Free-running, room temperature operation of an InGaAs/InP single-photon avalanche diode

Passive quenching operation of an InGaAs/InP single-photon avalanche diode detector at low excess bias is reported in terms of the key figures of merit including afterpulsing analysis. The reduced charge required to measure individual photon events meant that room temperature single-photon counting at 1550 nm wavelength was achievable without the requirement of electrical gating and with negligible afterpulsing effects evident.