The perfect optical vortex (POV) beam with the characteristic of the topological charge (TC)- independence radial profile is first considered to improve the spatial-mode-based underwater wireless optical communication (UWOC) performance. The evolution model of POV beams is proposed on the basis of Rytov approximation and the mutual coherence function to explore the impact of wave parameters on the orbital angular momentum (OAM) detection probability spectrum. The instantaneous crosstalk coefficients describing the POV-based UWOC systems are simulated by the multiple phase screen method with the signal coefficient modeled by a mixture Gamma-Gamma and normal distribution. A discrete and memoryless channel and a set of noncollaborative channels are modeled to obtain the capacity performances of the spatial-mode modulating and multiplexing systems, respectively. Results show the transmission quality of POV beams in oceanic turbulence is most related to the beam radius, while it is nearly free from the wavelength, TC, and radius-thickness ratio. Enjoying the advantage of the TC-independence beam radius, POV beams-based UWOC systems could achieve better bit error rate and capacity performances than the widely used Laguerre-Gauss beams when the higher-order TCs are adopted to modulate and multiplex information, which also confirms the superiority of POV beams in spatial-mode-based UWOC systems.

中文翻译：

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海洋湍流作用下完美涡旋光束的演化特性和空间模式UWOC性能


首先考虑具有拓扑电荷（TC）独立径向轮廓特征的完美光学涡旋（POV）光束来提高基于空间模式的水下无线光通信（UWOC）性能。基于Rytov近似和互相干函数，提出了POV光束的演化模型，探讨波参数对轨道角动量（OAM）探测概率谱的影响。描述基于 POV 的 UWOC 系统的瞬时串扰系数通过多相屏幕方法进行模拟，信号系数由混合 Gamma-Gamma 和正态分布建模。对离散无记忆信道和一组非协作信道进行建模，分别获得空间模式调制和复用系统的容量性能。结果表明，海洋湍流中POV光束的传输质量与光束半径关系最大，而与波长、TC和径厚比几乎无关。凭借与TC无关的光束半径的优势，当采用高阶TC来调制和复用信息时，基于POV波束的UWOC系统可以比广泛使用的拉盖尔高斯光束获得更好的误码率和容量性能，这也证实了 POV 光束在基于空间模式的 UWOC 系统中的优越性。