Characterization And Correction Of Wave-front Aberration In Laser Beam Propagating Over Water

The free space optical communication technology is suitable for the transmission of information in the marine environment,but the ocean atmosphere severely limits the performance of the system.In order to reduce the influence of the ocean atmosphere on the free space optical communication system,it is necessary to study the wavefront distortion of the laser beam above water and design a reasonable control algorithm to correct the wavefront distortion.In this paper,the characterization and correction techniques of wavefront distortion of the laser beam above water are studied,and the accurate measurement and reconstruction of the wavefront distortion of the laser beam are realized.The dynamic characteristic modeling and controller design of the adaptive optical system are carried out.The design of the ocean atmospheric turbulence simulation device and adaptive optical system experimental platform are achieved.Based on the measure and reconstruct the wavefront distortion of the laser beam,the change characteristics of the wavefront distortion of the laser beam after different heating time using different heating devices are studied.Then,according to the input and output data of the adaptive optical system,a dynamic model of the adaptive optics system is established.Based on the model,the closed-loop controller of the adaptive optics system is designed and realized.Finally,the real-time correction of the wavefront distortion of the laser beam subjected to atmospheric turbulence disturbance is achieved by using the closed-loop adaptive optical system,which effectively reduces the wavefront distortion of the beam and verifies the system performance.The feasibility of using the dynamic coupling model to correct the wavefront distortion of the laser beam is verified,which has laid a foundation for the application of adaptive optics in the marine environment.The research results can be used to improve the communication quality of the free space optical communication system in the marine environment.