Abstract: An optoelectronic device, such as a laser of the ridge waveguide type, can be provided with the necessary mesa (14) by means of wet or dry etching with a mask (20). The etching process is stopped when an etching stopper layer (5) is reached. A laser obtained by wet etching is indeed least expensive, but it is found to have a kink in its power-current characteristic at an undesirably low power value.According to the invention, such a laser must be manufactured in that the mask (20) used is given a width which is (much) greater than the width desired for the mesa (14), and in that, after a (preferably wet) etching process down to or down to close to the etching stopper layer (5), etching is continued with a wet isotropic etchant which is selective relative to the etching stopper layer (5) until the mesa (14) formed has the desired width.A very narrow and steep mesa (14) can thus be realized in an inexpensive manner.

Abstract: A diode laser is disclosed that is self-pulsating without an increase in the starting current or a decrease in the efficiency. A special coating on an end face of the laser comprises in order a first mirror, a medium having an optical thickness which is at least substantially equal to an integer number of times half the wavelength of the generated electromagnetic radiation, and a second mirror. The coating comprises exclusively materials which have a higher bandgap value than that which corresponds to the wavelength of the generated radiation, while the reflectivities of the mirrors and the deviation of the optical thickness of the medium with respect to an integer number of times half the emission wavelength are chosen such that the group velocity dispersion (GVD) adjacent the wavelength of the generated electromagnetic radiation is negative, and preferably a minimum.