On polarization sensitivity of all-optical label swapping using synchronous phase modulation

Polarization sensitivity degrades the performance of many optical devices in optical packet switched networks. We investigate the polarization sensitivity for all-optical label swapping for the first time. We propose and demonstrate a polarization-insensitive phase modulator for all-optical label swapping. The polarization sensitivity of the power penalty for the label swapping is less than 0.3 dB.     

Performance of All-Optical Multicasting Via Dual-Stage XGM in SOA for Grid Networking

The letter presents a study on the performance of an all-optical multicasting technique utilizing the nonlinearity of semiconductor optical amplifier (SOA) technology for all-optical grid computing network. The technique not only has the capability to optically control the degree of multicasting but also performs all-optical switching simultaneously. Experimental results show the design's capability to multicast an incoming 10-Gb/s optical signal onto 16 outgoing signals using cross-gain modulation in a single SOA. A second SOA is also included in the design as a 2R regenerator     

空间激光通信网络中的全光相位再生技术

围绕空间激光通信网络中高速数据多跳传输应用需求,针对相位调制激光链路经过空间长距离传输后信号质量劣化的问题,研究了基于相位敏感四波混频参量效应实现二进制相位调制高速激光信号的全光相位再生技术。利用Matlab软件数值分析了全光相位再生系统的影响因素,并基于OptiSystem仿真平台搭建了全光相位再生系统。结合高轨-地面站空间激光通信系统链路预算,对速率为10 Gbit/s的DPSK信号光经背靠背、相位噪声劣化以及劣化后全光相位再生处理三种传输场景进了对比分析。模拟仿真结果与数值分析结果均表明,与劣化后未经再生处理的系统相比,全光相位再生处理后的系统误码率平均优化4个数量级,信噪比提升约3 dB,表明该空间激光通信全光相位再生技术可实现相位调制信号的全光相位再生,能够有效提升空间相干激光通信系统的性能,可以应用于空间高速激光通信网络中继节点处的全光数据中继等方向。     

All-optical signal processing in ultrahigh-speed opticaltransmission

The coming broadband era will require very high-speed technologies that can handle more than 100-Gb/s for both transmission lines and transmission nodes. Novel all-optical signal processing technologies that offer unsurpassed performance are urgently required. This article briefly reviews the essential photonic technologies required for high-speed optical TDM transmission, including ultrashort optical pulse generation, all-optical multiplexing/demultiplexing, and optical timing extraction techniques. Recent all-optical TDM transmission experiments up to 100 Gb/s are introduced together with major issues and future prospects     

Device Design and Characteristics for SOA—based All Optical Signal 2R Regeneration

A new scheme based on SOA-MZI for all-optical 2R regeneration is proposed.The characteristics of gain and switching window of this device are investigated in detail.Numerical simulation results indicate that the nonlinear gain compression,the time delay between the input optical signal and the width of the optcial pulse are essential parameters for a good performance of all-optical 2R regeneration.     

Analytical study of crosstalk propagation in all-optical networks using perturbation theory

The performance of current optical networks is inherently limited by the speed of electronic components and, in particular, by electronic switches. A new generation of optical networks, referred to as all-optical networks, overcomes this limitation by switching data entirely optically using all-optical crossconnects (OXCs). However, all-optical networks are prone to phenomena that are unknown to current optical networks with electrical regeneration: OXCs are subject to optical leaks, called crosstalk, resulting in unwanted components being added to transmitted signals, and this crosstalk is transmitted over very long paths without any signal regeneration. In this paper, we consider the interplay between fiber nonlinearity and crosstalk signals over long distances as the source of performance degradation, measured in terms of Q factor. We present an analytical crosstalk model for all-optical networks and give expressions for the performance degradation resulting from the joint propagation of a signal [using a continuous-wave (CW) assumption and perturbation theory] and crosstalk in large networks. Analytical calculations required by this model are shown to be much less computationally intensive than simulations. Simulations are carried out to validate our analytical model and good agreement is found between the analytical model and simulations for wide ranges of parameters.     

All-Optical Byte Recognition for 40-Gb/s Phase-Shift-Keyed Transmission Using a Planar-Lightwave-Circuit Passive Correlator

We demonstrate all-optical recognition of a byte pattern embedded in phase-shift-keyed data streaming at 40 Gb/s. We use matched filtering to generate an autocorrelation pulse indicating the pattern matching. Matched filtering is implemented using a reconfigurable silica planar-lightwave-circuit optical delay-line filter. We show excellent discrimination against spurious patterns consistent with the theoretical predictions.     

A novel all-optical label swapping based on RZ-DQPSK/IRZ-ASK combined modulation format

A novel all-optical label swapping based on optical return zero (RZ) differential quadrature phase shifted keying/inverse return zero amplitude shifted keying (RZ-DQPSK/IRZ-ASK) combined modulation format scheme is investigated and analyzed theoretically. Internet protocol (IP) packets can be efficiently labeled and processed using this proposed scheme. Numerical simulation is taken to demonstrate the transmission characteristic of the all-optical label swapping based on RZ-DQPSK/IRZ-ASK modulation format. The transmission performance can be affected by the duty cycle of the IRZ pulse, the IRZ-ASK label extinction ratio, the dispersion compensation ratio, received optical power and the coupling coefficient of the coupler. Results show that the IRZ-ASK label extinction ratio is almost infinite and preferable performance is obtained. The proposed scheme is a practical solution to meet the data rate and cost-efficient of the optical links simultaneously in tomorrow's all-optical label swapping.     

动态业务条件下多粒度全光网性能分析与研究

多粒度交换技术利用波带级路由以及光纤级路由,可有效降低光交叉连接器的复杂度。但多粒度交换增加了光网络的逻辑层次结构,使得网络中的路由与资源分配问题更为复杂,多粒度全光网中的多层联合路由机制是影响网络性能的关键。本文对动态业务下多粒度全光网中的资源分配策略进行了深入研究,比较了采用不同节点交换比例时网络的阻塞性能,分析了不同业务量时多粒度交叉连接节点的最佳波带粒度,并结合经济性对多粒度全光网的性能进行了综合分析。     

光网络中的全光再生

在超高速大容量光网络中,全光3R再生（再定时、再整形、再放大）是非常必要的。光判决门是全光3R再生中非常重要的部分,其开关特性是影响全光3R再生的重要因素。在阐述了光判决门的研究现状的基础上,重点评价了以非线性光开关为基础的光判决门的开关特性及其串话、消光比、抖动容限等,以对全光3R再生的研究和优化设计提供依据。     

全光网中光码流性能的整体监控

波分复用(WDM)多粒度交换可重构全光网是当前光通信网发展的方向,该文构造了一种实际试验网,提出了一种 眼图法对网中数字光信号进行全面监控的方法,并在自建WDM多粒度交换可重构全光网试验床上进行了演示,结果显示在网络重构等各种条件下均可对网中各波长通道数字信号的信噪比、定时抖动、功率、误码率等进行实时监测控制,该方法对光信号的协议和速率透明且能对各种光性能劣化进行鉴别。     

Optical CDMA for All-Optical Sub-Wavelength Switching in Core GMPLS Networks

Generalized multi-protocol label switching (GMPLS) is a multipurpose control-plane paradigm that extends the MPLS scheme allowing switching without recognizing packet boundaries. In this paper, we present a novel extension that exploits a new physical layer for switching in optical GMPLS. The proposed extension is achieved through adding an optical code switching layer, or code switch capable (CSC) layer, to the existing label mapping layers. Our proposal enables finer granularity at sub-wavelength level in all-optical GMPLS core switches, resulting in significant enhancements to traffic isolation capabilities for all-optical GMPLS core switches. We employ mathematical analysis to derive performance bounds for the proposed scheme, from both the labeling capacity and network throughput points of view. We use our analytical model to derive several optimum operating points for the network, and show that our techniques significantly improve the overall performance of all-optical core networks     

Ultrashort Optical Pulse Detection for High-Speed Asynchronous Optical CDMA Networks

Like its wireless counterpart, optical code-division multiple access (optical CDMA) offers greater scalability than other optical multiplexing schemes and provides flexible quality of service, physical layer privacy and asynchronous access . However, unlike wireless CDMA, high bit-rate optical CDMA networks use much higher bandwidth, which cannot be effectively processed with modern electronics rendering many earlier developed detection schemes inapplicable. In this paper we show both theoretically and experimentally that conventional electronics-based detection is inefficient in optical CDMA networks and limits the total network throughput by the bandwidth of the photodetector used. As a solution, we show that network performance can be greatly improved using ultrafast all-optical signal processing for signal detection. Recently developed all-optical thresholding devices performing cubic transformation allow for more than seven times increase in throughput for typical network parameters. A comprehensive comparison of different detection methods for optical CDMA including optimized electronics-based and all-optical signal processing-based is given for the first time.      

All-optical analog-to-digital converters, hardlimiters, and logicgates

The authors propose and analyze the optical signal processing functionality of periodic structures consisting of alternating layers of materials possessing different Kerr nonlinearities. They explore structure-materials-performance relationships in all-optical analog-to-digital converters, hardlimiters, and AND and OR gates. They show that their proposed analog-to-digital converters can extract a binary word from multilevel optical signals in a single bit interval. They also propose a family of optical limiters whose output signal clamps to a set upper logic level for any input value exceeding a chosen threshold. They explore the performance of an all-optical logic gate whose forward-directed output implements a binary AND and whose backward-directed output implements an OR function     

Field Trial of All-Optical Networking Controlled by Intelligent Control Plane With Assistance of Optical Performance Monitors

A field trial of all-optical networking by an intelligent control plane based on generalized multiprotocol label switching (GMPLS) technologies was successfully conducted with the assistance of optical performance monitors (OPMs) capable of monitoring the in-band optical signal-to-noise ratio (OSNR). In the field trial, the GMPLS control plane was applied to not only fast provisioning of all-optical paths but also to end-to-end restoration of optical paths triggered by OPMs. Reliable and stable network operation was achieved as a result of applying the GMPLS control plane and OPMs.      

基于PPLN波导的全光4线-2线优先编码器

全光网要在光域上实现信息的传输以及路由的交 换,需要依靠全光逻辑器件来完成。但是由于已实 现的全光逻辑器件功能较为单一,使得全光分组交换技术无法达到实用阶段。为开拓新的全 光逻辑运算功 能,在PPLN波导的和频+差频效应(SFG+DFG)基础上,提出了全光4线-2线优先编码器设计 方案。首 先根据PPLN波导的全光逻辑运算原理,分析4线-2线优先编码器的逻辑表达式,然后利用一 个PPLN波 导实现4线-2线优先编码器的高位输出,利用两个PPLN波导级联实现4线-2线优先编码器的 低位输出。 通过数值仿真得到信号波形和眼图,计算了消光比、脉冲宽度、半高全宽和峰值功率延迟时 间,分析结果 表明,本方案能在光域实现4线-2线优 先编码器的逻辑功能,且输出信号质量较好,扩展了 PPLN波导在全光逻辑信号处理方面的能力。     

Analysis of optical amplifier noise in coherent opticalcommunication systems with optical image rejection receivers

A detailed theoretical analysis of optical amplifier noise in coherent optical communication systems with heterodyne receivers is presented. The analysis quantifies in particular how optical image rejection receiver configurations reduce the influence of optical amplifier noise on system performance. Two types of optical image rejection receivers are investigated: a novel, all-optical configuration and the conventional, microwave-based configuration. The analysis shows that local oscillator-spontaneous emission beat noise (LO-SP), signal-spontaneous emission beat noise (S-SP), and spontaneous-spontaneous beat noise (SP-SP) can all be reduced by 3 dB, thereby doubling the dynamic range of the optical amplifier. A 2.5-dB improvement in dynamic range has been demonstrated experimentally with the all-optical image rejection configuration. The implications of the increased dynamic range thus obtained are also discussed from a systems point of view     

All-optical logic NXOR based on semiconductor optical amplifiers with the effect of amplified spontaneous emission

The performance of all-optical logic NXOR gate based on semiconductor optical amplifiers Mach-Zehnder interferometer(SOAs-MZI)is simulated.The effects of amplified spontaneous emission(ASE)and the input pulse energy on the system’s quality factor are studied.For the parameters used,the all-optical logic gates using SOAs are capable of operating at speed of 80Gbit/s.     

All-Optical Switches in Optical Time-Division Multiplexing Technology: Theory, Experience and Application

All-Optical Switches in Optical Time-Division Multiplexing Technology: Theory, Experience and Application     

Shared-by-wavelength-switches: a node architecture using small optical switches and shared wavelength converters

Wavelength converters can significantly improve the blocking performance of all-optical networks. The existing node architectures require large optical switches for sharing the wavelength converters. This letter proposes a new node architecture called shared-by-wavelength-switches . This node architecture requires significantly smaller and cheaper optical switches for sharing the wavelength converters while it gives nearly the same blocking performance as the existing node architectures.