Photo-Luminescence Modulation Circuits for Solar Cell Based Optical Communications

High-efficiency solar cells, such as GaAs solar cells, exhibit strong luminescent emissions in the infrared. This paper presents two circuits that are able to modulate these luminescent emissions while harvesting energy from the solar cell. These circuits can be used in Internet-of-Things applications where devices need an energy source and a means to transmit information wirelessly. The proposed circuits are based on a boost DC-DC converter and are suitable for binary (on-off) modulation. These circuits require only minimal additional hardware (either a switch or an AND gate) for their implementation. Proof-of-concept prototypes of these circuits were built and tested. Experimental results show a tradeoff between harvested energy and bit error rate.