Anisotropic atmospheric turbulence and partially coherent self-focusing vortex beams for wireless optical communication

It is generally believed that employing partially coherent light for wireless optical communication can improve the communication performance. In this paper, we show that whether the partial coherence contributes positively or negatively depends on the turbulence strength of the link. For illustration, partially coherent self-focusing vortex (PCSFV) beams propagating via anisotropic atmospheric turbulence at different altitudes are investigated. It is shown that lower coherence improves focusing and helps the signal receiving only for low-altitude and strong turbulence. There is an altitude related to the critical turbulence strength of the turbulence at which the communication performance is almost independent of the initial coherence of the beam. Besides, we focus on the channel capacity as well as the bit error rate (BER) for a high-altitude link. The results show that stronger anisotropy and larger inner scale parameters lead to higher average channel capacity with lower BER. By adjusting the beam waist or receiving aperture size, the communication performance can be further maximized. Our study represents the pioneering effort to assess the different impacts of the initial partial coherence on the receiving probability and validate the potential applications of PCSFV beams in wireless optical communications.