GHz-range photon counting with single-photon avalanche photodiodes

In the past few years, there have been promising demonstrations of new approaches to short-gate (i.e., sub-nanosecond) operation of single-photon avalanche diodes (SPADs) with gating frequencies as high as 2 GHz. However, these demonstrations have had limitations, including operation at just a single fixed frequency, fairly high residual afterpulsing levels, and the lack of industrialization required for commercial deployment. For this proposed Phase 1 effort, we describe a development effort that will build on these new techniques but that will overcome the limitations of their initial demonstrations. In particular, we will realize frequency-agile GHz-range SPAD operation with low-afterpulsing single photon counting over a wide range of gating frequencies. With this high-frequency photon counting capability, we will also conduct more fundamental studies of avalanche pulse behavior and the afterpulsing phenomenon. The results of these characterization efforts will then be used to achieve further improvements in our GHz-range gating circuits.