Fiber handles powerful pulses

Researchers from Cornell University and Corning, Inc. have shown that it's possible to preserve the shape, intensity and color of a very high-power light pulse as it travels through 200 meters of a fiber-optic cable.

The method could be used to deliver very high-power pulses to very precise locations for industrial and medical applications, and to make high-power lasers and amplifiers.

Light contains different wavelengths, or colors. As a light pulse travels, its wavelengths can shift to a slightly different size, wavelengths can be diverted to weaken the pulse, and its overall shape can change.

To get around these problems, the researchers used solitons, or light pulses whose shapes are resistant to change, and sent them through a hollow optical fiber made from a photonic crystal and filled with xenon gas rather than air or a vacuum.

The xenon prevented the solitons from shifting toward longer wavelengths. Making the fiber from photonic crystal enabled the researchers to transmit pulses stronger than 5 million watts without the pulse losing power or intensity. Photonic crystals are tiny structures made from rods or perforated solids that allow certain wavelengths through and block others.

High-power solitons could be used in practical applications within two years, according to the researchers. The work appeared in the September 19, 2003 issue of Science.