Scalable readout interface for superconducting nanowire single-photon detectors using AQFP and RSFQ logic families.

Naoki Takeuchi,Fumihiro China,Shigeyuki Miyajima,Nobuyuki Yoshikawa,Hirotaka Terai,Shigehito Miki,Masahiro Yabuno

doi:10.1364/oe.392507

Abstract

We propose a scalable readout interface for superconducting nanowire single-photon detector (SSPD) arrays, which we call the AQFP/RSFQ interface. This interface is composed of adiabatic quantum-flux-parametron (AQFP) and rapid single-flux-quantum (RSFQ) logic families. The AQFP part reads out the spatial information of an SSPD array via a single cable, and the RSFQ part reads out the temporal information via a single cable. The hybrid interface has high temporal resolution owing to low timing jitter in the operation of the RSFQ part. In addition, the hybrid interface achieves high circuit scalability because of low supply current in the operation of the AQFP part. Therefore, the hybrid interface is suitable for handling many-pixel SSPD arrays. We demonstrate a four-pixel SSPD array using the hybrid interface as proof of concept. The measurement results show that the hybrid interface can read out all of the pixels with a low error rate and low timing jitter.

Highlights

Superconducting nanowire single-photon detectors (SSPDs or SNSPDs) [1] have superior performance in terms of detection efficiency, count rate, and timing jitter [2,3,4], and have been used in many research fields, such as quantum optics [5], quantum information [6], optical communications [7], and fluorescent correlation spectroscopy [8]
We found that the temperature of the rapid single-flux-quantum (RSFQ) interface chip placed on the sample stage in a 0.1-W Gifford– McMahon (GM) cryocooler increased from 2.7 K to approximately 6 K by supplying a bias current of 370 mA to the RSFQ chip [24], which indicates that the scalability of RSFQ interfaces is limited by the amount of bias current
We proposed the adiabatic quantum-flux-parametron (AQFP)/RSFQ interface as a scalable readout interface for superconducting nanowire singlephoton detector (SSPD) arrays

Summary

Introduction

Superconducting nanowire single-photon detectors (SSPDs or SNSPDs) [1] have superior performance in terms of detection efficiency, count rate, and timing jitter [2,3,4], and have been used in many research fields, such as quantum optics [5], quantum information [6], optical communications [7], and fluorescent correlation spectroscopy [8]. Readout interfaces that operate with both low power and low supply current are required in order to demonstrate many-pixel SSPD arrays. In a previous study [25], we proposed using adiabatic quantum-flux-parametron (AQFP) logic [26] as readout interfaces for SSPDs because AQFP circuits can operate with both low power and low supply current. Note that the number of SFQ pulses in a pulse train generated by the DC/SFQ converter is not considered because only the first pulse turns the voltage driver into a voltage state, which ensures wider operating margins with regard to Isqd compared to a similar approach [37] (which attempts to generate a single SFQ pulse from a DC-SQUID stack). The mutual inductance between a wire from the SSPD array and the DC-SQUID is 64.8 pH, which is optimized for an Iin of approximately 15 μA

Experiment

Summary