Capacity and SKR tradeoff in coexisting classical and CV-QKD metropolitan-reach optical links

TL;DR

This paper investigates how to optimize guardbands for coexistence of classical and quantum key distribution channels in metropolitan optical networks, demonstrating significant SKR improvements with minimal capacity loss.

Contribution

It introduces power-regime-dependent guardband optimization strategies for quantum-classical coexistence in DWDM systems, achieving enhanced SKR performance.

Findings

Quantum channel at band-edge with optimized guardbands improves SKR by 108%.

Guardband optimization reduces capacity loss to 3.4%.

Performance varies with power regime and channel placement.

Abstract

We demonstrate power-regime-dependent guardband optimization for quantum-classical coexistence in metropolitan DWDM. Quantum channel at band-edge with 100-150 GHz guardbands achieves 108% SKR improvement at -1.5 dBm/ch, incurring 3.4% capacity loss versus 6.8% for band-center.