# US 2025/0093577 A1 · Vertical grating coupler

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2025/0093577 A1
- Document ID: US20250093577A1
- Status: Published application
- Kind: A1
- Application number: 18/969,375
- Filed: 2024-12-05
- Published: 2025-03-20
- Earliest claimed: 2022-05-24
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Taiwan Semiconductor Manufacturing Company, LTD.
- Inventors: Tai-Chun Huang; Stefan Rusu
- Web page: https://patentgrep.com/patent/US20250093577A1

## CPC

- G02B 6/12002: {Three-dimensional structures}
- G02B 6/124: Geodesic lenses or integrated gratings
- G02B 6/34: utilising prism or grating {(G02B6/293 takes precedence)}
- G02B 1/002: {made of materials engineered to provide properties not available in nature, e.g. metamaterials}
- G02B 6/4215: {the intermediate optical elements being wavelength selective optical elements, e.g. variable wavelength optical modules or wavelength lockers (G02B6/4246 takes precedence)}
- G02B 2006/12107: {Grating}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

A vertical grating coupler is disclosed. The grating coupler includes a first waveguide having a first grating, a second waveguide having a second grating, and a dielectric layer positioned between the first waveguide and the second waveguide. The first grating includes a plurality of first grating ridges separated by a plurality first grating gaps, and the second grating includes a plurality of second grating ridges separated by a plurality second grating gaps. The first grating, the second grating, and the dielectric layer are located in a vertical overlap region between the first waveguide and the second waveguide. The first grating and the second grating have different grating periods, and each of the plurality of first grating gaps and second grating gaps are filled with the dielectric layer.

## Claims

### Claim 1

A method for fabricating a vertical grating coupler, comprising:
forming a first waveguide in a first optical routing layer on a substrate;
forming a first grating in the first waveguide, the first grating comprising a plurality of first grating ridges having a first grating period;
forming an overlay on the plurality of first grating ridges;
forming a dielectric layer above the first waveguide from a first dielectric material;
etching a plurality of grooves in the dielectric layer; and
forming a second waveguide on the dielectric layer in a second optical routing layer on the substrate, wherein a second grating comprising a plurality of second grating ridges in the plurality of grooves having a second grating period is formed therein,
wherein the first waveguide, the first grating, the second grating, and the second waveguide overlap in a vertical overlap region.

### Claim 2 (depends on 1)

The method of claim 1, wherein dielectric layer has a thickness of about 1 nanometer to 1100 nanometers.

### Claim 3 (depends on 1)

The method of claim 1, wherein the first waveguide and the second waveguide are comprised of silicon nitride or silicon.

### Claim 4 (depends on 1)

The method of claim 1, wherein the overlay has a thickness of about 10% to about 50% of the ridge.

### Claim 5 (depends on 1)

The method of claim 1, wherein the first grating and the second grating are apodized.

### Claim 6 (depends on 1)

The method of claim 1, wherein the first grating period of the first grating is about 100 nanometers to about 500 nanometers.

### Claim 7 (depends on 1)

The method of claim 1, wherein the second grating period of the second grating is about 100 nanometers to about 500 nanometers.

### Claim 8 (depends on 1)

The method of claim 1, wherein the first grating has a width of about 5% to about 99% of a width of an output width of the first waveguide.

### Claim 9 (depends on 1)

The method of claim 1, wherein the second grating has a width of about 5% to about 99% of a width of an input of the second waveguide.

### Claim 10 (depends on 1)

The method of claim 1, wherein the first waveguide and the second waveguide each have a thickness of about 10 nanometers to about 1200 nanometers.

### Claim 11 (depends on 1)

The method of claim 1, wherein the first waveguide and the second waveguide each have a width of about 200 nanometers to about 2000 nanometers.

### Claim 12 (depends on 1)

The method of claim 1, wherein the dielectric layer comprises a high-K material.

### Claim 13

A vertical grating coupler, comprising:
a first waveguide having a first grating formed therein, the first grating including a plurality of first grating ridges separated by a plurality first grating gaps;
a second waveguide having a second grating formed therein, the second grating including a plurality of second grating ridges separated by a plurality second grating gaps; and
a dielectric layer positioned between the first waveguide and the second waveguide, wherein the first grating, the second grating, and the dielectric layer are located in a vertical overlap region, each of the first grating and the second grating having a different grating period;
wherein each of the plurality of first grating gaps and second grating gaps are filled with the dielectric layer; and
wherein the first waveguide and the second waveguide each have a width of about 200 nanometers to about 2000 nanometers.

### Claim 14 (depends on 13)

The device of claim 13, wherein the first waveguide and the second waveguide comprise silicon nitride.

### Claim 15 (depends on 13)

The device of claim 13, wherein the dielectric layer has a thickness of about 1 nanometer to 1100 nanometers.

### Claim 16 (depends on 13)

The device of claim 13, wherein the first grating has a width of about 5% to about 99% of a width of an output width of the first waveguide, and wherein the second grating has a width of about 5% to about 99% of a width of an input of the second waveguide.

### Claim 17 (depends on 13)

The device of claim 13, wherein the first grating and the second grating are apodized.

### Claim 18

A method for using a vertical grating coupler, comprising:
sending an optical input into a first waveguide, the optical input comprising a plurality of different wavelengths;
transiting the optical input from the first waveguide through a first grating disposed on the first waveguide into a dielectric layer, wherein the dielectric layer has a thickness of about 1 nanometer to 1100 nanometers;
transiting the optical input from the dielectric layer into a second waveguide through a second grating disposed on the second waveguide, the first grating and the second grating positioned opposite each other with the dielectric layer located therebetween; and
sending the optical input through the second waveguide to an optical output.

### Claim 19 (depends on 18)

The method of claim 18, wherein the first grating and the second grating have different grating periods.

### Claim 20 (depends on 18)

The method of claim 18, wherein the first waveguide and the second waveguide each have a width of about 200 nanometers to about 2000 nanometers.