Edge coupler

Patent metadata

Field	Value
Publication number	US-9766408-B2
Application number	US-201715418246-A
Country	US
Kind code	B2
Filing date	Jan 27, 2017
Priority date	Jun 4, 2015
Publication date	Sep 19, 2017
Grant date	Sep 19, 2017

Abstract

A composite optical waveguide is constructed using an array of waveguide cores, in which one core is tapered to a larger dimension, so that all the cores are used as a composite input port, and the one larger core is used as an output port. In addition, transverse couplers can be fabricated in a similar fashion. The waveguide cores are preferably made of SiN. In some cases, a layer of SiN which is provided as an etch stop is used as at least one of the waveguide cores. The waveguide cores can be spaced away from a semiconductor layer so as to minimize loses.

First claim

What is claimed is:

1. A photonic integrated circuit (PIC) comprising:
a substrate;
an optical device layer supported over the substrate including a first waveguide; and
an edge coupler for coupling light between the first waveguide and a second waveguide, which includes a larger mode size than the first waveguide comprising:
a composite waveguide including a plurality of spaced apart waveguide cores capable of evanescent coupling therebetween supported over the substrate, outer ends of which extend proximate an edge of the PIC for optically coupling to the second waveguide enabling the transfer of the light between the second waveguide and the plurality of waveguide cores, and inner ends of the waveguide cores extend into the PIC; and
an optical input/output at the inner end of a first waveguide core of the plurality of waveguide cores capable of transferring light between the first waveguide core and the first waveguide.

2. The PIC according to claim 1 , wherein the first waveguide core includes an end section that expands towards the inner end thereof for increasing evanescent transfer of the light between the other of the plurality of waveguide cores and the first waveguide core.

3. The PIC according to claim 2 , wherein the first waveguide core is longer than the other of the plurality of waveguide cores.

4. The PIC according to claim 1 , wherein each of the plurality of waveguide cores other than the first waveguide core tapers down towards the inner end thereof.

5. The PIC according to claim 1 , wherein the first waveguide core is vertically spaced between the substrate and a second one of the plurality of waveguide cores, whereby the light travels towards or away from the substrate.

6. The PIC according to claim 5 , wherein the first waveguide core is laterally spaced from a third one of the plurality of waveguide cores.

7. The PIC according to claim 6 , wherein first and third waveguide cores are provided in a first stop layer of dielectric material; wherein the second waveguide core is provided in a second stop layer of dielectric material; and further comprising metallization between the first and second stop layers of dielectric material for electrically communicating with the optical device layer.

8. The PIC according to claim 1 , wherein the optical input/output is capable of evanescently transferring the light between the first waveguide and the composite waveguide.

9. The PIC according to claim 1 , wherein the optical device layer is between the composite waveguide and the substrate.

10. The PIC according to claim 1 , further comprising index matching material on an upper surface of the PIC for enclosing the larger mode from the second waveguide.

11. The PIC according to claim 1 , wherein the optical device layer includes a laser for generating the light for output the composite waveguide to the second waveguide.

12. The PIC according to claim 1 , wherein the optical device layer includes a photodetector for receiving the light from the second waveguide via the composite waveguide.

13. The PIC according to claim 1 , wherein the composite waveguide is capable of converting the mode size of the light between less than 1 μm and greater than 5 μm.

14. The PIC according to claim 1 , wherein the composite waveguide is capable of converting the mode size of the light between less than 1 μm and about 10 μm.

15. The PIC according to claim 1 , wherein the outer end of each waveguide core includes a width of less than 1 micron and a thickness of less than 1 micron.

16. The PIC according to claim 1 , wherein each waveguide core includes a thickness of about 120 nm.

17. The PIC according to claim 1 , wherein the end section of the first waveguide core includes a width that expands from about 300 nm to about 1 μm.

18. The PIC according to claim 1 , wherein each waveguide core comprises a dielectric or semiconductor material enabling illumination of a desired wavelength; and
wherein the semiconductor or dielectric material is selected from the group consisting of crystalline silicon, poly-silicon, amorphous silicon, silicon nitride, silicon oxynitride, silicon dioxide, doped silicon dioxide, and a polymer.

19. A method of manufacturing a photonic integrated circuit (PIC) comprising:
providing an optical device layer including a first waveguide on a substrate;
depositing a first stop layer;
depositing a metal layer;
depositing a second stop layer; and
patterning the first and second stop layers into a plurality of waveguide cores forming an edge coupler for coupling light between the first waveguide and a second waveguide with a larger mode size than the first waveguide, the edge coupler comprising:
a composite waveguide including the plurality of spaced apart waveguide cores capable of evanescent coupling therebetween, outer ends of which extends to an edge of the PIC for optically coupling to the second waveguide enabling the transfer of light between the second waveguide and the plurality of waveguide cores, and inner ends of which extend into the PIC; and
an optical input/output at the inner end of a first waveguide core of the plurality of waveguide cores for transferring the light between the first waveguide and the composite waveguide.

20. The method according to claim 19 , wherein a first waveguide core of the plurality of waveguide cores includes an end section that expands towards the inner end thereof for increasing evanescent transfer of light between the other of the plurality of waveguide cores and the first one of the plurality of waveguide cores.

Assignees

• Elenion Tech Llc

Inventors

• Novack Ari
• Shi Ruizhi
• Hochberg Michael J
• Baehr-Jones Thomas

Classifications

• G02B6/125

  Bends, branchings or intersections · CPC title

• G02B6/132

  by deposition of thin films · CPC title

• G02B6/1228

  Tapered waveguides, e.g. integrated spot-size transformers (for coupling with fibres G02B6/305) · CPC title

• G02B6/305 Primary

  and having an integrated mode-size expanding section, e.g. tapered waveguide · CPC title

• G02B6/14

  Mode converters · CPC title