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optical switching will innovate intra data center networks [Invited Tutorial]

JOURNAL OF optical communicationS AND NETWORKING 2024年第1期16卷 A1-A23页

作者： Sato, Ken-ichi Natl Inst Adv Ind Sci & Technol Umezono 1-1-1 Tsukuba Ibaraki 3058568 Japan

Reflecting the recent slow-down in Moore's law and the proliferation of artificial intelligence/machine learning workloads, the performance and energy consumption of networks are becoming barriers in high-performance computing (HPC) and data centers. optical switches are expected to break these barriers, and indeed their introduction has recently commenced in data centers. This paper discusses how optical switching technologies can innovate future intra data center networks. Hyperscale data centers are much bigger in scale, and network requirements are slightly different from those of HPC. This paper focus on data center networks, since the impact of optical technologies will be more significant in data centers than in HPC. In addition to the scale issue, important metrics to be considered for network design are traffic characteristics and latency, both of which are highlighted in this paper. For hybrid (electrical packet and optical circuit) switching networks, the target latency for the optical circuit switch network (connection setup/teardown time) is shown to be around 10 mu s, and the needed technologies are clarified and verified by experiments. The optical switch can simplify the present multi-tier switching network above tier-1 switches into a single tier configuration, which is possible with the development of efficient large port count optical switches. Among the different switching architectures, combining the different dimensions of space and wavelength is shown to be one of the best solutions. Fast switching needs fast device response time. Si photonics devices using Mach-Zehnder interferometers or ring-resonator-based switches and tunable filters are the most promising candidates;they offer cost-effective mass-production and fast operation and so are excellent candidates for the optical switches envisaged. Another critical technology to maximize the benefits of optical switches is a simple and low-latency control mechanism. Different approaches have be

关键词： optical fiber communication Data centers Moore's Law optical switches

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Fast WDM provisioning with minimal probing: the first field experiments for DC exchanges

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JOURNAL OF optical communicationS AND NETWORKING 2024年第2期16卷 233-242页

作者： Nishizawa, Hideki Mano, Toru de Lima, Thomas Ferreira Huang, Yue-Kai Wang, Zehao Ishida, Wataru Kawashima, Masahisa Ip, Ezra D'Amico, Andrea Okamoto, Seiji Inoue, Takeru Anazawa, Kazuya Curri, Vittorio Zussman, Gil Kilper, Daniel Chen, Tingjun Wang, Ting Asahii, Koji Takasugi, Koichi NTT Network Innovat Labs Kanagawa Japan NEC Labs Amer Princeton NJ 08540 USA Duke Univ Durham NC 27708 USA NTT Software Innovat Ctr Tokyo Japan NTT IOWN Dev Ctr Tokyo Japan Politecn Torino Turin Italy Columbia Univ New York NY 10027 USA Trinity Coll Dublin CONNECT Ctr Dublin Ireland NEC Corp Ltd Chiba Japan

There are increasing requirements for data center interconnection (DCI) services, which use fiber to connect any DC distributed in a metro area and quickly establish high-capacity optical paths between cloud services and mobile edge computing and the users. In such networks, coherent transceivers with various optical frequency ranges, modulators, and modulation formats installed at each connection point must be used to meet service requirements such as fast-varying traffic requests between user computing resources. This requires technology and architectures that enable users and DCI operators to cooperate to achieve fast provisioning of WDM links and flexible route switching in a short time, independent of the transceiver's implementation and characteristics. We propose an approach to estimate the end-to-end (EtE) generalized signal-to-noise ratio (GSNR) accurately in a short time, not by measuring the GSNR at the operational route and wavelength for the EtE optical path but by simply applying a quality of transmission probe channel link by link, at a wavelength/modulation-format convenient for measurement. Assuming connections between transceivers of various frequency ranges, modulators, and modulation formats, we propose a device software architecture in which the DCI operator optimizes the transmission mode between user transceivers with high accuracy using only common parameters such as the bit error rate. In this paper, we first implement software libraries for fast WDM provisioning and experimentally build different routes to verify the accuracy of this approach. For the operational EtE GSNR measurements, the accuracy estimated from the sum of the measurements for each link was 0.6 dB, and the wavelength-dependent error was about 0.2 dB. Then, using field fibers deployed in the NSF COSMOS testbed, a Linux-based transmission device software architecture, and transceivers with different optical frequency ranges, modulators, and modulation formats, the fast WDM p

关键词： optical devices Adaptive optics Wavelength division multiplexing optical modulation optical fiber communication Computer architecture optical variables measurement

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X-NEST: A Scalable, Flexible, and High-Performance Network Architecture for Distributed Machine Learning

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JOURNAL OF LIGHTWAVE TECHNOLOGY 2021年第13期39卷 4247-4254页

作者： Lu, Yunfeng Gu, Huaxi Yu, Xiaoshan Li, Peng Xidian Univ State Key Lab Integrated Serv Networks Xian 710071 Peoples R China State Key Lab Math Engn & Adv Comp Wuxi 214125 Jiangsu Peoples R China

In a large-scale distributed machine learning system, the interconnection network between computing devices has an important impact on performance in the training of neural network models. The current expansion of training data and model size has led to a rapid increase in the number of computing devices used in distributed machine learning systems, which places higher demands on network scalability. In addition, the synchronization algorithms used for data exchange between computing devices have different communication topologies, and traditional electrical networks have difficulty matching them due to their fixed network topology. Neural network models and model partitioning methods can also affect the amount of communication between devices, but the overprovisioned bandwidth of traditional electric networks incurs unnecessary costs. To address these issues, we propose a scalable, flexible, and high-performance network architecture called X-NEST. The flexibility of optical switching devices allows X-NEST to dynamically change its topology and the number of links between devices according to traffic pattern variations, thereby improving network performance and resource utilization. Although changes in the connection relationships between devices depend on the controller, the simple and flexible control plane of X-NEST can quickly respond to network communication requirements. Extensive analytical simulations using different traffic patterns demonstrate that X-NEST copes well with the communication characteristics of various synchronization algorithms.

关键词： Synchronization optical switches Microswitches Topology Network topology Micromechanical devices Parallel processing Data centers machine learning optical interconnects topology

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Low loss polymeric spot-size converter with two-step index transition cladding for fiber-to-chip connection 27

Low loss polymeric spot-size converter with two-step index t...

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27th OptoElectronics and communications Conference/International Conference on Photonics in switching and computing, OECC/PSC 2022

作者： Ma, Qiang Ma, Lin Zhuang, Yudi Li, Heyuan He, Zuyuan Shanghai Jiao Tong University State Key Laboratory of Advanced Optical Communication Systems and Networks Shanghai200240 China Zhejiang Lab Hangzhou311121 China

We propose a low loss polymeric spot-size converter with two-step index transition cladding for fiber-to-chip connection. The device can simultaneously achieve a coupling loss of 1.84 dB and strictly single-mode opera... 详细信息

ISBN: (数字)9784885523366

ISBN: (纸本)9784885523366

关键词： Optoelectronic devices

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optical Wireless Network Architecture

Optical Wireless Network Architecture

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2022 27th OptoElectronics and communications Conference (OECC) and 2022 International Conference on Photonics in switching and computing (PSC)

作者： Vincent W.S. Chan Joan and Irwin Jacobs Chair Professor Department of Electrical Engineering and Computer Science Claude E. Shannon Communication and Network Group Research Laboratory of Electronics Steve Schwarzman College of Computing AI and Decision System Sector Massachusetts Institute of Technology. President IEEE Communications Society 2020&#x2013 2021.

ISBN: (数字)9784885523366

ISBN: (纸本)9781665486064

optical wireless network has the potential to serve space-space, space-terrestrial/aircraft, aircraft-aircraft, data centers and metropolitan area networks. This paper addresses architecture features necessary for these networks. Free space optical (FSO) networks have two dimensions that are not encountered in fiber networks and that is: (1) its ability to connect without pre-deployment of infrastructures and (2) the ability to reconfigure its connection topology by beam steering in time scales of mS-S to adapt to traffic loads, switching node states and atmospheric conditions. This paper presents a multi-layer approach to optical wireless networks and how the architecture can be tuned to applications.

关键词： optical fibers Network topology Metropolitan area networks Wireless networks optical switches Computer architecture Telecommunication traffic

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Hierarchical and reconfigurable optical/electrical interconnection network for high-performance computing

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JOURNAL OF optical communicationS AND NETWORKING 2020年第3期12卷 50-61页

作者： Zhao, Zuoqing Guo, Bingli Shang, Yu Huang, Shanguo Beijing Univ Posts & Telecommun Inst Informat Photon & Opt Commun Sch Optoelect Informat Beijing 100876 Peoples R China

Compared with electrical packet switches, optical switching technology could enable a more desirable high-performance computing (HPC) system with lower power consumption, lower delay, higher bandwidth, and more flexibility. In this article, we designed a hierarchical and reconfigurable optical/electrical HPC interconnection network. The traffic matrix of the target task can be decomposed into multiple matrix groups that are executed in parallel, and the network topology in each layer can be reconfigured according to the subtraffic matrix associated with this layer. For interlayer cross-connection, we use a shuffle network to offer a direct optical bypass for a huge aggregated amount of interlayer communication requirements, as well as multiple light paths. We propose a reconfiguration optimization algorithm and routing algorithm to optimize network performance. Simulation results show that, with the proposed architecture and algorithms, the average path length per unit of communication intensity is minimized by 13.7%-52.4%, the delay is reduced by more than 14.8%, and throughput is improved by 33% at least compared withMesh, Torus, and Dragonfly. (C) 2020 optical Society of America

关键词： Algorithms Circuit switching Network topology optical circuits Packet switching Routing algorithms

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Investigating the use of Semiconductor Nanowires for Neural networks

Investigating the use of Semiconductor Nanowires for Neural ...

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作者： Serafini, Alfredo Lund University

学位级别：硕士

In this work, we intend to employ nanowires for the realisation of an artificial neuron which can be used to design a neural network that will guide the new generation of non-von Neumann architectures such as Neuromorphic computing. Possible applications are strongly related to Neuromorphic architectures and artificial intelligence, such as high-performance computers, robotics hardware and autonomous drones. Here, we aim to design a device that can perform as a node in an optically communicating neural network. We employ nanowires to form a single artificial neuron by coupling a receiver and a transmitter of optical signals, together with a transistor as an in-between control element. Based on this configuration, we find optimal optical properties for our desired neural network communication. The node-to-node communication relies on the strength of the connection known as weights. The connection strength can be tailored by the position and rotation of the individual nanowires making up the nodes and layers; however, this might set some correlations and limitations on the weights. We frame our main research questions as a set of hypotheses that we test by numerical experiments using the finite-difference time-domain (FDTD) method. The FDTD method is one of many numerical methods that exist to tackle this type of electromagnetic simulation. Among the valid alternatives are the finite element method and the method of the moment. However, we decided on the FDTD method because it is the one that best suits our needs to perform electromagnetic simulation on nanowires and to study a node-to-node communication. We split our study and perform separate simulations on the receiver and transmitter. During the simulation of the receiver, we sweep the incoming light angle to study the absorption difference between two distinct depletion regions. The difference in absorption between the two regions yields a potential difference that allows switching on and off the transistor that

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基于以太无损网络的智算中心光网络架构研究(特邀)

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光通信研究 2024年第5期5期(18)卷 35-40页

作者：翟锐李壮志侯广营马艺嘉徐化朗中国联合网络通信有限公司山东省分公司济南250002

【目的】近年来,生成式人工智能(AIGC)掀起了人工智能革命,智算中心(ICC)的网络联接也随之向超高带宽、智能无损和算网融合等方向发展,因此ICC光网络需要降低卡间通信时间,以提升数据访问效率。【方法】文章针对ICC场景光网络的组网架... 详细信息

【目的】近年来,生成式人工智能(AIGC)掀起了人工智能革命,智算中心(ICC)的网络联接也随之向超高带宽、智能无损和算网融合等方向发展,因此ICC光网络需要降低卡间通信时间,以提升数据访问效率。【方法】文章针对ICC场景光网络的组网架构进行了研究,实现了大带宽、低时延和中央处理器(CPU)效率高的无损网络,满足了ICC的大模型训练和推理需求。文章详细分析了ICC的流量分布特征和人工智能(AI)大模型训练组网场景下的通信流特征,深入研究了基于远程直接内存访问(RDMA)的以太无损传输方案的ICC组网架构,并最终在ICC场景下进行了组网实践和时延测试。【结果】文章提出的基于以太网的RDMA(RoCE)传输方案具备基于优先级的流控制、显示拥塞通知、增强传输选择和数据中心桥能力交换协议(DCBX)等能力,可实现数据中心内基于以太协议的无损传输。测试结果显示,使用RoCE协议的传输时延大约稳定在1μs,并且显著优于互联网广域RDMA协议(iWARP)。【结论】文章基于智算场景下的流量特征分析,深入研究了ICC的无损以太网络关键特性,利用RDMA技术实现了ICC场景下光交换网络传输效率的提升,并提出了一种在ICC大模型推理场景下的无损以太网络方案,为RDMA技术在智算场景下的应用探索出了可行的方向。

关键词：长距直接内存访问以太无损网络智算中心光交换

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FSO/RF-FSO Radar Perform Research over Fisher-Snedecor Fading Theory for 5G Mobile Application

FSO/RF-FSO Radar Perform Research over Fisher-Snedecor Fadin...

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International Conference on Contemporary computing and Informatics (IC3I)

作者： Harveer Singh Kushnain Kaur Department of Computer Science Engineering Sanskriti University Mathura Uttar Pradesh India Department of Computer Science & Engineering Chandigarh Engineering College Jhanjeri India

For 5Mobile communication back networking, free-space optically (FSO) lines include a limited, semi alternative to fiber optic connections. We propose a micrometer (The use) High frequency link as a backup for FSO-based backbone networks. By switching between main Fso systems and indeed the secondary Radio wave link, it is possible to create an uninterrupted and reliable network connectivity. When the predominant link is disrupted by ambient occlusion, the ancillary link maintains connectivity because of Millimeter - wave RF link has characteristics that are parallel to ambient noises. We also provide simple mathematical formulae for a range of performance measurements, such as path loss and mean bit - error, to objectively quantify the gains (BER). Our findings show that, in terms of path loss and Snr, the FSO/RF-FSO topology outperforms a single FSO connection. An enhanced and the reverse (AF) relay using the overall energy scaling technique establishes a dual mixing RF-FSO link. A measure used to quantify illumination is called reflectance.

关键词： optical fibers Reflectivity Recurrent neural networks optical switches Topology Regression analysis Radar applications

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Towards 6G wireless communication networks:vision, enabling technologies, and new paradigm shifts

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Science China(Information Sciences) 2021年第1期64卷 5-78页

作者： Xiaohu YOU Cheng-Xiang WANG Jie HUANG Xiqi GAO Zaichen ZHANG Mao WANG Yongming HUANG Chuan ZHANG Yanxiang JIANG Jiaheng WANG Min ZHU Bin SHENG Dongming WANG Zhiwen PAN Pengcheng ZHU Yang YANG Zening LIU Ping ZHANG Xiaofeng TAO Shaoqian LI Zhi CHEN Xinying MA Chih-Lin I Shuangfeng HAN Ke LI Chengkang PAN Zhimin ZHENG Lajos HANZO Xuemin (Sherman) SHEN Yingjie Jay GUO Zhiguo DING Harald HAAS Wen TONG Peiying ZHU Ganghua YANG Jun WANG Erik G.LARSSON Hien Quoc NGO Wei HONG Haiming WANG Debin HOU Jixin CHEN Zhe CHEN Zhangcheng HAO Geoffrey Ye LI Rahim TAFAZOLLI Yue GAO H.Vincent POOR Gerhard P.FETTWEIS Ying-Chang LIANG National Mobile Communications Research Laboratory School of Information Science and EngineeringSoutheast University Purple Mountain Laboratories Shanghai Institute of Fog Computing Technology (SHIFT) ShanghaiTech University Research Center for Network Communication Peng Cheng Laboratory State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications National Engineering Laboratory for Mobile Network Technologies Beijing University of Posts and Telecommunications National Key Laboratory of Science and Technology on Communications University of Electronic Science and Technology of China (UESTC) China Mobile Research Institute School of Electronics and Computer Science University of Southampton Department of Electrical and Computer Engineering University of Waterloo Global Big Data Technologies Centre (GBDTC) University of Technology Sydney School of Electrical and Electronic Engineering The University of Manchester LiFi Research and Development Centre Institute for Digital CommunicationsSchool of EngineeringThe University of Edinburgh Huawei Technologies Canada Co. Ltd. Huawei Technologies Department of Electrical Engineering (ISY) Link?ping University Institute of Electronics Communications & Information Technology (ECIT)Queen's University Belfast State Key Laboratory of Millimeter Waves School of Information Science and EngineeringSoutheast University School of Electrical and Computer Engineering Georgia Institute of Technology 5G Innovation Centre University of Surrey Princeton University Vodafone Chair Mobile Communications Systems Technische Universit?t Dresden Center for Intelligent Networking and Communications (CINC) University of Electronic Science and Technology of China (UESTC)

The fifth generation(5G) wireless communication networks are being deployed worldwide from 2020 and more capabilities are in the process of being standardized, such as mass connectivity, ultra-reliability,and guaranteed low latency. However, 5G will not meet all requirements of the future in 2030 and beyond, and sixth generation(6G) wireless communication networks are expected to provide global coverage, enhanced spectral/energy/cost efficiency, better intelligence level and security, etc. To meet these requirements, 6G networks will rely on new enabling technologies, i.e., air interface and transmission technologies and novel network architecture, such as waveform design, multiple access, channel coding schemes, multi-antenna technologies, network slicing, cell-free architecture, and cloud/fog/edge computing. Our vision on 6G is that it will have four new paradigm shifts. First, to satisfy the requirement of global coverage, 6G will not be limited to terrestrial communication networks, which will need to be complemented with non-terrestrial networks such as satellite and unmanned aerial vehicle(UAV) communication networks, thus achieving a space-airground-sea integrated communication network. Second, all spectra will be fully explored to further increase data rates and connection density, including the sub-6GHz, millimeter wave(mmWave), terahertz(THz),and optical frequency bands. Third, facing the big datasets generated by the use of extremely heterogeneous networks, diverse communication scenarios, large numbers of antennas, wide bandwidths, and new service requirements, 6G networks will enable a new range of smart applications with the aid of artificial intelligence(AI) and big data technologies. Fourth, network security will have to be strengthened when developing 6G networks. This article provides a comprehensive survey of recent advances and future trends in these four aspects. Clearly, 6G with additional technical requirements beyond those of 5G will enable f

关键词： 6G vision network architecture air interface and transmission technologies space-air-ground-sea integrated network all spectra artificial intelligence network security

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