Optical coupling device

1. An integrated grating coupler/spot-size converter device for coupling a light beam into a waveguide, the device comprising:

a substrate; and

a grating portion arranged on the substrate having a plurality of essentially straight and essentially parallel scattering elements,

wherein two or more of the scattering elements have different lengths and arrangements in order to convert a spot-size of the light beam to match the size of the waveguide; and

wherein the scattering elements have a top side essentially opposite the substrate for receiving the light beam applied onto the scattering elements at a non-zero angle with respect to a plane of the grating portion.

2. The device of claim 1 , further comprising:

a waveguide portion next to the grating portion, wherein the waveguide portion and the grating portion are arranged in one plane.

3. The device of claim 2 , wherein the scattering elements of the grating portion are configured to capture electromagnetic waves of the light beam and convert the electromagnetic waves to a modal size corresponding to the waveguide.

4. The device of claim 1 , wherein the substrate comprises at least one dielectric layer.

5. The device of claim 1 , wherein one of the scattering elements has a width and at least one neighbouring scattering element has a different width.

6. The device of claim 1 , wherein at least one distance between neighbouring scattering elements is different from at least one other distance between neighbouring scattering elements.

7. The device of claim 1 , wherein a cross section dimension of the grating portion is larger than a cross section dimension of the light beam.

8. The device of claim 1 , wherein at least one front end of at least one scattering element is non-planar.