FIELD: optical communication. SUBSTANCE: optical communication system incorporates aid designed to generate optical signals of various lengths of waves, fibre-optical line with amplifier, preamplifier and receiving aid which preamplifier has optical waveguide doped with rare-earth metal, aid for differentiated attenuation located in first position along doped fiber that provides for attenuation of signal band exceeding attenuation on length of pumping wave and filtering aid located in second position and meant to attenuate spontaneous radiation in band of wave lengths adjacent to signal band by value exceeding preset minimum. EFFECT: formation of transmission line with wide working band at levels of spontaneous radiation comparable with level of signal. 63 cl, 16 dwg
