Quantum Networks

Quantum Key Distribution (QKD) is an emerging technology that uses the fundamental laws of quantum physics in order to ensure secure communication. Quantum networks enable secure distribution of quantum crypto keys among multiple users in a commercial network infrastructure.

What are the issues we are trying to address?

Our nation's business and defense require secure transmission of information over communication links. There is a continuing need to develop advanced technologies to safeguard data transmission and communications. QKD has been shown to be an effective cryptography key distribution mechanism when quantum computing becomes a reality, but it is still a developing technology. In order to make QKD practical, we need to improve its performance in terms of key generation speed, transmission distance, and lowering error rates. We need to develop measurement methodologies and metrics for the new system, and new protocols and standards for the new QKD infrastructure.

What are we doing to address these issues?

We have built an open system for research, testing, calibrations, and technology development in a real-world telecommunications environment. We are developing a testbed and measurement infrastructure for testing new photon sources and detectors, and new methods for transmitting quantum keys over standard telecom infrastructures.

Accomplishments and future outlook for Quantum Networks?

In 2000 the NIST Information Technology Laboratory (ITL), in collaboration with the NIST Physics Laboratory and with the support of DARPA, initiated a project to build the infrastructure for a high-speed Quantum Key Distribution (QKD) system using a free space link. By 2004 we demonstrated free space QKD over 730 meters at a key rate of 1 Mbit/s.
In 2005 ITL began to research QKD in fiber, and by 2006 we had developed a fiber channel QKD system with 4.14 Mbits/s key rates at over 1 km of fiber while maintaining a quantum bit error rate (QBER) as low as 3.4%. Also, by 2006 we demonstrated QKD transmission using telecom wavelengths for optimal distances, built a novel frequency up-conversion module with very low noise for optimal transmission and detection of photons, and demonstrated a three-user QKD network (one Alice and two Bobs), suitable for QKD local-area-networks (LANs). We will be extending the range to cover Metropolitan-area-networks (MANs).
For more information concerning this program, please contact project leader Dr. Xiao Tang (xiao.tang@nist.gov).
Keywords: quantum communication, cryptography & key distribution (QKD), BB84, free space optics, photon source/dectors.

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