SK Telecom sets distance record with quantum repeater

SK Telecom has announced it has developed and successfully tested a quantum repeater over a 112km pilot fiber network.

The repeater can dramatically extend the distance of quantum communication, and could pave the way for the application of quantum cryptography to commercial LTE networks.

Quantum cryptography is the most secure form of communications equipment known that cannot be broken with any existing hacking technology. But the previous maximum transmission distance of 80km has been viewed as the largest obstacle to the commercialization of the technology.

SK Telecom said its new Trusted Repeater can dramatically extend the distance of quantum key distribution (QKD), and has set a new QKD distance record of 112km. For example, the company would be able to transmit quantum keys from Seoul to Busan, at a distance of 460km, by installing five repeaters.

The operator plans to work with global partners to apply quantum cryptography solutions including the repeater to commercial networks worldwide.

“SK Telecom has opened a new chapter in the field of quantum technologies by developing the Trusted Repeater, an enabler for long-distance quantum communication,” said Park Jin-hyo, senior vice president and head of network technology of SK Telecom’s R&D Center.

“SK Telecom will continue to focus on developing key quantum cryptography technologies and building a related ecosystem.”

The company has been developing quantum cryptography technologies since 2011 at its Quantum Tech lab. In February, SK Telecom entered an agreement with Nokia to cooperate on the quantum cryptography business, and jointly established the Quantum Alliance with Deutsche Telekom.