微光学陀螺波导谐振腔的优化设计

提出一种应用于微型光学陀螺的谐振腔的优化设计方案,优化设计方案同时兼顾微型光学陀螺精度要求与其系统微型化设计。光波导材料为传输损耗为0.01dB/cm的硅基二氧化硅材料,有效的降低了谐振腔内部的损耗,使得谐振腔内损耗仅为0.5dB,利于谐振腔的高精度;光波导结构采用准单模矩形结构,利用腔中的弯曲波导对一阶模的有效滤除实现了光的基模传输,利于谐振腔的小型化;此外分析了波导的传输损耗、波导耦合器分光比对谐振腔性能及陀螺极限灵敏度的影响,得出波导耦合器分光比的优化参数,并仿真得到谐振腔的谐振清晰度达到70以上。假定在激光光源线宽为30kHz,探测器响应度0.95A/W,积分时间为10s的条件下,仿真得到系统的极限灵敏度为1.6°/h左右。最后实验验证了此优化设计方法是有效可行的。     

用于波分复用的1×4多模干涉耦合器

根据多模干涉(MMI)技术和波分复用原理,设计并研制出应用于波分复用系统的1×4钛扩散铌酸锂(Ti:LiNbO3/LiNbO3)多模干涉耦合器.对MMI耦合器进行了理论研究和设计计算,完成了结构参数的优化设计、特性参数(损耗,分光比)的计算和实验验证,并与常规的M-Z型耦合器进行了对比.设计出的1×4MMI耦合器的长度为6 mm,损耗为1.4 dB,而使用三个M-Z型耦合器构成1×4耦合器,总长度为60 mm,总损耗为1.5 dB;因此,采用MMI耦合器,具有结构紧凑、损耗低、工艺简单、容差性好等一系列独特的优点.     

SOI纳米波导的优化制备与弯曲损耗测试

主要针对目前SOI(Silicon-on-insulator)纳米光波导结构弯曲损耗严重的问题,系统地进行了理论仿真分析,设计出最佳的纳米波导结构,并采用MEMS工艺对其进行加工制备与优化处理。后利用了SEM(扫描电子显微镜)、AFM(原子力显微镜)、透射谱功率法等研究手段精确测试了在高纯氮退火和BOE腐蚀后处理不变的情况下,不同温度热氧化退火处理下的波导侧壁粗糙度和对应的弯曲损耗,结果表明:波导的侧壁粗糙度随退火温度的变化近似呈二次抛物线变化趋势,在900℃附近达到最低值2.1 nm,对应的半径15μm的环形波导的弯曲损耗为(0.0109±0.001)dB/turn,其损耗值与理论分析结果一致。利用这一结论就可以通过选择不同的优化处理条件来减小环形波导的弯曲损耗,从而实现光能量的高效传输。     

熔融度对熔锥型光纤耦合器特性影响研究

光纤耦合器是现代光纤器件的一个主要部分,熔融拉锥方法是目前制造光纤耦合器应用最广的方法。熔锥型光纤耦合器在制作过程中受到很多种因素影响,文本主要研究熔融度对熔锥型光纤耦合器分特性的影响研究。本文选用合适的连续函数描述了熔锥型光纤耦合器在制作过程中锥形区的渐变特性和熔融度的关系,并建立熔融性光纤耦合器的结构模型。利用数值模拟的方法,讨论了光纤耦合器在不同的熔融度情况下,分光比、插入损耗、附加损耗的变化情况。得出熔融性光纤耦合器的分光比随熔融度周期变化,对于同一种光纤耦合器,周期随着熔融度增加而越来越小。对于不同光纤耦合器,随着光纤耦合器的长度减小,每个周期的长度增加。这对生产中控制光纤耦合器分光比提供了重要的理论依据。     

一种基于SOI的集成光波导耦合系统的设计与制备

根据锥形光纤与平面环型微腔耦合原理,使用L-Edit版图设计软件设计并优化了锥形光波导与微腔耦合系统。利用MEMS工艺对SOI圆晶片进行加工,从而实现了锥形光波导与跑道型以及环型光波导微腔的集成。其中,光波导以及微腔通过ICP刻蚀顶层硅而成,矩形槽通过RIE刻蚀衬底硅而成。光波导两侧的矩形凹槽可方便光纤接人以及对出射光...     

一种新型谐振式MOEMS陀螺的设计及分析

提出一种新型的利用空间光路敏感Sagnac效应的谐振式MOEMS陀螺,设计了利用微镜构成的光学谐振腔.此结构具有小型化优势,可利用MOEMS工艺进行加工.理论分析了光源及谐振腔参数对陀螺基本探测极限的影响,指导参数设计,得到陀螺的极限灵敏度为1.54°/h.通过模式匹配理论对谐振腔型式进行了改进,减小了谐振腔损耗.进行了谐振腔原理验证实验,观察到谐振曲线.最后对微谐振腔的加工工艺进行了讨论.     

熔锥型光纤耦合器制作参数测定与分析

光纤耦合器是一种用于实现光分路与合路的光元源器件,它在光纤通信与信号处理等方面得到了十分广泛的应用。本文主要研究分析不同分光比对制作2×2光纤耦合器的影响,得出了基于OC-2020型光纤熔融拉锥机制作分光比为50%、60%、70%、80%、90%的耦合器时的最佳设定分光比。     

高精度光纤陀螺磁屏蔽技术

针对外界磁场的存在对高精度光纤陀螺的工作性能产生严重的干扰问题,提出了一种对该类磁屏蔽结构设计进行优化的方法,分析了光纤陀螺磁屏蔽结构中各参数对整体磁屏蔽效能产生影响的理论,建立了磁屏蔽结构模型,并主要针对其几何结构参数进行了详细的扫描仿真,最终进行组合优化,使其满足特定指标要求。该方法对光纤陀螺的磁屏蔽结构设计与优化具有一定的参考意义。     

光波导加速度传感器中3dB耦合器设计

光波导加速度传感器是一种实用型加速度传感器,目前广泛应用制备光学加速度计的迈克尔逊、马赫—曾德等干涉仪的核心部件都包含3 dB耦合器。3 dB耦合器的设计对光波导加速度传感器的检测精度尤为重要。介绍了所设计的光波导加速度传感器的工作原理,设计了3 dB耦合器波导的结构和参数,并用光学模拟软件OptiBPM对3 dB耦合器进行模拟。结果表明:所设计的3dB耦合器具有良好性能,符合设计要求。     

取代机电陀螺的光纤速度陀螺

在新的设计领域和业已存在的应用当中,光纤陀螺正开始取代机电陀螺,由于具有较高的可靠性、对“g”不敏感以及良好的抗冲击和震动等特性,在运动物体和军事技术应用中光纤陀螺将甚为理想。和激光陀螺一样基于SAGNAC效应的光纤陀螺（FOG）自首次报道至今已有20年了,光纤陀螺有闭环和开环两种结构。但由于前者成本高,当前只有开环结构的光纤陀螺用来取代机电速率陀螺,基于全光纤概念,用缠绕于椭圆柱体的光纤环、耦合器和偏振器,我们已成功地开发了一系列低成本的光纤陀螺。     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.