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arXiv:2602.02653

Direct telecom network between atomic and solid-state quantum nodes

Yuzhou Chai, Dahlia Ghoshal, Nayana P. Tiwari, Alexander Kolar, Benjamin Pingault, Hannes Bernien, Tian Zhong

quant-phSubmitted Feb 2, 2026• Announced Feb 4, 2026• 0 citations
v1 · Feb 2, 2026v2 · Mar 6, 2026
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Abstract

Future quantum networks will interconnect quantum systems with distinct functionalities, ideally over long distances via low-loss telecom optical fibers. Here, we realize a two-node hybrid network that directly connects an atomic single photon source to a solid-state quantum memory in the telecom C-band without the need of frequency conversion and external filtering. Both nodes exhibit state-of-the-art performance at 1530 nm: the source achieves a heralded auto-$g^{(2)}(0)$ = 0.031 at a photon rate of 46 kcps, and the memory a storage efficiency of 10.6% with high multimode capacity. We leverage the intrinsic tunability of both nodes to optimize spectral matching, enabling direct networking between the two: single-photon storage and retrieval for 1 $μ$s over up to 37 temporal modes across extended fibers of 10.6 km (metropolitan) and 49.2 km (laboratory) while preserving non-classicality. These results define a high-bandwidth source-memory link that operates natively in the telecom band, introducing a new paradigm for the design and scaling of hybrid quantum networks.

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Future quantum networks will interconnect quantum systems with distinct functionalities, ideally over long distances via low-loss telecom optical fibers. Here, we realize a two-node hybrid network that directly connects an atomic single photon source to a solid-state quantum memory in the telecom C-band without the need of frequency conversion and external filtering. Both nodes exhibit state-of-the-art performance at 1530 nm: the source achieves a heralded auto-g(2)(0)g^{(2)}(0)g(2)(0) = 0.031 at a photon rate of 46 kcps, and the memory a storage efficiency of 10.6% with high multimode capacity. We leverage the intrinsic tunability of both nodes to optimize spectral matching, enabling direct networking between the two: single-photon storage and retrieval for 1 μμμs over up to 37 temporal modes across extended fibers of 10.6 km (metropolitan) and 49.2 km (laboratory) while preserving non-classicality. These results define a high-bandwidth source-memory link that operates natively in the telecom band, introducing a new paradigm for the design and scaling of hybrid quantum networks.
Quantum networking enables the distribution of quantum information across distant nodes, unlocking capabilities such as secure communication, distributed quantum computing, enhanced metrology, and tests of fundamental physics. Photons serve as the natural carriers of quantum information over long distances due to their low loss in optical fibers and robustness to environmental decoherence. However, the practical realization of quantum networks remains limited by the lack of photon sources that are simultaneously compatible with diverse quantum systems, stable over long timescales, and suitable for deployment in real-world fiber infrastructure. This dissertation addresses these challenges through the co-development of photon-pair sources and a field-deployed quantum networking testbed. We present two complementary chip-scale sources of correlated photon pairs tailored for distinct bottlenecks in quantum networking. The first is a hybrid visible–telecom photon-pair source designed to address a fundamental spectral mismatch between quantum nodes and communication channels. While most quantum memories and processors operate at visible to near- nfrared wavelengths, optical fibers exhibit minimal loss in the telecommunications band. By integrating periodically poled nonlinear waveguides with photonic integrated circuits, we demonstrate a platform capable of directly generating visible–telecom photon pairs, enabling efficient interfacing between heterogeneous quantum systems and existing fiber networks. The second source is a fully packaged, broadband telecom photon-pair source based on silicon waveguide spirals, designed for stable, long-duration operation. This stability enables extended measurements necessary to overcome channel losses and environmental drifts in deployed fiber networks. These sources are evaluated within RoQNET (Rochester Quantum Network), a ∼20 km fiber link between the Rochester Institute of Technology and the University of Rochester. Using this platform, we demonstrate the transmission and on-chip modulation of heralded telecom single photons, verify their nonclassical statistics, and characterize long-term channel behavior. Additionally, we explore programmable time-bin entanglement distribution using spectral waveshapers, providing a flexible approach to quantum communication. Together, this work establishes a co-designed source–network framework for scalable, heterogeneous quantum networking.
The quantum internet is envisioned to enable transformative applications such as distributed quantum computing, quantum-enhanced distributed sensing, precise clock distribution, and secure communication. However, the development of the envisioned quantum internet hinges upon high performance quantum memories (QMs). Rare-earth ions doped in solids are among the promising candidates for realizing QMs due to high multimode storage capability, long coherence time and high storage efficiency. In this work, we demonstrate a practical solid-state memory using Erbium ions (Er3+), operating at telecom wavelengths (1536 nm) compatible with existing fiber-optic infrastructure. We showcase on-demand storage and retrieval of weak coherent pulses for up to 1 ms, the longest storage time using Er\textsuperscript{3+} reported in the literature. Crucially, our storage protocol operates without involving spin-level transitions, simplifying the system design and improving its robustness. We further showcase a temporal and spectral multimode capacity with selective recall capabilities, essential for a scalable quantum repeater architecture.
Scalable quantum networks require the efficient generation and storage of entanglement between photonic qubits and quantum memories. Quantum repeaters based on absorptive rare-earth-ion photonic memories offer a promising route toward highly multiplexed quantum networking, but unifying spectrally matched photon sources and quantum memories within a common architecture remains a major challenge. Here we demonstrate an integrated photonic architecture for telecom photon-memory entanglement generation based on dual self-similar silicon carbide microring resonators. Connected by a fiber link, one resonator operates as an entangled photon-pair source, while the other functions as a cavity-enhanced atomic-frequency-comb quantum memory. The memory resonator reaches an ensemble cooperativity of 1.9 after hyperfine initialization and is spectrally matched to the source, enabling storage of entangled telecom photons without spectral modification. We generate and characterize photon-memory entanglement from a quantum interference visibility preserved before and after storage. Harnessing the strong source correlations and the high multimode capacity of the memory, we access high-dimensional entanglement spanning 63 temporal modes, reaching a maximum photon information efficiency of 5.1 Ebits per detected photon and a peak on-chip photon-memory entanglement rate of 5.6 kEbits per second. These results establish a route toward chip-scale quantum networking hardware operating over telecommunications infrastructure.
Abstract Reliable quantum communication over hundreds of kilometers is a daunting yet necessary requirement for a quantum internet. To overcome photon loss, the deployment of quantum repeater stations between distant network nodes is necessary. A plethora of different quantum hardware is being developed for this purpose, each platform with its own opportunities and challenges. Here, we propose to combine two promising hardware platforms in a hybrid quantum repeater architecture to lower the cost and boost the performance of long-distance quantum communication. We outline how ensemble-based quantum memories combined with single-spin photon transducers, which can transfer quantum information between a photon and a single spin, can facilitate massive multiplexing, efficient photon generation, and quantum logic for amplifying communication rates. As a specific example, we describe how a single Rubidium (Rb) atom coupled to nanophotonic resonators can function as a high-rate, telecom-visible entangled photon source with the visible photon being compatible with storage in a Thulium-doped crystal memory (Tm-memory) and the telecom photon being compatible with low loss fiber propagation. We experimentally verify that Tm and Rb transitions are in resonance with each other. Our analysis shows that by employing up to 9 repeater stations, each equipped with two Tm-memories capable of holding up to 625 storage modes, along with four single Rb atoms, one can reach a quantum communication rate of about 10 secret bits per second across distances of up to 1000 km.
Processing and distributing quantum information using photons through fibre-optic or free-space links are essential for building future quantum networks. The scalability needed for such networks can be achieved by employing photonic quantum states that are multiplexed into time and/or frequency, and light-matter interfaces that are able to store and process such states with large time-bandwidth product and multimode capacities. Despite important progress in developing such devices, the demonstration of these capabilities using non-classical light remains challenging. Here, employing the atomic frequency comb quantum memory protocol in a cryogenically cooled erbium-doped optical fibre, we report the quantum storage of heralded single photons at a telecom-wavelength (1.53 μm) with a time-bandwidth product approaching 800. Furthermore, we demonstrate frequency-multimode storage and memory-based spectral-temporal photon manipulation. Notably, our demonstrations rely on fully integrated quantum technologies operating at telecommunication wavelengths. With improved storage efficiency, our light-matter interface may become a useful tool in future quantum networks.
Abstract To advance the full potential of quantum networks one should be able to distribute quantum resources over long distances at appreciable rates. As a consequence, all components in the networks need to have large multimode capacity to manipulate photonic quantum states. Towards this end, a multimode photonic quantum memory, especially one operating at telecom wavelength, remains a key challenge. Here we demonstrate a spectro-temporally multiplexed quantum memory at 1532 nm. Multimode quantum storage of telecom-band heralded single photons is realized by employing the atomic frequency comb protocol in a 10-m-long cryogenically cooled erbium doped silica fibre. The multiplexing encompasses five spectral channels - each 10 GHz wide - and in each of these up to 330 temporal modes, resulting in the simultaneous storage of 1650 modes of single photons. Our demonstrations open doors for high-rate quantum networks, which are essential for future quantum internet.