Patent ID: 8064490

Claim:
An optical resonator comprising: a Y-branched waveguide including first, second, and third optical waveguides with respective initial ends and respective terminal ends, the respective initial ends being interconnected at a single point, each of the second and third optical waveguides including at least one wavelength selector; a reflector facing the terminal end of the first optical waveguide; and an optical connecting path coupling the terminal end of the second optical waveguide to the terminal end of the third optical waveguide, the optical connecting path including a loop optical waveguide optically coupled to the terminal end of the second optical waveguide and the terminal end of the third optical waveguide, the loop optical waveguide including a first part disposed adjacent to the terminal end of the second optical waveguide to form a directional optical coupling with the second optical waveguide, and a second part disposed adjacent to the terminal end of the third optical waveguide to form a directional optical coupling with the third optical waveguide, wherein the at least one wavelength selector comprises n Mach-Zehnder interferometers, n being an integer greater than two, each one of the n Mach-Zehnder interferometers having two arms, the two arms of the i-th one of the n Mach-Zehnder interferometers differing in optical path length by a quantity ΔLi (i varying from 1 to n), one of the two arms of the i-th one of the n Mach-Zehnder interferometers having an electrode of length Lei, the quantities ΔLi and Lei doubling in each successive Mach-Zehnder interferometer, so that: Δ Li=ΔL 1×2 i−1 Lei=Le 1×2 i−1 , wherein the first n−1 ones of the n Mach-Zehnder interferometers are disposed on the second optical waveguide and the n-th one of the n Mach-Zehnder interferometers is disposed on the third optical waveguide.