Improving photon number resolvability of a superconducting nanowire detector array using a level comparator circuit

TL;DR

This paper demonstrates a 16-element superconducting nanowire detector array with a level comparator circuit that significantly improves photon number resolution and reduces timing jitter, advancing quantum optical detection capabilities.

Contribution

The study introduces a level comparator circuit to enhance the SNR and PNR resolution of a superconducting nanowire detector array, addressing electronic noise limitations.

Findings

SNRPNR improved over four times with LCC

PNR resolution effectively enhanced by LCC

Timing jitter reduced from 90 ps to 72 ps

Abstract

Photon number resolving (PNR) capability is very important in many optical applications, including quantum information processing, fluorescence detection, and few-photon-level ranging and imaging. Superconducting nanowire single-photon detectors (SNSPDs) with a multipixel interleaved architecture give the array an excellent spatial PNR capability. However, the signal-to-noise ratio (SNR) of the photon number resolution (SNRPNR) of the array will be degraded with increasing the element number due to the electronic noise in the readout circuit, which limits the PNR resolution as well as the maximum PNR number. In this study, a 16-element interleaved SNSPD array was fabricated, and the PNR capability of the array was investigated and analyzed. By introducing a level comparator circuit (LCC), the SNRPNR of the detector array was improved over a factor of four. In addition, we performed a statistical analysis of the photon number on this SNSPD array with LCC, showing that the LCC method effectively enhances the PNR resolution. Besides, the system timing jitter of the detector was reduced from 90 ps to 72 ps due to the improved electrical SNR.