Researchers at Karlsruhe Institute of Technology (KIT) and École Polytechnique Fédérale de Lausanne (EPFL) are presenting a novel component that enables very fast, economical, and reliable data transmission thanks to a advanced manufacturing technology. Their new electro-optical modulator transmits data efficiently through fiber-optic cables and can be manufactured inexpensively in large quantities on standard semiconductor wafers. This is important, as AI applications and growing data traffic are pushing data centers and fiber-optic networks to their performing limits. The researchers present their findings in Nature Communications. (DOI: 10.1038/s41467-026-69769-3)
Similar to modern computer chips, the modulator can be manufactured using established semiconductor processes. The researchers combine lithium tantalate — a material that guides light particularly well and serves as the heart of the modulator — with a proven chip manufacturing technique from microelectronics. To date, these two technologies have never been used together. For the first time now, they enable reliable mass production.
Mass-Production Techniques Proven Millions of Times
Light modulators convert electrical signals into light pulses which already are the basis for high-speed internet and ideal for applications with massive data streams, such as artificial intelligence training. Yet, the manufacturing process is new: “The key advance lies in the copper electrodes and the way we manufacture them,” says Professor Christian Koos, Head of KIT’s Institute of Photonics and Quantum Electronics (IPQ). This is because copper conducts signals better than the gold used so far. At the same time, copper enables very smooth surfaces, which makes the component more efficient because less energy is lost. The copper electrodes can be manufactured using a process that has already been tested millions of times in the production of electronic computer chips. Unlike earlier methods, this results in an almost mirror-smooth surface that allows the optical microchips to be easily connected to electronic chips. This not only makes modulators easier to manufacture, but also allows them to be integrated better into existing electronic systems.
Highest Data Rates with Stable Operation
Tests conducted by the KIT team show: “The modulator enables very high data rates and, above all, runs stably without us having to constantly correct the settings,” says Alexander Kotz, also from IPQ. This is a major advance, as constant readjustment during continuous operation is costly, complicates transmission systems, and consumes energy Considering the millions of such components used in data centers and AI clusters, this is a particularly critical point.
The modulator reaches data rates of over 400 gigabits per second, which corresponds to the simultaneous transmission of around 80,000 HD streams (at 5 megabits per second per stream) or of 8 complete HD movies. “We are working at the limits of what is technically possible today. With more powerful control electronics, we could even increase the data rates,” Kotz adds. “Fast, economical, reliable, and manufacturable on an industrial scale — this combination makes the technology attractive, especially for data centers and AI clusters that are already suffering from bottlenecks in data exchange between processors,” emphasizes Koos
Original Publication
Cai, J., Kotz, A., Larocque, H. et al. Heterogeneously integrated lithium tantalate-on-silicon nitride modulators for high-speed communications. Nat Commun (2026). 10.1038/s41467-026-69769-3
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