Experimental spatial-spectral allocation for quantum-classical coexistence over multicore fiber.

Area of Science:

• Quantum communication
• Optical networking
• Information security

Background:

• Classical optical networks are evolving towards higher capacity and integration.
• Quantum Key Distribution (QKD) offers unparalleled security but faces integration challenges with existing infrastructure.
• Co-transmitting QKD and classical signals in multicore fibers (MCF) is a promising but complex endeavor due to inter-core noise.

Purpose of the Study:

• To develop and experimentally validate a resource allocation framework for co-transmitting QKD and classical signals in MCF.
• To analyze and mitigate inter-core noise interference between quantum and classical channels.
• To enhance secure key rates in integrated quantum-classical optical networks.

Main Methods:

• Theoretical modeling of inter-core noise interference mechanisms in MCF.
• Development of a noise-aware spatial-spectral resource allocation scheme.
• Experimental validation using a Cartesian coordinate-based core allocation and adaptive wavelength assignment.

Main Results:

• Demonstrated superior noise suppression capabilities, achieving reductions of ⩾ 4.2 dB in noise photons.
• Achieved enhanced secure key rates, with improvements of ⩾ 10 kbps compared to benchmark approaches.
• Validated the universal compatibility of the core allocation hierarchy with arbitrary MCF configurations.

Conclusions:

• The proposed noise-aware resource allocation scheme is effective for co-existing QKD and classical signals in MCF.
• This framework provides a practical foundation for integrating QKD into existing fiber infrastructure.
• The work advances the realization of scalable and secure quantum-classical coexistence in optical networks.