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Theoretical Expression of the Aperture-averaged Irradiance Scintillation Index (ISI) for a Gaussian Beam in Non-Kolmogorov Turbulence with Finite Inner and Outer Scales
C. Gao and X-F. Li

This paper investigates the aperture-averaged irradiance scintillation index of a Gaussian beam propagating through a horizontal path in weak anisotropic turbulence. Analytical expressions are deduced based on the generalized exponential atmospheric spectrum for anisotropic turbulence, which includes the spectral power law value of non-Kolmogorov turbulence, the finite inner and outer scales of turbulence, the anisotropic factor, and other optical parameters of the Gaussian beam. The numerical results indicate that the aperture-averaged irradiance scintillation index (ISI) is more sensitive to the change of the inner scale than the outer scale, and an increasing aperture diameter or an increasing anisotropic factor can decrease the irradiance scintillation index at the receiver.

Keywords: Wireless laser communications, Gaussian beam, anisotropic non-Kolmogorov turbulence, inner and outer scales of turbulence, aperture-averaged effect, irradiance scintillation index (ISI)

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