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

• Published in: Nature electronics Vol. 2; no. 10
• Main Authors: McCaughan, A N, Verma, V B, Buckley, S, Allmaras, J P, Kozorezov, A G, Tait, A N, Nam, S W, Shainline, J M
• Format: Journal Article
• Language: English
• Published: England 2019
• ISSN: 2520-1131
• DOI: 10.1038/s41928-019-0300-8

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 (1K 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 1K 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 1MΩ), and energy requirements (0.18fJ/ m ,3.24mV/nW).