Abstract: A semiconductor laser having mirror faces serving as resonators, in which the active laser region (2) includes end zones adjoining the mirror faces which have implanted ions, preferably protons, with associated crystal damage. The end zones have a length which is at least equal to the diffusion length of the recombining charge carriers in the end zones. As a result of the high recombination rate in the end zones substantially no non-radiating recombination occurs at the mirror faces so that mirror erosion is avoided.The invention relates to a method in which the end zones are formed by an ion bombardment on the upper surface of the semiconductor wafer with a number of lasers, which wafer at the area of the mirror (cleavage) faces to be formed is provided with grooves which do not extend up to the active layer, in which grooves the end zones are provided via an ion bombardment through the active layer.

Abstract: A semiconductor laser with a double hetero junction includes a strip-shaped semiconductor contact layer which is present on a passive layer of the same conductivity type, with a highly doped zone of the same conductivity type which extends over at least a part of the thickness of the contact layer and beside the contact layer in the passive layer so as to increase the radiation mode stability. According to the invention, the highly doped zone extends only over a part of the thickness of the passive layer in such a manner that below and beside the contact layer a difference in effective refractive index of at least 0.0005 and at most 0.005 is obtained.

Abstract: A semiconductor laser includes an active layer of a first conductivity type comprising a strip-shaped active region formed by a doping of the second conductivity type over at least a part of the thickness of the active layer. According to the invention, the active region consists of a number of zones of the second conductivity type which are separated by material of the first conductivity type and which, viewed in the longitudinal direction of the active region, have a maximum dimension of at most 20 .mu.m. Upon ageing, crystal defects in the zones will not expand beyond the zones, thus extending the usable lifetime of the laser.

Abstract: A semiconductor laser/amplifier is disclosed in which the radiation oscillates only in one longitudinal mode. According to the invention this is achieved by a strip-shaped active region which exhibits periodic variations in amplification (and preferably also in the amplification profile) in its longitudinal direction over at least a part of its length. The period of the amplification variation is at least ten times the wavelength of the radiation.

Abstract: An injection laser includes two substantially parallel mirror side faces and a substantially stripe-shaped contact member having a comparatively large width. The stripe-shaped contact member has a shape and disposition with respect to the mirrors such that laser action can be obtained only in a comparatively narrow stripe of the active layer. For example, the contact member may be arranged to extend obliquely with respect to the mirrors instead of at right angles thereto.

Abstract: A semiconductor injection laser includes two contact regions on two oppositely-located major surfaces of the semiconductor body. One of these contact regions is divided into two sub-contact regions which are separated by a gap, and the active zone of the laser can be moved in a direction transverse to that of the laser beam by controlling the current distribution between the two sub-contact regions in order to move the laser beam.

Abstract: The invention relates to a method in which a system of layers with a contact layer of gallium arsenide is formed epitaxially. In a second epitaxy treatment a layer of gallium aluminum arsenide is formed selectively. In order not to form the latter layer on the contact layer of gallium arsenide, the latter is shielded from gallium aluminum arsenide by means of a masking layer having a composition which differs from that of the layer to be provided selectively, so that the masking layer can afterwards be removed selectively.