Bidirectional microwave-optical transduction based on bulk acoustic resonators-silicon nitride integrated photonics co-integration

Coherent interfaces between microwave and optical frequencies are key components to weave networks of quantum systems for communication, sensing and computing. In this context, we will present the experimental characterization of a bidirectional microwave-optical frequency converter based on monolithic integration of piezoelectric actuators on silicon nitride photonic integrated circuits. The silicon substrate is released to confine high-overtone bulk acoustic waves in a silicon oxide cladding, leading to enhanced electromechanical and stress-optic couplings. The optical waveguides are fabricated using the photonic Damascene process, enabling simultaneously tight mode confinement and high quality factors while maintaining flexibility in dispersion engineering. The broadband transduction assisted by multiple acoustic modes paves the way toward the realization of an optically controlled arbitrary waveform generator for quantum applications.