Metrological evaluation of the influence of the detection gate width on a single photon detector through optical attenuation

Abstract

In this paper, we propose a method for evaluating the impact of the detection gate width of an InGaAs/InP single-photon avalanche diode detector by analyzing the probability of detecting 0 or 1 photon as a function of the optical attenuation and the consequent variation of the average number of photons per gate measured by the detector (μ¯). With a detection efficiency η of 15 % and a dead time of 1 µs, considering gate widths of 4 ns, 8 ns, 12 ns, 16 ns, and 20 ns, an adequate optical power range for calibrating a single-photon avalanche diode detector was obtained in the range of 0.15 nW to 10 nW, with linear behavior and low measurement uncertainty of calibration curve fittings for 4 ns and 8 ns gate widths, respectively, associated with products μ¯η of 0.32 × 10-4 to 190 × 10-4 and 2.90 × 10-4 to 140 × 10-4.