Towards Quantum Limited Amplification of Phonons via Acosutoelectric Three-Wave Mixing

Parametric amplification is a proven low-noise amplification technique that, when in a phase sensitive configuration, can amplify the in-phase quadrature with a quantum-limited noise figure of 0 dB. Traveling wave parametric amplifiers in the RF regime are the state of the art when it comes to improving the SNR of superconducting qubit measurements. We utilize recent advances in heterogenously integrated acoustoelectric devices to demonstrate first-ever phononic parametric amplification utilizing large $\chi^{(2)}$ nonlinearities previously found in a 5 micron thick film of lithium niobate on silicon substrate. In contrast to previous acoustoelectric amplifiers, these parametric amplifiers do not require a bias voltage to exhibit gain, instead relying on greatly enhanced three-wave phonon mixing due to phonon-electron interactions. This drastically reduces joule heating in the system and makes them a promising candidate for cryogenic on-chip amplifiers. We demonstrate phononic parametric amplification at 500 MHz in InGaAs-TFLN-Si heterostructures with 14.2 dB of phase-sensitive gain at room temperature. We discuss extensions to 2D electron gases and cryogenic devices with an focus on quantum applications.