The application of spectral-amplitude-coding optical CDMA in passive optical networks

One code family suitable for passive optical network based on optical code division multiple access is present. Though spatial coding is used for capacity enlargement, the corresponding encoding/decoding devices require less fiber ribbons than that of the spatial/spectral systems proposed previously and the code cardinality is maintained. In addition, the multiple access interference is eliminated in the decoders of the proposed network and the phase-induced intensity noise arising during the photo-detecting process is suppressed further. Therefore, larger capacity can be accommodated in the network with simplified coding hardware.     

Interference elimination in optical CDMA passive optical network using multiple-weight codewords

A spectral-amplitude coding optical code-division multiple access network for multimedia transmissions is proposed. This scheme allows users with different service requirements to transmit data without interference theoretically, and the number of service classes is flexible and can be any integer theoretically if the required light sources and optical components are available. Because the corresponding encoder/decoder uses arrayed waveguide gratings of smaller physical sizes, the imperfect phenomenon such as crosstalk in the encoders is alleviated and the realization is more practical for the application of passive optical networks. When the bit error rate is smaller than 10⁻⁹, the effective number of active users in this scheme is larger than that of classical SAC schemes supporting no differentiated service.     

IP over WDM光网分层体系结构

介绍了传统的 IP over WDM光网实现方案 ,指出各种方案的优缺点。阐述了 IP directly overWDM光网的分层结构实现方案 ,分析了各层功能 ,详细讨论了光层和光适配层。在指出分层结构实现方案的利弊后 ,讨论了波长标记和多协议波长交换方案。     

IP交换中流分类的神经网络方法

本文对IP交换机中流的分类问题进行了探讨。首先对现有的X／Y分类器进行了分析,指出其不足之处,然后总结了进行流判断时应考虑的各种因素。之后提出了一种利用Hopfield神经网络进行流分类的方法,并对其参数的选取进行了讨论。仿真结果表明,神经网络分类器可根据网络中流的具体情况,自动调节分类阈值,保证IP交换机利用的VC数基本稳定。与常规X／Y分类器相比,神经网络分类器可利用更少的VC交换更多的数据包。     

波带交换中一种新型的多颗粒光交叉连接结构

随着波分复用(WDM)技术的迅速发展和广泛应用,光网络中交叉连接的规模不断增大,网络结构也越来越复杂.为了降低WDM网络中光域传输和交换的成本,人们提出了波带交换(WBS)技术,并对此进行了大量的研究.文章介绍了部分WBS和多颗粒光交叉连接(MG-OXC)的基本概念,并提出了一种新型的MG-OXC结构.     

Modeling and performance analysis of IP access interface in optical transmission networks with packet switching

The article analyzes the influence of the Internet Protocol (IP) access interface on the packet loss probability and delay times in the optical packet switched network. The network and node model have been proposed, and the structure of the IP access interface, including assembler and holder, have been included in the analysis. It has been shown that the increase of the maximum optical packet sizes, as well as use of the holding feature as contention resolution mechanism, decrease the packet loss probability, but introduce delays at the optical network access points. Modeling and analysis were based on the discrete event simulation assuming self-similar traffic sources. IP packet lengths were modeled using empirical data. This work has been conducted while the author was affiliated with the Telecommunication Laboratory, Swiss Federal Institute of Technology (EPFL-STI-ITOP-TCOM), Lausanne, Switzerland     

基于光滤波器的光时分复用光谱压缩技术实验

提出了解复用窗口匹配滤波器的概念,分析了利用光带通滤波器提高光时分复用(OTDM)频谱效率的光谱压缩技术。基于自制的40Gb/sOTDM复用器,采用电吸收调制器(EAM)及时钟提取模块组成的反馈环路解复用模块,以阵列波导光栅(AWG)作为电吸收采样窗口(EASW)的匹配滤波器对4×10Gbit/sOTDM信号进行光谱压缩,实现了无误码传输100km及传输后的解复用。实验结果表明,AWG的使用使得OTDM信号的频谱效率提高至4倍。     

阵列波导光栅的研究进展

综述了阵列波导光栅的研究进展,分析了其多功能和多应用的特性,展示了它在未来波分复用通信网中巨大的应用前景。     

Low‐Loss Compact Arrayed Waveguide Grating with Spot‐Size Converter Fabricated by a Shadow‐Mask Etching Technique

This paper describes a low‐loss, compact, 40‐channel arrayed waveguide grating (AWG) which utilizes a monolithically integrated spot‐size converter (SSC) for lowering the coupling loss between silica waveguides and standard single‐mode fibers. The SSC is a simple waveguide structure that is tapered in both the vertical and horizontal directions. The vertically tapered structure was realized using a shadow‐mask etching technique. By employing this technique, the fabricated, 40‐channel, 100 GHz‐spaced AWG with silica waveguides of 1.5% relative index‐contrast showed an insertion‐loss figure of 2.8 dB without degrading other optical performance.     

WDM智能光网络与IP业务

详细分析了 ＷＤＭ光网络的结构以及联网技术的演进过程，对如何压扁网络层次，实现ＩＰ直接ｏｖｅｒ ＷＤＭ，发挥 ＷＤＭ光传送网的巨大带宽优势进行了研究，提出 ＭＰＬＳ是当前解决 ＩＰ层与光层的融合以及跨层管理问题的关键技术。     

WDM-PON中基于AWG的新型OVPN研究

在波分复用无源光网络(WDM-PON)中,提出了一种基于阵列波导光栅(AWG)的新型光虚拟专用网(OVPN)。OVPN采用环形结构,在不同光网络单元(ONU)之间使用波长通道直接通信,不仅保证了ONU之间通信的安全性,而且提高了网络生存性。分别从光功率损耗和系统误码率(BER)进行了数值分析,结果表明,本文结构不仅增加了通信的安全性,而且仅使用4个波长就能实现16个ONU的相互联接,从而节省了波长资源,且具有很强的抗串扰能力。     

新型平输入/聚焦场阵列波导光栅波长路由器

基于像差理论设计了具有平聚焦场的阵列波导光栅(AWG),其输入部分与输出部分采用对称,成为同时具有平输入场和平聚焦场,可以省略输入和输出波导,使输入/输出星形耦合器可分别直接与光纤阵列连接,结构得到了简化。设计了频率间隔为200GHz的9×9通道平场AWG波长路由器,光场传输模拟结果显示,所有波长的输出信号均聚焦在与传输方向垂直的一条直线上,验证了平场设计的正确性。     

时隙光突发交换网络调度问题研究

光突发交换（OBS）是构造下一代全光网络的潜在技术之一,但存在网络参数设计困难和阻塞性能有限等问题。文章介绍了一种新型基于时隙的OBS网络体系,简要阐明了其各部分功能,并将其与常规OBS网络进行了对比。提出了网络节点中关键的时隙分配与调度问题,并给出相应的在线调度策略,仿真结果表明BF算法性能较优。     

IP over WDM网中的综合选路算法

研究了IP over WDM网中,当节点不具备波长变换能力并且配备有限光收发器对时,如何利用综合选路(IR)算法为到达业务请求建立标签交换路径(LSP)。提出一种新颖的辅助图模型(AGM)表示网络的当前状态,基于AGM提出一种动态IR算法-最小光收发器对法(MTA)。MTA总是选择占用光收发器对最少的通路来建立LSP,仿真结果表明：与已有算法相比,MTA可以降低全网的阻塞率,从而提高业务通过率,并且有利于减少业务连接所经光／电变换的次数。     

光突发交换网络中基于标记可抢占的调度算法

根据光突发交换(OBS)网络核心节点的结构和功能 特点,分析了OBS网络核心节点的数据信道 调度算法,提出了一种新的基于标记可抢占调度算法(LPSA),并讨论和分析了算法的实 现过程。本文算法根据到达核心节点的控制包所属业务等级的突发数据(OB)包占用的网络带 宽决定 数据信道调度的方法,实现了合理的使用数据信道和各业务类别间的业务区分,最终达到改 善OBS网络性能的目的。     

IP通信网的发展和应用

先介绍互联网规约 (IP)网的来源经历。接着 ,较详细地分别说明分组交换的明显特点 ,路由器的作用和 IP网的发展与应用。最后简述大规模 IP网的概况     

On blocking time in multi‐class optical burst switching nodes

Recently, there has been an increasing research interest being directed to optical burst switching (OBS) networks because of its mature electronic processing capability and high‐capacity optical transport capability. The blocking time for an OBS node, representing the time duration in which a certain channel is occupied by some class of bursts, plays an important role in characterizing the performance of an OBS network. In this paper, we analyze this important metric for an OBS node with a horizonal and a single channel theoretically and numerically. On the basis of that, the burst arrivals are assumed to follow the Poisson process and the burst lengths have a phase‐type distribution, we are able to formulate a working mechanism of an OBS node into a multilayer stochastic fluid model. Using a level crossing arguments method, we are able to obtain the Laplace–Stieltjes transforms of the blocking time, from which n ‐order moments and the probability density functions of the blocking time can be further derived. We provide a numerical example to illustrate the theoretical analyses, and we further discuss the effects of the offset time and the arrival density on the blocking time through this numerical example. Copyright © 2016 John Wiley & Sons, Ltd.     

Proposal for a novel and simple WDM NRZ-DPSK system

A novel and simple non-return-to-zero differential phase shift keying (NRZ-DPSK) wavelength division multiplexing (WDM) system, which can simultaneously demultiplex and demodulate multiple wavelengths, is proposed and investigated in this paper.The phase-to-intensity demodulation principle is based on detuned filtering, which is achieved by using a single commercial array waveguide grating (AWG) in our scheme.By properly choosing appropriate AWG channels at the transmitter, the AWG at the receiver can act as both the demultiplexer and the demodulator of the DPSK signals.Simulations at 10, 20, and 40 Gbit/s show good flexibility and performance for the proposed system.     

An efficient mechanism for dynamic multicast traffic grooming in overlay IP/MPLS over WDM networks

This paper proposes an efficient overlay multicast provisioning (OMP) mechanism for dynamic multicast traffic grooming in overlay IP/MPLS over WDM networks. To facilitate request provisioning, OMP jointly utilizes a data learning (DL) scheme on the IP/MPLS layer for logical link cost estimation, and a lightpath fragmentation (LPF) based method on the WDM layer for improving resource sharing in grooming process. Extensive simulations are carried out to evaluate the performance of OMP mechanism under different traffic loads, with either limited or unlimited port resources. Simulation results demonstrate that OMP significantly outperforms the existing methods. To evaluate the respective influences of the DL scheme and the LPF method on OMP performance, provisioning mechanisms only utilizing either the IP/MPLS layer DL scheme or the WDM layer LPF method are also devised. Comparison results show that both DL and LPF methods help improve OMP blocking performance, and contribution from the DL scheme is more significant when the fixed routing and first-fit wavelength assignment (RWA) strategy is adopted on the WDM layer. Effects of a few other factors, including definition of connection cost to be reported by the WDM layer to the IP/MPLS layer and WDM-layer routing method, on OMP performance are also evaluated.     

用MPLS技术实现IP over WDM

提出了一种全新的高速宽带组网技术－基于MPLS的IPoverWDM网络技术,并对其进行了深入研究。这个方案在光联网技术中综合了目前先进的MPLS流量工程控制技术,特别适合于由可重构的OADM和OXC组成的以数据业务为核心的互联网络系统,而且它为最终在IP路由器上直接提供WDM复用功能铺平了道路。