362 Gbps from a chip smaller than 1mm². Cambridge just dropped a LiFi paper that's kind of insane

Researchers from the University of Cambridge, led by Professor Harald Haas—the inventor who coined the term "LiFi"—have published a breakthrough paper in Advanced Photonics Nexus. Their team created a chip-scale optical wireless communication system using a 5×5 array of 940nm Vertical-Cavity Surface-Emitting Lasers (VCSELs) on a die measuring just 845×810 micrometers, smaller than a fingernail. The system achieved an aggregate data rate of 362.71 Gbps across 21 functional lasers (with four lost during manufacturing), projecting to 431.8 Gbps if all 25 were operational. Each laser operates its own DCO-OFDM channel with adaptive bit loading up to 1024-QAM modulation, tested over a 2-meter free-space link.

The system's energy efficiency of approximately 1.4 nanojoules per bit is about half that of modern WiFi (802.11ax benchmarks around 2.6 nJ/bit). A custom micro-optics system shapes each laser beam into uniform square spots, creating a structured 5×5 illumination grid with over 90% spatial uniformity at 2 meters. This enables multiple independent channels that can serve different spatial zones simultaneously, meaning physical obstructions like a person walking through one beam don't collapse the entire connection. The research, funded by the UK government and published in a peer-reviewed SPIE journal, represents a lab demonstration with current receiver hardware bottlenecked at 1.4 GHz bandwidth—while the VCSELs themselves have 15 GHz intrinsic bandwidth, suggesting even higher future performance.