We propose and demonstrate all-optical DPSK signal regenerator with differential encoder employing a newly proposed all-optical T-type flip-flop (T-FF). The proposed configuration of an all-optical T-FF employs a counter-faced configuration of two semiconductor optical amplifier Mach-Zehnder interferometers (SOA-MZIs) to realize a short feedback path without loopback waveguide for high-speed operation. Numerical simulation reveals that it can operate as a T-FF at bit-rate of 10 Gb/s under the condition of carrier life time of 10 ps. We also experimentally demonstrate the operation of proposed all-optical T-FF at bit-rate of 2 Gb/s with fiber-based experimental setup. Finally, we demonstrate the possibility of DPSK signal regenerator with the combination of the proposed all-optical T-FF and standard SOA-MZI by numerical simulations and it can drastically improve the quality of DPSK signal degraded in transmission. We believe that the proposed configuration of an all-optical DPSK regenerator is promising for future optical networks.