A single photon detector operating in the Geiger mode is cooled to a moderate temperature by using Peltier cooling, and a gate pulse is coupled to the avalanche diode through capacitance. It uses a moderate delay and sampling gate modulation to prevent the positive and the negative transient pulses from influencing the detection of true photon avalanches, a dead time modulation feedback control circuit to suppress the afterpulsing, and an optimized circuit to reduce the dark counts. The performance test shows that at the optimum operation point the quantum efficiency is about 18%, the dark count rate is less than 4×10-6 ns-1 and the noise-equivalent power is 2.4×10-19 W/Hz1/2.