TECH

Why might photonics be the key to reducing energy and water consumption in artificial intelligence?
A new report has identified photonics as the only viable solution to meet the rapidly growing energy demands driven by artificial intelligence (AI) without increasing carbon emissions. As AI models and data centres expand across Europe, concerns are mounting about the environmental and economic impact of soaring electricity consumption.
The report, released by Photonics21 and authored by TEMATYS, warns that electricity use by AI is outpacing the capacity of existing power grids. According to the International Energy Agency, global data centres consumed 415 TWh of electricity in 2024. TEMATYS projects this figure could more than double by 2030 if current growth rates continue, largely because of increased AI workloads.
Such levels of energy consumption risk undermining Europe's efforts to meet climate commitments. The study finds that current silicon-based semiconductor technologies are unable to keep up with the increasing need for computational power without heavy energy and environmental costs.
Photonics potential...Photonics, the use of light to transmit and process information, is presented in the study as a critical complement to existing chip technology. Integrating photonic elements into data centres and chip architectures-using methods such as co-packaged optics-could significantly cut energy use and emissions associated with AI computing.
The report highlights that while photonics will not replace CPUs or GPUs, it can alleviate the pressure on them, reducing the carbon and cost implications of AI expansion. It also states that the right policy and investment choices in the coming years will determine whether Europe can maintain control over its AI hardware supply chain and uphold its environmental objectives.
"Photonics can provide the infrastructure that will determine whether AI becomes cleaner and more competitive or simply costlier and dirtier. Europe has the research base to lead; what it lacks is coordinated investment and industrial scale," said Sébastien Bigo, Nokia Bell Labs Fellow and Photonics21 Work Group Leader for Digital Infrastructure.
The growth of artificial intelligence requires connecting thousands of processors that continuously exchange information. This communication consumes energy and contributes to the heat that data centers must dissipate. One approach to reducing this burden is to bring light-based transmission closer to the chips themselves. Known as photonics, this field has the potential to make networks more efficient and—depending on the cooling method used—can also lower the demand for water.
“We are reaching the end of the copper era,” states Chris Sharp, Chief Technology Officer at Digital Realty, in the original text. This remark refers to the possibility of replacing some of the connections currently used to transport data.
This does not mean eliminating metal from data centers entirely; copper remains essential for electrical infrastructure and other critical systems.
The focus is on specific links between equipment and processors. As computational capacity grows, transporting information quickly and efficiently becomes just as important as performing the actual calculations.
A powerful processor offers little advantage if it has to wait for data to arrive from other components.
Photonics uses light to transport information. It involves the generation, control, and detection of light. Within networks, information can travel as optical signals rather than relying solely on electrical connections.
Fiber optics are already used for long-distance communications and many internal connections within data centers. The next step is to bring optical components closer to electronic circuits—even integrating them into the same package.
Nvidia describes this type of integration in its networking technologies, where optical transmitters and receivers are placed near the chips in switches—the equipment responsible for routing data.
The goal is to shorten electrical paths and reduce the energy consumption associated with communication. However, the gains reported for these specific components do not translate into an equivalent reduction in the total energy consumption of an entire data center. Optical transmission can reduce losses and the energy required to move large volumes of information. It can also decrease some of the heat that a facility needs to remove.
However, using light does not make a system free from electrical consumption. Lasers, control circuits, and converters still require power, while processors continue to generate heat.
The relationship with water stems from cooling requirements. The U.S. Department of Energy explains that reducing dissipated heat can lower water usage in evaporative cooling towers.
Thus, photonics can indirectly contribute to water conservation in these facilities. The actual outcome varies depending on the specific design, climate, and equipment used.
Integrating optics and electronics necessitates new manufacturing approaches. This transition brings together industrial processes that must function in tandem; it is not as simple as swapping out a cable—optical components require precise alignment, testing, and assembly.
The CORNERSTONE platform, based at the University of Southampton, provides silicon photonics prototyping services, bridging the gap between research and manufacturing.
According to experts cited in the original text, the expertise gained within the semiconductor industry can help scale up production. Furthermore, certain processes allow for the reuse of equipment from previous generations.
Even so, cost reduction requires the coordination of suppliers, manufacturing, packaging, and maintenance. Technical efficiency must be matched by economic viability.
Light does not eliminate thermal challenges. Optical components remain surrounded by equipment that generates heat; because their performance can be temperature-sensitive, environmental control remains essential.
Such facilities also require specialized handling. Optical fibers have specific bend radius limits and necessitate distinct procedures for handling, connecting, and maintenance.
Another frontier involves minimizing the frequent conversions between optical and electrical signals. Architectures capable of keeping data within the optical domain for more stages could significantly enhance efficiency.
Photonics uses light (photons) instead of electricity (electrons) to transmit and process information, which can dramatically lower energy consumption and cooling needs in artificial intelligence data centers.
Why photonics reduces energy consumption:
• Zero resistance losses: Electrons moving through copper wires face electrical resistance that converts energy into waste heat. Photons have no charge and travel through optical waveguides with almost no loss.
• High-speed interconnects: Optical connections and co-packaged optics (placing photonic circuits next to GPUs on the same silicon) reduce the power needed to transfer data between chips by 50% to 80%.
• Optical matrix nultiplications: Neural networks rely heavily on matrix and vector operations. Photonic chips can perform these mathematical calculations using light in parallel, yielding up to two orders of magnitude lower carbon emissions and energy use compared to traditional electronic processors.
• Wavelength-division multiplexing: A single optical connection can carry multiple streams of data at different light frequencies, replacing dozens of power-hungry electronic connections.
How this lowers water consumption:
• Less waste heat: Because light-based operations generate significantly less thermal dissipation than electrical circuits, the chips run much cooler.
• Reduced cooling demands: Traditional AI data centers require massive amounts of water for evaporation-based cooling systems and chillers to combat the intense heat of GPUs. By cutting heat at the hardware level, data centers can scale down or eliminate water-intensive cooling infrastructure.
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