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Bringing The Speed Of Light To Computer Chips


Developments to Watch

Bringing the Speed of Light to Computer Chips

COMPUTING WITH LIGHT--using photons instead of electrons to transmit signals--is a technology that has long been just around the corner. Now, that corner has been turned, literally.

Photonic chips promise big increases in speed because they can pump data 100 to 1,000 times faster than silicon circuits. But there's a hitch: Photons normally won't zip around corners the way electrons do. Without that, photonic chips would be forever huge and expensive, because every "corner" would have to be a curve--a section cut from a circle with a radius of a few millimeters, or upwards of 0.1 inch.

That changed last month. Researchers at the Nano-Photonics Laboratory on Northwestern University's Evanston (Ill.) campus sculpted photonic corners with arcs as tight as 0.25 microns, or 0.00001inches. How? By digging deep trenches on both sides of optical waveguides, or "wires." The air in the trenches insulates the waveguides and keeps the photons inside. The waveguides connect to an optical-switch "transistor," producing what lab director Mee-Koy Chin says is the first all-photonics computer chip--ideal for the computerized switches in today's fiber-optic telecom networks and, in the future, perhaps even optical computers.

To speed the technology to market, G. Robert Tatum renamed the company that funded the $5.2 million lab. Tatum used to be president of Miami-based U.S. Integrated Optics Inc. But he couldn't get a trademark on that name for a planned stock offering. So USIO is now Nanovation Technologies Inc.EDITED BY OTIS PORTReturn to top

How Ultrasound Scopes Out the Material World

SINCE IBM SCIENTISTS INVENTED THE SCANNING TUNNELING MICROSCOPE (STM) in 1981, the concept has spawned an ever larger family of instruments that can create images of the atomic structures of materials. Coming next: the ultrasonic force microscope, or UFM.

The STM and its descendants work like supersharp phonographic needles--they trace the contours of individual atoms on a material's surface. But what has eluded scientists are images of the subsurface interfaces between two different materials. How their atomic lattices match up is crucial to the performance of semiconductors, ceramics, and polymer alloys.

Enter UFM. Using its pointy tip to transmit ultrasonic waves, the device works as a sort of metal detector to probe materials. In the December issue of Materials World, published by the Institute of Materials in London, Oleg V. Kolosov reports that a UFM has mapped the germanium atoms in silicon-germanium semiconductors and spotted defects in ceramic compounds--with resolutions down to 4 nanometers (a human hair is 20,000 times thicker). Kolosov helped invent UFM technology while in Japan in 1993 and 1994. Now at England's Oxford University, he still collaborates with Japanese scientists and leads a local team that's uncovering new uses for UFM.EDITED BY OTIS PORTReturn to top

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Speakers That Won't Take over Your Living Room

BIG COMPUTER MONITORS ARE GETTING SHOVED ASIDE BY FLAT-PANEL REPLACEMENTS--and bulky speakers could be next. Kwong Quest LLC of Taiwan last November unveiled its Benwin-brand speakers. Just a quarter of an inch thick, they're based on flat-panel technology from NXT PLC in Huntingdon, England. Japan's NEC Corp. has launched its own version using the same technology. All told, 76 manufacturers have licensed NXT technology. At least a dozen plan to introduce products this year, says Robert Young, a consulting engineer in San Diego.

Unlike normal speakers, which use pulsating cones to move air and generate sound, the flat speakers rely on simple panels of lightweight, rigid material. Excited by a 1-inch-thick magnetic motor, the panels vibrate minutely. But they pack a big wallop in the 60-hz to 18-khz range--much like the sounding board of a violin. For deep bass, Kwong Quest bundles a subwoofer with a set of 5-by-7-inch speakers for $129. Companies may also throw in frames and stands so the speakers can hide behind photos.EDITED BY OTIS PORTReturn to top


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