Multichannel visible light communication and sensing system over a single optical path

GaN multiple-quantum well (MQW) diodes inherently exhibit overlapping emission and detection spectra, enabling them to function as both a transmitter and a receiver simultaneously. This dual functionality allows for bidirectional data transmission over a single communication channel via time-division multiplexing. In this work, we propose and experimentally demonstrate a multichannel visible light communication and sensing system over a single optical path, integrating blue and green MQW transmitter/receiver pairs with a micro-magnetic field sensor. Two blue MQW diodes, coated with distributed Bragg reflectors that reflect blue light while transmitting green light, are positioned between two green MQW diodes, thereby enabling multiple communication channels over a single optical path. All nodes are symmetric and decentralized, forming a fully bidirectional optical communication network. When the external magnetic field strength changes the refractive index of the magnetic fluids, the received light is thus modulated for realizing external magnetic field sensing. This work paves a feasible way to develop complete mapping all-light communication and sensing integrated networks for diverse applications.