Optical Communications Research Activities at COM RD1 Siemens S.A.

This article summarizes the research activities carried out by the R&D Optical Networks Communications group (COM RD1), at Siemens S.A., in collaboration with both universities and other research institutes. These activities cover various aspects of advanced modulation formats, all optical wavelength conversion, optical quality of signal monitoring in transparent WDM networks, routing, and wavelength assignment in optical networks.     

Optical Communications Research Activities at COM RD1 Siemens S.A.

Abstract

This article summarizes the research activities carried out by the R&D Optical Networks Communications group (COM RD1), at Siemens S.A., in collaboration with both universities and other research institutes. These activities cover various aspects of advanced modulation formats, all optical wavelength conversion, optical quality of signal monitoring in transparent WDM networks, routing, and wavelength assignment in optical networks.     

光纤通信的过去、现在和未来

简略介绍了世界光纤通信发展历史,概括了光纤通信的现状,最后重点介绍了中国光纤通信的发展历程。     

Selection of Acquisition Scan Methods in Intersatellite Optical Communications

In this paper, a theoretical model of the acquisition in intersatellite optical communications (IOC) is founded with the assumption that beacon pointing errors could be modeled as Gaussian random variables. An optimal scan method should be chosen according to the average acquisition time under a certain acquisition probability. With analysis of the most common scan methods during the establishment of IOC, the raster-spiral scanning can substitute the spiral scanning is found. The raster scanning and raster-spiral scanning are simulated using Monte Carlo method and the result shows the first one is optimal for acquisition in IOC.     

Ultra-High-Capacity Passive Optical Network Systems with Free-Space Optical Communications

Abstract

This article experimentally demonstrates a hybrid fiber–free-space passive optical network that enables high spectral density, aggregated capacity, and total throughput through ultra-dense wavelength-division multiplexing baseband and radio-over-fiber channels. Ultra-dense wavelength-division multiplexing 10-Gb/s Nyquist-shaped 16-ary quadrature amplitude modulation, 10-Gb/s radio-over-fiber orthogonal frequency-division multiplexing, and 8.75-Gb/s baseband orthogonal frequency-division multiplexing signals per user were transmitted through a maximum 40-km passive optical network, which includes a 6-m free-space optics link with acceptable performance.     

Selection of Acquisition Scan Methods in Intersatellite Optical Communications

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空间激光通信组网光学原理研究

随着高分辨率观测技术的发展和高数据率信息传输的迫切需求,研究高速率激光通信的组网技术迫在眉睫。分析了空间激光通信链路组网所需要满足的基本要求及其实现中必须解决的技术难点,提出了组网光学原理,同时研究了一种可用于多目标间同时进行激光通信的技术方案,设计了以旋转抛物面为基底的多反射镜拼接结构的光学天线、中继光学系统以及发射接收与捕获、跟踪和对准(APT)系统,为空间激光通信链路组网提供了新的技术途径。     

一种适用于光突发交换网络的背景流量估计模型

平面背景流量的强度是光突发交换网络中的一个重要参数。该参数直接影响网络的性能并约束网络边缘节点的组装算法。指出了在配置波长转换器的情况下,核心节点控制平面的服务速率是与背景流量密切相关的随机变量而不是确定性变量。构建了M/D/1和一种特殊的M/G/1排队模型分别描述不同配置的核心节点的行为,并以剩余偏置时间为观测变量,构建了核心节点的背景流量估计模型。仿真和数值分析表明,该模型能够实时反映出核心节点控制平面的背景流量强度。     

Polarization conversion at the discontinuities in semiconductor opto-electronic systems

The origin of unexpected polarization conversion at the junctions between two semiconductor rib waveguides is demonstrated by using full-vectorial numerical approaches.     

基于异步延迟采样的光通信性能监测方法

基于异步延迟采样和人工神经网络统计学习提出了一种光通信性能监测方法。通过对高速光信号进行异步延迟采样,获得信号二维幅度直方图,然后提取其中特征参数并对人工神经网络进行训练,最后以人工神经网络的预测输出实现对光信号损伤的监测。构建10 Gb/s非归零码开关键控,40 Gb/s光学双二进制码和归零码差分移相键控光通信仿真系统,并对光信噪比、色散和偏振模色散损伤进行监测。仿真结果表明,所提方法对被监测光信号的速率、码型调制格式透明,可同时准确监测多种并存的传输损伤,损伤参数监测误差小于5%。该方法具有电域处理带宽要求低、采样机制简单的特点,适用于分布式在线光性能监测。     

相移干涉计量中相移器的原路相干相位检测标定

A new all-optical clock extraction scheme based on an asymmetric nonlinear optical loop mirror (NOLM) is proposed and demonstrated experimentally. The proposed scheme can operate at a relatively low switching power (only 0.3 Pπ is required for the clock pulse, where Pπ means the required switching power for the maximum switching in the asymmetric NOLM) and a relatively low input clock to data ratio (2～2.5). The proposed scheme is promising for clock extraction in the future ultrahigh-speed self-clocked OTDM network.     

Applications of Nonlinear Effects in Highly Nonlinear Photonic Crystal Fiber to Optical Communications

Unique dispersion characteristics and enhanced nonlinearity make the small-core photonic crystal fiber (PCF) an ideal candidate for nonlinear optical devices to telecommunication applications. Some technical reasons behind great research interest of highly nonlinear PCFs in optical communication components are reviewed. Nonlinear effects in highly nonlinear PCFs and their research progress are presented. Several typical applications including WDM sources, optical amplification, optical switching, wavelength conversion, optical regeneration and all-optical demultiplexing etc are introduced, together with state-of-the art performances. Some new possible applications and future prospects are discussed.     

Fiber-Optical Parametric Amplification of Sub-Picosecond Pulses for High-Speed Optical Communications

Abstract

This article reviews recent results of amplification of short optical pulses using fiber-optical parametric amplifiers. This includes chirped-pulse amplification of 400 fs pulses, error-free amplification of a 640-Gbit/s optical time-division multiplexed signal with less than a 1-dB power penalty, and all-optical phase-preserving amplitude regeneration of a 640-Gbit/s return-to-zero differential phase-shift keying optical time-division multiplexed signal.     

Optical wireless sensor networks using tunable optical filters

A novel decision gathering scheme for optical wireless sensor networks (OWSNs) is proposed and thoroughly analyzed in this article. The proposed technique relies on a tunable optical filter (TOF) that is mounted on each sensor node. Specifically, the received laser signal from a central unit at any particular node is modulated through the TOF, where it is either rejected or passed in accordance to the sensed result. The output of the TOF is passed to a corner cube reflector (CCR) that reflects the optical signal either back to the central unit or to another node in the OWSN. Three different setups are considered to implement the proposed scheme and the pros and cons of each setup are thoroughly discussed. It is revealed that the energy requirement of each sensor node is minimized as energy is only consumed in the process of sensing and adjusting the TOF. The performance of the proposed scheme is analyzed through a mathematical framework to derive the average decision error rate (DER) for all setups. Moreover, simulation results analyze the impact of key system parameters including atmospheric turbulence, transmit power, link distance, filter efficiency and detection threshold.     

Asymmetric Nonlinear Optical Loop Mirror for All Optical Clock Extraction in Self-clocked Optical Transparent OTDM Network

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信号与本振光振幅分布对星间相干光通信系统混频效率的影响

星间相干光通信系统中,信号光与本振光的不同分布将影响外差混频效率.在假设信号光与本振光偏振一致、相位匹配、几何中心重合的前提下,详细推导了信号光振幅为平面波(Uniform)、高斯(Gauss)分布,本振光为艾里斑(Airy)、Uniform及Gauss分布时的6种外差混频效率关系式,其中4种得到了精确的解析式.在此基...     

像差对星间相干光通信接收系统误码性能的影响

以空间链路方程为基础,详细推导了具有不同像差时的星间相干光通信接收系统信噪比表达式。以通信距离为60000km、速率为2Gb/s的2PSK零差同步轨道接收系统为例,通过数值仿真,全面比较了接收天线的倾斜、离焦、彗差和像散等像差对接收系统误码率(εBER)的影响。结果表明,不同像差单独作用时,倾斜像差的影响最大,象散的影响最小;不同像差相互作用时,它们中的某些能部分实现相互校正,从而降低误码率。以εBER≤10-6为比较标准,当彗差W31/λ≤1.00时,调整倾斜像差能实现它们之间的部分校正;当像散W22/λ≤0.53时,调整离焦能对像散进行部分校正。因此,在设计接收系统时,接收天线的像差所产生的影响不容忽视。这将为设计星间相干通信接收系统提供必要的理论依据。     

位错型微机械可变光衰减器的研究

介绍了一种基于微机械技术实现的可变光衰减器,通过微电磁驱动器改变输入输出光纤之间的径向偏移量来调整衰减量。基于波导传输理论分析确定了器件的结构参量,并通过集成电路微细加工工艺实现了器件的制作和封装。测试结果表明,该可变光衰减器的插入损耗小于1dB,动态范围约35dB,工作电压小于5V,偏振相关损耗小于0.1dB,体积为20mm×15mm×8mm,有望为全光网提供一种低成本,高性能的光通信器件。     

Bit Constraints Analysis of Multihop All-Optical Networks with Deflection Routing

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