The use of multiple, mutually incoherent beams for a laser link through turbulence can reduce the effects of scintillation
at the receiver. A recent approach involving an array of parallel propagating beams in a circle pattern has been presented
in the literature and studied to determine the best beam spacing for the lowest scintillation effects. This approach has the
disadvantage of reduced irradiance at the receiver as the beam separation increases. To remove this constraint, we
present a modified approach where the multiple beams are individually aimed at the receiver. A wave (physical) optics
simulation was applied to study the performances of 2-, 3-, 4-, and 5-beam transmitter sources. The mean irradiances <i>I</i>
and scintillation indices σ<sub>I</sub><sup>2</sup> are examined for some specific link geometries and fluctuation strengths and the results are
compared with those of the original method. For evaluation, we also employ a recently proposed performance metric
that incorporates both <i>I</i> and σ<sub>I</sub><sup>2</sup> to indicate the near-optimal beam separation for the cases studied. Finally, we examine
the probability of fade for our selected cases the modified approach has improved performance.
A fiber bundle arrangement has been proposed in the literature to produce a partially spatially coherent beam. The
bundle contains fibers of random lengths and the source has limited temporal coherence. The analytical expression for
the autocorrelation function of the bundle pupil is derived, which defines the behavior of the beam as it propagates.
Simulation results are used to verify the analytic theory. The far-field irradiance pattern for the bundle arrangement is
addressed analytically and through wave optics simulation. Averaging the irradiance pattern for a number of simulation
realizations was shown to converge to the analytic result. The process of averaging over a small band of source
wavelengths is developed and is shown to result in a spatially partially coherent beam. Simulation results again
compared favorably with the analytic theory.