为了研究大气湍流对高斯涡旋光束传递信息的影响, 理论分析了经过大气湍流的高斯涡旋光束轨道角动量（OAM）模式的径向平均功率和归一化平均功率分布、固有模式指数、初始光束半径和湍流强度; 采用纯相位扰动逼近的有效性, 数值模拟高斯涡旋光束在传输中的OAM模式径向平均功率分布的变化。建立传输模型并进行外场激光大气传输实验, 对比分析了模拟和实测的OAM归一化平均功率分布, 结果表明在弱湍流条件下, OAM模式的径向平均功率随着接收器孔径尺寸的增加而变化, 逐渐趋于稳定值。对于一般常用的接收孔径, 在强湍流或较小的初始光束半径条件下对OAM模式干扰十分严重。验证了用数值方法模拟OAM在湍流介质中的模式变化过程的可靠性。

In order to research the influence of Gaussian vortex beam transmission on atmospheric turbulence, the radial average power and normalized average power distribution of the Gaussian vortex orbital angular momentum(OAM) states after atmospheric turbulence as well as the intrinsic mode index, initial beam radius and turbulence intensity were theoretically analyzed. The validity of pure phase perturbation approximation was used to numerically simulate the variation of radial average power distribution of OAM mode during the transmission of Gaussian vortex beam. The transmission model was established and the atmospheric laser field transmission experiments were conducted. The simulated and measured OAM normalized average power distributions were compared. The results show that under the condition of weak turbulence, the radial average power of OAM mode changes with the increase of receiver aperture size, and tends to be stable. For the common receiver aperture, the interference with OAM mode is very serious under strong turbulence or small initial beam radius. The reliability of numerical simulation of the mode change of OAM in turbulent media is verified. The paper also verifies the reliability of numerical simulation of the mode change of OAM in turbulent media.