Colt and Ciena completed what the pair claim to be one of the fastest quantum-safe data transmissions ever, having run an 800 Gb/s link across the Atlantic.

The trial employed a trans-Atlantic route stretching from New York and London, with Ciena’s coherent WaveLogic 6 Extreme (WL6e) technology used to provide high-capacity secure connectivity and data encryption.

While quantum computing creeps ever closer – particularly with Google’s mould-breaking 2029 Q-day prediction – enterprises are increasingly concerned about the safety of their data in transmission, fearful of the encryption-unlocking powers quantum computers herald. Even the rise of "harvest now, decrypt later" has seen threat actors scramble for data with the view of breaking encryptions once quantum systems proliferate.

The pair positioned the trial as evidence that quantum-safe transfers can become a reality, especially on some of the world’s busiest data corridors.

“As network demand surges, operators are raising the security bar to stay ahead of the threat posed by quantum computers,” Dino DiPerna, SVP for global research and development at Ciena, explained in a statement. “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.”

The tests come as 800G marks the next connectivity level network operators are working toward, usurping 400G – though that hasn’t stopped hyperscale level firms toying with 1.6 Tb/s (1.6T) speeds.

But the quantum-safe aspect is one Ciena has been looking into for some time.

The optics maker previously collaborated with the Spanish network infrastructure research hub REDIMadrid on end-to-end quantum secure data transports, with the pair integrating a quantum channel with existing dense wavelength division multiplexing (DWDM) signals over the same fiber.

For these latest tests, it’s found a partner in Colt that’s similarly aggressively working on quantum-safe networking.

The British-based firm previously teamed up with Nokia and Honeywell on applying quantum-safe networking using satellite communications, while also employing quantum key distribution (QKD) in optical transport field trials with Adva.

Colt COO Buddy Bayer said its latest trials “prove that quantum safe protection can be delivered at real-world scale.”

“Colt’s infrastructure combines global reach, sustained investment, and robust security, giving businesses, hyperscalers, and neoscalers the confidence to grow. At the same time, Ciena’s quantum safe solutions show how next-generation security can be embedded into high-speed networks, ensuring protection keeps pace with performance,” Bayer said. “Together, we’re helping customers protect critical data today while preparing for the quantum era, building future-ready networks that simply work, and are secure, scalable, and ready to power the AI economy.”