Showing papers in "International Journal of High Speed Electronics and Systems in 1998"
TL;DR: Carbon nanotubes exhibit unusual electronic and mechanical properties which vary with subtle changes in microstructure, applied electromagnetic field and mechanical deformations, and introduction of topological defects as mentioned in this paper.
Abstract: Carbon nanotubes exhibit unusual electronic and mechanical properties which vary with subtle changes in microstructure, applied electromagnetic field and mechanical deformations, and introduction of topological defects. These novel properties offer unprecedent opportunities to study fundamental physics, fabricate advanced composition materials, and construct quantum devices at nanometer scales.
61 citations
TL;DR: In this article, an overview on very-high-speed ICs for optical fiber systems with restriction to Si-based technologies is given, where it is shown that all ICs in 10 Gb/s TDM systems can be fabricated in Si-bipolar production technologies, while for the speed-critical ICs, present SiGe laboratory technologies are required if the circuit specifications, apart from the data rate, must remain unchanged.
Abstract: This paper gives an overview on very-high-speed ICs for optical-fiber systems with restriction to Si-based technologies. As a main aim, the circuit and system designer shall get an impression what operating speeds have already been achieved and, moreover, get a feeling for potential limitations. It is shown that all ICs in 10 Gb/s TDM systems can be fabricated in Si-bipolar production technologies, while for the speed-critical ICs in 20 Gb/s systems, present SiGe laboratory technologies are required if the circuit specifications, apart from the data rate, must remain unchanged. With uncritical circuits like time-division multiplexer (MUX) and demultiplexer (DEMUX), record data rates of 60 Gb/s systems were achieved with a SiGe laboratory technology, using an adequate mounting and measuring technique. Recent measuring results even showed that all ICs in a 40 Gb/s TDM system (i.e., also the speed-critical ones) can be realized in advanced SiGe technologies. However, compared to ICs in 10 and 20 Gb/s systems, some circuit specifications must be relaxed. This is possible by the use of optical amplifiers and improved opto-electronic components as well as by system modifications, which further make possible the elimination of some of the speed-critical circuits. It should be noted that all the experimental results presented are measured on mounted chips, using conventional wire bonding, and that most of the circuits have been used in experimental TDM links.
37 citations
TL;DR: In this paper, the authors present a summary of the advances in characterization techniques allowing comprehensive study of physical processes in semiconductor lasers, including optical gain, linewidth enhancement factor, transparency wavelength, optical loss and carrier life time.
Abstract: We present a summary of the advances in characterization techniques allowing comprehensive study of physical processes in semiconductor lasers. The studies of the electrical characteristics and optical emission below threshold allow to measure the optical gain, linewidth enhancement factor, transparency wavelength, optical loss and carrier life-time. Some other parameters, such as leakage current and wavelength chirp, can only be deduced from the above threshold measurements. Measurements of the carrier temperature and carrier heating in semiconductor lasers allow to obtain important information about the devices performance at high injection current densities. Taken together, all these measurements provide critical experimental feedback in the laser design process. They also furnish essential information to guide our understanding of the microscopic physical processes determining the laser performance and our efforts to simulate those processes.
25 citations
TL;DR: In this paper, it was shown that the computational or signal processing activity is elicited from simple charge interactions between clusters which are resistively/capacitively linked by conjugated molecular wires or ribbons, which can function as Boolean logic circuits, associative memory, image processors, and combinatorial optimizers.
Abstract: Recent advances in chemical self-assembly will soon make it possible to synthesize extremely powerful computing machinery from metallic clusters and organic molecules. These self-organized networks can function as Boolean logic circuits, associative memory, image processors, and combinatorial optimizers. Computational or signal processing activity is elicited from simple charge interactions between clusters which are resistively/capacitively linked by conjugated molecular wires or ribbons. The resulting circuits are massively parallel, fault-tolerant, ultrafast, ultradense and dissipate very little power.
18 citations
TL;DR: InP-based OEIC receivers look promising for high-speed (≥ 10 Gb/s) optical communications systems and for WDM networks because of the inherent advantages of integration, and the intrinsic speed of the devices available as mentioned in this paper.
Abstract: InP-based OEIC receivers look promising for high-speed (≥ 10 Gb/s) optical communications systems and for WDM networks because of the inherent advantages of integration, and the intrinsic speed of the devices available. This paper reviews recent developments.
15 citations
TL;DR: In this paper, a detailed account of the properties of phonons in wurtzite structures is presented, including the characteristics and interactions of dimensionally-confined longitudinal-optical (LO) and acoustic phonons.
Abstract: As device dimensions in electronic and optoelectronic devices are reduced, the characteristics and interactions of dimensionally-confined longitudinal-optical (LO) and acoustic phonons deviate substantially from those of bulk semiconductors. Furthermore, as wurtzite materials are applied increasingly in electronic and optoelectronic devices it becomes more important to understand the phonon modes in such systems. This account emphasizes the properties of bulk optical phonons in wurtzite structures, the properties of LO-phonon modes and acoustic-phonon modes arising in polar-semiconductor quantum wells, superlattices, quantum wires and quantum dots, with a variety of cross sectional geometries and, lastly, the properties of optical phonons in wurtzite materials as predicted by the dielectric continuum model. Emphasis is placed on the dielectric continuum and elastic continuum models of bulk, confined and interface phonons. This article emphasizes device applications of confined phonons in GaAs-based systems and provides a brief discussion of carrier-LO-phonon interactions in bulk wurtzite structures. This account also includes discussions on the use of metal-semiconductor heterointerfaces to reduce scattering and on the role of phonons in Frohlich, deformation and piezoelectric interactions in electronic and optoelectronic structures; specific device applications high-lighted here include quantum cascade lasers, mesoscopic devices, thermoelectric devices and optically-pumped resonant intersubband lasers.
14 citations
TL;DR: The main topic of the application section is the relation between the Toolkit configuration and the computation structure of these applications, and the conclusions related to the hardware and software as well as to the techniques for applying the system.
Abstract: The Supercomputer Toolkit is a family of hardware and software modules from which high-performance special-purpose computers for scientific/engineering use can be easily constructed and programmed The hardware modules include processors, memory, I/O devices and communication devices The software modules include an operating system, compilers, debuggers, simulators, scientific libraries, and high-level front ends When faced with a suitable problem, the engineer/scientist connects the modules by means of static-interconnect technology and constructs a problem-specific parallel computation network The network is loaded from a workstation that serves as a host When the program is run, results are collected and displayed by the host The host handles files, does compilation, etc The computation network, the Toolkit, does the heavy computation In addition to high performance, the advantage of the Toolkit is its low cost which makes it potentially affordable by small groups as their main number crunching computer This paper is concerned with the Toolkit version built at the Technion, which is a second generation of the MIT version1 The paper briefly describes the hardware and software of this new version and its application to elastic-plastic flow, weather prediction and the simulation of electronic circuits The main topic of the application section is the relation between the Toolkit configuration and the computation structure of these applications The paper discusses conclusions related to the hardware and software as well as to the techniques for applying the system
12 citations
TL;DR: In this paper, physics-based analytical DC models for amorphous silicon (a-Si), polysilicon (poly-Si) and organic thin film transistors (TFTs), developed for the design of novel ultra high-resolution, large area displays using advanced short-channel TFTs, are presented.
Abstract: We review recent physics-based, analytical DC models for amorphous silicon (a-Si), polysilicon (poly-Si), and organic thin film transistors (TFTs), developed for the design of novel ultra high-resolution, large area displays using advanced short-channel TFTs. In particular, we emphasize the modeling issues related to the main short-channel effects, such as self-heating (a-Si TFTs) and kink effect (a-Si and poly-Si TFTs), which are present in modern TFTs. The models have been proved to accurately reproduce the DC characteristics of a-Si:H with gate lengths down to 4 μm and poly-Si TFTs with gate lengths down to 2 μm. Because the scalability of the models and the use of continuous expressions for describing the characteristics in all operating regimes, the models are suitable for implementation in circuit simulators such as SPICE.
12 citations
TL;DR: In this paper, the authors consider the properties of 2D electrons in silicon devices, where plasma effects might also play an important role in deep submicron MOSFETs.
Abstract: In deep submicron silicon MOSFETs, GaAs-based HEMTs, and in new emerging heterostructure systems, such as AlGaN/GaN, electrons forming a two-dimensional (2D) conducting channel exhibit new interesting effects that might find important device applications. Some of these effects are related to the space dependence of the electron mass. Other effects are linked to a large sheet electron concentration, when electrons behave not as a 2D gas but rather as a 2D electron electron fluid. We consider plasma effects in this fluid and discuss plasma wave electronic devices that rely on these effects. We also discuss the properties of 2D electrons in silicon devices, where plasma effects might also play an important role in deep submicron MOSFETs.
11 citations
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TL;DR: The BSIM3v3 model as discussed by the authors is a physics-based model that is accurate, smooth, continuous, scalable, predictive and computationally robust over different regions of operation and a wide geometry range.
Abstract: The BSIM3v3 compact MOSFET model is reviewed. It is a physics-based model that is accurate, smooth, continuous, scalable, predictive and computationally robust over different regions of operation and a wide geometry range. BSIM3v3 considers all major physical effects in deep submicron MOSFETs, making it a good base for future sub-0.1m device models and for statistical circuit designs. A key feature of the model lies in its thorough, accurate and functional mathematical representation of MOS device physics, which has made BSIM3v3 selected by an international consortium of semiconductor companies as the first industry standard MOSFET model.
9 citations
TL;DR: In this paper, the theory of Bloch electron dynamics in spatially homogeneous electric fields of arbitrary strength and time dependence is presented, where the electric field is described through the use of the vector potential, and the instantaneous eigenstates of the Hamiltonian are used as basis stated to depict the Bloch dynamics and quantum properties.
Abstract: The theory of Bloch electron dynamics in spatially homogeneous electric fields of arbitrary strength and time dependence is presented. In the formalism, the electric field is described through the use of the vector potential, and the instantaneous eigenstates of the Hamiltonian are used as basis stated to depict the Bloch dynamics and quantum properties. This approach leads to a natural indication of high- and low-filed limits, and allows for the inclusion of general band-structure effects and multiband coupling in the quantum dynamics. A variety of dc electric field effects, such as Bloch oscillations, Zener tunneling, and localization, and ac electric field effects, such as interband absorption, and phonon-assisted transport, will be discussed.
TL;DR: Novel nanoelectronic architecture paradigms based on cells composed of coupled quantum-dots arranged in suitably designed cellular arrays are discussed and a network-theoretic description of such Quantum-Dot Nonlinear Networks (Q–CNN) is outlined.
Abstract: We discuss novel nanoelectronic architecture paradigms based on cells composed of coupled quantum-dots. These ideas of a transistor-less approach represent a radical departure from conventional technology. We utilize a strategy which exploits the physical interactions between quantum-dots arranged in suitably designed cellular arrays. Boolean logic functions may be implemented in specific arrays of cells representing binary information, the so-called Quantum-Dot Cellular Automata (QCA). Cells may also be viewed as carrying analog information and we outline a network-theoretic description of such Quantum-Dot Nonlinear Networks (Q–CNN). In addition, we discuss possible realizations of these structures in a variety of semiconductor systems (including GaAs/AlGaAs, Si/SiGe, and Si/SiO2), rings of metallic tunnel junctions, and candidates for molecular implementations.
TL;DR: Schrodinger Equation and (based) Monte Carlo (SEMC) as mentioned in this paper is a simulation method designed to bridge the gap from quantum to classical transport, which allows carriers to be followed through a sequence of stochastically sampled scattering events.
Abstract: Schrodinger Equation and (based) Monte Carlo (SEMC), a simulation method designed to bridge the gap from quantum to classical transport, is described. This method provides a non-perturbative, current conserving quantum mechanical treatment of carriers, phonons, and their coupling, yet the SEMC algorithm is analogous to and compatible with that of semiclassical Monte Carlo (SMC). Indeed, SEMC allows carriers to be followed through a sequence of stochastically sampled scattering events. Phase breaking and energy dissipation for charge carriers within the Schrodinger-equation-based method are modeled via the exchange of probability among oscillator degrees of freedom, mimicing the true process of carrier-phonon scattering. Carrier-phonon coupling potentials for SEMC are obtained by Monte Carlo sampling of (the spatial correlation functions of) the true carrier-phonon coupling potentials. Illustrative results demonstrate SEMC's ability to provide both physically and quantitatively accurate modeling of, in particular, long-range polar-optical scattering, and to completely bridge the gap between phase-coherent and phase-incoherent transport.
TL;DR: The technical issues that bear on high-speed circuits in this context, as well as the device technologies available for these circuits in both laboratory and commercial processes are summarized.
Abstract: Recent increase in the demand for bandwidth in the telecommunications network has stimulated both research and commercial activity in high-speed electronics. This paper summarizes the technical issues that bear on high-speed circuits in this context, as well as the device technologies available for these circuits in both laboratory and commercial processes. Finally a tutorial treatment is given of the main design requirements pertinent to circuits required for lightwave systems.
TL;DR: In this paper, the authors developed a chip set for 20-40 Gbit/s fiber-optical digital transmission systems using 0.2 and 0.3 μm AlGaAs/GaA/AlGaAs quantum well HEMT technology.
Abstract: Using our 0.2 and 0.3 μm AlGaAs/GaAs/AlGaAs quantum well HEMT technology, we have developed a chip set for 20–40 Gbit/s fiber-optical digital transmission systems. In this paper we describe nine analog and digital receiver ICs: a 22 GHz high-gain transimpedance amplifier, a 20 Gbit/s OEIC front-end optical receiver, a 25 Gbit/s automatic-gain-control amplifier, a limiting amplifier with a differential gain of 26 dB and a bandwidth of 27.7 GHz, a 20–40 Gbit/s clock recovery, a 20 Gbit/s low-power Master-Slave-D-Flipflop with 24 mW power dissipation, a parallel data decision and a 1:4 demultiplexer, both for bit rates of 40 Gbit/s, and a 30 GHz static frequency divider, respectively. All chips were characterized on wafers with 50 Ω coplanar test probes.
TL;DR: In this article, it was shown that dielectric breakdowns can occur under fabrication conditions without using a controlled forming process, which is potentially important for silicon based quantum devices as well as serving as an SOI (silicon on insulator).
Abstract: Quantum mechanical devices utilize the wave nature of electrons for their operations whenever the electron mean-free-path exceeds the appropriate dimensions of the device structure. Some of the issues such as the tunneling time, the reduction of the dielectric constant and the drastic increase in the binding energy of dopants are discussed. Lacking an appropriate barrier for silicon, the majority of quantum devices are fabricated with compound semiconductors. In the past several years, certain schemes appeared, such as the resonant tunneling via nanoscale silicon particles imbedded in an oxide matrix, and the superlattice barrier for silicon consisting of several periods of Si/O. There appears some doubt about the tunneling nature of the former, and the possiblity of dielectric breakdowns. This article aims to show that dielectric breakdowns can occur under fabrication conditions without using a controlled forming process. The latter results in epitaxially grown silicon beyond the superlattice barrier region, free of stacking fault defects, and thus is potentially important for silicon based quantum devices as well as serving as an SOI (silicon on insulator), without ion-implantation damage and oxygen inclusion. The replacement of SOI by the epitaxially grown Si/O superlattice barrier should promote the effort in high speed and low power MOSFET devices.
TL;DR: New types of a data selector and flip-flops are devised, which are key elements in performing high-speed digital functions in front-end transmitter/receiver systems, and are a potential candidate for 20- to 40-Gbit/s class applications.
Abstract: This paper describes recent advances in high-speed digital IC design technologies based on GaAs MESFETs for future high-speed optical communications systems. We devised new types of a data selector and flip-flops, which are key elements in performing high-speed digital functions (signal multiplexing, decision, demultiplexing, and frequency conversion) in front-end transmitter/receiver systems. Incorporating these circuit design technologies with state-of-the-art 0.12 μm gate-length GaAs MESFET process, we developed a DC-to-44-Gbit/s 2:1 data multiplexer IC, a DC-to 22-Gbit/s static decision IC, and a 20-to-40-Gbit/s dynamic decision IC. The fabricated ICs demonstrated record speed performances for GaAs MESFETs. Although further operating speed margin is still required, the GaAs MESFET is a potential candidate for 20- to 40-Gbit/s class applications.
TL;DR: In this paper, the role of lateral ambipolar drift-diffusion of carriers in either hindering or, potentially, in enhancing the provision of gain to the desired optical mode is discussed.
Abstract: Since its invention in the 60's, the semiconductor laser has relied on vertical injection of electrons and holes in order to pump the active region to inversion. While many aspects of semiconductor laser development have seen tremendous innovation and marked progress, this vertical injection scheme has remained unchanged. In contrast, the electronic transistor has evolved from the early dominance of vertical injection to today's largely lateral injection CMOS platform, which yielded new performance, functionality, and integrability and enabled the astonishingly successful integrated circuit revolution. The lateral current injection laser offers advantages which go far beyond optoelectronic integrability: it enables new functionalities, post-fabrication processing and engineering, and in some aspects of normal operation it can lead to greatly improved performances. To realize its full potential, this new class of semiconductor lasers deserves the same attention and the intensive iterations of efforts in theory, design, fabrication, and experimental probing as its vertical cousin has been received. We introduce a first-principles, combined theoretical-experimental approach to the exploration of the LCI laser. It reveals the role of lateral ambipolar drift-diffusion of carriers in either hindering or, potentially, in enhancing the provision of gain to the desired optical mode; of two-dimensional bandstructure engineering of the injection path and active region to achieve low differential resistance and efficient modal gain provision; of selective formation and lateral positioning of heterojunction in enabling high-efficiency device operation; and of adiabatic injection of electrons and holes across diffusively-graded heterojunctions in facilitating carrier capture into 2D quantum well states. Our results point to the tremendous promise of lasers based on lateral injection of current in enabling vertical cavity lasers with vastly increased performance and functional diversity; multi-terminal devices such as lasers with capacitive gain and wave-length tunability; high-speed directly-modulated lasers with reduced chirp; and functional devices with directly integrated high-speed longitudinal modulation.
TL;DR: In this article, a simplified model of the quantum cascade laser is presented which provides a good estimate of major device parameters and illustrates the principles of operation and physical processes, and device schemes of other intersubband lasers such as step quantum wells are also presented and analyzed.
Abstract: This chapter/paper provides an overview of quantum well intersubband lasers including quantum cascade and step quantum well lasers. A simplified model of the quantum cascade laser is presented which provides a good estimate of major device parameters and illustrates the principles of operation and physical processes. Device schemes of other intersubband lasers such as step quantum wells are also presented and analyzed.
TL;DR: Averin and Likharev as discussed by the authors showed that with the use of ultrasmall tunnel junctions a time correlation of electron flow through a junction could be observed, and permit the measurement of the effect of a net charge of less than one electron on the junction.
Abstract: In the mid 1980s Averin and Likharev predicted that with the use of ultrasmall tunnel junctions a time correlation of electron flow through a junction could be observed, and permit the measurement of the effect of a net charge of less than one electron on the junction. Both effects were soon experimentally verified, and since that time there has been an explosion of work in the filed of single electron devices. This chapter reviews the fundamental concepts behind the operation of such devices. it then describes some of the single electron effects studied in semiconductors. Superconducting devices are then constrasted to the semiconductor and the normal metal single electron devices. The details of some current applications are described, and a thumbnail sketch of current fabrication methods is given.
TL;DR: In this paper, the current status of InP-based lightwave communication ICs in terms of device, circuit, and packaging technologies is reviewed and a successful 40Gbit/s, 300-km optical fiber transmission using InP HFET ICs demonstrates the feasibility of the ICs.
Abstract: High-speed integrated circuits (ICs) are essential for expanding the capacity of light-wave communications. InP-based heterostructure field effect transistors (HFETs) and heterojunction bipolar transistors (HBTs) are very promising for producing high-speed digital and analog ICs. This paper reviews the current status of InP-based lightwave communication ICs in terms of device, circuit, and packaging technologies. A successful 40-Gbit/s, 300-km optical fiber transmission using InP HFET ICs demonstrates the feasibility of the ICs. Furthermore, we estimate future IC performance based on the relationship between electron device figures-of-merit and IC speed. To keep up with the performance trend, technological problems, like inter- and intra-chip interconnections, have to be solved.
TL;DR: In this paper, the state-of-the-art and fundamental issues of InGaN-based light-emitting diodes and laser diode design are discussed, and the correlation of photoluminescence and optical pumping has shown that band-to-band or shallow donor-related bandtail to valence band transition is the necessary mechanism of lasing in GaN.
Abstract: We discuss optical properties of III-Nitride materials and structures. These properties are critical for the development of III-Nitride-based light-emitting diodes and laser diodes. Minority carrier diffusion length in GaN has been determined to be ~ 0.1 μm. The properties of lasing in GaN have been studied using optical pumping. The red shift of emission peak observed in stimulated emission of GaN has been modeled and attributed to many-body interactions at high excitation. The correlation of photoluminescence and optical pumping has shown that band-to-band, or shallow donor-related bandtail to valence band transition is the necessary mechanism of lasing in GaN. This work showed that the thermal instability of InGaN at growth temperature is of main concern in the fabrication of InGaN-based MQW laser diode structures. Photoluminescence has shown that the InGaN composition is very sensitive to the growth temperature. Therefore InGaN growth temperature should be strictly controlled during InGaN-based MQW growth. This work discovered that proper annealing of Si-doping of InGaN/GaN MQW structures that are properly annealed could reduce the lasing threshold and improve the slope efficiency. Over-annealing of these MQWs can lead to thermal degradation of the active layer. Si-doping in over-annealed MQW structure further degrades its quality. The degradation has been attributed to the increase of defects and/or nonuniform local potential formation. P-type doping on the top of InGaN/GaN could also lead to the formation of compensation layer which also degrades laser diode performances. Optical confinement and carrier confinement in InGaN-based laser diode structures are evaluated for optimum laser diode design. The state-of-the-art and fundamental issues of InGaN-based light-emitting diodes and laser diodes are discussed.
TL;DR: In this paper, the authors describe the procedures by which intersubband quantum-well semiconductor lasers (or detectores) may be designed using these methodologies using quantum state engineering based on electromagnetic analogies.
Abstract: The design of semiconductor intersubband lasers using quantum state engineering based on electromagnetic analogies is a relatively new area. There has been little systematic effort in this direction as yet. The use of these analogies allows laser researchers to apply tools and methodologies found in the mature field of electromagnetic optics. The purpose of this paper is to describe the procedures by which intersubband quantum-well semiconductor lasers (or detectores) may be designed using these methodologies.
TL;DR: In this paper, the authors address the issues associated with physics and technology of diode lasers based on self-organized quantum dots (QDs). And theoretically predicted advantages of a QD array as the active region of a semiconductor laser and basic principles of QD formation using self-organization phenomena are discussed.
Abstract: This paper addresses the issues associated with physics and technology of diode lasers based on self-organized quantum dots (QDs). Theoretically predicted advantages of a QD array as the active region of a semiconductor laser and basic principles of QD formation using self-organization phenomena are discussed. Special attention is paid to relationship between structural and electronic properties of QDs and laser characteristics. Recent ahcievements in controlling these parameters including the effects of vertical stacking, changing the matrix bandgap and the surface density of QDs are reviewed. The threshold and power characteristics of the state-of-the-art QD lasers are demonstrated.
TL;DR: In this paper, the concept of transferred-substrate HBTs fabrication process in the AlInAs/GaInAs material system is presented, followed by DC and RF performance A demonstration IC is shown along with some integrated circuits in development.
Abstract: Transferred-substrate heterojunction bipolar transistors (HBTs) have demonstrated very high bandwidths and are potential candidates for very high speed integrated circuit (IC) applications The transferred-substrate process permits fabrication of narrow and aligned emitter-base and collector-base junctions, reducing the collector-base capacitance and increasing the device fmax Unlike conventional double-mesa HBTs, transferred-substrate HBTs can be scaled to submicron dimensions with a consequent increase in bandwidth This paper introduces the concept of transferred-substrate HBTs Fabrication process in the AlInAs/GaInAs material system is presented, followed by DC and RF performance A demonstration IC is shown along with some integrated circuits in development
TL;DR: In this paper, the authors describe experimental ultra-high-speed HBT circuits for lightwave communications applications, such as DC-26 GHz VGAs, DC-25 GHz transimpedance amplifiers and 40 Gb/s differentiate-and-rectify timing recovery circuits, for use in such systems using a manufacturable hybrid digital/microwave HBT process.
Abstract: We describe experimental ultra-high-speed HBT circuits for lightwave communications applications. High speed circuits such as multiplexer/demultiplexers, variable gain amplifiers, (VGAs), and transimpedance amplifiers operating at high bit rates (>30 Gb/s) are required for the realization of high-performance lightwave systems using TDM or WDM. We have demonstrated 40 Gb/s 4:1 multiplexer, >30 Gb/s 1:4 demultiplexers, DC-26 GHz VGAs, DC-25 GHz transimpedance amplifiers, 30 Gb/s data and clock regenerators, 40 Gb/s differentiate-and-rectify timing recovery circuits, and 40 Gb/s delay-and-multiply timing recovery circuits, for use in such systems using a manufacturable hybrid digital/microwave HBT process.
TL;DR: In this paper, the authors present a 10 Gb/s crosspoint switch implemented in GaAlAs/GaAs-HBT technology, including details of design, packaging, testing methodology, and performance results.
Abstract: Technology and performance of electronic crosspoint switches with data rates above 1 Gb/s/channel are reviewed. Switch applications and architectures are described, as well as the principal problems in achieving low output jitter. Recent results for different IC technologies are summarized. As a particular example, a 10 Gb/s crosspoint switch implemented in GaAlAs/GaAs-HBT technology is described, including details of design, packaging, testing methodology, and performance results.
TL;DR: Analytical, physics-based modeling incorporating the important effects present in modern day devices, including deep sub-micrometer devices are emphasized, in order to accurately describe and predict both stationary and dynamic device behavior.
Abstract: We review recent advances in the modeling of novel and advanced semiconductor devices, including state-of-the-art MESFET and HFETs, heterodimensional FETs, resonant tunneling devices, and wide-bandgap semiconductor transistors. We emphasize analytical, physics-based modeling incorporating the important effects present in modern day devices, including deep sub-micrometer devices. Such an approach is needed in order to accurately describe and predict both stationary and dynamic device behavior and to make the models suitable for implementation in advanced computer aided design tool including circuit simulators such as SPICE.
TL;DR: In this paper, the authors describe the operation of an optically pumped "quantum fountain laser" made of asymmetric coupled quantum well structures, a FIR quantum wire laser pumped by optic phonons and an electrically tunable, mode-locked FIR quantum dot laser.
Abstract: Advanced concepts in intersubband optical emission for mid-infrared (MIR) and far-infrared (FIR) lasers in nanostructures are presented. Electronic tunability of low dimensional systems, and new simulation techniques are implemented for engineering electron scattering time with phonons and improving laser performances. We successively describe the operation of an optically pumped "quantum fountain laser" made of asymmetric coupled quantum well structures, a FIR quantum wire laser pumped by optic phonons and an electrically tunable, mode locked FIR quantum dot laser.
TL;DR: In this paper, a Si preamplifier with 300-Ω transimpedance was designed by focusing on attaining low transimpingance fluctuation in the frequency response despite bias variation caused by the photo current.
Abstract: Design considerations concerning Si preamplifiers for 10-Gb/s optical transmission systems are discussed. A preamplifier with 300-Ω transimpedance was designed by focusing on attaining low transimpedance fluctuation in the frequency response despite bias variation caused by the photo current. To ensure good design accuracy, we optimized the current density of the transistor and the open-loop voltage gain using measured results to obtain the desired bandwidth. We also developed a low-loss pad structure that has U-grooves to improve the bandwidth. The U-grooves increase the pad parasitic resistance and reduce signal-loss from pad to Si substrate. A preamplifier IC fabricated using a Si bipolar technology with fT of 35-GHz provided a bandwidth of 10.2 GHz, transimpedance fluctuation within 0.5 dB, an input dynamic range of up to 1.6 mAp-p, and a low averaged input noise current density of 11.5 .