Patent ID: 7301979

Claim:
A semiconductor laser device, comprising: a first conductivity type cladding layer; an active layer; and a second conductivity type cladding layer, which are on a substrate, wherein the semiconductor laser device further comprises a stripe structure for injecting carriers therein, a width of the stripe is wider at a front end face of a resonator from which laser light is emitted than at a rear end face that is located on an opposite side of the front end face, a reflectance of the front end face is lower than a reflectance of the rear end face, a ratio between the stripe width at the front end face and the stripe width at the rear end face satisfies a relationship of 1<(the stripe width at the front end face)/(the stripe width at the rear end face)<2, the stripe structure has regions adjacent to the front end face and the rear end face, the regions respectively extending inwardly from the front end face and the rear end face and each having a constant swipe width, the region having the constant stripe width on the front end face side has a length of one-twentieth or shorter of a length of the resonator, and the region having the constant stripe width on the rear end face side has a length of one-twentieth or shorter of the length of the resonator, and the stripe width at the rear end face is 1.4 μm or more and less than 2.0 μm.