Research On InGaN Multiple Quantum Well Optoelectronic Devices For Visible Light Communication

With the emergence of wireless communication bottlenecks,visible light communication has entered people's eyes,and LEDs are widely used in visible light communication because of their fast response,low power consumption,and fast response.GaN-based photonic structures are of great interest for integrated optoelectronic devices in the visible region due to their capabilities of emission,transmission,modulation and detection.InGaN/GaN multiple quantum well diodes exhibits broadband emission.Hence,the MQW-diode can respond in the short wavelength half of the emission spectrum when it works as a photodiode.In this paper,the spatial simultaneous light-emitting light-detecting functionality of multiple quantum wells are studied,and the GaN-based visible light communication chip on silicon substrate is successfully realized.The main work results are as follows:In this paper,we build an on-chip photonic integration system on a GaN-on-silicon platform,both emitter and detector can be produced on the same substrate using the same fabrication processes.Using silicon removal and back wafer etching techniques,the emitter,waveguide and detector are integrated on a suspend membrane,forming the on-chip visible light communication system.The visible light communication chip on the GaN-on-silicon platform includes two suspended InGaN/GaN multiple-quantum-well diodes(MQWDs),which are connected by suspended waveguides.When two MQWDs are fabricated as a transmitter and a receiver,respectively,an in-plane one-way visible light communication system is formed,and the transmission rate is up to 100 Mbps.When two MQWDs are used as the light source and the detector,simultaneously,an in-plane simultaneous full-duplex communication system is formed,and the transmission rate is up to 1 MHz;when one of the MQWDs is used as a transmitter and externally received by a commercial detector,an out-of-plane one-way visible light communication system is formed,and the transmission rate reaches 120 Mbps.Here,spatial simultaneous light-emitting light-detecting functionality,in which the detected light comes form an external light source,is experimentally demonstrated.A micro-transmittance setup is built to collimate the emitting light and to focus the light onto the MQW-diode.The MQWD detects the spatial signal size under different bias voltages,that is,with the light emission intensity increase.InGaN/GaN multiple quantum well diodes as optoelectronic devices,under this spatial light-detecting mode,they can fully realize full-duplex visible light communication,and can be widely used in automatically adjustable displays and photonic chips in the future.