基于信息后处理的OAM态成分检测方法及应用

为了有效提升轨道角动量（OAM）态的检测效率，提出一种基于快速傅里叶变换（FFT）的OAM态成分检测方法.在马赫曾德尔干涉仪2臂上加入道威棱镜，其中一个道威棱镜设置为0，另一个道威棱镜设置为0~180°旋转，以接收干涉总光强，并对总光强进行FFT，从而在FFT域中提取OAM态的成分信息.数值仿真结果表明，该方法可有效地实施单个OAM态和复用OAM态的成分检测.不同于传统OAM态的检测方法，本方法可同时获取对FFT域设定子区间内总能量的判决.当该方法被应用于OAM通信系统时，能直接判决各OAM态信息，显著减小系统噪声对OAM复用通信性能的影响.

Detection of OAM State with Post Information Processing and Its Application in Communications

In order to effectively improve the detection efficiency of orbital angular momentum (OAM), we propose an OAM detection method based on post information processing. In the proposed detection method, a Mach-Zehnder interferometer is applied, and two doves are placed in each arm of the interferometer, where one is setup to 0 degree, and the other is rotated from 0 to 180 degree. The interference beam is received and the fast Fourier transform (FFT) is operated on the received signal. In the FFT domain, each OAM component is separated, named OAM spectrum. Numerical simulation results show that it is separable for one OAM mode, and multiplexed OAM mode by the proposed OAM detection method. Different from the general OAM separation method, the proposed method can obtain the OAM information by summarizing the total energy during a period in FFT domain. And the performance of the communication system can be improved by using this detection method.