Research on the Dichroic Demultiplexing Method in RGB-LED Visible Light Communication System

Nowadays, LED has been used as a signal source of visible light communication system more widely, in the research of visible light communication technology, in order to obtain better lighting experience and higher data transmission rate, RGB-LED can used as the light source. Aiming at the demultiplexing problem of receiver in RGB-LED visible light communication system, a dichroic demultiplexing method based on dichroic mirrors is given in this paper. Firstly, the problem of light energy loss by the filter demultiplexing method that is conventionally used in RGB-LED visible light communication system is analyzed, and then a new dichroic demultiplexing unit is designed based on dichroic mirrors. Then optical structure of the dichroic demultiplexing unit and the generally used filter demultiplexing unit are simulated respectively by optical simulation software Tracepro, and the performance of the two demultiplexing methods has been compared. The result shows that compared with the system using filter demultiplexing method, the system using dichroic demultiplexing method can improve the light energy reaching the receiving surface nearly two times. Finally, the simulation analysis of communication performance is carried out, and the relationship between the bit error rate and the communication distance of two solutions is studied respectively. Simulation results show that, under the same bit error rate conditions, using the dichroic demultiplexing method can effectively extend the transmission distance of RGB-LED visible light communication system compared with the filter demultiplexing method. This paper provides a new implementation scheme for demultiplexing in RGB-LED visible light communication technology research.