Efficient sorting for an orbital angular momentum multiplexing communication link based on a digital micromirror device and a diffuser

Efficient sorting multiple orbital angular momentum (OAM) spatial modes is a significant step in OAM multiplexing communications. Recently, wavefront shaping (WS) techniques have been implemented to manipulate light scattering through a diffuser. We reported a novel scheme for sorting multiplexed OAM modes faster and more accurately, using the complex amplitude WS based on a digital micromirror device (DMD) through a diffuser to shape the full field (phase and amplitude) of the OAM modes. In this study, we simulate this complex sorter for demultiplexing multiple modes and make a performance comparison with the previous sorter using the phase-only WS. Our results showed that for arbitrary two multiplexed modes, the sorter could achieve a high detection probability of more than 0.99. As the number of the multiplexed modes increases, the detection probability decreases to similar to 0.82 when sorting seven modes, which contrasts the similar to 0.71 of the phase-only sorters. We also experimentally verified the feasibility, that for arbitrary two modes, the sorter could reach a high detection probability of more than 0.99, and the complex sorter is capable of higher detection probability than the phase-only sorter under the same conditions. Hence, we anticipate that this sorter may potentially be demultiplexing multiple OAM spatial modes efficiently and quickly. (C) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement