Researchers strengthen the digital infrastructure and connectivity of the Baltic Sea region

Researchers strengthen the digital infrastructure and connectivity of the Baltic Sea region. 15.04.2025. A new focus on digital resilience in the Baltic Sea What was once a forward-looking scientific investment has now become clear: waiting is not an option, action must be taken immediately. The laboratory provides an opportunity to develop and test cutting-edge monitoring technologies that help prevent disruptions to critical communication links and strengthen the region’s digital infrastructure’s resilience and security. The laboratory is led by Dr. Kaida Kaeval, Senior Researcher at TalTech’s Thomas Johann Seebeck Department of Electronics. Unlike typical academics, Kaeval has deep understanding of both scientific and commercial networks. Before joining TalTech, Kaeval worked for over a decade in mission-critical communications – initially at Televõrgu AS and later at Tele2 Estonia, where she led the development of the data backbone between the Baltics and Europe. She then developed optical spectrum services for international operators at ADVA in Germany. Kaeval’s ability to translate complex scientific concepts into the language of network engineers and operators – and vice versa – makes TalTech’s lab more than just an academic environment. It could become a central hub for digital resilience in the region. The Baltic Sea as the front line of digital geopolitics In the past year, sabotage activities targeting underwater electrical, communication, and gas infrastructures have increased in the Baltic Sea region. Kaeval emphasizes that passively waiting for the next disruption is not an option. “We need to be able to sense when something is changing, not react only when it’s too late.” “We need to be able to sense when something is changing, not react only when it’s too late.” This need is the basis for the development of TalTech’s Baltic Sea sensor network, which uses the free light fibers in existing communication cables to detect immediate environmental changes. The network is part of the European Commission-funded ICON (Intent and Context-Aware Optical Networks) project, aimed at developing proactive monitoring systems and strengthening critical infrastructure protection, even in the case of geopolitical crises. Kaeval explains that the Baltic Sea sensor network operates by leveraging existing optical cables and can detect vibrations, changes in tension, and temperature fluctuations along the cable. For example, the system can detect vibrations caused by an anchor or trawl dragging along the seafloor, kilometers away from the cables. By analyzing the strength and direction of the signal, it is possible to determine the trajectory of a potential threat. This is not just important for the internet – the same cables also carry critical control information, which directs the operation of electricity, gas, and water networks. If a cable is damaged, the entire infrastructure could be disrupted, not just data communication. According to Kaeval, the sensor network sends light pulses along the optical cable and monitors how they are reflected back. When unusual activity occurs around the cable – such as vibration, temperature change, or physical strain – the light behaves differently. Through these changes, the system can detect if and where something is happening. “Thanks to highly precise technology, it is possible to detect an issue before the cable is actually damaged, allowing for prompt intervention,” Kaeval said. For businesses, production downtime or data disruption can mean millions of euros in losses. The sensor network provides a way to prevent such risks. “Thanks to highly precise technology, it is possible to detect an issue before the cable is actually damaged, allowing for prompt intervention.” Data without borders Another key area of the laboratory’s research focuses on developing optical spectrum services – a technology that could revolutionise the functioning of Europe’s data networks. This pertains to the lower layer of the network, known as the physical backbone or trunk network, where data is transferred solely by photons, or light particles. These backbone networks rely on wavelength division multiplexing technology. Simply put: by using different wavelengths or “colours” of light that the human eye cannot see, it becomes possible to transmit enormous amounts of data simultaneously over a single optical fibre. The commonly used wavelength range for this purpose is 1530–1570 nanometres. This range is divided into tens of smaller wavelengths, each capable of carrying data at speeds of up to 600–800 gigabits per second. These wavelengths function as a group between the sender and receiver, and thanks to effective amplification technologies, the length of these communication routes can extend from hundreds of kilometres to thousands. Currently, user data is converted into a light signal in the backbone networks before transmission, using opto-electro-optical conversion, and specific manufacturer devices, known as transceivers, are required for this process. When a light signal crosses, for example, a border between networks, it must be converted back to electrical and then back to optical, so it fits the technical requirements of the next network. This process is expensive, slow, and inefficient. “Spectrum service allows the light signal to move seamlessly through multiple network operator systems without needing to convert the signal in between. This way, we get faster, cheaper, and more efficient data transmission in long-range networks,” explained Kaeval. “Spectrum service allows the light signal to move seamlessly through multiple network operator systems without needing to convert the signal in between. This way, we get faster, cheaper, and more efficient data transmission in long-range networks.” For the light signal to travel seamlessly between networks, it must meet the technical requirements of the next network at every interconnection point. While expensive transceivers were previously used for this, TalTech is developing a smart device that can adjust and calibrate the signals in real-time. This eliminates disruptions and ensures that the signal does not interfere with other wavelengths or the network’s operation. The result is faster, more stable, and reliable data transmission, and more affordable service for the end user. Thus, aside from reliability, cost is also a crucial factor. Kaeval explains that in Estonia, customers currently pay more for connections than in many parts of Europe due to additional costs arising from our network’s geography and the risk of failures. The spectrum service helps significantly reduce these costs and keeps prices under control, even as data volumes grow. Communication is born from collaboration TalTech’s new optical communications and sensing laboratory collaborates with both Estonian and international network companies, including partners such as Telia, Tele2, CITIC Telecom, and Elering. These partners provide access to their unused or “dark” optical fibres and spectrum, which is highly valuable for testing, as commercial networks typically do not allow for such trials. Companies are also involved in piloting new technologies. In the future, the lab sees broader applications for sensor networks, for example, in the insurance sector or logistics, where uninterrupted data transmission is critical. In Estonia, the rapid collaboration is supported by a small and close-knit telecommunications market. “Our partners are willing to contribute because they see a common goal in the developments. In larger European countries, it is somewhat more difficult, as major operators often struggle to understand how participation in research or testing solutions might be beneficial to them,” explained Kaeval. “Our partners are willing to contribute because they see a common goal in the developments. In larger European countries, it is somewhat more difficult, as major operators often struggle to understand how participation in research or testing solutions might be beneficial to them.” One of the laboratory’s technical strengths is its ability to test new devices on a 500 km long, older-type optical fibre – a type that is no longer produced, although it is still used in networks. Kaeval and the lab’s work have far-reaching impacts beyond Estonia. TalTech’s partners already include network specialists from Germany, Denmark, Poland, Finland, Ireland, and Spain – all searching for solutions to make European communication networks more secure, resilient, and flexible. TalTech’s new optical communications and sensing laboratory plays a crucial role in this context