Patent ID: 7257139

Claim:
A semiconductor laser device having a striped structure for injecting carriers, comprising: a first electrically-conductive cladding layer; an active layer; and a second electrically-conductive cladding layer; wherein the first electrically-conductive cladding layer, the active layer and the second electrically-conductive cladding layer are formed on a substrate, and a width of the stripe changes along a resonator direction, a difference between L1 and Lt is within 200 μm, and Rf<Rr, where L1 is a distance from a front end face to a position at which the width of the stripe is minimal, L is a length of a resonator of the semiconductor laser device, Rf is a reflectivity of the front end face, Rr is a reflectivity of a rear end face, and Lt is a distance expressed by L×Log e (Rf)/Log e (Rf×Rr), a width of the stripe at the rear end face is smaller than a width of the stripe at the front end face, and the width of the stripe at the rear end face ranges from 1.6 μm to 2.6 μm.