Room-Temperature Single-Photon Detection With 1.5-GHz Gated InGaAs/InP Avalanche Photodiode

A room-temperature single-photon detector was demonstrated with InGaAs/InP avalanche photodiode (APD) with negligible afterpulse effect and low dark count rates. The APD was operated in 1.5-GHz sinusoidally gated Geiger mode by using appropriate low-pass filters to minimize the capacitive spike noises. A detection efficiency of ~21% was attained with the dark count rate of 8×10
^-5
per gate and a afterpulse probability of 1.4%, showing excellent performance without cooling. Moreover, we varied the amplitude of the sinusoidal gates to further optimize the performance. The room-temperature single-photon detectors with compact structures and low power consumption offer advantages in practical quantum key distribution and ultradistance laser ranging systems.