Semiconductor laser device

A semiconductor laser device comprising:

• an n-type substrate;
• a semiconductor laminated section in which an n-type cladding layer, an active layer, and a p-type cladding layer are sequentially laminated on the n-type substrate;
• and
• a stripe structure on an upper section of the semiconductor laminated section,
• wherein the n-type cladding layer has at least two layers that are:
• a first n-type cladding layer configured of an Alx1Ga1-x1As layer (0.4<x1≤1), at a side distant from the active layer;
• and
• a second n-type cladding layer configured of an (Alx2Ga1-x2)1-y2Iny2P layer (0≤x2≤1, 0.45≤y2≤0.55), at a side near to the active layer,
• the p-type cladding layer is configured of an (Alx3Ga1-x3)1-y3Iny3P layer (0≤x3≤1, 0.45≤y3≤0.55), and
• a width of the stripe structure is 10 μm or more, and a refractive index with respect to a laser oscillation wavelength of the first n-type cladding layer is less than or equal to a refractive index with respect to a laser oscillation wavelength of the second n-type cladding layer.