用拉盖尔——高斯函数表示梯度型单模光纤的特性参数

本文用拉盖尔－高斯函数来表示梯度单模光纤的特性参数。恰当应用拉盖尔多项式的性质和汉格尔变换理论，光纤参数如远场分布，模斑尺寸等可以有解析式计算，结果十分简单且物理意义明确。文中给出了数值计算结果并与准确值进行了比较，最后讨论了本文方法的优点     

用拉盖尔—高斯函数展开方法计算梯度型单模光纤特性参数

用拉盖尔－高斯函数展开方法计算梯度型单模光纤特性参数。应用拉盖尔多项式性质和汉克尔变换来计算光纤参数：如远场模斑尺寸和波导色散，得到了非常简单且物理概念清晰的表达式。给出了数值计算实例并与精确值进行了比较，讨论了该方法的优点和缺点。     

一种新型光学匹配滤波器的研制

讨论了用计算全息方法研制的用于单模光纤场分布测量的光学匹配滤波器，给出了一个含有９个低阶高斯－拉盖尔模的光学匹配滤波器实例及其再现像。     

用矩阵法计算任意折射率剖面单模光纤的传输参量

用拉盖尔－高斯级数逼近单模光纤中横场，不多的几项即可达到很高的精度。文中给出了该方法的理论推导，并用相应的程序进行了验证。该法对任意的圆对称折射率剖面光纤计算传输常数和色散能够得到满意的结果。     

光纤激光及其相干合成光场的准确分析

为了准确地研究光纤激光及其相干合成光束的远场传输特性,采用将LP01模分解为许多不同拉盖尔-高斯模叠加的方法,分析了LP01模以及多个光纤激光相干合成光束的传输光场分布和光束质量,并与用高斯函数表示的光纤激光的光场进行了比较.分析中发现,基模高斯光束与LP01模的初始场分布基本相同,但传输后的光场分布会产生较大误差,在光纤激光相干合成光场的分析中两者间的差别也非常明显.结果表明,为更准确地分析光纤激光及其相干合成光束的传输特性,光纤激光的模场表达式应采用拉盖尔-高斯模的叠加式.     

利用普通熔融拉锥机实现光子晶体光纤拉锥

光子晶体光纤的拉锥是实现光子晶体光纤潜在应用价值的重要技术手段。通过优化普通光纤拉锥机的参数,利用"快速低温"拉锥法有效控制了光子晶体光纤空气孔的相对塌缩。实验中实现了两种不同光子晶体光纤的拉锥,光纤外径分别从原来的125μm拉锥到50μm和30μm,光纤的孔直径和孔间距之比基本保持不变,拉锥损耗小于0.4 dB。基于普通熔融拉锥机的光子晶体光纤低损耗拉锥为光纤器件的制作奠定了基础。     

基于强耦合理论的熔锥型单模光纤耦合器研究

根据光纤的强耦合模理论，阐述了熔融拉锥型光纤耦合器的工作基理，并研究了熔融拉锥法制作单模光纤耦合器的过程，分析了各参数对耦合器性能的影响，利用光学测试系统测试了光纤耦合器各光学特性参数。经大量实验表明，强耦合模理论与实验结果吻合，说明该方法的可行性；同时拉锥法制作的光纤耦合器具有较好的性能特性，表明该方法具有制作过程简单、附加损耗低、方向性好、均匀性好、环境稳定以及成本低廉等优点。     

边缘检测技术在光纤微加工系统中的应用研究

针对光纤成像的特殊性，提出了一种利用边缘检测算法来提取ROI区域作为对焦窗口的方法，该方法成功地消除了光纤图像中心亮带对清晰度评价值的影响，可准确判断光纤目标清晰的位置，结合显微视觉测量技术，将其应用于光纤侧面抛磨和拉锥系统中，经过亚像素边缘检测及尺寸计算后，对光纤参数的测量精度高于0.5μｍ，可提高光纤微加工系统的性能。     

截断拉盖尔-高斯光束的MG2因子

用广义截断二阶矩方法对截断圆对称拉盖尔高斯光束的广义光束传输因子(MG2因子)作了研究,得到了MG2因子的解析公式,并用数值计算例作了说明。研究表明,截断圆对称拉盖尔高斯光束MG2因子与截断参数和光束的阶数有关。随着截断参数的增加,MG2因子逐渐趋近于无截断圆对称拉盖尔高斯光束的光束传输因子值。     

光纤耦合器的制造设备

本文介绍光纤耦合器的制造设备。该设备采用光纤熔融拉锥工艺，在预设了工艺参数和分光比后，能自动完成耦合器的生产过程。制成的Ｘ型单模光纤耦合器的附加损耗小于０．２ｄＢ，分光比误差小于２％，成品率９０％。     

Communications — the emancipation of the small business

Many new services have been introduced to help people communicate. In the business arena, large enterprises have been well served by new services. However, small-and medium-sized businesses (SMBs) have suffered as customisable services at cost-effective prices have not been available. Only recently has new technology been able to assist this market segment. The specific requirements of the SMB sector are examined in this paper and propositions to address these requirements are discussed. A shared platform architecture to deliver the services to the SMB market-place is considered in detail. HP     

基于LABVIEW的光收发模组的测试平台及测试分析

文章以光发射组件TOSA和光接收组件ROSA为主要硬件,LABVIEW7.0为软件开发测试平台,对已组装好的光收发模组的性能进行测试,并分析不同温度下的测试眼图和数据结果,完成测试任务。最后对测试中存在的问题进行了总结和展望。     

A high-density, matched hexagonal transistor structure in standardCMOS technology for high-speed applications

In this paper, a very dense CMOS hexagonal transistor structure is presented. The main advantages of the transistors are the low parasitic drain and source capacitance caused by the small area. The matching properties of this structure have been investigated, and these results have been compared with those for traditional finger-style structures. Exploiting the advantages, these transistors are very well suited for high-speed applications with a demand for both good matching and a small area, such as multibit current steering D/A converters or wireless applications. The test chips have been implemented in a standard 0.5-μm CMOS technology. No adaptations to the standard technology have been made to realize the structures     

Quantum interference effects in semiconductors: a bibliography

The bibliography has been compiled as an introduction and study guide to this field. The papers listed describe the extensive theoretical and experimental results that have been obtained on quantum interference effects and discuss possible application areas. Works of a fundamental nature concerning phenomena that are basic to all semiconductor behavior have not been included. Articles on the properties and band structure of semiconductors, which are essential to a complete understanding of quantum interference effects, have not been included. Conference papers, though frequently very important, have not been included to conserve space. The papers are listed alphabetically according to the first author's surname. As in the compilation of any bibliography, numerous valuable and pertinent articles have probably been inadvertently omitted     

测量传声器驻极体背极的制作及分析

本文介绍了测量传声器中驻极体背极的部分制作技术,并对驻极体材料的性能进行了高温外推测定和分析。在实验基础上,对微型驻极体样品的极化装置进行了改进。本文可供从事传声器生产和研究的有关人员参考。     

Freeway traffic surveillance and control

In the past decade, automatic freeway surveillance and control systems have been introduced in several cities in the United States. Effective use of the hardware that has been implemented requires a sound mathematical basis for evaluation and optimization studies. In this paper, the nature of freeway congestion and the structure of systems which have been implemented to relieve this congestion are discussed. Mathematical models of freeway traffic which allow consideration of on-ramp metering control are developed. Finally, several freeway traffic-control problems are discussed, current approaches are described, and formulations of improved (optimal) approaches are developed.     

Simulation Investigation of Millimeter Wave Varactor-tuned Transmission Cavity-stabilized Oscillator

A new circuit configuration for millimeter wave varactor-tuned transmission cavity-stabilized oscillator has been proposed in this paper. Compared to conventional varactor-tuned reflection cavity-stabilized oscillator, in this configuration, a high quality factor transmission cavity directly coupled to varactor diode is employed to improve the performances of the oscillator. The operation frequency of this oscillator can be tuned by varying the resonant frequency of the transmission cavity through changing bias voltage of the varactor diode. An equivalent circuit model for the oscillator has been presented in order to theoretically investigate the performance characteristics of the oscillator. On the basis of this model, electrical tuning characteristics have been studied. Mode jumping phenomena during electrical tuning process have been analyzed for obtaining stable operations of the oscillator. The analytical formulae of quality factor and efficiency have been derived in terms of relevant circuit parameters. Particular emphasis has been paid on several circuit parameters which have a substantial impact on circuit performance. Some design considerations have been pointed out according to the simulation results, which are useful to the design and fabrication of this type of oscillators.     

Precharged CMOS quaternary logic encoder-decoder circuits

Multiple-valued buses have been proposed as a way of overcoming the interconnection complexity of VLSI. In this paper we present efficient new encoder-decoder circuits for four-valued bus signalling in clocked CMOS VLSI systems. The important advantages of our designs are that they can be implemented by standard binary CMOS processes, and are considerably simpler than earlier designs. Furthermore, they have no static power dissipation. The circuits have been extensively simulated using SPICE and have been found to operate reliably.     

一种基于MESH结构的空天信息网络模型

提出了一种基于MESH结构的空天信息网络模型.通过分析空天信息网络具有的特点,给出了空天信息网络的体系结构和协议栈模式,并分析了基于MESH结构的空天信息网络需要解决的关键问题及其可行的解决方法.     

IP网络服务质量保证技术

现有的IP网络本身没有特别考虑对业务服务质量的保证技术,无法满足综合业务的应用。几年来,业界提出了一些针对IP网络的服务质量保证方法,但是并没有真正在现有网络中普及应用。随着下一代网络的提出,网络服务质量保证技术已经列为其核心技术,只有该技术得到解决,基于IP的下一代网络才能够满足电信级网络的要求。简要分析了服务质量的要素,梳理了服务质量保证的几个关键技术,并对这些技术的原理和特点进行了简要分析。