Model-Based Wavefront Sensorless Adaptive Optics System for Multi-Ring Perfect Optical Vortex Beams

In free-space optical communication (FSOC) applications, multi-ring perfect optical vortex beams (MR-POVBs) exhibit significant advantages owing to their high-dimensional multiplexing capacity and stable beam profile. However, during transmission, they are susceptible to atmospheric turbulence, which induces wavefront distortion. Wavefront distortion interferes with the accurate identification of topological charges, thereby causing communication errors and limiting channel capacity. To address this problem, this paper proposes a model-based dual-path perfect vortex beam correction system without a wavefront sensor. The proposed system is theoretically founded on the linear relationship between the second-order moment of the wavefront gradient and the masked far-field intensity distribution, based on which a fast closed-loop control algorithm is designed. The simulation model adopts a 61-element deformable mirror (DM), an image sensor, and a common-path configuration of MR-POVBs and a reference plane wave. Simulation results demonstrate that the proposed method and system framework achieves rapid and stable wavefront correction for MR-POVBs under different turbulence intensities. The number of iterations required for system convergence only depends on the orders of selected Zernike modes, which significantly accelerates the convergence speed of the algorithm. This work confirms that the proposed system effectively mitigates the wavefront distortion of MR-POVBs and substantially improves the recognition accuracy of topological information, thereby providing a theoretical foundation and technical reference for the future practical application of MR-POVBs in free-space optical communication systems.