Laser pulser for a time-of-flight laser radar

A laser pulser for a pulsed time-of-flight laser radar is presented. The pulser is constructed using a single avalanche transistor in order to keep the schematic simple and to avoid the problems encountered when connecting several avalanche transistors in parallel. The schematic of the laser pulser was optimized and it was noticed that the optical peak pulse power of the laser can be increased significantly by adding a parallel capacitor to the laser. The measured increase of the optical power was up to 26%. The simulations show that the parallel capacitor and also the serial inductances of the components in the laser pulser play a significant role in adjusting the shape of the current pulse. In order to find the transistor, which gives the highest current, the properties of several transistor types were compared. It was noticed that there can be a great difference between the avalanche properties of a group of transistors even if they are of the same type.