Systems and methods for coupling light into a multi-mode resonator

Patent metadata

Field	Value
Publication number	US-11209597-B2
Application number	US-202016844272-A
Country	US
Kind code	B2
Filing date	Apr 9, 2020
Priority date	Apr 10, 2019
Publication date	Dec 28, 2021
Grant date	Dec 28, 2021

Abstract

A photonic system includes a passive optical cavity and an optical waveguide. The passive optical cavity has a preferred radial mode for light propagation within the passive optical cavity. The preferred radial mode has a unique light propagation constant within the passive optical cavity. The optical waveguide is configured to extend past the passive optical cavity such that at least some light propagating through the optical waveguide will evanescently couple into the passive optical cavity. The passive optical cavity and the optical waveguide are collectively configured such that a light propagation constant of the optical waveguide substantially matches the unique light propagation constant of the preferred radial mode within the passive optical cavity.

First claim

What is claimed is:

1. A photonic system, comprising:
a passive optical cavity having a preferred radial mode for light propagation within the passive optical cavity, the preferred radial mode having a unique light propagation constant within the passive optical cavity; and
an optical waveguide configured to extend past the passive optical cavity such that at least some light propagating through the optical waveguide will evanescently couple into the passive optical cavity, the passive optical cavity and the optical waveguide collectively configured such that a light propagation constant of the optical waveguide substantially matches the unique light propagation constant of the preferred radial mode within the passive optical cavity.

2. The photonic system as recited in claim 1 , wherein the passive optical cavity includes a curved section having an outer wall defined by an outer radius, an inner wall defined by an inner radius, and a radial width measured as the outer radius minus the inner radius.

3. The photonic system as recited in claim 2 , wherein the radial width of the curved section of the passive optical cavity is within a range extending from about 500 nanometers to about 3 micrometers.

4. The photonic system as recited in claim 2 , wherein the radial width of the curved section of the passive optical cavity is large enough to support multiple radial modes of light propagation within the passive optical cavity, wherein the preferred radial mode is one of the multiple radial modes, and wherein the preferred radial mode is a fundamental mode or a lowest order mode having a radius of maximum energy density closest to the outer wall relative to others of the multiple radial modes.

5. The photonic system as recited in claim 2 , wherein the optical waveguide has a first wall, a second wall, and a width measured perpendicularly between the first wall and the second wall, the first wall positioned closest to the passive optical cavity.

6. The photonic system as recited in claim 5 , wherein the radial width of the curved section of the passive optical cavity is greater than or equal to two times the width of the optical waveguide.

7. The photonic system as recited in claim 6 , wherein the width of the optical waveguide is within a range extending from about 250 nanometers to about 650 nanometers.

8. The photonic system as recited in claim 5 , further comprising:
a cladding material disposed around and between the passive optical cavity and the optical waveguide, the cladding material having an optical refractive index different than each of an optical refractive index of the passive optical cavity and an optical refractive index of the optical waveguide.

9. The photonic system as recited in claim 8 , wherein the radial width of the curved section of the passive optical cavity is greater than λ/√{square root over (n core 2 −n clad 2 )}, wherein λ is a free-space wavelength of light corresponding to the preferred radial mode within the passive optical cavity, n core is the optical refractive index of the passive optical cavity, and n clad is the optical refractive index of the cladding material.

10. The photonic system as recited in claim 9 , wherein the wavelength of light corresponding to the preferred radial mode within the passive optical cavity is within a range extending from about 1260 nanometers to about 1310 nanometers.

11. The photonic system as recited in claim 5 , wherein the optical waveguide has a vertical thickness as measured parallel to the first wall and the second wall within a range extending from about 30 nanometers to about 500 nanometers.

12. The photonic system as recited in claim 5 , wherein the first wall of the optical waveguide has a curvature that substantially matches a curvature of the outer wall of the curved section of the passive optical cavity along an optical coupling region when viewed in a horizontal cross-section oriented perpendicular to a centerline axis of the passive optical cavity.

13. The photonic system as recited in claim 12 , wherein the passive optical cavity is annular shaped with the outer wall forming a circle within the horizontal cross-section, the optical coupling region extending around about one-tenth to about one-quarter of a circumference of the outer wall of the passive optical cavity.

14. The photonic system as recited in claim 5 , wherein the first wall of the optical waveguide has a curvature that tangentially approaches a curvature of the outer wall of the curved section of the passive optical cavity along an optical coupling region when viewed in a horizontal cross-section oriented perpendicular to a centerline axis of the passive optical cavity, such that a minimum separation distance exists at a single location between the first wall of the optical waveguide and the outer wall of the curved section of the passive optical cavity.

15. The photonic system as recited in claim 14 , wherein the passive optical cavity is annular shaped with the outer wall forming a circle within the horizontal cross-section, the optical coupling region extending around about one-tenth to about one-quarter of a circumference of the outer wall of the passive optical cavity.

16. The photonic system as recited in claim 14 , wherein the minimum separation distance between the outer wall of the curved section of the passive optical cavity and the first wall of the optical waveguide is within a range extending from about 100 nanometers to about 350 nanometers.

17. The photonic system as recited in claim 2 , wherein the passive optical cavity is annular-shaped with the curved section extending continuously around the passive optical cavity.

18. The photonic system as recited in claim 1 , wherein the passive optical cavity and the optical waveguide are formed of one or more of monocrystalline silicon, polycrystalline silicon, amorphous silicon, silica, glass, silicon nitride, silicon dioxide, germanium oxide, and III-V material.

19. The photonic system as recited in claim 18 , further comprising:
a cladding material disposed around and between the passive optical cavity and the optical waveguide, wherein the cladding material is formed of one or more of silicon dioxide and silicon nitride, so long as the cladding material has an optical refractive index different than each of an optical refractive index of the passive optical cavity and an optical refractive index of the optical waveguide.

20. A photonic system, comprising:
a ring resonator having a passive optical cavity, the passive optical cavity having a circuitous configuration, the passive optical cavity having an outer wall, a top surface, and a bottom surface, the passive optical cavity having a curved portion, the outer wall of the curved portion having a first radius of curvature, the ring resonator configured to support multiple radial modes of light propagation within the passive optical cavity, the passive optical cavity having a preferred radial segment through which a preferred radial mode of light propagates within the passive optical cavity, the preferred radial segment having a first light propagation constant; and
an optical waveguide configured to extend past the passive optical cavity of the ring resonator, the optical waveguide having an outer wall farthest from the passive optical cavity of the ring resonator, the optical waveguide having an inner wall closest to the passive optical cavity of the ring resonator, the optical waveguide having a top surface and a bottom surface, the optical waveguide having a substantiall

Assignees

• Ayar Labs Inc

Inventors

• Fini john
• Van Orden Derek
• Wade Mark

Classifications

• G02B6/29338

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• G02B6/12007 Primary

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• G02B6/2934 Primary

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