Free-Space Terabit Optical Interconnects
Marco A. Fernandes, Paulo P. Monteiro, Fernando P. Guiomar
Abstract
The continuous growth of Internet data traffic is progressively increasing the pressure over wireless access technologies. To overcome the imminent bandwidth bottleneck, free-space optics (FSO) is currently deemed as a key breakthrough towards next-generation ultra-high-capacity wireless links. As this technology matures, it is starting to find its place not only in future mobile access networks, but also in applications such as datacenter interconnections, satellite communications and high-frequency trading. To meet the ever-increasing demand for high-capacity links, future-proof FSO systems should seek maximum compatibility with state-of-the-art optical fiber systems, which nowadays can already provide data rates per channel in the Terabit/s range. However, the ultra-wideband potential of FSO systems comes at the expense of very tight requirements in terms of optical beam alignment, so that reliable end-to-end communications can be ensured. Following this research challenge, in this work we demonstrate a dynamic single-wavelength 1 Tbps FSO link with high pointing error tolerance, boosted by adaptive probabilistic constellation shaping (PCS) and an active gimbal-based acquisition, tracking and pointing (ATP) mechanism. Our results demonstrate successful indoor FSO transmission over 3 m with enhanced resilience towards pointing errors, enabling to adapt the data rate in the range of 0.8–1 Tbps.