Researchers from Poland and China have developed a method for printing microscopic structures directly onto the end of optical fibres to generate so-called vortex beams, a technology seen as a potential route toward higher-capacity optical communication systems.
The study, published in the journal Optical Fiber Technology, addresses growing demand for faster and more efficient data transmission driven by expanding internet traffic, artificial intelligence systems and large-scale data centres.
Scientists say vortex beams, also known as beams carrying orbital angular momentum, could allow multiple streams of information to travel simultaneously through a single optical fibre by encoding data in the geometry of light itself.
In conventional fibre-optic systems, increasing transmission capacity usually requires additional wavelengths, new transmission paths or more complex electronics. Vortex beams add another layer of information encoding by exploiting the helical structure of the light wave.
According to the researchers, different orbital angular momentum modes remain distinguishable during propagation, allowing them to function as separate communication channels within the same beam.
The work was carried out by researchers from the Warsaw University of Technology in collaboration with Chinese scientists. The team fabricated microscopic spiral structures directly on fibre ends using two-photon polymerisation, a high-precision micro- and nanoscale 3D-printing technique.
The printed structures convert ordinary laser light into vortex beams without requiring large external optical components.
Researchers tested two design variants — stepped and smooth spiral structures — and found that smooth geometries produced better results, including lower signal loss and more efficient conversion of light into the desired vortex mode.
The study highlights a broader trend in photonics toward manufacturing methods that tailor optical components directly to the physical behaviour of light, rather than relying on conventional machining constraints.
The experiments focused on light at wavelengths around 2 micrometres, a spectral region attracting increasing interest for applications in optical communications, lidar systems and advanced photonic technologies.
Researchers also demonstrated through simulations and partial experimental verification that the same approach could function at wavelengths commonly used in existing telecommunications infrastructure, including 980, 1310 and 1550 nanometres.
Scientists say the findings increase the prospects for integrating vortex-beam technology into future communication systems, imaging technologies and quantum devices.
The researchers note that traditional optical components used to generate vortex beams are often relatively large and require extremely precise alignment, limiting their integration into compact photonic systems. By contrast, structures fabricated directly on optical fibres could simplify deployment and miniaturisation.
The project was co-financed by the Polish National Science Centre under the Polish-Chinese SHENG 3 programme. (PAP)
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