Abstract: A relay system includes a transmission device and a reception device. The transmission device includes: a first optical transmitter that converts a first signal to a first optical signal having a transmission speed equal to that of the first signal, and transmits the first optical signal; a data separator that converts the first signal to a plurality of low-rate signals having a lower speed than the first signal; a plurality of second optical transmitters each capable of converting the low-rate signals to low-rate optical signals and transmitting the optical signals, and converting a second signal to a second optical signal having a transmission speed equal to that of the second signal and transmitting the optical signal; and a multiplexer that multiplexes a plurality of optical signals selected from among the first optical signal, the low-rate optical signals, and the second optical signal, and outputs a multiplexed optical signal.

Abstract: An optical network unit according to one manner of the present invention includes an optical transceiver configured to be connected to an optical communication line, a plurality of media access control (MAC) processing units, a plurality of user network interface (UNI) ports each connected to one MAC processing unit of the plurality of MAC processing units, and an integration unit integrating a plurality of communication paths connected to the plurality of MAC processing units, respectively, and connected to the optical transceiver.

Abstract: An optical network unit according to one manner of the present invention includes an optical transceiver configured to be connected to an optical communication line, a plurality of media access control (MAC) processing units, a plurality of user network interface (UNI) ports each connected to one MAC processing unit of the plurality of MAC processing units, and an integration unit integrating a plurality of communication paths connected to the plurality of MAC processing units, respectively, and connected to the optical transceiver.

Abstract: An optical signal repeater, an optical communication system, and a method of repeating an optical signal capable of decreasing a difference in transmission time period due to a difference in transmission distance of an optical signal between an optical line terminal and a plurality of optical network units connected through branched communication paths are provided. An optical signal repeat is an optical signal repeater for repeating an optical signal transmitted between an optical line terminal and a plurality of optical network units connected through branched communication paths. The optical signal repeater includes a delay element. The delay element is provided between the ONU connected to the OLT through a shortest communication path among the branched communication paths and the OLT and delays transmission of the optical signal transmitted through the shortest communication path.