Influence Of Turbulent Atmosphere On Photon Acquisition And Dynamic Polarization Compensation

Laser satellite-ground communication is critical development branch in the field of future communications, it holds larger information capacity, smaller size of terminal, less power and good security advantages. Many countries have reached consensus on its potential and advantages, and increased research efforts. When the information transmission channel is turbulent random media, communication quality will be impact.Therefore, we shall overcome and compensate this impact.Firstly, this paper introduces the basis knowledge of light propagation in turbulent atmosphere, which includes causes of the turbulence, the statistical characteristics of turbulent random media, analytical and numerical simulation methods of light propagation in a turbulent medium and several atmospheric turbulent effects. In order to clearly understand the influence of turbulent atmosphere on photon acquisition, we start from Maxwell equations and utilize extended Huygens-Fresnel principle, the distribution equation of Gaussian beams photon acquisition probability through turbulent atmosphere is derived. On this basis, a analytic expression of axial acquisition solution is derived. Secondly, taking into account different factors as different turbulence intensity, different emission aperture and different wavelength, numerical solution for axial acquisition probability distribution is given by programming. Thirdly, the paper designs a set of experimental system and completed dynamic polarization compensation experiment, and introduces the specific function and procedures, experimental results have been discussed.The result indicates axial acquisition probability distribution shows cycle spiral structure under near-field mode and analyses relationships between rate of shocks and turbulence intensity,wavelength and emission aperture. Finds that acquisition probability will smoothly decline after reaching the last peak, analyses the factors influence the rate of decline and moment of peak. On the experimental side, through studying the optical subsystem and control subsystem, completed the design and debugging work, and discuss the result at last. The result indicates, the whole system is reliable and stable, the purpose of visualization input and output is achieved, and experiment of polarization tracking and compensation has been completed dynamic.