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

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE

Acquisition and tracking system for 100km quantum entanglement distribution experiment

Bo Qi, Hongbin Chen, Ge Ren, Yongmei Huang, Juan Yin, Ji-Gang Ren

Published Aug 21, 2013• 6 citations
Publisher

Abstract

Quantum entanglement is the main resource to endow the field of quantum information processing with powers that exceed those of classical communication and computation. Due to low absorption and negligible nonbirefringent character in atmosphere, optical free space therefore serves as the most promising channel for large-scale quantum communication by use of satellites and ground stations. The acquisition, tracking and pointing (ATP) system is one of the most important parts of quantum experiment system, and it controls a transmitting and receiving laser beam within a few micro radians jitter because of using an extremely narrow beam divergence of several micro radians. This paper introduces the cascade ATP systems for 100km quantum entanglement distribution experiment among Charlie, Bob and Alice station. The specification and optical diagram of each ATP system are presented. The ATP system of Alice station is described in detail，it has coarse, fine and ultra-fine loop. In the 100km quantum entanglement distribution experiment, a tracking error of 4μrad is achieved for 70Hz bandwidth. The ATP strategy in this experiment can be used in the prospective satellite-to-ground quantum distribution.

DOI
10.1117/12.2034706

Related papers

ATP technology for 100-kilometer quantum entanglement distribution experiment

亓波 Qi Bo, 陈洪斌 Chen Hongbin, 任戈 Ren Ge +3 more

Acquiring,tracking and pointing(ATP) technique in a 100 km quantum entanglement distribution experiment was introduced in detail.By taking a 700 mm telescope at Alice receiving terminal as an example,the technological specification,light path layout,and tracking accuracy of the ATP system were analyzed.In order to reduce the angle-of-arrival fluctuations of quantum information transmission beams and beacon beams caused by air turbulence,a cascade acquisition and tracking system with coarse tracking,fine tracking and a ultra-fine loop was designed and a dual fast-steering mirror tracking algorithm was proposed.On the basis of a higher frame frequency CMOS detector and a piezoelectric fast-steering mirror,the ultra-fine tracking circuit was developed.Experiments show that these methods solve the contradiction between tracking dynamic range and tracking accuracy,promote the performance of the detector and improve band width and tracking accuracy.The system was used in a ground 100 km quantum entanglement distribution experiment and the results indicate that the tracking error of the system is 4 μrad for a 70 Hz bandwidth.

Optics and Precision Engineering•Jan 1, 2013•2 citations

Validating the Satellite Tracking Strategy of the Singapore Optical Ground Station

Abdillah Shaik, Moritz Mihm, Muskan Varshney +2 more

The development of space-based quantum communication is a critical step toward establishing global-scale secure networks. Quantum communication via satellites enables long-distance key exchange beyond the limitations of terrestrial fiber networks. To support such missions, robust optical ground stations are essential for maintaining high-fidelity quantum links with orbiting platforms. Commissioned in early 2024, the Singapore Optical Ground Station is the first dedicated facility of its kind located near the equator. Its equatorial position enables frequent access to satellites in a wide range of orbital inclinations, making it uniquely suited for supporting diverse global quantum networks. Its receiving optics can accommodate quantum links across a broad range of wavelengths and support various encoding schemes, including polarization and phase. In this work, detailed results from preliminary testing of the pointing, acquisition, and tracking system for low Earth orbit satellites are presented. For LEO satellites, a tracking accuracy reaching 50 microradians, approaching the local atmospheric seeing limit was achieved.Tracking stability is maintained using a hybrid feedback control loop designed to accommodate sporadic link losses caused by cloud cover. These results demonstrate the readiness of the SOGS to support current and future missions towards satellite quantum networks.

IEEE International Conference on Space Optical Systems and Applications (ICSOS)•Oct 28, 2025•0 citations

Towards Quantum Laser Links between nano-satellites in Low Earth Orbit (Conference Presentation)

Andrew J. Lambert

Designing a laser communications payload integral to a nano-satellite, capable of fine pointing, is a difficult task. Integrating this with a quantum key distribution payload for inter-satellite secure communication adds significant complexity, as does ground based communication with the moving objects in low Earth orbit. The advantages of low path length, secure, global communication make this an opportunity not to be missed. We report on developments of such a system. Beginning with a satellite demonstrator with a Pointing, Acquisition-and Tracking system that involves fine precision star-tracker, plasma and aerodynamic force interactions for steering, and an inter-satellite laser link demonstration on orbit using LED beacon for acquisition, and laser for communications link closure. Combining design studies for a nano-satellite quantum payload for transferring entangled photon-pairs between the satellites at long-range in Low Earth Orbit, and incorporating ground to space and space to ground laser communications, are described in the context of quantum optical ground station efforts within Australia.

•Oct 18, 2019•0 citations

Entanglement distribution via satellite: An evaluation of competing protocols assuming realistic free-space optical channels

Nicholas Zaunders, Timothy C. Ralph

A key technical requirement of any future quantum network is the ability to distribute quantum-entangled resources between two spatially separated points at a high rate and high fidelity. Entanglement distribution protocols based on satellite platforms, which transmit and receive quantum resources directly via free-space optical propagation, are therefore excellent candidates for quantum networking, since the geometry and loss characteristics of satellite networks feasibly allow for up to continental-scale ($\sim10^3$ km) over-the-horizon communication without the infrastructure, cost, or losses associated with equivalent fibre-optic networks. In this work, we explore two network topologies commonly associated with quantum networks - entanglement distribution between two satellites in low-Earth orbit mediated by a third satellite and entanglement distribution between two ground stations mediated by a satellite in low-Earth orbit, and two entanglement distribution schemes - one where the central satellite is used as a relay, and the other where the central satellite is used to generate and distribute the entangled resource directly. We compute a bound on the rate of distribution of distillable entanglement achieved by each protocol in each network topology as a function of the network channels for both single-rail discrete- (DV) and continuous-variable (CV) resources and use or non-use of probabilistic noiseless linear quantum amplification (NLA). In the case of atmospheric channels we take into account the turbulent and optical properties of the free-space propagation. We determine that for the triple-satellite network configuration, the optimal strategy is to perform a distributed NLA scheme in either CV or DV, and for the ground-satellite-ground network the optimal strategy is to distribute a DV resource via the central satellite.

arXiv:2510.01633•Physical Review A•Dec 23, 2025•2 citations

Establishment and in-orbit test of optical link in satellite-to-ground quantum communication

Liang Zhang, Jianjun Jia, Sheng‐Kai Liao +3 more

The establishment of a high-precision optical link is a necessary condition for satellite-to-ground quantum communication experiments. Compared with conventional laser communications, a quantum experimental satellite needs to solve special requirements such as the great difference between the energy of quantum light and beacon light, and the establishment of optical links between one satellite and two ground stations. Based on the scientific demands of satellite-to-ground quantum communication, this paper proposes an overall scheme for an optical link establishing system with a combination of satellite pointing and load autonomous searching. By using a multiple-axis pointing control method, the requirements of high-precision optical tracking are met. We use the stare-stare capture method to achieve fast capture between the satellite and the ground stations. The high-precision alignment of the satellite and ground quantum beams is realized by using a method of joint scanning and system correction. Finally, in-orbit test results of the Mo-tse quantum experimental satellite are given. The experimental data show that all parameters in the establishment of optical links meet or exceed the expected requirements.

Scientia Sinica Informationis•Apr 12, 2018•5 citations

Optical front-end for a quantum key distribution cubesat

Paul C. Serra, Ondrej Čierny, William Kammerer +11 more

Recent advances in pointing and tracking capabilities of small satellite platforms have enabled adoption of capabilities such as high-resolution Earth Observation (EO), inter-satellite laser communications and, more recently, quantum communications. Quantum communications requires unusually narrow optical beams and tight pointing performance (on the order of ten microradians) to close an inherently brightness-limited quantum link. This limit is due to quantum communication protocols such as quantum key distribution and teleportation requiring individual quantum states to be transmitted with photon number restrictions. We examine an opportunity to combine quantum communications with laser communications in sharing an optical link. We discuss a combined quantum and laser communication terminal capable of performing space-to-ground entanglement-distribution and high data rate communications on a 12U CubeSat with a 95mm beam expander and an 60 cm aperture optical ground telescope. Photon pairs produced by the quantum terminal are entangled in polarization so the polarization must be maintained throughout the optical link. We discuss active and passive compensation methods in space and polarization reference frame correction using a polarized reference beacon at the ground station. The combined quantum and laser communication terminal approach enables secure communications over an optical channel with rates of 100 Mbps and sub-nanosecond time transfer.

International Conference on Space Optics (ICSO)•Jun 11, 2021•6 citations
Quantum entanglement is the main resource to endow the field of quantum information processing with powers that exceed those of classical communication and computation. Due to low absorption and negligible nonbirefringent character in atmosphere, optical free space therefore serves as the most promising channel for large-scale quantum communication by use of satellites and ground stations. The acquisition, tracking and pointing (ATP) system is one of the most important parts of quantum experiment system, and it controls a transmitting and receiving laser beam within a few micro radians jitter because of using an extremely narrow beam divergence of several micro radians. This paper introduces the cascade ATP systems for 100km quantum entanglement distribution experiment among Charlie, Bob and Alice station. The specification and optical diagram of each ATP system are presented. The ATP system of Alice station is described in detail，it has coarse, fine and ultra-fine loop. In the 100km quantum entanglement distribution experiment, a tracking error of 4μrad is achieved for 70Hz bandwidth. The ATP strategy in this experiment can be used in the prospective satellite-to-ground quantum distribution.
Acquiring,tracking and pointing(ATP) technique in a 100 km quantum entanglement distribution experiment was introduced in detail.By taking a 700 mm telescope at Alice receiving terminal as an example,the technological specification,light path layout,and tracking accuracy of the ATP system were analyzed.In order to reduce the angle-of-arrival fluctuations of quantum information transmission beams and beacon beams caused by air turbulence,a cascade acquisition and tracking system with coarse tracking,fine tracking and a ultra-fine loop was designed and a dual fast-steering mirror tracking algorithm was proposed.On the basis of a higher frame frequency CMOS detector and a piezoelectric fast-steering mirror,the ultra-fine tracking circuit was developed.Experiments show that these methods solve the contradiction between tracking dynamic range and tracking accuracy,promote the performance of the detector and improve band width and tracking accuracy.The system was used in a ground 100 km quantum entanglement distribution experiment and the results indicate that the tracking error of the system is 4 μrad for a 70 Hz bandwidth.
The development of space-based quantum communication is a critical step toward establishing global-scale secure networks. Quantum communication via satellites enables long-distance key exchange beyond the limitations of terrestrial fiber networks. To support such missions, robust optical ground stations are essential for maintaining high-fidelity quantum links with orbiting platforms. Commissioned in early 2024, the Singapore Optical Ground Station is the first dedicated facility of its kind located near the equator. Its equatorial position enables frequent access to satellites in a wide range of orbital inclinations, making it uniquely suited for supporting diverse global quantum networks. Its receiving optics can accommodate quantum links across a broad range of wavelengths and support various encoding schemes, including polarization and phase. In this work, detailed results from preliminary testing of the pointing, acquisition, and tracking system for low Earth orbit satellites are presented. For LEO satellites, a tracking accuracy reaching 50 microradians, approaching the local atmospheric seeing limit was achieved.Tracking stability is maintained using a hybrid feedback control loop designed to accommodate sporadic link losses caused by cloud cover. These results demonstrate the readiness of the SOGS to support current and future missions towards satellite quantum networks.
Designing a laser communications payload integral to a nano-satellite, capable of fine pointing, is a difficult task. Integrating this with a quantum key distribution payload for inter-satellite secure communication adds significant complexity, as does ground based communication with the moving objects in low Earth orbit. The advantages of low path length, secure, global communication make this an opportunity not to be missed. We report on developments of such a system. Beginning with a satellite demonstrator with a Pointing, Acquisition-and Tracking system that involves fine precision star-tracker, plasma and aerodynamic force interactions for steering, and an inter-satellite laser link demonstration on orbit using LED beacon for acquisition, and laser for communications link closure. Combining design studies for a nano-satellite quantum payload for transferring entangled photon-pairs between the satellites at long-range in Low Earth Orbit, and incorporating ground to space and space to ground laser communications, are described in the context of quantum optical ground station efforts within Australia.
A key technical requirement of any future quantum network is the ability to distribute quantum-entangled resources between two spatially separated points at a high rate and high fidelity. Entanglement distribution protocols based on satellite platforms, which transmit and receive quantum resources directly via free-space optical propagation, are therefore excellent candidates for quantum networking, since the geometry and loss characteristics of satellite networks feasibly allow for up to continental-scale (∼103\sim10^3∼103 km) over-the-horizon communication without the infrastructure, cost, or losses associated with equivalent fibre-optic networks. In this work, we explore two network topologies commonly associated with quantum networks - entanglement distribution between two satellites in low-Earth orbit mediated by a third satellite and entanglement distribution between two ground stations mediated by a satellite in low-Earth orbit, and two entanglement distribution schemes - one where the central satellite is used as a relay, and the other where the central satellite is used to generate and distribute the entangled resource directly. We compute a bound on the rate of distribution of distillable entanglement achieved by each protocol in each network topology as a function of the network channels for both single-rail discrete- (DV) and continuous-variable (CV) resources and use or non-use of probabilistic noiseless linear quantum amplification (NLA). In the case of atmospheric channels we take into account the turbulent and optical properties of the free-space propagation. We determine that for the triple-satellite network configuration, the optimal strategy is to perform a distributed NLA scheme in either CV or DV, and for the ground-satellite-ground network the optimal strategy is to distribute a DV resource via the central satellite.
The establishment of a high-precision optical link is a necessary condition for satellite-to-ground quantum communication experiments. Compared with conventional laser communications, a quantum experimental satellite needs to solve special requirements such as the great difference between the energy of quantum light and beacon light, and the establishment of optical links between one satellite and two ground stations. Based on the scientific demands of satellite-to-ground quantum communication, this paper proposes an overall scheme for an optical link establishing system with a combination of satellite pointing and load autonomous searching. By using a multiple-axis pointing control method, the requirements of high-precision optical tracking are met. We use the stare-stare capture method to achieve fast capture between the satellite and the ground stations. The high-precision alignment of the satellite and ground quantum beams is realized by using a method of joint scanning and system correction. Finally, in-orbit test results of the Mo-tse quantum experimental satellite are given. The experimental data show that all parameters in the establishment of optical links meet or exceed the expected requirements.
Recent advances in pointing and tracking capabilities of small satellite platforms have enabled adoption of capabilities such as high-resolution Earth Observation (EO), inter-satellite laser communications and, more recently, quantum communications. Quantum communications requires unusually narrow optical beams and tight pointing performance (on the order of ten microradians) to close an inherently brightness-limited quantum link. This limit is due to quantum communication protocols such as quantum key distribution and teleportation requiring individual quantum states to be transmitted with photon number restrictions. We examine an opportunity to combine quantum communications with laser communications in sharing an optical link. We discuss a combined quantum and laser communication terminal capable of performing space-to-ground entanglement-distribution and high data rate communications on a 12U CubeSat with a 95mm beam expander and an 60 cm aperture optical ground telescope. Photon pairs produced by the quantum terminal are entangled in polarization so the polarization must be maintained throughout the optical link. We discuss active and passive compensation methods in space and polarization reference frame correction using a polarized reference beacon at the ground station. The combined quantum and laser communication terminal approach enables secure communications over an optical channel with rates of 100 Mbps and sub-nanosecond time transfer.