Semiconductor laser device and optical pickup apparatus using the same

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
• the semiconductor laser device has a region in which a width of the stripe decreases continuously from a front end face to a rear end face, a difference between L1 and Lt is within 200 μm, and Rf<Rr, where L1 is a distance from the front end face to a position at which the width of the stripe is minimal in the region in which the width of the stripe decreases continuously, 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 the rear end face, and Lt is a distance expressed by L×Loge(Rf)/Loge(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.