Converting between 7-8.5 GHz and 21-24 GHz photons with a two-mode flux-tunable Josephson dipole

Large detuning between a transmon and its readout resonator has been shown to dramatically reduce the occurrence of nonlinear transitions that can bring the qubit out of the computational space. For a standard Al transmon in the 5-7 GHz frequency range, a high-frequency readout resonator can be designed to have up to 20 GHz of detuning from the qubit. However, commonly used readout electronics and superconducting parametric amplifiers operate in the 7-10 GHz band. In this talk, we experimentally demonstrate the operation of a two-mode flux-tunable Josephson dipole as a frequency converter. The dipole has a low-frequency mode which can be tuned in the 7-9.5 GHz band and a high-frequency mode which correlatively tunes in the 21-28 GHz band. By pumping the dipole at the frequency difference between the two modes at different external fluxes, exploiting the strong three-wave-mixing coupling between them, we demonstrate a flux-tunable microwave converter between 7-8.5 GHz and 21-24 GHz photons.