拉曼光纤放大器（FRA）和掺饵光纤放大器（EDFA）相结合构造宽带放大器

概述了拉曼光纤放大器（FRA）的掺饵光纤放大器（EDFA）的理论模型，据此计算它们的增益谱，重点阐述将FRA和EDFA相结合构造宽带放大器，利用遗传优化算法对增益谱进行均衡以实现宽带放大。     

光纤通信系统中的掺铒光纤放大器技术

掺铒光纤放大器(EDFA)的信号增益谱很宽,达125GHz或更高,可用于宽带通信,是全光通信网中的关键技术器件.本文介绍了掺铒光纤放大器在全光同络中发挥的作用,阐述了掺铒光纤放大器的特点和应用.着重分析了掺铒光纤放大器在全光通信系统中的工作原理.并对其发展前景作出了展望.     

掺铒光纤放大器放大特性分析

介绍了掺铒光纤放大器(EDFA)的基本工作原理,建立了放大特性理论模型。并在不同条件下模拟仿真了其增益特性。揭示了EDFA的增益特性与泵浦光功率、掺铒光纤长度(EDF)的关系。     

拉曼光纤放大器在DWDM中的应用

随着高密度波分复用(DWDM)技术的发展,拉曼光纤放大器以自身固有特性重新崛起.介绍了拉曼光纤放大器的基本原理,对比了拉曼光纤放大器和掺铒光纤放大器(EDFA)各自的特点,并讨论拉曼光纤放大器在DWDM中的应用.     

喇曼光纤放大器(RFA)的研究

光放大器在光通讯系统中具有重要作用。近几年来，人们一直致力于全光型中继器的研制，先后推出多种光放大器。将半导体光放大器(SOA)、掺铒光纤放大器(EDFA)与喇曼光纤放大器(RFA)主要特征及性能作出比较，并在此基础上，提出4种RFA的典型设计方案，进而得出“喇曼放大器宜采用分布式、反向泵浦以降低噪声，提高信噪比；若采用多波长泵浦，各波长间隔和输出功率的配置是关键所在”的结论。     

两端加入布拉格光纤光栅的掺铒光纤放大器瞬态分析

首先介绍了利用掺铒光纤放大器（EDFA）快速计算的理论模型分析一般EDFA瞬态响应中存在的增益饱和引发的串扰现象。然后分析了两端加入布拉格光纤光栅的EDFA,表明这种改进后的EDFA可以有效地抑制增益饱和引发的串扰现象,使EDFA更加适合应用于WDM光通信系统,有关的数值计算结果和实验相符。     

基于双折射光纤布拉格光栅的全光自动增益控制掺铒光纤放大器

报道了一种基于双折射光纤布拉格光栅(Hi-Bi FBG)的全光自动增益控制掺铒光纤放大器(EDFA).通过利用双折射光栅作为选频器件,在放大器中建立起了双波长的控制光.实验结果表明双波长控制光能够有效地钳制该放大器的增益.其在1545和1555 am处的增益被控制在±0.42和±0.52 dB范围内,同时对应的饱和输出功率分别达到了6.97和7.16 dBm.     

掺铒光纤放大器黑盒模型理论与实验

基于掺铒光纤放大器 (EDFA)两能级放大模型基础上推广了黑盒模型的应用范围 ,针对光放大器不同工作模式 ,给出了利用该模型计算多路波分复用 (WDM)输入光信号增益的方法 ,模拟计算了有 6路 WDM光信号输入时 ,经 EDFA放大后的光谱图 ,并与实验结果进行了比较 .结果表明两者十分吻合     

一些宽带光纤放大器的原理和结构

介绍了宽带光纤放大器的两种基本类型：现已应用于工程实践的宽带拉曼光纤放大器和前景看好的超宽带光譬苎奎器。誓分析了若干具体的宽带光纤放大器的结构和性能。指出了宽带光纤放大器的研究重点是分波段光纤放大器和宽带混合光纤放大器。     

光纤拉曼放大器的设计及实验研究

该文设计并实现了C+L波段的宽带光纤拉曼放大器.测试结果表明,在仅有3个泵源的条件下,实现了带宽大约57nm、开关增益平均为10.5dB的宽频带放大,并且本系统具有优良的增益平坦特性( ±0.4dB)和平均有效噪声系数(约-3.2dB).     

Markedness and its Interpretation in Language Use

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.     

Features of Women's language

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.     

低渗透非均质砂岩油藏启动压力梯度研究

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。     

On Tragic Consciousness In The Works By Ernest Hemingway

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.     

Achieving Unusual States of Matter Under High Pressure

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-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

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-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

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     

Call for Papers

<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     

Journal of Donghua University ( English Edition) Contents of Volume 31

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Brief Introduction to “Journal of Jilin University( Science Edition) ”

<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has