High output semiconductor laser device utilizing a mesa-stripe optical

Abstract

A semiconductor laser device is provided with an optical confinement region constituted by first, second, third and fourth semiconductor layers provided on the upper part of a predetermined semiconductor substrate in contact with each other successively. The first and fourth semiconductor layers are smaller in refractive index than the second and third semiconductor layers, and the third semiconductor layer is larger in refractive index than the second semiconductor layer. On the other hand, the second and fourth semiconductor layers are larger in forbidden bandwidth than the third semiconductor layer. At least the first and fourth semiconductor layers are opposite in conductivity type to each other. In addition to this, the optical confinement region is formed into a mesa-stripe, and both side walls of this mesa-stripe which are substantially parallel to the traveling direction of a laser beam are embedded with a fifth semiconductor layer. Also, the width of the second semiconductor layer in a section perpendicular to the traveling direction of the laser beam and in the direction parallel to a junction within the optical confinement region is made larger than that of the third semiconductor layer. Accordingly, by virtue of this structure, a large output is ensured by this semiconductor laser device.