March 13, 2024 By Reece Brown, Oak Ridge National Laboratory
Researchers at the Department of Energy's Oak Ridge National Laboratory have demonstrated that advanced quantum-based cybersecurity can be realized in a deployed fiber link.
Their results, published in CLEO 2023, validate an earlier proof-of-principle laboratory experiment by ORNL scientists in 2015.
The team transmitted a quantum signal for quantum key distribution––a secure approach to sharing a secret key––using a true local oscillator. A local oscillator quells the effects of noise scattered from other data transmitted in the same fiber-optic network, and the work demonstrated coexistence between the quantum and conventional data signals.
The signal traveled across ORNL's fiber-optic network encoded in continuous variables that described the properties of light particles, or photons, in amplitude and phase. Using continuous variables of photons for encoding allows an almost infinite number of settings for distributing randomness that can be used for cybersecurity and enables compatibility with existing classical communications systems.
The ORNL team's experiment not only broke new ground in information security but leveraged existing fiber-optic infrastructure, which would enable cheaper, easier adoption.