Compact and efficient quantum frequency conversion of a fiber-pigtailed single-photon source

TL;DR

This paper demonstrates a highly efficient, fiber-integrated quantum frequency converter that converts single photons from visible to telecom wavelengths while preserving their quantum properties, advancing quantum communication technology.

Contribution

It introduces a coherent frequency conversion scheme combining a fiber-coupled Lithium Niobate waveguide with a fiber-pigtailed quantum dot source, achieving high efficiency and photon quality preservation.

Findings

48.4% end-to-end conversion efficiency

Preservation of photon purity and indistinguishability

Successful conversion from 925.7 nm to telecom C-band

Abstract

Quantum frequency converters are key enabling technologies in photonic quantum information science to bridge the gap between quantum emitters and telecom photons. Here, we report a coherent frequency converter scheme combining a fiber-coupled nonlinear optical Lithium Niobate waveguide with a fiber-pigtailed single-photon source based on semiconductor quantum dots. Single and indistinguishable photons are converted from 925.7 nm to the telecommunication C-band, with a 48.4% end-to-end efficiency and full preservation of single-photon purity and indistinguishability. The integration of the two fiber-based modules achieving top-level performance represents an important step toward the practical interconnection of future quantum information processing systems operating at different wavelengths.