Abstract: An optical communication system comprising a first apparatus for supplying at least three optical signals, each having a predetermined wavelength selected from a first range of wavelengths &Dgr;&lgr;; an optical transmission line, optically connected to the first apparatus, for the transmission of the at least three optical signals, the optical transmission line comprising in its turn i. at least one optical amplification system having a predetermined gain spectrum which, in the first range of wavelengths &Dgr;&lgr;, has a maximum and a minimum gain (expressed in dB), the difference between the maximum and minimum gain being &Dgr;Gtot, and ii.