激光链路终端发展及展望

利用激光建立星间链路不仅具有极高的潜在通信数据率(可达100Gbps以上)、较小的终端体积和重量，并且具有很强的抗干扰能力和保密性，又可以减少地面站，因此各国都非常重视此项技术的研究．随着低轨小卫星数量的显著增加，需要高数据率、低功耗、体积小、价格低的星上通信终端，激光星间链路终端正是满足了这种需求．     

各种激光星间链路特点分析

通过对不同激光星间链路特点的分析,找出应用于不同链路的空间光通信系统研制中所面临的主要问题,这有利于今后空间光通信研究的进展。     

激光星间链路中振动补偿技术研究

提出了一种在激光星间链路过程中的卫星平台振动补偿方案。采用CCD探测器代替角度传感检测振动,简化了卫星光通信跟瞄系统。在激光星间链咯中,卫星平台角振动对光束的跟瞄有较大的影响,采用前馈补偿方式实现较好的抑制。在实验室中建立了卫星平台振动模拟装置和前馈振动补偿系统,针对卫星平台的实际振动情况进行了模拟实验。结果表明,对于100Hz卫星平台角振动,当CCD采样频率大于1kHz时,补偿后的瞄准误差与补偿前相比下降了71％。     

激光星间链路中天线扫描捕获技术实验室模拟研究

对激光星间链路中的天线扫描捕获技术进行了理论分析和模拟实验研究。首先建立了天线扫描捕获理论模型 ,在此基础上对影响系统捕获性能的各主要参量之间关系进行了数值仿真分析。设计实现了一套天线扫描捕获实验室模拟系统 ,通过模拟实验对部分数值分析结果进行了验证 ,实验结果与数值分析结果基本符合。     

卫星间第一条使用激光的光学链路

卫星间的第一条光学链路建于2001年11月,该链路使用激光作为信号载体。从那时起,卫星已能实时把图像从空间传输到地面,从而使数据的发送更为及时。 这条实验用的光学数据链路是由安装在法国地球观测卫星SPOT-4号上的“半导体激光器卫星间链路实验”(SILEX)通信终端提供的     

多层卫星网络激光星间链路空间特性仿真

多层卫星网络结构由于其鲁棒性强,可实现无缝覆盖等特点而成为研究热点。针对 高轨/中轨/低轨(GEO/MEO/LEO)多层卫星网络结构,研究了各个节点间的激光链路,推导出 了 不同轨道间两个卫星位置关系的坐标转换公式。对同层间激光链路(OISL)、异层间激光链路 ( OIOL) 俯仰角、方位角以及距离参数和GEO对LEO覆盖特性进行了仿真。结果表明,卫 星光学终端俯仰指瞄范围完全可以满足目标星的移动要求,但水平指瞄范围和扫描速度是影 响星间激光链路性能的主要因素。     

高轨卫星激光中继链路研究现状及发展趋势

自由空间激光通信技术长期以来都是卫星通信和载荷技术领域的研究热点,具有大带宽、高速率等特点.高轨中继卫星是星间数据传输的骨干节点,随着激光通信技术的成熟,激光通信链路已成为国内外高轨中继卫星数据传输的可靠途径.对国内外高轨卫星激光中继链路的最新发展动态及其未来发展规划进行综述,该综述为我国建设空间激光信息网络提供参考.     

空间激光通信系统进展

描述了空间激光通信的特点,简单介绍了国际上几个空间激光通信发展先进国家在激光通信领域的发展动态,指出了空间激光通信的发展趋势.     

卫星互联网星间激光通信链路传输与路由交换技术研究（特邀）

随着低轨卫星互联网的迅猛发展,星间激光通信链路成为低轨大型星座互联互通的关键,也是用户接入卫星互联网实现全球范围内端到端交互的基础。与地球同步轨道的星间环网不同,由于低轨卫星的高动态性,造成星间链路需要不断动态重构,由此带来空间节点的编址方式、交换路由方法等诸多技术难题,是目前该领域关注的热点。此外,用户终端通过微波链路接入卫星互联网,需要微波链路与激光链路之间的汇集和分发,也是迫切需要研究解决的重点难点问题。     

地面站与ETS—VI间的光学星间链路试验

通信研究实验室（CRL）已经开发了一种光学卫星通信系统，并计划进行基本的光学通信试验，试验拟采用将于1993年发射的日本工程试验卫星VI（ETS－VI）上的通信系统。目前，ETS－VI的光学通信载荷，即激光通信设备（LCE）正在研制中。装备直径1．5m望远镜的地面光学设施已经基本完成。在卫星通信试验中，将建立一个双向光通信链路，并且，一些基本的光学通信试验如光束定位／跟踪，数据传输，飞行器姿态精密确定和光通过大气层的传输等也将要开展。本文描述了试验计划的基本概况和在研系统的当前状况。     

Optical intersatellite link with direct detection: The laser diode-pumped Nd laser option

Following a brief introduction reviewing various laser systems suitable for ISL, a typical link budget for an optical ISL with a Nd laser is calculated. Laser diode pumped Nd lasers are described, and several host materials are considered. Modulation formats and typical receiver performances for direct detection are examined in order to compute the minimum transmitted power required for the proposed link. Results show that laser diode pumped Nd laser systems are competitive for optical ISL.     

星间链路技术的研究现状与发展趋势

星间链路技术是提高全球卫星导航系统的精度和自主导航能力的一项关键技术。介绍了全球主要卫星导航系统星间链路的建设情况,综述了国内外关于星间链路的重要研究,包括星座的特性分析、星间链路的构建准则、星间链路的拓扑分析、星间链路传播信号的设计以及星间链路信号的发射和接收等,指出了目前研究的侧重点,展望了星间链路的发展趋势和未来的研究方向。相关内容可为星间链路的进一步研究提供参考。     

先进激光加工机的市场回顾与展望

继传统的CO2激光器和YAG激光器之后，先进激光加工机于2001后陆续进入市场。LD泵浦的高功率YAG激光器、THGYAG激光器、半导体激光器、光纤激光器、飞秒激光器和盘形激光器统称为先进激光加工机。     

美国机载激光器研发近期进展情况及未来前景

机载激光器（ABL）是目前美国研发的各种定向能武器中较为成熟的一种。到2010年,ABL项目已经进入了实际拦截试验阶段。本文首先回顾了2010年内ABL的各次拦截试验情况,然后对ABL项目通过这些试验所取得的主要成绩进行了简单总结,并对该项目当前面临的主要问题进行了分析,最后简要介绍了ABL项目的现状及其未来前景。     

三维集成技术的现状和发展趋势

给出了三维技术的定义,并给众多的三维技术一个明确的分类,包括三维封装(3D-P)、三维晶圆级封装(3DWLP)、三维片上系统(3D-SoC)、三维堆叠芯片(3D-SIC)、三维芯片(3D-IC)。分析了比较有应用前景的两种技术,即三维片上系统和三维堆叠芯片和它们的TSV技术蓝图。给出了三维集成电路存在的一些问题,包括技术问题、测试问题、散热问题、互连线问题和CAD工具问题,并指出了未来的研究方向。     

有机电致发光元件的现状与未来

有机电致发光 (OEL)元件又称为有机发光二极管 ,是一种面发光元件。它由直流低电压驱动 ,发光色从红、绿、蓝 (RGB)三原色到白色 ,自由度较大 ,因此有望成为新一代平板显示器。目前作为车载音响和手机的显示器已达到实用化 ,今后有望得到进一步发展。用于OEL元件的材料大体可分为两种 :一种是低分子量的荧光色素和金属络合物等小分子类材料 ;另一种则是将π共轭聚合物和色素高分子化的含色素聚合物等聚合物类材料。人类对小分子类的研究始于 2 0世纪 6 0年代初 ,对蒽单晶施加电压时观测到发光 ,后经薄膜化和层叠化处理提高了效率和亮度…     

Current status and future trends of SiGe BiCMOS technology

The silicon germanium (SiGe) heterojunction bipolar transistor (HBT) marketplace covers a wide range of products and product requirements, particularly when combined with CMOS in a BiCMOS technology. A new base integration approach is presented which decouples the structural and thermal features of the HBT from the CMOS. The trend is to use this approach for future SiGe technologies for easier migration to advanced CMOS technology generations. Lateral and vertical scaling are used to achieve smaller and faster SiGe HBT devices with greatly increased current densities. Improving both the f_T and f_MAX will be a significant challenge as the collector and base dopant concentrations are increased. The increasing current densities of the SiGe HBT will put more emphasis on interconnects as a key factor in limiting transistor layout. Capacitors and inductors are two very important passives that must improve with each generation. The trend toward increasing capacitance in polysilicon-insulator-silicon (MOSCAP), polysilicon-insulator-polysilicon (Poly-Poly), and metal-insulator-metal (MIM) capacitors is discussed. The trend in VLSI interconnections toward thinner interlevel dielectrics and metallization layers is counter to the requirements of high Q inductors, potentially requiring a custom last metallization layer     

Transmission of electric power at ultra-high voltages: Current status and future prospects

The ability to transmit larger amounts of electric power over longer distances increases with the transmission voltage. Historically, this relationship--in conjunction with its associated economies of scale--provided the basic impetus for the technological drive to utilize increasingly higher voltages for the transmission of electric power: from "high voltage" (HV) transmission at 100, 138, 161, and 230 kV to "extra-high voltage" (EHV) transmission at 345, 400, 500, and 765 kV. For the past several years, research has been under way--in this country and abroad--to bring about transmission of electric power at "ultra-high voltage" (UHV), i.e., voltage in the range of 1000 to 1600 kV. This paper reviews the present status of UHV transmission research and development and discusses current prospects for the introduction of UHV technology in the commercial transmission of electric power.     

A techno-economic assessment of application-specific integrated circuits: Current status and future trends

ASIC design methodologies are assessed from the system designer's point of view by comparing the entire IC-related product cost, design schedule, functionality, and risks to that of designs containing standard devices. ASIC methodologies include programmable logic devices, gate arrays, standard cells, and full custom, all primarily in 2-µm CMOS, at production volumes of 1 to 100K units per year and at complexities of 5OO to 20 000 gates per device. It is shown that "gates per pin" is the key determinant of total IC-related cost. Products containing ASIC cost less than those containing SSI/MSI, since ASICs raise the number of gates per pin from 2 to a range of 40-200. More surprising, products using ASIC devices cost less than products containing combinations of standard LSI/VLSI and SSI/MSI, if their gates per pin is 2-3 times that of the products containing standard devices. Each design methodology has regions, or market segments, where it is competitive. But there are large regions of small cost differences between two ASIC methodologies. Currently, these regions use primarily the older methodologies, i.e., gate arrays at low production volumes and full custom at high volumes. They also provide future opportunities for standard cells. Currently, IC manufacturing cost accounts for about 15 percent of the logic-related total cost, field maintenance for 17 percent, device and system development for 11 percent, and systems related manufacturing cost for 57 percent. These percentages are expected to migrate to 17, 20, 13, and 50 percent, respectively, by 1990. Our ASIC techno-economic assessment is summarized in 27 nomograms, figures, and charts.     

Current status of laser applications in neurosurgery

Laser application in neurosurgery was slow initially but now one-fifth of the neurosurgeons in the United States use it. Lasers offer many advantages and have few drawbacks. The CO laser is widely used for ablation of tumors and the Nd: YAG laser is useful for coagulation and sutureless blood vessel anastomosis. A variety of delivery systems are available, as well as adapters for microsurgery. Certain complications have occurred with the use of the Nd:YAG laser but these can be prevented by using proper equipment and adequate training. Current research is being conducted in the tissue effects of lasers and the laser catheter approach to vascular lesions. Lasers have a definite role in the neurosurgery of the future, which will be micromanipulative, automated, and computerized. Close cooperation between engineers and surgeons will play an important role in this development.