27 May 1998 Adaptive beam-size control for ground-to-satellite laser communications
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Atmospheric turbulence severely degrades the performance of uplinks. Employment of adaptive optics to enhance ground-space laser communication systems has recently been considered and possible benefits have been shown. Uplink scintillation reduction by using multiple transmitters is also being considered. What appears to be currently missing in these works is the realization that transmitter beam-size is a crucial design parameter and its optimum value changes continuously according to changing turbulence conditions along the propagation path. In this paper we consider a configuration where uplink transmitter beam-size is controlled in real-time in response to measured turbulence parameters to maximize mean intensity and minimize fluctuations on the satellite receiver. Controlling the beam-size, especially by a factor of two or so, in relatively long time scales (seconds) should not be a problem. Although it is obvious that this will greatly improve the performance of especially a variable data rate communication system, we find that the current state of knowledge is fragmentary and insufficient to quantify the improvement in any general and sufficiently accurate way. Semi-analytic simulations can be useful in exploring the improvement for different scenarios and site conditions
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Yusuf E. Yenice, Yusuf E. Yenice, Barry G. Evans, Barry G. Evans, } "Adaptive beam-size control for ground-to-satellite laser communications", Proc. SPIE 3266, Free-Space Laser Communication Technologies X, (27 May 1998); doi: 10.1117/12.308710; https://doi.org/10.1117/12.308710

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