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:1406.3953 · IEEE Transactions on Nuclear Science

A Compact Readout Electronics for the Ground Station of a Quantum Communication Satellite

B. Qi, Shubin Liu, Qi Shen, Sheng‐Kai Liao, Wenqi Cai, Zehong Lin, Wei-Yue Liu, Cheng-Zhi Peng, Qi An

Published Jun 1, 2015• 6 citations
arXivHTMLPDF

Abstract

Free-space quantum key distribution (QKD) is being developed for achieving unconditional secure communication over ultra-long distance, which requires higher electronics performance, such as higher time measurement precision, higher data-transfer rate, and higher system integration density. As part of the ground station of the Quantum Science Satellite that will be launched in 2016, we specifically designed a compact PCI-based measurement and control electronics with high time-resolution and high data-transfer-rate. Some necessary modules in the quantum communication experiment such as multi-channel counter, system monitor and experiment control are also integrated in a single board. The electronics performance of this system was tested, with the time precision bin size is 23.9 ps and the time resolution root-mean-square (RMS) is less than 24 ps for 16 channels. The dead time is 30 ns. The data transfer rate to a local computer is up to 35 MBps, and the count rate is up to 30 MHz. The system has been proven to perform well and operate stably through a test of in-door free space QKD experiment.

DOI
10.1109/tns.2015.2435019

Related papers

An FPGA-Based TDC for Free Space Quantum Key Distribution

Qi Shen, Sheng‐Kai Liao, Shubin Liu +4 more

Quantum key distribution (QKD) is the most matured application of quantum communication. The time synchronization and system timing jitter are essential to a practical QKD experiment, which can directly influence the quantum bit error rate (QBER) and the final key rate. High precision time-to-digital converters (TDCs) can effectively reduce the system timing jitter, resulting in lower QBER and higher key rate. Here, we introduce a TDC based on a field programmable gate array (FPGA). Its high resolution (LSB) of 50 ps with precision (RMS) less than 50 ps, low dead time and large dynamic range can well meet the requirement of the QKD experiment. A free space QKD system setup using the FPGA-based TDC has been assembled. The timing precision of the synchronous light and the system timing jitter were determined. The results demonstrate that the FPGA-based TDC could be successfully applied in the QKD experiment.

IEEE Transactions on Nuclear Science•Oct 1, 2013•25 citations

Satellite QKD developments for secure communications

Agnes Ferenczi, Stefanie Häusler, Davide Orsucci +2 more

Quantum key distribution (QKD), the technology to generate distant secure keys for later usage in secure communication, has become a mature topic since the 1980s. While terrestrial QKD over fiber networks is suitable for short-distance urban networks, QKD via satellites promises to gap the distance requirement on a global scale that limits terrestrial QKD. Satellite QKD requires the exchange of quantum states between a satellite and multiple ground stations. The goal is then to facilitate shared secret keys between the ground stations, which can then be relayed to users near the ground stations. The satellite usually carries the quantum sources as its payload and sends them to the ground station via a downlink. The QKD protocol is heavily influenced by the choice of the quantum source, with typically one of two types: approximate single photon source (such as a weak laser) or an entangled source. Similarly, the ground station must be equipped to receive, measure and process the quantum signals sent by the satellite. Although there are also reverse schemes, where the satellite acts as the receiver and the ground station as the sender, these schemes are less explored due to higher noise in the uplink and less engineering experience. As with any system containing a high heterogeneity, many different implementation schemes lead to a variety of optimized use cases based on different criteria. Satellite QKD carries the further complication that it must be adapted to international standards. In this paper we present different satellite and ground station architectures that lean on the developments in the projects EAGLE-1, QUBE, QuNET, RoGloQuaN, addressing different protocols, sources, satellite sizes and telescope sizes. We also discuss the need for agility and configuration of components in a heterogeneous environment.

SPIE Quantum Technologies for Defence and Security•Oct 29, 2025•1 citation

7 km free-space time-bin quantum key distribution

Bo-Yang Qiu, Yang Li, Gao‐Qiang Wang +14 more

Satellite-based quantum key distribution (QKD) holds the potential to establish global quantum communication networks. While satellite QKD has been demonstrated using polarization encoding, time-bin encoding offers distinct advantages, such as simplifying polarization-maintaining telescope designs and being insensitive to satellite-ground relative motion. In this work, we developed a 625-MHz QKD light source using a robust Sagnac-interferometer-based modulation scheme and subsequently demonstrated time-bin QKD over a 7 km urban terrestrial free-space channel. This experiment successfully operated over a channel traversing an equivalent atmospheric thickness and loss exceeding that of typical satellite-to-ground links, achieving a low quantum bit error rate of 0.87% and a secure key rate of 134 bps@51.4 dB. Furthermore, by using a half-wave plate to simulate the polarization-basis-rotation inherent in such links, we verified the robustness of time-bin encoding for satellite scenarios. The results validate time-bin encoding as a compelling alternative and lay the technical foundation for future satellite QKD applications.

Optics Express•Jul 29, 2025•4 citations

Experimental free-space quantum key distribution with efficient error correction

Wei-Yue Liu, Xian-Feng Zhong, Teng Wu +10 more

We report a 17-km free-space quantum key distribution (QKD) experiment using an engineering model of the space-bound optical transmitter and a ground station for satellite-ground QKD. The final key rate of ~ 0.5 kbps is achieved in this experiment with the quantum bit error rate (QBER) of ~ 3.4%. An efficient error correction algorithm, Turbo Code, is employed. Compared with the current error correction algorithm of Cascade, a high-efficiency error correction is realized by Turbo Code with only one-time data exchange. For a low QBER, with only one-time data exchange, the final key rates based on Turbo code are similar with Cascade. As the QBER increases, Turbo Code gives higher final key rates than Cascade. Our results experimentally demonstrate the feasibility of satellite-ground QKD and show that the efficient error correction based on Turbo Code is potentially useful for the satellite-ground quantum communication.

Optics Express•May 1, 2017•15 citations

Aerospace laser communications technology as enabler for worldwide quantum key distribution

Florian Moll, Harald Weinfurter, Markus Rau +5 more

A worldwide growing interest in fast and secure data communications pushes technology development along two lines. While fast communications can be realized using laser communications in fiber and free-space, inherently secure communications can be achieved using quantum key distribution (QKD). By combining both technologies in a single device, many synergies can be exploited, therefore reducing size, weight and power of future systems. In recent experiments we demonstrated quantum communications over large distances as well as between an aircraft and a ground station which proved the feasibility of QKD between moving partners. Satellites thus may be used as trusted nodes in combination with QKD receiver stations on ground, thereby enabling fast and secure communications on a global scale. We discuss the previous experiment with emphasis on necessary developments to be done and corresponding ongoing research work of German Aerospace Center (DLR) and Ludwig Maximilians University Munich (LMU). DLR is performing research on satellite and ground terminals for the high-rate laser communication component, which are enabling technologies for the QKD link. We describe the concept and hardware of three generations of OSIRIS (Optical High Speed Infrared Link System) laser communication terminals for low Earth orbiting satellites. The first type applies laser beam pointing solely based on classical satellite control, the second uses an optical feedback to the satellite bus and the third, currently being in design phase, comprises of a special coarse pointing assembly to control beam direction independent of satellite orientation. Ongoing work also targets optical terminals for CubeSats. A further increase of beam pointing accuracy can be achieved with a fine pointing assembly. Two ground stations will be available for future testing, an advanced stationary ground station and a transportable ground station. In parallel the LMU QKD source size will be reduced by more than an order of magnitude thereby simplifying its integration into future free-space optical communication links with CubeSats.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Apr 29, 2016•8 citations

High-Rate Quantum Key Distribution Over Free-Space Links

Thomas Roger, Ravinder Singh, Chithrabhanu Perumangatt +4 more

To enable practical real-time quantum key distribution (QKD) over free-space links, such as for satellite-to-ground secure communications, the encoding rate of the system should be sufficiently high to distribute long keys (>106bits) in a short period of time (< 300 seconds) [1]. Here, we report an optical assembly and driving electronics designed to form a low-size}, weight and power (SWaP) QKD transmitter, which can operate at gigahertz clock rates. The QKD transmitter employs multiple vertical cavity surface emission lasers (VCSELs), which provide a low power and high polarization extinction ratio (PER) source of weak coherent pulses of light. These light pulses are combined using an intrinsically stable optical combining module utilising polarization-maintaining fiber. In the experiments presented we employ discrete variable QKD via the decoy-state BB84 protocol to achieve high secure key rates over large channel losses [2]. We characterise the source using a free-space polarization decoder over short free-space links within the laboratory and explore the performance of the system with commercially available single photon detectors. Fig. 1 Plot showing the effect of varying the channel loss over the free-space link. We show the measured quantum bit error rate (blue circles), sifting rate (green triangles) and secure key rate (red squares) alongside the rates simulated using the measured system parameters (solid lines). We characterise the system up to ~38 db of channel loss, revealing positive key rates at relatively high channel loss.

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)•Jun 26, 2023•0 citations
Free-space quantum key distribution (QKD) is being developed for achieving unconditional secure communication over ultra-long distance, which requires higher electronics performance, such as higher time measurement precision, higher data-transfer rate, and higher system integration density. As part of the ground station of the Quantum Science Satellite that will be launched in 2016, we specifically designed a compact PCI-based measurement and control electronics with high time-resolution and high data-transfer-rate. Some necessary modules in the quantum communication experiment such as multi-channel counter, system monitor and experiment control are also integrated in a single board. The electronics performance of this system was tested, with the time precision bin size is 23.9 ps and the time resolution root-mean-square (RMS) is less than 24 ps for 16 channels. The dead time is 30 ns. The data transfer rate to a local computer is up to 35 MBps, and the count rate is up to 30 MHz. The system has been proven to perform well and operate stably through a test of in-door free space QKD experiment.
Quantum key distribution (QKD) is the most matured application of quantum communication. The time synchronization and system timing jitter are essential to a practical QKD experiment, which can directly influence the quantum bit error rate (QBER) and the final key rate. High precision time-to-digital converters (TDCs) can effectively reduce the system timing jitter, resulting in lower QBER and higher key rate. Here, we introduce a TDC based on a field programmable gate array (FPGA). Its high resolution (LSB) of 50 ps with precision (RMS) less than 50 ps, low dead time and large dynamic range can well meet the requirement of the QKD experiment. A free space QKD system setup using the FPGA-based TDC has been assembled. The timing precision of the synchronous light and the system timing jitter were determined. The results demonstrate that the FPGA-based TDC could be successfully applied in the QKD experiment.
Quantum key distribution (QKD), the technology to generate distant secure keys for later usage in secure communication, has become a mature topic since the 1980s. While terrestrial QKD over fiber networks is suitable for short-distance urban networks, QKD via satellites promises to gap the distance requirement on a global scale that limits terrestrial QKD. Satellite QKD requires the exchange of quantum states between a satellite and multiple ground stations. The goal is then to facilitate shared secret keys between the ground stations, which can then be relayed to users near the ground stations. The satellite usually carries the quantum sources as its payload and sends them to the ground station via a downlink. The QKD protocol is heavily influenced by the choice of the quantum source, with typically one of two types: approximate single photon source (such as a weak laser) or an entangled source. Similarly, the ground station must be equipped to receive, measure and process the quantum signals sent by the satellite. Although there are also reverse schemes, where the satellite acts as the receiver and the ground station as the sender, these schemes are less explored due to higher noise in the uplink and less engineering experience. As with any system containing a high heterogeneity, many different implementation schemes lead to a variety of optimized use cases based on different criteria. Satellite QKD carries the further complication that it must be adapted to international standards. In this paper we present different satellite and ground station architectures that lean on the developments in the projects EAGLE-1, QUBE, QuNET, RoGloQuaN, addressing different protocols, sources, satellite sizes and telescope sizes. We also discuss the need for agility and configuration of components in a heterogeneous environment.
Satellite-based quantum key distribution (QKD) holds the potential to establish global quantum communication networks. While satellite QKD has been demonstrated using polarization encoding, time-bin encoding offers distinct advantages, such as simplifying polarization-maintaining telescope designs and being insensitive to satellite-ground relative motion. In this work, we developed a 625-MHz QKD light source using a robust Sagnac-interferometer-based modulation scheme and subsequently demonstrated time-bin QKD over a 7 km urban terrestrial free-space channel. This experiment successfully operated over a channel traversing an equivalent atmospheric thickness and loss exceeding that of typical satellite-to-ground links, achieving a low quantum bit error rate of 0.87% and a secure key rate of 134 bps@51.4 dB. Furthermore, by using a half-wave plate to simulate the polarization-basis-rotation inherent in such links, we verified the robustness of time-bin encoding for satellite scenarios. The results validate time-bin encoding as a compelling alternative and lay the technical foundation for future satellite QKD applications.
We report a 17-km free-space quantum key distribution (QKD) experiment using an engineering model of the space-bound optical transmitter and a ground station for satellite-ground QKD. The final key rate of ~ 0.5 kbps is achieved in this experiment with the quantum bit error rate (QBER) of ~ 3.4%. An efficient error correction algorithm, Turbo Code, is employed. Compared with the current error correction algorithm of Cascade, a high-efficiency error correction is realized by Turbo Code with only one-time data exchange. For a low QBER, with only one-time data exchange, the final key rates based on Turbo code are similar with Cascade. As the QBER increases, Turbo Code gives higher final key rates than Cascade. Our results experimentally demonstrate the feasibility of satellite-ground QKD and show that the efficient error correction based on Turbo Code is potentially useful for the satellite-ground quantum communication.
A worldwide growing interest in fast and secure data communications pushes technology development along two lines. While fast communications can be realized using laser communications in fiber and free-space, inherently secure communications can be achieved using quantum key distribution (QKD). By combining both technologies in a single device, many synergies can be exploited, therefore reducing size, weight and power of future systems. In recent experiments we demonstrated quantum communications over large distances as well as between an aircraft and a ground station which proved the feasibility of QKD between moving partners. Satellites thus may be used as trusted nodes in combination with QKD receiver stations on ground, thereby enabling fast and secure communications on a global scale. We discuss the previous experiment with emphasis on necessary developments to be done and corresponding ongoing research work of German Aerospace Center (DLR) and Ludwig Maximilians University Munich (LMU). DLR is performing research on satellite and ground terminals for the high-rate laser communication component, which are enabling technologies for the QKD link. We describe the concept and hardware of three generations of OSIRIS (Optical High Speed Infrared Link System) laser communication terminals for low Earth orbiting satellites. The first type applies laser beam pointing solely based on classical satellite control, the second uses an optical feedback to the satellite bus and the third, currently being in design phase, comprises of a special coarse pointing assembly to control beam direction independent of satellite orientation. Ongoing work also targets optical terminals for CubeSats. A further increase of beam pointing accuracy can be achieved with a fine pointing assembly. Two ground stations will be available for future testing, an advanced stationary ground station and a transportable ground station. In parallel the LMU QKD source size will be reduced by more than an order of magnitude thereby simplifying its integration into future free-space optical communication links with CubeSats.
To enable practical real-time quantum key distribution (QKD) over free-space links, such as for satellite-to-ground secure communications, the encoding rate of the system should be sufficiently high to distribute long keys (>106bits) in a short period of time (< 300 seconds) [1]. Here, we report an optical assembly and driving electronics designed to form a low-size}, weight and power (SWaP) QKD transmitter, which can operate at gigahertz clock rates. The QKD transmitter employs multiple vertical cavity surface emission lasers (VCSELs), which provide a low power and high polarization extinction ratio (PER) source of weak coherent pulses of light. These light pulses are combined using an intrinsically stable optical combining module utilising polarization-maintaining fiber. In the experiments presented we employ discrete variable QKD via the decoy-state BB84 protocol to achieve high secure key rates over large channel losses [2]. We characterise the source using a free-space polarization decoder over short free-space links within the laboratory and explore the performance of the system with commercially available single photon detectors. Fig. 1 Plot showing the effect of varying the channel loss over the free-space link. We show the measured quantum bit error rate (blue circles), sifting rate (green triangles) and secure key rate (red squares) alongside the rates simulated using the measured system parameters (solid lines). We characterise the system up to ~38 db of channel loss, revealing positive key rates at relatively high channel loss.