Free-space optical communication link with shape-invariant orbital angular momentum Bessel beams

We present an alternative orbital angular momentum (OAM) solution for free-space optical communications in the form of shape-invariant Bessel beams. We use a generalized approach for generating these long-range self-healing beams with a phase-only element encoded on a spatial light modulator and imbue them with OAM. We study the performance of helical OAM beams as well as these long-range Bessel-like OAM beams over a real-world outdoor optical link of 150 m and show comparable performance. In the process, we characterize the link and its impact on modal cross-talk.