Patent ID: 8270790

Claim:
A planar optical waveguide element comprising: a core of an optical waveguide; and a first Bragg grating pattern and a second Bragg grating pattern provided on the core, wherein: the first Bragg grating pattern and the second Bragg grating pattern are mutually parallel and extend along a propagation direction of guided light; the first Bragg grating pattern comprises recessed portions and protruding portions that are formed on both outer side walls of the core along the propagation direction of guided light; and the second Bragg grating pattern comprises at least one of: a projection that is formed in a top portion of the core, extending along a center of the width direction of the core in the propagation direction of guided; and a groove that is formed in a top portion of the core, extending along a center of the width direction of the core in the propagation direction of guided light.