On-chip quantum interference between silicon photon-pair sources

TL;DR

This paper demonstrates on-chip quantum interference between two silicon photon-pair sources integrated within a reconfigurable waveguide circuit, achieving high-visibility interference crucial for scalable quantum photonic technologies.

Contribution

It presents the first integration of two photon sources with a reconfigurable interferometer on silicon, enabling high-visibility quantum interference on-chip.

Findings

Achieved up to 100% on-chip quantum interference visibility.

Demonstrated manipulation of two-colour and same-colour photon pairs.

Reduced reliance on external photon sources for quantum circuits.

Abstract

Large-scale integrated quantum photonic technologies will require the on-chip integration of identical photon sources with reconfigurable waveguide circuits. Relatively complex quantum circuits have already been demonstrated, but few studies acknowledge the pressing need to integrate photon sources and waveguide circuits together on-chip. A key step towards such large-scale quantum technologies is the integration of just two individual photon sources within a waveguide circuit, and the demonstration of high-visibility quantum interference between them. Here, we report a silicon-on-insulator device combining two four-wave mixing sources, in an interferometer with a reconfigurable phase shifter. We configure the device to create and manipulate two-colour (non-degenerate) or same-colour (degenerate), path-entangled or path-unentangled photon pairs. We observe up to 100.0+/-0.4% visibility quantum interference on-chip, and up to 95+/-4% off-chip. Our device removes the need for external photon sources, provides a path to increasing the complexity of quantum photonic circuits, and is a first step towards fully-integrated quantum technologies.