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1.
充分抽复用(OADM)是实现全光网络(AON)的关键技术,介绍了OADM的4种方案,重点对基于声-光可调谐波波器(AOTF)的OADM进行研究,认为随着器件性能的不断改善,AOTF将在全光网络建设中起到重要作用。  相似文献   

2.
光分插复用 (OADM)是实现全光网络 (AON)的关键技术 ,介绍了 OADM的 4种方案 ,重点对基于声 -光可调谐波波器 (AOTF)的 OADM进行研究 ,认为随着器件性能的不断改善 ,AOTF将在全光网络建设中起到重要作用  相似文献   

3.
光分插复用(OADM)是实现金光网络(AON)的关键技术,介绍了OADM的4种方案,重点对基于声-光可调谐波器(APTF)的OADM进行研究,认为随着器件性能的不断改善,AOTF将在全光网络建设中起到重要作用.  相似文献   

4.
全光通信网中的光分/插复用器   总被引:1,自引:0,他引:1  
在对现有的各类光分/插复用器(OADM)进行总结和比较的基础上,按结构特点将其归纳为5类基本形式,即分波器 波长交换单元 合波器型,波长光栅路由器(WGR)型,声光可调谐滤波器(AOTF)型,解复用器/复用器型和耦合单元 滤波单元 合波器型。论述了各类OADM的工作原理、结构、性能特点、技术水平及相应的关键技术,为发展相关技术、开发OADM产品、设计具有分/插复用功能的波分复用系统提供了依据和参考。  相似文献   

5.
#光突发交换(OBS)网络的数据信道由于采用统计复用的全光透明传输方式,因此其性能监视和故障发现 是一项极具挑战性的研究课题。在分析使用平均功率监测方法检测(OBS)网络故障时存在缺陷的基础上,提出了 基于瞬时光功率监测的光突发交换故障发现机制,该机制采用瞬时光功率监测与告警过滤相结合实时监视信道, 有效过滤误告警和冗余告警,为故障定位模块提供更准确的告警信息;理论分析和仿真结果表明;在(OBS)网络 中,基于瞬时功率监测的告警过滤机制具有更强的性能监视和故障发现能力。  相似文献   

6.
全光网络中的光开关技术及应用   总被引:1,自引:0,他引:1       下载免费PDF全文
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。  相似文献   

7.
采用码分复用(OCDM)与波分复用(WDM)相结合的技术可以构成多跳网,其关键技术是波长和地址码的转换,但转换中存在着电子瓶颈.提出了一个全光的地址码转换方案,该方案依赖于光硬限幅器技术,适用于时域编码的OCDM系统.分析了影响该方案工作性能的各项因素,并利用Gaussian近似,得到了码字转换差错率的边界与光硬限幅器的阈值之间的关系,以及该光码字转换方案对网络端到端误码率性能的影响.  相似文献   

8.
提出了一种大容量的WDM光时分复用网络的概念。这种网络既可利用WDM技术中的波长选路技术,又对每个波长独立进行光时分复用,大大提高了网络的传输速率。文中提出了在光网络中实现时分复用的方式和两种时隙交换的节点结构,分析了WDM光时分复用网络的容量及其优点.指出WDM时分复用是未来全光网络的发展方向。  相似文献   

9.
光标记交换(OLS:Optical Label switch)是一种新的光交换新技术,OLS是光包交换(OPS:Optical Packet Switch)的实现形式,90年代以来,OLS从器件、系统、网络诸方面正以惊人速度向前发展,并逐步向实用化迈进。提出了一种基于光标记交换技术的全光网络的新的设计方案,叙述了这种方案的设计原理和该网络的功能,给出了光标记交换全光网的拓扑结构和OLS节点的结构。  相似文献   

10.
采用统计方法研究了波分复用(WDM)光网络中网络拓扑对同频串扰积累的影响。网络拓扑用两个参数描述:网络中节点数和网络连接度。在WDM光网络中,同频串扰由光交叉连接节点/光上下路节点(OXC/OADM)中非理想的光开关和复用器/解复用器引入,是使信号质量恶化的主要原因之一。结果表明:对于给定的网络规模,存在一个最佳的网络连接度可使同频串扰的积累最小,从而降低对光器件的要求。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

15.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

16.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

17.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

18.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

19.
Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of  相似文献   

20.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

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