The invention belongs to the technical field of
quantum secret communication, and particularly discloses a
synchronizing device for a
quantum key distribution (QKD)
system. The
synchronizing device comprises a transmitting device for transmitting
synchronizing light and
signal light, a
photoelectric conversion device, an adjustable time
delay module, a single
photon detector and a
data processing module, and is characterized in that the frequency of the
signal light sent by the transmitting device is much greater than the frequency of the synchronizing light, the frequency of the
signal light is several times that of the synchronizing light, the synchronizing light and the
signal light are transmitted in the same
optical fiber, a
low jitter frequency doubler is arranged between the
photoelectric conversion device and the adjustable time
delay module and is used for doubling the frequency of a synchronized electrical signal output by the
photoelectric conversion device to be the same as the frequency of the
signal light, and then outputting the signal, the adjustable time
delay module uses the signal to generate a door
control signal of the single
photon detector with the same frequency of the
signal light, and the
data processing module uses the signal to finish subsequent
processing. The synchronizing device can reduce the
impact of the synchronizing light on the signal light, can guarantee normal door
control signal of the
detector, and can effectively improve the
code rate of the QKD
system.