Provided is an optical array device including a substrate, an optical waveguide input section extending in a first direction on the substrate, a cladding surrounding the optical waveguide input section and separating the substrate and the optical waveguide input section from each other on the substrate, and a stray light blocking pattern covering the cladding, wherein a lowermost surface of the stray light blocking pattern may be located at a lower level than a lowermost surface of the optical waveguide input section.