Optical Interconnections for VLSI and Electronic Systems


OLIVES - 2289

Keywords optoelectronics, interconnects, VLSI


Start Date: 01-JAN-89 / Duration: 36 months

[ contact / participants ]


Objectives and Approach

The overall objective of OLIVES was to develop optical interconnections for use in advanced electronic computer and processor systems that were expected to significantly improve performance compared with the electrical alternative. The project linked four of Europe's leading optical, semiconductor and computer companies with a chemical company and five universities, and aimed towards the commercial exploitation in high-performance processors from the mid 1990s onwards.

The project focused on the development, construction and assessment of a set of demonstrators which acted as test-beds for two- and three-dimensional optical interconnections. These demonstrators covered the application of optics to both clock and data distribution at the chip, board and inter-board levels.

To provide the components required for these demonstrators a significant technological effort was made in the fields of holography, guided wave components, receiver circuitry and optical modulators. In addition, precision alignment and hybridisation techniques for both the mounting of the optoelectronic components and the registration of the boards themselves were developed.

In view of the present state of the art in the monolithic integration of active optical components and silicon circuitry, hybrid optoelectronic integration was used throughout the demonstrator construction phase. However, monolithic integration may offer great potential advantages, and in parallel with the demonstrator development a study of the growth of III-V compounds on silicon was undertaken. In addition, a study of polymeric materials for optical modulators is being included, since these may offer significant advantages over alternative techniques.

Progress and Results

During the first two years significant advances were made in the enabling technologies of holography, silica-on-silicon waveguides, precision mounting of optical elements, optical Stark modulators, detector arrays, and receiver and driver arrays in ECL and CMOS. A first prototype based on the optical mastercard was constructed. Clear applications for the GaAs-on-silicon technology in optical motherboards and optoelectronics CMOS were identified, and collaborative R&D established. The development of stable cross-linked polymers for waveguides and modulators also opened up many new possibilities.

The application assessment of the demonstrators was completed. Overall, it has become clear that the comparison of optical and electrical interconnects is very system-specific and a scheme which offers no advantages in one system may be very advantageous in another, depending on the precise system requirements. Results for the major demonstrators are as follows:

Finally, studies of the potential applications for optics to backplane busses in large departmental servers and ATM switches were initiated. For departmental servers, a first draft requirement for one of the busses in a typical 1995 system was defined: this is a 32-bit wide bus with a total capacity of 1 Gbyte/s and a maximum of 12 attached boards. This exceeds the capacity of Futurebus+ (albeit only by a relatively small margin), confirming that some other solution, for which optical is a prime candidate, is required.

All the demonstrators were achieved, and the project was completed successfully.


CONTACT POINT

Mr James Parker
BNR EUROPE LTD
London Road
UK - HARLOW CM17 9NA
tel: + 44/ 279-29531
fax: + 44/ 279-441551
telex: 81151 STL HW G

Participants

BNR EUROPE LTD - UK - C
CNM - E - P
FORTH RESEARCH CENTRE - GR - P
PLESSEY COMPANY PLC - UK - P
THOMSON-CSF - F - P
UNIVERSITY COLLEGE LONDON - UK - P
SIEMENS AG - D - P
SWISS FEDERAL INSTITUTE OF
TECHNOLOGY - CH - P
IMEC VZW - B - P
AKZO INTERNATIONAL RESEARCH BV - NL - A


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OLIVES - 2289, December 1993


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html version of synopsis by Nick Cook