Research of Phase Compensation Methods Based on the Median Reweighted Wirtinger Flow Algorithm

Abstract

An improved non-convex optimized phase recovery algorithm is used to compensate for wavefront aberrations caused by atmospheric turbulence and pointing errors in the vortex beam. The algorithm is divided into two parts: initialization and iteration. To reduce the effect of outliers, truncation rules are formulated in the initialization phase using the robustness of the sample median to obtain an initial value that is close to the global optimum. The relationship between the results of adjacent iterations is used in the iterations to calculate new weight coefficients, which are applied to the gradient descent to ensure the accuracy of the recovery results. Simulation experiments are carried out for different channel environments and different modes, and the results show that the improved phase recovery algorithm can accurately compensate for distorted wave fronts. The improved algorithm recovers the best results at different turbulence intensities and under the influence of different pointing errors. The recovered Strehl ratio can reach 0.9 and the mode purity can reach 0.92. Single-mode and multi-mode simulations were carried out, and the results show that the improved algorithm is effective and robust.

Keywords

• orbital angular momentum
• phase compensation
• non-convex optimization
• sample median
• reweighted