  Quantum transducers between microwave and optical photons are essential for
long-distance quantum networks based on superconducting qubits. An optically
active self-assembled quantum dot molecule (QDM) is an attractive platform for
the implementation of a quantum transducer because an exciton in a QDM can be
efficiently coupled to both optical and microwave fields at the single-photon
level. Recently, the transduction between microwave and optical photons has
been demonstrated with a QDM integrated with a superconducting resonator. In
this paper, we present a design of a QD-high impedance resonator device with a
low microwave loss and an expected large single-microwave photon coupling
strength of 100s of MHz. We integrate self-assembled QDs onto a high-impedance
superconducting resonator using a transfer printing technique and demonstrate a
low-microwave loss rate of 1.8 MHz and gate tunability of the QDs. The
microwave loss rate is much lower than the expected QDM-resonator coupling
strength as well as the typical transmon-resonator coupling strength. This
feature will facilitate efficient quantum transduction between an optical and
microwave qubit.
