TRANSMISSION SYSTEM PROVIDED WITH COMPENSATION OF MUTUAL PHASE AND/OR SELF-PHASE MODULATION

摘要

PROBLEM TO BE SOLVED: To cancel the adverse influence of a mutual phase modulation and/or a self-modulation by modulating the phase of the channel of one side which is subjected to an amplitude modulation while using the signal obtained from an electric modulation used in order to modulate the channel of other side which is subjected to an amplitude modulation at a transmitter side. SOLUTION: This system has pairs of light transmitters 10 and each transmitter is modulated with the data signal of the individual channel in wavelength multiplexing channels. Individual signal outputs of the light transmitters 10 are subjected to a wavelength multiplex on an optical highway by using the multiplexer 13 just behind which a light amplifier 14a is connected at the transmitter side. Moreover, phase modulators 16 being variable delay devices exist in the system and each phase detector modulates the phase of the radiant electromagnetic wave of a related transmitter 10 with the signal obtained from the data applied to the transmitter 10 of other side. That is, each modulator modulates the phase of the channel of one side which is subjected to the amplitude modulation with the signal obtained from the electric modulation used in order to modulate the amplitude of other side which is subjected to the amplitude modulation at the transmitter side.