Abstract
Current progress on long-distance soliton transmission technologies is summarized, in which the use of erbium-doped fiber amplifiers has been a major breakthrough for the soliton communication. Techniques which can send solitons over unlimited distance are described, in which soliton control in time and frequency domains plays an important role as an optical 3R repeater. Finally, a new soliton transmission technique which employs dispersion allocation is described, which enables us to bring the soliton transmission into a developmental stage.
