All-optical computing based on convolutional neural networks

The rapid development of information technology has fueled an ever-increasing demand for ultrafast and ultralow-en-ergy-consumption computing.Existing computing instruments are pre-dominantly electronic processors,which use elec-trons as information carriers and possess von Neumann architecture featured by physical separation of storage and pro-cessing.The scaling of computing speed is limited not only by data transfer between memory and processing units,but also by RC delay associated with integrated circuits.Moreover,excessive heating due to Ohmic losses is becoming a severe bottleneck for both speed and power consumption scaling.Using photons as information carriers is a promising alternative.Owing to the weak third-order optical nonlinearity of conventional materials,building integrated photonic com-puting chips under traditional von Neumann architecture has been a challenge.Here,we report a new all-optical comput-ing framework to realize ultrafast and ultralow-energy-consumption all-optical computing based on convolutional neural networks.The device is constructed from cascaded silicon Y-shaped waveguides with side-coupled silicon waveguide segments which we termed“weight modulators”to enable complete phase and amplitude control in each waveguide branch.The generic device concept can be used for equation solving,multifunctional logic operations as well as many other mathematical operations.Multiple computing functions including transcendental equation solvers,multifarious logic gate operators,and half-adders were experimentally demonstrated to validate the all-optical computing performances.The time-of-flight of light through the network structure corresponds to an ultrafast computing time of the order of several picoseconds with an ultralow energy consumption of dozens of femtojoules per bit.Our approach can be further expan-ded to fulfill other complex computing tasks based on non-von Neumann architectures and thus paves a new way for on-chip all-optical computing.

Research on Fault Repair Method of All-Optical Network Based on SDN

All-optical network,as a new backbone network,is featured with high speed and large capacity transmission.It may be out of order due to various faults while providing high-performance transmission service,thus more effective fault repairing methods are required.A routing and wavelength assignment method based on SDN is designed and analyzed from the perspective of service function chaining in this paper.A multi-objective integer linear programming model based on impairment-aware and scheduling time is constructed by combining the unified control of control plane with the resource allocation mode of service function virtualization.Meanwhile,an improved Firefly Algorithm is adopted to solve the model for obtaining a better scheduling scheme,so as to the resources are allocated on-demand in a more flexible and efficient way,which effectively improved the self-recovery capability of the network.In the simulation experiments,Through the comparison between the method proposed and methods based on centralization and distribution,method proposed in the paper is superior to the compared ones in the indexes of survivability,blocking probability,link recovery time,and presents a better scheduling performance,makes the system has stronger ability of self-healing in the face of failure.

Intelligent Space All-Optical Network Technology

Microwave transmission in a space network is greatly restricted due to precious radio spectrum resources. To meet the demand for large-bandwidth, global seamless coverage and on-demanding access, the Space All-Optical Network(SAON) becomes a promising paradigm. In this paper, the related space optical communications and network programs around the world are first briefly introduced. Then the intelligent Space All-Optical Network(i-SAON), which can be deemed as an advanced SAON, is illustrated, with the emphasis on its features of high survivability, sensing and reconfiguration intelligence, and large capacity for all optical load and switching. Moreover, some key technologies for i-SAON are described, including the rapid adjustment and control of the laser beam direction, the deep learning-based multi-path anti-fault routing, the intelligent multi-fault diagnosis and switching selection mechanism, and the artificial intelligence-based spectrum sensing and situational forecasting.

Hybrid WDM/TDM PON system employing an all-optical wavelength converter

A new hybrid WDM/TDM passive optical network （PON） implemented by using all-optical wavelength converters （AOWCs） is proposed. The AOWCs are based on the cross-gain modulation （XGM） effect of the semiconductor optical amplifier （SOA）. Moreover, the feasibility of this sys- tem is experimentally demonstrated by evaluating the impacts of the optical wavelength conversion, time domain waveforms, eye diagrams and bit-error-rate （BER） in AOWC. The results show that the proposal will be a promising solution for the next generation access networks.

AON中基于网络编码的单链路故障定位机制

文章提出了一种AON(全光网络)中基于网络编码理论的单链路故障定位机制。利用网络编码在信息处理和融合上的优势,可使从单个信源发出的信息经过不同的探测通路后得到不同的处理。若经过每条链路的探测通路的集合互不相同,则可以根据目的节点接收到的探测信息定位故障链路。仿真结果表明,该机制能够在保证定位准确性的同时有效地降低故障定位的开销。

基于AON+SDN技术构建智慧医院以太全光网络的实践与思考

概述了医疗行业传统网络环境的现存问题,阐述了智慧医院全光网络构建的技术路线,结合具体医院实例,探索了以AON+SDN技术为基础的医院网络环境的构建,助力智慧医院建设。

Wavelength Routing Algorithmof All Optical Network Based on Traffic Engineering

General multi-protocol label switching(GMPLS) based on traffic engineering is one of the possible methods to implement all-optical network. This method implements the network with IP technique and guarantees the quality of service with traffic engineering. Based on the establishment of selecting schemes of optical path and methods of traffic calculation, the wavelength routing algorithm of all-optical network based on traffic engineering is presented by combining with prior route of shortest path and traffic engineering, the algorithm procedures are given, and the actual examples are introduced as well as the analysis on simulation calculation. This research results have certain significance for the achievement of optical switching technique of all-optical network.

A novel data channel fault detection mechanism in optical burst switching networks

Fault detection in optical burst switching （OBS） networks will be a challenging task in the future. A novel mechanism based on probe burst （PB） and a new key concept is proposed to detect faults of OBS networks by sampling the health of data channels, which solve the difficulty of optical monitoring schemes while keeps the transparency of data network to Internet protocol （IP） packets. It takes full advantage of the characteristics of OBS, including architecture and signalling scheme, and introduces the excellent performances of single-hop-test used in electrical communication networks into OBS environment while avoids the shortcoming that any optical burst must undergo an optical-electric-optical （OEO） conversion. Well designed PB can provide exact criterion for judging whether protection/restoration should be excuted according to hard or soft fault identification.

A Novel Optical Control Plane for Switching an Electro-Optical Hybrid Node in Translucent WDM Optical Networks

In a translucent network scenario, development of an optical control plane (OCP) that is aware of the location and number of available regenerators and all-optical wavelength converters (AOWCs) is of paramount importance. However, current generalized multiprotocol label switching (GMPLS) protocol suite does not consider the distribution of regenerator and AOWC availability information to all the network nodes. In this paper, we propose a novel optical control plane (OCP) architecture that 1) disseminates information about network components (i.e. regenerators and AOWCs) to all the network nodes, and 2) evaluates candidate routes which use fewest amounts of network components. Performance of the proposed OCP is compared with a recently proposed hybrid OCP approach in terms of blocking performance, number of deployed components and lightpath establishment setup times. The obtained simulation results show that the proposed OCP approach demonstrates low connection blocking and establishes lightpaths by 1) minimizing the overall network cost owing to the deployment of minimum total number of network components, and 2) demonstrating acceptable lightpath establishment setup times at all traffic loads. Further, the proposed OCP methodology is compatible and suitable for controlling the operations of a novel electro-optical hybrid translucent node which is a latency efficient technology capable of delivering a cost effective implementation suitable for large scale deployment.

Computation at the speed of light:metamaterials for all-optical calculations and neural networks

The explosion in the amount of information that is being processed is prompting the need for new computing systems beyond existing electronic computers.Photonic computing is emerging as an attractive alternative due to performing calculations at the speed of light,the change for massive parallelism,and also extremely low energy consumption.We review the physical implementation of basic optical calculations,such as differentiation and integration,using metamaterials,and introduce the realization of all-optical artificial neural networks.We start with concise introductions of the mathematical principles behind such optical computation methods and present the advantages,current problems that need to be overcome,and the potential future directions in the field.We expect that our review will be useful for both novice and experienced researchers in the field of all-optical computing platforms using metamaterials.

Minimum coding nodes multicast tree for two-channel all-optical network coding scheme

A heuristic algorithm of establishing a minimum coding nodes multicast tree on which a two-channel all-optical network coding scheme can be performed is presented. To minimize the coding nodes, the heuristic graph-search control strategies are investigated. Firstly, a minimum relatedness principle is proposed to balance and minimize the out-degrees of the conventionally directed multicast tree. Secondly, a set of rules about bottom-up path search are presented to recover another path in the conventionally directed multicast tree, and a conflict-backtracking principle is given to minimize the coding nodes in this process. To evaluate the algorithm, some results are given. The results indicate that the algorithm can perform the expected function. Moreover, to further test and verify the algorithm, performances of different multicast modes are compared and analyzed. The results show that the multicast performances will be impaired if a multicast tree contains redundant coding nodes.

Design of a node architecture for logic-calculation Nased all-optical network coding scheme

Network coding brings many benefits for multicast networks. It is necessary to introduce network coding into optical networks. Nevertheless, the traditional network coding scheme is hard to be implemented in optical networks because of the weak operation capability in photonic domain. In the paper, we focused on realizing two-channel network coding in all-optical multicast networks. An optical network coding scheme which can be realized via logic shift and logic XOR operations in photonic domain was proposed. Moreover, to perform the network coding scheme the coding node structure was designed and the operation principle and processes were illustrated in detail. In the end of the paper, the performance and the cost of different all-optical multicast mode were compared and analyzed.

Network coding based all-optical multicast in WDM networks

Wavelength division multiplexing （WDM） has been becoming a promising solution to meet the rapidly growing demands on bandwidth. Multicast in WDM networks by employing free wavelength is an efficient approach to saving bandwidth and cost. However, the free wavelength may not identical between different hops in a multicast light-path, particularly in heavy load optical WDM networks. In order to implement multicast applications efficiently, a network coding （NC） technique was introduced into all-optical WDM multicast networks to solve wavelength collision problem between the multicast request and the unicast request. Compared with the wavelength conversion based optical multicast, the network coding based optical multicast can achieve better multicast performance with paying lower cost.

Application of Automatic Chromatic Dispersion Compensation for Realization of All-Optical Network

We have studied the algorithm for the automatic chromatic dispersion compensation using bit error rate (BER) and Q-factor optimization for realization of dynamically reconfigurable all-optical .network. We have made sure good performance using the compensation system by laboratory experiments.

光接入网技术研究

文章介绍了宽带光纤接入网系统和其中的几种主流接入方式,并详细比较了几种接入技术在应用上的优缺点,最后给出了建议和展望.

全光网络管理信息传输研究

文章介绍了采用波分复用技术传输和波长路由的全光网络，然后针对它的管理特征提出了三种网管信息传输模式：寄生传输、 OSC传输和光树传输；最后论述了光树传输将成为光网的一个技术发展趋势。

全光网络中的光开关技术及应用

在整个光通信系统中,光开关是较为重要的光无源器件,在光网络系统中可对光信号进行选择性操作。光开关的研究日益成为全光通信领域关注的焦点。总结了光开关在全光网络中的应用,介绍了光开关的基本工作原理及光开关技术的进展。

全光通信网络节点功能结构研究

密集波分复用 (DWDM )技术在提高传输能力的同时 ,还具有无可比拟的联网优势。使用光滤波器件或光开关就可构成重构性的具有联网功能的光分插复用器(OADM )。OADM和DWDM技术的结合构成了最佳的全光城域网解决方案。本文描述了全光通信网络节点功能结构 ,研究了以光转发器OUT和OADM为基础的各种全光网节点结构。

全光网络的安全性探讨

全光网络通过波长路由为用户提供一个透明的光路,因此带来了许多安全性问题。袭击者往往根据全光网的弱点进行业务干扰和分光窃取信号。文章主要探讨了与全光网络的光层有关的安全管理问题。在对全光网络的安全特征进行分析的基础上,介绍了全光网可能遭到的恶意攻击的3种方式。针对不同的攻击方式提出了一些解决办法,并对这些方法的优缺点作了分析比较。

三网融合时代广电光传输网络发展趋势分析

在三网融合的趋势下,广电业务正在从传统的广播电视业务向多业务方向发展,广电运营商为了满足日益增长的数字业务需求而不断地升级其干线传输网络,通过比较SDH,MSTP,WDM,OTN和AON等光传输网络技术特点,分析广电光传输网络的发展趋势以及适合广电运营商各自特点的光传输网络技术。