InGaAsP-InP avalanche photodiodes for single photon detection

In this paper, we describe the design, characterization, and modeling of InGaAsP/InP avalanche diodes designed for single photon detection at wavelengths of 1.55 and 1.06 mu m. Through experimental and theoretical work, we investigate critical performance parameters of these single photon avalanche diodes (SPADs), including dark count rate (DCR), photon detection efficiency (PDE), and afterpulsing. The models developed for the simulation of device performance provide good agreement with experimental results for all parameters studied. For 1.55-mu m SPADs, we report the relationship between DCR and PDE for gated mode operation under a variety of operating conditions. We also describe in detail the dependence of afterpulsing effects on numerous operating conditions, and in particular, we demonstrate and explain a universal functional form that describes the dependence of DCR on hold-off time at any temperature. For 1.06-mu m SPADs, we present the experimentally determined relationship between DCR and detection efficiency for free-running operation, as well as simulations complementing the experimental data.