| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical multiplexer/demultiplexer using an array waveguide type diffraction grating, in which the passband characteristic of demultiplexed light is flattened at optimum condition with a structure of a low loss. SOLUTION: An optical input waveguide 2 and a sectrial slab waveguide 3 are connected with a directional coupler 21. The directional coupler 21 is composed of a central waveguide 21a which is composed of the emitting side end part of the optical input waveguide 2 and juxtaposed waveguides 21b and 21c which are provided on both sides of the central waveguide and the emitting end is connected to the sectrial slab waveguide 3. Taper parts are provided on both side parts of the central waveguide 21a so that the width of a core is gradually decreasing toward the emitting end and the end part is arranged not to be in contact with the sectrial slab waveguide 3. Further, the juxtaposed waveguides 21b and 21c respectively have a constant width of core, the equal numbers of the juxtaposed waveguides are arranged on both sides of the central waveguide 21a in parallel with the taper part of the central waveguide 21a, thus the light beams emitted from the central waveguide 21a are combined. COPYRIGHT: (C)2003,JPO |
