A GaAlAs semiconductor laser element includes a Ga1-xAlxAs active layer sandwiched by a first and second Ga1-yAlyAs cladding layers. A Ga1-zAlzAs substrate layer supports the first cladding layer, and a Ga1-zAlzAs cap layer covers the second cladding layer. The AlAs mole fraction (z) of the substrate layer and the cap layer is selected slightly smaller than the AlAs mole fraction (x) of the active layer. Further, the active layer is located in the laser element so that the active layer is separated from the mounted surface by more than 35% of the laser element thickness, and is separated from the opposing surface by more than 18% of the laser element thickness.
