Patent ID: 7609739

Claim:
A semiconductor laser device, comprising: an active layer having a single or multiple quantum well structure including a well layer of In w Ga 1-w N (0.08≦w≦0.2) and a barrier layer of In b Ga 1-b N (0.01≦b≦0.05); a cladding layer of Al y Ga 1-y N (0≦y≦0.1) provided on the active layer, the cladding layer including a ridge portion extending like a stripe in axial direction of an optical cavity and a non-ridge portion located on both sides of the ridge portion; and an overflow blocking layer of Al z Ga 1-z N (y<z) provided between the active layer and the cladding layer, a thickness of D (μm) of the non-ridge portion and an axial length of L (μm) of the optical cavity satisfying formulas L≧ 750−400×( D/ 0.01) and 0<D≦0.01, wherein a full width at half maximum of a horizontal far field pattern of a beam emitted from the active layer has a width of not less than 9.2 degrees.