On-Chip Integrated Waveguide Amplifiers on Erbium-Doped Thin-Film Lithium Niobate on Insulator

On‐chip light amplification with integrated optical waveguide fabricated on erbium‐doped thin‐film lithium niobate on insulator (TFLNOI) is demonstrated using the photolithography‐assisted chemomechanical etching (PLACE) technique. A maximum internal net gain of 18 dB is measured on a waveguide length of 3.6 cm, indicating a differential gain per unit length of 5 dB cm−1.