| Free space optical (FSO) communication systems are attractive for the military because these systems are capable of transmitting extremely high data rates over very long point-to-point links. However, in the presence of atmospheric turbulence the FSO channel will be distorted and limits the effective data rate that can be transmitted over the link. These distortions can affect the signal in the spatial, time and frequency (wavelength) domains. It is well known that channel coding and diversity techniques can be employed to mitigate the channel distortions and improve the performance of the communications link. In order for these techniques to be employed the FSO channel properties have to be charactertized. In this paper we will examine the
correlation of the FSO channel across wavelengths under weakly turbulent channel distortions. Specifically, we will determine the correlation coefficient of the channel in the far-field and the near-field. The former case is appropriate in
ground-to-satellite links and the latter for short-haul air-to-air links. (This paper to be submitted to session 09H1.)
|