Towards picosecond resolution with single-photon avalanche diodes

Abstract

Avalanche p–n photodiodes with uniform breakdown over the junction area are known to be capable of single-photon detection. An experimental study has been performed on the temporal resolution of these single-photon avalanche diodes (SPADs) in measurements of the shape of ultrashort light pulses. By using an active-quenching circuit, pulsed operation of the device has been obtained in accurately controlled conditions, avoiding spurious effects met in previous passive-quenching circuits. Laser pulses with durations down to 150 ps FWHM have been used; the results obtained show that the resolution is remarkably better than this value. Performances and limitations of SPADs are discussed; temporal resolutions of a few tens of picoseconds may be expected.