Optical Wireless Power Transmission Using Si Photovoltaic Through Air, Water, and Skin

Optical wireless power transmission has many possible applications in daily life, such as for supplying power to unmanned autonomous vehicles and charging implantable medical devices. System efficiencies of optical wireless power transmissions through atmosphere, water, optical fiber, and human skin are numerically calculated and analyzed. Silicon photovoltaic is used as the optical-to-electrical power converter. By assuming that the electrical-to-optical power conversion efficiency of laser diode to be 40% and does not have wavelength dependency, it is found that maximum system efficiency of 22.1% at 940 nm and 1.36% at 960 nm for 1-km distance power transmission through air with 30-km visibility and 1-km visibility, respectively, can be achieved while for optical power transmission through water, system efficiency around 5.5% at 400 nm for 100-m depth of water. For the optical power transmission through skin, the maximum system efficiency for 2-mm thickness of human skin is 14% at 910-nm wavelength.