Could a tiny chip help generate multiple stable millimetre-wave signals for future 6G and precision quantum timing? Researchers have demonstrated a new approach.
Researchers at Loughborough University and collaborating institutions have demonstrated a microcomb-based system that generated multiple precisely spaced millimetre-wave frequencies from a grain-of-rice-sized photonic chip. The work could support future high-capacity wireless links while also providing precisely controlled signals for timing, navigation, and quantum technologies.
At the centre of the system is a chip-based microresonator that produces a spectrum of precisely separated optical frequencies, known as a microcomb. Unlike conventional approaches that generate a single millimetre-wave frequency, the demonstrated system produced multiple frequencies simultaneously, creating several potential channels for high-frequency communications.
The researchers achieved this by combining the microresonator with a larger loop of optical fibre. Laser light circulated through both components, allowing the microcomb states to build up and remain stable. This configuration also allowed the researchers to control the relative strength of individual frequencies within the generated spectrum.
The resulting optical frequencies were converted into millimetre-wave signals using an antenna. Measurements showed that the precision and stability of the microcomb were retained in the generated millimetre waves, providing multiple highly controlled signals from the same system.
Millimetre waves offer greater bandwidth than lower-frequency wireless signals and are being investigated for future 6G networks, radar, spectroscopy, and astronomical instruments. The ability to generate several stable frequencies could allow multiple data channels to be produced from a compact photonic source.
The same frequency precision could also benefit quantum technologies, where accurate timing is important for synchronising systems. The team is testing the technology against precision clocks and exploring applications in timing, navigation, and positioning.
“The world is becoming increasingly data hungry. We want to send and receive more information, faster and in higher resolution, and millimetre waves could help provide the capacity to do that,” says Dr Luke Peters, of Loughborough University’s Emergent Photonics Research Centre.
