A stochastic approach for optimizing the required number of sub-pixels in Silicon Photomultipiler (SiPM) for optical radar applications (LiDAR)

Abstract

CMOS Silicon Photomultiplier (SiPM) composed of a mosaic array of SPADs (single photon avalanche diode in Geiger Mode) combined in parallel, is the building block of optical radars based on a LIDAR (light detection and ranging). An open essential design parameter is the required number of sub-pixels for adequate detection of a packet of n photons, taking into consideration that each sub-pixel, composed of a single SPAD, can detect only the first photon. This study evaluates this design parameter based on a stochastic approach, where the random number of incident photons as well as the detection probability of each SPAD is taken into consideration. An expression for Signal to Noise Ratio (SNR) is developed, yielding the optimal number of sub-pixels required for a practical implementation of a LIDAR.