A method to produce a semiconductor laser diode (LD) including a sampled grating (SG) is disclosed. The method prepares various resist patterns each including grating regions and space regions alternately arranged along an optical axis. The grating regions and the space region in respective cavity types have total widths same with the others but the grating regions in respective types has widths different from others. After the formation of the grating patterns based on the resist patterns, only one of the grating patterns is used for subsequent processes.