Patent ID: 8634679
Filing Date: 2014-01-21
Classification: G02B,G02F

Abstract:
1. An optical filter, comprising: a substrate; a plurality of looped waveguides provided on the substrate, each of which being configured as a closed loop; a first plurality of tunable couplers provided on the substrate, each of the first plurality of tunable couplers including a corresponding first portion of each of the plurality of looped waveguides, and a corresponding one of a first plurality of heaters, each of the first plurality of heaters being thermally coupled to the corresponding first portion of said each of the plurality of looped waveguides; and a second plurality of tunable couplers provided on the substrate, each of the second plurality of tunable couplers including a corresponding second portion of each of the plurality of looped waveguides, and a corresponding one of a second plurality of heaters, each of the second plurality of heaters being thermally coupled to the corresponding second portion of said each of the plurality of looped waveguides, each of the first plurality of tunable couplers being configured to adjust an amount of optical coupling between corresponding first adjacent ones of the plurality of looped waveguides, and each of the second plurality of tunable couplers being configured to adjust an amount of optical coupling between corresponding second adjacent ones of the plurality of looped waveguides, a first one of the first plurality of tunable couplers including a first Mach-Zehnder interferometer having first and second waveguides, which are spaced from one another, the first waveguide of the first Mach-Zehnder interferometer including a first part of a first one of the plurality of looped waveguides, and the second waveguide of the first Mach-Zehnder interferometer including a first part of a second one of the plurality of looped waveguides; and a second one of the first plurality of tunable couplers including a second Mach-Zehnder interferometer having first and second waveguides, which are spaced from one another, the first waveguide of the second Mach-Zehnder interferometer including a second part of the second one of the plurality of looped waveguides, and the second waveguide of the second Mach-Zehnder interferometer including a part of a third one of the plurality of looped waveguides.