垂直腔表面发射激光器的研究

垂直腔表面发射激光器(VCSEL)是一种应用于光纤通信系统的低成本、高性能的特定波长光源,它具有测试简单、易耦舍以及易形成阵列等独特优势,已在光并行互连及高密度光存贮等领域得到大规模应用.文章介绍了VCSEL的结构和当前的制造工艺水平,阐述了各波段VCSEL的发展和应用现状,探讨了VCSEL在不同领域中的应用范围并指出了VCSEL的发展前景.     

用于空间光互连的850 nm VCSEL 4×4阵列的热场模拟

作为空间光互连系统的发射部分,垂直腔表面发射激光器(VCSEL)阵列的热特性直接影响到光互连系统的稳定性。建立了850nm VCSEL 4×4阵列的热场数学模型,并利用有限差分法求解热传导和热扩散方程,得出了在VCSEL单元工作电流为10mA时阵列的热场分布:VCSEL单元有源层温度约为50℃;整个阵列的温度仅为38.65℃。依据此结果制作了850nm 4×4光互连模块,其每通道稳定传输速率达到1Gbit/s。     

光子晶体垂直腔表面发射激光器及其进展

单基模垂直腔表面发射激光器（VCSEL）是光网络数据传输、光互连、光存储、激光打印及军事应用中的重要器件。光子晶体是20世纪80年代末提出的新概念和新材料。目前,光子晶体垂直腔表面发射激光器（PC—VCSEL）是国际上研究的热点。介绍了PC-VCSEL的典型结构、制作工艺及进展。     

垂直腔表面发射激光器及阵列发展水平与应用市场

垂直腔表面发射激光器（VCSEL）是光通信中革命性光发射器件，其优异性能受到广泛关注，已成为研究开发的热点。VCSEL及阵列已有很大发展，并获得较广泛的应用。VCSEL及阵列作为一种很有发展前景的新型量子阱激光器，将有强大的生命力和更为广阔的应用市场。     

10Gb/s×12通道VCSEL驱动器阵列设计

采用0.18μm CMOS工艺设计了12通道并行垂直腔面发射激光器(VCSEL:Vertical CavitvSurface Emitt ing Laser)驱动阵列.仿真结果表明,1.8V电源供电时,该电路单通道输出调制电流可达30mA,工作速率为10Gb/s,最大可达12Gb/s,12路并行通道的总带宽为120Gb/s,该驱动阵列电路可用于高速芯片间光互连.     

40Gbit/s甚短距离并行光发送模块的研制

基于VCSEL激光器阵列,设计和制作了一种12信道的40 Gbit/s甚短距离并行光发送模块。模块单信道传输速率大于3.5 Gbit/s,12信道并行总传输速率高达40 Gbit/s。并行光发送模块以其高速率、高集成度以及低成本等特点,为短距离高速率并行光传输提供最具竞争力的解决方案之一。     

VCSEL技术与并行光互联

介绍了VCSEL结构和技术特点，它以很高的性能价值比成功地应用于单通道和并行光互联，并将在宽带以太网、高速数据通信网中得到广泛的应用，以VCSEL为基础器件的高速大容量、高并行处理功能的光互连、光交换系统有着极好的应用前景。     

基于梯度折射率透镜的850 nm光互连模块的研究

设计了波长为850 nm的4×4阵列光互连模块,利用ZEMAX软件对使用双柱面透镜和梯度折射率透镜的系统光路进行了模拟计算,通过比较,设计最终采用了对准容差更大的850 nm梯度折射率透镜.利用1×4的梯度折射率透镜阵列将1×4的850 nm垂直腔表面发射激光器(VCSEL)阵列和2×4的Si探测器阵列连接起来,经对准后组装成了1×4的线列光互连模块,模块的信号电流/串扰电流比大于0.53×105.     

基于VCSEL/MSM-CMOS技术的并行光互连设计

提出了一种基于VCSEL/MSMCMOS技术的并行光互连系统,详细介绍了系统整体设计,着重对光网络通信接口卡中的PCIHIPPI接口模块、HIPPIFIBER接口模块、光总线模块设计进行了阐述。     

选择液相外延法制备GaAs SNOM微探尖

使用GaAs（001）衬底模拟垂直腔面发射激光器（VCSEL）外延片表面，采用选择液相外延技术在其上面制备了用于超高密度光存储的扫描近场光学显微术GaAs微探尖阵列，并用扫描电子显微镜对微探尖阵列进行了表征．结果表明，在合适的条件下，微探尖呈金字塔状，并且有着较好的分布周期性．这对解决微探尖与VCSEL出光窗口的对准问题、批量制备问题和实现多探尖并行扫描具有实际应用价值．     

聚对苯撑苯并双(口恶)唑发光及其器件制备

采用光谱技术,研究了聚对苯撑苯并双(口恶)唑(PBO)溶液的光敏发光特性,并用相对法估算出溶液发光效率在50%范围.结合光谱技术、半导体电学和电化学等研究手段,具体研究了以PBO为发光层的单层电致发光器件,研究结果显示,电致发光与薄膜的光致发光有具有相同的发光中心,峰值位于510 nm左右.同时发现,由于存制备过程中不同处理条件使得不同厚度薄膜残留的掺杂物质浓度不同,从而引起薄膜的导电性的不同.使得器件的阈值场强随PBO厚度的减小而逐渐增加.     

系统级封装新型埋入式电源滤波结构的研究

在高密度小尺寸的系统级封装(SiP)中,对供电系统的完整性要求越来越高,多芯片共用一个电源网路所产生的电压抖动除了会影响到芯片的正常工作,还会通过供电网路干扰到临近电路和其他敏感电路,导致芯片误动作,以及信号完整性和其他电磁干扰问题.这种电压抖动所占频带相当宽,几百MHz到几个GHz的中频电源噪声普通方法很难去除.结合埋入式电容和电源分割方法的特点,提出一种新型高性能埋入式电源低通滤波结构直接替代电源/地平面.研究表明,在0.65～4GHz的频带内隔离深度可达-40～75 dB,电源阻抗均在0.25ohm以下,实现了宽频高隔离度的高性能滤波作用.分别用电磁场和广义传输线两种仿真器模拟,高频等效电路模型分析这种低通滤波器的工作原理以及结构对隔离性能的影响,并进行了实验验证.     

Emerging interconnects: a state-of-the-art review and emerging solutions

Aluminium was a primary material for interconnection in integrated circuits (ICs) since their inception. Later, copper was introduced as interconnect material which has better metallic conductivity and resistance to electromigration. As the aggressive technology scaling continues, the copper resistivity increased because of size effects, which causes increase in delay, power dissipation and electromigration. The need to reduce the resistor-capacitor??????? delay, dynamic power utilisation and the crosstalk commotion is as of now the fundamental main impetus behind the presentation of new materials. The purpose of this paper is to do a survey of interconnect material used in IC from introduction of ICs to till date. This paper studies and reviews new materials available for interconnect application which are optical interconnects, carbon nanotube (CNT), graphene nanoribbons (GNRs) and silicon nanowires which are alternatives to copper. While doing a survey of interconnect material, it is found that multiwalled CNTs, multilayer GNR and mixed CNT bundles are promising candidates and are ultimate choice that can strongly address the problems faced by copper but on integration basis copper would last for coming years.     

Arsenic deposition as a precursor layer on silicon (211) and (311) surfaces

We investigate the properties of arsenic (As) covered Si(211) and Si(311) surfaces by analyzing data from x-ray photoelectron spectroscopy (XPS) and low-energy electron diffraction (LEED) images. We then create a model using total surface energy calculations. It was found that both Si(211) and Si(311) had 0.68±0.08 surface As coverage. Si(211) had 0.28±0.04 Te coverage and Si(311) had 0.24±0.04 Te coverage. The Si(211) surface replaces the terrace and trench Si atoms with As for a lower surface energy, while the Si edge atoms form dimers. The Si(311) surface replaces all terrace atoms and adsorbs an As dimer every other edge site. These configurations imply an improvement in the mean migration path from the bare silicon surface by allowing the impinging atoms for the next epitaxial layer, tellurium (Te), to bind at every other pair of edge atoms, and not the step terrace sites. This would ensure a nonpolar, B-face growth.     

光子晶体微腔发光二极管

光子晶体微腔因其具有增强自发辐射、定向输出和单模工作的能力而受到广泛关注。介绍了光子晶体微腔发光二极管的基本原理、设计、特性、制作及其典型器件。     

Comparative study of maximum power point tracking techniques for hybrid renewable energy system

The power generation demand is increasing day-by-day throughout the world, therefore, the use of hybrid systems becomes a significant solution. The hybrid renewable energy system (HRES) is used for delivering power in various regions in order to overcome intermittence of wind and solar resources. Because of increasing environmental problems, for example, greenhouse gas emission and energy cost have interested novel research into substitute methods in favour of electrical power generation. Maximum Power Point Tracking (MPPT) control method is a vast deal of novel research used for enhancing the efficiency of HRES. The authors have revealed that the hybrid techniques i.e. Global MPPT, fuzzy-neuro systems, Adaptive Neuro-Fuzzy Inference System (ANFIS), Perturbed and Observe (P&O) + Adaptive Neural Network (ANN) etc. can provide best results as compared to other MPPT control methods. This paper offering a state of art review of MPPT control techniques for HRES.     

用于单光子TOF测量的时间-幅度变换器

基于新型共源共栅电流源的积分方法,设计了一种用于单光子飞行时间(TOF)测量的时间-幅度变换器(TAC)。该方法有效简化了TAC电路结构,减小了TAC占用面积,显著提高了TOF的满量程范围(FSR)。采用0.18 μm标准CMOS工艺设计。集成TAC的单光子探测器像素单元的填充因子可达到26.8%。后仿真结果表明,该TAC在120 ns的FSR内具有230 ps的定时分辨率,微分非线性(DNL)低于0.05 LSB,积分非线性(INL)低于1.1 LSB。蒙特卡洛仿真表明,512个TAC像素间的不均匀性低于0.5 %。该TAC非常适用于高密度时间相关的单光子计数(TCSPC)探测器阵列。     

多孔硅发光机制的分析

从量子力学的基本理论出发讨论了量子限制效应，推导出多孔硅有效禁带宽度增量并用量子限制效应和表面态及其物质在发光中作用的理论解释了ＰＳ光致发光的实验现象。     

一种基于分段CRC的LDPC译码的改进算法

级联多个循环冗余校验(CRC)的LDPC译码算法有效地改善了译码的收敛特性。然而在其译码算法中,当CRC检测的整体漏检概率不够低时,出现误码平台。因此,该文提出了改进算法,通过减少在译码算法中CRC检测的次数,降低整体漏检概率,提高了误码性能。仿真表明改进的算法提高了误码性能,译码复杂度也增加不大。     

Joint estimation of TOA and DOA in IR-UWB system using a successive propagator method

Impulse radio ultra-wideband (IR-UWB) ranging and positioning require accurate estimation of time-of-arrival (TOA) and direction-of-arrival (DOA). With receiver of two antennas, both of the TOA and DOA parameters can be estimated via two-dimensional (2D) propagator method (PM), in which the 2D spectral peak searching, however, renders much higher computational complexity. This paper proposes a successive PM algorithm for joint TOA and DOA estimation in IR-UWB system to avoid 2D spectral peak searching. The proposed algorithm firstly gets the initial TOA estimates in the two antennas from the propagation matrix, then utilises successively one-dimensional (1D) local searches to achieve the estimation of TOAs in the two antennas, and finally obtains the DOA estimates via the difference in the TOAs between the two antennas. The proposed algorithm, which only requires 1D local searches, can avoid the high computational cost in 2D-PM algorithm. Furthermore, the proposed algorithm can obtain automatically paired parameters and has better joint TOA and DOA estimation performance than conventional PM algorithm, estimation of signal parameters via rotational invariance techniques algorithm and matrix pencil algorithm. Meanwhile, it has very close parameter estimation to that of 2D-PM algorithm. We have also derived the mean square error of TOA and DOA estimation of the proposed algorithm and the Cramer-Rao bound of TOA and DOA estimation in this paper. The simulation results verify the usefulness of the proposed algorithm.