Emission properties of the double-proton bombarded laser - Including kinks and self-sustained oscillations

The double-proton bombarded laser is similar to the conventional proton delineated stripe laser except that it combines two proton bombardments, one shallow and the other deep, in one laser. The "strangling" effect that results from these two proton bombardments provides very good carrier confinement in the active region under the stripe. The emission properties of this laser are discussed in relation to the problems of kinks in the light-current characteristics and self-sustained oscillations in the light output of the laser. It is found that a kink always occurs, while self-sustained oscillations hardly ever occur. The good carrier confinement in the lateral plane seems to be the reason why the laser is so stable temporally. This indicates that current spreading in the lateral plane may be a major cause of self-sustained oscillations in narrow striped lasers in which there is poor carrier confinement. However, the severe kinks in the light-current characteristics which tend to move to lower levels, probably due to some annealing of the proton-bombardment near the active layer, are expected to limit the usefulness of the laser.