Patent ID: 7580597

Claim:
An optical functional circuit in which a plurality of circuit elements are formed on a substrate, comprising: a wave propagation medium for converting an optical path of a leakage light that is not emitted from a predetermined output port of the circuit element so as to prevent the leakage light from being coupled to a different circuit element, wherein the wave propagation medium comprises an optical waveguide, which is provided with a clad layer formed on the substrate and a core embedded in the clad layer, and the wave propagation medium has a spatial refractive index distribution for outputting the leakage light launched into the circuit element to other port as output-light with multiple scattering through the wave propagation medium, said spatial refractive index distribution is designated by each refractive index of pixels defined by a mesh, said each refractive index of the pixels is determined by calculating a phase difference between a forward propagation of the input field of the leakage light and a reverse propagation of the output field of the output-light at each pixel and repeating calculations until said phase difference becomes less than a desired value.