Patent ID: 8374504

Claim:
An optical communication system comprising an optical line terminal (OLT) connected to a trunk optical fiber, and a plurality of optical network terminals (ONTs) connected to branched optical fibers diverged from said trunk optical fiber, wherein each of said ONTs comprises: a plurality of code-division spreaders, each having a different spreading code as allocated by the OLT; a reception processing unit that selectively distributes transmission data to the plurality of code-division spreaders; at least one optical transmitter that transmits a signal spread with a code to said branched optical fiber as an optical signal of a carrier wavelength different from that of the other optical transmitters; and a signal multiplexing unit that selectively supplies output of the plurality of code-division spreaders to the optical transmitter, wherein each ONT converts the transmission data into a CDMA signal by the plurality of code-division spreaders having different spreading codes, and converts the CDMA signal into an optical signal by the optical transmitter having a carrier wavelength allocated by the OLT, wherein said OLT comprises: an optical receiver that receives a wavelength-division-multiplexed CDMA signal from said trunk optical fiber and outputs an output signal; and a plurality of despreaders connected to the optical receiver and different in their spreading code, each of the despreaders reproducing a CDMA signal corresponding to its spreading code from the output signal of said optical receiver, and wherein each of said ONTs has a flow identifier table indicating the correspondence between flow identifiers of transmission data and spreading codes, and said reception processing unit correlates said transmission data and said code-division spreader according to the flow identifier table.