Anguita Jaime A, Neifeld Mark A, Vasic Bane V
Department of Electrical and Computer Engineering, College of Optical Sciences,University of Arizona, Tucson, Arizona 85721, USA.
Appl Opt. 2008 May 1;47(13):2414-29. doi: 10.1364/ao.47.002414.
A multichannel free-space optical (FSO) communication system based on orbital angular momentum (OAM)-carrying beams is studied. We numerically analyze the effects of atmospheric turbulence on the system and find that turbulence induces attenuation and crosstalk among channels. Based on a model in which the constituent channels are binary symmetric and crosstalk is a Gaussian noise source, we find optimal sets of OAM states at each turbulence condition studied and determine the aggregate capacity of the multichannel system at those conditions. OAM-multiplexed FSO systems that operate in the weak turbulence regime are found to offer good performance. We verify that the aggregate capacity decreases as the turbulence increases. A per-channel bit-error rate evaluation is presented to show the uneven effects of crosstalk on the constituent channels.
研究了一种基于携带轨道角动量（OAM）光束的多通道自由空间光（FSO）通信系统。我们对大气湍流对该系统的影响进行了数值分析，发现湍流会导致通道间的衰减和串扰。基于一个组成通道为二元对称且串扰为高斯噪声源的模型，我们在研究的每个湍流条件下找到了OAM态的最优集合，并确定了这些条件下多通道系统的总容量。结果发现，在弱湍流 regime 下运行的OAM复用FSO系统具有良好的性能。我们验证了总容量会随着湍流的增加而降低。还给出了每个通道的误码率评估，以显示串扰对组成通道的不均匀影响。
