Tiny Light-Based Chips Could Make Your GPS Accurate to the Centimeter todayheadline

Imagine knowing your exact location down to the centimeter, or having time measurements so precise they could detect subtle changes in the Earth’s surface. A breakthrough in miniaturizing optical atomic clocks brings this future closer to reality, with potential implications for everything from self-driving cars to volcano monitoring.

Scientists from Purdue University and Chalmers University of Technology have developed a chip-based technology that could help shrink ultra-precise optical atomic clocks from laboratory-sized setups to components small enough to fit in everyday devices.

From Meters to Centimeters

“Today’s atomic clocks enable GPS systems with a positional accuracy of a few meters,” explains Professor Minghao Qi from Purdue University. “With an optical atomic clock, you may achieve a precision of just a few centimeters. This improves the autonomy of vehicles, and all electronic systems based on positioning.”

The researchers’ innovation centers on devices called microcombs – tiny chips that generate evenly spaced frequencies of light, similar to the teeth of a comb. These chips serve as a crucial bridge between the ultra-high frequencies used in optical atomic clocks and the electronic signals needed to count time.

Solving the Miniaturization Challenge

While current atomic clocks power our GPS systems and digital devices, they typically use microwave frequencies. Newer optical atomic clocks offer far greater precision but have remained confined to laboratories due to their size and complexity.

The research team overcame this limitation through an innovative pairing of microcombs. “We managed to solve the problem by pairing two microcombs, whose comb spacings are close but with a small offset,” says Kaiyi Wu, the study’s lead author at Purdue University. This configuration allows the system to convert precise optical signals into more manageable electronic frequencies.

Beyond Navigation

The implications extend far beyond just more accurate GPS. Professor Qi notes that an optical atomic clock “can detect minimal changes in latitude on the Earth’s surface and can be used for monitoring, for example, volcanic activity.”

The technology integrates photonic components – including frequency combs, atomic sources, and lasers – onto chips measuring just micrometers to millimeters in size. The team’s photonic chip, containing 40 microcomb generators, is merely five millimeters wide.

From Lab to Everyday Life

“Photonic integration technology makes it possible to integrate the optical components of optical atomic clocks… on tiny photonic chips in micrometer to millimeter sizes, significantly reducing the size and weight of the system,” Wu explains.

Victor Torres Company, Professor of Photonics at Chalmers and study co-author, sees broader implications: “We hope that future advances in materials and manufacturing techniques can further streamline the technology, bringing us closer to a world where ultra-precise timekeeping is a standard feature in our mobile phones and computers.”

The Road Ahead

While this research represents a significant step forward, work remains to create a complete system-on-chip. The technology could eventually enable optical atomic clocks in satellites, remote research stations, and drones – applications currently impossible with traditional laboratory-sized systems.

The research, titled “Vernier microcombs for integrated optical atomic clocks,” was published in Nature Photonics. It represents a collaboration between researchers at Purdue University, Chalmers University of Technology, and King Saud University.