Patent ID: 7136593

Claim:
A wavelength-division multiplexed optical transmission system for transmitting an optical wavelength-division multiplexed signal using frames via an optical fiber transmitting line, comprising: a transmitter for converting an inputted electric signal into the optical wavelength-division multiplexed signal and transmitting the optical wavelength-division multiplexed signal; a receiver for receiving said transmitted optical wavelength-division multiplexed signal; a frame phase updating unit for mutually differing transmitting frame phases between at least two or more wavelength channels among a plurality of wavelength channels which are transmitted through a same optical fiber transmitting line; a frame configuration unit for configuring frames of said wavelength channels from a signal to be transmitted to said optical fiber transmitting line and selecting an output signal frame phrase itself at random; and a device for reducing mutual interference among a plurality of wavelength channel frames which are transmitted through said same optical fiber transmitting line, wherein said frame phase updating unit comprises: a phase shifter for shifting a phase by a phase delay quantity which is set on the basis of a reference frame phase that is inputted externally; and a frame phase updating circuit for setting the phase shifted by said phase shifter to an output signal frame phase itself, and wherein said phase shifter presets it to cause said phase delay quantity to mutually differ the transmitting frame phases of a wavelength channel group which is transmitted through said same optical fiber transmitting line.