The Light Switch: How Photonics Could Revolutionize Data Centre Efficiency

Why Copper is No Longer Cutting It

When I first entered the data centre industry in the early 2010s, copper was still king. Every server rack, every cable tray, and even the cooling systems relied heavily on this metal that had powered computing for decades. Today, we're seeing signs of change—data centres are beginning to reconsider their dependence on copper, not because it's running out, but because its limitations are becoming too costly to ignore.

Take Digital Reality's chief technology officer, Chris Sharp, who recently told me that "I think we're at the end of copper". What he meant wasn't a depletion of supply but a strategic pivot toward more efficient alternatives. And indeed, the scale of copper use in these facilities is staggering—up to 400 tonnes in a typical 100MW data centre.

Most of that goes into electrical infrastructure and cooling systems, but around 70 tonnes are dedicated to server interconnects alone. An additional 20 tonnes are used for network wiring that connects these servers—where the most promising innovations may lie.

Lighting the Way Forward

The shift toward using light instead of electrons is not new. For decades, optical fibre has been the backbone of long-distance communications, carrying vast quantities of data across continents at near-light speeds. However, it's only recently that researchers and tech companies have started exploring how to bring this efficiency inside data centres.

This approach is called photonics. By using photons rather than electrons, the technology promises several advantages: reduced heat generation, lower energy requirements for cooling, and even greater bandwidth. As Callum Littlejohns of Cornerstone Labs notes, "You can save so much energy".

"What's happening now with optics and photonics is there's kind of a reset," says Peter O'Brien from Ireland's Tyndall Research Institute. "It's not just a new trend; it's a reimagining of how we connect components."

This technological shift is being supported by industry giants like Nvidia, which has made significant investments in photonics to power its AI chips and data processing units.

Engineering a Revolution

Switching from copper to photonics isn't as simple as plugging in new cables. It requires integrating optical components directly with electronic systems—sometimes even onto the computer chips themselves. This hybrid approach demands expertise across multiple engineering disciplines and supply chains that were previously separate.

Andrew Wheeler of Hewlett Packard Labs explains that while we've mastered electrical system design, manufacturing, testing, and deployment, the same is not yet true for photonics. The complexity lies in bridging these two worlds.

Moreover, manufacturing photonics components involves different processes and often requires global coordination. Final assembly is often handled by specialized packaging houses located primarily in Taiwan, making supply chain management more intricate.

Thermal Challenges

One major concern is heat sensitivity. While optical networks themselves generate far less heat than their electrical counterparts, they remain vulnerable to thermal stress. Other components inside the data centre still produce significant heat, creating an environment where optical devices may fail if not carefully controlled.

This means reliability becomes paramount. Data centre operators must maintain strict thermal limits—something that's particularly challenging given the current infrastructure and operational protocols.

Skills and Scalability

The transition also brings human factors into play. Field support engineers, installers, and network designers all need to learn new skills to work with photonics systems. As Sharp puts it: "You can't take tight turns. There are little nuances on how to structure that."

These challenges extend beyond just technical know-how—they touch on training, operational readiness, and even the economics of scaling up production.

The Future of Optical Processing

Ultimately, the full potential of photonics will be realized when light is used not only to carry data but also to process it. Ofer Shapiro of Resolight.ai argues that converting data between photons and electrons repeatedly is inefficient and energy-intensive.

His company is developing architectures that replace traditional electronic switches with all-optical devices. The goal? To keep data in the optical domain throughout its journey, reducing energy loss and improving speed.

"It doesn't make sense to constantly convert data from photons to electrons and back," Shapiro says. "Optical interconnects between chips and network elements would mean data remains in the optical domain, saving even more energy."

This vision may still be years away, but it's one that's already influencing current development efforts.

Manufacturing at Scale

To make photonics economically viable on a large scale, manufacturers are turning to legacy tools and adapting them for new purposes. Cornerstone Labs, for instance, repurposes old silicon fabrication equipment used in earlier generations of processors—from Intel's Pentium 4 chips, to create photonics components.

This reuse of knowledge and infrastructure could significantly reduce the cost of photonics production and accelerate adoption. As Littlejohns emphasizes, "We know we can make it at a huge scale, so that's why it's such an interesting technology, because it can underpin many applications."

Implications for Global Business

As global computing demands continue to grow, especially driven by AI and machine learning, the energy efficiency of data centres will become even more critical. The shift from copper to photonics isn't just about technology—it's a response to the economic pressures and environmental realities that define modern business.

While challenges remain in manufacturing, deployment, and workforce training, the promise of reduced energy consumption and increased bandwidth offers a compelling case for investment. For investors, policymakers, and data centre operators alike, this represents an opportunity to future-proof infrastructure while minimizing costs and carbon footprints.