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.     

基于磁调谐光纤Bragg光栅的全光纤型多路分/插复用器

提出了一种新型的用作多信道切换的光分／插复用器,它由多个可调谐光纤Ｂｒａｇｇ光栅、一对光纤环行器、ＷＤＭ复用器和解复用器构成。讨论了该分／插复用器的结构、性能和特点。利用磁极间磁场力使光纤光栅产生显著的波称偏移。用可编程磁极来调控光栅的波长偏移。其信道波长调谐速度快,装置无需外加能源即可保护信道波长的偏移。     

Fiber-grating add–drop reconfigurable multiplexer with multichannel using in bi-directional optical network

A bi-directional reconfigurable scheme of multichannel-selective optical add–drop multiplexer (OADM) is proposed in this paper. With only small wavelength channel tuned range, the proposal applies fiber Bragg gratings (FBGs) and multiport optical circulators (MOCs) to build a bi-direction reconfigurable OADM which can deal with full channels without the receiving signal having wavelength-interleaved. Moreover, it is easier and more flexible to extend wavelength channels by cascading additional FBGs. The magnitudes of homodyne and heterodyne crosstalks are analyzed for evaluating the performance of the proposed BOADM. Also, the power equalization of each signal in the add–drop and output ports is managed properly by implementing filters. As a result, the BOADM will be found in wide applications in dense wavelength-division multiplexing (DWDM) optical networks and in multiwavelength crossconnects (WXCs).     

一种基于光纤Bragg光栅的全光纤分/插复用器

研制了用于ＷＤＭ全光网的全光纤型分／插复用器,由两个相同的光纤环行器和串接其间的光纤Ｂｒａｇｇ光栅组成。其中光纤Ｂｒａｇｇ光栅是用紫外光直写方式在普通单模光纤上制成。文中给出了该复用器的上／下路端口隔离度和信道插入抽耗等主要测量结果。其特点是结构简单,可实现信道波长再利用,从而提高网络的灵活性。     

城域波分复用传输系统

随着城域传输网的演变和对带宽的要求，密集波分复用技术将由长途骨干网进入城域传输网。本文对城域DWDM系统的组成、波长的采用、OADM结构、波长转换器特性、光放大器的采用、波长优化、网络保护机制等进行了简要的分析。     

取样光栅的反射谱特性及其应用

本文基于取样光栅的独特反射谱特性,对其作为光子器件如DBR激光器、波分复用/解复器和光插分复用器的结构图作了探讨.通过比较得知,用取样光栅构成的新型光子学器件比用单纯的光纤光栅构成的光子学器件在未来的密集型波分复用(DWDM)光纤通信系统中更有实用价值.     

The Berlin City Ring—a Testbed for Future Metropolitan Networks

Dense wavelength division multiplexing (DWDM) is the key technology for future data transport. It combines transmission of data rates up to several Tb/s [1] with an overall transparency to data format and bit rate. The expected huge bandwidth demand in the near future requires an adaptability of DWDM transmission technology to metropolitan networks. Therefore, dynamically configurable DWDM transmission technology for bit rates up to 10 Gb/s has been investigated in a field trial in Berlin. This field trial is part of the KomNet research project. It is the goal of this field trial to optimize DWDM systems to metropolitan network requirements. Several aspects are in this paper: (i) A network simulation tool is described which helps to enlighten the profitability of statically and dynamically configured network nodes. (ii) A newly developed technology to add and drop single-wavelength channels is explained. (iii) The scalability of the approach is demonstrated with an aggregate capacity of 0.8 Tb/s. The equipment has already been installed in the field and is ready for experiments.     

基于MZI和取样光栅的可调谐光分插复用器

提出一种基于马赫-曾德尔干涉仪(MZI)和取样光纤布拉格光栅(SFBG)的新型光分插复用器(OADM),它由两个并联马赫-曾德尔干涉仪和四个取样光纤布拉格光栅组成.对该光分插复用器的输出特性进行了理论仿真,研究得出通道间隔为0.8nm时下载和输出端口的光谱特性,研究发现干涉仪的臂长差和取样光栅的中心波长差是决定光分插复用器输出特性的主要因素.调节一个马赫-曾德尔干涉仪上的臂长差和取样光栅的中心波长,可以实现信号下载可调功能或直通功能.     

集成化光上下路复用器的研究进展

密集波分复用(DWDM)已经成为光纤通信的主要发展方向,光上下路分插复用器(OADM)作为WDM网络中的关键技术,它的优劣将直接影响通信网络的性能.侧重于从器件的角度对OADM的功能和发展现状进行介绍,并对其构成的关键器件的发展进行了概述.     

光分插复用网元节点的设计和实验研究

提出了一种用于光传送网（OTN）的光分插复用（OADM）网元（NE）节点的体系结构，采用模块化方法，划分并设计出各功能模块。研制出可以同时支持8个波长动态分插复用的可重构OADM NE节点，提供2个双向全光网接口和网络管理接口。     

Architecture and design of optical channel protected ring networks

In this paper, different optical ring architectures are considered and the optical add/drop multiplexer (OADM) functional architecture is described. In addition, different aspects of ring network design and their impact on the network architecture are discussed     

Design considerations in optical add/drop multiplexers based ongrating-assisted null couplers

The performance of a fully optimized optical add/drop multiplexer (OADM), based on null couplers and tilted Bragg gratings, is studied in detail. It is shown that maximization of the device performance involves three main optimization steps. First, the waveguide asymmetry (V₂ /V₁ ratio) should be optimized in order to minimize the extinction ratio of the unwanted mode at the null coupler waist. Second, the coupler taper shape should he optimized in order to further minimize the aforementioned extinction ratio. Third, the grating tilt angle and relative width can be also optimized to give negligible backreflections at the input port and minimize radiation losses. The results show that the proposed high-performance OADM configuration can meet stringent telecom specifications     

Dynamic OADM Using Tunable Sampled Bragg Gratings Based on Vernier Effect

A novel dynamic optical add-drop multiplexer（OADM） scheme using tunable sampled fiber Bragg gratings（SFBG） by Vernier effect is firstly proposed. In this scheme, broad wavelength tuning range is achieved by only slightly adjusting the SFBG, the wavelength tuning of OADM will be faster than traditional dynamic OADM.     

基于马赫-曾德尔干涉仪和光纤光栅的光分插复用器

光分插复用器(OADM)是波分复用(WDM)系统中的关键器件之一。提出了一种结构新颖的基于马赫-曾德尔(M—Z)干涉仪和光纤光栅(FBG)的光分插复用器，它由两个三端口光环形器、一个光纤光栅和一个马赫-曾德尔干涉仪组成，马赫-曾德尔干涉仪起着光开关的作用。对光分插复用器的输出特性进行了实验研究，实验中调节干涉仪的臂长差，可以实现信号的上下载或直通功能，上下载时通道的隔离度大于20dB。这种结构的光分插复用器具有结构简单、体积小、价格低等优点，在波分复用技术中具有实际应用价值。     

Self-Clocked All-Optical Add/Drop Multiplexer for Asynchronous CDMA Ring Networks

In this paper, we demonstrate a novel self-clocked code-drop unit for incoherent optical code-division multiple-access (CDMA) networks. The unit is based on an all-optical thresholder with internal wavelength conversion that creates a control signal for the drop gate from the incoming data stream. This architecture does not require an external clock signal for drop operation and can be used in asynchronous ring networks. The proposed unit is experimentally demonstrated for two-dimensional time-wavelength optical CDMA codes at a bit rate of 2.5 Gbit/s with two different types of drop gates: terahertz optical asymmetric multiplexer and nonlinear fiber-based loop mirror. Error-free operation is achieved in both configurations. The development of a self-clocked add/drop multiplexer demonstrates a novel concept of asynchronous node operation in multiple access networks.      

城域DWDM光网络技术方案研究

主要论述了DWDM光复用、DWDM可配置光环和DWDM网状网等3种主要的DWDM城域核心组网方案，分析了各种方案的特点和应用范围。     

ROADM全光交换网络关键技术发展与应用展望

介绍了可重构光分插复用器（reconfigurable optical add/drop multiplexer，ROADM）网络的发展历程、ROADM技术方案以及国内ROADM网络的部署情况。全面阐述了ROADM关键技术的发展方向，包括光交叉连接（optical cross-connect，OXC）设备、高维度波长选择开关（wavelength selected switch，WSS）、波长无关/方向无关/竞争无关ROADM （colorless/directionless/contentionless ROADM，CDC-ROADM）、400 Gbit/s FlexGrid ROADM、下一代波长交换光网络（next-generation wavelength switched optical network，WSON2.0）智能控制平面技术。分析了现有ROADM网络应用场景与技术发展趋势，展望了ROADM全光交换网络未来发展前景。     

Optical add-drop multiplexers with low crosstalk

We propose and demonstrate three new optical add-drop multiplexer (OADM) architectures with simple and compact configuration and excellent crosstalk performance. The OADMs use a single multiport optical circulator and either one or two narrow-band fiber Bragg gratings, depending on the crosstalk requirement     

光分插复用设备的节点结构与组网研究

光分插复用设备（OADM）是光传送网中的重要网元，本文提出了OADM的实现方法与设计原则，给出了实现OADM中的若干关键技术问题，相应的解决方法以及利用OADM进行长距离传输与组网的实验研究结果。     

MOSAIC: a multiwavelength optical subcarrier multiplexed controllednetwork

The experimental demonstration of MOSAIC, a reconfigurable WDM add/drop network with subcarrier multiplexed control, is presented. The MOSAIC network implements the optical layer protocol to support bit-rate transparent multichannel lightpaths. Two types of add/drop multiplexers are implemented and combined in a three-node experiment. Multihop lightpaths are established giving an end-to-end bit error rate of better than 10^-9 at 1.2 Gbps. The reconfigurable add/drop multiplexer is based on a novel dilated 2×2 acoustooptic filter switch crossconnect and an analog optoelectronic crossconnect that drives a ten-wavelength laser array transmitter up to 2.5 Gbps per wavelength. The fixed wavelength add/drop multiplexer utilizes a fast digitally tunable laser transmitter. Both add/drop multiplexers support bit-rate transparent 2R optoelectronic regeneration as well as wavelength translation. Subcarrier multiplexing on each wavelength is used to support channel state monitoring and channel equalization as well as transmission of digital network control information. Systems experiments demonstrate cascaded 2R optoelectronic regeneration with wavelength translation and cascaded multichannel optical switching with up to seven hops. It is shown that combining cascaded 2R optoelectronic regeneration with cascaded multichannel optical switching can be used to balance jitter accumulation and amplified spontaneous emission generated amplitude noise to yield high signal-to-noise ratio for lightpaths