Single photon avalanche photodiodes for near-infrared photon counting

Abstract

InP-based single photon avalanche diodes (SPADs) have proven to be the most practical solution currently available for many applications requiring high-performance photon counting at near-infrared wavelengths between 1.0 and 1.6 µm. We describe recent progress in the design, characterization, and modeling of InP-based SPADs, particularly with respect to the dark count rate vs. photon detection efficiency metric of devices optimized for use at both 1.55 μm and 1.06 μm. In this context, we report for the first time dark count probabilities as low as 7 x 10-7 ns-1 for fiber-coupled 1.55 μm SPADs operated at 20% detection efficiency and 215 K. Additionally, because of the critical role played by afterpulsing in limiting photon counting rates, we describe recent characterization of the dependence of afterpulsing effects on SPAD operating conditions such as photon detection efficiency, repetition rate, and bias gate length.