Photonic crystal waveguide
AssigneeNippon Telegraph and Telephone Corporation
InventorsMasaya Notomi, Koji Yamada, Akihiko Shinya, Junichi Takahashi, Chiharu Takahashi, Itaru Yokohama
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Abstract
A two-dimensional photonic crystal slab waveguide is provided in which a line defect is formed, wherein a first width which is a distance between centers of nearest two lattice points located on both sides of the line defect is different from a second width which is a corresponding distance in a normal two-dimensional photonic crystal slab waveguide. In addition, a two-dimensional photonic crystal slab waveguide is provided in which low refractive index columns in a optical waveguide part are placed at positions shifted from normal positions in a normal two-dimensional photonic crystal slab.
Claims17
A two-dimensional photonic crystal slab waveguide in which a part of holes in a lattice structure of a two-dimensional photonic crystal slab do not exist linearly so that a line defect is formed, wherein:
- a first width which is a distance between centers of nearest two lattice points located on both sides of said line defect is different from a second width which is a distance between centers of nearest two lattice points located on both sides of a line defect in a normal two-dimensional photonic crystal slab waveguide which simply lacks holes of a single line, wherein said first width is a value from 0.5 times to 0.85 times of said second width.
A two-dimensional photonic crystal slab waveguide in which a part of holes in a lattice structure of a two-dimensional photonic crystal slab do not exist linearly so that a line defect is formed, wherein:
- a first width which is a distance between centers of nearest-two lattice points located on both sides of said line defect is different from a second width which is a distance between centers of nearest two lattice points located on both sides of a line defect in a normal two-dimensional photonic crystal slab waveguide which simply lacks holes of a single line;
- wherein said first width is wider than said second width in which a single-mode appears in a high frequency side of a light line of cladding in a dispersion relation of waveguiding modes of said two-dimensional photonic crystal slab waveguide having said first width, and said first width is a value from 1.3 times to 1.6 times of said second width.
A two-dimensional photonic crystal slab waveguide in which dielectric cylindrical or polygon columns having lower refractive index than that of a dielectric thin-film slab are provided in said dielectric thin-film slab in a two-dimensional lattice pattern, and said dielectric thin-film slab is sandwiched by a top cladding layer and a bottom cladding layer which have lower refractive index than that of said dielectric thin-film slab, wherein:
- dielectric columns in an optical waveguide part in said two-dimensional photonic crystal slab waveguide are located at positions which are shifted in an optical propagation direction from positions at which said dielectric columns should be positioned in a normal two-dimensional photonic crystal slab.
Dependencies are inferred from the claim text.