PacketLight Networks and NEC Corporation have successfully demonstrated Quantum Key Distribution (QKD) over a 400G DWDM network. The joint demonstration, held at NEC’s laboratories in Japan, integrated NEC’s QKD system with PacketLight’s PL-4000M 600G Muxponder. The aim was to showcase how quantum communication technology can operate alongside a DWDM optical network.
The QKD transmission was carried over a separate dedicated fiber, running in parallel to the main 400G data link fiber. This dual-fiber configuration is designed to ensure the integrity and stability of quantum signals while maintaining full performance of data traffic over the DWDM infrastructure. Throughout the demonstration, system compatibility and network performance were validated, with the encrypted data link achieving 100% throughput and consistently low latency, as verified with a 100GbE tester.
This demonstration suggests a scalable and cost-effective method for layering quantum security onto operational environments. It illustrates that quantum technologies can be deployed in parallel to existing infrastructures without requiring extensive overhauls. This model supports secure key exchange in real-world applications while preserving network simplicity and cost-efficiency, potentially facilitating broader adoption of quantum-safe communications. NEC has maintained a research base for QKD systems in Japan and has worked on its advancement for over 20 years.
Read the full announcement here.
July 30, 2025
