1.5-kW all-fiberized Yb-doped MOPA laser at 1105 nm with near-diffraction-limited beam quality and narrow spectral width

Abstract

We demonstrate an all-fiberized ytterbium-doped fiber laser (YDFL) at 1104.9 nm with a high optical signal-to-noise ratio (OSNR) by using ytterbium gain purely. The system is built based on FBG-based master oscillator power amplifier (MOPA) configuration, producing 1.5-kW power with a near-diffraction-limited beam quality (M2∼1.4) and a narrow spectral linewidth (FWHM∼70 GHz). The OSNR is ∼33 dB. A theoretical model is developed to calculate the amplified spontaneous emission (ASE) in the final amplifier. Both the calculated and experimental results suggest that the ASE or even parasitic lasing is the primary limitation for further power scaling. To the best of our knowledge, in >1100 nm wavelength range, this is the highest output power narrow spectral YDFL (with <100 GHz 3-dB spectral width) by using FBG-based MOPA configuration.