Considerations on high speed transmission

Speed limitations of conventional transmission and future research directions are discussed. There has been steady progress for both optical devices and transmission techniques toward transmission above 2.5 Gb/s. Erbium fiber amplifiers, with their extremely wide bandwidth, have provided increased performance for both optical transmitters and receivers as well as offering efficient line amplifiers. Such devices and techniques now make it possible to demonstrate the feasibility of practical systems up to 10 Gb/s, and there are interesting possibilities for doubling and even tripling this rate. At such rates, proper consideration must be given to source spectral characteristics, even for short systems. On very long repeatered systems, such as submarine cables, nonlinear effects also become significant and could severely limit performance. However, by careful design these can be made to counter chromatic dispersion to provide a soliton system