A Current-Mode Photon Counting Circuit for Long- Range LiDAR Applications

Photon counting techniques are becoming more critical in fields such as LiDAR, high energy physics (HEP) and positron emission tomography (PET). For space-based aerosol-cloud-ocean (ACO) LIDAR, the total aggregate photon flux signal has a very high dynamic range from a single-photon up to giga-photons per second for a single channel. A current-mode front-end can accommodate this counting dynamic range over a wide range of input signal current pulse amplitudes. A multi-channel current-mode photon counting circuit was designed, simulated, and fabricated in a standard 180 nm SiGe BiCMOS process. This photon counting circuit achieved a maximum count rate of 500 MHz with a 300 ps FWHM pulse width at amplitudes of 5μA to 1.25 mA.