Patent ID: 6731828
Filing Date: 2004-05-04
Classification: G02B

Abstract:
A waveguide-type optical signal processing circuit having lattice-form circuits each comprising optical couplers and delay circuits alternately cascaded together using optical waveguides each composed of a core formed on a substrate to guide signal light and a clad arranged around the core and having a lower refractive index than the core, the delay circuit being connected to the corresponding optical coupler and composed of two arms, the lattice-form circuit comprising an input waveguide connected to the leading optical coupler and an output waveguide connected to the trailing optical coupler connected to the last delay circuit,wherein the said series of lattice-form circuits are arranged in a form in which two spirals are combined together on said substrate so as not to cross each other and coupled together in the middle thereof, wherein said optical waveguides, each of which is composed of two arms, are arranged so as to extend halfway around said respective spirals, and wherein an end of the input waveguide which is not connected to said leading optical coupler and an end of the output waveguide which is not connected to said trailing optical coupler extend outward from said spirals.