Abstract
Hollow-core anti-resonant fibers (HC-ARFs) provide an attractive platform for high-power laser delivery because most of the optical field propagates in air, enabling high damage thresholds, weak light-silica interaction, and low optical nonlinearity. Here, we demonstrate all-fiber delivery of 1338 W continuous-wave laser power through a 2-m HC-ARF with a 14-µm mode-field diameter and a coupling efficiency of 97.1%. Efficient coupling is achieved by fusion splicing a mode-matched solid-core delivery fiber to the HC-ARF with an anti-reflection-coated end face and optimized offset-arc parameters. The fiber shows negligible bend-induced loss for bend diameters down to 13 cm, supporting compact and flexible deployment. Furthermore, the system enables passive beam cleaning, improving the beam quality factor (M
2
) from 1.25 to 1.15 via the preferential attenuation of higher-order modes. This compact all-fiber HC-ARF system combines a small mode field, kilowatt-level power density, and near-diffraction-limited beam quality, offering stable and flexible delivery of high-quality beams.