The Hindu : Is this silicon's new `optical age'?

Online edition of India's National Newspaper
Wednesday, Feb 18, 2004

Business

Business

Is this silicon's new `optical age'?

By Anand Parthasarathy

SAN FRANCISCO, FEB. 17. Scientists at chip making leader Intel have created silicon devices that behave like fibre optics — turning electrical ones and zeroes into optical pulses and back again at very high speeds — in effect removing the old distinction between the separate worlds of electronic and optical ways of handling digital data.

In the first-ever public demonstration of a silicon-based optical modulator, on the eve of the Intel Developer Forum here, global media representatives saw engineers split a beam of light into two separate beams as it passed through a tiny finger-nail-sized slab of silicon, then use a transistor-like device to hit one beam with an electric charge, inducing what is known as a phase shift. When the two beams of light are re-combined the light exiting the chip went on and off at over one gigahertz (one billion bits of data per second), 50 times faster than previously produced on silicon.

Mario Paniccia, Director of Intel's Photonics Technology Lab and leader of the team which developed the silicon light encoder, explained that other building blocks of an all-optical way of processing data and sending it at high speed, over long distances, remained to be realised in silicon — and a practical commercial system may not be available till the end of the decade. However, the breakthrough is nevertheless considered significant because it cannily builds on the semiconductor industry's four-decade experience in putting millions of transistors on silicon — and then harnesses it for a future era of optical processors.

The technology implication has been briefly described in the current (February 12) issue of the British journal Nature in a note entitled `The Optical Age of Silicon'' by Graham T. Reed. The detailed technical paper by the Intel team will appear in the February 22 issue of the same journal.

Today's demonstration also gives the answer to the question that has been worrying semiconductor physicists for some time now: How many transistors can one squeeze on to a stamp-sized slab of silicon — current computer chips, typically accommodate between 50 and 80 million — before they hit a physical limit? Intel would like to think that if current chip technology finally hits a wall, they would neatly convert the electronic data into photonic ones and zeroes — but still use silicon as the base material.

This is of course convenient for chip makers such as Intel who have invested heavily in silicon fabrication plants or `fabs' around the world. But Kevin Kahn, Senior Fellow at Intel's Communications Technology Lab, told The Hindu that this was not a case of " You have a hammer - so you think the world is a nail". Using silicon to handle optical data made sound commercial sense because it was a cheaper alternative to fibre optical materials which have hitherto made an all optical processor costly and unviable, he added.

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