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Related papers: Long-fiber Sagnac interferometers for twin field q…

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We present a simple and robust design for a squeezing-enhanced Sagnac interferometer that employs the concept of SU(1,1) interference to significantly surpass the classical sensitivity limit (shot-noise limit - SNL) in rotational sensing.…

Quantum Physics · Physics 2026-02-05 Michal Natan , Saar Levin , Avi Pe'er

Several vulnerabilities of single photon detectors have recently been exploited to compromise the security of quantum key distribution (QKD) systems. In this letter we report the first proof-of-principle implementation of a new quantum key…

Quantum Physics · Physics 2013-10-03 Allison Rubenok , Joshua A. Slater , Philip Chan , Itzel Lucio-Martinez , Wolfgang Tittel

We present a practical method that can make quantum key distribution (QKD), for the first time, both ultra-long-distance and immune to all attacks in the detection system. This method is an important extension of the…

Quantum Physics · Physics 2013-08-22 Feihu Xu , Bing Qi , Zhongfa Liao , Hoi-Kwong Lo

Quantum communication has historically been at the forefront of advancements, from fundamental tests of quantum physics to utilizing the quantum-mechanical properties of physical systems for practical applications. In the field of…

We demonstrate a nontraditional design of the Sagnac interferometer by replacing the commonly used beam splitter with a linear-optical Grover multiport. This substitution creates a pole at the origin of the device parameter space with an…

The Sagnac effect has been shown in inertial frames as well as rotating frames. We solve the problem of the generalized Sagnac effect in the standard synchronization of clocks. The speed of a light beam that traverses an optical fiber loop…

General Physics · Physics 2017-10-11 Yang-Ho Choi

Polarization-encoded free-space Quantum Communication requires a quantum state source featuring fast polarization modulation, long-term stability and a low intrinsic error rate. Here we present a source based on a Sagnac interferometer and…

Quantum Physics · Physics 2020-08-27 Marco Avesani , Costantino Agnesi , Andrea Stanco , Giuseppe Vallone , Paolo Villoresi

We put forward a new fiber optic sensor for measuring linear velocity with picometer/second sensitivity with Weak-value amplification based on generalized Sagnac effect [Phys. Rev. Lett.\textbf{93}, 143901(2004)].The generalized Sagnac…

Quantum Physics · Physics 2021-10-13 Jing-Hui Huang , Xue-Ying Duan , Guang-Jun Wang , Xiang-Yun Hu

In the past two decades, quantum key distribution networks based on telecom fibers have been implemented on metropolitan and intercity scales. One of the bottlenecks lies in the exponential decay of the key rate with respect to the…

Quantum digital signatures (QDS) offer information-theoretic security for message integrity, authenticity, and non-repudiation, and constitute a fundamental cryptographic primitive for future quantum networks. Despite significant progress,…

A detailled analysis of quantum key distribution employing entangled states is presented. We tested a system based on photon pairs entangled in energy-time optimized for long distance transmission. It is based on a Franson type set-up for…

Quantum Physics · Physics 2009-11-06 Gregoire Ribordy , Juergen Brendel , Jean-Daniel Gautier , Nicolas Gisin , Hugo Zbinden

Optical phase measurements play a key role in the detection of macroscopic parameters such as position, velocity, and displacement. They also permit to qualify the microscopic properties of photonic waveguides such as polarization mode…

Quantum Physics · Physics 2024-12-19 Romain Dalidet , Laurent Labonté , Gregory Sauder , Sébastien Tanzilli , Anthony Martin

Proposed in 1984, quantum key distribution (QKD) allows two users to exchange provably secure keys via a potentially insecure quantum channel. Since then, QKD has attracted much attention and significant progress has been made in both…

Entanglement distribution via photons over long distances enables many applications, including quantum key distribution (QKD), which provides unprecedented privacy. The inevitable degradation of entanglement through noise accumulated over…

We have experimentally created a robust, ultrabright and phase-stable polarization-entangled state close to maximally entangled Bell-state with $ \% 98 $-fidelity using the type-II spontaneous parametric down-conversion (SPDC) process in…

Quantum Physics · Physics 2021-07-05 Ali Motazedifard , Seyed Ahmad Madani , J. Jafari Dashkasan , N. Sobhkhiz Vayaghan

Twin field quantum key distribution promises high key rates at long distance to beat the rate distance limit. Here, applying the sending or not sending TF QKD protocol, we experimentally demonstrate a secure key distribution breaking the…

The greater confinement of light that is possible in photonic crystal fibres leads to a greater effective nonlin- earity, which promises to yield greater quantum squeezing than is possible in standard optical fibre. However, experimental…

Quantum Physics · Physics 2015-06-15 Morgan J. Tacey , Joel F. Corney

Entanglement-based quantum key distribution (QKD) protocols, such as E91 and BBM92, offer strong information-theoretic security and are naturally suited for satellite-to-satellite QKD (SatQKD) links. However, implementing these protocols…

Signal Processing · Electrical Eng. & Systems 2025-06-27 Mohammad Taghi Dabiri , Mazen Hasna , Saif Al-Kuwari , Khalid Qaraqe

Twin-field quantum key distribution (TF-QKD) dramatically enhances the secure key rate (SKR) over inter-city distances through its square-root scaling. Further improvements in aggregate SKR can be achieved by wavelength-division…

Quantum key distribution (QKD) provides an attractive means for securing communications in optical fibre networks. However, deployment of the technology has been hampered by the frequent need for dedicated dark fibres to segregate the very…