1 May 2005 Analysis of laser multimode content on the angle-of-arrival fluctuations in free-space optics access systems
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Optical Engineering, 44(5), 056002 (2005). doi:10.1117/1.1905383
Abstract
The effects of laser beam multimode content on the angle-of-arrival fluctuations are examined for free-space optics (FSO) access systems. Multimode excitation is represented by coherent addition of Hermite-Gaussian modes. Mean square angle-of-arrival fluctuations are formulated using our previously reported multimode phase structure function. Numerical evaluations are obtained for practical FSO links operating at 1.55- and 0.85-µm wavelengths with link spans of up to 5 km. Mode content is arranged by sequentially grouping all possible mode combinations starting from the single fundamental mode (TEM00) up to a certain higher order (n,m). Angle-of-arrival fluctuations are found to be of the order of several tens of microradians, except for the cases when the mode group terminates with an odd mode or when the extremely higher order modes are present. In these instances, the fluctuations will rise to the radian level. From these results, it is concluded that the performance of a practical FSO receiver, having a field of view of several milliradians, will not be substantially affected by the angle-of-arrival fluctuations due to multimode excitation, provided that the mode content of source excitation is confined to mode indices below 20.
Halil Tanyer Eyyuboglu, Yahya Kemal Baykal, "Analysis of laser multimode content on the angle-of-arrival fluctuations in free-space optics access systems," Optical Engineering 44(5), 056002 (1 May 2005). http://dx.doi.org/10.1117/1.1905383
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KEYWORDS
Free space optics

Receivers

Turbulence

Optical engineering

Atmospheric propagation

Modes of laser operation

Spherical lenses

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