New research in structured light means researchers can exploit the many patterns of light as an encoding alphabet without worrying about how noisy the channel is

A breakthrough in optical communication as the Wits research team unveils their ‘vectorness’ protocol – a revolutionary approach to noise-free structured light communications.

Researchers at the University of the Witwatersrand (Wits) have introduced a groundbreaking optical communication protocol that harnesses the potential of spatial light patterns for multi-dimensional encoding without the need for pattern recognition.

This development addresses the long-standing challenge of distortion in optical communications caused by atmospheric turbulence or bent optical fibers. By leveraging a new property of vectorial light called “vectorness,” which remains unchanged when transmitted through noisy channels, the Wits team from the Structured Light Laboratory in the Wits School of Physics achieved a state-of-the-art encoding method.

They successfully transmitted over 50 vectorial light patterns virtually free from noise across turbulent atmospheres, presenting a novel approach to high-speed optical communication.

Published recently in Laser & Photonics Reviews, the study showcases how the team utilized the invariant nature of vectorness to encode information. The concept of “vectorness” is quantified on a scale of 0 to 1, retaining its value regardless of the presence of noise.

Unlike traditional amplitude modulation, which represents a binary alphabet (0 or 1), the team exploited the invariance of vectorness to divide the range between 0 and 1 into more than 50 segments (such as 0, 0.02, 0.04, etc.), resulting in a 50-letter alphabet.

Since the vectorness remains unaltered during transmission, both the sender and receiver consistently agree on its value, ensuring noise-free information transfer.

The team’s remarkable achievement lies in its ability to employ light patterns in a manner that does not necessitate pattern recognition, thereby disregarding the inherent distortion in noisy channels. Instead, by summing up light through specialized measurements, they revealed a quantity that remains unaffected by the distortion it encounters.

“This is a very exciting advance because we can finally exploit the many patterns of light as an encoding alphabet without worrying about how noisy the channel is,” adds Professor Andrew Forbes, from the Wits School of Physics. “In fact, the only limit to how big the alphabet can be is how good the detectors are and not at all influenced by the noise of the channel.”

Lead author and Ph.D. candidate Keshaan Singh says: “To create and detect the vectorness modulation requires nothing more than conventional communications technology, allowing our modal (pattern) based protocol to be deployed immediately in real-world settings.”

The team has already begun testing in optical fiber and fast links across free space, and they believe the approach will work in other noisy channels, including underwater.

Image Credit: Wits University