We present the latest developments carried on in Quandela, where solid-state based quantum light sources with increased performances and usability were realized, allowing for plug-and-play operation, portability and integration in commercial infrastructure.
Quantum light sources based on single-photon emitters are a core technology, which is expected to enable a multitude of emerging quantum-photonic applications with superior performance. As the development of sources is approaching a certain level of maturity, the important next step for quantum-network related applications is to distribute the generated photons in the most practical way. However, so far these remained within research facilities or were only transmitted over short specially installed fiber. In this regard, operation of the sources at standard telecom wavelengths such that existing classical communication infrastructure can be used, seems the most desirable solution.
Non-classical states of light play a fundamental role in quantum technology. From photonic quantum computers and simulators, to quantum communication and sensing, quantum states of light enable performing tasks that may outperform their best classical counterparts. Semiconductor quantum dots embedded in photonic nanostructures offer the most advanced classes of quantum light sources. Importantly, the underlying physics processes determining device performance are today fully understood, and dedicated engineering projects are currently advancing these sources towards real-world quantum technology applications. We review the performance of deterministic single-photon sources based on quantum dots in photonic crystal waveguides, the approach with the highest performance specs since it intrinsically combines suppression of leaky modes and Purcell enhancement to slow-light waveguide mode. Furthermore, we present prototype data from sources that today are commercially available and with performance metrics approaching the ideal.
Abstract Worldwide, enormous efforts are directed toward the development of the so‐called quantum internet. Turning this long‐sought‐after dream into reality is a great challenge that will require breakthroughs in quantum communication and computing. To establish a global, quantum‐secured communication infrastructure, photonic quantum technologies will doubtlessly play a major role, by providing and interfacing essential quantum resources, for example, flying‐ and stationary qubits or quantum memories. Over the last decade, significant progress has been made in the engineering of on‐demand quantum light sources based on semiconductor quantum dots, which enable the generation of close‐to‐ideal single‐ and entangled‐photon states, useful for applications in quantum information processing. This review focuses on implementations of, and building blocks for, quantum communication using quantum‐light sources based on epitaxial semiconductor quantum dots. After reviewing the main notions of quantum communication and introducing the devices used for single‐photon and entangled‐photon generation, an overview of experimental implementations of quantum key distribution protocols using quantum dot based quantum light sources is provided. Furthermore, recent progress toward quantum‐secured communication networks as well as building blocks thereof is summarized. The article closes with an outlook, discussing future perspectives in the field and identifying the main challenges to be solved.
Semiconductor quantum dots have emerged as an excellent platform for quantum light generation, providing quantum pure single photon wavepackets with unparalleled efficiency. These devices have started to accelerate the development of optical quantum technologies – notably in the field of optical quantum computing. In this talk, I will discuss our progresses toward the deterministic source, the use of these sources for the generation of linear cluster states and the generation of quantum light state using spontaneous emission as a resource for entanglement in the photon number basis.
Semiconductor quantum dots (QDs) have emerged as a premier solid-state platform for the deterministic generation of nonclassical light, offering a compelling pathway toward scalable quantum photonic systems. While single-photon emission from QDs has reached a high level of maturity, the realization of high-fidelity entangled photon-pair sources remains an active and rapidly evolving frontier. In this review, we survey the recent progress in QD-based entangled photon sources, highlighting the conceptual evolution from the established biexciton-exciton cascade to the emerging paradigm of spontaneous two-photon emission. We further examine how advances in nanophotonic architectures and coherent control strategies are redefining fundamental performance limits, enabling concurrent improvements in source brightness, coherence, and entanglement fidelity. Finally, we discuss the key physical and technological challenges that must be addressed to bridge the gap between laboratory demonstrations and large-scale deployment. We conclude by outlining the future opportunities for integrating QD-based entangled photon sources into practical quantum communication, computation, and sensing platforms.
A key element in the quickly developing science of photonic quantum information processing is quantum light sources. These sources are crucial for applications in quantum computing, quantum cryptography, and quantum communication because they can produce both single photons and entangled photon pairs. The efficiency, scalability, and performance of quantum light sources have been greatly enhanced by recent developments in four-wave mixing, spontaneous parametric down-conversion, and quantum dot technology. the most recent advancements in constructed quantum light sources, emphasizing how they help solve important problems including coherence, indistinguishability, and integration with current photonic systems. We explore how these sources can improve the fidelity and reliability of quantum circuits and how they could transform fault-tolerant quantum computing and secure communication networks in the future. In order to further the practical application of quantum technologies, the study also suggests potential paths for combining quantum light sources with scalable photonic systems.