Capacitive quenching measurement circuit for Geiger-mode avalanche photodiodes

Characterization of Geiger-mode avalanche photodiodes operated in gated mode requires fast rising-edge, well-defined over-bias pulses, and effective avalanche quenching. There has not been a suitable circuit that meets both criteria, thus, making systematic characterization and accurate comparison of these devices difficult. We present a capacitive quenching circuit (CQC) that satisfies both criteria and, thus, offers advantages over existing options such as a gated passive quenching circuit (G-PQC) and gated-mode operation without avalanche quenching. Test results using a commercial Si Geiger-mode avalanche photodiode, together with an experimental comparison between the CQC and the standard G-PQC circuit, are reported. The advantages of the CQC over the G-PQC circuit are demonstrated through comparisons of experimental over-bias pulses, distribution of avalanche current pulses, and dark count rate data. By each metric, the CQC is shown to yield results that are superior to those obtained using a standard G-PQC circuit.