System for gated detection of optical pulses containing a small number of photons using an avalanche photodiode

摘要

An avalanche-type detector circuit includes an avalanche-type photon detector device, a coupling capacitor, a bias network, a first transmission line and a second transmission line. The coupling capacitor has a first terminal that is coupled to a first terminal of the avalanche-type photon detector device. A first terminal of the bias network is coupled to the first terminal of the avalanche-type photon detector device, while a second terminal of the bias network is coupled to a bias voltage so that the avalanche-type photon detector device is reverse biased. A first end of the first transmission line is coupled to a second terminal of the coupling capacitor, and second end of the first transmission line is terminated by an open-circuit termination. A first end of the second transmission line is coupled to a second terminal of the avalanche-type photon detector device. The second end of the second transmission line is terminated by a short-circuit termination. A bias pulse voltage Vpulse is coupled to the second terminal of the coupling capacitor such that the bias pulse voltage reverse biases the avalanche-type photon detector device to be greater than a reverse breakdown voltage Vbr of the avalanche-type photon detector device during a duration of the bias pulse voltage Vpulse. A round-trip propagation delay along the first transmission line is substantially equal to a round-trip propagation delay along the second transmission line.