Scientists are working to send quantum information through existing fiber networks. This shift could save billions in infrastructure costs and speed up the arrival of quantum-powered technologies.

Unlike regular data, quantum communication sends information through single photons. These photons hold fragile quantum states that are easy to disturb. That makes sharing fiber lines with classical Internet traffic a serious technical challenge.

Classical signals, especially those powered by lasers, flood the fiber with light. This generates a kind of noise called inelastic scattering. One type, known as spontaneous Raman scattering, floods the line with stray photons that can drown out the quantum signals.