An optical switch is provided. The optical switch includes a substrate having a first surface and a second surface. At least one optical waveguide is formed below the first surface of the substrate. A heating element is disposed on the first surface of the substrate. The heating element is also disposed in proximity to the at least one optical waveguide. A cavity is formed in the second surface of the substrate. The cavity is also disposed in the proximity to the at least one optical waveguide. A heat conductive material is disposed within the cavity.