An ultrahigh-impedance superconducting thermal switch for interfacing superconductors to semiconductors and optoelectronics

TL;DR

This paper introduces a superconducting switch capable of converting low-voltage inputs into high-voltage outputs suitable for semiconductor devices at cryogenic temperatures, enabling efficient interfaces for quantum and neuromorphic computing.

Contribution

The development of an ultrahigh-impedance superconducting switch that directly translates superconducting signals into semiconductor-compatible voltages at cryogenic temperatures.

Findings

Switch achieves >1 MΩ output impedance.

Turn-on time less than 300 ps, turn-off 15 ns.

Energy consumption of 0.18 fJ/μm².

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).