Patent ID: 6580862
Filing Date: 2003-06-17
Classification: G02B

Abstract:
An optical waveguide circuit including optical waveguides each of which has a cladding and a core formed on a substrate, whereinsaid optical waveguide circuit comprises at least one of a single-mode waveguide, a multi-mode waveguide and a slab waveguide, wherein at least one of said single-mode waveguide, said multi-mode waveguide and said slab waveguide includes at least in its part a multilayer structure that is composed of multiple types of layers with different refractive indices, and has at least three layers in total, wherein said multilayer structure has first birefringence and second birefringence, the first birefringence deriving from a fact that an effective refractive index of the entire core, which results from contributions of the layers to the refractive index, has different values in directions parallel to and perpendicular to the layers, and the second birefringence deriving from a structure of said waveguide, and wherein when defining a value of the birefringence of said waveguide as a value obtained by subtracting an effective refractive index in the direction parallel to the substrate from an effective refractive index in the direction perpendicular to the substrate, the value of the first birefringence and the value of the second birefringence have opposite signs.