大气湍流信道中OAM光束与高斯光束传输性能的实验研究

通过实验研究了大气湍流信道下中轨道角动量（OAM）光束与高斯光束的传输性能，并将两种光束的传输性能进行对比。实验以加载调制信号的OAM光束以及高斯光束为传输载波，分别测量了在大气湍流信道下两种光束的光束展宽、指向偏差、功率抖动以及误码率。实验结果表明:在大气湍流信道中传输后，OAM光束相比高斯光束，光束展宽减少10.5%，功率抖动的方差下降0.13，指向偏差的散布圆直径减小30.4%，并且光束中心更集中于接收面中心；OAM光束载波系统的最低探测灵敏度达到?28.97 dBm，相比高斯光束提升2.5 dB。实验结果证明了在大气湍流信道传输中，OAM光束比高斯光束受到湍流的影响更小，并且随着湍流强度的增加，OAM光束恶化程度远小于高斯光束。实验的结论为大气湍流信道下自由空间激光通信的发展和应用提供了参考。

Experimental research on transmission performance on OAM beam and Gaussian beam in atmospheric turbulence channel

The transmission performance of orbital angular momentum(OAM) beam and Gaussian beam in atmospheric turbulent channel was studied and compared experimentally. The beam spreading, pointing error, power jitter and bit error rate of the two beams were measured respectively, the OAM beam loaded with modulated signals and the Gaussian beam were as carrier. The experimental results show that in the atmospheric turbulence channel, compared with Gaussian beam, beam spreading ratio of the OAM beams reduces by 10.5%, variance of power jitter falls 0.13, dispersion circle diameter of the pointing error decreases by 30.4%, and more focused on the distribution of the center of the beam axis. The lowest detection sensitivity of the OAM beam carrier system reaches ?28.97 dBm, which improved 2.5 dB compared with that of Gaussian beam. The experimental results verify that OAM beam is less affected by turbulence than Gaussian beam in atmospheric turbulence channel, and the deterioration of beam quality of OAM beam is much less than Gaussian beam with the increase of turbulence intensity. The results of the experiment provide a reference for the development and application of free space laser communication in atmospheric turbulent channel.