Design and test of optical payload for polarization encoded QKD for nanosatellites

Sagar, Jaya; Hastings, Elliot; Zhang, Peide; Stefko, Milan; Lowndes, David; Oi, Daniel K. L.; Rarity, John; Joshi, Siddarth Koduru

doi:10.1117/12.2645103

Cited by 3 publications

(1 citation statement)

References 14 publications

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“…Pathfinder missions are exploring the use of dual sources. 43 For the case of two different wavelength operations, we can estimate the key length. For the case of λ = 785 nm and λ = 850 nm, we assume that we can take finite blocks by combining them to generate a secure key.…”

Section: Ogs Site Comparisonmentioning

confidence: 99%

Satellite quantum key distribution performance analysis and optimization with finite key size constraints

Sidhu¹,

Brougham²,

McArthur³

et al. 2023

Quantum Computing, Communication, and Simulation III

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Quantum Key Distribution (QKD) is a potential mitigation against quantum computation advances that threaten currently deployed public key cryptosystems. QKD is also a precursor to large-scale quantum communications and the quantum internet. Terrestrial direct transmission of quantum photonic signals is restricted by optical fibre exponential absorption, hence space-based systems have been proposed for intercontinental distribution of quantum keys with lower-loss free-space transmission through vacuum. However, challenges remain for the practical deployment of satellite QKD (SatQKD) such as weather, background light, and terminal deployment. In particular, the short transmission time inherent in low Earth orbit satellite QKD and finite statistical uncertainty can limit secure key generation. Here we illustrate the analysis of these effects and some practical engineering design and operational constraints on key length using the Satellite Quantum Modelling and Analysis (SatQuMA) software package being developed for satellite quantum communications research.

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Section: Ogs Site Comparisonmentioning

confidence: 99%

Satellite quantum key distribution performance analysis and optimization with finite key size constraints

Sidhu¹,

Brougham²,

McArthur³

et al. 2023

Quantum Computing, Communication, and Simulation III

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End‐to‐end demonstration for CubeSatellite quantum key distribution

Zhang,

Sagar,

Hastings

et al. 2024

IET Quantum Communication

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Quantum key distribution (QKD) provides a method of ensuring security using the laws of physics, avoiding the risks inherent in cryptosystems protected by computational complexity. Here, the authors investigate the feasibility of satellite‐based quantum key exchange using low‐cost compact nano‐satellites. The first prototype of system level quantum key distribution aimed at the Cube satellite scenario is demonstrated. It consists of a transmitter payload, a ground receiver and simulated free space channel to verify the timing and synchronisation (T&S) scheme designed for QKD and the required high loss tolerance of both QKD and T&S channels. The transmitter is designed to be deployed on various up‐coming nano‐satellite missions in the UK and internationally. The effects of channel loss, background noise, gate width and mean photon number on the secure key rate (SKR) and quantum bit error rate (QBER) are discussed. The authors also analyse the source of QBER and establish the relationship between effective signal noise ratio (ESNR) and noise level, signal strength, gating window and other parameters as a reference for SKR optimisation. The experiment shows that it can tolerate the 40 dB loss expected in space to ground QKD and with small adjustment decoy states can be achieved. The discussion offers valuable insight not only for the design and optimisation of miniature low‐cost satellite‐based QKD systems but also any other short or long range free space QKD on the ground or in the air.

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Multicore fiber beacon system for reducing back-reflection in satellite quantum key distribution

Simmons¹,

Donaldson²

2023

Opt. Express

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Optical beaconing is an important part of the acquisition, pointing and tracking system necessary for free-space quantum key distribution (QKD). However, uplink beacon back-reflections from the receiver architecture can result in noise. Wavelength- and time-division multiplexing has been used, but neither is yet sufficient to make back-reflection negligible. The use of additional telescopes increases complexity and pointing error. Here, we propose the use of a 2-by-2 multicore fiber, to act as an optical uplink beacon source. This spatially separates the QKD channel and optical uplink beacon. Up to 50 dB improvement in noise rejection over a purely spectrally divided system was demonstrated. The route to further improvements through greater fiber core separation is described. Beacon systems designed in this way could provide a combination of reduced complexity and improved noise performance to free-space and satellite QKD and optical communications.

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Design and test of optical payload for polarization encoded QKD for nanosatellites

Cited by 3 publications

References 14 publications

Satellite quantum key distribution performance analysis and optimization with finite key size constraints

Satellite quantum key distribution performance analysis and optimization with finite key size constraints

End‐to‐end demonstration for CubeSatellite quantum key distribution

Multicore fiber beacon system for reducing back-reflection in satellite quantum key distribution

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