The transmission system is suitable for amplitude modulated controlled phase optical signals (S) having an optical phase in each low level pulse that precedes or follows a high level pulse. The system includes an optical link (L) and, to allow a high transmitting power, optical corrector means (FG) are provided for applying optical filtering to the signal R at the exit (B) of the link and/or at one point or a plurality of points of the link (L), to compensate widening of its spectrum that the controlled phase signal (S) may suffer because of phase self-modulation during its transmission. Application to long-haul optical transmission.