Authors

M. A. Al-Habash; L. C. Andrews;R. L. Phillips

Abbreviated Journal Title

Opt. Eng.

Keywords

lasers; propagation; irradiance; OPTICAL SCINTILLATIONS; ATMOSPHERIC-TURBULENCE; NUMERICAL-SIMULATION; FLUCTUATIONS; SPECTRUM; VARIANCE; STATISTICS; SCATTERING; RICIAN; Optics

Abstract

We develop a model for the probability density function (pdf) of the irradiance fluctuations of an optical wave propagating through a turbulent medium. The model is a two-parameter distribution that is based on a doubly stochastic theory of scintillation that assumes that small-scale irradiance fluctuations are modulated by large-scale irradiance fluctuations of the propagating wave, both governed by independent gamma distributions. The resulting irradiance pdf takes the form of a generalized K distribution that we term the gamma-gamma distribution. The two parameters of the gamma-gamma pdf are determined using a recently published theory of scintillation, using only values of the refractive-index structure parameter C-n(2) (or Rytov variance) and inner scale l(0) provided with the simulation data. This enables us to directly calculate various log-irradiance moments that are necessary in the scaled plots. We make a number of comparisons with published plane wave and spherical wave simulation data over a wide range of turbulence conditions (weak to strong) that includes inner scale effects. The gamma-gamma pdf is found to generally provide a good fit to the simulation data in nearly all cases tested.

Journal Title

Optical Engineering

Volume

40

Issue/Number

8

Publication Date

1-1-2001

Document Type

Article

Language

English

First Page

1554

Last Page

1562

WOS Identifier

WOS:000170933100020

ISSN

0091-3286

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