光交叉连接(OXC)和光分插复用(OADM)系统的串扰,对级联系统进行模拟,计算并分析了光开关隔离度、上路信号的功率差对系统误码率的影响,得出了光开关隔离度是产生串扰的主要原因、在光开关前进行功率均衡有利于提高系统误码性能等结论.     

光波导开关的最新进展

随着光纤通信技术的不断发展，作为光分插复用（OADM）和光交叉互联（OXC）核心器件的光开关作用日益突出。文章从开关单元结构、材料及调制机理三个角度对波导开关进行了划分，阐述了波导开关的基本原理以及当前的研究进展，对面临的一些技术挑战进行了分析，并提出了自己的观点。     

一种新型光交叉连接器的设计

由于光交叉连接器(OXC)在密集波分复用(DWDM)网络中起关键作用，文中提出一种采用双向环行器的新型光交叉连接器设计方案。其基本结构由一个双向环行器与一个光纤布拉格光栅(FBG)组成，构成一个2×2光交叉连接器，再根据这一基本结构设计出可满足实际需要的N×N光交叉连接器。此方法具有结构简单、体积小、价格便宜及所需环行器数量少(比传统的少67％) 等优点。最后，把新型光交叉连接器的插入损耗与传统结构连接器的插入损耗进行了比较。仿真结果表明，新结构比传统结构具有更小的插入损耗。     

INFORMA基于TMN 的OXC’s 信息建模

本文介绍了对多波长光传送网实施基于TMN管理中涉及的信息建模的方法问题,在建议了一组用于描述光传送网通用功能的基本传送对象类的基础上,讨论了几种典型OXC′s信息建模的方法,包括可能用到的对象类,这些方法和对象类为建立实际的、完整的OXC′s信息模型提供了的基础.     

串扰对密集波分复用网络扩展性的影响

串扰是限制密集波分复用网络扩展的一个重要因素。理论分析了三种典型光交叉连接中的串扰。结果表明基于扩展贝奈斯光交换结构的光交叉连接可以完全消除低于二阶的各类串扰,同时,若将可调谐的窄带滤波器引入到结构2中可以消除低于三阶的各类串扰。用数值模拟的方法分析了带内串扰对强度调制直接检测网络扩展性的影响。结果表明,基于扩展贝奈斯光交换结构的光交叉连接对器件串扰系数的要求得到了很大的放宽,用它来组建的密集波分复用网络具有很好的扩展性。串扰多是由构成光交换节点中各种器件的非理想性造成的,通过分析得出器件中产生的串扰可以从系统中得到很好的解决。     

Dynamic waveband grooming based on hierarchical integrated grooming auxiliary graph in multi-domain mesh optical networks

With the number of wavelengths in fibers increasing, the number of optical switching ports in conventional Optical Cross-Connect (OXC) keeps enhancing, so that waveband grooming technique is proposed to save the switching ports in OXC. Most of previous works focused on waveband grooming in single-domain optical network. Since the current optical backbone is actually divided to multiple domains according to the different network providers, it is necessary to study the waveband grooming in multi-domain optical networks. However, waveband grooming in multi-domain optical networks is more challenging than that in single domain networks because of the routing scalability and security issues. Therefore, in this paper, we propose a new heuristic Hierarchical Multi-domain Waveband Grooming (HMWG) algorithm based on Hierarchical Integrated Grooming Auxiliary Graph (H-IGAG) to reduce the total number of optical switching ports. The H-IGAG is compared of the Intra-domain Waveband Integrated Auxiliary Graph (Intra-WIAG) and the Inter-domain waveband Virtual Topology Graph (Inter-VTG). For the demand in single-domain, HMWG directly computes the route from the source node to destination node in the single-domain with waveband grooming on Intra-WIAG. For the demand spanning different domains, HMWG first computes the route from the source node to the selected border node in source domain and computes the route from the selected border node to the destination node in destination domain with waveband grooming on Intra-WIAG, respectively. Then, HMWG computes the route from the selected border node in source domain to the selected border node in destination domain with waveband grooming on Inter-VTG. Simulation results show that, compared with previous grooming algorithm, HMWG can obtain better performance.     

A scheme of optical interconnection for super high speed parallel computer

An optical cross connection network which adopts coarse wavelength division multiplexing (CWDM) and data packet is introduced. It can be used to realize communication between multi-CPU and multi-MEM in parallel computing system. It provides an effective way to upgrade the capability of parallel computer by combining optical wavelength division multiplexing (WDM) and data packet switching technology. CWDM used in network construction, optical cross connection (OXC) based on optical switch arrays, and data packet format used in network construction were analyzed. We have also done the optimizing analysis of the number of optical switches needed in different scales of network in this paper. The architecture of the optical interconnection for 8 wavelength channels and 128 bits parallel transmission has been researched. Finally, a parallel transmission system with 4 nodes, 8 channels per node, has been designed.     

Performance analysis of metro WDM network based on an optical cross connects and arrayed waveguide grating demultiplexer

In this paper, we have demonstrated the quality-of-service offered by the metropolitan area network which is based on optical cross connect (OXC) and arrayed waveguide grating (AWG) demultiplexer operating at 10 Gb/s with 0.1 nm channel spacing for NRZ signal transmission. The data is successfully transmitted to a distance of 40 km with a reasonably good BER of 2.388 × 10⁻³⁵. The OXC and AWG demultiplexers in the proposed architecture allow incremental expansion in terms of the number of wavelength channels to be transmitted. Dispersion and crosstalk are the main signal-degrading factors arising from the operation of the OXC and the effectiveness of each factor is individually investigated.     

Migration of broadcast-and-select optical crossconnects from semi-static to dynamic reconfiguration and their physical layer modeling

Optical Crossconnects (OXC) are indispensable for the proliferation of broadband services. Next generation OXCs should be dynamically reconfigurable, to render the optical layer flexible and agile, cost competitive, in order to be a viable alternative to fully electronic solutions and multi-service, i.e. to be able to handle both optical circuits and packets equally well. In this work, an evolutionary migration scenario from semi-static to dynamically reconfigurable broadcast-and-select OXCs is presented. The cornerstone of this approach is modularity in both the node architecture and the corresponding functionality, since these two are inextricably linked. Here, the three evolutionary steps of a modular broadcast-and-select architecture are presented, their principle of operation is explained and their complexity is analyzed. The key building-blocks to implement these OXCs are optical switching elements operating in a gated mode and tunable wavelength converters. Concerning the physical performance of these architectures, an important consideration is that node capacity is traded for higher node cascadeability. This trade-off is studied extensively considering a combination of different switching technologies and optical components. Moreover, the 2R regenerative properties of the all-optical and optoelectronic wavelength converters play a key role in the node cascadeability assessment which is otherwise compromised by OSNR limitations. For this reason, analytical models providing an insight on how certain physical mechanisms are leading to performance degradation are used. The final assessment is made using a commercial simulation tool, allowing the derivation of conclusions for the size of the transparent islands.