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

arXiv:1308.0019 · Scientific Reports

Quantum key distribution session with 16-dimensional photonic states

S. Etcheverry, Gustavo Cañas, Esteban S. Gómez, W. A. T. Nogueira, C. Saavedra, GUILHERME BARRETO XAVIER, G. Lima

Published Jul 30, 2013• 129 citations
arXivHTMLPDF

Abstract

The secure transfer of information is an important problem in modern telecommunications. Quantum key distribution (QKD) provides a solution to this problem by using individual quantum systems to generate correlated bits between remote parties, that can be used to extract a secret key. QKD with D-dimensional quantum channels provides security advantages that grow with increasing D. However, the vast majority of QKD implementations has been restricted to two dimensions. Here we demonstrate the feasibility of using higher dimensions for real-world quantum cryptography by performing, for the first time, a fully automated QKD session based on the BB84 protocol with 16-dimensional quantum states. Information is encoded in the single-photon transverse momentum and the required states are dynamically generated with programmable spatial light modulators. Our setup paves the way for future developments in the field of experimental high-dimensional QKD.

DOI
10.1038/srep02316

Related papers

Two high-dimensional cartesian bases for quantum key distribution

Tristan Bernhard Horst Tentrup, Willemijn M. Luiten, Peter Hooijschuur +2 more

Quantum Key Distribution (QKD) provides a secure way of generating shared cryptographic keys between a sender (Alice) and a receiver (Bob). The original BB84 protocol uses a two-dimensional polarization basis, limiting the information content of a single photon to 1 bit. Using the transverse position of single photons as one basis and the Fourier space as a second basis, one can construct a pair of mutually unbiased higher-dimensional bases. This improves not only the security of the protocol, but also the key generation rate. We present experimental results with a Spatial-Light-Modulator-based encoding scheme employing two nearly orthogonal alphabets with on the order of 103symbols each and an information content of about 10 bit.

Workshop on Information Optics•Jul 1, 2017•1 citation

Experimental Demonstration of Free Space Quantum Key Distribution System based on the BB84 Protocol

Adarsh Jain, Abhishek Khanna, Jay B. Bhatt +2 more

Quantum key distribution (QKD) has emerged as a revolutionary technique that can ensure unconditionally secure communication between two distant parties, referred to as Alice and Bob, by exploiting the fundamental principles of quantum physics. Here, we report experimental demonstration of a fully automated QKD system based on the BB84 protocol. A weak coherent pulse source is developed to generate stream of polarization encoded single photons. Our QKD system demonstrates a low QBER of ∼1.2% with sifted key generation rate of ∼70 Kbps at an average photon number per pulse of$\mu=0.11$. The final secure key rate of ∼33 Kbps is achieved after performing post processing procedures viz. error correction and privacy amplification. The quantum communication link is established continuously for several hours and the performance is evaluated iteratively. The developed QKD system is shown to have the capability of distributing cryptographic keys securely and seamlessly, under practical operating conditions. Furthermore, we have successfully demonstrated unconditionally secure transmission and reception of an image between Alice and Bob connected over an unsecured public channel by utilizing quantum cryptography.

International Conference on Computing, Communication and Networking Technologies (ICCCNT)•Jul 1, 2020•11 citations

Efficient Time-Bin Encoding for Practical High-Dimensional Quantum Key Distribution

Ilaria Vagniluca, Beatrice Da Lio, Davide Rusca +6 more

High-dimensional quantum key distribution (QKD) allows achievement of information-theoretic secure communications, providing high key-generation rates, which cannot, in principle, be obtained by QKD protocols with binary encoding. Nonetheless, the amount of experimental resources needed increases as the quantum states to be detected belong to a larger Hilbert space, thus raising the costs of practical high-dimensional systems. Here, we present an alternative scheme for fiber-based four-dimensional QKD, with time and phase encoding and one-decoy state technique. Quantum state transmission is tested over different channel lengths up to 145 km of standard single-mode fiber, evaluating the enhancement of the secret key rate in comparison to the three-state two-dimensional BB84 protocol, which is tested with the same experimental setup. Our scheme allows measurement of the four-dimensional states with a simplified and compact receiver, where only two single-photon detectors are necessary, thus making it a cost-effective solution for practical and fiber-based QKD.

arXiv:2004.03498•Physical Review Applied•Jul 17, 2020•114 citations

High-dimensional intracity quantum cryptography with structured photons

Alicia Sit, Frédéric Bouchard, Robert Fickler +11 more

Quantum key distribution (QKD) promises information-theoretically secure communication, and is already on the verge of commercialization. Thus far, different QKD protocols have been proposed theoretically and implemented experimentally [1, 2]. The next step will be to implement high-dimensional protocols in order to improve noise resistance and increase the data rate [3-7]. Hitherto, no experimental verification of high-dimensional QKD in the single-photon regime has been conducted outside of the laboratory. Here, we report the realization of such a single-photon QKD system in a turbulent free-space link of 0.3 km over the city of Ottawa, taking advantage of both the spin and orbital angular momentum photonic degrees of freedom. This combination of optical angular momenta allows us to create a 4-dimensional state [8]; wherein, using a high-dimensional BB84 protocol [3, 4], a quantum bit error rate of 11\% was attained with a corresponding secret key rate of 0.65 bits per sifted photon. While an error rate of 5\% with a secret key rate of 0.43 bits per sifted photon is achieved for the case of 2-dimensional structured photons. Even through moderate turbulence without active wavefront correction, it is possible to securely transmit information carried by structured photons, opening the way for intra-city high-dimensional quantum communications under realistic conditions.

arXiv:1612.05195•Optica•Aug 24, 2017•537 citations

High-dimensional decoy-state quantum key distribution over multicore telecommunication fibers

Gustavo Cañas, Nicolás Vera, Jaime Cariñe +11 more

Multiplexing is a strategy to augment the transmission capacity of a communication system. It consists of combining multiple signals over the same data channel and it has been very successful in classical communications. However, the use of enhanced channels has only reached limited practicality in quantum communications (QC) as it requires the manipulation of quantum systems of higher dimensions. Considerable effort is being made towards QC using high-dimensional quantum systems encoded into the transverse momentum of single photons, but so far no approach has been proven to be fully compatible with the existing telecommunication fibers. Here we overcome such a challenge and demonstrate a secure high-dimensional decoy-state quantum key distribution session over a 300-m-long multicore optical fiber. The high-dimensional quantum states are defined in terms of the transverse core modes available for the photon transmission over the fiber, and theoretical analyses show that positive secret key rates can be achieved through metropolitan distances.

arXiv:1610.01682•Physical Review A•Aug 18, 2017•137 citations

Analogy of free-space quantum key distribution using spatial modes of light: scaling up the distance and the dimensionality

Joseph Meyer, Yuval Reches, Georgi Gary Rozenman +3 more

While quantum key distribution (QKD) shows much potential as a solution to the looming threat that quantum computers place on today’s encryption protocols, efficient and robust systems that operate in free space are still limited. In this paper, we present a classical light analogy of QKD using spatial modes of light, which can provide a higher bit per photon rate than the more commonly used polarization state encoding.We start by demonstrating the BB84 protocol indoors, where we achieve a secure key rate of 1.55 bits per sifted photon. Then, using our outdoor environment, we propagate the signal outdoors over a distance of up to 90 m, modeling the real-world challenges of QKD in free-space applications and successfully demonstrating BB84 for dimensions 2 and 4.

Optics Letters•Apr 11, 2025•19 citations
The secure transfer of information is an important problem in modern telecommunications. Quantum key distribution (QKD) provides a solution to this problem by using individual quantum systems to generate correlated bits between remote parties, that can be used to extract a secret key. QKD with D-dimensional quantum channels provides security advantages that grow with increasing D. However, the vast majority of QKD implementations has been restricted to two dimensions. Here we demonstrate the feasibility of using higher dimensions for real-world quantum cryptography by performing, for the first time, a fully automated QKD session based on the BB84 protocol with 16-dimensional quantum states. Information is encoded in the single-photon transverse momentum and the required states are dynamically generated with programmable spatial light modulators. Our setup paves the way for future developments in the field of experimental high-dimensional QKD.
Quantum Key Distribution (QKD) provides a secure way of generating shared cryptographic keys between a sender (Alice) and a receiver (Bob). The original BB84 protocol uses a two-dimensional polarization basis, limiting the information content of a single photon to 1 bit. Using the transverse position of single photons as one basis and the Fourier space as a second basis, one can construct a pair of mutually unbiased higher-dimensional bases. This improves not only the security of the protocol, but also the key generation rate. We present experimental results with a Spatial-Light-Modulator-based encoding scheme employing two nearly orthogonal alphabets with on the order of 103symbols each and an information content of about 10 bit.
Quantum key distribution (QKD) has emerged as a revolutionary technique that can ensure unconditionally secure communication between two distant parties, referred to as Alice and Bob, by exploiting the fundamental principles of quantum physics. Here, we report experimental demonstration of a fully automated QKD system based on the BB84 protocol. A weak coherent pulse source is developed to generate stream of polarization encoded single photons. Our QKD system demonstrates a low QBER of ∼1.2% with sifted key generation rate of ∼70 Kbps at an average photon number per pulse ofμ=0.11\mu=0.11μ=0.11. The final secure key rate of ∼33 Kbps is achieved after performing post processing procedures viz. error correction and privacy amplification. The quantum communication link is established continuously for several hours and the performance is evaluated iteratively. The developed QKD system is shown to have the capability of distributing cryptographic keys securely and seamlessly, under practical operating conditions. Furthermore, we have successfully demonstrated unconditionally secure transmission and reception of an image between Alice and Bob connected over an unsecured public channel by utilizing quantum cryptography.
High-dimensional quantum key distribution (QKD) allows achievement of information-theoretic secure communications, providing high key-generation rates, which cannot, in principle, be obtained by QKD protocols with binary encoding. Nonetheless, the amount of experimental resources needed increases as the quantum states to be detected belong to a larger Hilbert space, thus raising the costs of practical high-dimensional systems. Here, we present an alternative scheme for fiber-based four-dimensional QKD, with time and phase encoding and one-decoy state technique. Quantum state transmission is tested over different channel lengths up to 145 km of standard single-mode fiber, evaluating the enhancement of the secret key rate in comparison to the three-state two-dimensional BB84 protocol, which is tested with the same experimental setup. Our scheme allows measurement of the four-dimensional states with a simplified and compact receiver, where only two single-photon detectors are necessary, thus making it a cost-effective solution for practical and fiber-based QKD.
Quantum key distribution (QKD) promises information-theoretically secure communication, and is already on the verge of commercialization. Thus far, different QKD protocols have been proposed theoretically and implemented experimentally [1, 2]. The next step will be to implement high-dimensional protocols in order to improve noise resistance and increase the data rate [3-7]. Hitherto, no experimental verification of high-dimensional QKD in the single-photon regime has been conducted outside of the laboratory. Here, we report the realization of such a single-photon QKD system in a turbulent free-space link of 0.3 km over the city of Ottawa, taking advantage of both the spin and orbital angular momentum photonic degrees of freedom. This combination of optical angular momenta allows us to create a 4-dimensional state [8]; wherein, using a high-dimensional BB84 protocol [3, 4], a quantum bit error rate of 11\% was attained with a corresponding secret key rate of 0.65 bits per sifted photon. While an error rate of 5\% with a secret key rate of 0.43 bits per sifted photon is achieved for the case of 2-dimensional structured photons. Even through moderate turbulence without active wavefront correction, it is possible to securely transmit information carried by structured photons, opening the way for intra-city high-dimensional quantum communications under realistic conditions.
Multiplexing is a strategy to augment the transmission capacity of a communication system. It consists of combining multiple signals over the same data channel and it has been very successful in classical communications. However, the use of enhanced channels has only reached limited practicality in quantum communications (QC) as it requires the manipulation of quantum systems of higher dimensions. Considerable effort is being made towards QC using high-dimensional quantum systems encoded into the transverse momentum of single photons, but so far no approach has been proven to be fully compatible with the existing telecommunication fibers. Here we overcome such a challenge and demonstrate a secure high-dimensional decoy-state quantum key distribution session over a 300-m-long multicore optical fiber. The high-dimensional quantum states are defined in terms of the transverse core modes available for the photon transmission over the fiber, and theoretical analyses show that positive secret key rates can be achieved through metropolitan distances.
While quantum key distribution (QKD) shows much potential as a solution to the looming threat that quantum computers place on today’s encryption protocols, efficient and robust systems that operate in free space are still limited. In this paper, we present a classical light analogy of QKD using spatial modes of light, which can provide a higher bit per photon rate than the more commonly used polarization state encoding.We start by demonstrating the BB84 protocol indoors, where we achieve a secure key rate of 1.55 bits per sifted photon. Then, using our outdoor environment, we propagate the signal outdoors over a distance of up to 90 m, modeling the real-world challenges of QKD in free-space applications and successfully demonstrating BB84 for dimensions 2 and 4.