New technique for generating powerful picosecond optical pulses from semiconductor lasers for high-resolution pulsed laser radar systems

Abstract

The generation of picosecond high-power single optical pulses is a problem of increasing importance especially in high PRF short-range laser radar systems for fast and reliable 3D-measurements with submillimeter accuracy, and satisfying class-1-laser specification. Presently we report on a novel technique for generating ps high-power optical pulses based on a fast change in the type of optical waveguiding from index- to gain-guiding in the laser structure pumped by nano-second current pulses of high amplitude. This change leads to a very efficient radiation of a gain-switched pulse which may be then followed by an additional Q-switched optical pulse. The new technique can be realized for any laser structure having weak index-guiding and nonmonotoneous dependence of the modal gain on carrier density in the laser active area (like single heterojunction (SH) lasers, single quantum well ridge-guide (SQW RG) lasers with low lateral confinement, etc.).