Asymmetric mode-pairing quantum key distribution

Abstract

Mode-pairing quantum key distribution (MP-QKD) can surpass the repeaterless rate-transmittance bound (Pirandola-Laurenza-Ottaviani-Banchi bound) without requiring global phase locking, exhibiting remarkable flexibility. However, MP-QKD necessitates equal communication distances in two channels, which is a challenging requirement in practical applications. To address this limitation, we extend the original MP-QKD to asymmetric cases. Our decoy-state estimation confirms that asymmetric channel transmittances and asymmetric intensities do not compromise the security of the protocol. We focus on the pulse-intensity relationship, a key factor for optimizing the performance of asymmetric MP-QKD. Unlike previous asymmetric protocols, the intensities of different bases in asymmetric MP-QKD cannot be decoupled. We introduce an optimal-pulse-intensity method, adaptable to various scenarios, to enhance key rates by calculating ideal pulse intensities. Simulation results in various representative scenarios indicate that our method effectively reduces the impact of asymmetric channel distances on MP-QKD performance, enhancing its practical applicability.

References in corpus (8)

• Device-independent security of quantum cryptography against collective attacks
• Measurement device independent quantum key distribution over 404 km optical fibre
• Device-independent quantum key distribution secure against collective attacks
• Experimental quantum key distribution beyond the repeaterless secret key capacity
• Measurement-device-independent quantum key distribution over 200 km
• Improved key rate bounds for practical decoy-state quantum key distribution systems
• Noisy pre-processing facilitating a photonic realisation of device-independent quantum key distribution
• Asymmetric sending or not-sending twin-field quantum key distribution in practice