Y-BRANCHED OPTICAL WAVEGUIDE

PROBLEM TO BE SOLVED: To provide a Y-branched optical waveguide which demultiplexes or multiplexes a light to a main waveguide formed on a substrate, in which Y-branched optical waveguide a burying characteristic is improved and loss is decreased by optimizing the compatibility between the phase and the amplitude of light at a branched part. SOLUTION: In the branched optical waveguide composed of a tapered optical waveguide 11 formed at the end portion of an entrance waveguide 3 and emitting waveguides 5 and 6 which are arranged oppositely to the end face of the tapered optical waveguide 11 with a gap width Lg and adjacent to each other with a gap width Wg, the width of the end face of the tapered optical waveguide 11 is longer than the length which is a sum of the sum of the widths of the emitting waveguides 5 and 6 and the gap width Wg. COPYRIGHT: (C)2003,JPO