Probability density function of fiber-coupling efficiency and temporal power spectrum of irradiance fluctuations in the anisotropic non-Kolmogorov satellite-to-ground downlink

Abstract

As many related experimental and theoretical results are identified, scholars have found that the anisotropy of turbulence cells is indispensable in the atmospheric turbulence. In this paper, based on a new anisotropic non-Kolmogorov turbulence spectrum for the satellite links that is applicable to both vertical and slant links, the probability density function of fiber-coupling efficiency and the temporal power spectrum of irradiance fluctuations for a plane wave propagating through the weak anisotropic non-Kolmogorov satellite-to-ground downlink are developed. The results show that when the zenith angle is greater than a certain angle, the probability density function of fiber-coupling efficiency shifts to the side with smaller coupling efficiency with the rising of anisotropic factor, and the temporal power spectrum of irradiance fluctuations and the absolute value of power exponent at high frequencies increase with the growing of anisotropic factor and power law, but while the zenith angle is less than the certain angle, the opposite trend will appear. It is anticipated that this work will benefit the understanding of laser beam transmission in anisotropic non-Kolmogorov satellite links and provide the theoretical basis for the design and parameter optimization of satellite optical communication systems based on fiber-coupling.