Derivation of sensitivity of a Geiger mode APDs detector from a given efficiency for QKD experiments

TL;DR

This paper estimates the detection sensitivity of a commercial InGaAs APD used in QKD, accounting for digital blanking effects, and provides a method to relate sensitivity to overall detection efficiency.

Contribution

It introduces a numerical simulation approach to derive the sensitivity of Geiger mode APDs considering digital blanking, aiding in better efficiency estimation for QKD systems.

Findings

Average blanked pulses following a registered pulse is 0.333

Detection sensitivity is estimated at 0.216

Method to estimate overall detection efficiency from sensitivity

Abstract

The detection sensitivity (DS) of the commercial single-photon-receiver based on InGaAs gate-mode avalanche photodiode is estimated. Instalment of a digital-blanking-system (DBS) to reduce dark current makes the difference between DS, which is an efficiency of the detector during its open-gate/active state, and the total/overall detection efficiency (DE). By numerical simulations, it is found that the average number of light-pulses, blanked by DBS, following a registered pulse is 0.333. DS is estimated at 0.216, which can be used for estimating DE for an arbitrary photon arriving rate and a gating frequency of the receiver.