High-quality multi-wavelength quantum light sources on silicon nitride micro-ring chip

TL;DR

This paper demonstrates a high-quality, multi-wavelength quantum light source on a silicon nitride micro-ring chip, capable of generating heralded single photons and entangled photon pairs at telecom wavelengths, suitable for quantum networks.

Contribution

The work introduces a CMOS-compatible silicon nitride micro-ring device producing multiple correlated photon pairs with high purity and entanglement at room temperature.

Findings

Generated eight pairs of correlated photons within 25.6 nm range

Achieved heralded single-photon rate of 62 kHz with low $g^{(2)}_{h}(0)$

Produced energy-time entangled photons with 99.39% visibility

Abstract

Multi-wavelength quantum light sources, especially at telecom band, are extremely desired in quantum information technology. Despite recent impressive advances, such a quantum light source with high quality remains challenging. Here we demonstrate a multi-wavelength quantum light source using a silicon nitride micro-ring with a free spectral range of 200 GHz. The generation of eight pairs of correlated photons is ensured in a wavelength range of 25.6 nm. With device optimization and noise-rejecting filters, our source enables the generation of heralded single-photons - at a rate of 62 kHz with $g^{(2)}_{h}(0)=0.014\pm0.001$, and the generation of energy-time entangled photons - with a visibility of $99.39\pm 0.45\%$ in the Franson interferometer. These results, at room temperature and telecom wavelength, in a CMOS compatible platform, represent an important step towards integrated quantum light devices for the quantum networks.