Optical communications—A decade of preparations

This paper, an introduction to this first Special Issue on Optical Communications, follows some of the arguments that have prevailed for and against optics as a viable communications medium for terrestrial and space applications, and assesses the present state of the art of optics devices, systems, and theory, based on discussions with scientists and engineers who have been specializing in the optical field. It also attempts in a small way to give some appreciation of the special problems the traditional communications engineer faces in readjusting his thinking and his "physical intuition" in going from the world of electrons to the world of photons.     

A Cr—Ag—Au metalization system

A comprehensive study of a Cr-Ag-Au metalization system, as well as a comparison with an aluminum system, is described. The Cr-Ag-Au metalization system, which can be deposited in a conventional evaporator with relatively little increase in processing complexity, has the desirable characteristics of aluminum metalization. It can be patterned more easily than equivalent thicknesses of aluminum. The Cr-Ag-Au has excellent storage characteristics at 300°C and has a much longer mean time to failure than does aluminum under high current density-high temperature stress. In addition, measurements show that with the use of an enhancement diffusion the Cr-Ag-Au produces as good as or better contact to p- and n-type silicon than does aluminum. Finally, the absence of significant metalization-oxide interaction makes Cr-Ag-Au useful for MOS devices and the ease with which contact is made between layers of this metalization indicates a number of applications for Cr-Ag-Au in multilayered devices.     

A Facile In Situ Surface-Functionalization Approach to Scalable Laminated High-Temperature Polymer Dielectrics with Ultrahigh Capacitive Performance

High-temperature dielectric materials for capacitive energy storage are in urgent demand for modern power electronic and electrical systems. However, the drastically degraded energy storage capabilities owing to the inevitable conduction loss severely limit the utility of dielectric polymers at elevated temperatures. Herein, a new approach based on the in situ preparation of oxides onto polyimide (PI) films to high-temperature laminated polymer dielectrics is described. As confirmed by computational simulations, the charge injection at the electrode/dielectric interface and electrical conduction in dielectric films are substantially depressed via engineering the in situ prepared oxide layer in the laminated composites. Consequently, ultrahigh dielectric energy densities and high efficiencies are simultaneously achieved at elevated temperatures. Especially, an excellent energy density of 1.59 J cm⁻³ at a charge–discharge efficiency of above 90% has been achieved at 200 °C, outperforming the current dielectric polymers and composites. Together with its excellent discharging capability and cyclic reliability, the laminate-structured film is demonstrated to be a promising class of polymer dielectrics for high-power energy storage capacitors operating at elevated temperatures. The facile preparation method reported herein is readily adaptable to a variety of polymer thin films for energy applications under extreme environments.     

A lateral metal—insulator—p-Si tunnel transistor

We report the fabrication of a lateral MIS tunnel transistor whose emitter and collector are Al/SiO2/p-Si tunnel junctions. All processing is carried out at room temperature except for the growth of the passivating field oxide. The small signal common emitter current gain is 20. Two coupled gain mechanisms exist for such a lateral MIS tunnel transistor. The first mechanism relies on a high minority-carrier injection ratio of the emitter junction. Second, the minority carriers injected into the reverse-biased collector junction may produce additional gain through multiplication of majority-carrier current. Lateral MIS tunnel transistors on n-Si make use of the second mechanism. Our device takes advantage of the high minority-carrier injection ratio achievable with Al/SiO2/p-Si tunnel junctions.     

Electrophotography—A review

This review is concerned primarily with the electrophotographic systems currently in use, i.e., the electrodeless stored energy systems. First, the history of reproduction is traced from printing, through wet- and dry-chemical photography, to electrophotographic systems. The electrodeless system is defined and described in terms of the processing. Then, the light sensitive materials and processing are examined, and the characteristics of the material comprising the electrophotographic layer are related to the operational steps of charging and exposure. The principal development materials, dry powder, and liquid toners, are described on an electrochemical basis, and the toning mechanisms are reviewed. Finally, the principal applications and future trends of electrophotographic systems are outlined.     

A low-voltage alterable EEPROM with metal—oxide-nitride—oxide—semiconductor (MONOS) structures

Theoretical and experimental investigations to obtain lower voltage electrically erasable and programmable ROM's (EEPROM's) than conventional devices have been performed. The scaled-down metal-oxide-nitride-oxide-semiconductor (MONOS) structure is proposed to realize an extremely low-voltage programmable device. The proposed scaled-down MONOS devices enjoy several advantages over MNOS devices, e.g., enlargement of the memory window, elimination of degradation phenomena, and drastic improvement in device yield. Low-voltage operation with ± 6-V supplies is demonstrated by the fabricated scaled-down MONOS transistors.     

流水行云:支持可扩展的并行分布式流处理系统

数据流处理系统,无论是集中式还是分布式,都需要克服单点瓶颈问题.不仅如此,如果数据流处理系统是静态配置的,那么还会出现处理节点供给不足或者过剩的情况,为此本文提出了一种支持可扩展的并行分布式数据流处理系统-流水行云,该系统根据有状态算子将查询拓扑划分为并行处理的子查询,并且通过有状态算子的分发器和收集器实现了数据流的保序,同时最大化减少并行处理的通信开销,不仅如此,结合负载均衡和重配置的可扩展技术使得该系统能够根据输入负载动态调整处理节点的负载和个数.60个节点组成的集群的实验证明了该系统的可扩展能力.     

MERIT: A Scalable Approach for Protocol Assessment

MERIT is a framework that can be used to assess routing protocols in mobile ad hoc networks (manets). It uses the novel concept of a shortest mobile path (SMP) in a mobile graph, a generalization of the shortest path problem for mobile environments. As a measure for routing protocol assessment, we propose the mean ratio of the cost of the route used by a protocol to the cost of the optimal mobile path for the same network history. The cost reflects that the route used in a session can change over time because of network dynamics such as topology changes. The aim is for the ratio to be an abstract, inherent measure of the protocol that is as implementation-independent as possible. The MERIT spectrum, which is the ratio expressed as the function of some parameters of interest, is a characterization of protocol effectiveness. MERIT, for MEan Real vs. Ideal cosT, provides a scalable assessment framework: rather than comparing performance measures of different protocols directly, we compare a protocol to the optimal solution. That is, rather than forcing the comparison to be in the same system, it is done once for each protocol in its own environment. Furthermore, we show that there is an efficient algorithm to solve the underlying SMP problem for important cases, making the approach practically feasible. We also investigate generalizations of and extensions within the MERIT framework. We show that the MERIT framework is rich, with much wider generality and potential applicability than assessing routing protocols.     

High-performance MOSFET—A correspondence

The limiting factors in the performance of power MOSFET's are discussed in response to a previously published paper [1]. The limitations of diffused guard rings, use of SIPOS, RONand switching response are noted. Calculated RONand measured data are presented for VMOS and DMOS designs, which indicate the advantage of DMOS.     

A two-dimensional model for the lateral p—n—p transistor

A two-dimensional solution of the continuity equation in the base of the lateral p-n-p transistor, including interactions with the substrate and subdiffused layer, is presented for dc excitation. This method is extended to the case of steady-state sinusoidal excitation. Computed and measured results are presented for the frequency dependence of the Short-circuit small-signal current transfer ratios, and comparison of these shows reasonable agreement over the full range of measurements. An approximate equivalent circuit derived from a single-pole fit to the frequency response of short-circuit admittance parameters is inferred to be valid Up to a few megahertz for the device considered.     

Integrated electronics—A perspective

Integrated electronics promises to increase both the rate of change within the electronics industry and the pervasiveness of electronics as a whole, making it possible to remove very fundamental and interrelated limitations to applying the knowledge and tools of electronics, the most harassing of which have been reliability, cost, complexity, and that imposed by the specialized character of and relative sophistication of the science, engineering, and art of electronics. Evaluating the history, current status and the likely future of integrated electronics, it seems now highly probable that this new technology may introduce a terminal phase in which electronics will pervade all segments of our society to which it has pertinence. Basic requirements to ensure this appear to be 1) A relatively concentrated, highly-automated industrial complex to supply integrated circuitry and closely related compatible discrete componentry and 2) Establishment by this integrated-circuits industry of a common language for the input and output parameters which specifies its products, ultimately making it possible for members of other disciplines and professions to utilize, without themselves being electronics specialists, the knowledge, tools, and skills of electronics for the benefit of all of society.     

A high-performance 2—18.5-GHz distributed amplifier—Theory and experiment

A high-performance 2-18.5-GHz monolithic GaAs MESFET distributed amplifier has been designed and fabricated. The distributed amplifier is analyzed theoretically using a normalized transmission matrix approach, and a closed-form gain equation is presented for the MMIC m-derived drain-line case. Theoretical predictions are compared to measured results and more complicated CAD models. The measured small, signal gain is typically 8.0±0.40 dB from 2-18.5 GHz at standard bias. Typical input return loss is greater than 12 dB, and the output return loss is greater than 15 dB. The saturated output power is in excess of 23 dBm over most of the band, and the noise figure is less than 7.5 dB.     

INTELSAT VI—A continuing evolution

In early 1982, the International Telecommunications Satellite Organization (INTELSAT) awarded a contract to the Hughes Aircraft Company for a new generation of communications satellites. The INTELSAT VI satellites are the largest, most sophisticated commercial communications satellites ever built. Their major technological challenges include a six-fold reuse of the 6/4-GHz frequency spectrum and the introduction of satellite-switched TDMA. The INTELSAT VI satellites are designed to become the backbone of the INTELSAT system in the late 1980s and early 1990s.     

A new bipolar transistor—GAT

A new bipolar transistor named Gate Associated Transistor (GAT) was proposed and the operating mechanisms were verified. The structure of the GAT has a unique base region consisting of an FET merged into the base of a standard bipolar transistor. The operating mechanisms and characteristics of the GAT were investigated and compared with those of standard power transistors. The most outstanding feature of the GAT was a large area for safe operation.     

Acousto-optics—A review of fundamentals

The paper first reviews the historical development of acousto-optics and its applications. Following this, a heuristic explanation of acousto-optic effects is presented, with the emphasis on the plane wave model of interaction. Finally, there is a discussion of some basic configurations of relevance to signal processing.     

The factorization problem—A survey

The problem of factoring a positive Hermitian operator into the product of a causal operator and its adjoint is reviewed. Three classes of factorization are studied, miniphase factorization, regular factorization, and special factorzation. The former always exists, and a complete representation thereof is obtained in terms of the properties of reproducing kernel spaces. The regular factorization does not exist, in general, and its existence theroy is shown to be equivalent to the unitary equivalence problem of classical operator theory. Finally, an existence and uniqueness theorem for special factors is formulated in terms of certain Cauchy integrals and is shown to be closely related to Wiener-Hopf theory.     

Spectrum analysis—A modern perspective

A summary of many of the new techniques developed in the last two decades for spectrum analysis of discrete time series is presented in this tutorial. An examination of the underlying time series model assumed by each technique serves as the common basis for understanding the differences among the various spectrum analysis approaches. Techniques discussed include the classical periodogram, classical Blackman-Tukey, autoregressive (maximum entropy), moving average, autotegressive-moving average, maximum likelihood, Prony, and Pisarenko methods. A summary table in the text provides a concise overview for all methods, including key references and appropriate equations for computation of each spectral estimate.     

Gridistor—A new field-effect device

This article concerns a new category of field effect transistors currently being developed which are derived from the Tecnetron (known as the Fieldtron in the U.S.A.) and which use the principal of centripetal striction and have a multichannel structure. By this development it is intended that the advantages of bipolar and field effect transistors be combined insofar as this is possible. In the theoretical part of the article the peculiarities of centripetal striction are discussed. It is shown that since the multichannel structure of the Gridistor removes the limitations arising from the restriction on the degrees of freedom, it eliminates the disadvantages of centripetal striction while retaining its advantages. The various geometries of the Gridistor and the techniques for realizing them are then described with particular attention to their remarkable suitability for integrated circuits. The results obtained are then given briefly and prospects for the future are outlined.