November 2000

Blazing Data

Photonics: Could a "perfect mirror" replace fiber optics?

By Erika Jonietz

Two years ago, MIT graduate student Yoel Fink built the "perfect mirror"-one that reflects light from all angles with negligible absorption. Now OmniGuide Communications, the Cambridge, Mass.-based startup Fink helped found, hopes to roll that perfection into cable that can carry light of higher intensity and a broader bandwidth, transmitting up to 1,000 times more data than fiber optics.

"Not too far in the future, we're going to bang into the limits" of conventional fiber optics, says MIT materials scientist Edwin Thomas, another OmniGuide founder. In addition to transmitting more data, the new cable could eliminate the need for signal boosters every 60 to 80 miles. And, unlike fiber optics, the cable would have no trouble transmitting light around sharp bends, allowing the cables to be miniaturized to the scale of the tiny optical switches being developed for the optical Internet ( see " The Microphotonics Revolution ," TR July/August 2000 ).

"What we are suggesting is really revolutionary, not evolutionary," says MIT physicist John Joannopoulos, the third of the company's founding trio.

The technology is essentially hollow tubing lined with the dielectric mirror first fabricated by Fink, now an assistant professor at MIT. Dielectric mirrors, widely used in photonics, are specialized mirrors with the ability to reflect specific wavelengths of light with near-perfect efficiency. Unlike the bathroom mirror, the dielectric kind is nonmetallic and not conductive, so no photons are lost by exciting electrons in the mirror. Until Fink's "perfect mirror," however, dielectric mirrors could only reflect light from a limited number of angles, allowing the rest of the light to pass through.

So far, OmniGuide has attracted $4 million in venture capital. Recently, the team went a step further creating the first dielectric coaxial cable, combining the benefits of dielectrics with the properties of the metallic coaxial cable your TV uses. For the moment, a commercial coaxial cable remains in the realm of theory, but Joannopoulos says OmniGuide may someday try to manufacture these as well.