Yb-doped large-mode-area laser fiber fabricated by halide-gas-phase-doping technique

This is the authors' abstract. We don't add key points for this paper.

In this manuscript, we designed a rare-earth-halide gas-phase-doping setup to fabricate a large-mode-area fiber for high power laser applications. YbCl 3 and AlCl 3 halides are evaporated, carried respectively and finally mixed with usual host gas material SiCl 4 at the hot zone of MCVD system. Owing to the all-gas-phasing reaction process and environment, the home-made Yb-doped fiber preform has a homogeneous large core and modulated refractive index profile to keep high beam quality. The drawn fiber core has a small numerical aperture of 0.07 and high Yb concentration of 9500 ppm. By using a master oscillator power amplifier system, nearly kW-level (951 W) laser output power was obtained with a slope efficiency of 83.3% at 1063.8 nm, indicating the competition and potential of the halide-gas-phase-doping technique for high power laser fiber fabrication.