US Patent 7474682 Semiconductor laser device and laser projector

In a semiconductor laser device (10) having different facet reflectivities, an electrode disposed on a stripe ridge (107a) is divided into four electrode parts (1), (2), (3), and (4), and a larger injection current is injected to an electrode part that is closer to a light emission facet side. Further, a carrier density distribution in an active layer that is opposed to the stripe ridge can be matched to a light intensity distribution in the active layer, thereby preventing degradation in high output characteristic due to destabilization of a transverse mode and reduction in gain which are caused by spatial hole burning.