Optical Switching Devices Including Phase Transition Materials

An optical switching device includes a substrate having an optical waveguide thereon, and a phase transition pattern in or on a portion of the optical waveguide. The phase transition pattern includes a material that is configured to be switched between insulating and conductive states responsive to a stimulus. At least one conductive element on the substrate directly contacts the phase transition pattern to provide the stimulus to the phase transition pattern. Related fabrication methods are also discussed.