Spatially partially coherent beam parameter optimization for free space optical communications

The problem of coherence length optimization in a spatially partially coherent beam for free space optical communication is investigated. The weak turbulence regime is considered. An expression for the scintillation index in a series form is derived and conditions for obtaining improvement in outage probability through optimization in the coherence length of the beam are described. A numerical test for confirming performance improvement due to coherence length optimization is proposed. The effects of different parameters, including the phase front radius of curvature, transmission distance, wavelength and beamwidth are studied. The results show that, for smaller distances and larger beamwidths, improvements in outage probability of several orders of magnitude can be achieved by using partially coherent beams.