A semiconductor laser includes a substrate, a double hetero structure portion
formed
on the substrate, the double hetero structure including a first clad layer formed
on the substrate, an active layer formed on the first clad layer and a second clad
layer formed on the active layer, the second clad layer having a stripe-form projection
on an upper surface thereof, the projection having an upper portion whose sidewalls
are substantially vertically formed on the surface of the substrate and a step-shaped
lower portion whose line width is larger than that of the upper portion, and a
current blocking layer formed extending from side surfaces of the projection to
the upper surface of the second clad layer except an upper surface of the projection.
