Light that acts like `natural bits' [solitons]

Solitons, ultrastable light pulses that could revolutionize long-haul, fiber-optic communications and perhaps even optical switching, are discussed. Two classes of solitons are described. Temporal solitons, pulses of light that resist a medium's chromatic dispersion, or tendency to broaden them in time, have been known for a while. They offer the possibility of all-optical communication systems transmitting signals thousands of kilometers. Erbium-doped fiber amplifiers provide an all-optical form of soliton amplification that brings such lightwave systems closer to reality. Spatial solitons, which are actually light beams that travel through a planar waveguide without self-focusing or spreading, were observed for the first time last year and might eventually prove useful for optical switching