Energy‐efficient bi‐directional visible light communication using thin‐film corner cube retroreflector for self‐sustainable IoT.

This study presents the design and analysis of energy‐efficient visible light communication‐based downlink and uplink using a thin‐film corner cube retroreflector (TCCR). The uplink establishment from the user device (UD) to base station (BS) is achieved with the retroreflection of the downlink light beams using TCCR in UD. It eliminates the requirement of active optical source in the UD that reduces the power consumption for communication from the battery‐constrained devices. Additionally, the photoelectric effect‐based energy harvesting from lighting sources is also incorporated in the UD. By utilising the thin‐film deposition of photosensitive alkali metals Na, K, Rb, and Cs, light energy has been harvested, and the harvested energy is utilised in the UD for the uplink modulation process. It makes the real self‐sustainable communication towards the battery‐less execution of internet of things (IoT). The proposed system offers the downlink and uplink for the distance of 2.15 m with the data rates of 10 Gbps and 1 kbps, respectively. The maximum harvested energy from the 18 W optical source by using the 100 nm Cs‐TCCR is 104.40 µJ, and it can serve the energy consumption of the uplink modulator to transmit the UD data to the BS. [ABSTRACT FROM AUTHOR]