Time-walk and jitter correction in SNSPDs at high count rates

TL;DR

This paper presents a calibration and software correction method for superconducting nanowire single-photon detectors that significantly reduces timing jitter at high count rates, enabling faster quantum communication protocols.

Contribution

The authors introduce a novel calibration technique that correlates detection delays with pulse intervals, effectively reducing high-rate jitter in SNSPDs through software correction.

Findings

Reduced jitter by 45% at 11.4 million counts per second

Effectively removes long tail in instrument response at high rates

Enables quantum communication protocols to operate nearly twice as fast

Abstract

Superconducting nanowire single-photon detectors (SNSPDs) are a leading detector type for time correlated single photon counting, especially in the near-infrared. When operated at high count rates, SNSPDs exhibit increased timing jitter caused by internal device properties and features of the RF amplification chain. Variations in RF pulse height and shape lead to variations in the latency of timing measurements. To compensate for this, we demonstrate a calibration method that correlates delays in detection events with the time elapsed between pulses. The increase in jitter at high rates can be largely canceled in software by applying corrections derived from the calibration process. We demonstrate our method with a single-pixel tungsten silicide SNSPD and show it decreases high count rate jitter. The technique is especially effective at removing a long tail that appears in the instrument response function at high count rates. At a count rate of 11.4 MCounts/s we reduce the full width at one percent maximum level (FW1%M) by 45%. The method therefore enables certain quantum communication protocols that are rate-limited by the (FW1%M) metric to operate almost twice as fast. \c{opyright} 2022. All rights reserved.