Large-Angle-Coverage 2D Optical Wireless Communications via Optical Phased Arrays

Abstract

Two dimensional (2D) optical wireless communications (OWC) with a large-angle coverage are eagerly being pursued by wireless and mobile applications of Internet of Things, high-resolution image/video transmission, 6G/beyond wireless communications and network, remote conference and diagnosing, etc. Silicon photonics based optical phased array (OPA) can provide the large-angle beam scanning for OWC, benefitting from the near-half-wavelength OPA antenna spacing. However, the coupling loss of the laser source to the OPA chip is too high, meanwhile the sensitivity for state-of-the-art OWC receiver is too poor to meet the practical requirements for OPA-based OWC. The additional optical amplification is inevitably required to enhance the transmitted power and the received power of the OWC system. In this work, we present the large beam-scanning angle of OPA by simultaneously phase-controlling multi-wavelength beams. A compact wavelength-division-multiplexing (WDM) emitter provides an efficient and broadband source of 1270 nm-1610 nm to trigger parallel emissions off the OPA grating antennas, covering the whole optical communication band. Furthermore, we enhance the sensitivity to −40 dBm for OWC using a highly sensitive avalanche photodiode without additional optical amplification. Finally, the 2D OPA-based OWC with the coverage angle of 48° × 50° is achieved by actively controllable phase tuning of WDM-radiated 18 beams.