Electro-optical device with ring resonator

Patent metadata

Field	Value
Publication number	US-12140799-B2
Application number	US-202117476152-A
Country	US
Kind code	B2
Filing date	Sep 15, 2021
Priority date	Dec 20, 2018
Publication date	Nov 12, 2024
Grant date	Nov 12, 2024

Abstract

A ring resonator electro-optical device includes a first silicon nitride waveguide and a second annular silicon waveguide that comprises a first section running under a second section of the first waveguide. The second waveguide also includes an annular silicon strip having a cross-section increasing in the first section from a minimum cross-section located under the second section.

First claim

What is claimed is:

1. A ring resonator electro-optical device comprising:
a first annular silicon waveguide comprising a first annular silicon strip; and
a second silicon waveguide located at a same level of the device as the first annular silicon waveguide and comprises a second silicon strip arranged at a distance from the first annular silicon strip, wherein a first lateral edge of the second silicon strip is bordered by a first silicon slab and a second lateral edge of the second silicon strip is bordered by a second silicon slab.

2. The device of claim 1 , wherein the second silicon strip has a constant cross-section.

3. The device of claim 1 , wherein the first annular silicon waveguide is configured to have a shape of an oval or athletics track.

4. The device of claim 1 , further comprising a first silicon nitride waveguide optically coupled to the first annular silicon waveguide, the first silicon nitride being arranged at a lower level of the device than the first annular silicon waveguide.

5. The device of claim 4 , wherein a first section of the first annular silicon waveguide and a second section of the first silicon nitride waveguide overlap and a cross-section of the first annular silicon strip increases from a minimum cross-section located in a plane that is substantially orthogonal to a longitudinal direction of the second section.

6. The device of claim 5 , wherein at least along an entire length of the first section an outer lateral edge of the first annular silicon strip follows a circle and an inner lateral edge of the first annular silicon strip follows an ellipse.

7. The device of claim 5 , wherein, at a location of the minimum cross-section, a distance between the first section and the second section is shorter than 150 nm.

8. The device of claim 5 , wherein beyond the first section, a third silicon slab borders an inner lateral edge or an outer lateral edge of a longitudinal portion of the first annular silicon strip, or the third silicon slab borders the inner lateral edge and a fourth silicon slab borders the outer lateral edge of the longitudinal portion of the first annular silicon strip.

9. The device of claim 5 , wherein the first annular silicon waveguide and the first silicon nitride waveguide are configured to guide a given optical mode, the minimum cross-section having dimensions such that, in the plane comprising the minimum cross-section, effective optical indexes of the optical mode in the second and third waveguides are equal, to within more or less 0.1.

10. A ring resonator electro-optical device comprising:
a first annular silicon waveguide comprising a first annular silicon strip;
a second silicon waveguide located at a same level of the device of the first annular silicon strip, the second silicon waveguide comprising a second silicon strip;
a first silicon slab bordering an inner lateral edge of a longitudinal portion of the first annular silicon strip beyond a first section of the first annular silicon strip;
a second silicon slab bordering an outer lateral edge of the longitudinal portion of the first annular silicon strip beyond the first section of the first annular silicon strip;
a third silicon slab bordering an inner lateral edge of the second silicon strip; and
a fourth silicon slab bordering an outer lateral edge of the second silicon strip.

11. The device of claim 10 , wherein the second silicon slab and the third silicon slab share a common portion.

12. The device of claim 11 , wherein the common portion is undoped.

13. The device of claim 10 , wherein the first silicon slab bordering the inner lateral edge of the longitudinal portion of the first annular silicon strip is doped with a first conductivity type and the second silicon slab bordering the outer lateral edge of the longitudinal portion of the first annular silicon strip is doped with a second conductivity type.

14. The device of claim 13 , wherein the longitudinal portion of the first annular silicon strip is undoped.

15. The device of claim 13 , wherein the longitudinal portion of the first annular silicon strip is successively doped with the first conductivity type on the side of the first silicon slab doped with the first conductivity type, non-doped, and doped with the second conductivity type on the side of the second silicon slab doped with the second conductivity type.

16. The device of claim 13 , wherein the longitudinal portion of the first annular silicon strip is successively doped with the first conductivity type on the side of the first silicon slab doped with the first conductivity type and doped with the second conductivity type on the side of the second silicon slab doped with the second conductivity type.

17. The device of claim 10 , wherein the longitudinal portion of the first annular silicon strip comprises, lengthwise, a first doped region of a first conductivity type and a second doped region of a second conductivity type.

18. The device of claim 17 , wherein the first doped region is separated from the second doped region by a non-doped region of the longitudinal portion of the first annular silicon strip.

19. The device of claim 17 , wherein the first and second regions continue in the first silicon slab bordering the portion of the first annular silicon strip, the first and second regions being arranged on the side of the inner lateral edge of the portion of the annular strip.

20. An optical device comprising:
a ring resonator electro-optical device that comprises:
a first silicon annular waveguide having an oval or athletic track shape; and
a second silicon waveguide located at a same level of the device as the first annular silicon waveguide, the second silicon waveguide comprising first silicon strip, wherein an inner lateral edge of the first silicon strip is bordered by a first silicon slab and an outer lateral edge of the first silicon strip is bordered by a second silicon slab.

21. The optical device of claim 20 , wherein the first silicon annular waveguide comprises a second annular silicon strip, and the device further comprises a third silicon slab bordering an inner lateral edge of a longitudinal portion of the annular silicon strip beyond a first section of the second annular silicon strip, and a fourth silicon slab bordering an outer lateral edge of the longitudinal portion of the second annular silicon strip beyond the first section of the second annular silicon strip.

22. The optical device of claim 21 , wherein the first silicon slab and the fourth silicon slab share an undoped common portion.

Assignees

• St Microelectronics Crolles 2 Sas

Inventors

• Le Maitre Patrick
• Michit Nicolas

Classifications

• G02F2203/15

  involving resonance effects, e.g. resonantly enhanced interaction · CPC title

• G02F1/225

  in an optical waveguide structure · CPC title

• G02B2006/12061

  Silicon · CPC title

• G02B6/12007

  forming wavelength selective elements, e.g. multiplexer, demultiplexer · CPC title

• G02F1/3132

  of directional coupler type · CPC title