Patent ID: 7590312

Claim:
An interferometer optical switch comprising an optical waveguide circuit including: a first optical multi/demultiplexing device; an optical delay line including two optical waveguides connected to said first optical multi/demultiplexing device; a second optical multi/demultiplexing device connected to said optical delay line; one or more input waveguides connected to said first optical multi/demultiplexing device; one or more output waveguides connected to said second optical multi/demultiplexing device; and a phase shifter installed in said optical delay line, and wherein at least one of said first optical multi/demultiplexing device and said second optical multi/demultiplexing device is a phase generating coupler which produces a wavelength-dependent phase difference; characterized in that assuming that λ is the wavelength, 2πφ 1 (λ) is the phase produced by the first optical multi/demultiplexing device, 2πφΔ L (λ) is the phase difference of the optical delay line with an optical path length difference of ΔL, and 2πφ 2 (λ) is the phase produced by the second optical multi/demultiplexing device, the sum of the phase difference 2π{φ 1 (λ) +φΔ L (λ)+φ 2 (λ)} is set at a constant value regardless of wavelength.