Patent ID: 8391718

Claim:
A passive optical communication network system comprising: a first optical line termination unit for use in a communication station for transmitting on a first optical transmission line an optical signal carrying information of a plurality of channels encoded by optical code division multiplexing, and for decoding an optical signal supplied from the first optical transmission line to receive information of the plurality of channels; a second optical line termination unit for use at a subscriber site for transmitting and receiving the optical signal of one of the plurality of channels on a second optical transmission line; a first super-structured fiber Bragg grating (SSFBG) having a first one end and a first other end for receiving the encoded optical signal on the first one end to decode an optical signal of the one channel to output the decoded optical signal from the first one end, and to output an optical signal of channels other than the one channel from the first other end; a second SSFBG having a second one end and a second other end for receiving the optical signal of the one channel on the second one end to encode the optical signal of the one channel to output the encoded optical signal from the second one end, and for receiving the optical signal on the second other end to output the received optical signal from the second one end; a first circulator having first to fourth ports for receiving the optical signal on the first port from the first optical transmission line to output the received optical signal from the second port to the first one end of said first SSFBG, for receiving the decoded optical signal on the second port from the first one end of said first SSFBG to output the decoded optical signal from the third port to the second optical transmission line, for receiving the optical signal on the third port from the second optical transmission line to output the received optical signal from the fourth port to the second one end of said second SSFBG, and for receiving the encoded optical signal on the fourth port from the second one end of said second SSFBG to output the encoded optical signal from the first port to the first optical transmission line; and a second circulator having fifth, sixth and seventh ports for receiving the optical signal on the fifth port from the first other end of said first SSFBG to output the received optical signal from the sixth port, and for receiving the encoded optical signal on the sixth port to output the encoded optical signal from the seventh port to the second other end of said second SSFBG.