Research on adaptive receiving technology for atmospheric laser communication

The random fluctuation characteristics of the atmospheric channel are the key factors affecting the frequency band utilization and communication bit error rate of the laser communication system. Aiming at the application requirements of lightweight, low power consumption and low complexity of the atmospheric laser communication system, this paper proposes an adaptive optical information reception method. The turbulent scintillation index of the atmospheric channel received in real-time is used as a feedback quantity to establish a mapping model between the APD gain factor and the average bit error rate, and the optimal gain factor under different scintillation indices is obtained by taking the derivative of the mapping model. Simulation results show that the average BER of the atmospheric channel can be 10-7 by modulating the gain factor when the scintillation index less than0.05, The average BER decreases and then increases with the gain factor, and the optimal gain factor, Mo, ranges from 30 to 38. Designing an adaptive receiver communication scheme and completing an atmospheric laser communication experiment with a link distance of 1.1 km and a communication rate of 2.5 Gbps.The results show that an adaptive receiver system based on the optimal gain factor improves the communication BER in medium-weak turbulence channel.