Demonstrating Security of Fiber Networks with Quantum Resources

PhoQuS team members Chaohan Cui, Jack Postlewaite, and Saikat Guha take part in a new demonstration of quantum-enabled security of fiber networks at QLAB.

The team, together with collaborators from the University of Texas at Austin, RTX BBN Technologies, and UC San Diego, developed a quantum-enhanced threat detection scheme that confines all quantum interventions to the physical layer, keeping it compatible with existing network infrastructure. The approach combines bright squeezed light with classical optical signals and continuous CUSUM statistical analysis to detect eavesdropping beyond classical detection limits. In field trials over a 5+ kilometer fiber loop connecting QLab to the University of Maryland campus, the system detected a simulated 10% optical tapping event without disrupting data throughput, running stably for 20 hours.

Read more at QLab News and see the paper on arXiv:2607.10799.