Polarization Insensitive Real-Time OWC Enabled by Multi-Mode-Based Beam Shaping via Offset Launch

Optical wireless communication (OWC) utilizing unregulated broadband optical spectrum is regarded as a powerful candidate to meet the requirement for high-speed wireless connectivity. Here we propose a polarization insensitive OWC scheme by using multi-mode based beam shaping (MM-BS) technique via offset launch in a multi-mode fiber (MMF). With the proposed configuration and coherent dual polarization QPSK (DP-QPSK) modulation, a real-time 10 Gb/s optical wireless link over 4.2 m free-space is experimentally demonstrated for multi-user scenario, achieving −38.8 dBm receiver sensitivity and >12cm coverage range. Moreover, a 20 Gb/s PAM4 OWC link over 1.2 m free-space is performed with −22.2 dBm receiver sensitivity and >3.2 cm coverage range. The measured results reveal the feasibility of the proposed scheme to build a high-speed high-performance wireless connectivity.