最小代价最大节点度数的稀疏光疏导方法

疏导可以增加多播业务请求成功传输概率并提高光纤链路带宽利用率,但波分复用光网络中所有节点具有疏导能力则会增加网络造价和复杂度.本文研究了稀疏疏导网络中疏导节点选择策略,提出基于最小代价最大节点度数的疏导节点选择策略;根据疏导节点和非疏导节点功能差别,改进了稀疏疏导网络中多播请求的疏导传输方法.结合最小代价最大度数疏导节点选择策略和多播业务稀疏疏导传输方法,提出一种根据网络业务阻塞率限定值指标实现多播请求所需最少数目疏导节点的稀疏路由方法.仿真结果表明:在网络给定波长数和光收发器端口数目情况下,所提策略能够节约所需疏导节点数目并优化疏导节点位置,降低网络节点构造造价.     

分布式光网络中的波长和端口数目优化分析

研究了分布式Mesh光网络中动态业务疏导问题中的波长和端口优化问题,通过对分布式Mesh光网络中不同业务和网络拓扑情况下的网络结点波长和端口使用数目的仿真分析,得出网络中的合理波长和端口数目配置,为网络规划和设计提供依据.     

三阶多粒度光交叉连接的优化设计研究

在采用密集波分复用技术的骨干网中,通过建立动态多粒度业务模型对由大粒度（光纤和波带）和小粒度（波长）组成的三阶多粒度光交叉连接所构成的节点的网络特性（阻塞概率和带宽阻塞比）进行了研究和仿真分析,并由此对三阶多粒度节点的结构参数和网络中的系统参数进行了优化设计.从仿真结果可以看出,所提出来的优化设计方案能够显著的减少节点结构的复杂度并改善阻塞性能,从而减小了网络中设备的规模和成本.     

基于光子晶体光纤中多抽运四波混频效应的新型光层组播技术

光层组播是未来透明光子网络中一项重要的全光信号处理功能,提出并实验证实了一种基于色散平坦高非线性光子晶体光纤中多抽运四波混频效应的光层组播方法,将一束信号光与两束连续抽运光同时输入高非线性光子晶体光纤中,通过多抽运四波混频过程,产生四个携带该数据信息的闲频光,从而实现了单一信号的四信道光层组播功能,组播信道波长在35.2 nm范围可调谐,组播信道最大间距4.4 THz,最大转换效率-22 dB,最优Q因子为5.3,该方法的特点在于基于光纤中的四波混频效应工作,因而具有对调制格式和比特率透明的 关键词： 光层组播 多抽运四波混频 光子晶体光纤     

基于光纤四波混频效应的新型组播方法

组播是波长路由光通信网络中的一项重要功能.提出并实验实现了基于高非线性光纤四波混频效应的全光组播方法,将一束载有数据的输入信号光和一束抽运光一起入射到一段高非线性光纤中,通过两个简并四波混频过程产生了两个携带该数据信息的闲频光,从而实现了单一信号的两信道组播,同时抽运光也会受到数据信息的调制.该方法的优点在于组播的实现只需要单一的抽运光源,而不需要再提供其他输入光,结构简单,组播光信号功率均匀、波长可调,并且具有进一步增加组播信道的能力. 关键词： 组播 四波混频 高非线性光纤     

适用于多粒度光网络的共享保护算法及其分析

结合多粒度光网络自身特点提出了两种适用于多粒度光网络中的共享保护算法,它们分别基于波带粒度和基于波长粒度对光层连接提供保护.仿真结果显示,提出的算法性能优于以往的专用保护算法,通过对仿真结果的分析,得出了网络参量变化对各个算法的影响.     

波长转换受限条件下的最优组播波长分配算法

扩展了静态组播路由和波长分配问题,引入了范围受限的波长转换器,改进了优化目标,新的优化目标为整个组播连接使用的波长转换器数目最少,同时保证源节点到每个组播成员的路径上使用的波长转换器数目均小于指定值.利用动态规划,在两种连接建立策略下对问题进行了求解,所得解可用于衡量启发式组播波长分配算法的优劣.     

适用于多粒度光网络的共享保护算法及其分析

结合多粒度光网络自身特点提出了两种适用于多粒度光网络中的共享保护算法,它们分别基于波带粒度和基于波长粒度对光层连接提供保护.仿真结果显示,提出的算法性能优于以往的专用保护算法,通过对仿真结果的分析,得出了网络参量变化对各个算法的影响.     

波群模型和支持流量疏导的光交换结构

针对多粒度应用,开发了一种用于流量疏导的波群模型,并引入一种基于此模型的新型智能交换结构.该光交换结构提供了独特的区分粒度到相应隧道进行有效处理的方法.此外,还讨论了控制层粒度分离时采用的两个关键的动态算法模块.仿真结果显示这种特殊的通道分离方法有效提高了处理动态连接请求时每个光路径的平均信号通道质量和阻塞性能.     

基于光子晶体光纤中双抽运四波混频效应的非归零到归零码型转换实验研究

提出并实验证实了利用色散平坦高非线性光子晶体光纤中双抽运四波混频效应实现非归零 (NRZ)到归零(RZ)码型转换的新方案, 将一束NRZ信号光与两束同步时钟脉冲光同时注入光子晶体光纤, 通过双抽运四波混频效应产生两个闲频光, 经过光学滤波后即可完成单到双全光NRZ-RZ码型转换. 与基于常规单抽运四波混频效应的码型转换方式相比, 本设计方案由于采用了双抽运四波混频效应, 因此具有双路组播信号波长可彼此独立选取的优点. 分析了码型转换器的波长调谐性及对输入光功率波动的容忍性, 得到转换信号的最优消光比和Q 因子分别为15 dB和5.4. 研究结果表明, 本方案既具有对比特率和调制格式透明的优点, 又避免了使用单抽运四波混频效应进行码型转换时两路组播信号波长相互制约的弊端, 且实现了全光波长转换和波长组播功能. 关键词： 码型转换 四波混频 双抽运 光子晶体光纤     

A new multi-granularity traffic grooming routing algorithm in IP over WDM networks

In IP over WDM networks, since there is a large bandwidth gap between a wavelength capacity and the actual bandwidth required by each user, it is necessary to multiplex low-rate traffic streams (LRSs) into lightpaths by traffic grooming. However, with the number of wavelengths increases, a large number of all optical (OOO) transmitting ports are consumed. Meanwhile, the multi-hop grooming with incorporating full-wavelength conversion capacity in each node requires too many optical-electrical-optical (OEO) ports inevitably. To solve theses problems, waveband switching and intra-band wavelength conversion are proposed. By integrating traffic grooming and waveband switching, this paper devises a new multi-granularity traffic grooming mechanism with the function of intra-band wavelength conversion. Based on the proposed mechanism and integrated grooming policy (IGP), a new heuristic routing algorithm called multi-granularity traffic grooming based on integrated auxiliary graph (MGIAG) is also proposed since the traffic grooming problem is NP-hard. Simulation results show that, compared to traditional integrated grooming algorithm (IGA), MGIAG can save more ports and obtain lower blocking probability. Compared to traditional single-hop traffic grooming algorithm (SHA), lower blocking probability and more savings in transmitting ports can be achieved by multi-hop grooming in MGIAG and IGA although they consume more OEO ports.     

Performance analysis of dedicated protection and shared protection for waveband switching based on multi-granularity optical cross-connect

In order to save the switching ports and the cost of Multi-Granularity Optical Cross-Connect (MG-OXC), the waveband switching technique was proposed to groom multiple wavelength-level traffic to a few waveband tunnels to be switched by a few switching ports in MG-OXC. At the same time, protection for fibers is very important to ensure the service continuity since each wavelength carries a lot of traffic. Although existing works have addressed the waveband switching protection, most of them separately considered only the dedicated protection or shared protection in static demand scenario and did not deeply analyze and compare the dedicated protection and shared protection in dynamic demand scenario. Therefore, in this paper, we deeply study the consumptions of wavelengths in fibers and ports in MG-OXCs for Waveband Shared Protection (WSP) and Waveband Dedicated Protection (WDP) in dynamic demand scenario, and propose the port-cost calculation and update methods based on a new waveband layered auxiliary graph that is developed based on MG-OXC structure. In simulations, we compare WSP, WDP, traditional end-to-end waveband shared protection and traditional end-to-end waveband dedicated protection. Simulation results show that the shared protection has smaller port-cost, better wavelength utilization efficiency and lower blocking probability than the dedicated protection with the same waveband switching policy, and the sub-path waveband switching has bigger port-cost, better wavelength utilization efficiency and lower blocking probability than the end-to-end waveband switching with the same backup wavelength assignment policy.     

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 new green multicast grooming protection algorithm in WDM optical networks

Since optical network carries a lot of traffic, survivability is very important to ensure the service continuity against network failures. Recently, multicast services become more popular to meet the huge multimedia demand in network, so that multicast survivability in optical network has got more attention. However, multicast survivability may lead to more energy consumption due to more redundant backup resources allocated. Since greening network is particularly important with the energy crisis keeping growing, green multicast survivability in optical network is a challenging issue. This paper focuses on the green multicast grooming protection problem in optical network and designs two auxiliary graphs that includes a virtual topology graph and an integrated graph to address the survivable multicast grooming, routing and wavelength assignment. Based on the auxiliary graphs, this paper proposes an efficient heuristic called green multicast grooming algorithm based on spanning path dedicated protection (GMG-SPDP), in which the network reliability and the energy efficiency are jointly taken into account. Simulation results show that, compared to other algorithms, the proposed GMG-SPDP not only has lower blocking probability and higher bandwidth utilization ratio, but also saves more energy.     

提高空间目标温度测量精度的波段优选方法

为提高空间目标温度的测量精度而进行波段优选方法的探索。建立空间目标温度测量数学模型和波段优选评价函数数学模型,仿真分析探测波段对红外系统的测温灵敏度、温度分辨力和信噪比的影响,实现系统探测波段的优选。仿真结果表明,优选的探测波段为中心波长范围8.0 m～9.6 m,波段宽度60 nm,温度分辨力最高可达到0.06 K,同时可获得大于5的信噪比。结论:提出的方法可以使测温灵敏度和温度分辨力分别平均有8.7%和11.3%的提高。     

新颖的PPLN电光开关

在分析基于级联二阶非线性效应的准相位匹配周期极化铌酸锂(PPLN)波导全光波长变换器的有关参量容限的基础上,提出PPLN波长变换器的电光调控设想,并给予简要论证,论证结果是可行的,从而可实施电控调谐来自动补偿其失配,进而也可实现光开关的功能 关键词： 准相位匹配 周期极化铌酸锂 波长变换 光开关 电光效应调控     

An optical multicast packet switching architecture shared with limited-range multi-wavelength converter and full-range wavelength converters

Optical packet switch with multicast capability can inspire a broad range of multipoint to multipoint applications in future optical networks. An optical multicast packet switching architecture, equipped with feedback shared small number of limited-range multi-wavelength converters (LMWCs) and output shared some full-range wavelength converters (FRWCs), is proposed for a wavelength-division multiplexed optical multicast network to improve multicast performance in the paper. The FRWCs are used to overcome the performance degradation in terms of packet loss probability due to only use LMWCs. In the architecture, the two converters are shared by all the multicast packets importing to the optical multicast switch node. A maximum bipartite matching with minimum edges weights strategy was designed to employ fewer wavelength converters and avoid useless degradation of optical signal quality for the architecture to improve the node performance. The simulation results show that the proposed architecture and its wavelength converter scheduling algorithm can reduce the multicast packet loss probability with relatively lesser wavelength conversion cost.     

WDM网状网中动态域间流量疏导策略

对波分复用(Wavelength Division Multiplexing,WDM)网状网中的动态域间流量疏导问题进行了深入研究.在源路由模式下,提出了一种基于固定备选路由方式的动态域间流量疏导算法,并在其基础上提出了只考虑波长均衡和同时考虑波长均衡与业务均衡的改进方法.该算法可以有效地避免路由环,得到较低的阻塞率,节省全网的收发器数目和波长资源.仿真结果表明,这种算法可以有效地改善网络性能.