Erbium-ytterbium codoped thin-film lithium niobate integrated waveguide amplifier with 27 dB internal net gain

Photonic integrated waveguide amplifier fabricated on erbium-ytterbium (Er-Yb) co-doped thin-film lithium niobate (TFLN) has been investigated in this work. A small-signal internal net gain of 27 dB is achieved at the signal wavelength of 1532nm in the fabricated Er-Yb TFLN-waveguide amplifier pumped by the diode laser at ~980nm. Experimental characterizations reveal the advantage of waveguide fabrication by the photolithography assisted chemo-mechanical etching (PLACE) technique, and also the benefit from Yb-sensitized-Er in promoting the gain performance. The demonstrated high-gain chip-scale TFLN-amplifier is promising to be interfaced with established lithium niobate integrated devices, greatly extending the spectrum of TFLN photonic applications.