Joint signal current probability distribution for optical heterodyne receiver arrays in the turbulent atmosphere.

Optical heterodyne receiver arrays operating in the presence of atmospheric turbulence are considered. Approximate expressions are presented for the joint probability density functions of the intermediate frequency signal magnitude vectors from optical heterodyne receiver arrays operating in the presence of clear air turbulence. The analysis considers the effects of arbitrarily correlated amplitude fluctuations and arbitrarily correlated phase front perturbations in the presence of local oscillator shot noise. Both passive receiver arrays and those employing active tilt tracking systems to eliminate angle-of-arrival fluctuations are described. The special case of a two-detector, nontracking array is discussed in detail, both theoretically and experimentally.