WDM光网络中OXC结构对带内串扰积累的影响

串扰是波分复用(WDM)光网络中光交叉连接(OXC)投入实用的最大障碍。理论分析了基于扩展Benes(DB)结构和改进扩展Benes(GMDB)结构的3种典型OXC节点结构中的带内串扰,并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。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。发现基于GMDB结构的OXC节点能大大减少带内串扰的积累,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5dB,说明OXC节点结构的选择对消除串扰尤为重要。     

一种新型光开关交换器

探讨了光偏振现象和旋光现象的特点 ,进而利用偏振和旋光现象提出一种新型光开关交换器。这种交换器具有结构简单、与输入光的偏振态无关、不会产生相位差、插入损耗和信道串扰小、响应速度快、器件体积小等优点 ,同时可以使用此器件和光波分复用 /解复用器相结合 ,方便地实现任意波长的上下路。对 2× 2开关交换器的性能进行了分析 ,结果表明它的插入损耗和信道串话都很小。     

带间与带内串扰的理论分析与实验研究

在波分复用(WDM)系统中不同信道之间的串扰将恶化每路信号的消光比,而多波长光交叉连接网络中还会出现带内串扰的情况,它所产生的拍频噪声对系统的影响远大于带间串扰。从不同的角度分析了这两种串扰,理论分析的结果与实验现象吻合良好。     

3R光电波长变换器对WDM网中串扰的影响

具有光叉连接（ＯＸＣ）节点的波分复用（ＷＤＭ）光网络中,串扰是一个重要的限制因素。本文针对基于分送耦合开关的ＯＸＣ结构,分析了相干和非相干串扰引入的光功率恶化并进行了仿真计算。结果表明相干串扰是影响传输质量的重要因素,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。如果在ＯＸＣ节点内采用３Ｒ光电波长变换器（ＯＥＷＣ）,串扰对系统的影响会降低。     

光通信波分复用/分路器件

本文介绍了一种新型波分复用/分路器件,一个n面棱镜可实现n路或n-1路通道的复用/分路。其结构简单,并有利于反馈隔离,克服串扰。     

一种基于反射镜的2×2机械式光开关

鉴于低端口机械式光开关在未来光网络中的应用前景,研制出了一种基于反射镜的2×2机械式光开关。介绍了该器件的结构、原理及影响重复性的因素。该器件用于光交叉连接和光路信号上下载中,实验和测量结果表明具有插损低、可靠性好的特点,应用前景极其广泛。     

光网络中的OXC研究

本文介绍了光交叉连接(OXC)节点在光网络中所处的位置,分析了透明OXC节点和非透明OXC节点两种结构的构成方式.同时分析了OXC节点的串扰性能和利用GMPLS协议实现OXC节点的控制方式.     

多波长光交叉连接节点的优化设计

在WDM光网络中，光交叉连接（OXC）节点的串扰是限制网络规模的关键因素，提高光开关的隔离度是降低OXC串扰的一条途径，文章比较了3种不同结构的光开关矩阵的串扰特性，在此基础上对OXC节点进行了优化设计，改进后的OXC节点的串扰性能大的改善，网络规模也因此而得到了极大地扩展。     

阵列波导光栅在光纤通信网络中的应用

基于集成光学的N×N阵列波导光栅(AWG)是波分复用传输网络最成功的光滤波器之一,是光子网络的关键基础元件,它可用于光信号的复用、解复用、光路上/下分插复用、光交叉连接,波长路由等。 波长N×N复用/解复用器 N×NAWG具有波长间隔小、信道数多、串音较低、输出平坦等特点,是较为理想的波分复用全光器件。该复用器由N个输入/输出波导,两个会聚的平板波导和在相邻波导之间路径长度差△L恒定的阵列波导构成。输入光射入第一个平板波导并激励阵列波导,光通过阵列波     

OBS网络中基于扩展Benes矩阵的节点串扰分析

光突发交换(OBS)的提出,一定程度上满足了对高速业务的需求,但由于交换结构中光路器件自身的特性以及信号的相互作用,其内部存在严重的串扰问题,阻碍了通信的进行,极大地限制了光突发交换的性能。为了进一步研究OBS光网络节点结构中的串扰问题,仿真模拟了OBS网络中基于扩展Benes光交换矩阵的节点串扰情况,证明了OBS网络节点结构中,光交换矩阵本身、输入输出光纤数和每根光纤中的复用波长数都会不同程度的引起串扰的变化,从而影响整个光通信网络的质量。     

Reconfigurable OADM and OXC designed by a new optical switch

A new dynamically selective optical add/drop multiplexer (OADM) and optical cross-connect (OXC) configuration for dense wavelength division multiplexed (DWDM) networks are proposed. The selective devices are based on fiber Bragg gratings (FBGs), single-sided micro-mirror optical switches (OSWs), and optical circulators (OCs). They are flexible, expandable, and high capacity in DWDM networks if the basic units are cascaded in series. In this paper, fiber collimators in coupling are analyzed in order to characterize the insertion loss and output power equalization in OADM and OXC. “Off-the-shelf” DWDM communication products are used for analysis; as a result, the main insertion loss in the system comes from circulators while the maximum insertion loss deviation comes mainly from FBGs and micro-mirrors. As compared to the other existing reconfigurable OADMs and OXCs, the number of mirrors in the optical switch could be dramatically reduced. The reliability of optical switch operation, therefore, can be enhanced.     

Optical cross-connect system incorporated with newly developedoperation and management system

The optical cross-connect (OXC) system described in this paper increases the operation flexibility and reliability of the trunk-line optical networks used for data communication. It features an OXC node comprised of a photonic switching network and a conventional electric switching network that are connected hierarchically. The operation and management scheme proposed for this OXC system uses the concept of an optical path and an optical section. The OXC system allows hitless network reconfiguration by switching the photonic switches gradually and without interference effects. An experimental OXC network showed that a broken optical path is restored, by rerouting, within 50 ms. Experiments using a LiNbO₃ 8×8 photonic switch matrix also showed that the OXC system provides photonic hitless switching. These results confirm the feasibility of flexibly reconfigurable and fast-restorable OXC systems     

Novel architectural schemes for wavelength conversions in optical cross connect systems

This paper proposes simple, cost-effective schemes for wavelength conversions in optical cross-connect (OXC) systems using wavelength-fixed light sources and an optical space switch, and provides improved performance in stability and conversion range of wavelengths and channel spacing. In addition, the schemes avoid the need for the wavelength locking control that is generally needed after changing the probe beam wavelength from one wavelength to another. The technical feasibility of the proposed pre-fix scheme is investigated in terms of probe beam power through experiment of wavelength conversions based on the cross-gain modulation. The results show that the proposed wavelength conversion scheme in OXC allows a ±4 dB deviation in the probe beam power to afford a 2 dB power penalty deviation from the minimum power penalty. As long as the insertion loss deviation of an optical space switches are within ±4 dB, the proposed pre-fix scheme can be used for wavelength conversions in OXC systems for a 2 dB power penalty deviation, whereas the proposed post-fix scheme does not require an optical space switch.     

P比特光交换节点研究

光网络中引入全光交换技术可以无需进行光电光转换和电信号处理,使网络具备透明性,大大降低节点的复杂性和节点成本。多粒度交换节点减小了交换矩阵的规模,降低了交换矩阵的复杂性,是波分复用（WDM）网络节点发展的一个方向。随着正交频分复用（OFDM）技术的引入,带宽可变的节点技术得到了越来越广泛的关注。文章介绍了传统的基于波长的光交叉连接器（OXC）交换结构、多粒度交换结构,以及基于正交频分复用/单载波频分复用（OFDM/SCFDM）的节点交换结构,并通过实验对基于带宽可变的可重构的光分插复用器（ROADM）、OXC节点技术进行了验证。在实验中提出的基于子波带的交换结构中,节点容量达到了P比特量级。     

应用于全光网络的光开关技术研究

随着信息技术、光通信技术的发展,全光网络（AON）成为信息时代的主流,OXC光交叉连接）、OADM（光分插复用）是全光网络的核心,而光开关是实现OADM、OXC的关键器件,因此研制应用于全光网络的光开关具有重大意义。重点对光开关在OADM、OXC中的应用及光开关可能采取的方案进行研究,认为在未来的光纤通信集成电路（IC）的芯片之争中,微机电系统（MEMS）光开关技术举足轻重。     

A Novel Integrated Multistage 2-D MEMS Optical Switch With Spanke–Benes Architecture

Due to the emergence of high-capacity wavelength-division multiplexing transmission systems, new optical cross-connect (OXC) architectures that make a large number of fiber/wavelength counts to switch the signal in the optical domain are needed. Optical microelectromechanical system (MEMS) switches are regarded as the most promising optical switch technology to achieve such functionalities. In this paper, we propose a novel integrated multistage two-dimensional (2-D) MEMS optical switch design with Spanke-Benes architecture and compare it with the conventional crossbar architecture, the L-switching architecture, and Shuffle-Benes architecture. Our proposed architecture is very suitable for building large-port-count 2-D MEMS switches and achieves much better performance in terms of beam divergence loss, longest optical path, mirror radius, substrate size, port-to-port repeatability, and power consumption than the other three architectures. Furthermore, compared with the 2-D conventional crossbar switch commercially available now, the proposed architecture can save 50% mirrors, shorten 87.5% longest optical path, minify 65% mirror radius, and shrink 90% substrate size.     

OXC及OADM网络节点的研究

分析了光交叉连接（ＯＸＣ）设备和光分插复用（ＯＡＤＭ）设备在ＷＤＭ全光网络中的作用。说明了它们是克服网络节点瓶颈问题的有效方法。设计了一种有一个ＯＸＣ节点及六个ＯＡＤＭ节点的网络结构。提出了它的四个关键技术问题的解决方案。     

光交叉连接/光分插复用器的应用前景

文章通过比较波分复用、光时分复用和光码分多址复用技术,得出波分复用是当前光网络发展主流的结论。重点分析了在波分复用系统中,交叉连接/光分插复用器在骨干网、城域网和自动交换光网络中的应用,指出在下一代网络中,光交叉连接/光分插复用器将会有很好的发展前景。     

全光网的关键器件——光交叉连接器与光分插复用器

全光网（AON,all-optical network）以波长路由光交换技术和波分复用传输技术（WDM）为基础,它的网络节点由光分插复用器和光交叉连接器构成,能在光域上实现高速信息流的传输、交换、路由和故障恢复等功能。光交叉连接器（OXC）与光分插复用器（OADM）是全光网中最重要的网络器件,是真正实现全光网关键性功能的必要前提,也是目前国内外光通信器件厂商研究和开发的热点。本文结合全光网的发展,介绍了光交叉连接器（OXC）与光分插复用器（OADM）的基本原理、性能指标,对不同的节点结构进行了比较与讨论,并介绍与比较了目前国内外厂商的主要产品。