A distributed feedback semiconductor laser oscillating in a single mode and a method for manufacturing the same is disclosed. The distributed feedback semiconductor laser includes an active layer; a clad layer formed adjacent to the active layer; and diffraction gratings periodically formed in the clad layer and separated from each other by a predetermined distance. The diffraction gratings are formed of a nonconductor so that a current injected into the active layer is partially blocked and distribution of gain coefficient is varied. The nonconductor is an oxidized semiconductor material.