Intrinsic Jitter in Photon Detection by Straight Superconducting Nanowires
Timing jitter inherent in photon detection by superconducting nanowire single-photon detectors has different values and behaves differently for detection events originating in bends and in straights of nanowires. Generally, jitter is larger for events in bends. Although, for typical meandering nanowire, contribution of bends to the integral jitter is almost negligible due to small geometric weight of bends in the meander, it reduces the accuracy of extracting the value of local jitter in straights. Here we report on the intrinsic jitter, which was measured in a straight nanowire without bends. Standard deviation in the intrinsic jitter for detection events in the straight nanowire is smaller than 6.5 ps for photons with the wavelength 794 nm and 7.7 ps for 1560 nm. This value is less than jitter magnitudes in straights, which were extracted from the jitter measured previously for the meandering nanowire. Coupling of photons to the nanowire through sufficiently long optical fiber increases integral jitter and causes asymmetry in the jitter histogram. However, this optical asymmetry differs qualitatively from the asymmetry caused by the detection process itself at small photon energies.