SSPD的低抖动SFQ信号读数

运用单磁通量量子(SFQ)读取技术的超导单光子探测器(SSPD)可以实现低抖动信号的读出。通过优化SFQ读出电路的电路参数,输入电流灵敏度被改善到10μA以下,且该结果比SSPD典型的临界电流小。实验使用脉冲发生器作为输入脉冲源,结果显示测出的SFQ读出电路的抖动值远低于目前测量装置系统超过15μA的抖动电流值。SSPD连接到SFQ读出电路的测量抖动值在37 ps的半高全宽(FWHM)时的SSPD偏置电流约为18μA,这是对传统的没有SFQ读出电路,抖动为67 ps的FWHM的显著提高。

Single flux quantum signal with low-jitter readout by using superconducting single photon detector

Using single-flux-quantum （SFQ） readout technology with superconducting single-photon detectors （SSPDs） can get low-jitter signal readout. Through optimizing the parameters of SFQ readout circuit, sensitivity of the input current was improved under 10 μA, which is smaller than a classic critical current of SSPD. A pulse pattern generator was used as an input pulse source in this experiment, and the result shows that the measured jitter of the SFQ readout circuit is far below the system jitter of the measurement setup whose input current level is above 15 μA. When the measured jitter of the SSPD connected with the SFQ readout circuit is 37 ps full width at half maximum （FWHM）, an SSPD bias current is around 18 μA, and this is a significant improvement compared to 67 ps FWHM jitter,which is observed in conventional readout without an SFQ readout circuit.