Solar-Blind Free-Space QKD Using Large-Core Fibers for Alignment-Tolerant Link Operation

Autor(en)

Florian Honz, Winfried Boxleitner, Michael Hentschel, Philip Walther, Hannes Hübel, Bernhard Schrenk

Abstrakt

While fiber-optic quantum key distribution (QKD) systems have reached a technological maturity that permits field deployments, the complexity of free-space optical (FSO) QKD systems introduced to ensure minimal coupling loss over air hinders the use of QKD in fiber-scarce environments. As a response to this challenge, we present a simplified approach that leverages large-core fibers at the receiving air interface of short-range terrestrial FSO links. We show that the increased sensitivity to solar irradiance, as it arises from the adoption of alignment-tolerant multi-mode fibers, can be effectively mitigated through a spectral E-band allocation of the QKD channel. We accomplish a secure-key rate of 869 b/s/detector for a 63-m long outdoor free-space link during day-light operation at 42.9 klux, despite employing a 25-μm core fiber at Bob's QKD receiver. We further demonstrate the co-existence of a classical data stream over the solar-blind FSO QKD link.

Organisation(en)

Quantenoptik, Quantennanophysik und Quanteninformation

Externe Organisation(en)

Austrian Institute of Technology

Journal

Journal of Lightwave Technology

Band

43

Seiten

7155-7162

Anzahl der Seiten

8

ISSN

0733-8724

DOI

https://doi.org/10.1109/JLT.2025.3575204

Publikationsdatum

08-2025

Peer-reviewed

Ja

ÖFOS 2012

103025 Quantenmechanik, 103021 Optik

Schlagwörter

ASJC Scopus Sachgebiete

Atomic and Molecular Physics, and Optics

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/16d4da5a-6a10-458f-bbb1-03acba216bb4