A configuration for coupling optical signals of at least one optical data channel into and/or out of an optical waveguide carrying optical signals of at least two optical data channels includes at least two optical waveguide sections forming the optical waveguide, the sections positioned axially one behind the other, at least core regions of two optical waveguide sections being positioned one behind the other separated from one another by a free-radiating region, an end face of at least one waveguide section running obliquely with respect to an optical axis (7) of the waveguide and being coated with a wavelength-selective filter, and, for a specific optical data channel, light being coupled into or out of the optical waveguide by reflecting light of the optical data channel, before or after traversing the free-radiating region, at the end face of the optical waveguide section running obliquely with respect to the optical axis.