Hollow-Core Photonic Fiber Technologies

Hollow-core photonic fibres guide light predominantly through an air-filled central channel rather than solid glass, drastically reducing material absorption and nonlinear effects. Two principal guiding mechanisms have emerged: photonic bandgap (PBG) and antiresonant reflecting optical waveguide (ARROW) designs. PBG fibres rely on a periodic cladding structure that forbids certain wavelengths from escaping the core, whereas ARROW or negative-curvature designs exploit thin capillary walls to reflect light back into the hollow core across broad spectral windows. Recent innovations focus on minimising transmission loss through advanced microfabrication to control core boundary curvature, surface roughness and cladding geometry. The capacity to fill these fibres with gases has unlocked new regimes of mid-infrared and far-infrared laser generation, high-power delivery and precise sensing. Globally, such fibres are revolutionising telecommunications by alleviating nonlinear limitations, enabling high-power beam delivery for machining and defence, and enhancing spectroscopic sensitivity for environmental monitoring and biomedical diagnostics.

Research from Nature Portfolio

Recent studies have achieved ultralow losses in the visible and ultraviolet by smoothing the hollow-core surface to sub-nanometre roughness, yielding record attenuation reductions and opening access to short-wavelength guidance with losses orders of magnitude below conventional solid-core fibres. Foundations in negative-curvature conjoined-tube designs have demonstrated broad bandwidth spanning major telecommunications bands with transmission losses as low as a few decibels per kilometre. These advances underpin next-generation high-capacity networks by combining low latency, minimal dispersion and high damage thresholds.

Hollow-Core Photonic Fiber Technologies publication trend

The graph below shows the total number of articles in hollow-core photonic fiber technologies across all publications each year (not limited to Nature Index journals).

Technical terms

Photonic bandgap guiding: A mechanism using a periodic cladding to create forbidden wavelength ranges that confine light to the hollow core.

Antiresonant guiding: A design in which thin cladding elements reflect out-of-band light back into the core to achieve broad low-loss transmission.

Negative curvature: A core boundary shape with inwardly curved walls that reduces optical overlap with glass, minimising scattering and confinement loss.

Epsilon-near-zero (ENZ) material: A medium whose permittivity approaches zero at certain wavelengths, enabling novel light confinement by altering boundary reflection.

References

1. 4.8-μm CO-filled hollow-core silica fiber light source. Light: Science & Applications (2024).
2. Hollow-core fibers with reduced surface roughness and ultralow loss in the short-wavelength range. Nature Communications (2023).
3. 2.2 kW single-mode narrow-linewidth laser delivery through a hollow-core fiber. Optica (2023).
4. Hollow core optical fiber enabled by epsilon-near-zero material. Nanophotonics (2024).
5. Hollow-core conjoined-tube negative-curvature fibre with ultralow loss. Nature Communications (2018).