Photonics, a field whose promoters say could someday rival or even supersede electronics, took an important step forward when engineers at AT&T Bell Laboratories demonstrated a new kind of optical amplifier.

The wonders of electronics result from manipulations of electrons, which are charged subatomic particles. Photonics, which uses the particles of light called photons, could in principle do everything electronics can do, but better. Photonic devices, using glass fibers for wires, should be able to handle more information faster than comparable electronic devices. They would also be immune to disturbance from electrical fields, such as those generated by lightning and atomic bomb explosions.

The Bell Labs researchers have demonstrated an optical amplifier that is so effective it allows the span between repeaters, which boost a dimming signal in a fiber optic cable, to be increased to a record-breaking 230 miles. The amplifiers are also the first that work without having to convert the optical signal into electronic form and back into photonic.

"This experiment shows that optical amplifiers may be practical in the future," said David Lang, director of the Bell Labs research facility.

Engineers describe the amplifier as a "converted laser" that, when stimulated by an incoming light signal, emits its own light a thousand times brighter. The achievement will be reported next month at the international Conference on Optical Fiber Communication and Optical Fiber Sensors in New Orleans.