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Kilowatt-average-power single-mode laser light transmission over kilometre-scale hollow-core fibre


High-power laser delivery with near-diffraction-limited beam quality is typically limited to tens of metres distances by nonlinearity-induced spectral broadening inside the glass core of delivery fibres. Anti-resonant hollow-core fibres offer not only orders-of-magnitude lower nonlinearity but also loss and modal purity comparable to conventional beam-delivery fibres. Using a single-mode hollow-core nested anti-resonant nodeless fibre with 0.74 dB km−1 loss, we demonstrate the delivery of 1 kW of near-diffraction-limited continuous-wave laser light over a 1 km distance, with a total throughput efficiency of ~80%. From simulations, a further improvement in transmitted power or length of more than one order of magnitude should be possible in such air-filled fibres, and considerably more if the core is evacuated. This paves the way to multi-kilometre, kilowatt-scale power delivery that is potentially useful not only for future manufacturing and subsurface drilling but also for new scientific possibilities in sensing, particle acceleration and gravitational wave detection.

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Fig. 1: Characterization of the 1-km-long NANF.
Fig. 2: Demonstration of 1 kW power delivery over the 1 km NANF.
Fig. 3: Power-delivery performance of the 1 km NANF.
Fig. 4: Scalability of near-diffraction-limited CW power delivery in optical fibres at 1 µm, limited by SRS.

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Additional information on the numerical modelling method and code may be obtained from the corresponding authors upon reasonable request.


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We gratefully acknowledge support from the European Research Council (ERC) (grant agreement number 682724, ‘Lightpipe’), the UK Engineering and Physical Sciences Research Council (EPSRC) (programme grant EP/P030181/1, ‘Airguide Photonics’) and Saudi Aramco. The Royal Academy of Engineering is acknowledged for funding of Research Fellowships RF1516\15\46 (G.T.J.) and RF\201819\18\200 (E.N.F.). SPI is acknowledged for advice, useful discussions and for providing a laser source for initial tests. C. R. Smith and H. Kim are acknowledged for early contributions on the coupling of high-power laser beams into hollow-core fibres and for assistance with the splicing of NANF fibres, respectively. Y. Chen is acknowledged for advice and assistance with fibre fabrication.

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Authors and Affiliations



H.C.H.M., V.Z. and L.X. performed the power delivery, loss and M2 measurements. S.A.M. performed the simulations. H.S., T.D.B. and J.R.H. fabricated the fibres. G.T.J., E.N.F. and F.P. designed the fibres. A.T. produced the free-standing NANF coils. H.C.H.M., S.A.M., D.J.R. and F.P. wrote the manuscript. S.-U.A., D.J.R. and F.P. provided overall technical leadership across all aspects of the research.

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Correspondence to L. Xu or F. Poletti.

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Nature Photonics thanks Bill O’Neill and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Mulvad, H.C.H., Abokhamis Mousavi, S., Zuba, V. et al. Kilowatt-average-power single-mode laser light transmission over kilometre-scale hollow-core fibre. Nat. Photon. 16, 448–453 (2022).

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