Multi-vortex laser enabling spatial and temporal encoding

Optical vortex is a promising candidate for capacity scaling in next-generation optical communications. The generation of multi-vortex beams is of great importance for vortex-based optical communications. Traditional approaches for generating multi-vortex beams are passive, unscalable and cumbersome. Here, we propose and demonstrate a multi-vortex laser, an active approach for creating multi-vortex beams directly at the source. By printing a specially-designed concentric-rings pattern on the cavity mirror, multi-vortex beams are generated directly from the laser. Spatially, the generated multi-vortex beams are decomposable and coaxial. Temporally, the multi-vortex beams can be simultaneously self-mode-locked, and each vortex component carries pulses with GHz-level repetition rate. Utilizing these distinct spatial-temporal characteristics, we demonstrate that the multi-vortex laser can be spatially and temporally encoded for data transmission, showing the potential of the developed multi-vortex laser in optical communications. The demonstrations may open up new perspectives for diverse applications enabled by the multi-vortex laser.