光电多芯片组件的自由空间光互连技术研究

自由空间光互连 (FSOI)技术使用激光在自由空间中传播 ,其表现出的特性如速度和功耗等方面较之电在连线中的传输具有的明显优点 ,从而在具有巨大发展潜力的光电多芯片组件(OE- MCM)中得到了广泛的重视。本文在建立了 OE- MCM的物理模型、逻辑模型及开销模型的基础上 ,着重对 OE- MCM中的互连分割、互连距离 (MID)最小化和 FSOI互连设计几个方面进行了研究。     

Physical models and algorithms for optoelectronic MCM layout

Future computers will need to incorporate the parallelism of optical interconnections in order to achieve projected performance within reasonable size, power and speed constraints. This is necessary since optical interconnections have advantages in size, power, and speed over “long” distance communication. These features make optical interconnects ideal for inter-module connections in multichip module systems. Free-space optical interconnection can be one form of optical interconnections. Computer generated holograms (CGHs) are extremely attractive optical components for use in free space optical interconnections due to their ability to be computer designed. We will show that the fabrication limitations of CGHs for general interconnection networks require the need for placement algorithms for large processing element (PEs) arrays. In this paper, we will demonstrate that these fundamental CGH fabrication limitations greatly influence the computer aided design of optoelectronic interconnect networks that utilize CGHs for optical interconnections. Specifically, we show that the minimum feature size directly affects the logical placement of processing elements. Various physical models for free-space optical interconnects in parallel optoelectronic MCM systems are then identified from which we derive several logical models for analysis. We then analyze these cases and present algorithms to solve the associated layout problems. Design examples are given to illustrate the benefits of utilizing these placement algorithms in real optoelectronic interconnection networks     

有机聚合物光波导制作工艺综述

有机聚合物光波导光互连已成为实现短距离计算通信设计目标的最佳解决方法。短距离光互连是未来互连方向,综合性能优良的聚合物多模光波导是光互连中的重要组成部分。有机聚合物光波导的制作工艺对光波导的性能具有重要影响,故此对有机聚合物光波导的制作工艺进行了综述,并提出了一些未来的研发方向。     

光互连研究进展

光互连在高度并行、高速、大容量的数字系统和智能计算等领域显示了卓越的潜能。文章首先比较了在超大规模集成系统（ＶＬＳＩ）中光互连和电互连的优劣,总结了各种类的光互连及近年取得的新进展,并分析了光互连遇到的困难和未来前景。     

Fully embedded board-level guided-wave optoelectronic interconnects

A fully embedded board-level guided-wave optical interconnection is presented to solve the packaging compatibility problem. All elements involved in providing high-speed optical communications within one board are demonstrated. Experimental results on a 12-channel linear array of thin-film polyimide waveguides, vertical-cavity surface-emitting lasers (VCSELs) (42 μm), and silicon MSM photodetectors (10 μm) suitable for a fully embedded implementation are provided. Two types of waveguide couplers, titled gratings and 45° total internal reflection mirrors, are fabricated within the polyimide waveguides. Thirty-five to near 100% coupling efficiencies are experimentally confirmed. By doing so, all the real estate of the PC board surface are occupied by electronics, and therefore one only observes the performance enhancement due to the employment of optical interconnection but does not worry about the interface problem between electronic and optoelectronic components unlike conventional approaches. A high speed 1-48 optical clock signal distribution network for Cray T-90 super computer is demonstrated. A waveguide propagation loss of 0.21 dB/cm at 850 nm was experimentally confirmed for the 1-48 clock signal distribution and for point-to-point interconnects. The feasibility of using polyimide as the interlayer dielectric material to form hybrid three-dimensional interconnects is also demonstrated. Finally, a waveguide bus architecture is presented, which provides a realistic bidirectional broadcasting transmission of optical signals. Such a structure is equivalent to such IEEE standard bus protocols as VME bus and FutureBus     

Modellierungs- und Simulationsverfahren für die optische Verbindungstechnik auf elektrischen Leiterplatten

Optical interconnection technology on the printed circuit board level is a key technology for future microelectronic equipment. The consideration of functional, technological, and economical requirements results in a hybrid solution, where electrical and optical interconnects are integrated into one substrate called electrical optical printed circuit board. The significant part of the entire design process for electrical optical printed circuit boards is marked by the design supporting modelling and simulation of optical interconnects. Based on an abstract model for an entire optical interconnect a simulation model for optical multimode-waveguides is presented, taking into account all significant waveguide properties. Apart from that, the modeling of active components (laser- and photo-diodes) is addressed.     

一种宽带光总线互连网络机群系统设计

介绍了一种宽带光总线互连网络机群系统。该系统利用宽带多层自由空间光学数据总线和VCSEL/MSMCMOS光电子集成器件实现4台计算机之间互连。专用通讯适配器实现高性能并行接口(high performance parallel interface,HIPPI)到外设部件互连(peripheral component interconnection,PCI)协议转换。该系统光互连网络传输容量可达60Gbit/s,可用于计算机之间的高速通讯。     

光互连与面发射激光二极管

为克服光通信、电子计算技术等的速度限制,采用光互连是一种有效途径。光互连也是光计算机的基本技术。文中对光互连技术进行了分析,并介绍了一种有利于光互连的最理想光源——面发射激光二极管。     

超高速光互连系统级封装技术前沿研究

光互连系统级封装技术是用光互连在封装尺度上代替铜互连,以突破目前芯片间通信低速度瓶颈。超高速光互连系统级封装的目标是开发出可集成光子收发器,并嵌入到现代尖端的系统级封装中(SiP)中,以提高并行计算系统的数据传输效率或速度。文章介绍了超高速光互连系统级封装关键技术及前沿研究情况,通过分析IMEC、Intel、BAE系统公司等研究机构的开发现状和技术发展路线,论述了光互连SiP关键技术的发展趋势。     

Optical computing and interconnects

This paper discusses the present status of optical computing and interconnects, including device technology, and recent progress in three types of optical computing-analog, digital, and neural-is introduced. Examples of technologies used in an analog computing system, a technique for the optimal design of coherent phase-only spatial filters, and a new version of incoherent filtering are presented. The use of the modified sign digit number representation and its applications to digital optical computing are also described. Some architectures for optical neural computing are introduced, and the importance of optical interconnect technology in parallel computing is stressed. Permutation techniques, the board-to-board level interconnection techniques, and switching techniques are reviewed. Recent developments in optoelectronic devices and passive optical elements are outlined and finally some technological issues in optical computing and interconnects for practical use are discussed     

Optical interconnections within modern high-performance computingsystems

Optical technologies are ubiquitous in telecommunications networks and systems, providing multiple wavelength channels of transport at 2.5-10 Gbps data rates over single fiber-optic cables. Market pressures continue to drive the number of wavelength channels per fiber and the data rate per channel. This trend will continue for many years to come as e-commerce grows and enterprises demand higher and reliable bandwidth over long distances. E-commerce, in turn, is driving the growth curves for single-processor and multiprocessor performance in data-base transaction and Web-based servers. Ironically, the insatiable taste for enterprise network bandwidth, which has driven up the volume and pushed down the price of optical components for telecommunications, is simultaneously stressing computer system bandwith-increasing the need for new interconnection schemes-and providing for the first time commercial opportunities for optical components in computer systems. This paper will center primarily on the use of optical interconnects within commercial digital computing systems, particularly workstations and servers, and will address mainly board-board interconnects within a single cabinet or box. We feel this is the most likely utilization of optics in commercial computer systems for the next decade. We will also provide a practical analysis of inter-and intrachip optical interconnects and the difficulties they face in real systems     

Progress in complementary metal-oxide-semiconductor silicon photonics and optoelectronic integrated circuits

Silicon photonics is an emerging competitive solution for next-generation scalable data communications in different application areas as high-speed data communication is constrained by electrical interconnects. Optical interconnects based on silicon photonics can be used in intra/inter-chip interconnects, board-to-board interconnects, short-reach communications in datacenters, supercomputers and long-haul optical transmissions. In this paper, we present an overview of recent progress in silicon optoelectronic devices and optoelectronic integrated circuits(OEICs) based on a complementary metal-oxide-semiconductor-compatible process, and focus on our research contributions. The silicon optoelectronic devices and OEICs show good characteristics, which are expected to benefit several application domains, including communication, sensing, computing and nonlinear systems.     

平行光纤互联技术：高性能和低能耗的结合

This paper analyzes the physical potential,computing performance benefit and power consumption of optical interconnects. Compared with electrical interconnections, optical ones show undoubted advantages based on physical factor analysis. At the same time, since the recent developments drive us to think about whether these optical interconnect technologies with higher bandwidth but higher cost are worthy to be deployed, the computing performance comparison is performed. To meet the increasing demand of large-scale parallel or multi-processor computing tasks, an analytic method to evaluate parallel computing performance of interconnect systems is proposed in this paper. Both bandwidth-limit model and full-bandwidth model are under our investigation. Speedup and efficiency are selected to represent the parallel performance of an interconnect system. Deploying the proposed models, we depict the performance gap between the optical and electrically interconnected systems. Another investigation on power consumption of commercial products showed that if the parallel interconnections are deployed, the unit power consumption will be reduced. Therefore, from the analysis of computing influence and power dissipation, we found that parallel optical interconnect is valuable combination of high performance and low energy consumption. Considering the possible data center under construction, huge power could be saved if parallel optical interconnects technologies are used.     

Optics and supercomputing

Storage, interconnection, and processing are discussed. Various types of optical disks and page-oriented holographic memories are considered. It is shown that optical storage is advancing rapidly and holds the potential of hundreds of megabytes per second data rates from a single storage unit, which can provide many new opportunities for supercomputing. Module-to-module, board-to-board, and chip-to-chip interconnection and gate-to-gate communication are discussed. It is concluded that optical interconnection is, in many cases, superior to electronic interconnection and holds the key to the development of future electrooptic systems. Optical computing devices are discussed and various application areas where optical processing as well as storage and interconnection are expected to play a role in the future are considered. The authors believe that optical processing, while holding considerable promise, lags behind its electronic counterpart primarily due to the fact that digital optical device development is in its infancy. They predict near-term systems will be electrooptic, with each technology providing its strength to the problem at hand     

Precision Molding of Polymeric Multi‐Channel Optical Interconnection Devices Considering the Coefficient of Thermal Expansion of the Materials

Polymeric multi‐channel optical interconnection devices that are usually fabricated by transfer molding are indispensable for parallel interconnection in high speed, high capacity optical communication systems. This paper proposes a design technique considering the thermal behavior of materials, such as shrinkage and expansion during the molding process, to satisfy geometrical requirements that have less than 1 μm tolerance. We also designed molds considering the thermal effects of the materials and fabricated multichannel optical fiber connectors that have less than 1 μm tolerance.     

光互联背板研究现状

随着高性能计算和高速通信等技术的飞速发展,信息量呈指数暴增,对高速背板带宽、速率、互联密度及制造工艺等要求越来越高。光互联背板具有高速率、高带宽、低功耗、低损耗和抗电磁干扰等优势,可有效解决电互联高速背板的技术瓶颈。本文对光互联背板制造技术的研究现状进行了阐述与分析,探讨了光互联背板的关键技术及未来发展方向。     

Wavelength assignment for locally twisted cube communication pattern on optical bus network-on-chip

Optical network-on-chip (NoC) is a new designing of Multi-Processor System-on-Chip (MPSoC). Global bus is the simplest logical topology of optical NoC. Static routing and wavelength assignment is one important communication mechanism of optical NoC. This paper addresses the routing and wavelength assignment (RWA) problem for locally twisted cube communication pattern on global bus optical NoC. For that purpose, a routing scheme, that is an embedding scheme, is proposed, and a wavelength assignment scheme under the embedding scheme is designed. The number of required wavelengths is shown to attain the minimum, guaranteeing the optimality of the proposed scheme.     

自由空间光互连系统的结构和设计分析

光互连技术是光通信网络的基础。文章结合现代微电子系统中所采用的自由空间光互连技术,进行较全面的光互连结构和设计分析     

Optical fiber interconnection for the scalable parallel computingsystem

In this paper, we discuss the optical fiber interconnection technologies applied in the two types of parallel processing systems: 1) a backplane interconnection in a parallel processor array system and 2) a computing cluster network. We have set up a parallel processor array system using optical fiber to make point-to-point interconnection between processor elements and are developing a low-cost virtual parallel optical fiber interconnection link (VPOFLink) complying with peripheral component interconnect (PCI) local bus specifications for the computing cluster. VPOFLink is integrated with the popular PCI bus interface in order to make the link hold the same bandwidth as that of the PCI bus. It was fabricated as an available peripheral device that can been inserted into the bus slots of commercial computers directly and can operate under the control of PCI bus. Also in this paper, we demonstrate the optical fiber link for a ring network and the architecture of the ring network     

A prototype 3D optically interconnected neural network

We report the implementation of a prototype three-dimensional (3D) optoelectronic neural network that combines free-space optical interconnects with silicon-VLSI-based optoelectronic circuits. The prototype system consists of a 16-node input, 4-neuron hidden, and a single-neuron output layer, where the denser input-to-hidden-layer connections are optical. The input layer uses PLZT light modulators to generate optical outputs which are distributed over an optoelectronic neural network chip through space-invariant holographic optical interconnects. Optical interconnections provide negligible fan-out delay and allow compact, purely on-chip electronic H-tree type fan-in structure. The small prototype system achieves a measured 8-bit electronic fan-in precision and a calculated maximum speed of 640 million interconnections per second. The system was tested using synaptic weights learned off system and was shown to distinguish any vertical line from any horizontal one in an image of 4×4 pixels. New, more efficient light detector and small-area analog synapse circuits and denser optoelectronic neuron layouts are proposed to scale up the system. A high-speed, feed-forward optoelectronic synapse implementation density of up to 10⁴/cm² seems feasible using new synapse design. A scaling analysis of the system shows that the optically interconnected neural network implementation can provide higher fan-in speed and lower power consumption characteristics than a purely electronic, crossbar-based neural network implementation