An optical waveguide includes opposed end sections for optical radiation to propagate in a longitudinal direction therebetween and an intermediate section extending between the end sections. The intermediate section includes first and second portions superposed in a superposition direction. One of the opposite end sections has a first height in the superposition direction corresponding to the sum of the heights of the superposed portions of the intermediate section. The other of the opposite end sections has a second height in the superposition direction corresponding to the height of the first of the superposed portions of the intermediate section.