The effect of atmospheric turbulence on an optical wave can seriously degrade the reliability of an optical communication link. One atmospheric effect is scintillation, which is caused by index of refraction fluctuations. Several observations of atmospheric turbulence statistics suggest a modest change in the power law behavior of Kolmogorov' s power spectral density model. The corresponding index of refraction fluctuations are assumed to have spatial power spectra that obey power laws that deviate somewhat from the classical - 11/3 power law. The purpose of this study is to develop analytical models for scintillation and other wave propagation statistics based on non-classical power spectra. This involves random processes, asymptotic theory, and evaluating integrals involving special functions (Bessel functions and hypergeometric functions). Mean irradiance and scintillation index models are derived for a Gaussian-beam wave propagating through an atmosphere experiencing weak irradiance fluctuations. Also, the wave structure function for an unbounded plane wave and spherical wave is derived under weak turbulence theory. Using the derived plane wave structure function, the scintillation index for both a plane and spherical wave experiencing strong irradiance fluctuations is calculated. In addition, a scintillation model that is valid under all irradiance fluctuation conditions is derived for both a plane and spherical wave propagating through non-Kolmogorov atmospheric turbulence.

One of the negative effects that a laser beam experiences as it propagates through the atmosphere is intensity fluctuations or scintillation. Because scintillation-- as it pertains to laser radar and laser satellite communication systems-- is the main subject of this research, the assumption of an optical element ( such as a Gaussian lens) along the propagation path in front of the detector is valid. The mathematical addition of optical elements to the propagation path is treated using the ABCD ray matrix method. The expression for scintillation is derived, analyzed, and numerically calculated for positions to the left and right of the image plane, which is behind the collecting lens of a receiver system. Simultaneously, the behavior of the scintillation is investigated when the aperture size of the lens is increased. The results are compared to the aperture averaging effect experienced when the beam is in the image plane. This is a per-unit scintillation decrease because the aperture averages it over the surface of the lens.

Processing and analysis routines giving normalized moments of optical intensity, structure functions of wind velocity and temperature, central moments, and various measures of the turbulence parameter, C2N, are presented. Rapid analog-to-digital data conversion and storage to implement this analysis using MINC 11/23 with RT11 operating system are discussed. Coding for file organization and implementation of processing routines on the VAX 11/750, VMS operating system are also discussed.