Patent ID: 7978744

Claim:
A nitride based semiconductor laser device comprising: a nitride based semiconductor layer having an optical waveguide extending in a substantial [0001] direction and having one facet composed of a substantial (0001) plane and the other facet composed of a substantial (000 1 ) plane as a pair of cavity facets; a first protective film provided on said one facet and including nitrogen as a constituent element; and a dielectric multilayer film including a second protective film provided on said other facet and including oxygen as a constituent element, wherein the intensity of laser light emitted from said one facet is higher than the intensity of laser light emitted from said other facet, and said dielectric multilayer film includes a first oxide film, an oxynitride film, and a second oxide film that are laminated in this order from said other facet, the nitrogen composition ratio is higher than the oxygen composition ratio in said oxnitride film, and said second protective film is said first oxide film.