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Related papers: Integrating a QPSK Quantum Key Distribution Link

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We report the first real world implementation of a Quantum Key Distribution (QKD) system over a 43dB-loss transmission line in the Swisscom fibre optic network. The QKD system is capable of continuous and autonomous operation and uses the…

We present a 625 MHz clocked coherent one-way quantum key distribution (QKD) system which continuously distributes secret keys over an optical fibre link. To support high secret key rates, we implemented a fast hardware key distillation…

The incorporation of multiplexing techniques used in Microwave Photonics to Quantum Key Distribution (QKD) systems bring important advantages enabling the simultaneous and parallel delivery of multiple keys between a central station and…

Quantum Key Distribution (QKD) is a leading technology for enabling information-theoretic secure communication, with protocols such as BB84 and its variants already deployed in practical field implementations. As QKD evolves from…

Free-space ground-to-ground links will be an integral part of future quantum communication networks. The implementation of free-space and fiber links in daylight inter-modal configurations are however still hard to achieve, due to the…

Security proofs of quantum key distribution (QKD) systems usually assume that the users have access to source of perfect randomness. State-of-the-art QKD systems run at frequencies in the GHz range, requiring a sustained GHz rate of…

Quantum Physics · Physics 2015-04-30 A. Martin , B. Sanguinetti , C. C. W. Lim , R. Houlmann , H. Zbinden

We present a design for a quantum key distribution(QKD) system in a Sagnac loop configuration, employing a novel phase modulation scheme based on frequency shift, and demonstrate stable BB84 QKD operation with high interference visibility…

Quantum Physics · Physics 2009-11-13 Bing Qi , Lei-Lei Huang , Hoi-Kwong Lo , Li Qian

We propose a schematic setup of quantum key distribution (QKD) with an improved secret key rate based on high-dimensional quantum states. Two degrees-of-freedom of a single photon, orbital angular momentum modes, and multi-path modes, are…

Quantum Physics · Physics 2019-01-29 Yonggi Jo , Hee Su Park , Seung-Woo Lee , Wonmin Son

This paper presents a novel hybrid Quantum Key Distribution ,QKD, protocol that combines entanglement based and non entanglement based approaches to optimize security and the number of generated keys. We introduce a dynamic system that…

We present a new fiber based quantum key distribution (QKD) scheme which can be regarded as a modification of an idea proposed by Inoue, Waks and Yamamoto (IWY) [1]. The scheme described here uses a single phase modulator and two…

Quantum Physics · Physics 2009-11-07 William T. Buttler , Justin R. Torgerson , Steven K. Lamoreaux

The phase randomized light is one of the key assumptions in the security proof of Bennett-Brassard 1984 (BB84) quantum key distribution (QKD) protocol implemented with an attenuated laser. Though the assumption has been believed to be…

Quantum Physics · Physics 2015-06-22 Toshiya Kobayashi , Akihisa Tomita , Atsushi Okamoto

Quantum key distribution (QKD) is a cryptographic technique that uses quantum mechanical principles to enable secure key exchange. Practical deployment of QKD requires robust, cost-effective systems that can operate in challenging field…

Quantum Physics · Physics 2026-04-07 Rui Guan , Jingchun Yu , Zhaoyun Li , Hongbo Xie , Yuxing Wei , Sen Li , Jing Wen , Xiaodong Liang , Yanwei Li , Kejin Wei

We demonstrate a novel transmitter concept for quantum key distribution based on the polarization-encoded BB84 protocol, which is sourced by the incoherent light of a forward-biased Ge-on-Si PIN junction. We investigate two architectures…

Quantum key distribution (QKD) allows two distant parties to share secret keys with the proven security even in the presence of an eavesdropper with unbounded computational power. Recently, GHz-clock decoy QKD systems have been realized by…

Quantum key distribution (QKD) leverages the principles of quantum mechanics to exchange a secret key between two parties. Despite its promising features, QKD also faces several practical challenges such as transmission loss, noise in…

The probabilistic model of keys generation of QKD systems is proposed. The model includes all phases of keys generation starting from photons generation to states detection taking characteristics of fiber-optics components into account. The…

Quantum Physics · Physics 2010-07-27 Dmitry Golubchikov , Konstantin Rumiantsev

Recently, Takeoka, Guha and Wilde have established a new (loose) upper bound on the secret key capacity of a pure-loss bosonic channel that is several times larger than an error-free BB84 QKD channel with same transmittance. This suggests…

Quantum Physics · Physics 2014-06-27 Richard J. Hughes , Jane E. Nordholt

Measurement-device-independent quantum key distribution (MDI-QKD) eliminates detector side-channel attacks by relocating all measurements to an untrusted intermediate node. However, its practical implementation critically relies on…

Quantum Physics · Physics 2025-12-22 A. P. Pljonkin

Entanglement is an essential ingredient in many quantum communication protocols. In particular, entanglement can be exploited in quantum key distribution (QKD) to generate two correlated random bit strings whose randomness is guaranteed by…