Patent ID: 7519296

Claim:
An optical transmission apparatus transmitting a wavelength division multiplexed light containing a plurality of signal lights having different modulating rates which are arranged on wavelength grids at predetermined intervals, comprising: a demultiplexing section comprising: an optical coupler branching said wavelength division multiplexed light to send the branched lights to a plurality of routes respectively corresponding to said different modulating rates; a plurality of demultiplexers respectively demultiplexing the lights sent to the plurality of routes by said optical coupler in accordance with transmission bands whose center wavelengths are set on said wavelength grids while maintaining intervals corresponding to modulating rates of said routes; a plurality of optical switches connected to respective output ports of said demultiplexers; and a control section that changes over optical paths on said plurality of optical switches according to the setting of wavelengths and modulating rates of the respective signal lights contained in said wavelength division multiplexed light, to transmit the signal lights having the modulating rates corresponding to said demultiplexers but to block the signal lights having other modulating rates, among the signal lights output from the respective output ports of said plurality of demultiplexers; and a multiplexing section comprising: a plurality of multiplexers respectively multiplexing said plurality of signal lights sent to a plurality of routes respectively corresponding to said different modulating rates in accordance with transmission bands whose center wavelengths are set on said wavelength grids while maintaining intervals corresponding to modulating rates of said routes; an input control section that gives only the signal lights having the modulating rates corresponding to said multiplexers to respective input ports of said multiplexers; and an optical coupler further multiplexing the lights respectively multiplexed by said plurality of multiplexers.