Suppressing Dark Counts of Multimode-Fiber-Coupled Superconducting Nanowire Single-Photon Detector

Suppressing Dark Counts of Multimode-Fiber-Coupled Superconducting Nanowire Single-Photon Detector

Large active-area superconducting nanowire single-photon detectors (SNSPDs) coupled with multimode fibers (MMFs) can provide high light-gathering capacity, which is essential for free-space detection applications in photon-starved regimes. However, MMF-coupled SNSPDs often suffer from large system d...

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Bibliographic Details
Main Authors: Chengjun Zhang, Weijun Zhang, Lixing You, Jia Huang, Hao Li, Xingqu Sun, Heqing Wang, Chaolin Lv, Hui Zhou, Xiaoyu Liu, Zhen Wang, Xiaoming Xie
Format: Article
Language:English
Published: IEEE 2019-01-01
Series:IEEE Photonics Journal
Online Access:https://ieeexplore.ieee.org/document/8812958/
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Summary:Large active-area superconducting nanowire single-photon detectors (SNSPDs) coupled with multimode fibers (MMFs) can provide high light-gathering capacity, which is essential for free-space detection applications in photon-starved regimes. However, MMF-coupled SNSPDs often suffer from large system dark count rates (DCR<sub>sys</sub>) over kHz due to blackbody radiation of the MMF at room temperature. Such large DCR<sub>sys</sub> would significantly degrade signal-to-noise ratio (SNR) of the receiving system. This paper reports an MMF-coupled large-active-area SNSPD system with low DCR<sub>sys</sub> by using a homemade cryogenic MMF filter bench. The filter bench, which consists of lenses and optical filters, can provide a high transmittance of about 80&#x0025; at the central wavelength of the passband (1550&#x00A0;&#x00B1;&#x00A0;12.5&#x00A0;nm) and a wide blocking range from 500&#x00A0;nm to over 6000&#x00A0;nm at 40&#x00A0;K. With using the filter bench, the DCR<sub>sys</sub> of an MMF-coupled 9-pixel SNSPD array with an active area of 50 &#x03BC;m in diameter is greatly suppressed by 23&#x00A0;dB with 1&#x00A0;dB loss of system detection efficiency (SDE). The detector demonstrates an SDE of 51&#x0025; at a DCR<sub>sys</sub> of 100 Hz for 1550&#x00A0;nm photons. Thus, SNR of the detector is enhanced by about 160 times and the noise equivalent power is improved to 3&#x00D7;10<sup>&#x2212;19</sup> W&#x002F;Hz<sup>1&#x002F;2</sup>.
ISSN:1943-0655

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