Researchers at the National Institute of Standards and Technology have completed a successful test of quantum networking over existing infrastructure. The team sent entangled photons across 38 miles of standard fiber-optic cable strung between utility poles from the NIST campus to the University of Maryland.
Quantum networking relies on the state of entangled particles, which are highly sensitive to environmental interference. While typical internet traffic moves through cables without issue, quantum information is easily corrupted by temperature shifts, vibrations, and wind. The team faced a noisy, real-world environment instead of a controlled laboratory setting.
To keep the data stable, the physicists used a reference laser signal to measure how much the environment twisted the path of the photons. This method allowed them to apply active corrections to the entangled particles. The team dedicated 7 percent of the operation time to this stabilization process, which kept the remaining 93 percent of the link open for reliable data transmission.
This experiment shows that quantum protocols can function outside of ideal conditions. While current transmission rates of roughly 1,500 photons per second remain experimental, the result proves that existing aerial fiber networks can support quantum communication. Future work will focus on increasing transmission speeds and improving hardware efficiency to move closer to a functional quantum internet.