Room-Temperature Single-Photon Detector Based on InGaAs/InP Avalanche Photodiode With Multichannel Counting Ability

Using a capacitance balancing circuit, we achieved infrared single-photon detection based on an InGaAs/InP avalanche photodiode (APD) with a low dark count rate and negligible afterpulse effect at room temperature of 290 K. Detection efficiency of 9.80% was attained with the dark count rate of 6.62 × 10^-4 per gate, showing that the detector could work efficiently even at room temperature without Peltier cooling. Moreover, the detector was operated in an arbitrary gated mode, meaning that more than one gating pulse was applied on the APD during one period. The single-photon detector working in this mode was capable of multichannel photon counting for practical quantum key distribution.