基于表面等离子激元的自由空间广角接收机研究

Wide field-of-view （FOV） free-space receivers are promising for optical wireless communications, which can reduce the requirements on aiming and tracking. However, the FOV is limited by some tradeoffs of the receiver＇s components employing conventional optical devices. In this paper, we proposed a wide FOV optical receiver based on the extraordinary optical transmission mechanism of surface plasmons on a dielectricmetal interface. The proposed receiver has a flat response over a relative wide range of incidence angles. Moreover, the received optical energy density has been enhanced greatly compared to the incidence. Related mechanisms as well as the optimization method are investigated. Potential applications are also discussed.     

Message from the Guest Editor for the Special Issue

The communications industry and research have been developed greatly since optical fiber communications technologies became practical. More than 80 percent of the traffic of today＇s communications network, which increases at the speed more than Moore＇s law attributed to the rapidly growing network users and services, is carried by optical fiber networks. Optical fiber communications networks will play an essential role in the development of information society in the future for its large capacity, high bit rate, low energy consumption and low cost. Moreover, the business Terabit/s transsport systems and Petabit/s switching nodes must be implemented by optical communications technologies. In a word, optical fiber communications technologies will be the key part of next generation network in China.     

Parallel link server architecture: a novel contention avoidance mechanism in OBS networks

Optical burst switching (OBS) is thought to be the best way to adapt bursty traffic of IP-based next generation network services. However, there are a lot of challenges to make OBS networking a reality. Of most concern is burst contention avoidance. The major contention avoidance resolutions in literature are wavelength conversion, fiber delay lines, and deflecting routing. They are very vulnerable to network load and may suffer from severe data loss in case of heavy traffic. Even at moderate traffic, contention caused by using these methods lead to burst blocking and data losses. In this article, a novel contention avoidance technique is presented by using the parallel link server (PLS) architecture, which may overcome the lack of information at the edge node and the absence of global coordination among nodes. Using Poisson and Self-Similar traffic arrival models, the proposed mechanism is compared with the traditional single link server architecture through simulation in the 14-node national science foundation network. The numerical results show that this architecture, without additional other methods, can obtain burst blocking and data dropping probabilities with almost two orders of magnitudes less than those in the single link server architecture. Gains are achieved by less than 7% increase in end-to-end delay when carrying coordinated traffic and a load under 0.45.     

光分组交换网

本文介绍了全光分组交换网的国内外研究状况，讨论了光分组交换节点的功能和结构及其实现光分组交换网的关键技术，对光分组交换网的研究具有重要的参考价值。     

一种新的为实现IP Over WDM设计的光波长路由器

将IP与WDM相结合是一个极具吸引力的研究方向。与以往点到点的方式不同,提出了一种新的实现IP over WDM的方案,称为DPDP（缺省波长和专用波长,default path and dedicated path）,给出了详细的节点结构图,并解释了其工作流程。最后对相关问题进行了讨论。     

4×2.5Gbit/s,154km无中继波分复用系统现场试验

两套供工程使用的４×２，５Ｇｂｉｔ／ｓ、１５４ｋｍ无中继波分复用光纤通信系统第一次在国内研制成功。该系统采用了波长控制器和波长转发器。系统可长期稳定工作并可接入任何厂家任何机型的２．５Ｇｂｉｔ／ｓ光端机。经过广东省邮电管理局组织的严格测试，二系统共８信道均２４小时无误码。并通过了由国家经贸委、电子工业部委托国家教委组织的专家鉴定。     

An improved theory of microwave open resonators

The analytic theory of microwave open resonators is improved here by means of solving the complex Airy equation, that the Q-value as well as the argument of field profile may be given accurately. The resonance conditions for open cavities with high and moderate Q-values are derived analytically. Theoreticl Q-values are well agreed with the measured ones from experiments.     

10频道“波分复用＋光纤放大器”全光通信实验系统

在国内首次研制了使用１个光纤放大器的１０频道１０２ｋｍ无再生中继“ＷＤＭ＋ＥＤＦＡ”全光光纤传输实验系统。每频道传输码率为１４０Ｍｂ／ｓ或２８０Ｍｂ／ｓＮＲＺ。所用光纤放大器为增益平坦型，小信号增益为３５ｄＢ。系统全部采用国产ＤＦＢ激光器，各频道波长分别为１５３１、１５３５、１５３７、１５４５、１５４７、１５４９、１５５１、１５５９、１５６１ｎｍ，在波长为１５５１ｎｍ的频道内布置了２路频分复用（ＦＤＭ）系统。波长分布遍及整个光纤放大器的通带。经无再生中继传输１０２ｋｍ后，在误码率为１×１０￣（－９）条件下，实测了尚有数ｄＢ以上（最大为１２ｄ８）的功率裕量。系统使用光栅合、分波器作为波分复用和解复用器，频道间隔为２ｎｍ及其整数倍，系统具有１８个频道的能力。     

短期负荷预测相关因素的自适应训练

提高预测精度是短期负荷预测的基本目标。目前已提出了处理相关因素的规范策略和短期负荷预测的综合模型。在此基础上，将自适应训练的思想引入到短期负荷预测相关因素处理中，提出了相关因素自适应训练的若干概念，并分析了自适应训练中的基本问题，给出了短期负荷预测过程的抽象化模型，提出了两种训练负荷相关因素的算法：摄动算法和遗传算法，最后比较了这两种算法的优缺点。算例分析表明，通过自适应训练相关因素，实际预测的效果得到显著改善。     

光学阿达玛编码技术原理的一种新描述

在Hadamard Transform Optics一书中,Harwit M.对光学阿达玛编码理论作了总结。本文利用矩阵和统计学描述了光学阿达玛编码技术的基本原理。这种描述方法具有简明、条理、逻辑性强的特点。