Semiconductor laser

Abstract

An improved semiconductor laser of the type composed of a sequence of semiconductor layers forming a heterostructure diode including a substantially homogeneously doped layer defining a laser active zone having a laser radiation exit face perpendicular to the layers, two respectively differently doped semiconductor layers disposed at respectively opposite sides of the active zone, a monocrystalline outer layer located in the layer sequence and spaced from one of the differently doped semiconductor layers by an additional layer, a trough-shaped recess extending essentially perpendicularly to the radiation exit face formed in the outer major surface of the monocrystalline layer, and means disposed adjacent the recess for constricting the current flow in the forward direction of the diode to a narrow strip-shaped region in the laser active zone. The series resistance of such a laser is lowered in that the bottom of the recess is formed by the additional semiconductor layer adjacent the monocrystalline layer and an electrically conductive contact is provided on at least the bottom of the recess.