  We propose theory for reversible quantum transducer connecting
superconducting qubits and optical photons using acoustic waves in
piezoelectrics. The proposed device consists of integrated acousto-optic
resonator that utilizes stimulated Brillouin scattering for phonon-photon
conversion, and piezoelectric effect for coupling of phonons to qubits. We
evaluate the phonon-photon coupling rate, and show that the required power of
optical pump as well as the other device parameters providing full and faithful
quantum conversion are feasible for implementation with the state of the art
integrated acousto-optics.
