Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Quantum Information and Measurement (QIM)

A Scalable Multi-User QKD Hub for Entanglement-Based Phase-Time Coding

Lucas Bialowons, Erik Fitzke, Maximilian Tippmann, Oleg Nikiforov, Thomas Walther

Published Jan 1, 2021• 2 citations
Publisher

Abstract

Simultaneous pairwise quantum key distribution between four parties was demonstrated by implementing an entanglement-based phase-time coding protocol with a type-0 SPDC photon source. The star-shaped network is scalable to dozens of users.
DOI
10.1364/qim.2021.m2c.4

Related papers

Scalable Network for Simultaneous Pairwise Quantum Key Distribution via Entanglement-Based Time-Bin Coding

Erik Fitzke, Lucas Bialowons, Till Dolejsky +5 more

A star-shaped, robust and scalable optical fiber network for simultaneous time-bin QKD is experimentally demonstrated with four participants including a field test and more than 100 km of fiber between users as well as full clock recovery.

arXiv:2110.13795•PRX Quantum•May 24, 2022•73 citations

An Entanglement-Based QKD System for Scalable Robust Multi-User Networks

Erik Fitzke, Till Dolejsky, Maximilian Tippmann +5 more

We present entanglement-based quantum key distribution in a star-shaped network with time-bin coding. We demonstrate key exchange under typical operation conditions for metropolitan-scale networks. Without much efforts, it is scalable to more than 100 users.

Conference on Lasers and Electro-Optics•Jan 1, 2022•0 citations

A Scalable Entanglement-Based Distributed Multi-User QKD System for Networks

Jakob Kaltwasser, Maximilian Tippmann, Florian Niederschuh +5 more

We report on the progress of our time-bin coding quantum key distribution network. We demonstrate its flexible operation, detector time multiplexing to reduce the number of detectors, and a key exchange with spatially separated parties.

•Jan 1, 2024•0 citations

An entanglement-based scalable city-wide distributed QKD network

Jakob Kaltwasser, Maximilian Tippmann, Maximilian Mengler +1 more

We demonstrate operation of our BBM92 quantum key distribution network with four spatially separated parties connected via field-deployed telecommunication fibers and show first results of a photonic chip designed to replace the source.

•Jan 1, 2025•0 citations

A scalable network for simultaneous pairwise quantum key distribution via entanglement-based time-bin coding

Lucas Bialowons, Erik Fitzke, Maximilian Tippmann +4 more

We present simultaneous quantum key distribution (QKD) between any two pairs of participants in a 4-party star-shaped optical fiber network without a trusted node. Our QKD system is the first to extend an entanglement-based time-bin coding protocol to multiple pairs of participants. We demonstrate key exchange over distances of more than 75 km and show that our network can be readily extended to at least 34 participants by using wavelength-division multiplexing in the optical C-band and with small modifications up to 102 participants. Our scheme is compatible to multiplexing approaches that were implemented earlier with polarization-based QKD and can thereby be extended to a fully connected network. In contrast to polarization-based QKD, the all-fiber system we present is insensitive to polarization instabilities in the fiber link. This enables key distribution networks with low quantum bit error rates and stable secure key rates using deployed fibers even under challenging environmental conditions.

•Oct 26, 2021•0 citations

Flexible reconfigurable entanglement-based quantum key distribution network

Till Dolejsky, Erik Fitzke, Lucas Bialowons +3 more

Abstract Recently, we implemented a basic star-shaped entanglement-based quantum key distribution network without trusted nodes. It enables simultaneous pairwise exchange of quantum keys between multiple users. In this paper, we demonstrate its flexibility by focusing on several aspects. We show continuous system operation over a partially deployed 100 km fiber link for multiple days as well as dynamic reconfiguration of the communication partners. The photon pair source enables type-II or type-0 photon pair generation by SPDC as well as various demultiplexing strategies and repetition rates.

The European Physical Journal Special Topics•Sep 12, 2023•5 citations
We present simultaneous quantum key distribution (QKD) between any two pairs of participants in a 4-party star-shaped optical fiber network without a trusted node. Our QKD system is the first to extend an entanglement-based time-bin coding protocol to multiple pairs of participants. We demonstrate key exchange over distances of more than 75 km and show that our network can be readily extended to at least 34 participants by using wavelength-division multiplexing in the optical C-band and with small modifications up to 102 participants. Our scheme is compatible to multiplexing approaches that were implemented earlier with polarization-based QKD and can thereby be extended to a fully connected network. In contrast to polarization-based QKD, the all-fiber system we present is insensitive to polarization instabilities in the fiber link. This enables key distribution networks with low quantum bit error rates and stable secure key rates using deployed fibers even under challenging environmental conditions.
Abstract Recently, we implemented a basic star-shaped entanglement-based quantum key distribution network without trusted nodes. It enables simultaneous pairwise exchange of quantum keys between multiple users. In this paper, we demonstrate its flexibility by focusing on several aspects. We show continuous system operation over a partially deployed 100 km fiber link for multiple days as well as dynamic reconfiguration of the communication partners. The photon pair source enables type-II or type-0 photon pair generation by SPDC as well as various demultiplexing strategies and repetition rates.