Patent ID: 7027690

Claim:
An optical waveguide coupler circuit device comprising: a substrate; a polymeric lower cladding layer formed on the substrate; at least two polymeric optical waveguides formed on the polymeric lower cladding layer; a polymeric upper cladding layer covering the optical waveguides; and plural directional couplers which are obtained by choosing any pair from the at least two optical waveguides, and bringing them close to each other at plural sites, wherein: each of the optical waveguides has two ends, one end serving as an input terminal and the other as an output terminal; the two paired optical waveguides are configured such that the difference between their effective optical paths spanning between arbitrarily chosen adjacent directional couplers is defined as ΔL, and ΔL=0.7 to 0.9 μm; each of the plural directional couplers comprises a parallel section at which the two optical waveguides are disposed in parallel with each other; and the polymeric optical waveguide is made from a polymer having a refractive index of 1.508 to 1.568 and a birefringence of 0.008 to 0.01.