Single-photon detection in 900 nm range using InGaAs/InP single-photon avalanche diode

We report on a free-running single-photon detection at 941 nm using an InGaAs/InP single-photon avalanche diode (SPAD) operated with a passive quenching circuit. Adopting an avalanche signal height discrimination method, we can distinguish the photon-detection events from afterpulse noise events efficiently. The single-photon detection efficiency of 42 % was achieved with a dark count rate of 2 kHz and an afterpulse probability of 16 %.