Patent ID: 11956009
Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Field: Telecommunications (Electrical engineering)
Classification: CPC H | IPC H

Claim 3:
4. The optical communication system according to claim 1, wherein
the unequal branch optical splitter includes
a cross-linking branch optical circuit that is a waveguide optical splitter having two inputs and two outputs, in which one of the two inputs of the waveguide optical splitter is connected to the primary-side main port, and one of the two outputs of the waveguide optical splitter is connected to the secondary-side main port, and
an unequal branch optical circuit connected to the other of the two inputs of the waveguide optical splitter and another unequal branch optical circuit connected to the other of the two outputs of the waveguide optical splitter, and
the unequal branch optical circuit
connects one multiplexing port Px connected to the cross-linking branch optical circuit and m pieces of demultiplexing ports Py1 to Pym, where m is an integer of two or more, by using m−1 pieces of the waveguide optical splitters having two inputs and two outputs combined,
the multiplexing port Px is connected to one of two inputs of a first stage of the waveguide optical splitter, and one of two outputs of the first stage of waveguide optical splitter, which is directly connected to the multiplexing port Px via a waveguide, is set to a first demultiplexing port Py1,
one of two outputs of a (k−1)th stage of the waveguide optical splitter, which is not connected to a demultiplexing port Py(k-1), is connected to one of two inputs of a kth stage of the waveguide optical splitter, where k is an integer from two to m−2, and one of two outputs of the kth stage of the waveguide optical splitter, which is directly connected to the (k−1)th stage of the waveguide optical splitter via a waveguide, is set to a kth demultiplexing port Pyk, and
one of two outputs of an (m−2)th stage of the waveguide optical splitter, which is not connected to a demultiplexing port Py(m-2), is connected to one of two inputs of an (m−1)th stage of the waveguide optical circuit, one of two outputs of the (m−1)th stage of the waveguide optical splitter, which is directly connected to the (m−2)th stage of the waveguide optical splitter via a waveguide, is set to an (m−1)th demultiplexing port Py(m-1), and the other of the two outputs is set to a demultiplexing port Pym,
where the (m−1)th stage of the waveguide optical splitter is provided when m is three or more, and the kth waveguide optical splitter is provided when m is four or more.