Miscellaneous

Contents

This page contains documents and projects cannot be filed just under one specific research category.

Interconnects

Abstract: This literature survey will give an overview of electronic interconnect patterns, polymer waveguides and FPGA’s.

C. J. Moir, Interconnects, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, UK, March 2003.

Download the literature search in PDF format (1.1MB).

Optically Interconnected Computing Systems

Abstract: Future computing systems will offer greater processor performance using either conventional or emergent technologies. However, few of these systems address data locality issues such as moving information from processor to memory, storage or another processor. Electrical interconnection even across a large substrate is becoming prohibitive due to intrinsic bandwidth limitations. Optoelectronics is presently the only viable solution to alleviate this problem and has already superseded electronics for longhaul transmission. This thesis examines the benefits of optical interconnection at a short range chip-to-chip level, both in free space and in a waveguide. It shows that optoelectronics enables a connectionist approach to computing allowing the construction of architectures such as a neural network. Simulation maps the assignment problem to this type of architecture and underlines both its performance and startling scalability. The algorithm is then implemented, resulting in the construction of two optoelectronic neural network demonstrators, both of which use high density free-space optical interconnection. The respective performance of these demonstrators is then examined. Finally, the mutual benefits of integrating an optical interface to dynamically reconfigurable field programmable gate arrays (FPGAs) are considered.

K. J. Symington, Optically Interconnected Computing Systems, Ph.D. Thesis, Department of Physics, Heriot-Watt University, Edinburgh, UK, November 2001.

Download the thesis in PDF format (7.2MB).

Electronic Design Issues in High-Bandwidth Parallel Optical Interfaces to VLSI Circuits

Abstract: This thesis investigates electronic design issues in systems using parallel optical interconnections to provide terabit/s scale I/O to VLSI circuits. It focuses on the design of arrays of transimpedance photoreceiver circuits in the context of optically interconnected digital switching systems. The trade-offs in photoreceiver design are discussed. Transistor mismatch is shown to limit receiver sensitivity. Trends in performance in future CMOS technology are projected. By the 0.1 µm generation, the analysis forecasts a major improvement in electrical power consumption but, due to transistor mismatch, only a limited improvement in optical switching energy. The design of the receiver subsystem for a prototype optoelectronic-VLSI switching system, implemented in a hybrid 0.6 µm CMOS-InGaAs MQW modulator technology, is used to provide several case studies. The system is designed to implement a 1 Tbit/s optical interface using 4096 optical channels operating at 250 Mbit/s. Two receivers for this system are described. Experimental results from prototypes tested with electrical inputs verify that the designs meet the DC sensitivity requirements of the system. One of the designs applies the transconductance-transimpedance circuit technique to this application area for the first time. A detailed study of the merits of this approach in high bit-rate post-amplifiers shows that its high gain-bandwidth product can improve sensitivity at some cost in power consumption and layout area. A method for analysing electrical crosstalk through the power supply network in twodimensional receiver arrays is presented. A case study shows that crosstalk has a major impact on the performance of single-ended receivers suggesting that electrically differential designs may be advantageous. The work concludes that, although certain challenges remain, electronic design issues are unlikely to prevent parallel optical interconnects from meeting the I/O requirements of future VLSI circuits.

M. G. Forbes, Electronic Design Issues in High-Bandwidth Parallel Optical Interfaces to VLSI Circuits, Ph.D. Thesis, Department of Physics, Heriot-Watt University, Edinburgh, UK, March 1999.

Download the thesis in PDF format (4.1MB).

Quantum Computing

Abstract: A computer with memory that is exponentially larger than its size may sound ridiculous but it is in fact almost a reality. This report introduces the reader to the theory of quantum computing and proceeds to outline four implementation theories: quantum dots, ion traps, quantum optical and nuclear magnetic resonance (NMR). But which quantum technology is the most promising for the future?

K. J. Symington, Quantum Computing, Department of Physics, Heriot-Watt University, Edinburgh, UK, November 1997.

Download the literature search in PDF format (1.7MB).

Last Modified 22/04/03 09:32:28.