# US 2025/0147232 A1 · Photonic chip with an optical resonator coupler

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- Number: US 2025/0147232 A1
- Document ID: US20250147232A1
- Status: Published application
- Kind: A1
- Application number: 18/939,047
- Filed: 2024-11-06
- Published: 2025-05-08
- Earliest claimed: 2023-11-07
- Applicants: Imec Vzw
- Inventors: Christian Haffner; Kristiaan De Greve; Junwen He
- Web page: https://patentgrep.com/patent/US20250147232A1

## CPC

- G02B 6/12004: {Combinations of two or more optical elements}
- G02B 6/12007: {forming wavelength selective elements, e.g. multiplexer, demultiplexer}
- G02B 6/1228: {Tapered waveguides, e.g. integrated spot-size transformers (for coupling with fibres G02B6/305)}
- G02B 6/136: by etching
- G02B 6/29341: {Loop resonators operating in a whispering gallery mode evanescently coupled to a light guide, e.g. sphere or disk or cylinder (evanescent coupling for sensing fluorescence G01N21/648)}
- H04B 10/801: {using optical interconnects, e.g. light coupled isolators, circuit board interconnections}
- G02B 6/29343: {Cascade of loop resonators}
- G02B 6/30: for use between fibre and thin-film device
- G02B 2006/12035: {Materials}
- G02B 2006/12104: {Mirror; Reflectors or the like}
- G02B 2006/12147: {Coupler}
- G02F 2203/15: involving resonance effects, e.g. resonantly enhanced interaction
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- H04B: TRANSMISSION
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS

## Abstract

The present disclosure relates to a photonic chip comprising a first optical propagation element and an optical resonator for optically coupling the first optical propagation element to a second optical propagation element. The second optical propagation element may be external the photonic chip or a part of the photonic chip. The first optical propagation element comprises a first material with a first refractive index that is higher than a second refractive index of a second material of the second optical propagation element. An optical coupling efficiency of above 99% can be achieved.

## Claims

### Claim 1

A photonic chip comprising:
a first optical propagation element; and
an optical resonator for optically coupling the first optical propagation element to a second optical propagation element;
wherein the first optical propagation element comprises a first material with a first refractive index that is higher than a second refractive index of a second material of the second optical propagation element.

### Claim 2 (depends on 1)

The photonic chip of claim 1, wherein the second optical propagation element is external to the photonic chip, and the optical resonator is part of an optical coupler of the photonic chip configured to optically couple the photonic chip to the external second optical propagation element.

### Claim 3 (depends on 2)

The photonic chip of claim 2, wherein the second optical propagation element is an optical fiber and/or wherein the first optical propagation element is a silicon waveguide or a silicon nitride waveguide or an alumina waveguide.

### Claim 4 (depends on 3)

The photonic chip of claim 3, wherein the second refractive index of the optical fiber is in a range of 1-2.

### Claim 5 (depends on 1)

The photonic chip of claim 1, wherein the photonic chip comprises the second optical propagation element and/or wherein the first optical propagation element comprises a silicon waveguide and the second optical propagation element comprises a silicon nitride waveguide.

### Claim 6 (depends on 5)

The photonic chip of claim 5, wherein the optical resonator is made of silicon, silicon nitride, or alumina, and/or wherein the optical resonator is integrated with the first optical propagation element or the second optical propagation element.

### Claim 7 (depends on 6)

The photonic chip of claim 6, wherein the optical resonator is a ring resonator, a Fabry-Perot resonator, or a 1D photonic crystal resonator.

### Claim 8 (depends on 7)

The photonic chip of the claim 7, wherein the optical resonator comprises a racetrack waveguide or comprises a waveguide with varying width.

### Claim 9 (depends on 8)

The photonic chip of the claim 8, wherein the optical resonator is arranged on or embedded in a substrate of the photonic chip.

### Claim 10 (depends on 9)

The photonic chip of claim 9, wherein the substrate is etched at least in the vicinity of the optical resonator.

### Claim 11 (depends on 10)

The photonic chip of claim 10, wherein a distance of the optical resonator to the second optical propagation element, when the first optical propagation element is coupled to the second optical propagation element, is determined by the structure of the etched substrate and/or is in a range of 200 nm to 10 μm.

### Claim 12 (depends on 10)

The photonic chip of claim 10, wherein a distance of the optical resonator to the second optical propagation element, when the first optical propagation element is coupled to the second optical propagation element, is determined by depth at which the optical resonator is embedded below a surface of the substrate.

### Claim 13 (depends on 1)

The photonic chip of claim 1, further comprising at least one phase shifting element configured to tune a resonance frequency of the optical resonator.

### Claim 14 (depends on 1)

The photonic chip of claim 1, further comprising a tunable coupler, wherein the tunable coupler comprises the first optical propagation element and a section of the optical resonator.

### Claim 15 (depends on 1)

The photonic chip of claim 1, wherein the photonic chip comprises a set of two or more detuned optical resonators including the optical resonator, wherein the set of optical resonators is configured to optically couple the first optical propagation element to the second optical propagation element.

### Claim 16 (depends on 1)

The photonic chip of claim 1, wherein the second optical propagation element is an optical fiber and/or wherein the first optical propagation element is a silicon waveguide or a silicon nitride waveguide or an alumina waveguide.

### Claim 17 (depends on 1)

The photonic chip of claim 1, wherein the optical resonator is made of silicon, silicon nitride, or alumina, and/or wherein the optical resonator is integrated with the first optical propagation element or the second optical propagation element.

### Claim 18 (depends on 1)

The photonic chip of claim 1, wherein the optical resonator is a ring resonator, a Fabry-Perot resonator, or a 1D photonic crystal resonator.

### Claim 19 (depends on 1)

The photonic chip of claim 1, wherein the optical resonator comprises a racetrack waveguide or comprises a waveguide with varying width.

### Claim 20 (depends on 1)

The photonic chip of claim 1, wherein the optical resonator is arranged on or embedded in a substrate of the photonic chip.