Korean Researchers Pioneer Quantum Key Distribution Breakthrough

Researchers in South Korea have made significant advancements in the field of quantum key distribution (QKD) by establishing a measurement protection (MP) theory, allowing for stable quantum communication without requiring constant calibration of quantum states. This groundbreaking research, conducted by the Electronics and Telecommunications Research Institute (ETRI) in collaboration with the Korea Advanced Institute of Science and Technology (KAIST), was published in the IEEE Journal on Selected Areas in Communications.

The newly developed technology addresses a critical challenge in quantum communication: maintaining stable connections in dynamic environments such as satellites, ships, and drones. Traditional QKD protocols have struggled in these contexts due to the influence of weather and environmental changes, which can destabilize communication. With this latest innovation, researchers have demonstrated the potential for reliable quantum information exchange while in motion.

In their research, the team led by Professor Bae Jun-woo at KAIST implemented a long-distance free-space transmission setup capable of simulating challenging free-space conditions. They successfully verified quantum transmission over a distance of 10 meters, achieving up to 30 dB loss while introducing various polarization noises. The experiments confirmed that the MP-based QKD system could increase the maximum allowable Quantum Bit Error Rate (QBER) by as much as 20.7% compared to existing systems. This means that stable key distribution is feasible without additional measurement correction, as long as the error rate remains below this threshold.

The implications of this research extend to several applications, including secure communication between satellites and ground stations, drone networks, and maritime operations. By ensuring stable key generation in various noisy environments, this breakthrough paves the way for more reliable quantum communication systems.

Additionally, ETRI researchers have addressed another significant challenge in QKD: the “Polarization-Dependent Loss” problem. This key issue affects the performance of integrated chip-based QKD systems, which are considered the next generation of quantum communication technologies. By demonstrating that performance degradation caused by polarization-dependent loss can be compensated with simple optical components, the researchers aim to facilitate the commercialization of compact and lightweight QKD equipment.

Youn Chun Ju, Assistant Vice President of ETRI’s Quantum Technology Research Division, emphasized the importance of this breakthrough, stating, “The implementation of QKD independent of channel status variations significantly enhances the flexibility of quantum cryptography.” The team plans to expand this technology to long-distance free-space links, laying the foundation for a global quantum network.

The findings from this research, which have been recognized for their potential impact on future quantum communication systems, represent a decisive turning point in achieving reliable quantum secure communications even in complex environments. As the field of quantum technology continues to evolve, these advancements are expected to play a crucial role in the development of secure communication infrastructures worldwide.

For further insights into the research, please refer to the original publication: Heasin Ko et al, “Secure Quantum Communication With the Preservation of Optimal Measurements,” in the IEEE Journal on Selected Areas in Communications (2025).