Quantum Network for Secure Communication
Secure communication is of central importance for a connected society. The foundations for this are provided by quantum physics, enabling practical technologies such as quantum key distribution. With the new fiber optic test track at Karlsruhe Institute of Technology (KIT), inaugurated on Wednesday, January 22, 2025, researchers aim to transmit, test, and further develop these keys. Moreover, they plan to establish a quantum network that will, among other things, enable the interconnection of quantum computers. (Source: Karlsruhe Institute of Technology – Press Release)
Using the new fiber optic test track, researchers leverage cutting-edge technologies such as highly coherent lasers to generate and transmit quantum keys. These keys are essential for secure communication, as they are based on physical laws rather than the mathematical assumptions of conventional keys, which could be compromised by future quantum computers.
At 20 kilometers in length, the quantum-optical transmission line connects specialized laboratories equipped with advanced lasers and cryostats at KIT’s South Campus and North Campus. The light-conducting core of the fiber optic cable has a diameter of just 9 micrometers, compared to approximately 60 micrometers for a human hair.
A Crucial Platform for Quantum Research
“The topic of quantum communication is of great strategic importance for KIT. I am delighted that KIT is providing researchers with this important infrastructure through the established test track to explore the possibilities of quantum physics,” said Professor Oliver Kraft, Vice President for Research at KIT. “With this, we are making a significant contribution to advancing research and development in quantum network technologies and transitioning them to practical applications.”
“With the fiber optic test track, we now have a platform to further develop quantum key distribution, conduct fundamental characterizations, and integrate it into classical communication,” said Professor David Hunger, project leader from KIT’s Institute of Physics. Building on this, the scientists are developing novel transmission protocols for the keys. “With new methods, we aim to make quantum cryptography more efficient and practical. For example, we are collaborating with KEEQuant, a startup specializing in quantum-secure communication,” Hunger added. “Using specialized materials, we aim to generate highly pure quantum light—individual photons—and thereby increase transmission rates.”
Establishing a Quantum Network
In addition, researchers are constructing a quantum network step by step to explore the future quantum internet. Their focus is on two key steps: first, the storage of quantum information in specialized quantum memories, and second, the quantum entanglement of these memories. This approach makes it possible to realize quantum repeaters, enabling the transmission of quantum information over long distances. Since entanglement is a fundamental element of quantum computers, these devices can be interconnected in a quantum internet via the optical transmission of entanglement.
Test Track as Part of the Excellence Cluster Initiative Chem4Quant
The project is a central infrastructure of the excellence cluster initiative “Chem4Quant,” where researchers from KIT, the University of Ulm, and the University of Stuttgart focus on building material structures for future quantum technologies and exploring a new subfield of quantum technologies—molecular quantum systems. Furthermore, the project plays a critical role in research on quantum repeaters within the collaborative project Quantenrepeater.Net (QR.N), funded by the Federal Ministry of Education and Research, and contributes to the QuantumBW Innovation Campus.
KIT/S. Fodi, 22.01.2025
Note: The article has been translated from German to English. It is based on a press release from KIT.
The original press release can be found at:
Quantennetzwerk für eine sichere Kommunikation (only in german)
Localization in Helmholtz Information:
Helmholtz Information, Program 3: Materials Systems Engineering, Topic 2: Optics & Photonics: Materials, Devices, and Systems
Contact:
Prof. Dr. David Hunger
Physikalisches Institut (PHI)
Karlsruhe Institute of Technology (KIT)
Phone: +49 721 608-43510
E-Mail: david.hunger@kit.edu
Contact for this press release:
Dr. Sabine Fodi
Press Officer
Karlsruhe Institute of Technology (KIT)
Phone: +49 721 608-41154
E-Mail: sabine.fodi@kit.edu
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