Passive alignment of polymer waveguides

1. A chip packaging comprising a first part and a second part, wherein

the first part comprises:

a support; and

a core polymer layer extending over an inner region and an outer region of the support, the core polymer layer transversally structured so as to exhibit distinct residual portions, each having a same first height, which corresponds to a thickness of the core polymer layer, the residual portions comprising:

first waveguide cores disposed within said inner region; and

one or more first alignment structures disposed within said outer region,

the second part comprises:

second waveguide cores, each having a same second height; and

one or more second alignment structures complementarily shaped with respect to the one or more first alignment structures,

wherein the first part is structured such that said inner region is recessed with respect to the outer region, to enable:

the second waveguide cores to contact the first waveguide cores; and

the one or more second alignment structures to respectively receive, at least partly, the one or more first alignment structures;

and wherein the inner region and the outer region are each planar and structurally contiguous.

2. The chip packaging of claim 1 , wherein the first part is structured such that a top surface of the one or more first alignment structures lies in a first plane and a top surface of the first waveguide cores lies in a second plane, parallel to and at a distance from the first plane, said distance larger than the sum of said first height and said second height.

3. The chip packaging of claim 1 , wherein the support comprises a support and a polymer cladding layer extending over the support, said inner region defined on the polymer cladding layer.

4. The chip packaging of claim 1 , wherein the support is a deformable support, shaped so as for said inner region to be recessed with respect to the outer region.

5. The chip packaging of claim 3 , wherein the core polymer layer extends over the polymer cladding layer, said inner region and outer region being, each, defined directly on the polymer cladding layer.

6. The chip packaging of claim 1 , wherein the chip packaging is a silicon photonics chip packaging, the second part is a silicon photonics chip and the second waveguide cores are silicon-on insulator waveguide cores.

7. The chip packaging of claim 1 , wherein the first waveguide cores extend parallel to each other and the second waveguide cores extend parallel to each other.

8. The chip packaging of claim 7 , wherein the first waveguide cores and the second waveguide cores are configured so as to enable an adiabatic coupling between the first waveguide cores and the second waveguide cores.

9. The chip packaging of claim 8 , wherein each of the second waveguide cores exhibits a tapered portion.

10. The chip packaging of claim 1 , wherein each of the one or more first alignment structures are longitudinal structures at least partly inserted into the one or more second alignment structures.

11. The chip packaging of claim 10 , wherein the chip packaging comprises at least two first alignment structures and at least two second alignment structures.

12. The chip packaging of claim 1 , wherein the second part comprises a silicon support with a buried oxide layer.

13. The chip packaging of claim 12 , wherein the one or more second alignment structures are provided as cavities open at the level of the buried oxide layer and extending into a thickness of the silicon support.

14. A method for passively aligning two parts of a chip packaging, the method comprising:

providing a first part and a second part of a chip packaging, wherein:

the first part comprises:

a deformable support; and

a core polymer layer extending over an inner region and an outer region of the deformable support, the core polymer layer transversally structured so as to exhibit distinct residual portions, each having a same first height, which corresponds to a thickness of the core polymer layer, the residual portions comprising:

first waveguide cores disposed within said inner region; and

one or more first alignment structures disposed within said outer region, and

the second part comprises:

second waveguide cores, each having a same second height; and

one or more second alignment structures complementarily shaped with respect to the one or more first alignment structures,

shaping the deformable support such that the inner region and the outer region are each planar and structurally contiguous and the inner region is recessed with respect to the outer region, and

bringing together the first part and the second part such that the second waveguide cores respectively contact the first waveguide cores and the one or more second alignment structures respectively receive, at least partly, the one or more first alignment structures.

15. The method of claim 14 , wherein shaping the deformable support is carried out using a pre-formed vacuum chuck with a recess vis-à-vis the inner region, so as to obtain the inner region recessed with respect to the outer region.

16. The method of claim 14 , wherein providing the first part and the second part of the chip packaging comprises fabricating the core polymer layer by depositing the core polymer layer onto the support and curing the core polymer layer.

17. The method of claim 14 , wherein the method further comprises, prior to providing said first part and said second part, fabricating the transversally structured core polymer layer by patterning said first waveguide cores and said one or more first alignment structures, during a same patterning process step.

18. A method for passively aligning two parts of a chip packaging, the method comprising:

providing a first part and a second part of a chip packaging, wherein:

the first part comprises:

a support; and

a core polymer layer extending over an inner region and an outer region of the support, the core polymer layer transversally structured so as to exhibit distinct residual portions, each having a same first height, which corresponds to a thickness of the core polymer layer, the residual portions comprising:

first waveguide cores disposed within said inner region; and

one or more first alignment structures disposed within said outer region,

the second part comprises:

second waveguide cores, each having a same second height; and

one or more second alignment structures complementarily shaped with respect to the one or more first alignment structures,

and wherein, the first part is structured such that

said inner region is recessed with respect to the outer region, to enable

the second waveguide cores to contact the first waveguide cores and

the one or more second alignment structures to respectively receive, at least partly, the one or more first alignment structures, to enable a passive alignment of the two parts,

bringing together the first part and the second part such that

the inner region and the outer region are each planar and structurally contiguous,

the second waveguide cores respectively contact the first waveguide cores and

the one or more second alignment structures respectively receive, at least partly, the one or more first alignment structures.