Patent ID: 8304267

Claim:
A fabrication method of a semiconductor laser comprising: coating a resist on a semiconductor layer; exposing a plurality of diffractive grating patterns to the resist, each pitch of each diffractive grating pattern being substantially the same, wherein only one diffractive grating pattern having a convex portion or a concave portion of an optical length is an odd multiple of half of one pitch of each of the other diffractive gratings; exposing a pattern having a plurality of space regions to the resist, the space region separating the diffractive grating pattern; and transferring a resist pattern formed by developing the resist to the semiconductor layer so as to form a first diffractive grating region and a second diffractive grating region, wherein the first diffractive grating region and the second diffractive grating region have a plurality of segments combined to each other each of the segments having a diffractive grating and a space region; and a segment to which the only one diffractive grating pattern is transferred is one of two segments of the first diffractive grating region or one of two segments of the second diffractive grating region that are on the boundary side between the first diffractive grating region and the second diffractive grating region.