Multi-Stacked High-Speed PIN-PD for Compact Mobile Optical-Wireless Transceiver

We proposed a 0.3-mm large-aperture multi-stacked PIN-PD operated up to 20 Gbps to mitigate optical alignment tolerance in mobile optical wireless communications (OWCs). By reducing PIN junction capacitance using multi-stacked layers via fabrication, we achieved a 38-fold increase in 3 dB bandwidth (7.6 GHz) compared to a conventional 0.3-mm large PIN-PD. Assuming 10–20 km/h mobile communication applications at a short distance of 20 m, we developed a mobile OWC transceiver combined with a multi-stacked PIN-PD. In the mobile OWC demonstration considering a tracking latency of <5 ms against a moving beam (1.4 km/h) at 2.1 m, we successfully achieved bit error rate levels of 10
⁻⁶
at 10 Gbps and <3.8 × 10
⁻³
at 20 Gbps on a 2.1 m long optical bench (relative speed = 13.7 km/h at 20 m) for 1 hour.