Performance evaluation of an adaptive optics, free-space laser communications system from simulation of beam propagation

摘要

Free-space optical communications have distinct advantages over conventional RF and microwave systems by virtue of their high carrier frequencies that permit high modulation bandwidth, enhanced security, freedom from interference, and low powered. However, the turbulent atmosphere causes phase variations along the path that are manifested in intensity variations (scintillation) and high beam divergence. These variations are a noise source that reduces the ability of the receiver to determine the information contained in the modulation. For many years, the emphasis throughout this area has been on elucidating those implications of the atmospheric propagation problem that bear on the design and performance of optical communication systems. In this work, it is our intention to elucidate how the addition of adaptive optics to the transmitter or receiver can reduce the effects of atmospheric propagation and, in so doing, to quantify the improvement on the performance of optical communications systems regarding incoherent detection. Adaptive optics offers the potential for overcoming these limitations by adaptive tracking of the beam and correction of atmospherically-induced aberrations.