Geiger-mode avalanche photodiodes for photon-counting communications

Arrays of photon-counting avalanche photodiodes enable laser-communications receivers with unprecedented sensitivity at 1.06-/spl mu/m wavelength. Arrays with 64 elements were fabricated in the InGaAsP/InP materials system and were bump-bonded to a custom CMOS integrated circuit. The integrated circuit uses a novel nonblocking architecture to continuously report both time-of-arrival for incoming photons as well as their spatial location on the array. Near room temperature, the best detectors have: 45% photon detection efficiency, 65-kHz dark count rate, and a 1.6-/spl mu/s reset time to avoid after-pulsing.