Text: Success Reported In Revolutionary Photon Chip Tests 17 Dec 1998, 3:07 AM CST By Craig Menefee, Newsbytes. CHICAGO, ILLINOIS, U.S.A., Florida-based high tech start-up Nanovation Technologies, Inc. says its lab at Northwestern University has made a working, fully integrated optical circuit that could have revolutionary effects on computing. The circuit works with photons instead of electrons. According to the firm, a light-operated or photonic chip would be up to 1,000 times smaller than electron-based semiconductor circuits and could boost chip speed and data capacity by a factor of 100 to 1,000. Unlike conventional electron-based switched, a photonic switch uses no bias voltages or currents. Instead, it controls a light-borne signal using frequency harmonics, photon tunneling, microcavity lasers and atomically smooth optical wave guides called "photonic wires." Such terms may sound like the technical baffle-gab of a Star Trek script but the results are real enough. The university has even taken an equity position in the patented technology -- the first time it has not just settled for royalties on inventions made in its facilities. Inventions this far out on the bleeding edge of technology can take 10 years to appear in high-end commercial applications. It can be 15 years before they appear in homes or in gadgets like cellular flip-phones. But Bob Tatum, Nanovation's chief executive officer (CEO), says photonic switching -- he does not use the term "light switches" -- will be widely used much faster than that. In fact, he told Newsbytes, Nanovation is already having proof-of-concept sessions with major technology companies. Tatum says devices using optical logic chips, based on the switch circuit announced this week, could start to appear as early as the year 2,000. Tatum has some good credentials. He is a former senior vice president of technology at General Electric's information services division and others in the industry take him seriously. Still, it will take more than pure speed and capacity to drive such fast adoption, even though performance at 100 times or more the speed of electronic circuits hardly hurts. Just as importantly, Tatum says, the process for making photonic circuits is "consistent with current semiconductor fabrications ­ it is silicon based, using materials like gallium arsenide that are not terribly exotic." Creating the wave guides requires methods that are well understood by the semiconductor industry. The processes have formidable names like reactive ion beam etching and inductively coupled plasma processing. Northwestern University's prototype production line was designed virtually from scratch by the UK's Oxford Instruments, which Tatum says has called Northwestern's etching line the most advanced in North America for sub-micron lines. The term "advanced" understates what Oxford Instruments achieved. Tatum says the connections or "wires" between features in a photonic circuit are as small as 0.02 microns -- not 0.20 microns, like some fairly advanced electronic circuits, but ten times finer. Such etching takes precision right down to the atomic level, says Tatum, but wires that tiny are needed because photons travel best in much more confined spaces than electrons. "Our patents all refer to strongly confined space, meaning the light travels in very narrow, very confined space with very little leakage or loss," Tatum explained. "As a result, we can bend the light in a quarter-micron radius, which is necessary in a dense integrated circuit -- or in our case, integrated optics." Tatum says the actual processes used by the working circuit are proprietary but in layman's terms, they resemble the resonance that causes a tuning fork, when brought near a second, vibrating tuning fork, to start to vibrate in sympathy. "Instead of a tuning fork, we use a photon resonator cavity, called a quantum well, that resonates at a particular frequency," he told Newsbytes. "When you pass a wire close to the well and a photon is in the wire at the same precise frequency as the well, the two will couple. It's called tunneling -- the photon will disappear from the photonic wire and tunnel into the resonator well." He continued, "Now, if there is a second photonic wire on the other side of the well, another photon at the same frequency will tunnel from the quantum well into the second wire." In effect, the resonating well frequency determines whether a photon tunnels into the well or continues on its merry way. And that becomes the basis of logic devices that use light instead of electrons. Tatum added, "Now here's where it gets beautiful. Take 32 channels, like in wave division multiplexing, and run it down that first wave guide. The light in one of those multiplexed channels is at the resonant frequency of the quantum well. It will be picked off that stream and coupled into the other wave guide while the rest of the light continues on its way. In electronics terms, they call that de-multiplexing. " He paused. "It is a huge breakthrough. Huge. We have here, in a single, passive device, a working de-multiplexer. With 32 different frequencies you could de-multiplex 32 frequencies from a single wave guide. Without any electronics." A scramble has begun among corporations and universities to research the use of photonic technology, largely because of its speed and information-carrying capacity. Tatum says one obvious use is to replace computer processors. "Because photonic circuits are smaller and more efficient, they don't use as much power," Tatum said. "A laptop could run for three weeks on the same battery. And you know what? You don't have to put a fan on top of our circuits like you do on an IC (integrated circuit) because they don't heat up." Nanovation holds patent rights on the photonic technology, which was developed initially at Cornell University and later refined at Northwestern by a team led by Dr. Seng Tiong Ho. Ho is a professor in the Electrical Engineering and Computer Sciences Department at Northwestern but came there from the advanced quantum physics laboratory at Bell Labs, the home of the original transistor. Tatum says the earliest uses for light-operated logic will most likely be found in industries that need ever greater bandwidth, such as telecommunications, large networks and data storage. Nanovation is on the World Wide Web at http://www.nanovation.com . Reported by Newsbytes News Network, http://www.newsbytes.com . 03:07 CST (19981217/WIRES PC/CHIPTECH/PHOTO) Copyright (c) Post-Newsweek Business Information, Inc. All rights reserved

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