Northwestern University engineers have achieved a major breakthrough by successfully demonstrating quantum teleportation through fiber optic cables actively carrying Internet traffic, paving the way for practical quantum communications without requiring separate infrastructure.
The groundbreaking research, published in Optica, shows that quantum and classical signals can coexist in the same cables - something previously thought impossible due to interference concerns.
"Nobody thought this was possible," said Professor Prem Kumar, who led the research at Northwestern's McCormick School of Engineering. "This opens the door to next-generation networks where quantum and classical communications share existing fiber optic infrastructure."
The team accomplished this feat by carefully selecting specific light wavelengths where scattering effects are minimized and implementing specialized filtering systems to reduce noise from regular Internet traffic. This allowed the delicate quantum signals to traverse the busy cables without degradation.
Quantum teleportation works by using entangled photons - particles of light that remain connected regardless of distance. Rather than physically transmitting information, the quantum state of one particle instantly affects its entangled partner, enabling ultra-secure communication at light speed.
In their experiment, the researchers set up a 30-kilometer fiber optic cable with entangled photons at each end. They successfully transmitted both quantum information and high-speed Internet data simultaneously through the same cable while maintaining the integrity of the quantum teleportation process.
"This is the first demonstration of quantum teleportation coexisting with classical communications in fiber," said Jordan Thomas, lead author of the study. "It shows we can implement advanced quantum applications without building separate dedicated infrastructure."
The team plans to extend their experiments to longer distances and explore using multiple pairs of entangled photons. They also aim to test the system using real-world underground cables rather than laboratory setups.
This breakthrough brings practical quantum networks closer to reality by showing they can be built using existing telecommunications infrastructure - a critical step toward widespread deployment of ultra-secure quantum communications.
The research demonstrates that with proper wavelength selection and filtering, quantum and classical signals can successfully share the same fiber optic cables, making quantum networks considerably more feasible to implement at scale.