Improvement of entanglement generation rate in frequency-multiplexed quantum repeaters using cavity-enhanced SPDC source

Fuente: arXiv
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Main Authors: Komatsudaira, Ryoma, Horikiri, Tomoyuki
Format: Preprint
Published: 2026
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author Komatsudaira, Ryoma
Horikiri, Tomoyuki
author_facet Komatsudaira, Ryoma
Horikiri, Tomoyuki
contents High-rate entanglement generation is essential for the realization of practical quantum repeaters. To this end, frequency multiplexing of the photons employed is an effective approach. In particular, schemes using cavity-enhanced spontaneous parametric down-conversion (cSPDC) as a photon-pair source have been proposed. In this study, toward a theoretical performance evaluation of frequency-multiplexed quantum repeaters based on cSPDC, we derive an approximate expression for the quantum state of the frequency-multiplexed photons, where each frequency mode is treated as an independent two-mode squeezed vacuum (TMSV) state. Using this expression, we calculate the heralding probability and fidelity of entanglement generation for several cases in a single-photon interference scheme using frequency multiplexing with cSPDC. Our results demonstrate that by multiplexing approximately 100 modes, the heralding probability improves to approximately 98% for an elementary link distance $L_\mathrm{EL}=25 \mathrm{km}$, even in scenarios where the fidelity exceeds 0.9 across all modes. Furthermore, for $L_\mathrm{EL}=100 \mathrm{km}$, we show that the heralding probability, which was approximately 0.7% in the single-mode case, increases to about 38% under the condition that the fidelity remains 0.9 or higher. These analytical results demonstrate the effectiveness of employing cSPDC as a photon-pair source for quantum repeaters.
format Preprint
id arxiv_https___arxiv_org_abs_2604_00434
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Improvement of entanglement generation rate in frequency-multiplexed quantum repeaters using cavity-enhanced SPDC source
Komatsudaira, Ryoma
Horikiri, Tomoyuki
Quantum Physics
High-rate entanglement generation is essential for the realization of practical quantum repeaters. To this end, frequency multiplexing of the photons employed is an effective approach. In particular, schemes using cavity-enhanced spontaneous parametric down-conversion (cSPDC) as a photon-pair source have been proposed. In this study, toward a theoretical performance evaluation of frequency-multiplexed quantum repeaters based on cSPDC, we derive an approximate expression for the quantum state of the frequency-multiplexed photons, where each frequency mode is treated as an independent two-mode squeezed vacuum (TMSV) state. Using this expression, we calculate the heralding probability and fidelity of entanglement generation for several cases in a single-photon interference scheme using frequency multiplexing with cSPDC. Our results demonstrate that by multiplexing approximately 100 modes, the heralding probability improves to approximately 98% for an elementary link distance $L_\mathrm{EL}=25 \mathrm{km}$, even in scenarios where the fidelity exceeds 0.9 across all modes. Furthermore, for $L_\mathrm{EL}=100 \mathrm{km}$, we show that the heralding probability, which was approximately 0.7% in the single-mode case, increases to about 38% under the condition that the fidelity remains 0.9 or higher. These analytical results demonstrate the effectiveness of employing cSPDC as a photon-pair source for quantum repeaters.
title Improvement of entanglement generation rate in frequency-multiplexed quantum repeaters using cavity-enhanced SPDC source
topic Quantum Physics
url https://arxiv.org/abs/2604.00434