University of Cambridge researchers demonstrated a chip-scale optical wireless system capable of delivering aggregate data rates of more than 360 Gb/s while using significantly less energy per bit than conventional Wi-Fi.

The work, published in Advanced Photonics Nexus, combines a 5×5 array of vertical-cavity surface-emitting lasers (VCSELs) with custom beam-shaping optics to create a compact platform for high-speed indoor wireless links.

Optical wireless communication, which transmits data using light rather than radio frequencies, has long been positioned as a complement to Wi-Fi and cellular systems. It offers access to a much wider spectrum and avoids radio interference, but has historically struggled to combine high throughput, energy efficiency, and scalable deployment in a single system.

The Cambridge team’s approach focuses on parallelization at the transmitter. Each of the 25 lasers in the array can be individually addressed, allowing multiple data streams to be transmitted simultaneously. In testing, 21 of the lasers were operational, with individual channels delivering between 13 Gb/s and 19 Gb/s. Combined, the system reached an aggregate throughput of 362.7 Gb/s over a two-meter free-space link.

The system uses orthogonal frequency-division multiplexing (OFDM) to maximize spectral efficiency, a technique widely used in radio-based systems but adapted here for optical transmission.

One of the challenges in scaling optical wireless systems is managing interference between beams. If multiple light sources overlap, receivers can struggle to distinguish between signals. To address this, the researchers developed a compact optical assembly that shapes and steers the emitted light into a structured grid of square illumination zones.

At two meters, the system achieved more than 90% uniformity across the illuminated area, allowing different beams to be assigned to different users or devices. In a multi-user test with four active beams, the system maintained stable links and delivered a combined data rate of around 22 Gb/s.

Energy efficiency is another key focus. The researchers report an energy consumption of approximately 1.4 nanojoules per bit (nJ/bit), roughly half that of state-of-the-art Wi-Fi under comparable conditions. The use of VCSELs, which can be directly modulated at high speed with relatively low power, is central to that improvement.

However, the current setup remains constrained by the receiver. The experiments used a commercial photodetector with limited bandwidth, meaning higher data rates should be possible with more advanced components. In other words, the headline number reflects a best-case setup rather than a deployable system.

The system also remains a laboratory demonstration. The demonstration relies on a controlled two-meter link and carefully aligned optics, highlighting the gap between proof-of-concept performance and real-world deployment in dynamic indoor environments.

Even so, the work indicates a path forward for optical wireless systems that can offload traffic from congested radio networks in high-density settings such as offices, data centers, and public venues.

Rather than replacing Wi-Fi, the researchers position optical links as a complementary layer, providing high-capacity, energy-efficient connectivity where demand is concentrated.