Mode Group Selection Method for Inter-mode Interference Suppression in OAM Multiplexing

This paper proposes a mode group selection method for orbital angular momentum (OAM) multiplexing to suppress inter-mode interference (IMI) owing to the misalignment of the beam axis. We have proposed an IMI suppression method employing even-numbered OAM modes, and its effectiveness has been successfully confirmed. Odd-numbered OAM modes are robust and used in addition to even-numbered modes to improve the robustness against the IMI, and the appropriate mode group is selected based on the system capacity. The effectiveness of the proposed method is demonstrated in terms of system capacity via computer simulations.