Patent ID: 7630602

Claim:
An optical filter module for wavelength multiplexing and demultiplexing, said module comprising: at least one input waveguide; an input-stage star coupler in the form of a slab waveguide connected to said at least one input waveguide; an array waveguide which is connected to said input-stage star coupler and in which a plurality of individual waveguides, each of which has an optical path having a predetermined length different to those of the other waveguides of the array and has a homogeneous waveguide interval formed of a core material having a first refractive index and a heterogeneous waveguide interval formed of core materials having said first refractive index and a second refractive index that is greater or less than said first refractive index, are sequentially arranged; an output-stage star coupler in the form of a slab waveguide connected to said array waveguides; and at least one output waveguide connected to said output-stage star coupler, wherein, in the heterogeneous waveguide interval, a core having a lesser refractive index is a clad of a core having a greater refractive index, and the optical path lengths of individual waveguides are different from each other in said homogeneous waveguide interval and said heterogeneous waveguide interval, respectively.