Development of a Microwave-to-Millimeter Wave Transducer

Scalability in superconducting quantum processors is limited by the challenge of efficiently linking physically separated systems. To address this, a superconducting device designed for quantum transduction between microwave and millimeter-wave frequencies has been proposed for building local quantum networks [1]. In this approach, the kinetic inductance nonlinearity is leveraged to resonantly convert microwaves to millimeter waves via four-wave mixing. However, due to the stark change in frequency, excitation and readout of such different frequencies simultaneously is challenging. In this work, we present details on our proposed packaging solution to mitigate these | challenges. The device packaging includes a low-loss coupling structure using tapered couplers [2] that supports three ports, corresponding to the three modes of the transducer. Details of the device packaging and preliminary experimental results that characterize the packaging will be presented.

(1) Pechal, M., & Safavi-Naeini, A. H. "Millimeter-wave interconnects for microwave-frequency quantum machines." Phys. Rev. A, 96, 042305 (2017). DOI: 10.1103/PhysRevA.96.042305

(2) Anferov, A., Harvey, S. P., Wan, F., Lee, K. H., Simon, J., & Schuster, D. I. "Low-loss millimeter-wave resonators with an improved coupling structure." Supercond. Sci. Technol., 37, 035013 (2024). DOI: 10.1088/1361-6668/ad22ff