IBM and Cisco have announced plans to jointly build a distributed quantum computing network capable of linking fault-tolerant systems over long distances. In an announcement on Thursday, November 20, the companies said they aim to demonstrate a two-machine entanglement proof-of-concept by 2030, with the ultimate goal of enabling scalable quantum workloads that span multiple sites and processors. If successful, the collaboration would mark a shift in how quantum computing resources are deployed, moving beyond single-system scale to a federated architecture capable of trillions of quantum operations.
The initiative will combine IBM’s superconducting qubit hardware with new networking infrastructure from Cisco, including microwave-optical transducers, quantum network control layers, and physical and software routing protocols designed for entangled quantum state transmission.
The proposed architecture is intended to support fault-tolerant quantum computers already in IBM’s development roadmap. But it would also require the creation of new intermediary hardware — a planned ‘Quantum Networking Unit’, or QNU — to interface with IBM’s quantum processors and translate static quantum states into flying qubits suitable for transmission via photonic links.
The architecture IBM and Cisco want to build
The duo’s ambitions will be built upon a three-tier model that splits qubit modules, networking transduction interfaces, and optical entanglement layers. IBM’s Quantum Processing Unit (QPU) roadmap projects logical fault-tolerant machines with several hundred logical qubits. each requiring thousands of physical qubits, by 2030.
Cisco’s role is to link these cryogenic environments together. Entanglement between processors would be achieved using shared photon pairs or teleportation-style protocols, with photon-based carriers transmitted over optical fiber or potentially free-space links.
Because IBM’s superconducting qubits operate in the microwave scale, while long-distance transmission favors optical frequencies, a high-efficiency transducer is needed to convert quantum information from one format to another. That device — capable of preserving coherence and phase relationships between microwave and optical domains — will have to be developed and is one of the key technical hurdles of the roadmap.
The companies say the initial milestone will be to link two independent QPUs located in separate cryogenic systems. This will test both hardware entanglement and software synchronization layers. If successful, a scaled version of the architecture would allow for modular quantum computing networks, where computation is distributed across many small fault-tolerant nodes, and entanglement is dynamically allocated based on the structure of the problem being solved.
An image of Cisco’s Quantum Networking Entanglement Chip. (Image credit: Cisco)
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