A high-gain cladded waveguide amplifier on erbium doped thin-film lithium niobate fabricated using photolithography assisted chemo-mechanical etching

Abstract Erbium doped integrated waveguide amplifier and laser prevail in power consumption, footprint, stability scalability over the counterparts bulk materials, underpinning lightwave communication large-scale sensing. Subject to highly confined mode micro-to-nanoscale moderate propagation loss, gain scaling such devices prove be more challenging compared their counterparts. In this work, a thin cladding layer of tantalum pentoxide (Ta 2 O 5 ) is employed erbium lithium niobate (LN) fabricated on film insulator (LNOI) wafer by photolithography assisted chemo-mechanical etching (PLACE) technique. Above 20 dB small signal internal net achieved at wavelength around 1532 nm 10 cm long LNOI pumped diode ∼980 nm. Experimental characterizations reveal advantage Ta higher optical with air-clad amplifier, which further explained theoretical modeling including guided structures steady-state response ions.