Photovoltaic Cells with Increased Voltage Output for Optical Power Supply of Sensor Electronics

An elegant solution for the power supply of sensor electronics is the application of power-by-light technology. With this technology several challenges related to conventional copper wiring are inherently overcome; benefits are galvanic isolation, the suppression of electromagnetic interference, and the possibility to combine power and bidirectional data transmission in a single fiber link. In order to power sensor electronics efficiently, a supply voltage in the range 3 to 12 V is typically required. This paper deals with the photovoltaic laser power converter used to convert the transmitted optical power back into electricity. The advanced cell concepts of multi-junction and multi-segment cells are discussed which both aim at an increased output voltage on the device level, thereby eliminating the need for additional DC/DC conversion. Modeling and experimental results of GaAs based cells are presented, namely of single-junction 2- to 12-segment cells as well as of a dualjunction single-segment structure. A discussion of the pros and cons of the different concepts is given, focusing on the consequences of misalignment and temperature changes.