Quantum interference in heterogeneous superconducting-photonic circuits on a silicon chip

TL;DR

This paper demonstrates a scalable hybrid superconducting-photonic circuit on a silicon chip, achieving high-visibility quantum interference and integrated photon detection, advancing the development of large-scale quantum photonic systems.

Contribution

It introduces a hybrid superconducting-photonic circuit system on silicon, combining quantum interference and detection in a scalable, integrated platform.

Findings

97% interference visibility with integrated detectors

Compatible with standard semiconductor fabrication

Demonstrated on-chip photon interference and detection

Abstract

Quantum information processing holds great promise for communicating and computing data efficiently. However, scaling current photonic implementation approaches to larger system size remains an outstanding challenge for realizing disruptive quantum technology. Two main ingredients of quantum information processors are quantum interference and single-photon detectors. Here we develop a hybrid superconducting-photonic circuit system to show how these elements can be combined in a scalable fashion on a silicon chip. We demonstrate the suitability of this approach for integrated quantum optics by interfering and detecting photon pairs directly on the chip with waveguide-coupled single-photon detectors. Using a directional coupler implemented with silicon nitride nanophotonic waveguides, we observe 97% interference visibility when measuring photon statistics with two monolithically integrated superconducting single photon detectors. The photonic circuit and detector fabrication processes are compatible with standard semiconductor thin-film technology, making it possible to implement more complex and larger scale quantum photonic circuits on silicon chips.