Complete single-photon counting and timing module in a microchip.
A complete module for single-photon counting and timing is demonstrated in a single chip. Features comparable with or better than commercially available macroscopic modules are obtained by integration of an active-quenching and active-reset circuit in complementary metal-oxide semiconductor technology together with a single-photon avalanche diode (SPAD). The integrated SPAD has a 12-microm-diameter sensitive area and operates with an overvoltage above breakdown adjustable up to 20 V. With a 5-V overvoltage the photon detection efficiency peaks above 40% around 500 nm, and the dark-counting rate is lower than 600 counts/s at room temperature. The overall counting dead time is 33 ns.