A thermal-optical phase shifter includes a substrate layer, a cladding layer, and a beam in the cladding layer. The thermal-optical phase shifter includes a waveguide and a heating element disposed in the beam. The thermal-optical phase shifter includes a thermally conductive structure disposed on the cladding layer to disperse heat from the beam. The thermally conductive structure may include a metal strip disposed longitudinally along the beam, may include thermally conductive pads, and/or may include thermally conductive vias coupled between the cladding layer and the substrate layer. The thermal-optical phase shifter may be incorporated into light detection and ranging (LIDAR) devices, telecommunications devices, and/or computing devices.