High-Performance and High-Capacity Ultraviolet Communication With Orbital Angular Momentum

In this paper, a high-performance and high-capacity ultraviolet (UV) communication system is presented using orbital angular momentum (OAM) of the Laguerre-Gaussian beam. It is well known that the Laguerre-Gaussian beams propagating along the same axis with different azimuthal states are mutually orthogonal. This orthogonality property allows OAM beams to be potentially useful in improving the performance of a UV communication system. In addition, an OAM beam with fixed angular momentum value could act as a data channel. We first derive a novel analytical expression for the UV channel impulse response considering the Laguerre-Gaussian beam with a fixed OAM mode value acting as a data channel. Based on this impulse response, novel expressions for average symbol error rate (ASER) and channel capacity are derived. It is shown via simulation that the proposed OAM based UV communication system achieves significantly higher error performance and higher channel capacity than conventional UV systems. It is also found that the received beam divergence is the main factor limiting the performance of the proposed system.