Compact system development of efficient quantum-entangled photon sources towards deployable and industrial devices

TL;DR

This paper presents a modular, rack-based quantum light source using semiconductor quantum dots, achieving high entanglement quality, stability, and brightness suitable for industrial deployment.

Contribution

It introduces a standardized, automated, and industry-compatible system architecture for efficient, stable, and deployable entangled photon sources based on quantum dots.

Findings

Achieved entanglement negativity up to 0.98, confirming near-maximal entanglement.

Maintained high brightness with an average emission rate of 697 kHz over six hours.

Demonstrated long-term stable operation with consistent entanglement quality.

Abstract

Entangled photon pair sources are a key enabling technology for quantum communication and networking, yet their deployment beyond laboratory environments is hindered by system-level complexity, limited operational stability, and insufficient industry compatibility. Here, we demonstrate a rack-based, mobile quantum light source architecture based on a semiconductor quantum dot emitter that directly addresses these challenges through modular system integration and automated operation. The source generates polarization-entangled photon pairs with an entanglement negativity 2n of up to $0.98(1)$, confirming near-maximal entanglement quality. In continuous, hands-off operation over a six-hour time window, the system achieves an average single-photon emission rate of $697(8)$ kHz and a maximum rate of $740(7)$ kHz, while maintaining 2n-value of more than $95$ $\%$. These results are enabled by the integration of optical excitation, collection, cryogenic operation, and control electronics within a standardized rack footprint, together with automated monitoring. By demonstrating simultaneously high entanglement quality, sustained brightness, and long-term operational stability in an industry-aligned system architecture, this work advances semiconductor quantum dot sources toward deployable entangled photon sources for applied quantum photonics.