arXiv:1312.2636 · Applied Physics Letters
Free-running InGaAs single photon detector with 1 dark count per second at 10% efficiency
Boris A. Korzh, Nino Walenta, Tommaso Lunghi, N. Gisin, Hugo Zbinden
Abstract
We present a free-running single photon detector for telecom wavelengths based on a negative feedback avalanche photodiode (NFAD). A dark count rate as low as 1 cps was obtained at a detection efficiency of 10%, with an afterpulse probability of 2.2% for 20 μs of deadtime. This was achieved by using an active hold-off circuit and cooling the NFAD with a free-piston stirling cooler down to temperatures of −110 °C. We integrated two detectors into a practical, 625 MHz clocked quantum key distribution system. Stable, real-time key distribution in the presence of 30 dB channel loss was possible, yielding a secret key rate of 350 bps.