Multichannel Visible Light Communication over a Single Optical Path

Multiple-quantum-well (MQW) diodes have a variety of light emission, transmission, modulation, and detection functions. In particular, they feature an emission-detection spectral overlap region, allowing them to be used as both transmitters and receivers at the same time. Here, we vertically assemble red, green, and blue MQW diodes to create wavelength-division multiplexing (WDM) transmitters and receivers by using the distributed bragg reflector (DBR) technique. A single-link light communication system, in which longer-wavelength photons can pass through the shorter-wavelength MQW diode transmitter/receiver pair to prevent crosstalk from occurring between the different optical signals, is established to achieve bidirectional data transmission over more than one channel. With the appropriate optical system in place, it is possible to accurately transmit optical data over a range of 25 m. The system experimentally demonstrates real-time multichannel communication of information, including video and audio signals, over a single optical path. These results show that the vertical integration of MQW diodes offers a promising way to create a WDM visible light communication system.