Impact of Crosstalk on Mode-division Multiplexing (MDM)-based Multi-beamforming System

Multi-beamforming is the key technology to improve radar coverage. The combination of the mode-division multiplexing (MDM) technology and the multi-beamforming could achieve a breakthrough in the number of beams compared to the traditional multi-beamforming system, and provide a feasible solution for the future large-scale multi-beamforming system. However, the inherent crosstalk from MDM devices would affect the amplitude of the beam and lead to the deterioration of the beam quality, severely limiting the performance of the system. In this paper, we propose the novel MDM-based multi-beamforming scheme through using four optical modes, i.e.,
$\text{LP}_{01},\ \text{LP}_{11a},\ \text{LP }_{11b}\ \text{and}\ \text{LP}_{02}$
, to form four beams pointing at different angles. By considering the mode-induced crosstalk caused by MDM devices, we evaluated the beam quality and explored the impact of crosstalk on the beam quality. Sweeping the crosstalk intensity of the key element in the MDM-based multi-beamforming system, i.e., the photon lantern, we recorded the various quality parameters of the formed beam. Explored the impact of mode crosstalk on multi-beamforming system performance from multiple perspectives.