OPTICAL COMMUNICATION APPARATUS, OPTICAL COMMUNICATION SYSTEM AND OPTICAL COMMUNICATION METHOD

1 . An optical communication device comprising

an optical switch that is connected to a plurality of optical transmission lines and outputs an optical signal input from any of the optical transmission lines to another optical transmission line, and

a transferer configured to convert simplex transmission into duplex transmission or converts duplex transmission into simplex transmission between a subscriber device and the optical switch or between a first port of the optical switch to which the subscriber device is directly or indirectly connected and a second port opposite to the first port, and transfers the optical signal so as not to cause interference between uplink and downlink.

2 . The optical communication device according to claim 1 , wherein:

the transferer is a circulator;

the circulator includes a first port, a second port, and a third port;

the first port is connected to the subscriber device;

the second port is connected to an uplink first port among a plurality of first ports included in the optical switch;

the third port is connected to a downlink first port among the plurality of first ports included in the optical switch; and

the circulator outputs an optical signal input to the first port to the uplink first port connected to the second port, and outputs an optical signal input to the third port to the subscriber device connected to the first port.

3 . The optical communication device according to claim 1 , wherein:

the transferer is a circulator;

the circulator includes a first port, a second port, and a third port;

the first port is connected to a second port of the optical switch;

the second port is connected to an uplink optical transmission line;

the third port is connected to a downlink optical transmission line; and

the circulator outputs an optical signal input to the first port to the uplink optical transmission line connected to the second port, and outputs an optical signal input to the third port to the second port of the optical switch connected to the first port.

4 . The optical communication device according to claim 1 further comprising, on the side of the second port of the optical switch, a wavelength multiplexer/demultiplexer configured to multiplex or demultiplex an input optical signal, wherein

an uplink optical signal and a downlink optical signal are transmitted by simplex transmission.

5 . An optical communication system comprising:

an optical switch that is connected to a plurality of optical transmission lines and outputs an optical signal input from any of the optical transmission lines to another optical transmission line;

a transferer configured to convert simplex transmission into duplex transmission or converts duplex transmission into simplex transmission by multiplexing or demultiplexing an input optical signal between a subscriber device and the optical switch, and transfers the optical signal so as not to cause interference between uplink and downlink;

an uplink/downlink determiner configured to determine an uplink port and a downlink port among a plurality of ports included in the transferer on a basis of information on wavelengths used for the uplink and the downlink allocated to the subscriber device; and

an optical switch controller configured to control connection between ports of the optical switch according to a determination result of the uplink/downlink determiner.

6 . The optical communication system according to claim 5 , wherein

the optical switch controller controls the connection between the ports of the optical switch so that a port of the optical switch, to which a port of the transferer whose pass band is an uplink wavelength is connected, is connected to the uplink port, and controls the connection between ports of the optical switch so that a port of the optical switch, to which a port of the transferer whose pass band is a downlink wavelength is connected, is connected to the downlink port.

7 . An optical communication method comprising

connecting an optical switch to a plurality of optical transmission lines, the optical switch outputting an optical signal input from any of the optical transmission lines to another optical transmission line, and

converting simplex transmission into duplex transmission or converting duplex transmission into simplex transmission between a subscriber device and the optical switch or between a first port of the optical switch to which the subscriber device is directly or indirectly connected and a second port opposite to the first port, and transferring the optical signal so as not to cause interference between uplink and downlink.

8 . An optical communication method comprising:

connecting an optical switch a plurality of optical transmission lines, the optical switch outputting an optical signal input from any of the optical transmission lines to another optical transmission line;

a transferer converting simplex transmission into duplex transmission or converting duplex transmission into simplex transmission by multiplexing or demultiplexing an input optical signal between a subscriber device and the optical switch, and transferring the optical signal so as not to cause interference between uplink and downlink;

determining an uplink port and a downlink port among a plurality of ports included in the transferer on a basis of information on wavelengths used for the uplink and the downlink allocated to the subscriber device; and

controlling connection between ports of the optical switch according to a determination result.