Method and spacer for assembling flexible optical waveguide ribbons, and assembled stack of such ribbons

1. A method for assembling flexible optical waveguide ribbons, the method comprising steps of:

providing a ribbon stack comprising at least two optical waveguide ribbons stacked onto each other, and a spacer having a hollow space configured to receive a portion of said ribbon stack and a plurality of calibrated spaces extending through a side wall of said spacer, each of said plurality of calibrated spaces configured to receive a free-standing portion of each of said optical waveguide ribbons, wherein said plurality of calibrated spaces are defined by a plurality of tongues having first ends aligned with said side wall of said spacer and second ends that are opposite to said first ends vertically aligned with each other;

positioning said ribbon stack in said hollow space of said spacer;

constraining positioned ribbon stack in said plurality of calibrated spaces by receiving said free-standing portion of each of said optical waveguide ribbons in a respective one of said plurality of calibrated spaces, a portion of said free-standing portion of each of said optical waveguide ribbons located outside said side wall of said spacer; and

fixing constrained ribbon stack in said plurality of calibrated spaces.

2. The method according to claim 1 , wherein said optical waveguide ribbons are fixed by an adhesive in said spacer.

3. The method according to claim 2 , wherein said step of constraining further comprises the step of:

filling said adhesive in said spacer.

4. The method according to claim 1 , further comprising the steps of:

providing said free-standing portion at one end of each optical waveguide ribbon, wherein said spacer comprises a plurality of recesses that defines respective said calibrated spaces;

inserting each of said free-standing portions in said respective one of said plurality of recesses; and

fixing said constrained ribbon stack in said respective one of said plurality of recesses.

5. The method according to claim 4 , wherein each of said optical waveguide ribbons further comprises a substrate and a cladding present on the substrate, the method further comprising a step of:

preparing each of said free-standing portions by partially removing or delaminating said substrate at said one end of each of said optical waveguide ribbons from a side of said substrate opposite to said cladding, wherein optical waveguides are arranged in said cladding, and wherein a top surface of each of said free-standing portions is coplanar with a top surface of said cladding and said bottom surface of each of said free-standing portions is located above a bottom surface of said substrate at another end of each of said optical waveguide ribbons.

6. The method according to claim 5 , further comprising a step of:

cutting said portion of said free-standing portion of each optical waveguide ribbon located outside said side wall of said spacer.

7. The method according to claim 6 , wherein said spacer is provided as a ferrule with through hole recesses integrated therein.

8. The method according to claim 1 , wherein said spacer comprises a receptacle and a spacer element.

9. The method according to claim 8 , wherein said step of constraining further comprises the steps of:

exposing said positioned ribbon stack to an adhesive; and

curing said adhesive.

10. The method according to claim 9 , wherein said step of constraining further comprises the step of:

irradiating said adhesive through said spacer element.

11. The method according to claim 1 , wherein said spacer is calibrated so that a tolerance in positioning, after fixing, one of said optical waveguide ribbons is less than ±10 μm.

12. The method according to claim 1 , wherein:

an assembled stack of flexible optical waveguide ribbons is obtained; and

each of ribbon end sections at an end section of said assembled stack is calibrated in a respective calibrated section.

13. The method according to claim 12 , wherein an optical connector comprises said assembled stack.

14. The method according to claim 1 , wherein each of said plurality of tongues has a flat top surface and a curved bottom surface, said flat top surface of one of said plurality of tongues and said curved bottom surface of adjacent one of said plurality of tongues defining one of said plurality of calibrated spaces.

15. The method according to claim 14 , wherein said flat top surface of each of said plurality of tongues contacts a bottom surface of another portion of said free-standing portion of each of said optical waveguide ribbons.

16. A device for assembling flexible optical waveguide ribbons, comprising:

a spacer having a hollow space configured to receive a portion of a ribbon stack comprising at least two optical waveguide ribbons and a plurality of calibrated spaces extending through a side wall of said spacer, each of said plurality of calibrated spaces configured to receive a free-standing portion of each of said optical waveguide ribbons, wherein said plurality of calibrated spaces are defined by a plurality of tongues having first ends aligned with said side wall of said spacer and second ends that are opposite to said first ends vertically aligned with each other;

said spacer is configured to allow:

positioning of optical waveguide ribbons in said hollow space of said spacer;

constraining of each of said optical waveguide ribbons in a respective one of said plurality of calibrated spaces by receiving said free-standing portion of each of said optical waveguide ribbons in said respective one of said plurality of calibrated spaces, a portion of said free-standing portion of each of said optical waveguide ribbons located outside said side wall of said spacer; and

fixing of said optical waveguide ribbons.

17. The device according to claim 16 , wherein said plurality of tongues are arranged substantially parallel to each other.

18. The device according to claim 16 , wherein each of said plurality of tongues has a flat top surface and a curved bottom surface, said flat top surface of one of said plurality of tongues and said curved bottom surface of adjacent one of said plurality of tongues defining one of said plurality of calibrated spaces.

19. The device according to claim 18 , wherein said flat top surface of each of said plurality of tongues contacts a bottom surface of another portion of said free-standing portion of each of said optical waveguide ribbons.