Patent ID: 7590327

Claim:
A waveguide, comprising: a three-dimensional photonic crystal having a plurality of line defect members, wherein said three-dimensional photonic crystal includes a first layer in which a plurality of columnar structures are arrayed with a spacing, a second layer in which a plurality of columnar structures extending in a direction perpendicular to a direction along which the columnar structures of the first layer extend are arrayed with a spacing, a third layer in which a plurality of columnar structures extending in the same direction as the columnar structures of the first layer are arrayed with a spacing, and a fourth layer in which a plurality of columnar structures extending in the same direction as the columnar structures of the second layer are arrayed with a spacing, wherein the columnar structures of the first and third layers are mutually deviated by a half of the spacing in a direction perpendicular to the direction in which the columnar structures extend, while the columnar structures of the second and fourth layers are mutually deviated by a half of the spacing in a direction perpendicular to the direction in which the columnar structures extend, wherein the line defect members include a first line defect member made of a medium having a refractive index not smaller than that of the columnar structures and formed in a direction perpendicular to the direction in which the columnar structures extend, and a second line defect member formed in the same direction as the first line defect member.