Field test of wavelength-saving quantum key distribution network

Area of Science:

• Quantum Information Science
• Network Engineering
• Optical Communications

Background:

• Quantum Key Distribution (QKD) networks offer enhanced security but often require dedicated infrastructure.
• Efficient use of optical spectrum is crucial for practical network deployment.
• Existing QKD systems face challenges with scalability and integration into telecommunication networks.

Purpose of the Study:

• To propose and field-test a novel, wavelength-saving topology for Quantum Key Distribution (QKD) networks.
• To demonstrate the feasibility of a multi-node QKD network using passive optical components.
• To evaluate the performance impact of the proposed network topology on QKD systems.

Main Methods:

• Development of a wavelength-saving QKD network topology utilizing passive optical elements.
• Field testing of the QKD network over commercial telecom optical fiber at 20 MHz.
• Characterization of insertion loss and crosstalk effects on point-to-point QKD links within the network.

Main Results:

• Successful implementation of a five-node QKD network using only two wavelengths.
• Demonstration of simultaneous secure key sharing between any two nodes in the network.
• Quantification of insertion loss and crosstalk impacts on the QKD system performance.

Conclusions:

• The proposed wavelength-saving QKD network topology is effective for multi-node secure key distribution.
• Passive optical elements enable a scalable and cost-efficient QKD network infrastructure.
• The network demonstrates compatibility with existing telecom fiber, paving the way for practical QKD deployment.