Research On Underwater Visible Light Communication System Based On GaN Vertical Structure LED

Visible light communication system research is of great significance to the requirements of special scenarios,such as the communication of underwater,battlefield anti-electromagnetic interference,data transmission in satellite cabin,optical interconnection in 6G,intelligence display and other key emerging technology fields.Taking the underwater communication for instance,most of the existing methods only use Sonar,which cannot transmit massive data and video images.Limited to the conflict of high-power and high-speed modulation of traditional LEDs,resulting in VLC are incapable of coming into service.The fabrication of LEDs and VLC systems with high-power,high-brightness and high-speed modulation deals with the problem of short-distance and high-speed underwater communication.As a supplementary means of Sonar,VLC plays a major role in promoting the exploration of Marine resources and defense capability.This thesis develops high-power LEDs based on Ga N vertical structure,and designs high-speed VLC system based on the underlying mechanism of them.In this thesis,the seawater channel is selected to analyze the key requirements of the underwater VLC.Secondly,Ga N-based vertical structure LEDs are fabricated according to the requirements,the photoelectric and communication parameters of LEDs are characterized by test platform,which lays a theoretical foundation for the subsequent VLC system.Finally,a high-speed VLC system with high-power for underwater,divided into transmitter,receiver,AGC and digital modulation,is designed on account of these parameters.The engineering prototype and performance test are completed as well.In this thesis,the experimental results and data show that Ga N vertical structure LEDs have a stable electrical power of 3W,and the optical power is greater than 60 m W with no lens package.A rate of 375Mbit/s at 16 QAM modulation of 0.3% and the 60 Mbps PRBS transmission are acquired.Meanwhile,the high-power VLC system based on the LEDs carries out 2Mbps FSK signal through a 10-meter water tank,where it completes the engineering test of full-duplex audio and video realtime communication.To conclude,the underwater VLC system based on Ga N vertical structure LED in this thesis is capable of effectively overcoming the short-range high-speed communication in special scenes.In fact,the thesis provides a reference for the follow-up research of high-power VLC.