Semiconductor laser device

摘要

A semiconductor laser includes a mesa-striped laser structure. A substrate has layered on it an active layer with a refractive index higher than that of, and with an energy gap smaller than that of the substrate. A first electrode is formed under the substrate. A cladding layer of a conductivity type different than that of the substrate overlays the active layer. A multilayered burying crystal includes, at the sides of the mesa-striped laser structure, successively first, second and third burying layers. The first and third burying layers are of the same conductivity type as the substrate. The second burying layer is of a conductivity type different from that of the substrate. A cap layer of a conductivity type different than the substrate covers the upper face of the mesa-striped structure and an upper face of the third burying layer. A second electrode is formed on the cap layer. Injected current flowing into a thyristor composed of the cap layer and the three burying layers can be suppressed.