scholarly journals Quantum cryptography with highly entangled photons from semiconductor quantum dots

2021 ◽  
Vol 7 (16) ◽  
pp. eabe8905
Author(s):  
Christian Schimpf ◽  
Marcus Reindl ◽  
Daniel Huber ◽  
Barbara Lehner ◽  
Saimon F. Covre Da Silva ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Key Distribution ◽  
Key Distribution ◽  
Semiconductor Quantum Dots ◽  
Light Sources ◽  
Key Generation ◽  
Quantum Networks ◽  
Pumping Rate ◽  
Excitation Rate ◽  
Quantum Bit

Semiconductor quantum dots are capable of emitting polarization entangled photon pairs with ultralow multipair emission probability even at maximum brightness. Using a quantum dot source with a fidelity as high as 0.987(8), we implement here quantum key distribution with an average quantum bit error rate as low as 1.9% over a time span of 13 hours. For a proof of principle, the key generation is performed with the BBM92 protocol between two buildings, connected by a 350-m-long fiber, resulting in an average raw (secure) key rate of 135 bits/s (86 bits/s) for a pumping rate of 80 MHz, without resorting to time- or frequency-filtering techniques. Our work demonstrates the viability of quantum dots as light sources for entanglement-based quantum key distribution and quantum networks. By increasing the excitation rate and embedding the dots in state-of-the-art photonic structures, key generation rates in the gigabits per second range are in principle at reach.

Urban QKD test for phase and polarization encoding devices

2017 ◽  
Vol 15 (08) ◽  
pp. 1740018
Author(s):  
Alan Kanapin ◽  
Alexander Duplinskiy ◽  
Alexander Sokolov ◽  
Sergey Vorobey ◽  
Alexander Miller ◽  
...  
Keyword(s):  
Bit Error Rate ◽  
Quantum Key Distribution ◽  
Key Distribution ◽  
Optical Scheme ◽  
Communication Line ◽  
Key Generation ◽  
Phase Encoding ◽  
Fiber Communication ◽  
Quantum Bit ◽  
Polarization Encoding

In this work, the results of quantum key distribution through an urban fiber communication line with a length of 30.6[Formula: see text]km and losses of 11.7[Formula: see text]dB, obtained by both phase and polarization encoding-based devices, are presented. For phase encoding, a two-pass auto-compensating optical scheme, commonly called “plug&play”, was used. For polarization encoding, a self-developed unconventional optical scheme was made. A continuous key distribution with a sifted key generation rate of 1.0[Formula: see text]kbit/s and a quantum bit error rate of 5.7% was implemented when using “plug&play” device, whereas 0.1[Formula: see text]kbit/s and 5.5% was observed when using one with polarization encoding. The features and conveniences of both implementations are discussed.

scholarly journals Quantum key distribution in terms of the Greenberger-Horne-Zeilinger state: Multi-key generation

Laser Physics ◽  
2010 ◽  
Vol 20 (5) ◽  
pp. 1210-1214 ◽  
Author(s):  
F. A. A. El-Orany ◽  
M. R. B. Wahiddin ◽  
M. -A. Mat-Nor ◽  
N. Jamil ◽  
I. Bahari
Keyword(s):  
Quantum Key Distribution ◽  
Key Distribution ◽  
Key Generation

scholarly journals Full daylight quantum-key-distribution at 1550 nm enabled by integrated silicon photonics

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
M. Avesani ◽  
L. Calderaro ◽  
M. Schiavon ◽  
A. Stanco ◽  
C. Agnesi ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Silicon Photonics ◽  
Free Space ◽  
Quantum Key Distribution ◽  
Cost Effective ◽  
Key Distribution ◽  
Global Scale ◽  
Secret Key ◽  
Quantum Bit ◽  
Integrated Silicon Photonics

AbstractThe future envisaged global-scale quantum-communication network will comprise various nodes interconnected via optical fibers or free-space channels, depending on the link distance. The free-space segment of such a network should guarantee certain key requirements, such as daytime operation and the compatibility with the complementary telecom-based fiber infrastructure. In addition, space-to-ground links will require the capability of designing light and compact quantum devices to be placed in orbit. For these reasons, investigating available solutions matching all the above requirements is still necessary. Here we present a full prototype for daylight quantum key distribution at 1550 nm exploiting an integrated silicon-photonics chip as state encoder. We tested our prototype in the urban area of Padua (Italy) over a 145 m-long free-space link, obtaining a quantum bit error rate around 0.5% and an averaged secret key rate of 30 kbps during a whole sunny day (from 11:00 to 20:00). The developed chip represents a cost-effective solution for portable free-space transmitters and a promising resource to design quantum optical payloads for future satellite missions.

scholarly journals Non-Poissonian statistics from Poissonian light sources with application to passive decoy state quantum key distribution

2009 ◽  
Vol 34 (20) ◽  
pp. 3238 ◽  
Author(s):  
Marcos Curty ◽  
Tobias Moroder ◽  
Xiongfeng Ma ◽  
Norbert Lütkenhaus
Keyword(s):  
Quantum Key Distribution ◽  
Key Distribution ◽  
Light Sources ◽  
Decoy State ◽  
Poissonian Statistics

scholarly journals DECOY STATE QUANTUM KEY DISTRIBUTION

2005 ◽  
Vol 03 (supp01) ◽  
pp. 143-143 ◽  
Author(s):  
HOI-KWONG LO
Keyword(s):  
Quantum Key Distribution ◽  
Secure Communication ◽  
Key Distribution ◽  
Generation Rate ◽  
Key Generation ◽  
Long Distance ◽  
Decoy State ◽  
Bb84 Protocol ◽  
High Loss ◽  
Statistical Fluctuations

Quantum key distribution (QKD) allows two parties to communicate in absolute security based on the fundamental laws of physics. Up till now, it is widely believed that unconditionally secure QKD based on standard Bennett-Brassard (BB84) protocol is limited in both key generation rate and distance because of imperfect devices. Here, we solve these two problems directly by presenting new protocols that are feasible with only current technology. Surprisingly, our new protocols can make fiber-based QKD unconditionally secure at distances over 100km (for some experiments, such as GYS) and increase the key generation rate from O(η2) in prior art to O(η) where η is the overall transmittance. Our method is to develop the decoy state idea (first proposed by W.-Y. Hwang in "Quantum Key Distribution with High Loss: Toward Global Secure Communication", Phys. Rev. Lett. 91, 057901 (2003)) and consider simple extensions of the BB84 protocol. This part of work is published in "Decoy State Quantum Key Distribution", . We present a general theory of the decoy state protocol and propose a decoy method based on only one signal state and two decoy states. We perform optimization on the choice of intensities of the signal state and the two decoy states. Our result shows that a decoy state protocol with only two types of decoy states—a vacuum and a weak decoy state—asymptotically approaches the theoretical limit of the most general type of decoy state protocols (with an infinite number of decoy states). We also present a one-decoy-state protocol as a special case of Vacuum+Weak decoy method. Moreover, we provide estimations on the effects of statistical fluctuations and suggest that, even for long distance (larger than 100km) QKD, our two-decoy-state protocol can be implemented with only a few hours of experimental data. In conclusion, decoy state quantum key distribution is highly practical. This part of work is published in "Practical Decoy State for Quantum Key Distribution", . We also have done the first experimental demonstration of decoy state quantum key distribution, over 15km of Telecom fibers. This part of work is published in "Experimental Decoy State Quantum Key Distribution Over 15km", .

scholarly journals The Influence of Signal Polarization on Quantum Bit Error Rate for Subcarrier Wave Quantum Key Distribution Protocol

Entropy ◽  
2020 ◽  
Vol 22 (12) ◽  
pp. 1393
Author(s):  
Andrei Gaidash ◽  
Anton Kozubov ◽  
Svetlana Medvedeva ◽  
George Miroshnichenko
Keyword(s):  
Optical Fiber ◽  
Bit Error Rate ◽  
Error Rate ◽  
Quantum Key Distribution ◽  
Key Distribution ◽  
Stokes Parameters ◽  
Second Phase ◽  
Quantum Bit ◽  
Quantum Bit Error Rate ◽  
Quantum Key Distribution Protocol

In this paper, we consider the influence of a divergence of polarization of a quantum signal transmitted through an optical fiber channel on the quantum bit error rate of the subcarrier wave quantum key distribution protocol. Firstly, we investigate the dependence of the optical power of the signal on the modulation indices’ difference after the second phase modulation of the signal. Then we consider the Liouville equation with regard to relaxation in order to develop expressions of the dynamics of the Stokes parameters. As a result, we propose a model that describes quantum bit error rate for the subcarrier wave quantum key distribution depending on the characteristics of the optical fiber. Finally, we propose several methods for minimizing quantum bit error rate.

The enhanced measurement-device-independent quantum key distribution with heralded pair coherent state

2019 ◽  
Vol 34 (04) ◽  
pp. 2050063
Author(s):  
Yefeng He ◽  
Wenping Ma
Keyword(s):  
Light Source ◽  
Error Rate ◽  
Quantum Key Distribution ◽  
Key Distribution ◽  
Generation Rate ◽  
Key Generation ◽  
Measurement Device ◽  
Decoy State ◽  
Communication Distance ◽  
Measurement Device Independent

With heralded pair coherent states (HPCS), orbital angular momentum (OAM) states and pulse position modulation (PPM) technology, a decoy-state measurement-device-independent quantum key distribution (MDI-QKD) protocol is proposed. OAM states and PPM technology are used to realize the coding of the signal states in the HPCS light source. The use of HPCS light source, OAM coding and PPM coding cannot only reduce the error rate but also improve the key generation rate and communication distance. The new MDI-QKD protocol also employs three-intensity decoy states to avoid the attacks against the light source. By calculating the error rate and key generation rate, the performance of the MDI-QKD protocol is analyzed. Numerical simulation shows that the protocol has very low error rate and very high key generation rate. Moreover, the maximum communication distance can reach 455 km.

An Efficient Reconciliation in Removing Errors Using Bose, Chaudhuri, Hocquenghem Code for Quantum Key Distribution

2012 ◽  
pp. 13-19
Author(s):  
Riaz Ahmad Qamar ◽  
Mohd Aizaini Maarof ◽  
Subariah Ibrahim
Keyword(s):  
Bit Error Rate ◽  
Error Rate ◽  
Quantum Key Distribution ◽  
Error Probability ◽  
Key Distribution ◽  
Secret Key ◽  
Post Processing ◽  
Quantum Bit ◽  
Quantum Bit Error Rate ◽  
Quantum Key Distribution Protocol

A quantum key distribution protocol(QKD), known as BB84, was developed in 1984 by Charles Bennett and Gilles Brassard. The protocol works in two phases which are quantum state transmission and conventional post processing. In the first phase of BB84, raw key elements are distributed between two legitimate users by sending encoded photons through quantum channel whilst in the second phase, a common secret-key is obtained from correlated raw key elements by exchanging messages through a public channel e.g.; network or internet. The secret-key so obtained is used for cryptography purpose. Reconciliation is a compulsory part of post processing and hence of quantum key distribution protocol. The performance of a reconciliation protocol depends on the generation rate of common secret-key, number of bits disclosed and the error probability in common secrete-key. These characteristics of a protocol can be achieved by using a less interactive reconciliation protocol which can handle a higher initial quantum bit error rate (QBER). In this paper, we use a simple Bose, Chaudhuri, Hocquenghem (BCH) error correction algorithm with simplified syndrome table to achieve an efficient reconciliation protocol which can handle a higher quantum bit error rate and outputs a common key with zero error probability. The proposed protocol efficient in removing errors such that it can remove all errors even if QBER is 60%. Assuming the post processing channel is an authenticated binary symmetric channel (BSC).

Theory of Quantum Light Sources and Cavity-QED Emitters Based on Semiconductor Quantum Dots

2017 ◽  
pp. 3-40 ◽  
Author(s):  
Christopher Gies ◽  
Matthias Florian ◽  
Alexander Steinhoff ◽  
Frank Jahnke
Keyword(s):  
Quantum Dots ◽  
Cavity Qed ◽  
Semiconductor Quantum Dots ◽  
Light Sources
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