Zhao S M, Leach J, Gong L Y, Ding J, Zheng B Y
Institute of Signal Processing and Transmission, Nanjing University of Posts and Telecommunications, Nanjing, China.
Opt Express. 2012 Jan 2;20(1):452-61. doi: 10.1364/OE.20.000452.
The effect of atmosphere turbulence on light's spatial structure compromises the information capacity of photons carrying the Orbital Angular Momentum (OAM) in free-space optical (FSO) communications. In this paper, we study two aberration correction methods to mitigate this effect. The first one is the Shack-Hartmann wavefront correction method, which is based on the Zernike polynomials, and the second is a phase correction method specific to OAM states. Our numerical results show that the phase correction method for OAM states outperforms the Shark-Hartmann wavefront correction method, although both methods improve significantly purity of a single OAM state and the channel capacities of FSO communication link. At the same time, our experimental results show that the values of participation functions go down at the phase correction method for OAM states, i.e., the correction method ameliorates effectively the bad effect of atmosphere turbulence.
大气湍流对光的空间结构的影响损害了自由空间光（FSO）通信中携带轨道角动量（OAM）的光子的信息容量。在本文中，我们研究了两种用于减轻这种影响的像差校正方法。第一种是基于泽尼克多项式的夏克-哈特曼波前校正方法，第二种是特定于OAM态的相位校正方法。我们的数值结果表明，尽管两种方法都显著提高了单个OAM态的纯度和FSO通信链路的信道容量，但特定于OAM态的相位校正方法优于夏克-哈特曼波前校正方法。同时，我们的实验结果表明，在特定于OAM态的相位校正方法中，参与函数的值下降，即该校正方法有效地减轻了大气湍流的不良影响。
