Science finds way to speed telecoms

一月 5, 2001

High-speed telecommunications will become faster, more efficient and cheaper to deliver when three university-based scientific developments in Britain, Italy and Canada hit the market.

The three projects demonstrate the competitiveness among universities in developing hardware for the information market. Transmission times and the price of the nano-transporters that transport the information are all set to fall for the next generation of internet users.

Scientists at Cambridge University have come up with the technology and funding to make inexpensive microchips from plastic. This is expected to have a host of applications in semiconductor devices and is being touted as a revolution in the industry.

Most semiconductors are based on silicon which, although relatively cheap, must undergo complex production processes. The Cambridge technique is based on a family of exotic plastic materials. While scientific details remain under wraps, it is thought the semiconductors are built using techniques related to ink-jet printing, a common industrial process.

Meanwhile, Italian physicists may have taken a step towards the creation of a silicon laser. Until now, lasers and silicon were unlikely partners in opto-electronics, the marriage of electronic and light-based technology used for products such as CDs.

With silicon, the energy gets squandered. But Lorenzo Pavesi of the University of Trento and his colleagues have found that it can emit light if it is cut into very small pieces. If it is fashioned into wires, sheets or lumps measuring just a few nanometres (millionths of a millimetre) across, it begins to glow when electrically stimulated. Using this discovery, the Italians have managed to wring something close to a laser-like emission from silicon.

Colombo Bolognesi, an engineering professor at Simon Fraser University in British Columbia, Canada, agrees that silicon lasers could be a turning point. "That's the holy grail for the silicon people," he said. His team, on the other hand, has been working with compound semi-conductors, an area that is seen as the biggest competitor to silicon.

He and physicist Simon Watkins have developed a transistor that allows optical-fibre transmissions of nearly 100 billion bits a second - up to 40 times faster than high-speed telecom systems. They have created the world's fastest double heterojunction bipolar transistor, a microscopic device that controls signals transmitted on optical fibres.

Professor Bolognesi's team uses microscopic crystals with specially engineered chemical, optical and electrical properties. Watkins grows the microscopic crystals one atomic layer at a time by condensing gas mixtures.

"The crystal properties are intimately connected with the devices' performance, so a close feedback between the two groups was necessary to achieve the high (transistor) speeds," Dr Watkins said. This will help improve mobile phone circuits, reducing battery use and increasing talktime.

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