In an embodiment, a system includes an internal optical power transmitter configured to be disposed within a living subject. The internal optical power transmitter includes a power source configured to provide electrical energy and an electrical-optical converter operably coupled to the power source. The electrical-optical converter may be configured to convert at least a portion of the electrical energy into one or more optical power signals transdermally transmittable out of the living subject. The system further includes an external optical-electrical converter configured to convert the one or more optical power signals into one or more electrical power signals and at least one external device configured to be operably coupled to the external optical-electrical converter and powered by the one or more electrical power signals. Embodiments of methods, biocompatible electrical-optical converters, and internal optical power transmitters are also disclosed.