Experimental research on phase diversity method for correcting vortex beam distortion wavefront

The orbital angular momentum (OAM) of the vortex beam has infinite dimension and are orthogonal to each other. OAM multiplexing technology is one of the key technologies to improve the channel capacity of wireless optical communication system. When the vortex beams propagate in atmospheric turbulence, it will cause wavefront distortion. The phase diversity (PD) method is used to obtain the phase information by inversely extracting the intensity information of the focal plane and the defocus plane, and realize the correction of the vortex beam distortion wavefront. The simulation and experimental results show that the relative powers of the single-mode and multi-mode multiplexed vortex beams can be effectively improved using the PD method to correct the distortion wavefront. The crosstalk between modes is reduced, and the correction effect increases with the decrease of topological charge.