轨道角动量(OAM)作为一个全新的通信复用维度,在大气激光通信、卫星通信等领域有着广泛的应用价值。主要采用双路多进制OAM调制进行信息的传输,利用两路多进制信号产生具有不同拓扑荷值的涡旋光束再进行相干叠加,产生不同的光强图案,在接收端利用CCD相机记录下光强信息,通过光强信息可以识别不同的符号信息。采用双路四进制信息传输时,可以产生16种不同的光强图案,为了保证光强图案的差异性,提出了一种基于光强相关性的编码方案,同时探索了大气湍流对光强的影响。使用卷积神经网络(CNN)进行光强信息的识别,能够显著提高大气湍流影响下光强信息的识别率。

Orbital angular momentum (OAM), as a new communication multiplexing dimension, has a wide range of applications in the fields of atmospheric laser communication and satellite communication. Here, dual-channel multiband OAM modulation is explored as a means of information transmission. Two-channel multiband signals are used to generate vortex beams with different topological charge values for coherent superposition to produce different light intensity patterns. These patterns are recorded by a charge-coupled device (CCD) camera at the receiving end, where differences in light intensity information denote differences in symbol information. When dual-channel quaternary information is transmitted, 16 different light intensity patterns can be generated. To ensure the differences among light intensity patterns, a coding scheme based on light intensity correlation is proposed. The effect of atmospheric turbulence on light intensity pattern recognition is then explored. The use of a convolutional neural network (CNN) for light intensity information recognition is found to significantly improve the recognition rate of light intensity information under the influence of atmospheric turbulence.