CMOS Transceiver with Time-Gated 4×8 SPAD Array and Width-Controlled Laser Diode Pulser for Time-Domain Diffuse Optics Measurements

A CMOS transceiver for time-domain diffuse optics measurements has been fabricated with 150 nm CMOS technology on a single die. The pulse width of a laser diode (LD) can be adjusted from 835 ps to 3 ns, with a resolution of $\sim 100$ ps, for different types of LDs. The time-gated and time-resolved $4\times 8$ SPAD array can be loaded to Geiger mode within less than 150 ps. The TDC can capture returning photons with a resolution of $\sim 52.46$ ps, and the data is stored in 128 14-bit counters. The repetition rate can be up to 12.5 MHz. At a 1 Hz sample rate, with 1 000 000 pulses, the average power consumption of the transceiver was 25.76 mW, excluding the FPGA controller.