Optical amplifiers are fundamental to modern photonics, enabling long-distance communications1, precision sensing2,3 and quantum information processing4,5. Erbium-doped amplifiers dominate telecommunications but are restricted to specific wavelength bands1,6, whereas semiconductor amplifiers offer broader coverage but suffer from high noise and nonlinear distortions7. Optical parametric amplifiers (OPAs) promise broadband, quantum-limited amplification across arbitrary wavelengths8. However, their miniaturization and deployment have been hampered by watt-level power requirements. Here we demonstrate an integrated OPA on thin-film lithium niobate that achieves >17 dB gain with <200 mW input power—an order of magnitude improvement over previous demonstrations. Our second-harmonic-resonant design enhances both pump generation efficiency (95% conversion) and pump power utilization through recirculation, without sacrificing bandwidth. The resonant architecture increases the effective pump power by nearly an order of magnitude compared with conventional single-pass designs, while also multiplexing the signal and pump. We demonstrate flat near-quantum-limited noise performance over 110 nm. Our low-power architecture enables practical on-chip OPAs for next-generation quantum and classical photonics.
