A semiconductor laser has a first conduction-type cladding layer, an active layer,
and a second conduction-type cladding layer formed on a first conduction-type semiconductor
substrate. The second conduction-type cladding layer has a mesa-type stripe-shaped
recessed portion in at least four spots, so as to form a central ridge portion,
which constitutes a ridge-type current confinement portion, and two or more lateral
ridge portions, which are positioned on both sides of the central ridge portion,
have a height larger than to that of the central ridge portion, and include the
second conduction-type cladding layer. An insulation film with a lower refractive
index than the second conduction-type cladding layer is formed in a pair of stripes
disposed respectively in the regions from the side surface of the second conduction-type
cladding layer on both side surfaces of the central ridge portion toward the outside.
The insulation film is not formed on the central ridge portion.
