Abstract
To better understand how the active hold-off technique in single-photon detectors (SPDs) based on InGaAs/InP avalanche photodiodes (APDs) enhances the performance of a quantum key distribution (QKD) system based on the BB84 protocol, we have evaluated the dependence of the raw key creation rate (
R
raw) as well as the quantum bit error rate (QBER) on the number of active hold-off gates. The results of our analysis reveal that at 10 MHz repetition rate of the gate, by holding-off 200 gate pulses immediately following an avalanche event, the afterpulse contribution to the QBER drops down to 2.35% without noticeable decrease in the
R
raw.
► We evaluate the effect of the active hold-off technique on the
R
raw as well as the QBER. ► This technique significantly reduces the afterpulse contribution to the QBER. ► The
R
raw does not decrease a lot by holding-off some gate pulses. ► The repetition rate of the detector can easily reach GHz using the active hold-off technique.