A Multi-Time-Gated SPAD Array with Integrated Coarse TDCs

Time-gating of single-photon avalanche diodes (SPADs) was commonly used as a method to reduce dark noise in biomedical imaging applications where photon events are correlated with reference clock. also obtain timing information by shifting the gate windows applied SPAD array. However, this approach, fine resolution comes at cost lengthened measurement time due large number counts required for each shift. As solution, we present multi-time-gated array that simultaneously applies shifted an SPADs, which has potential compared single window. Compared similar works, design fully integrated multi-gate generation using shared circuitry functions coarse time-to-digital converter. The proposed array, fabricated TSMC 65 nm standard CMOS process, achieved median count rate (DCR) 37 kHz, 4.37 ns widths, 550 ps resolution, and peak detection probability (PDP) 42.9% 420 nm, all 0.8 V excess bias.