Patent ID: 8355611

Claim:
A photonic crystal element, comprising: a photonic crystal, wherein said photonic crystal has a periodic lattice, said periodic lattice being a square lattice, said periodic lattice being a lattice of dielectric pillars having a high refractive index and being disposed in a medium having a relatively low refractive index; a first waveguide within the photonic crystal, said first waveguide including a first defect within said periodic lattice, wherein said first defect comprises a dielectric pillar having a small cross-sectional area compared to a cross-sectional area of a non-line defect pillar of the photonic crystal, said first waveguide being able to guide a light whose frequency is within a band gap of the photonic crystal; and a waveguide stub connected to control the light within the first waveguide, said waveguide stub being a waveguide including a tapered structure, extending perpendicularly from a side wall of the said first waveguide, and including at least one second defect within the periodic lattice, wherein said second defect comprises a dielectric pillar having a small cross-sectional area compared to a cross-sectional area of a non-line-defect pillar of the photonic crystal.