Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE
Low temperature performance of free-running InGaAs/InP single-photon negative feedback avalanche diodes
Boris A. Korzh, Hugo Zbinden
Abstract
Free-running single photon detectors at telecom wavelengths are attractive for many tasks in quantum optics. However, until recently, the convenient and compact InGaAs/InP avalanche photodiodes did not operate with satisfactory performance in this regime due to high dark count rates and afterpulsing effects. Recent development of negative feedback avalanche diodes (NFADs) enabled very fast passive quenching of the avalanche current, effectively reducing the afterpulse probability and subsequently allowing free-running operation. Here, we present analysis of NFAD operation at low temperatures, down to 163 K, which reveals a significant reduction of the dark count rate. We succeeded in developing a compact single photon detection system with a dark count rate of ~1 cps at 10% detection efficiency. To ensure that the NFAD is in a well-defined initial condition during the characterization of the detection efficiency and afterpulsing, we use a recently developed FPGA based test procedure suitable for free-running detectors. To demonstrate the performance of the detector in a real-world application we integrate it into a 1.25 GHz clocked quantum key distribution system. An optimization of the detector temperature allowed secret key distribution in the presence of more than 30 dB of loss in the quantum channel.