Calibration of free-space and fiber-coupled single-photon detectors

TL;DR

This paper presents precise calibration methods for single-photon detectors at specific wavelengths, comparing free-space and fiber-coupled types, with detailed uncertainty analysis and efficiency corrections.

Contribution

It provides a comprehensive calibration approach including uncertainty analysis and efficiency corrections for free-space and fiber-coupled single-photon detectors.

Findings

Detection efficiency uncertainty as low as 0.70% at 1533.6 nm

Spatial uniformity of free-space detectors characterized

Comparison between fusion-spliced and connectorized fiber-coupled detectors

Abstract

We measure the detection efficiency of single-photon detectors at wavelengths near 851 nm and 1533.6 nm. We investigate the spatial uniformity of one free-space-coupled single-photon avalanche diode and present a comparison between fusion-spliced and connectorized fiber-coupled single-photon detectors. We find that our expanded relative uncertainty for a single measurement of the detection efficiency is as low as 0.70 % for fiber-coupled measurements at 1533.6 nm and as high as 1.78 % for our free-space characterization at 851.7 nm. The detection-efficiency determination includes corrections for afterpulsing, dark count, and count-rate effects of the single-photon detector with the detection efficiency interpolated to operation at a specified detected count rate.