Arabskyj, L; Dolan, P R; Parke, A L; Santana, T S; Hall, S R G; Porrovecchio, G; Smid, M; Lucamarini, M; Chunnilall, C J (2024) Traceable characterisation of fibre-coupled single-photon detectors. Metrologia, 61 (5). 055008

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Abstract

The detection of single-photons plays a crucial role in advancing both the science and technologies associated with single-photon applications. Yet, within the visible/near infrared (vis/NIR) region of the spectrum, accurate fibre-based optical power measurements at the few-photon level are not currently wellestablished. In this study, we report on a fibre-based setup, enabling traceable optical power measurements at the few-photon level within this spectral range. The setup was used to calibrate the detection efficiency (DE) of four single-photon avalanche diode (SPAD) detectors; absolute standard uncertainties on mean DE values ranged from 0.20% to 0.27% (k = 2). However, the standard deviations of fibre coupling repeats, being at least twice these values, pose challenges for the metrology of these devices and applications which require high accuracy and repeatability. We investigated the source of these variations by spatially mapping the response of a detector’s fibre connector port, using a focused freespace beam, allowing us to estimate the detector’s spatial non-uniformity. In addition, we realise a novel calibration approach for fibre-coupled SPADs in a free-space configuration, enabling a direct comparison between the fibre-based setup and the National Physical Laboratory’s stablished free-space facility on a single SPAD. Finally, we investigated alternative coupling methods, testing the repeatability of different fibre-to-fibre connectors in addition to direct fibre-to-detector couplings: SPADs from three manufacturers were tested, with both single-mode and multi-mode fibre.

Item Type:	Article
Subjects:	Optical Radiation and Photonics > Few Photon Science
Divisions:	Quantum Technologies
Identification number/DOI:	10.1088/1681-7575/ad70bc
Last Modified:	21 Oct 2024 13:23
URI:	https://eprintspublications.npl.co.uk/id/eprint/10082