A semiconductor laser includes a substrate; and a multilayered film formed
on the substrate and including an active layer. The multilayered film
includes a stripe structure that extends in a longitudinal direction of a
resonator and has a tapered portion in which a width of a stripe changes
in a tapered manner; and a first side face and a second side face that
sandwich the stripe structure. At least one side face of the first side
face and the second side face is inclined with respect to a principal
surface of the substrate.
