Characterising higher-order phase correlations in gain-switched laser sources with application to quantum key distribution

Fuente: arXiv
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Hauptverfasser: Marcomini, Alessandro, Currás-Lorenzo, Guillermo, Rusca, Davide, Valle, Angel, Tamaki, Kiyoshi, Curty, Marcos
Format: Preprint
Veröffentlicht: 2024
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author Marcomini, Alessandro
Currás-Lorenzo, Guillermo
Rusca, Davide
Valle, Angel
Tamaki, Kiyoshi
Curty, Marcos
author_facet Marcomini, Alessandro
Currás-Lorenzo, Guillermo
Rusca, Davide
Valle, Angel
Tamaki, Kiyoshi
Curty, Marcos
contents Multi-photon emissions in laser sources represent a serious threat for the security of quantum key distribution (QKD). While the decoy-state technique allows to solve this problem, it requires uniform phase randomisation of the emitted pulses. However, gain-switched lasers operating at high repetition rates do not fully satisfy this requirement, as residual photons in the laser cavity introduce correlations between the phases of consecutive pulses. Here, we introduce experimental schemes to characterise the phase probability distribution of the emitted pulses, and demonstrate that an optimisation task over interferometric measures suffices in determining the impact of arbitrary order correlations, which ultimately establishes the security level of the implementation according to recent security proofs. We expect that our findings may find usages beyond QKD as well.
format Preprint
id arxiv_https___arxiv_org_abs_2412_03738
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Characterising higher-order phase correlations in gain-switched laser sources with application to quantum key distribution
Marcomini, Alessandro
Currás-Lorenzo, Guillermo
Rusca, Davide
Valle, Angel
Tamaki, Kiyoshi
Curty, Marcos
Quantum Physics
Multi-photon emissions in laser sources represent a serious threat for the security of quantum key distribution (QKD). While the decoy-state technique allows to solve this problem, it requires uniform phase randomisation of the emitted pulses. However, gain-switched lasers operating at high repetition rates do not fully satisfy this requirement, as residual photons in the laser cavity introduce correlations between the phases of consecutive pulses. Here, we introduce experimental schemes to characterise the phase probability distribution of the emitted pulses, and demonstrate that an optimisation task over interferometric measures suffices in determining the impact of arbitrary order correlations, which ultimately establishes the security level of the implementation according to recent security proofs. We expect that our findings may find usages beyond QKD as well.
title Characterising higher-order phase correlations in gain-switched laser sources with application to quantum key distribution
topic Quantum Physics
url https://arxiv.org/abs/2412.03738