Patent ID: 6885085

Claim:
A semiconductor laser device having a first-conductivity-type first cladding layer, an active layer, and a second-conductivity-type second cladding layer supported by a first-conductivity-type GaAs substrate and formed in this order, each of said layers comprising a III-V-group compound semiconductor, the active layer having at least one well layer and barrier layers having an energy bandgap larger than the well layer, the well layer being interposed between the barrier layers, wherein the well layer and the barrier layers each include P and As as V-group elements and Ga and In as III-group elements; a proportion of P in the V-group elements in the barrier layers is larger than a proportion of P in the V-group elements in the well layer; a proportion of In in the III-group elements in the barrier layers is smaller than a proportion of In in the III-group elements in the well layer; the barrier layers have a tensile strain with respect to the GaAs substrate; the well layer has a compressive strain with respect to the GaAs substrate; and the semiconductor laser device has an emission wavelength of approx. 780 nm.