Superconducting nanowire single photon detector with on-chip bandpass filter

Abstract

Dark count rate is one of the key parameters limiting the performance of the superconducting nanowire single photon detector (SNSPD). We have designed a multi-layer film bandpass filter that can be integrated onto the SNSPD to suppress the dark counts contributed by the stray light and blackbody radiation of the fiber. The bandpass filter is composed of 16 SiO2/Si bilayers deposited onto the backside of a thermally oxidized Si substrate. The substrate shows an excellent bandpass filter effect and provides a high transmittance of 88% at the central wavelength of the pass band, which is the same as that of the bare substrate. The SNSPDs fabricated on the substrate integrated with the bandpass filter show conspicuous wavelength-sensitive detection efficiency. The background dark count rate is reduced by two orders of magnitude to sub-Hz compared with the conventional SNSPD (a few tens of Hz). The detector exhibits a system detection efficiency of 56% at DCR of 1 Hz, with the measured minimal noise equivalent power reaching 2.

Self-aligned multi-channel superconducting nanowire single-photon detectors

“…In recent years, superconducting nanowire single-photon detectors (SNSPDs) 1,2 have emerged as successful alternatives to traditional InGaAs/InP-based single-photon avalanche photodiodes (SPADs) in the realm of near-infrared single photon detection due to their excellent quantum efficiency, [3][4][5][6] short timing jitter, [6][7][8] ultralow dark count rates, [9][10][11] fast reset time with only several nanoseconds, 6,12,13 and photon number resolving ability. [14][15][16] To date, most of SNSPD systems utilize fiber coupling method because of advantages over free-space coupling, including lower dark count rates, more compact size and robustness to vibration.…”

Field Test of Measurement-Device-Independent Quantum Key Distribution

“…Second, with the development of the SNSPD technology, the detection efficiency can be further improved [34]. Besides, the dark count rate may be effectively reduced to sub-Hertz [18]. Last but not least, with the decoy-state parameters and the basis choice optimized [35], we can expect a faster key rate generation to enable some practical applications.…”

“…In this field-environment test, we develop a decoy-state MDIQKD system, operated at a clock rate of 75 MHz and with a superconducting nanowire single photon detector (SNSPD) system of more than 40% detection efficiency [18]. Our experimental setup is illustrated in Fig.…”

Recent Progress and Application of Superconducting Nanowire Single-Photon Detectors

“…It has been shown that the extrinsic DCR could be reduced by using cold optical bending fiber [29]. Furthermore, SSPDs with a dielectric multilayer designed to cut the extrinsic DCR also have been presented [31], [32].…”