  In this paper, we have investigated a self-developed sine wave gated (SWG)
single-photon detector (SPD) for 1550 nm wavelength primary for quantum key
distribution (QKD) usage. We have investigated different gate parameters`
influence on the SPD`s noise characteristics. We have admitted that with an
increase of gating voltage and constant value of quantum efficiency (QE), the
dark count rate (DCR) decreases. There have been made some recommendations to
improve SPD`s and whole QKD device's characteristics based on these
observations. There have been discovered the quick rise of the DCR value with
the increase of gating voltage above some certain value and this value was
different for different detectors. It has been shown that universal empirical
dependence compilation to connect control and operational parameters of SPD is
a non-trivial task.
