Colt Technology Services and Ciena announced the successful completion of what the companies describe as the fastest quantum-safe data transmission demonstrated across a transatlantic route. The trial secured live traffic between New York and London over 6,900 km (4,287 miles) of Colt’s terrestrial and subsea infrastructure using Ciena’s WaveLogic 6 Extreme (WL6e) optical platform, while delivering an 800GbE service rate. The demonstration highlights the growing industry focus on protecting data against future quantum computing threats while maintaining the high-capacity connectivity required by AI workloads and large-scale data center operations.
The trial addressed concerns around “harvest now, decrypt later” attacks, in which adversaries collect encrypted data today with the intention of decrypting it once sufficiently powerful quantum computers become available. Ciena’s WL6e platform employed NIST-compliant post-quantum cryptography (PQC) algorithms integrated with its 1.6 Tbps coherent optical technology. According to the companies, the test validated the ability to combine quantum-safe protection with ultra-high-capacity optical transport over one of the world’s most heavily utilized international data corridors.
Colt said the results build on a series of quantum-safe networking initiatives across its terrestrial and subsea infrastructure. The carrier now offers multiple quantum-resilient security approaches, including PQC, Quantum Key Distribution (QKD), Symmetric Key Infrastructure (SKI), and hybrid architectures. The companies also noted that the trial demonstrated optical stability and performance characteristics suitable for emerging AI traffic requirements, where secure movement of massive data sets between geographically distributed data centers is becoming increasingly important.
“Operators are raising the security bar to stay ahead of the threat posed by quantum computers,” said Dino DiPerna, Senior Vice President of Global Research and Development at Ciena. “This Colt-Ciena trial shows how post-quantum cryptography and proven high-performance optical encryption can play an important role in protecting high-speed services over real-world long-haul and submarine networks, helping secure critical in-flight data across any distance.”
• 800GbE encrypted service transmitted between New York and London
• Route spanned 6,900 km (4,287 miles) across Colt’s terrestrial and subsea infrastructure
• Secured using Ciena’s WaveLogic 6 Extreme (WL6e) platform with post-quantum cryptography
• Demonstrated quantum-safe protection against future “harvest now, decrypt later” threats
• Validated performance over one of the world’s busiest transatlantic data routes
• Target use cases include hyperscalers, financial services, healthcare, government, and defense organizations
• Supports growing AI infrastructure requirements for secure, high-capacity inter-data-center connectivity
🌐 Analysis: The announcement extends a multi-year collaboration between Colt and Ciena focused on pushing the limits of high-capacity transatlantic optical networking. In November 2024, the companies announced the industry’s first 1.2 Tbps wavelength transmission across the Atlantic, and in 2025 they unveiled a new terabit-scale network deployment supporting major hyperscaler customers. This latest milestone shifts the focus from pure transport capacity to the intersection of bandwidth and security as operators prepare for the post-quantum era.
🌐 The broader optical networking industry is rapidly integrating post-quantum cryptography into transport platforms. Competitors including Nokia, Adtran, BT, Verizon, Deutsche Telekom, and several national research networks have conducted PQC and QKD trials, but most have focused on security validation rather than combining quantum-safe protection with emerging 800GbE transport services. As AI infrastructure drives demand for higher-capacity interconnects, operators increasingly view quantum-safe networking as a strategic requirement rather than a future enhancement.
