Testbed for a scalable terabit optical local area network

The design of a fiber-optic local area network (LAN) demonstration system is described. A complete LAN system would consist of an array of 16 personal computers (PC's), where each PC has a network interface card (NIC) with a parallel fiber-optic datalink to a centralized optoelectronic switch core. The centralized core switches the data generated by 16 NIC's, up to 128 Gbit/s of bandwidth. The demonstrator is designed to scale to terabits of bandwidth by use of an emerging optoelectronic technology, i.e., integrated complementary metal-oxide semiconductor (CMOS) substrates with vertical-cavity surface-emitting laser (VCSEL) and photodetector optical input and output. A subset of the complete system was constructed and is operational. A prototype NIC card, with Motorola Optobus VCSEL transceivers for the optical datalinks, was constructed and is described. A prototype high-speed bipolar switch core, with statically configurable electrical positive-emitter coupled-logic 16 x 16 crossbar switches, CMOS field-programmable gate arrays, and Motorola Optobus transceivers, was constructed and is described. We successfully demonstrated the transmission of high-speed packetized data from one NIC card, through 10 m of parallel fiber ribbon and the centralized switch core, and back to the NIC. We summarize our experiences on the design and testing of our first demonstration system and our development toward a terabit switch core.     

SOI光电子集成

SOI（Silicon-on-Insulator)光电子集成已成为十分引人注目的研究课题，其工艺与CMOS工艺完全兼容，可以实现低成本的SOI基整片集成光电子回路。本文综述了近几年来SOI集成光电子器件的发展以及一些最新的研究进展，着重分析几种最新型光无源器件的工作原理和结构，包括SOI光波导、SOI光波导耦合器、SOI光波导开关、相位阵列波导光栅（PAWG）、基于SOI的光探测器等，并介绍了中国科学院半导体所集成光电子国家重点实验室的研究进展。     

VCSEL-array-based angle-multiplexed optoelectronic crossbar interconnects

A large crossbar switch, which is a desirable building block for any low-latency interconnect network, is difficult to implement because of many practical problems associated with digital electronics. We propose a new method for implementing a large optoelectronic crossbar interconnect to take advantage of a unique principle of optics. Based on an emerging vertical-cavity surface-emitting laser (VCSEL) technology, a passive angle-multiplexed beam-steering architecture is proposed as a key component of the optoelectronic crossbar. Various optical system parameters are evaluated. Because there is no optical fan-out power loss, the interconnect capacity of the proposed system is determined by the diffraction-limited receiver power cutoff, and therefore interconnection of more than 1000 nodes with a per node bandwidth of 1 GHz is possible with today's technology. A 64-element VCSEL-array-based proof-of-principle optical system for studying the interconnect scalability has been built. Details of the features of the proposed system, its advantages and limitations, demonstration experimental results, and their analyses are presented.     

A microprocessor based electromagnetic field analysis system

The construction of an interactive finite element analysis system is described. First the components of the finite element software are considered. Second, the advantages of dedicated single user workstations are discussed. An example is given of a complete system implemented on a microprocessor based workstation.     

Optical bandwidth in coupling: the multicore photonic switch

In the present study, the bandwidth of a photonic switch described previously [Appl. Opt. 37,2296 (1998); 38, 3239 (1999)] is evaluated. First the optical bandwidth is evaluated for coupling between two fiber-core waveguides, in which the cores are embedded within the same cladding. Then the coupling bandwidth is determined for a fiber-core-to-slab-core waveguide, in which the cores are embedded within the same cladding. These bandwidths are then compared and contrasted with the bandwidths of the photonic switch, which consists of two fiber cores and a control waveguide. Two configurations of the photonic switch are considered: one in which the control waveguide is a fiber core and one in which the control waveguide is a slab core. For the photonic switch, the bandwidth characteristics are more complicated than for the coupled pairs, and these characteristics are discussed in detail.     

Optoelectronic Systems Based on InGaAs- Complementary-Metal-Oxide-Semiconductor Smart-Pixel Arrays and Free-Space Optical Interconnects

Free-space optical interconnects have been identified as a potentially important technology for future massively parallel-computing systems. The development of optoelectronic smart pixels based on InGaAs/AlGaAs multiple-quantum-well modulators and detectors flip-chip solder-bump bonded onto complementary-metal-oxide-semiconductor (CMOS) circuits and the design and construction of an experimental processor in which the devices are linked by free-space optical interconnects are described. For demonstrating the capabilities of the technology, a parallel data-sorting system has been identified as an effective demonstrator. By use of Batcher's bitonic sorting algorithm and exploitation of a perfect-shuffle optical interconnection, the system has the potential to perform a full sort on 1024, 16-bit words in less than 16 mus. We describe the design, testing, and characterization of the smart-pixel devices and free-space optical components. InGaAs-CMOS smart-pixel, chip-to-chip communication has been demonstrated at 50 Mbits/s. It is shown that the initial system specifications can be met by the component technologies.     

Two-moment approximations for analysing a series of automated workstations

In this research we develop two-moment approximation equations for the analysis of a series of automated workstations with infinite buffer capacity. An automated workstation is a server with deterministic processing times that experiences random operating times between failures, and then subsequent random repair times. The distribution of job inter-departure times from a workstation receiving input from an automated workstation is derived. From this distribution, expressions for the mean and variance of job inter-departure times from a workstation are obtained. These are then used as a basis for ‘linking’ workstations in a two-workstation aggregation approach. This method is compared to modelling such a system as a series of G/G/1 queues. The analysis method is easily implemented in a spreadsheet. Extensive computational experiments demonstrate the effectiveness of the overall approach.     

System integration and radiation pattern measurements of a phased array antenna employing an integrated photonic beamformer for radio astronomy applications

In this paper we describe the system integration and the experimental demonstration of a photonically beamformed four-element receiving array antenna for radio astronomy applications. To our knowledge, the work described here is the first demonstration of the squint-free, continuously tunable beamsteering capability offered by an integrated photonic beamformer based on optical ring resonator true-time-delay units, with measured radiation patterns. The integrated beamformer is realized in a low loss, complementary metal-oxide-semiconductor (CMOS) compatible optical waveguide technology. The measurements show a wideband, continuous beamsteering operation over a steering angle of 23.5 degrees and an instantaneous bandwidth of 500 MHz limited only by the measurement setup.     

The equivalence of duplicate automated serial workstations and two-workstation tandem systems and its use in serial production line analysis

In automated serial production systems it is sometimes necessary to maintain two identical workstations in series, with jobs receiving processing on only one of these two workstations. This is required because a single workstation may not have sufficient capacity to support the target throughput rate and due to cost, space, and sequencing reasons, the workstations are not arranged in parallel. We show how these duplicate automated serial workstations can be approximated by a two-workstation tandem system with zero buffer. The parameters of the tandem system are simple functions of the duplicate workstation parameters. In isolation we show that the tandem system is equivalent to the duplicate workstation system. When part of a larger serial production system, the equivalence no longer holds however, simulation testing shows that a two-workstation tandem system approximation to the duplicate workstation system is very accurate. This extends the analysis capabilities of analytical tools and simulations that are tailored for serial production systems, but do not explicitly model duplicate workstations.     

Reprogrammable optical phase array

A novel reprogrammable optical phase array (ROPA) device is presented as a reconfigurable electro-optic element. One specific application of the ROPA, a 1 x 6 electro-optic space switch, is fully described. Switching angles are within 2 degrees , and switching is achieved through a complementary metal-oxide semiconductor (CMOS) controlled, diffraction based, optical phase array in a bulk BaTiO3 crystal. The crystal is flip-chipped to the CMOS chip, creating a compact fully integrated device. The design, optical simulation, and fabrication of the device are described, and preliminary experimental results are presented.     

Magneto-optical disk drive technology using multiple fiber-coupled flying optical heads. Part I. System design and performance

A novel flying-optical-head data storage technology is described. It is based on a micro-optical recording head that contains a silicon micromachined torsional mirror for high-bandwidth track following. Multiple heads and disks are contained in a Winchester-style rotating disk drive. Single-mode optical fibers provide light delivery to and from the heads. Both polarization-maintaining and low-birefringence fiber systems have been implemented for magneto-optical (MO) recording. A fixed optics module containing a laser diode, MO detection optics, and a 1 x N fiber bundle switch has been developed as an integral part of this new recording architecture. A 5.25-in. (13.33-cm), half-height prototype drive design and its performance are presented.     

Discrete correlation processor as a building core of a digital optical computing system: architecture and optoelectronic embodiment

In this paper we present a general-purpose discrete correlation processor (DCP) expected to be the building core block of a digital optical computing system. The DCP-1 is embodied by optoelectronic devices such as a VCSEL and a complementary metal-oxide silicon photodetector. The application targets of the DCP-1 are optical interconnection and various types of digital optical computing. It is expected that digital optical computing techniques coupled with the optoelectronic technology will provide large capability and flexibility in information processing. Introduction of a processing scheme of optical array logic enlarges the applicable field of the DCP-1 as well as its processing capability. With the experimental DCP-1 a bit error rate smaller than 10(-9) was obtained for A . B? operation under a 500-kHz clock rate.     

Coarse grain parallel finite element simulations for incompressible flows

Parallel simulation of incompressible fluid flows is considered on networks of homogeneous workstations. Coarse-grain parallelization of a Taylor–Galerkin/pressure-correction finite element algorithm are discussed, taking into account network communication costs. The main issues include the parallelization of system assembly, and iterative and direct solvers, that are of common interest to finite element and general numerical computation. The parallelization strategies are implemented on a Sun workstation cluster using the Parallel Virtual Machine (PVM) message passing library. Test results are obtained with a maximum of nineteen workstations and various PVM configurations are exhibited. Parallel efficiency close to ideal has been achieved for some strategies adopted. It is suggested that load balancing may not always be beneficial on distributed platforms with broadcasting communication connection. © 1998 John Wiley & Sons, Ltd.     

一种超宽带零中频的微波光子信道化接收机

信道化接收技术是现代电子战和雷达系统的重要组成部分,是满足其高频段、大带宽、多通道同时接收等需求的核心使能技术。本文提出了一种基于微波光子的零中频接收机,可通过调整光频梳中心频率的方法使之与宽带RF信号组的中心频率相对应,从而实现3GHz的宽带射频信号的信道化接收,每个子信道带宽为600MHz且直接解调为I/Q基带信号。     

Planar-optical mesh-connected tree interconnects: a feasibility study

The mesh-connected tree is a two-dimensional interconnect topology that combines aspects of a conventional tree network and a two-dimensional nearest-neighbor mesh network. Because of its topological features, a mesh-connected tree has the potential to be implemented with planar optoelectronic interconnect concepts. We examine the feasibility of employing vertical-to-surface-transmissionelectro-photonic optical array switches together with planar micro-optical components for the future implementation of an optoelectronic mesh-connected tree interconnect.     

Review of silicon photonics: history and recent advances

Silicon photonics has attracted tremendous attention and research effort as a promising technology in optoelectronic integration for computing, communications, sensing, and solar harvesting. Mainly due to the combination of its excellent material properties and the complementary metal–oxide semiconductor (CMOS) fabrication processing technology, silicon has becoming the material choice for photonic and optoelectronic circuits with low cost, ultra-compact device footprint, and high-density integration. This review paper provides an overview on silicon photonics, by highlighting the early work from the mid-1980s on the fundamental building blocks such as silicon platforms and waveguides, and the main milestones that have been achieved so far in the field. A summary of reported work on functional elements in both passive and active devices, as well as the applications of the technology in interconnect, sensing, and solar cells, is identified.     

All-optical quaternary logic gates

Conventional binary logic based operations restrict the speed of operations as well as information handling capacity. A way to overcome these limitations is the implementation of multivalued logic operations in the optical domain. Multivalued logic operations not only enhance the data handling capacities but also increase the speed of processing. integrating enormous potential bandwidth of optical fiber as information carrying medium and faster optoelectronic/optical switches with no hardware complexity. A new method is proposed for the implementation of all-optical quaternary inversion, MAX, MIN, and equality operations using frequency-encoded data. Cross phase modulation-based frequency conversion, polarization switch (PSW) characteristics of a semiconductor optical amplifier (SOA), frequency routing by a wave division multiplexer (MUX), and a demultiplexer (DMUX) have been exploited to implement the desired quaternary logic operations. Simulation results support the feasibility of the proposed scheme.     

Workload balancing and manufacturing complexity levelling in mixed-model assembly lines

To effectively react and meet the current ever growing demand for individualised motor vehicles, built to customer specific requirements, automotive industry has accelerated its transition towards mass-customisation. As a result, the number of new model introductions has drastically increased over the past three decades. To cope with this intensified customisation, the current automotive assembly platforms are designed to assemble a wide range of relatively different models, and are turned into mixed-model assembly lines (MMALs). This implies that the set of tasks to be performed on each workstation is no longer stable but varies highly with the model-mix. As a consequence, the manufacturing complexity increases at the workstations and throughout the whole assembly system. This paper proposes a method to monitor manufacturing complexity at each workstation while the MMAL is being balanced. An entropy-based quantitative measure of complexity, which incorporates the variability of each task duration, is developed. This measure is used to monitor the manufacturing complexity level at each workstation. An integrated mixed-line balancing and complexity monitoring heuristic is proposed, to determine workload balance solutions, in which manufacturing complexity is levelled throughout the workstations composing the line. This procedure is tested on a real data-set provided by an automotive manufacturer. The results are reported and thoroughly discussed.     

Vertically oriented carbon nanofiber based nanoelectromechanical switch

We present a proof-of-principle study of a vertically aligned carbon nanofiber switch and study relevant parameters via a model for a static switch. Vertically aligned freestanding carbon nanofibers are produced by plasma-enhanced chemical vapor deposition (PECVD) and their deflection under applied voltage is measured using an optical microscope. The deflection is compared with a static force balance model, which successfully predicts the switching behavior assuming a nanofiber modulus of 40 GPa, which is consistent with independent modulus measurements made in our laboratory. The model is then extended to explore constraints for implementing a vertically aligned nanotube switch into present CMOS process flow. Carbon nanofibers of less than 40 nm in diameter, which may be grown by current PECVD technology, are shown to be acceptable for device integration for current and future CMOS scaling. To accommodate varying tube sizes and architectures, a basic scaling relationship is developed to relate CMOS via parameters and nanofiber characteristics to programming voltage.     

Split Bull's eye shaped aluminum antenna for plasmon-enhanced nanometer scale germanium photodetector

Bull's eye antennas are capable of efficiently collecting and concentrating optical signals into an ultrasmall area, offering an excellent solution to break the bottleneck between speed and photoresponse in subwavelength photodetectors. Here, we exploit the idea of split bull's eye antenna for a nanometer germanium photodetector operating at a standard communication wavelength of 1310 nm. The nontraditional plasmonic metal aluminum has been implemented in the resonant antenna structure fabricated by standard complementary metal-oxide-semiconductor (CMOS) processing. A significant enhancement in photoresponse could be achieved over the conventional bull's eye scheme due to an increased optical near-field in the active region. Moreover, with this novel antenna design the effective grating area could be significantly reduced without sacrificing device performance. This work paves the way for the future development of low-cost, high-density, and high-speed CMOS-compatible germanium-based optoelectronic devices.