The impact of spot‐size on single‐photon avalanche diode timing‐jitter and quantum key distribution

Abstract In free‐space implementations of Quantum key distribution (QKD), the wide adoption of near‐Infrared wavelengths has led to the common use of silicon single‐photon avalanche diodes (Si‐SPAD) for receiver systems. While the impacts of some SPAD properties on QKD have been explored extensively...

Full description

Saved in:
Bibliographic Details
Main Authors: Alexandra Lee, Alfonso Tello Castillo, Craig Whitehill, Ross Donaldson
Format: Article
Language:English
Published: Wiley 2024-12-01
Series:IET Quantum Communication
Subjects:
Online Access:https://doi.org/10.1049/qtc2.12091
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1850059974209699840
author Alexandra Lee
Alfonso Tello Castillo
Craig Whitehill
Ross Donaldson
author_facet Alexandra Lee
Alfonso Tello Castillo
Craig Whitehill
Ross Donaldson
author_sort Alexandra Lee
collection DOAJ
description Abstract In free‐space implementations of Quantum key distribution (QKD), the wide adoption of near‐Infrared wavelengths has led to the common use of silicon single‐photon avalanche diodes (Si‐SPAD) for receiver systems. While the impacts of some SPAD properties on QKD have been explored extensively, the relationship of spot‐size and spatial position on the full instrumental response and thus quantum bit error rate (QBER) has been studied little. Changes in spot size and spatial position can result from atmospheric turbulence and pointing and tracking errors. Here, An empirical analysis of that relationship is presented utilising a large active area, 500 μm, free‐space coupled Si‐SPAD designed for free‐space QKD. A baseline full‐width at half‐maximum timing jitter of 182 ps and a QBER contribution of 0.1 % for a 1 GHz clock frequency QKD system and 100 ps time‐gating window are reported. The impacts of spot‐size and spatial position can increase the QBER to over 0.3%. The link between the spot‐size and timing jitter will allow the understanding of tolerancing for the alignment of Si‐SPADs within free‐space QKD receiver systems—an important factor in designing properly engineered practical systems and the equipment needed to compensate for atmospheric turbulence and pointing and tracking.
format Article
id doaj-art-2d6cb95a8fed4fc4ab2add910c54d780
institution DOAJ
issn 2632-8925
language English
publishDate 2024-12-01
publisher Wiley
record_format Article
series IET Quantum Communication
spelling doaj-art-2d6cb95a8fed4fc4ab2add910c54d7802025-08-20T02:50:44ZengWileyIET Quantum Communication2632-89252024-12-015444344910.1049/qtc2.12091The impact of spot‐size on single‐photon avalanche diode timing‐jitter and quantum key distributionAlexandra Lee0Alfonso Tello Castillo1Craig Whitehill2Ross Donaldson3Wideblue Ltd Glasgow UKInstitute of Photonics & Quantum Sciences School of Engineering and Physical Sciences Heriot‐Watt University Edinburgh UKWideblue Ltd Glasgow UKInstitute of Photonics & Quantum Sciences School of Engineering and Physical Sciences Heriot‐Watt University Edinburgh UKAbstract In free‐space implementations of Quantum key distribution (QKD), the wide adoption of near‐Infrared wavelengths has led to the common use of silicon single‐photon avalanche diodes (Si‐SPAD) for receiver systems. While the impacts of some SPAD properties on QKD have been explored extensively, the relationship of spot‐size and spatial position on the full instrumental response and thus quantum bit error rate (QBER) has been studied little. Changes in spot size and spatial position can result from atmospheric turbulence and pointing and tracking errors. Here, An empirical analysis of that relationship is presented utilising a large active area, 500 μm, free‐space coupled Si‐SPAD designed for free‐space QKD. A baseline full‐width at half‐maximum timing jitter of 182 ps and a QBER contribution of 0.1 % for a 1 GHz clock frequency QKD system and 100 ps time‐gating window are reported. The impacts of spot‐size and spatial position can increase the QBER to over 0.3%. The link between the spot‐size and timing jitter will allow the understanding of tolerancing for the alignment of Si‐SPADs within free‐space QKD receiver systems—an important factor in designing properly engineered practical systems and the equipment needed to compensate for atmospheric turbulence and pointing and tracking.https://doi.org/10.1049/qtc2.12091optical fibre networksphotonsquantum communication
spellingShingle Alexandra Lee
Alfonso Tello Castillo
Craig Whitehill
Ross Donaldson
The impact of spot‐size on single‐photon avalanche diode timing‐jitter and quantum key distribution
IET Quantum Communication
optical fibre networks
photons
quantum communication
title The impact of spot‐size on single‐photon avalanche diode timing‐jitter and quantum key distribution
title_full The impact of spot‐size on single‐photon avalanche diode timing‐jitter and quantum key distribution
title_fullStr The impact of spot‐size on single‐photon avalanche diode timing‐jitter and quantum key distribution
title_full_unstemmed The impact of spot‐size on single‐photon avalanche diode timing‐jitter and quantum key distribution
title_short The impact of spot‐size on single‐photon avalanche diode timing‐jitter and quantum key distribution
title_sort impact of spot size on single photon avalanche diode timing jitter and quantum key distribution
topic optical fibre networks
photons
quantum communication
url https://doi.org/10.1049/qtc2.12091
work_keys_str_mv AT alexandralee theimpactofspotsizeonsinglephotonavalanchediodetimingjitterandquantumkeydistribution
AT alfonsotellocastillo theimpactofspotsizeonsinglephotonavalanchediodetimingjitterandquantumkeydistribution
AT craigwhitehill theimpactofspotsizeonsinglephotonavalanchediodetimingjitterandquantumkeydistribution
AT rossdonaldson theimpactofspotsizeonsinglephotonavalanchediodetimingjitterandquantumkeydistribution
AT alexandralee impactofspotsizeonsinglephotonavalanchediodetimingjitterandquantumkeydistribution
AT alfonsotellocastillo impactofspotsizeonsinglephotonavalanchediodetimingjitterandquantumkeydistribution
AT craigwhitehill impactofspotsizeonsinglephotonavalanchediodetimingjitterandquantumkeydistribution
AT rossdonaldson impactofspotsizeonsinglephotonavalanchediodetimingjitterandquantumkeydistribution