Patent ID: 8923355

Claim:
A semiconductor laser device, comprising: an n-type clad layer; a first p-type clad layer; a ridge stripe including a second p-type clad layer formed into a ridge stripe shape on the opposite surface of the first p-type clad layer from the n-type clad layer; an active layer interposed between the n-type clad layer and the first p-type clad layer; and a current-blocking layer formed on side surfaces of the ridge stripe, the ridge stripe being formed such that a first ridge width as the width of a surface of the second p-type clad layer exists on the same side as the first p-type clad layer and a second ridge width as the width of a surface of the second p-type clad layer exists at the opposite side from the first p-type clad layer, the first ridge width being not less than 3.0 μm and not greater than 4.5 μm, and the second ridge width being not less than 2.0 μm, the active layer generating a tensile strain, the semiconductor laser device being configured to oscillate in a TM mode, in response to the ridge stripe being formed, the active layer comprising a GaAs (1-x3) P x3 well layer, where 0≦x3≦1, and the n-type clad layer, the first p-type clad layer and the second p-type clad layer formed of a (Al x1 Ga (1-x1) ) 0.51 In 0.49 P layer that has a composition where 0≦x1≦1.