| 摘要 |
PROBLEM TO BE SOLVED: To provide a multimode interference optical coupler in which an effect given to operation characteristics caused by dimension error produced in a manufacturing process is small, a whole length thereof is short and meandering of output light can be prevented. SOLUTION: The multimode interference optical coupler includes: first input/output optical waveguide part 200 and second input/output optical waveguide part 250; a first multimode optical waveguide part 210; a second multimode optical waveguide part 220; a fourth multimode optical waveguide part 230; and a third multimode optical waveguide part 240. The second multimode optical waveguide part has a width which continuously spreads from a boundary B<SB>2</SB>toward a boundary B<SB>3</SB>. The third multimode optical waveguide part is constituted of a first sub-multimode optical waveguide 242 and a second sub-multimode optical waveguide 244. The sub-waveguides have widths which become continuously narrow from the boundary B<SB>3</SB>toward a boundary B<SB>4</SB>. The first input/output waveguide part is constituted of a first sub-optical waveguide 202 and a second sub-optical waveguide 204. Center axes of the sub-optical waveguides are set on the positions deviated from the center axis of the first multimode optical waveguide part. COPYRIGHT: (C)2008,JPO&INPIT |
