Photon Demultiplexing Using Spatial Routing
Abstract
Spatial sectioning of the far-field noncollinear field from spontaneous parametric down-conversion (SPDC) is a promising approach for multiparty quantum communication. Although demonstrations with six pairs of users have been reported, the fundamental limits remain unknown. These include the maximum number of channels, the required degree of channel optimization, and the dependence on input parameters. In this paper, we provide a practical framework that answers these questions by connecting input parameters and invoking a design theorem. For a representative configuration, we realize 12 user-pair channels with routing consistency exceeding $0.9999$ at a 12% reduction in photon flux. We further show that sectioning improves the accidental-coincidence budget linearly with the number of channels N, allowing the aggregate key rate to scale with the user count. These results provide a design strategy for spatial-division multiplexing of entangled photons analogous to the channel-spacing standards used in wavelength-division networks.
Related
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- Spatial symmetry in few-photon interference and quantum metrology
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BibTeX
@misc{kuniyil2026photon,
title = {{Photon Demultiplexing Using Spatial Routing}},
author = {Hashir Kuniyil and Asad Ali and Saif Al-Kuwari},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.19933},
eprint = {2610.19933},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.19933},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Photon Demultiplexing Using Spatial Routing
AU - Hashir Kuniyil
AU - Asad Ali
AU - Saif Al-Kuwari
PY - 2026
DA - 2026/10/14
PB - arXiv
DO - 10.48550/arxiv.2610.19933
UR - https://arxiv.org/abs/2610.19933
AB - Spatial sectioning of the far-field noncollinear field from spontaneous parametric down-conversion (SPDC) is a promising approach for multiparty quantum communication. Although demonstrations with six pairs of users have been reported, the fundamental limits remain unknown. These include the maximum number of channels, the required degree of channel optimization, and the dependence on input parameters. In this paper, we provide a practical framework that answers these questions by connecting input parameters and invoking a design theorem. For a representative configuration, we realize 12 user-pair channels with routing consistency exceeding $0.9999$ at a 12% reduction in photon flux. We further show that sectioning improves the accidental-coincidence budget linearly with the number of channels N, allowing the aggregate key rate to scale with the user count. These results provide a design strategy for spatial-division multiplexing of entangled photons analogous to the channel-spacing standards used in wavelength-division networks.
ER -