We introduce the first integrated active quenching circuit (I-AQC) that drives an avalanche photodiode (APD) above its breakdown voltage, in order to detect single photons. Based on the I-AQC, we developed a compact and versatile photon-counting module suitable for applications in which very weak optical signals have to be detected, as for instance, photon correlation spectroscopy, luminescence measurements, and laser ranging. The prototype photon-counting module features quenching pulses up to 60 V amplitude, minimum dead time of less than 36 ns, corresponding to a saturated counting rate exceeding 25 Mcounts/s, user-controllable hold-off time, for reducing the afterpulsing effect, and nanosecond gating capability. The power dissipation is 60 mW in stand-by conditions, and the module size is less than 1 cm/spl times/2 cm.
['Franco Zappa', 'Massimo Ghioni', 'S. Cova', 'Carlo Samori', 'Andrea Giudice']
An integrated active-quenching circuit for single-photon avalanche diodes