Angle-sensor-assisted auto-coupling system for high-speed wide-field optical wireless communication

Infrared optical wireless communication (OWC) is a promising candidate for next-generation wireless links due to its high bandwidth and inherent security. However, the limited field-of-view (FOV) of terminals induces great difficulty in establishing line-of-sight (LoS) link between the transmitter and the terminal. In this paper, to facilitate efficient beam alignment, we report an auxiliary strategy integrating an external angle-sensing module with a wide-FOV telecentric receiver architecture, providing the receiver with real-time incident of angle (IoA) information to transform the traditional blind search into a deterministic alignment process. Three different angle-sensing modalities-monocular vision, binocular stereo vision, and LiDAR scanning-are systematically evaluated. Experimental results indicate that the precision of vision-based methods degrades significantly when the detection distance exceeds 1.3 m, whereas the LiDAR-based scheme maintains an angular error below 0.714° across a 3 m range and a 100° FOV, demonstrating superior robustness and reliability. By leveraging the LiDAR-derived IoA, the receiver implements a "coarse-to-fine" two-stage alignment mechanism. Combined with a non-coaxial correction algorithm, this approach bypasses the need for redundant internal search modules and bulky fiber bundles, enabling a single fiber to achieve micron-level auto-coupling with a peak steady-state efficiency of 54.2%. Under these conditions, a 10 Gbps on-off-keying (OOK)-modulated OWC link is successfully maintained within a 100° FOV, with the bit error rate (BER) consistently meeting the forward error correction (FEC) requirement. This research demonstrates that sensor-aided alignment simplifies terminal architecture and accelerates link acquisition, providing a viable pathway for wide-FOV optical wireless networks.