Entanglement demonstration on board a nano-satellite

Villar, Aitor; Lohrmann, Alexander; Bai, Xueliang; Vergoossen, Tom; Bedington, Robert; Perumangatt, Chithrabhanu; Lim, Huai Ying; Islam, Tanvirul; Reezwana, Ayesha; Tang, Zhongkan; Chandrasekara, Rakhitha; Sachidananda, Subash; Durak, Kadir; Wildfeuer, Christoph F.; Griffin, Douglas; Oi, Daniel K. L.; Ling, Alexander

doi:10.1364/optica.387306

Cited by 93 publications

(73 citation statements)

References 33 publications

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“…There are several atmospheric transparency windows in the near infrared and short-wave (telecommunication) infrared regions that are usually considered due to the availability and performance of sources, detectors and optical components operating at these wavelengths [316]. The performance of the various QKD components at the chosen wavelength must also be F I G U R E 8 In-orbit temperature fluctuations of SpooQy-1 [217]. This 3U CubeSat was deployed from the ISS (400 km altitude) in 2019 and orbited the Earth every 90 min (5400 s).…”

Section: Optical Link Configurationmentioning

confidence: 99%

Advances in space quantum communications

Sidhu

Joshi

Gündoğan

et al. 2021

IET Quantum Communication

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155

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Concerted efforts are underway to establish an infrastructure for a global quantum Internet to realise a spectrum of quantum technologies. This will enable more precise sensors, secure communications, and faster data processing. Quantum communications are a front-runner with quantum networks already implemented in several metropolitan areas. A number of recent proposals have modelled the use of space segments to overcome range limitations of purely terrestrial networks. Rapid progress in the design of quantum devices have enabled their deployment in space for in-orbit demonstrations. We review developments in this emerging area of space-based quantum technologies and provide a roadmap of key milestones towards a complete, global quantum networked landscape. Small satellites hold increasing promise to provide a cost effective coverage required to realise the quantum Internet. The state of art in small satellite missions is reviewed and the most current in-field demonstrations of quantum cryptography are collated. The important challenges in space quantum technologies that must be overcome and recent efforts to mitigate their effects are summarised. A perspective on future developments that would improve the performance of space quantum communications is included. The authors conclude with a discussion on fundamental physics experiments that could take advantage of a global, space-based quantum network.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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Section: Optical Link Configurationmentioning

confidence: 99%

Advances in space quantum communications

Sidhu

Joshi

Gündoğan

et al. 2021

IET Quantum Communication

Self Cite

155

View full text Add to dashboard Cite

show abstract

“…One of the important applications of QKD is in the extra-terrestrial channels, which potentially allow extremely long-distance secure communication enabled by QKD over a satellite. While discrete-variable protocols were recently successfully tested over the satellite links [ 6 , 7 , 8 , 9 ], the applicability of satellite-based CV QKD remains less studied. Indeed, it was considered in the asymptotic regime of the infinitely many quantum states [ 10 , 11 ], which however is never the case in practice.…”

Section: Introductionmentioning

confidence: 99%

Applicability of Squeezed- and Coherent-State Continuous-Variable Quantum Key Distribution over Satellite Links

Derkach

Usenko

2020

Entropy

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We address the applicability of quantum key distribution with continuous-variable coherent and squeezed states over long-distance satellite-based links, considering low Earth orbits and taking into account strong varying channel attenuation, atmospheric turbulence and finite data ensemble size effects. We obtain tight security bounds on the untrusted excess noise on the channel output, which suggest that substantial efforts aimed at setup stabilization and reduction of noise and loss are required, or the protocols can be realistically implemented over satellite links once either individual or passive collective attacks are assumed. Furthermore, splitting the satellite pass into discrete segments and extracting the key from each rather than from the overall single pass allows one to effectively improve robustness against the untrusted channel noise and establish a secure key under active collective attacks. We show that feasible amounts of optimized signal squeezing can substantially improve the applicability of the protocols allowing for lower system clock rates and aperture sizes and resulting in higher robustness against channel attenuation and noise compared to the coherent-state protocol.

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“…Entanglement has emerged as an essential concept and tool for practical quantum technologies including quantum computation, communication and sensing [8][9][10]. The engineering of entangled photon sources reached to such a high level that they are shown to survive through a rocket explosion, squeezed into a CubeSat and even perform intercontinental quantum key distribution (QKD) [11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Optimization of collection optics for maximum fidelity in entangled photon sources

Durak¹

2020

Turk J Phys

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In this report the decoherence sources for entangled photons created by spontaneous parametric down conversion phenomenon is studied. The phase and spatial distinguishability of photon pairs from orthogonal crystals reduce the maximum achievable entanglement fidelity. Carefully chosen compensation crystals are used to erase the phase and spatial traces of down conversion origins. Emission angle of photon pairs also leads to optical path difference and resulting in phase distinguishability. A realistic scenario is numerically modelled, where the photon pairs with nonzero emission angle gather a phase difference. These pairs can still be collected and manipulated for practical use but the collection optics adds upon the phase difference. Two commercially available optics for collection; aspheric and achromatic lenses are compared. The numerical simulation results are compared with the experimental results to validate the built model for predicting the maximum achievable entanglement fidelity. The results indicate that the fidelity can be accurately estimated with the presented model by inserting the experimental parameters to it. The study is expected to be very useful for preparation and optimization of entangled photon pair sources in critical phase-matching configuration.

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Entanglement demonstration on board a nano-satellite

Cited by 93 publications

References 33 publications

Advances in space quantum communications

Advances in space quantum communications

Applicability of Squeezed- and Coherent-State Continuous-Variable Quantum Key Distribution over Satellite Links

Optimization of collection optics for maximum fidelity in entangled photon sources

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