Instead of a traditional solid glass core, the newly-developed optical fibers feature a core of air surrounded by a meticulously engineered glass microstructure to guide light. This design increases transmission speeds by 45% and allows more data to be transmitted over further distances before it requires boosting.
Petrovich et al. report a microstructured optical waveguide with unprecedented transmission bandwidth and attenuation. Image credit: Gemini AI.
Optical fibers used for telecommunications typically feature a solid silica glass design, and despite decades of optimization, their signal loss has been a limiting factor.
As such, about half of the light transmitted through the fiber is lost after about 20 km, requiring the regular use of optical amplifiers to boost signals for longer distance transmission, such as intercontinental terrestrial or subsea links.
Lowering the level of signal loss can be achieved over a small wavelength range, which limits the amount of data that can be transmitted, which has restricted optical communications over the past several decades.
University of Southampton researcher Francesco Poletti and his colleagues made new optical fibers with a hollow air core surrounded by a fine pattern of thin silica rings to guide the light.
When testing the fibers in laboratory experiments, the authors found that the fiber featured an optical loss of only 0.091 decibels per km at a light wavelength commonly used in optical communications.
As a result, light signals with suitable wavelengths could travel around 50% further before they required boosting.
This design also provides a much broader transmission window (range of wavelengths where light can travel with minimal signal loss and distortion) compared to previous optical fiber designs.
This new type of optical fiber could potentially feature even lower losses by using a larger air core, though further research is needed to confirm this.
“We are confident that, with advancements in produced volumes, geometrical consistency and reduced presence of absorbing gases in the core, the new fibers will establish themselves as a pivotal waveguiding technology,” the reserchers said.
“This innovation has the potential to enable the next technological leap in data communications.”
Their paper appears in the journal Nature Photonics.
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M. Petrovich et al. Broadband optical fibre with an attenuation lower than 0.1 decibel per kilometre. Nat. Photon, published online September 1, 2025; doi: 10.1038/s41566-025-01747-5
