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

AIP conference proceedings

Quantum key distribution for ultra-long distances based on microsatellites

V. L. Kurochkin, Alexander V. Miller, V.E. Rodimin, S. Vorobey, M. Yu. Balanov, Yury Kurochkin

Published Jan 1, 2019• 2 citations
Publisher

Abstract

The authors of this work made a device for free space quantum key distribution with using of polarization encoding, operating at frequencies of 0.3–1.6 GHz. According to BB84 protocol, the polarization states of photons, with a wavelength of 1.55 µm, are being used for encoding information. At the probability to find a photon in single pulses of 0.20, there is a sifted quantum key distribution rate of 170 kbps with the corresponding quantum bit error rate of 1.4 %. At short distances between the transmitter and the receiver, the possibility of quantum key distribution with phase encoding was experimentally proved.

DOI
10.1063/1.5089839

Related papers

Study of Long-Term Stability of Free-Space Quantum Key Distribution at a Distance of 20 m in a Polarization Coding Scheme

A. S. Pleshkov, A. V. Kolyako, Denis B. Tretyakov +2 more

The operation of our atmospheric quantum cryptography system using the BB84 protocol and polarization coding is experimentally studied. The distribution rate of the sifted quantum key and the quantum bit error rate in the key remained constant for 1 hour and were $$7558\pm 83$$ bit s $${}^{-1}$$ and $$5.1\pm 0.84\%$$ , respectively, at the distance of 20 m between the transmitter and receiver. The minimum possible transmittance of a quantum channel, ensuring the security of a quantum key, is calculated for the given parameters of the system

Optoelectronics Instrumentation and Data Processing•Feb 1, 2024•2 citations

Investigation of Long-Term Stability of Single-Photon Quantum Key Distribution in a Polarization Coding Scheme

A. V. Kolyako, A. S. Pleshkov, Denis B. Tretyakov +3 more

Experimental results demonstrating long-term stability of the operation of our atmospheric quantum cryptography setup using the BB84 protocol and polarization coding are presented. It was shown that the “sifted” quantum key distribution rate and the quantum bit error rate in the key remained constant for 1 hour and were equal to 10 kbit/s and 6.5 %, respectively, at a distance between the transmitter and the receiver equal to 20 cm. Theoretical dependences of the secret quantum key generation rate on a quantum channel transmission coefficient for single-photon detectors, which were used in this experiment, and for new detectors with a reduced level of dark pulses are given.

Siberian Journal of Physics•Jan 12, 2022•3 citations

Implementation of polarization-coded free-space BB84 quantum key distribution

Y. S. Kim, Y. -C. Jeong, Y. S. Kim

We report on the implementation of a Bennett-Brassard 1984 quantum key distribution protocol over a free-space optical path on an optical table. Attenuated laser pulses and Pockels cells driven by a pseudorandom number generator are employed to prepare polarization-encoded photons. The sifted key generation rate of 23.6 kbits per second and the quantum bit error rate (QBER) of 3% have been demonstrated at the average photon number per pulse μ = 0.16. This QBER is sufficiently low to extract final secret keys from shared sifted keys via error correction and privacy amplification. We also tested the long-distance capability of our system by adding optical losses to the quantum channel and found that the QBER remains the same regardless of the loss.

Laser Physics•Jun 1, 2008•30 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

High-Speed Free-Space Quantum Key Distribution

Ricardo Figueiredo Ferreira

The goal of cryptography is to encode data in such a way that no one can decode it unless they are the intended recipient. With the emergence of quantum computing, classical cryptography is not reliable enough to protect sensitive information. Nevertheless, there are alternatives. Quantum Key Distribution (QKD) is a method to secure communication based on the laws of quantum physics. Due to being impossible to measure the quantum state of a system without disturbing it, QKD provides a way to communicate between two parties while being, in theory, immune to eavesdropping. In this work, a free-space high-speed QKD setup is proposed, with the objective of implementing the polarization three-state one-decoy variant of the BB84 protocol. An assessment of the best type of laser diode to use for free-space QKD is made between several options. The system’s performance was assessed, incorporating a quantitative analysis of system losses and an estimation of the number of photons traversing the quantum channel. The system achieved a Quantum Bit Error Rate (QBER) of 1.58% for the Z basis and 1.46% for the X basis, for an average reception of two photons per pulse. Preliminary QBER measurements were also undertaken in the context of Quantum Keyless Private Communication protocols, focusing on the average number of photons per pulse.

•May 12, 2023•0 citations

Quantum key distribution system operating at sifted-key rate over 4 Mbit/s

Xiao Hong Tang, Lijun Ma, Alan Mink +8 more

A complete fiber-based polarization encoding quantum key distribution (QKD) system based on the BB84 protocol has been developed at National Institute of Standard and Technology (NIST). The system can be operated at a sifted key rate of more than 4 Mbit/s over optical fiber of length 1 km and mean photon number 0.1. The quantum channel uses 850 nm photons from attenuated high speed VCSELs and the classical channel uses 1550 nm light from normal commercial coarse wavelength division multiplexing devices. Sifted-key rates and quantum error rates at different transmission rates are measured as a function of distance (fiber length). A polarization auto-compensation module has been developed and utilized to recover the polarization state and to compensate for temporal drift. An automatic timing alignment device has also been developed to quickly handle the initial configuration of quantum channels so that detection events fall into the correct timing window. These automated functions make the system more practical for integration into existing optical local area networks.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•May 5, 2006•10 citations
The authors of this work made a device for free space quantum key distribution with using of polarization encoding, operating at frequencies of 0.3–1.6 GHz. According to BB84 protocol, the polarization states of photons, with a wavelength of 1.55 µm, are being used for encoding information. At the probability to find a photon in single pulses of 0.20, there is a sifted quantum key distribution rate of 170 kbps with the corresponding quantum bit error rate of 1.4 %. At short distances between the transmitter and the receiver, the possibility of quantum key distribution with phase encoding was experimentally proved.
The operation of our atmospheric quantum cryptography system using the BB84 protocol and polarization coding is experimentally studied. The distribution rate of the sifted quantum key and the quantum bit error rate in the key remained constant for 1 hour and were 7558±837558\pm 837558±83 bit s −1{}^{-1}−1 and 5.1±0.84%5.1\pm 0.84\%5.1±0.84% , respectively, at the distance of 20 m between the transmitter and receiver. The minimum possible transmittance of a quantum channel, ensuring the security of a quantum key, is calculated for the given parameters of the system
Experimental results demonstrating long-term stability of the operation of our atmospheric quantum cryptography setup using the BB84 protocol and polarization coding are presented. It was shown that the “sifted” quantum key distribution rate and the quantum bit error rate in the key remained constant for 1 hour and were equal to 10 kbit/s and 6.5 %, respectively, at a distance between the transmitter and the receiver equal to 20 cm. Theoretical dependences of the secret quantum key generation rate on a quantum channel transmission coefficient for single-photon detectors, which were used in this experiment, and for new detectors with a reduced level of dark pulses are given.
We report on the implementation of a Bennett-Brassard 1984 quantum key distribution protocol over a free-space optical path on an optical table. Attenuated laser pulses and Pockels cells driven by a pseudorandom number generator are employed to prepare polarization-encoded photons. The sifted key generation rate of 23.6 kbits per second and the quantum bit error rate (QBER) of 3% have been demonstrated at the average photon number per pulse μ = 0.16. This QBER is sufficiently low to extract final secret keys from shared sifted keys via error correction and privacy amplification. We also tested the long-distance capability of our system by adding optical losses to the quantum channel and found that the QBER remains the same regardless of the loss.
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.
The goal of cryptography is to encode data in such a way that no one can decode it unless they are the intended recipient. With the emergence of quantum computing, classical cryptography is not reliable enough to protect sensitive information. Nevertheless, there are alternatives. Quantum Key Distribution (QKD) is a method to secure communication based on the laws of quantum physics. Due to being impossible to measure the quantum state of a system without disturbing it, QKD provides a way to communicate between two parties while being, in theory, immune to eavesdropping. In this work, a free-space high-speed QKD setup is proposed, with the objective of implementing the polarization three-state one-decoy variant of the BB84 protocol. An assessment of the best type of laser diode to use for free-space QKD is made between several options. The system’s performance was assessed, incorporating a quantitative analysis of system losses and an estimation of the number of photons traversing the quantum channel. The system achieved a Quantum Bit Error Rate (QBER) of 1.58% for the Z basis and 1.46% for the X basis, for an average reception of two photons per pulse. Preliminary QBER measurements were also undertaken in the context of Quantum Keyless Private Communication protocols, focusing on the average number of photons per pulse.
A complete fiber-based polarization encoding quantum key distribution (QKD) system based on the BB84 protocol has been developed at National Institute of Standard and Technology (NIST). The system can be operated at a sifted key rate of more than 4 Mbit/s over optical fiber of length 1 km and mean photon number 0.1. The quantum channel uses 850 nm photons from attenuated high speed VCSELs and the classical channel uses 1550 nm light from normal commercial coarse wavelength division multiplexing devices. Sifted-key rates and quantum error rates at different transmission rates are measured as a function of distance (fiber length). A polarization auto-compensation module has been developed and utilized to recover the polarization state and to compensate for temporal drift. An automatic timing alignment device has also been developed to quickly handle the initial configuration of quantum channels so that detection events fall into the correct timing window. These automated functions make the system more practical for integration into existing optical local area networks.