High-gain optical parametric amplification with continuous-wave pump using domain-engineered thin film lithium niobate waveguide

While thin-film lithium niobate (TFLN) is known for efficient signal generation, on-chip signal amplification remains challenging from fully integrated optical communication circuits. Here we demonstrate the continuous-wave-pump optical parametric amplification (OPA) using an x-cut domain-engineered TFLN waveguide, with high gain over the telecom band up to 13.9 dB, and test it for high signal-to-noise ratio signal amplification using a commercial optical communication module pair. Fabricated in wafer scale using a process that is common for devices including modulators, this OPA device marks an important step in TFLN photonic integration.