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Posted
on 26-Nov-01 05:06 AM
Prucnal making light work to accelerate the Internet
by Steven Schultz
It's been 20 years since Paul Prucnal saw the light.
It was before the Web, around the time of the first PC and when the Internet was just a specialized tool for universities and government labs. No one was downloading videos or clogging networks with e-mail, but Prucnal, a professor of electrical engineering at Princeton University, was looking for ways to make computer communications faster. And the answer, he knew, was light.
In the early 1980s, the technology of fiber optics was taking off. Researchers found that computers could transmit a lot more information by shining short pulses of light through a thin strand of glass than by sending electric current through a copper wire. Telephone companies began running fiber optic cables coast to coast.
But Prucnal, then at Columbia University, wanted to push the idea much further. The real bottlenecks, he realized, were not in the long hauls. The thin strands of glass webbing the nation were like giant water mains spilling their contents into inadequate local plumbing. The information in the light pulses had to be converted back into cumbersome electrical signals before they could be sorted and directed to their proper destinations.
Prucnal's idea was to build "all-optical networks" in which all the electronic sorting and routing equipment would be replaced by devices that deal only in light, with no conversion to electrical signals.
At the time, said Prucnal, it was a "pie-in-the-sky, crazy idea." No such device, or even the materials necessary to build it, existed. It was a little like trying to make a hand-held FM radio before the invention of the transistor.
"People didn't laugh at it," Prucnal recalled, "but they recognized that it was way in the future."
Today, Prucnal has solved several of the key problems. He invented an all-optical, microscopically small switch that is undergoing commercial development and appears to be on the verge of widespread use. With the Internet having undergone radical growth and the demand for high-speed networks soaring, his 20-year-old idea may be just in time.
For the complete story, see the Princeton Weekly Bulletin.
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