Photon detection at 1 ns time intervals using 16-element SNSPD array with SFQ multiplexer
Shigehito Miki, Shigeyuki Miyajima, Fumihiro China, Masahiro Yabuno, Hirotaka Terai
Abstract
We demonstrate the high-speed operation of a 16-element superconducting nanostrip single-photon detector (SNSPD) array with a single flux quantum (SFQ) multiplexer. The SFQ multiplexer can reshape the output signals from 16-element SNSPD into pulses with durations shorter than 1 ns and bundle these pulses into one output line, which is advantageous for high-speed operation of the SNSPD array system. We confirmed the correct operation of the 16-element SNSPD system with a system detection efficiency of 80% at a wavelength of 1550 nm, timing jitter of 45 ps, and successful observation of photons at 1 ns time intervals as distinguishable output pulses. The reduction in detection efficiency could also be suppressed to <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>∼</mml:mo> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>0.93</mml:mn> </mml:mrow> </mml:math> during the dead time of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>∼</mml:mo> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>10</mml:mn> </mml:mrow> </mml:mrow> <mml:mspace width="thickmathspace"/> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">n</mml:mi> <mml:mi mathvariant="normal">s</mml:mi> </mml:mrow> </mml:mrow> </mml:math> for each SNSPD pixel when the incident photon flux was relatively low at 0.1 photon/pulse.