Detection of ultra-weak laser pulses by free-running single-photon detectors: Modeling dead time and dark counts effects

In quantum communication systems, the precise estimation of detector's response to incoming light is necessary avoid security breaches. The typical working regime uses a free-running single-photon avalanche diode in combination with attenuated laser pulses at telecom wavelength for encoding information. We demonstrate validity an analytical model this which considers effects dark counts and dead time on measured count rate. For purpose gaining better understanding these effects, photon detections were separated from via software-induced gating mechanism. was verified by experimental data mean numbers covering three orders magnitude as well repetition frequencies below above inverse time. Consequently, our would be interest predicting detector not only field communications, but also any other physics experiment where high detection rates are needed.