A semiconductor laser with a converging output beam

Abstract
Semiconductor lasers with converging output beams are reported for the first time. The lasers have a low-gain region on the center of the mesa stripe near one cleaved facet. The low-gain region distorts the phase front of the guided light and beam convergence results. The width of the laser beam in the direction parallel to the junction plane decreases with distance from 30 μm at the facet down to 7 μm at 111 μm off the facet. Moreover, the one-dimensional optical power density increases with distance in accordance with the decrease in beam width.