Patent ID: 6873769

Claim:
An optical waveguide coupler, comprising: a micro-cylinder resonator which is in contact with a plurality of optical waveguides and has a wavelength discrimination function, wherein the micro-cylinder resonator is sandwiched between two optical circuit boards each carrying a plurality of optical waveguides such that guided light propagating through each optical waveguide of one optical circuit board and having a wavelength satisfying the resonance condition of the micro-cylinder resonator propagates via the micro-cylinder resonator to the corresponding optical waveguide of the other optical circuit board and exits from an output end of the corresponding optical waveguide, and that, by utilization of a size effect attained through size reduction of the micro-cylinder resonator, influence of the micro-cylinder resonator is reduced under a nonresonance condition, and a condition for phase matching between a guided mode of the optical waveguide and that of the micro-cylinder resonator is relaxed under a resonance condition, and wherein the micro-cylinder resonator is disposed in contact with a multimode optical waveguide in order to provide a function of a notch filter which reduces a zero intensity of light transmitted to a specific mode that satisfies the resonance condition of the multimode optical waveguide and the micro-cylinder resonator.