Full-duplex visible light communication system using a single channel

Abstract

Multiple quantum well (MQW) III-nitride diodes can emit light and detect light at the same time. In particular, given the overlapping region between the emission spectrum and the detection spectrum, the III-nitride diode can absorb photons of shorter wavelengths generated from another III-nitride diode with the same MQW structure. In this study, a wireless visible light communication system was established using two pairs of identical III-nitride diodes with different wavelengths. In this system, two green light diode chips were used to transmit and receive green light signals on both sides. We have integrated two blue light chips with optical filtering in the middle of the optical link to carry out blue light communication, with one end transmitting and one end receiving. Simultaneously, green light was allowed to pass through two blue light chips for optical communication. Combined with a distributed Bragg reflection (DBR) coating, we proposed using four chips in one optical path to carry out optical communication between chips with the same wavelength and used the coating principle to gate the optical wavelength to filter the clutter of green light chips on both sides to make the channel purer and the symbols easier to demodulate. Based on this multifunctional equipment, advanced single-optical path, III-nitride, full-duplex optical communication links can be developed for the deployment of the Internet of Things.