The present invention relates to an apparatus for optical applications, a spectrometer system and method for producing an apparatus for optical applications, and in particular to an apparatus comprising an optical waveguide having a first refractive index along a light propagation axis interrupted by a plurality of scattering portions having a second refractive index. Each scattering portion has a long axis substantially perpendicular to the light propagation axis as well as a short axis substantially perpendicular to the light propagation axis and the long axis. A receiver unit or a transmitter unit is arranged on a side of the optical waveguide, the long axis being substantially perpendicular, i.e. normal to the plane of this side on which the receiver unit or transmitter unit is arranged. Accordingly, simplification and miniaturization of an optical apparatus can be realized.