  Up-conversion single photon detector (UCSPD) has been widely used in many
research fields including quantum key distribution (QKD), lidar, optical time
domain reflectrometry (OTDR) and deep space communication. For the first time
in laboratory, we have developed an integrated four-channel all-fiber UCSPD
which can work in both free-running and gate modes. This compact module can
satisfy different experimental demands with adjustable detection efficiency and
dark count. We have characterized the key parameters of the UCSPD system.
