A high-speed/power laser transmitter for single photon imaging applications

A compact laser pulser emitting ~100 ps, ~10 W pulses at >100 kHz is presented. The high pulsing frequency is achieved using a MOSFET-based current driver, whereas the high pulse power is a merit of the used laser diode with an asymmetric waveguide structure leading to enhanced gain switching. The pulsing frequency is higher than with avalanche transistor based current pulsing circuits due to lower heating, and the current pulse width is shown to be even shorter than with avalanche transistor based circuits. The laser diode transmitter was developed especially for the pulsed time-of-flight laser radar application utilizing a single photon avalanche diode (SPAD) matrix as the detector element. A demonstration measurement is done enabling centimeter-precision distance measurement to 50 m in a measurement time of ~5 ms outdoors in sunny weather.