The avalanche delay effect in sine-gated single-photon detector based on InGaAs/InP SPADs

TL;DR

This paper investigates the avalanche delay effect in sine-gated InGaAs/InP SPADs used for quantum key distribution, revealing its nature, causes, and how control parameters influence it, impacting system error rates.

Contribution

It identifies and characterizes the avalanche delay effect in sine-gated SPADs, a phenomenon not related to known effects, and examines how control parameters affect it.

Findings

Avalanche delay occurs at the next gate after photon detection.

The effect is independent of afterpulsing and charge persistence.

Temperature, gate amplitude, and threshold voltage influence the avalanche delay.

Abstract

A sine-gated single-photon detector (SPD) intended for use in a quantum key distribution (QKD) system is considered in this paper. An "avalanche delay" effect in the sine-gated SPD is revealed. This effect consists in the appearance of an avalanche triggered at the next gate after the photon arrival gate. It has been determined experimentally that the nature of this effect is not related to the known effects of afterpulsing or charge persistence. This effect negatively affects the overall error rate in the QKD system. The influence of the main detector control parameters, such as temperature, gate amplitude and comparator's threshold voltage, on the avalanche delay effect was experimentally established.