There is provided an optoelectronic device including: first and second optical waveguides arranged on a bulk silicon substrate to be spaced apart from each other in a first direction parallel to an upper surface of the bulk silicon substrate; and an active region interposed between the first and second optical waveguides on the bulk silicon substrate such that one side of the active region contacts the first optical waveguide and the other side contacts the second optical waveguide portion, wherein the first and second optical waveguides and the active region include germanium-silicon (GeSi) alloy.