A superconducting thermal switch with ultrahigh impedance for interfacing superconductors to semiconductors

McCaughan,, Adam and V. B. Verma and Buckley, S. M. and J. P. Allmaras and Kozorezov, Alexander and A. N. Tait and S. W. Nam and J. M. Shainline (2019) A superconducting thermal switch with ultrahigh impedance for interfacing superconductors to semiconductors. Nature Electronics, 2. pp. 451-456. ISSN 2520-1131

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Abstract

A number of current approaches to quantum and neuromorphic computing use superconductors as the basis of their platform or as a measurement component, and will need to operate at cryogenic temperatures. Semiconductor systems are typically proposed as a top-level control in these architectures, with low-temperature passive components and intermediary superconducting electronics acting as the direct interface to the lowest-temperature stages. The architectures, therefore, require a low-power superconductor-semiconductor interface, which is not currently available. Here we report a superconducting switch that is capable of translating low-voltage superconducting inputs directly into semiconductor-compatible (above 1,000 mV) outputs at kelvin-scale temperatures (1 K or 4 K). To illustrate the capabilities in interfacing superconductors and semiconductors, we use it to drive a light-emitting diode (LED) in a photonic integrated circuit, generating photons at 1 K from a low-voltage input and detecting them with an on-chip superconducting single-photon detector. We also characterize our device's timing response (less than 300 ps turn-on, 15 ns turn-off), output impedance (greater than 1 M{\Omega}), and energy requirements (0.18 fJ/um^2, 3.24 mV/nW).