The Simulated Method Of Phase Screen And Experimental Research On Optical Communication Links Of Mobile Platform

The laser communication of mobile platform shows a flourishing development trend.The laser communication links of various water based,land based,space-based and space-based mobile platforms have carried out a wide range of experiments showing an explosive growth,and optical communication shows a broad application prospect.However,these laser communication links will be affected by atmospheric turbulence.Because of the existence of such a bottleneck,the simulation of the laser communication will have some value,and the simulation of the laser atmospheric communication has little effect on the tracking error.Therefore,it is necessary to study the laser communication link of the large air channel and the mobile platform through the simulation and experiment.The effect of tracking error is integrated.In this paper,the influence of atmospheric and tracking errors on optical communication links is studied by two means of simulation and experiment.In the simulation,the tracking error is introduced on the basis of the static phase screen simulation and the simulation environment is established.In this environment,the corresponding scintillation index,the intensity fluctuation probability density function and the average bit error rate are discussed with the error rate as the core under the environment.Then the closed-loop tracking error is introduced and the detection error is introduced under the open loop aiming error.To discuss the change of the related parameters.In the experiment,the results of laser transmission in different atmospheric turbulence are realized by using the Zernike polynomial algorithm and the liquid crystal phase modulation of the spatial light modulator.The variation of speckle and the scintillation index of different turbulence intensity are analyzed.The results show that the phase amplitude of the phase screen increases with the intensification of the turbulence intensity.With the increase of the intensity of turbulence and the increase of the propagation distance,the speckle is divided,expanded and drifted,and the light intensity scintillation index increases.The results show that the phase fluctuation of the phase screen increases with the enhancement of the turbulence intensity in both simulation and experiment,and with the increase of turbulence intensity and the propagation distance,the light spots will split,expand and drift,and the intensity of light intensity is also increasing.With the increase of the opening pointing error,the change of the long period average light intensity distribution will gradually appear from the original Gauss type to its optical axis,and then appear in the vicinity of the optical axis.There is an exponential relationship between the total scintillation index and the tracking error and the relationship with the number of atmospheric scintillation fingers;the peak value of the light intensity.The peak value of the probability density function of the light intensity fluctuation decreases gradually,and the average error rate decreases with the mean signal to noise ratio,which further illustrates that the tracking error in the communication link of the mobile platform will have a certain influence on the performance of the optical communication link.After the closed-loop tracking error is added,the increase of the correction factor is more obvious to the correction of the open loop aiming error,the beam drift is restrained.Therefore,this paper establishes the phase screen simulation environment under the tracking error in the simulation part and lays the foundation for the follow-up performance research.In the experimental part,the setting up of the space light modulator to simulate the atmospheric turbulence phase screen in the experimental part is an important paving for the further research.