The Research Of Adaptive Optical Technology Of OAM In Free Space Optical Communication Channel

In recent years,vortex beams with orbital angular momentum(OAM)aroused great interest of scholars,it has important research value and broad application prospects in the field of optical communications.We often use OAM beam transmitted through air channel to increase the data rate.Atmospheric channel is a time varying channel,absorption between the particles,flicker effect,which would cause loss of energy transmission beam and a phase change.Based on the conventional adaptive optics Shack Hartmann sensor repair scheme,we proposed rehabilitation program without adaptive optics wave front sensor for OAM beam distortion correction.And further investigate the effects of the impact on the repair function deformable mirror effect.Work and results are as follows.Firstly,studied under the influence of atmospheric turbulence OAM beam transmission characteristics for the distortion of beam structures OAM adaptive optics to repair the system no wave front sensor can be compensated.Adaptive optics rehabilitation program without wave front sensor mentioned herein without Shaq Hartmann wave front sensor slope information collected,there is no need to join the pilot beam,reducing the repair process and reduces repair costs.Secondly,research on adaptive rehabilitation program before no wave sensor,combined with stochastic parallel gradient descent algorithm(SPGD)for OAM beam distortion before and after the restoration phase diagram simulation analysis.Thirdly,affecting the function of the deformable mirror were analyzed,analyze the impact deformable mirror Gaussian index and cross-linked values change fitting accuracy,finding the optimal parameters of a deformable mirror,so that no wave front sensor adaptive optics repair system performance has been improved analysis.Fourthly,deformation mirror drive the number and arrangement,the influence of the number and arrangement of the drive to repair properties.It combined with image quality evaluation,error fit and optical power.Improve system performance to explore the best drive number and arrangement.In this paper,four points above research and analysis of the phase distortion OAM beam transmission in a turbulent correction.It made no wave front sensor adaptive optics rehabilitation program.It study analyzed the number of parameters change and drive the deformable mirror arrangement changes on correction effect for the orbital angular momentum and adaptive optics provides a new field thinking.