Long-distance dynamic soliton transmission technology

We have developed an erbium-doped fiber amplifier (EDFA) for amplifying optical solitons and the dynamic soliton transmission method for achieving long-distance optical soliton communication. An optical soliton propagates stably over long distances without distortion by balancing the group velocity dispersion (GVD) of a fiber with its nonlinearity, known as self phase modulation (SPM). This is attractive because it makes it possible to construct a dispersion-free high-speed communication system. In the dynamic soliton transmission method, the amplitude of the soliton varies rapidly, but the soliton pulse width is kept constant after propagation by injecting a soliton into the fiber that is slightly more intense than the fundamental N = 1 soliton. The decrease in amplitude is compensated for by the EDFA. This report describes the fundamentals of dynamic soliton transmission and presents 10 Gbit/s-1200 km and 20 Gbit/s-1020 km long-distance optical soliton transmission experiments.