IBM and Cisco partner to build networked quantum computers - SDxCentral

IBM and Cisco partner to build networked quantum computers Collaboration aims to build data center-scale links and the core components of distributed quantum computing November 27, 2025 By Berenice Baker, SDxCentral Have your say Facebook Twitter LinkedIn Reddit Email Share – Cisco IBM and Cisco are partnering to develop the hardware needed for networked quantum computers. The pair's initial focus is on high-efficiency transducers and optical links that could connect quantum processing units (QPUs) across data centers and, eventually, over kilometer-scale distances. The collaboration is intended to move beyond the limits of single processors and lay the groundwork for a future quantum computing internet.A recent IBM technical blog by Jerry Chow, CTO of quantum-centric supercomputing, outlined why modular and networked designs are becoming central to its roadmap. Chow told SDxCentral that monolithic approaches are approaching their limits.“A single chip can only scale so far before wiring density, thermal load, fabrication yield, and overall system complexity limit what you can achieve,” he said.Even IBM’s first fault-tolerant systems, Starling and Blue Jay, will rely on cryogenic interconnects tying multiple chips together inside a single refrigerator. Chow added that networking is the path beyond those constraints, saying: “Networked quantum computers let us expand useful circuit volume by stitching together multiple high-quality processors into a unified computational fabric.”He noted that large-scale applications in optimization, chemistry, materials, and medicine will require circuits with trillions of entangling gates, far beyond what any standalone fault-tolerant processor can support. IBM expects the first demonstrations of quantum advantage in 2026 and the arrival of fault-tolerant hardware in 2029, but Chow said distributed architectures will be needed to tackle the largest workloads.At the center of IBM’s approach is a new architectural element: the quantum networking unit, or QNU. This interface extracts “stationary” qubit states from a quantum processor and converts them into “flying” photonic qubits that can traverse a link.“Without a QNU, you cannot run coherent distributed quantum circuits,” Chow said.IBM aims to demonstrate entanglement between two cryogenically separated processors within five years.Cisco’s role is to help build the quantum network infrastructure around these QNUs. Vijoy Pandey, senior vice president and general manager at Outshift by Cisco, said the company is focusing on distributing entanglement resources between QNUs, enabling quantum teleportation between separate systems, and synchronizing operations with sub-nanosecond precision.“This challenge requires a full system approach, combining hardware, software, and network intelligence to make distributed quantum computing practical,” he said.The two companies are jointly exploring microwave-to-optical transducers, widely regarded as one of the most challenging engineering problems in quantum networking. These devices convert microwave photons generated by superconducting qubits into optical photons that can travel over fiber. Chow said the remaining obstacles include high-efficiency transduction, preserving coherence across the link, and developing the control stack needed for coordinated multi-QPU operations.Both companies frame quantum networking as a natural extension of their long-term strategies. Pandey said Cisco views distributed quantum systems as the “pragmatic way to accelerate practical quantum applications,” allowing the company to leverage its optical transport, secure networking, and orchestration capabilities.“Instead of waiting for large monolithic quantum machines, Cisco aims to connect smaller quantum processors into distributed systems,” he said.IBM is pursuing a tiered linking strategy across multiple distance scales. L-couplers connect chips inside a dilution refrigerator; medium-range microwave-frequency links developed with Fermilab’s SQMS center are designed for distances of one to 10 meters; and the long-distance optical links under exploration with Cisco aim to carry quantum information across kilometers via high-efficiency transducers and optical components.Cisco expects the first major milestone within five years: a proof-of-concept network of multiple quantum computers operating as a single distributed system. IBM’s timeline aligns closely with Cisco's. Chow explained that the company plans to entangle two cryogenically separated processors over the same period.“These are the breakthroughs we must achieve to move beyond standalone fault-tolerant systems toward truly networked quantum computers,” he said.Looking further ahead, both companies see networking as the key to unlocking new scales of capability. Chow said large-scale distributed systems will enable “computations across tens to hundreds of thousands of qubits, circuits involving trillions of quantum gates,” creating architectures that exceed what any individual fault-tolerant machine can achieve.Pandey pointed to early opportunities in secure communications and high-precision synchronization, arguing that quantum networking “brings practical quantum capabilities closer to reality” by enhancing both quantum-classical integration and classical network performance. Subscribe to HPC & Quantum for regular news round-ups, market reports, and more.