In our increasingly digitalized and interconnected world, the “Internet of Things (IoT)” is becoming more and more important. New applications are rapidly arising here for consumers, commerce, industry, infrastructure and the energy system. In most of these applications, there is a call for small and wireless devices with integrated sensors, which can simply be positioned anywhere. Two decisive factors in the development of such devices are the implementation of bi-directional communications and the power supply. Autonomous solutions for the latter task are interesting to enable truly self-sufficient operation without an external supply of energy. This means that neither cables nor batteries and their maintenance are needed. Alternatively, a wireless optical power supply that converts light from an external source can be implemented (Power-by-Light).