InGaAsP avalanche photodetectors for near IR single photon detection

Single photon detectors are key components for a wide range of applications in the near infrared (NIR) wavelength range between 1.0 and 1.7 mu m. To achieve high performance single photon detection in the NIR wavelength range, single photon avalanche diodes (SPADs) based on the InGaAsP quarternary material system lattice-matched to InP are likely to provide the most appropriate solution in numerous situations. 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 mu m and 1.06 pm. Critical performance parameters of these SPADs, including dark count rate, photon detection efficiency, and afterpulsing have been studied both experimentally and theoretically. The models developed for the simulation of device performance provided good agreement with experimental results. The relationship between dark count rate and photon detection efficiency is investigated for 1.55 mu m SPADs under gated mode operation and 1.06 mu m SPADs under both gated mode and free-running operations. We also describe in detail the dependence of afterpulsing effects on numerous operating conditions.