We demonstrate an erbium-doped waveguide amplifier by erbium ion implantation in Si3N4 photonic integrated circuits, achieving 145 mW on-chip output power and more than 30 dB small-signal gain, which is on par with commercial fiber amplifiers and beyond state-of-the-art III-V heterogeneously integrated semiconductor amplifiers. (C) 2022 The Author(s)