OTenna: a reconfigurable free-space optical fabric for chip-to-chip interconnects

AI computing systems, warehouse robots, and autonomous drones all require unprecedented data movement bandwidth, low latency, and reconfigurable connectivity. Copper interconnects, mmWave radios, and fiber-based optical networks face fundamental scaling limits in bandwidth density, power efficiency, and topology rigidity. OTenna is a CMOS-compatible free-space optical phased array (OPA) technology that forms electronically steerable light beams for terabit-class point-to-point links without fibers or mechanical beam steering. Using leaky-wave silicon photonics with liquid-crystal phase tuning, OTenna supports 2D beam steering, multi-beam parallelism, and reconfigurable topologies. We present OTenna as a unifying optical fabric for two high-impact applications: (1) chip-to-chip communication in AI server packages, enabling > 50 Tb/s per package with sub-pJ/ bit energy efficiency, and (2) machine-to-machine (M2M) networking among autonomous robots and drones, enabling secure, interference-free, and scalable optical meshes. This paper describes the device architecture, free-space link design, system integration, and application-level benefits for both domains.