Patent ID: 6633703
Filing Date: 2003-10-14
Classification: G02B

Abstract:
An optical multiplexer/demultiplexer comprising:a substrate; first and second slab waveguides provided on said substrate, each having a predetermined slab length; a waveguide provided on said substrate, said waveguide being at least one input waveguide for guiding light into said first slab waveguide; waveguides flatly arrayed on said substrate in a state in which optical input ends of the respective waveguides are connected to an optical output end face of said second slab waveguide, said waveguides being a plurality of output waveguides provided corresponding to respective signals of channel wavelengths set as signal channels at predetermined wavelength intervals; waveguides flatly arrayed on said substrate in a state in which optical input ends of the respective waveguides are connected to an optical output end face of the first slab waveguide so as to place said first slab waveguide between said waveguides and said input waveguide and in which optical output ends of the respective waveguides are connected to an optical input end face of the second slab waveguide so as to place said second slab waveguide between said waveguides and said output waveguides, said waveguides being a plurality of channel waveguides of mutually different lengths; and a waveguide provided between said input waveguide and said first slab waveguide, said waveguide being a free propagation area comprised of a first portion having side faces which extend along respective predetermined curves so as to increase width from an optical output end of the input waveguide toward an optical input end face of the first slab waveguide, and a second portion provided between the first portion and the first slab waveguide and having width larger than that of the input waveguide; and wherein said predetermined curves are curves represented by exponential functions.