Akiko Tada

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 %.

Single-photon buffer at a telecommunication wavelength using a fiber-optic switch

We demonstrated an efficient fiber-optic single-photon buffer (SPB) at 1550 nm. The SPB can control and give discrete time delays to a single-photon. Moreover the SPB is passively polarization-stable, and consequently the polarization-based quantum state of light can be maintained. The insertion loss of the SPB is as low as 2.98 dB, which indicates that it can be used for enhancement of efficiencies of heralding single-photon sources and multi-photon interference experiments.