Case studies — real-world quantum networks
Profiles of quantum networks that exist outside a single lab — built on deployed fibre, connecting more than one building or city, and either carrying real traffic or open to outside users. Each entry records who operates it, where it runs, the technology family (Entanglement, QKD, or Hybrid), the scale, the operating status, and the commercial model.
Use the search box and chips below to narrow the grid — for example, press Entanglement to hide the QKD-only entries, or Operational to filter out research demos and roadmap announcements.
All case studies
Entanglement
2022 · Metro (~8 km loop)
EPB Quantum Network (Chattanooga)
EPB · Qubitekk · Aliro · (IonQ from 2025)
Chattanooga, Tennessee, USA
First commercially-available quantum network in the US. Customer-configurable entangled-photon testbed on EPB dark fibre, with Aliro AliroNet as controller. IonQ trapped-ion system added under a $22 M deal in April 2025.
Open →2026 · Metro (17.6 km, 3-node hub-and-spoke)
Cisco × Qunnect Brooklyn–Manhattan metro entanglement-swap
Qunnect · Cisco · NYU · QTD Systems (GothamQ testbed)
Brooklyn ↔ 60 Hudson Street, New York City, USA
First metro-scale entanglement-swap over deployed commercial telecom fibre. Two Qunnect Carina warm-rubidium sources at Brooklyn end nodes; Bell-state-measurement hub at 60 Hudson Street with SNSPDs; Cisco control plane handling White Rabbit timing and polarization compensation. 5,400 swapped pairs/hour at >99 % fidelity. Announced 18 February 2026.
Open →2026 · Research prototype (single switch device)
Cisco Universal Quantum Switch (UQS)
Cisco (Santa Monica Quantum Labs); partners IBM, Qunnect, Atom Computing
Santa Monica, California, USA (lab)
Research prototype that routes quantum information between four photonic encodings — polarisation, time-bin, frequency-bin and path — via a Cisco-patented in-line conversion engine. Room-temperature on telecom fibre, 1 ns electro-optic switching, sub-watt power, ≤ 4 % per-conversion fidelity loss; announced 23 April 2026.
Open →2025 (announcement) — early 2030s target · Target: tens-to-hundreds of thousands of qubits across multiple cryostats
IBM × Cisco × SQMS Quantum Networking Units (QNU) plan
IBM · Cisco · Fermilab/SQMS
Multi-site (Yorktown Heights, Cisco labs, Fermilab)
Joint IBM, Cisco, and Fermilab/SQMS roadmap announced 20 November 2025 to network superconducting processors across multiple cryostats by the early 2030s, with a proof-of-concept targeted for end of 2030. The three named components — microwave-to-optical transducers, IBM Quantum Networking Units at each node, and inter-cryostat entanglement-distribution protocols — are open R&D problems, not deliverables.
Open →2025 · Two-module, ~2 m optical link
Oxford trapped-ion distributed-compute demonstration
University of Oxford (Lucas group) on lab-bench fibre
Oxford, UK (lab)
First distributed quantum algorithm executed across two physically separate quantum-computing modules. Heralded photonic entanglement between ⁸⁸Sr⁺ network qubits is swapped onto ⁴³Ca⁺ circuit qubits and consumed for a deterministic teleported CNOT (~86 % fidelity), with a two-qubit Grover's search run end-to-end across the link. Main et al., Nature (2025).
Open →2024 · Metro (35 km deployed loop)
Harvard SiV two-node Boston-metro loop
Harvard (Lukin / Lončar / Park) on Verizon fibre
Boston-Cambridge, Massachusetts, USA
Heralded entanglement between two silicon-vacancy quantum-memory nodes through 35 km of installed telecom fibre under a Boston urban environment. Published as Knaut et al., Nature 629.573 (2024).
Open →2021 · Lab-scale three-node chain
Delft three-node NV-centre network
QuTech / TU Delft (Hanson group)
Delft, Netherlands
First entanglement-based three-node network with two non-neighbouring endpoints linked by a midpoint repeater node. Demonstrated entanglement distribution and entanglement swapping (Pompili et al., Science 372.259, 2021); a 2022 follow-up added qubit teleportation between non-neighbours.
Open →QKD
2017 · National trunk (~2,032 km, 32 trusted nodes)
Beijing–Shanghai QKD backbone
USTC / QuantumCTek / state operators
Beijing ↔ Jinan ↔ Hefei ↔ Shanghai, China
The longest deployed terrestrial QKD trunk. Trusted-node relay between four cities, integrated with the Micius satellite for a 4,600 km space–ground link. Not entanglement-based — keys are reconstructed at each trusted relay.
Open →2022– · ~23 kg microsatellite; satellite-to-ground QKD
Jinan-1 quantum microsatellite
USTC · JIQT · SECM · Hefei National Lab
LEO (~500 km); ground stations across China
Engineering follow-up to Micius: a small-bus microsatellite carrying a decoy-state BB84 transmitter with real-time on-board key sifting, designed as a precursor to a low-cost quantum-satellite constellation. Launched 27 July 2022, operates as the space segment of the Jinan metropolitan QKD network (Li et al., Nature 2025).
Open →2021– · Metro (9 nodes, 28 QKD modules)
MadQCI — Madrid Quantum Communications Infrastructure
UPM / Telefónica / Huawei / partners
Madrid metro, Spain
Europe's largest and longest-running QKD testbed. Nine SDN-managed nodes co-existing with commercial Telefónica traffic; supports multiple QKD vendors and ETSI-aligned key management. Documented in Martin et al., npj QI 10.80 (2024).
Open →2022 · Metro (London ring)
BT–Toshiba London commercial QKD metro
BT · Toshiba (first customer: EY)
London, UK
First commercial QKD-secured metro network sold as a service in the UK. Toshiba supplies the QKD hardware; BT operates the fibre and managed service. EY connected its Canary Wharf and London Bridge offices as the launch customer.
Open →2024 · Metro hub-and-spoke (Falqon hub in Eurofiber DC + Port Authority and Customs end nodes)
Q*Bird Port of Rotterdam MDI-QKD pilot
Q*Bird · Single Quantum · Cisco · Eurofiber · Port of Rotterdam Authority (under Quantum Delta NL)
Port of Rotterdam, Netherlands
First multi-node MDI-QKD pilot in a working industrial port. Q*Bird's Falqon hub installed in a Eurofiber data centre performs Bell-state measurements between photons from Port of Rotterdam Authority and Dutch Customs end nodes — moving detector trust out of the end users' premises into a neutral middle. QUEST follow-on extends the architecture across South Holland.
Open →No case studies match the current filters.