UCL Discovery

Abstract

Digital information, encoded onto light signals, is regularly sent along optical fibres over distances varying from a few metres to thousands of kilometres. Fibres have largely replaced traditional copper cables for high performance broadband communication over distances exceeding a metre, as they offer advantages such as lower cost, immunity to electrical interference and weight savings. Printed circuit board (PCB) backplanes are widely used in the electronic cabinets, or racks, that form the heart of a variety of IT systems and incorporate connectors to allow other PCBs to be attached and detached at right angles (Figure 1). In the highest speed computers, for communication between the central processor arrays, hard disc storage arrays, and through data routing switches, there is now considerable interest in incorporating high speed "optical wiring," by means of plastic light-guides, within large, metre-scale, electrical PCBs combining optical and electrical interconnections (OPCBs).