面向超宽带信号处理的光频梳产生技术

针对未来电子信息系统对超宽带信号高速并行处理的需求,提出了一种可应用于光子超宽带信道化处理的相干光频梳产生方法,利用非线性效应实现高重频多梳齿的相干光频梳产生,并且重频及重频差可调谐。通过级联电光调制器产生初始相干光梳,对波分解复用选定的种子梳齿进行注入锁定,并通过非线性光纤、单模光纤及色散平坦光纤的组合模块对锁定后的梳齿复制和展宽,得到了80 GHz和79.4 GHz高重频、平坦度3 dB以内20根梳齿的相干光频梳,能够实现Q/V频段超宽带信号的接收处理,为综合射频一体化、大容量卫星通信等应用宽频段覆盖、大瞬时带宽射频信号的接收处理提供支撑。     

超宽带信号在高斯噪声中传播性能的研究

超宽带无线通信技术使用微弱的、持续时间极短的脉冲进行短距离通信。超宽带信号具有极宽的射频带宽和较低的中心频率，这种特性可使短距无线通信利用较低的发射功率进行高速传输。根据信号的频谱及其在高斯噪声中的传播性能，研究超宽带信号的减少衰减余量特性，给出不同进制波形的PPM调制超宽带信号比特误码率仿真分析。     

一种超宽带等效采样接收机的设计与实现

脉冲超宽带雷达回波信号由于带宽大而难以直接采样,通常采用等效时间采样方法来进行模数转换。传统的等效采样接收机大都是基于改变ADC采样时钟的时延来实现等效采样,采样时钟对触发信号会产生亚稳态时序,不可避免地会出现数据误对齐,必须添加辅助的在线或离线校正设计。针对这一问题,设计了一种基于FPGA内置延迟线的超宽带等效采样接收机,FPGA产生延时可调的发射触发信号去控制波形产生系统,基于高速采样保持器和ADC完成回波接收,实现了超宽带射频信号的等效采样,而无数据误对齐问题。接收机的等效采样速率为12.8GS/s,-3dB采样带宽为6.4GHz,满足脉冲超宽带雷达的应用需求。     

应用于超宽带雷达干扰的光学射频存储技术研究

针对超宽带雷达信号复制转发式干扰应用,研究了一种基于光处理的超宽带模拟射频存储技术,相比传统的数字射频存储技术,它大幅提升了干扰源的瞬时带宽。结合对光学射频存储的理论分析结果,采用低噪声光学放大与光学自适应幅度均衡技术精确控制光纤复制环路增益,实现对采样信号的高质量、大数量的相参复制。利用可调光纤延迟技术实现拖距、拖速等干扰效果,并通过实验验证与仿真分析证明了光学射频存储技术的可行性及有效性。     

一种超宽带频率综合器电路的设计与实现

基于超宽带射频（RF）收发电路的应用,设计了一种正交输出的超宽带、全集成并且可重构的频率综合器,可适用于25 MHz～12 GHz工作频段的射频接收、发射电路中射频信号的上变频和下变频处理。采用电荷泵频率综合器作为整体实现架构,使用双核压控振荡器（VCO）覆盖频率范围,利用多级级联本振信号生成技术产生本振信号,实现了适用于多频段一体化通信、雷达无线电跳频、软件定义无线电的频率综合器。采用CMOS工艺进行了设计仿真和流片,芯片尺寸为0.658 mm×1.2 mm。测试结果表明,12 GHz相位噪声不大于-85 d Bc/Hz@100 k Hz offset,电路典型总功耗为203 m W。     

基于异采样率的频率解算技术

采样保持器可有效扩展模拟带宽,后级模数转换器(ADC)以较低的采样率即可完成对超宽带射频信号的采集处理。由采样定理可知,当信号带宽超过采样率的1/2时,会产生频率模糊。提出了一种基于异采样率解频率模糊的算法,可适应输入射频信号带宽数倍于采样率时的频率解模糊,分析该算法原理以及关键参数设置,采用实例对该算法的可行性进行验证。     

基于频谱压缩接收的宽带/超宽带线性调频信号参数估计

该文提出了一种新的宽带/超宽带线性调频信号的接收方法, 它将宽带/超宽带线性调频信号通过射频通道的频谱压缩网络变成窄带信号,数字域用逆频谱压缩函数对压缩信号进行非线性重构,原线性调频信号的调制斜率和初始频率可通过重构信号精确估计。计算机仿真证实了算法的有效性。     

基于启发式蚁群算法的高保真信号重构

在当前的雷达射频半实物仿真系统应用中,有源干扰信号和雷达目标回波信号的模拟主要通过宽带数字射频存储技术(DRFM)实现。随着雷达瞬时工作带宽和捷变频范围的增大,如何实现对超宽带雷达信号的高保真重构是实际工程中面临的重要难题。文中基于启发式蚁群算法,结合数字信道化思想,实现了在现有有限的硬件平台基础上,对超宽带雷达信号的高精度重构。最后,通过仿真和实验验证了该方法的有效性。     

超宽带信号的光学产生方法以及应用

为了实现跨越不同网络的无间断服务和随时随地的高速率数据接入,提出了采用光学方法产生超宽带信号的技术,该技术的采用避免了额外的电光或者光电转换,节省了系统资源,有益于全光网络的形成。基于国内外的诸多研究成果,首先对利用光学方法产生超宽带信号的技术方案进行了认知与分析,在此基础上,以元器件为分类标准归纳总结出三类在光领域中产生超宽带信号的方法;然后结合实例对超宽带信号进行了应用分析,证明了超宽带信号的实用性与优越性;最后指出了超宽带系统未来的发展趋势以及存在的问题。     

基于扫频激光器的超宽带线性调频信号产生传输研究

提出了一种基于扫频激光器的超宽带线性调频(LFM)信号产生和传输的方法。该方法使用扫频激光器产生频率随时间周期性变化的光信号,注入马赫-曾德尔调制器后产生载波抑制双边带光信号,利用嵌有光纤光栅(FBG)的Sagnac环完成双边带光信号的分离。Sagnac环的透射光信号经延时后与反射光信号拍频,从而产生了超宽带LFM信号。仿真分别产生了载频30 GHz、带宽16 GHz、时宽带宽积8000的超宽带连续波LFM信号和超宽带脉冲波LFM信号。所提方案解决了天线拉远场景中超宽带LFM信号经光纤传输时的功率周期性衰落问题。在多目标探测分析中,方案产生的信号表现出高精度临近目标分辨能力。所提方案具有载频、时宽、啁啾率和啁啾符号独立调谐的优点,可实现高载频、超宽带LFM信号的产生和功率周期性衰减抑制传输。     

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.