Long Distance Quantum Data

Quantum networks secure data using a technique called Quantum Key Distribution (QKD), which exchanges encrypted key information using photons. It’s virtually impossible to hack because any attempt at intercepting the data will disrupt the quantum state of the light particles, which can be detected by the communicating parties. However, the photons can only travel short distances through optical fibers before they scatter, causing data rates to drop sharply.

Toshiba recently announced that they have developed a new protocol called Twin-Field QKD that will enable quantum data to be transmitted over distances of 500 kilometers at rates of up to 100 bits per second. Until now, the longest demonstrated range of QKD was about 400 kilometers at 1.15 bits per hour. Although conventional systems can be chained together to increase the total transmission distance, this requires intermediate secure stations in guarded locations along the entire route. The new protocol would allow sites to be connected at much greater distances and make it possible for organizations to network at a national or even international level.