In a semiconductor laser device, a plurality of light-emitting elements
emitting light with different wavelengths are integrated on a substrate.
Each of the light-emitting elements includes, on the substrate, an active
layer and cladding layers respectively provided on top and bottom of the
active layer. One of the cladding layers provided on top of the active
layer is an upper cladding layer having a mesa ridge portion. An etching
stopper layer for forming the ridge portion is interposed between the
ridge portion and the other portion of the upper cladding layer. The
thickness of the etching stopper layer varies among the light-emitting
elements.