掺Er光纤宽带光源的研究和应用

简述了近年来国内外掺Er光纤(EDF)光源的最新发展,详细分析了EDF光源的工作原理;介绍了EDF的基本结构,并概述了其各自的特点;总结了当前几种重要的EDF光源及其研究状况;指出了未来EDF光源发展方向。     

Inherent gain flattening due to two mode interference in erbium doped coaxial fibers

In this paper we propose the use of an Erbium doped fiber (EDF) in coaxial configuration for gain flattening. The coaxial fiber supports two symmetric modes and can be designed to exhibit exchange of power between the amplifying doped inner core and the undoped outer core around the gain peak (1530 nm) due to interference among the two modes as it propagates along the coaxial fiber. This results in inherent gain flattening across the C-band as well as an increase in the average gain in the 1540–1560 nm band.     

基于单泵浦源结构的高平坦C+L波段掺Er3＋光纤宽带光源

为了实现高平坦的C+L波段放大的自发辐射光(AS E)光输出,提出并设计了一种 基于LD单泵浦源,并且采用两段掺杂浓度完全相同的掺Er3＋光纤(EDF)作为增 益介质的宽 带光源。对光源的基本原理及实现方案进行了理论分析和实验验证。首先,根据Er3＋ 能级 结构介绍C+L波段宽带光源 的产生原理。然后,设计系统结构,在结构中采用976nm LD作泵 浦源,通过耦合器将泵浦光按照一定比 例分为两路对EDF泵浦;采用两支波分复用器(WDM)将泵浦光耦合进入EDF,并通过 熔接环形镜(FLM)提高转换效率;输出端熔 接隔离器(ISO)防止端面回波对输出造成影响。最后,根据EDF的ASE增益 数学模型对EDF长度进行了分析和优 化。实验结果表明,用于调整C波段ASE光输出的EDF1长选用2m,用于调整L波段ASE光输出 EDF2长选为16m, 获得平坦C+L波段ASE光输出,在不使用任何滤波器的条件下,在1540～1610nm波段范围内光谱平坦度为±0.525dB,在 1520～1610nm范围内光 谱平坦度为±1.119dB。本文方法使用1支976nm LD实现了C+L波段的高平坦输出,简化了系统结构,并降低了系统成本。     

Study on parameter optimization in a passively mode-locked Erbium-doped fiber laser

Optical soliton communication is the frontier research topic of optical fiber communication. In this paper, we study optical solitons generated by passively mode-locked Erbium-doped (Er-doped) fiber (EDF) laser. We analyze the variation of nonlinear equilibrium point parameter N of the passively mode-locked EDF laser in the role of group-velocity dispersion (GVD) and small-signal gain, and adjusting system parameter N is as close as to possible to 1. The ground state first-order optical soliton which generated through system parameter optimization of the passively mode-locked EDF laser will improve the efficiency and stability of optical soliton communication system. The research of this paper will have provided the theoretical foundation of parameter optimization in a passively mode-locked EDF laser. And it will be possible for the passively mode-locked fiber laser in optical fiber communication system to be applied from the laboratory stage to the practical application.     

新颖的高平坦度高功率掺铒光纤光源

报道了在前向结构中光纤前端输出处加用3dB耦合器制作的光纤圈反射器形成双程后向输出结构,实现了一种高平坦化的高功率光源。通过调节抽运功率及光纤长度等参量,实现3dB带宽达35．28nm(基本完全覆盖C波段),功率为7．679mW(8．85dBm)和平均波长为1545．881nm的超荧光光纤光源(SS)。与常用技术相比,该技术更简单,实用,同时提高了光源效率,稳定性好,易于降低成本,设计方便。由于L波段的超荧光的本身平坦度较好,此方案可得到高平坦度的C L波段高功率宽带超荧光输山,尤其适用于需要高平坦度高功率超荧光的场合。     

The Role of the Liquid‐Solid Interface in the Preparation of Supported Catalysts

The contribution of the Interface Science to the preparation of supported catalysts during the last two decades is presented. It is illustrated how the concepts and the methodologies of the Interface Science could be effectively used for an in‐depth understanding of the phenomena involved in the initial preparation step. This, extremely critical step, concerns the deposition of transition metal species containing the active elements, from an impregnation solution, onto the surface of common catalytic supports. Moreover, the aforementioned concepts and methodologies allow the regulation of the mode of interfacial deposition and the local structure of the deposited species and, thus, the surface characteristics and the catalytic behaviour of the resulted catalysts.     

多波长光纤激光器的研究

以一种环形腔结构的 MW- EDFL为例 ,详细说明了多波长光纤激光器的结构特点、工作原理和研究现状 ,同时介绍了几种多波长光纤激光器的最新报道 ,并预言了多波长光纤激光器的广泛应用     

Linux2.6内核实时性分析与改进方案

分析了linux2.6内核的实时性,针对分时调度算法和粗糙的时钟粒度,提出一种改进方案.改进的Linux具有高精确度时钟系统和多种实时调度算法动态模块.实验表明,改进后的linux2.6内核在实时性方面有较大提高.     

非抢占式EDF算法下周期性任务的最小相对截止期计算*

现有的求解周期性任务最小相对截止期的方法均假定任务集是采取抢占式EDF调度算法,并不适用于当任务为基于非抢占式EDF调度算法的场合,如实时通信领域。在分析了非抢占式EDF调度算法的可调度性判定条件基础上,提出了基于非抢占式EDF调度算法下周期性任务最小相对截止期的计算算法。算法通过逐渐增加任务的相对截止期直到使任务集变为可调度的方式,实现某个任务相对截止期的最小化。仿真实验表明该算法具有较好的计算复杂度。