A Novel Mixed-Signal Silicon Photomultiplier with Analog-Domain Cross-Correlation Computation for LiDAR Applications

Light Detection and Ranging (LiDAR) is a widespread technique for distance measurements used in several applications. In this work, a novel Mixed-Signal Silicon Photomultiplier (msSiPM) with analog-domain cross-correlation computation for LiDAR applications is presented. Cross-correlation technique is commonly implemented at the end of the LiDAR system signal chain to estimate the Time-of-Flight (ToF) and to calculate the measured distance. In this work, an innovative way of performing an approximated cross-correlation inside the detector frontend is presented and simulated. In particular, the typical impulse response of an analog-SiPM (aSiPM) with a specific dead-time is replaced by a custom impulse response by means of a microcell-level Pulse Shaper stage. In this way, it is possible to tune the pulse to approximate the time-reversed shape of the laser envelope and to perform an analog cross-correlation. Simulations have been carried out in MATLAB software: by using an msSiPM instead of an aSiPM, an advantage in terms of Signal-to-Noise Ratio (SNR) of 6 dB and of Signal-to-Background Ratio (SBR) of about 23 dB is obtained.