  We demonstrate high-power thin film lithium niobate (TFLN) erbium-doped
waveguide amplifier (EDWA) with a maximum on-chip output power of 113 mW and a
gain of 16 dB. The on-chip integrated EDWA is composed of large mode area (LMA)
waveguide structures with a total length of 7 cm and a footprint of 1x1 cm2.
Particularly, we connect segmented LMA waveguides with waveguide tapers to
achieve on-chip mode conversion which maintains single-mode propagation all
over the EDWA even at the waveguide bends. The design leads to significant
increase of the amplified signal power by orders of magnitude and will open an
avenue for applications such as on-chip high-power lasers and amplifiers
system.
