Abstract: An optical film of the present invention is of multi-layered structure which has a high-refractive-index layer composed of titanium oxidic nitride, aluminum oxidic nitride, or silicon oxidic nitride.

Abstract: An improved semiconductor light emitting device having a stabilized lateral mode oscillation and device current.In the present invention, a current rejecting layer and an etch-back preventive layer are added to a semiconductor laser provided with a clad layer composed of a projecting portion for confining light from an active layer and a portion for passing the light. The thicknesses of the layers, the relationships of forbidden band widths of the layers and their conductivity type are all specified. An easily manufactured semiconductor laser with an excellent current limit function and optical guide function are obtained and the lateral mode oscillation oscillation is stable.

Abstract: A method for producing semiconductor laser elements from a wafer wherein the wafer is prepared having light emitting regions and then the wafer is scribed and cracked in order to form the semiconductor elements. The scribing is executed on a major surface of the wafer in such a way that scratches are formed along a separation line only on the surface of a crystal substrate of the wafer but not on the substrate over the formed light emitting regions. The cleaved surface developed by the cracking step is very flat in an area where the light emitting region is exposed to provide a mirror surface that forms a laser resonator. Desirably, the major surface of the wafer is covered with a protective film on at least the part of the surface over the light emitting region, prior to performing the scribe step. More desirably, this protective film consists of an electrode metal, such as Au or a resin, such as a photoresist material.