10 December 2025

^{The Nu Quantum team} 

 

When a deep-tech startup announces one of the biggest Series A rounds in Europe this year, the number tends to dominate the headline. But in the case of Cambridge-based Nu Quantum, the size of the round matters less than the problem it aims to solve. The company has raised $60 million to tackle one of quantum technology’s most persistent engineering challenges: distributing entanglement between multiple quantum machines in a controlled and repeatable way.

Quantum computing often appears as a race toward a single, breakthrough device. Nu Quantum belongs to a growing group taking a different approach. Instead of building a bigger processor, the company is trying to connect smaller quantum computers through a photonic network. Its hardware—what it calls an “Entanglement Fabric”—is designed to link quantum processors so they can share quantum states and operate in coordination. In classical terms, it’s the equivalent of moving from isolated mainframes to distributed systems.

That shift explains both the attention and the funding. Quantum networking is not a hypothetical future capability; it’s a tractable engineering problem that builds on mature photonics, telecom infrastructure, and decades of knowledge about optical systems. The hard part is integrating these components into something robust enough for industrial use, and that is the gap Nu Quantum is trying to close.

Building hardware, not abstractions

Nu Quantum’s pitch stands out because it deals in concrete, engineering-focused quantum infrastructure rather than high-level promise. The company does not build quantum computers; it builds the photonic modules that allow different quantum devices—trapped-ion systems, superconducting qubits, silicon spin qubits, and others—to exchange entangled photons. The network layer is deliberately qubit-agnostic. Just as early internet standards worked across differing computer architectures, Nu Quantum aims to provide an interoperable layer that any quantum processor can plug into.

This philosophy shows up in its testing approach. Rather than isolated demonstrations in lab conditions, the modules are designed to operate alongside cryogenic hardware, commercial telecom components, and installed fiber with known imperfections. Engineers spend as much time dealing with thermal drift, alignment stability, and noise in optical fiber as they do on quantum performance. It’s the work that determines whether a technology can survive outside a physics lab.

This is one of Nu Quantum’s key differentiators. Many academic proofs-of-concept work beautifully for a few hours on an optical table. Nu Quantum’s goal is to build something that runs for months without a researcher tuning it “like a musical instrument,” as one partner described early prototypes. That shift from experiment to product is often where deep tech struggles. The company is placing most of its Series A funding directly into that transition.

Why quantum networks matter now

The intuitive way to scale quantum computing is to add more qubits to a single machine. But qubits are fragile, and scaling often creates more noise and complexity than it resolves. Connecting smaller processors through a quantum network can avoid these bottlenecks by distributing workloads rather than forcing all computation into one device.

Quantum networking also enables capabilities that don’t depend on large, monolithic quantum computers. Entanglement distribution supports secure communication protocols, correlated sensing, and experiments that require shared quantum states across distance. Several European initiatives already incorporate these use cases, and Nu Quantum has participated in early deployments with telecom operators and national labs. These projects provide practical testbeds for understanding how entangled photons behave inside real-world telecom infrastructure.

The key point is that quantum networking builds directly on photonics engineering, an area where industry already has decades of expertise. While the quantum aspects are nontrivial, the supporting technologies involve lasers, detectors, timing electronics, and fabrication techniques that are well established. The challenge is integration at scale, not theoretical feasibility.

A distinctly European deep-tech story

Nu Quantum’s trajectory is shaped by its environment. The company grew out of a Cambridge ecosystem with deep roots in photonics and quantum optics. Several nearby companies have already shown how to take delicate optical technologies and turn them into manufacturable products. That local culture matters: proximity to experienced engineers shortens the path from prototype to production and creates pressure to deliver systems that work reliably, not just impress in the lab.

The European industrial context also plays a role. Europe has world-class quantum research but historically lagged in commercializing it. Recent investments aim to change that, especially in foundational technologies like quantum computing, photonics, and advanced manufacturing. Nu Quantum’s work fits directly into this agenda because networking is essential infrastructure for any region aiming to build full-stack quantum systems.

Nu Quantum already collaborates with national labs, campus-scale testbeds, and telecom operators responsible for critical infrastructure. These partnerships matter because quantum networking is fundamentally a systems challenge. Everything affects performance: temperature variations in buried fiber, vibration from HVAC systems near optical racks, timing drift, and integration constraints. Working with established industrial partners forces Nu Quantum to design for the conditions its network modules will actually encounter.

What the funding enables

The $60 million round is aimed squarely at scaling from prototypes to deployable systems. That means expanding manufacturing capacity for entanglement-generation modules; increasing engineering teams focused on packaging, stabilization, and control; and accelerating field trials with partners ready to integrate early production units.

Much of this revolves around reliability. In a lab, researchers can compensate for drift or noise manually. In the field, corrections must be automated. Better mechanical design, more stable photonic integration, and tighter timing synchronization are what turn a scientific demonstration into a viable product. That is where most of the capital is going.

The company is also preparing longer-distance tests, placing nodes in different buildings or, eventually, different cities. These trials are not primarily about distance—they are about demonstrating that a quantum network can operate inside real telecom infrastructure, which was never designed for single-photon transmission.

A clear, grounded direction in a noisy landscape

The quantum ecosystem produces plenty of dramatic claims, and it can be difficult to separate what is achievable today from what hinges on future breakthroughs. Nu Quantum’s approach stands out precisely because it avoids hype. The company is not promising quantum advantage or positioning itself against classical supercomputers. It is building the network layer quantum computing will require regardless of which qubit technologies prevail.

More importantly, it is doing so through steady engineering rather than abstraction. The Entanglement Fabric is not a vision statement; it is hardware under development, being tested with real partners, and designed to operate within the constraints of today’s infrastructure. The company’s new funding allows it to move from a promising prototype toward a reliable system and to do so with the pace and discipline industry expects.

If the last decade of quantum research was about proving concepts, the next decade will be about connecting them. Nu Quantum’s work suggests that progress will come not from a single revolutionary machine but from a distributed quantum network linking many. And for now, that network is being built the only way complex infrastructure ever is: one engineered module at a time.