采用CCD的空间光通信光斑位置提取重心算法的分析及实验

对采用CCD的空间光通信光斑位置提取重心算法进行了理论分析,对不同程度光束偏转的APT系统光斑位置定位及无空气扰动条件下背景光对光斑位置定位的影响进行了实验研究。     

星地激光通信复合轴APT系统仿真研究

为了满足高效星地激光通信的要求,研究了一种复合轴APT（Acquisition、Pointing、Tracking,APT）系统,在分析直流电机驱动转台和压电陶瓷振镜的结构和工作原理的基础上,构建了相应的数学模型,并设计控制器.分析了卫星平台振动、离散扰动和大气抖动对系统跟踪性能的影响,利用振动功率谱和光斑漂移分布函数给出扰动源的数学描述.在数学模型的基础上构建完整的系统仿真模型,仿真实验结果表明,复合轴APT系统具有良好的运动跟踪性能和抗高频干扰能力.构建的仿真系统可以很好的指导实际系统的分析设计和评估.     

大气激光通信中的APT技术研究

在空间激光通信系统中,空间光束的自动搜索、跟踪、瞄准,即APT(Acquisition,Pointing and Tracking)是一项非常关键、非常重要的技术。文中对APT的工作原理、工作过程以及大气空间环境对APT系统的影响等进行了分析。     

高空平台不稳定对平台间光通信性能的影响及抑制

考虑晃动对平台间光通信的影响,结合Γ大气扰动模型,推导出平台间光通信的误码率表达式,进一步分析平台晃动条件下平台间光通信捕获、跟踪和瞄准(APT)系统的设计要求。结果表明,发送端偏转和接收端的垂直运动对平台间光通信性能影响较大,而接收端偏转和发送端的水平运动对平台间光通信性能影响较小;满足平台间光通信误码率小于10-6的APT系统瞄准精度应低于50μrad。     

激光加工中光束变换技术研究

激光光束形状和能量分布直接限定了激光加工的应用.为满足不同的激光加工要求,必须对激光光束进行光束变换.应用旋转棱镜和组合光学系统能够实现实心和环状光束之间的相互变换.从几何光学角度对旋转棱镜组合光学系统进行了理论分析和实验.通过调整正负旋转棱镜的间距d,荻取不同形状和能量分布的激光光束.实验结果表明,基于旋转棱镜组合光学系统的光束变换技术,有效地实现了多种形式的光束变换,提高了激光束的利用率,在激光k_T-领域中具有广泛的应用前景.     

舰载激光武器稳定平台粗精复合控制

为了实现舰载激光武器在复杂作战环境中对目标的精确毁伤,提出一种基于快速反射镜的粗精复合稳定平台,用以控制激光光束的稳定精度。首先,介绍了系统组成及工作原理,设计了压电陶瓷驱动的全柔性精级快速反射镜,并且分析了该快速反射镜的性能特点。然后,设计了粗精复合控制系统,在此基础上探讨了粗精复合稳定平台各组成单元之间的相互影响因素。最后,通过理论计算推导了粗精复合控制系统的误差传递函数,并搭建了实验平台,进行了稳定精度测试实验。实验结果表明:在四级海况摇摆扰动条件下,相较于传统粗级稳定平台,方位复合平台的稳定精度从191.6 μrad提高到6.7 μrad,提高了约27.6倍,俯仰复合平台的稳定精度从121.3 μrad提高到4.9 μrad,提高了约23.8倍;在各种外界摇摆扰动下,粗精复合平台对激光光束的稳定控制精度均≤10 μrad。满足了舰载激光武器平台对激光光束高精度稳定控制的作战需求。     

运动旋转基线单站无源定位CRLB分析

针对仅用相位差变化率进行的单站无源定位，现有文献一般考虑干涉仪基线固定在观测平台上，并随其作某种机动下的定位效果，并未考虑基线自身旋转的情况，因此考虑观测平台机动，干涉仪基线自身旋转的情况，提出了基于运动观测平台旋转基线的无源定位方法，并对观测平台机动过程中基线自身不断旋转情况下的定位原理及其性能进行了分析，推导了该方法定位误差的克拉美罗下限（CRLB），仿真实验结果表明，该方法很好地改善了定位性能。     

空间光通信APT技术分析

在空间光通信系统中，空间光束的自动搜索、跟踪、瞄准，即APT(Acquisition，Pointing and Tacking)是一项非常关键、非常重要的技术。文中对APT的工作原理、关键技术等进行了分析。     

机载激光通信系统精跟踪单元变结构控制技术

APT(Acquisition Pointing Tracking)复合轴子系统是机载激光通信系统的核心技术,也是实现机载激光通信的前提和保证,其中,精跟踪单元对粗跟踪残差进一步抑制,决定着整个复合轴的跟踪精度,是APT系统的核心部分.通过对精跟踪伺服单元结构的分析及复合轴APT系统对精跟踪单元的要求,设计了精跟踪的控制函数模型.根据不同飞行平台振动环境的特点,实现了变结构的精跟踪智能控制,使精跟踪的控制精度达到最优,并进行了MATLAB仿真验证.最后,经过APT复合轴的室内实验系统测试得出:在几种典型的机载平台环境下,最终的跟踪精度都保持在3 μrad左右.     

星地光通信中的精跟踪系统远场验证

 在星地光通信中,精跟踪系统的性能决定了整个APT系统的跟踪精度和带宽,是通信成败的关键因素。基于大容量图像数据实时处理和复杂控制,设计基于FPGA的并行处理精跟踪系统。跟踪控制算法采用自适应模糊－神经网络算法,可以实现系统参数在线实时动态调整。通过16Km的精跟踪系统演示实验,精跟踪系统抑制了平台振动和大气湍流对接收光功率的影响,有效提高了通信光束1550nm的光功率耦合效率,通过实验数据分析,精跟踪系统的跟踪精度达到了4.87μrad。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.