Photovoltaic laser power converters for wireless optical power supply of sensor systems

Abstract

Optical power transmission (also called power-by-light) is an elegant solution to power wireless sensor nodes. At the sensor, optical power in form of monochromatic laser light is converted to electricity by photovoltaic laser power converters. These photovoltaic cells are optimized for the monochromatic wavelength of the light — opposed to solar cells, where the cell is optimized for efficeint conversion of the entire solar spectrum. By fine-tuning the absorber material's bandgap to the photon energy thermalization losses can be minimized. Consequently, highest photovoltaic conversion efficiencies of up to 60 % can be achieved. One advantage of optical power transmission is the possibility to combine the power supply with optical communication in a single channel. There exist different ways to realize such combination. One interesting idea is the concept of combined transceiver devices for both optical power reception as well as data reception and transmission. This work gives an overview of latest achievements in the development of photovoltaic laser power converters, including results from various absorber materials for different wavelengths, cell architectures with increased output voltages, and combined power and data transceiver device architectures.