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 crosscorrelation 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-ofFlight (ToF) and to calculate the measured distance. In this work, an innovative way of performing an approximated crosscorrelation 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.