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 similar to 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.

Automated summary

Anti-resonant hollow-core fibres offer lower nonlinearity and comparable characteristics to conventional fibres. We successfully demonstrated the delivery of 1 kW near-diffraction-limited continuous-wave laser light over a 1 km distance using a single-mode hollow-core fibre. This technology has potential applications in manufacturing, subsurface drilling, as well as sensing, particle acceleration, and gravitational wave detection.