# US 2024/0201435 A1 · Compact optical resonator with enhancement features

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- Number: US 2024/0201435 A1
- Document ID: US20240201435A1
- Status: Published application
- Kind: A1
- Application number: 18/324,513
- Filed: 2023-05-26
- Published: 2024-06-20
- Earliest claimed: 2022-12-19
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Taiwan Semiconductor Manufacturing Company, Ltd.
- Inventors: Wen-Hao Cheng
- Web page: https://patentgrep.com/patent/US20240201435A1

## CPC

- G02B 6/12002: {Three-dimensional structures}
- G02B 6/1223: {high refractive index type, i.e. high-contrast waveguides}
- G02B 6/29335: {Evanescent coupling to a resonator cavity, i.e. between a waveguide mode and a resonant mode of the cavity (wavelength selective means based on resonator cavity coupled non-evanescently G02B6/29356, G02B6/29358)}
- G02B 6/29338: {Loop resonators}
- G02B 6/12007: {forming wavelength selective elements, e.g. multiplexer, demultiplexer}
- G02B 2006/1204: {Lithium niobate (LiNbO3)}
- G02B 2006/12061: {Silicon}
- G02B 2006/12078: {Gallium arsenide or alloys (GaAs, GaAlAs, GaAsP, GaInAs)}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

The present disclosure provides an embodiment of a photonics structure that includes a ring optical waveguide on a substrate; a rail optical waveguide configured to couple a light into the ring optical waveguide; and enhancement features configured around the ring optical waveguide and the rail optical waveguide to enhancement the photonic structure.

## Claims

### Claim 1

A photonics structure, comprising:
a ring optical waveguide on a substrate;
a rail optical waveguide configured to couple a light into the ring optical waveguide; and
enhancement features configured around the ring optical waveguide and the rail optical waveguide to enhancement the photonic structure.

### Claim 2 (depends on 1)

The photonics structure of claim 1, wherein the rail optical waveguide, the ring optical waveguide and the enhancement features are formed on a semiconductor substrate at a same level over the semiconductor substrate.

### Claim 3 (depends on 1)

The photonic structure of claim 1, wherein the rail optical waveguide, the ring optical waveguide and the enhancement features include a same material surrounded by a cladding material.

### Claim 4 (depends on 3)

The photonic structure of claim 3, wherein the cladding material includes silicon oxide.

### Claim 5 (depends on 1)

The photonic structure of claim 1, wherein the ring optical waveguide includes a nonlinear material selected from the group consisting of silicon nitride (SiN), lithium niobate (LiNbO3), aluminium gallium arsenide (AlGaAs), Indium phosphide (InP), aluminum nitride (AlN), and a combination thereof.

### Claim 6 (depends on 1)

The photonic structure of claim 1, wherein the enhancement features include
a first subset surrounded outside of the ring optical waveguide and extended on a first edge of the rail optical waveguide;
a second subset configured inside of the ring optical waveguide; and
a third subset configured on a second edge of the rail optical waveguide.

### Claim 7 (depends on 6)

The photonic structure of claim 6, wherein the enhancement features include a width less than a width of the rail optical waveguide and the ring optical waveguide.

### Claim 8 (depends on 6)

The photonic structure of claim 6, wherein
the ring optical waveguide and the rail optical waveguide include a first width ranging between 0.2λ and 2λ; and
the enhancement features include a second width ranging between 0.03λ and 0.09λ, wherein λ is the wavelength of the light.

### Claim 9 (depends on 6)

The photonic structure of claim 6, wherein each subset of the enhancement features includes a number N of the enhancement features, and wherein the number N ranges between 1 and 5.

### Claim 10 (depends on 1)

The photonic structure of claim 1, wherein
each subset of the enhancement features is arranged in a periodic configuration with a pitch P ranging between 0.06 and 0.122, a width W ranging between 0.4P and 0.7P, and a spacing S=P−W; and
λ is the wavelength of the light.

### Claim 11 (depends on 1)

The photonic structure of claim 1, wherein the enhancement features are free from a spacing between the ring optical waveguide and the rail optical waveguide.

### Claim 12 (depends on 1)

The photonic structure of claim 1, wherein the ring optical waveguide is a first ring optical waveguide, the rail optical waveguide is a first rail optical waveguide, the enhancement features are first enhancement features, and the light is a first light, the photonic structure further includes
a second ring optical waveguide;
a second rail optical waveguide configured to couple a second light into the second ring optical waveguide; and
second enhancement features configured around the second ring optical waveguide and the second optical rail optical waveguide to enhancement the photonic structure.

### Claim 13 (depends on 12)

The photonic structure of claim 12, wherein
the first ring optical waveguide, the first rail optical waveguide and the first enhancement features are positioned at a first level over the substrate; and
the second ring optical waveguide, the second rail optical waveguide and the second enhancement features are positioned at a second level over the substrate.

### Claim 14 (depends on 13)

The photonic structure of claim 13, wherein
the first and second levels are same; and
the first ring optical waveguide and the first rail optical waveguide are separated from the second ring optical waveguide and the second rail optical waveguide by the first and second enhancement features.

### Claim 15 (depends on 13)

The photonic structure of claim 13, wherein
the first and second levels are different; and
the first and second ring optical waveguides are vertically aligned over the substrate and are optically coupled.

### Claim 16 (depends on 15)

The photonic structure of claim 15, further comprising:
a third ring optical waveguide;
a third rail optical waveguide configured to couple a third light into the third ring optical waveguide; and
third enhancement features configured around the third ring optical waveguide and the third rail optical waveguide to enhancement the photonic structure, wherein
the third ring optical waveguide, the third rail optical waveguide, and the third enhancement features are positioned at a third lever over the substrate, and
the third level is different from the first and second levels.

### Claim 17

A photonics structure, comprising:
a first ring optical waveguide on a substrate;
a first rail optical waveguide configured to couple a first light into the first ring optical waveguide;
first enhancement features configured around the first ring optical waveguide and the first rail optical waveguide;
a second ring optical waveguide on the substrate;
a second rail optical waveguide configured to couple a second light into the second ring optical waveguide; and
second enhancement features configured around the second ring optical waveguide and the second rail optical waveguide, wherein
the first ring optical waveguide, the first rail optical waveguide and the first enhancement features are positioned at a first level over the substrate,
the second ring optical waveguide, the second rail optical waveguide and the second enhancement features are positioned at a second level over the substrate, and
the second level is different from the first level.

### Claim 18 (depends on 17)

The photonics structure of claim 17, wherein the first and second ring optical waveguides includes a nonlinear material selected from the group consisting of silicon nitride (SiN), lithium niobate (LiNbO3), aluminium gallium arsenide (AlGaAs), Indium phosphide (InP), aluminum nitride (AlN), and a combination thereof.

### Claim 19 (depends on 17)

The photonic structure of claim 17, wherein
the first enhancement features include a first subset surrounded outside of the first ring optical waveguide and extended on a first edge of the first rail optical waveguide, a second subset configured inside of the first ring optical waveguide, and a third subset configured on a second edge of the first rail optical waveguide; and
the second enhancement features include a fourth subset surrounded outside of the second ring optical waveguide and extended on a first edge of the second rail optical waveguide, a fifth subset configured inside of the second ring optical waveguide, and a sixth subset configured on a second edge of the second rail optical waveguide.

### Claim 20

A photonics structure, comprising:
a first optical ring resonator on a substrate at a first level, wherein the first optical ring resonator further includes a first ring optical waveguide, a first rail optical waveguide configured to couple a first light into the first ring optical waveguide, and first enhancement features configured around the first ring optical waveguide and the first rail optical waveguide;
a second optical ring resonator on the substrate at a second level, wherein the second optical ring resonator further includes a second ring optical waveguide, a second rail optical waveguide configured to couple a second light into the second ring optical waveguide, and second enhancement features configured around the second ring optical waveguide and the second rail optical waveguide; and
a third optical ring resonator on the substrate at a third level, wherein the third optical ring resonator further includes a third ring optical waveguide, a third rail optical waveguide configured to couple a third light into the third ring optical waveguide, and third enhancement features configured around the third ring optical waveguide and the third rail optical waveguide, wherein
the first, second and third levels are different from each other,
the first, second and third ring optical waveguides are vertically aligned, and
the first, second and third enhancement features have a width less than that of the first, second, and third ring optical waveguides.