# US 12,222,590 B2 · Lithium niobate waveguide having weak phase drift

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- Number: US 12,222,590 B2
- Document ID: US12222590B2
- Status: Granted
- Kind: B2
- Application number: 17/638,819
- Filed: 2021-05-14
- Published: 2022-09-29
- Granted: 2025-02-11
- Earliest claimed: 2020-05-14
- Applicants: SHANGHAI LYCORE TECHNOLOGIES Co., Ltd.
- Inventors: Hanxiao Liang; Yipin Song; Yingcong Zhou; Haicang Wu; Wenhao Mao; Shiwei Song; Weiqi Sun; Qingyang Yu
- Web page: https://patentgrep.com/patent/US12222590B2

## CPC

- G02F 1/0305: {Constructional arrangements (G02F1/0327 - G02F1/05 take precedence)}
- G02F 1/035: in an optical waveguide structure
- G02F 1/0316: {Electrodes}
- G02F 1/365: in an optical waveguide structure (G02F1/377, {G02F1/395} take precedence)
- G02F 2201/063: ridge; rib; strip loaded
- G02F 2202/20: LiNbO3, LiTaO3
- 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

A lithium niobate waveguide having weak phase drift includes a lithium niobate layer, a metal electrode, and a substrate layer. The lithium niobate layer includes a lithium niobate central ridge and lithium niobate extension surfaces extending towards two sides of the lithium niobate central ridge. A metal oxide layer is arranged on the upper surface of the lithium niobate central ridge. The substrate layer is located on the lower surface of the lithium niobate layer and is made of silicon, silicon dioxide, a multilayer material made of silicon and silicon dioxide or a multilayer material made of silicon dioxide, metal, and silicon, so as to further realize the purpose of inhibiting phase drift. Compared with other doped structures or other structures, the structure is simple in manufacturing method, and moreover, a very good phase drift suppression effect is achieved.

## Claims

### Claim 1

A lithium niobate waveguide having weak phase drift, comprising:
a lithium niobate layer,
a metal electrode, and
a substrate layer,
wherein the lithium niobate layer comprises a lithium niobate central ridge and lithium niobate extension surfaces extending towards two sides of the lithium niobate central ridge,
wherein a metal oxide layer is disposed on an upper surface of the lithium niobate central ridge, and
wherein the substrate layer is located on a lower surface of the lithium niobate layer,
wherein a thickness of the lithium niobate central ridge ranges from 0.2 to 3 μm, a thickness of each lithium niobate extension surface ranges from 0.1 to 1 μm, and a width of the lithium niobate central ridge ranges from 0.3 to 3 μm,
wherein the metal oxide layer is disposed on upper surfaces of the lithium niobate extension surfaces and a side surface of the central ridge,
wherein the metal electrode passes through partial or all of the metal oxide layers, and/or partial or all of the lithium niobate extension surfaces, and/or partial or all of the lower substrate layer to be connected to a surface of a lowermost layer that is passed through.

### Claim 2 (depends on 1)

The lithium niobate waveguide having weak phase drift as claimed in claim 1, wherein the substrate layer is comprised of silicon, silicon dioxide, a multilayer material made of silicon and silicon dioxide or a multilayer material made of silicon dioxide, metal, and silicon.

### Claim 3 (depends on 1)

The lithium niobate waveguide having weak phase drift as claimed in claim 1, wherein the metal electrode is connected to the upper surfaces of the metal oxide layers.

### Claim 4 (depends on 1)

The lithium niobate waveguide having weak phase drift as claimed in claim 1, wherein the metal electrode is connected to the upper surfaces of the lithium niobate extension surfaces.

### Claim 5 (depends on 1)

The lithium niobate waveguide having weak phase drift as claimed in claim 1, wherein the metal electrode passes through partial or all of the lithium niobate extension surfaces, and/or partial or all of the lower substrate layer to be connected to a surface of a lowermost layer that is passed through.

### Claim 6 (depends on 1)

The lithium niobate waveguide having weak phase drift as claimed in claim 1, wherein the maximum thickness of the metal oxide layers is less than 2 μm.

### Claim 7 (depends on 1)

The lithium niobate waveguide having weak phase drift as claimed in claim 1, wherein the metal oxide layers is comprised of aluminum oxide, hafnium oxide, tantalum oxide, zirconium dioxide or titanium dioxide.