A method for optical coupling an optical waveguide to an optical unit arranged in or on an optical module, a corresponding optical module, coupling element, and a kit of coupling elements is provided. The optical module has a reference geometry which defines a first axis of symmetry. Any offset between a first optical axis of the optical unit and the axis of symmetry of the reference geometry is determined. A coupling element corrects the offset and has an input/output area on opposite faces having offset second and third optical axes. Light input along the second optical axis is guided in the coupling element and output along the third optical axis, and vice versa. Once assembled, the center axis of the coupling element coincides with the axis of symmetry of the optical module, and the first optical axis of the optical unit and second optical axis of the coupling element coincide.