通过数值仿真, 以多个相位屏模拟大气湍流, 研究大气湍流对轨道角动量(Orbital Angular Momentum, OAM)态复用通信系统质量的影响.改变大气湍流折射率结构常量C2n和传输距离z, 分析其对OAM态复用系统归一化接收功率、误码率等的作用.研究结果表明当大气湍流强度增加和传输距离增长时, 复用系统归一化接收功率下降、误码率增加.当C2n增大到5×10－13 m－2/3时, 系统归一化接收功率下降到0.2以下, 误码率增大到0.3以上; 当传输距离增大到10 000 m, 系统归一化接收功率下降到0.3以下, 误码率增大到0.35以上.同时, 对比不同方位角指数l取值的两个OAM态复用系统受大气湍流的影响, 发现: l取值越接近的系统, 受大气湍流影响越大.在等同光学信噪比下大气湍流导致OAM态复用系统误码率性能降低2至3个数量级.该研究对OAM态复用系统的实用化具有积极的参考作用.

The effects of turbulence aberrations on Orbital Angular Momentum (OAM)-multiplexed system by numerical simulation were analysed, where the turbulence aberration was simulated by several random phase screens generated by Kolmogorov model. The performances of normalized-received power and Bit Error Rate(BER) of the OAM-multiplexed system were characterized through changing the refractive index structure constant C2n and transmission distance z. The results show that normalized-received power decreases and the BER performance increases while the constant C2n and transmission distance z increases. The normalized-received power decreases to less than 0.2 and BER increases to more than 0.3 when the refractive index structure constant C2n is 5×10－13m－2/3. The normalized-received power decreases to less than 0.3 and BER increases to more than 0.35 while transmission distance z reaches 10 000 m. The comparison of the BER performance between two OAM-multiplexed systems with different values of the azimuthal index l is characterized. The results show that the OAM-multiplexed system which has closer values of l is more affected by atmospheric turbulence. At last, the BER with atmospheric tarbulence is decreased by two to three orders of magnitude compared with that one without atmospheric tarbulence at the same OSNR. The researchs have a good reference value for practical application of OAM-multiplexed system.