In this article, present the first detailed study of cascade switching in superconducting photon number resolving detectors. The detectors were made in the form of four parallel nanowires, coupled with the single-mode optical fiber and mounted into a closed-cycle refrigerator with a temperature of 2.1 K. We found out the value of additional false pulses (N_cas.sw.) appearing due to cascade switching and showed that it is possible to set up the detector bias current that corresponds to a high level of the detection efficiency and a low level of N_cas.sw. simultaneously. We reached the detection efficiency of 60% and N_cas.sw. = 0.3%.

中文翻译：

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光子数分辨超导单光子探测器的级联切换

在本文中，首次详细研究了超导光子数分辨探测器中的级联切换。探测器以四根平行纳米线的形式制成，与单模光纤耦合并安装在温度为 2.1 K 的闭环制冷机中。我们发现了额外的假脉冲值（N_cas.sw. ) 由于级联开关而出现，并表明可以设置对应于高水平检测效率和低水平的检测器偏置电流N_cas.sw. 同时地。我们达到了 60% 的检测效率和N_cas.sw. = 0.3%。