US Patent 7792172 Nitride semiconductor laser device

A nitride semiconductor laser device has a multilayer structure formed by stacking a plurality of nitride semiconductor layers made of hexagonal nitride semiconductors, while the multilayer structure is provided with a waveguide structure for guiding a laser beam, the nitride semiconductor layers forming the multilayer structure are stacked in a direction substantially perpendicular to the c-axes of the hexagonal nitride semiconductors constituting the nitride semiconductor layers, a first cavity facet forming a side surface of the waveguide structure is a c-plane having Ga-polarity, a second cavity facet forming another side surface of the waveguide structure opposed to the first cavity facet is a c-plane having N-polarity, a crystalline nitrogen-containing film is formed on the surface of the first cavity facet, and the reflectance of the first cavity facet is smaller than the reflectance of the second cavity facet.