Solitary wave
A soliton is a self-reinforcing "solitary wave" caused by nonlinear effects in the medium. Solitons are found in many non-linear physical phenomena, as they are found as solutions of many different non-linear differential equations. The soliton phenomenon was first described by John Scott Russell (1808-1882) who observed a solitary wave in the Union Canal, reproduced the phenomenon in a wave tank, and named it the "Wave of Translation".
Some of the equations that describe solitons are the Korteweg-de Vries equation, the non-linear Schrödinger equation and the Sine-Gordon equation.
A classic example of a soliton is the Severn bore, a wave phenomenon in the River Severn.
In 1973, Akira Hasegawa of AT&T Bell Labs was the first to suggest that solitons could exist in optical fibers. He also proposed the idea of a soliton-based transmission system to increase performance of optical telecommunications.
In 1988, Linn Mollenauer and his team transmitted soliton pulses over 4,000 kilometers using a phenomenon called the Raman effect, named for the Indian scientist Sir C. V. Raman who first described it in the 1920s, to provide optical gain in the fiber.
In 1991, a Bell Labs research team transmitted solitons error-free at 2.5 gigabits over more than 14,000 kilometers, using erbium optical fiber amplifiers (spliced-in segments of optical fiber containing the rare earth element erbium). Pump lasers, coupled to the optical amplifiers, activate the erbium, which energizes the light pulses.
In 1998, Thierry Georges and his team at France Telecom R&D Center, combining optical solitons of different wavelengths (wavelength division multiplexing), demonstrated a data transmission of 1 terabit per second (1,000,000,000,000 units of information per second).
In 2001, the practical use of solitons became a reality when Algety Telecom deployed submarine telecommunications equipment in Europe carrying real traffic using John Scott Russell's solitary wave.
See also Soliton (topological).
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