Xu Guanjun, Lai Jiahui
Appl Opt. 2020 Mar 10;59(8):2551-2558. doi: 10.1364/AO.382628.
Underwater optical communication has been a promising technology but is severely affected by underwater turbulence due to the resulting fluctuations in the index of refraction. In this paper, a revised spatial power spectrum model is obtained that considers the refraction index to be a function of the eddy diffusivity ratio, assuming the underwater turbulence is anisotropic. The scintillation indices for both plane and spherical waves that propagate in underwater turbulence are derived based on this model. Thereafter, the performance of an optical communication system, i.e., the outage probability and bit error rate, with the associated aperture averaging effect is considered. The simulation results demonstrate that temperature-induced and salinity-induced turbulence have distinct influences on the scintillation index and consequently result in different system performances. In addition, the variation in the eddy diffusivity ratio in some intervals induces more complicated results for underwater optical communication. Moreover, the effect of the receiver aperture diameter on the aperture averaging factor is presented in anisotropic underwater turbulence. Such an effect is more obvious in the plane wave case than in the spherical wave case. These results can find potential application in the engineering design of optical communication systems in an underwater environment.
水下光通信一直是一项很有前景的技术，但由于折射率的波动导致的水下湍流，它受到了严重影响。在本文中，获得了一个修正的空间功率谱模型，该模型假设水下湍流是各向异性的，将折射率视为涡动扩散率的函数。基于该模型推导了在水下湍流中传播的平面波和球面波的闪烁指数。此后，考虑了光通信系统的性能，即中断概率和误码率，以及相关的孔径平均效应。仿真结果表明，温度诱导和盐度诱导的湍流对闪烁指数有不同的影响，从而导致不同的系统性能。此外，在某些区间内涡动扩散率的变化会给水下光通信带来更复杂的结果。而且，在各向异性水下湍流中给出了接收孔径直径对孔径平均因子的影响。这种影响在平面波情况下比在球面波情况下更明显。这些结果可在水下环境光通信系统的工程设计中找到潜在应用。
