# US 8,542,434 B2 · Optical waveguide devices and harmonic wave generating devices

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- Number: US 8,542,434 B2
- Document ID: US8542434B2
- Status: Granted
- Kind: B2
- Application number: 13/220,015
- Filed: 2011-08-29
- Published: 2012-03-01
- Granted: 2013-09-24
- Earliest claimed: 2010-09-01
- Assignees: NGK Insulators, Ltd.
- Applicants: Jungo Kondo; Tetsuya Ejiri; Yuichi Iwata; Shoichiro Yamaguchi; Taku Nishigaki
- Inventors: Jungo Kondo; Tetsuya Ejiri; Yuichi Iwata; Shoichiro Yamaguchi; Taku Nishigaki
- Web page: https://patentgrep.com/patent/US8542434B2

## CPC

- G02F 1/3775: {with a periodic structure, e.g. domain inversion, for quasi-phase-matching [QPM] (G02F1/383 takes precedence)}
- 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

An optical waveguide device includes a ferroelectric layer having a thickness of 4 μm-7 μm; a supporting body; and an adhesive layer adhering a bottom face of the ferroelectric layer and supporting body. The ferroelectric layer includes a ridge comprising a channel optical waveguide, first and second protuberances on opposite sides of the ridge, inner grooves between the ridge and protuberances, respectively, and outer grooves outside of the protuberances, respectively. The outer groove is deeper than the inner groove. The ridge portion has a width of 6.6 μm-8.5 μm, a distance of an outer edge of the first protuberance and an outer edge of the second protuberance is 8.6 μm-20 μm, the inner groove has a depth of 2.0 μm-2.9 μm, and the outer groove has a depth of 2.5 μm-3.5 μm.

## Claims

### Claim 1

An optical waveguide device comprising:
a ferroelectric layer comprising a ferroelectric material and having a thickness of 4 μm or more and 7 μm or less; a supporting body; and an adhesive layer adhering a bottom face of said ferroelectric layer and said supporting body, wherein said ferroelectric layer comprises a ridge portion comprising a channel type optical waveguide formed therein, a first protuberance provided on a first side of said ridge portion, and a second protuberance provided on a second side of said ridge portion, wherein inner grooves are formed between said ridge portion and said protuberances, respectively; wherein outer grooves are formed outside of said protuberances, respectively; wherein said outer grooves are deeper than said inner grooves; wherein said ridge portion has a width W1 of 6.6 μm or larger and 8.5 μm or smaller; wherein a distance W2 of an outer edge of said first protuberance and an outer edge of said second protuberance is 8.6 μm or larger and 20 μm or smaller;
wherein said inner grooves have a depth D1 of 2.0 μm or larger and 2.9 μm or smaller; and wherein said outer grooves have a depth D2 of 2.5 μm or larger and 3.5 μm or smaller.

### Claim 2 (depends on 1)

The optical waveguide device of claim 1, wherein said adhesive layer comprises an inorganic adhesive contacting said ferroelectric layer.

### Claim 3 (depends on 1)

The optical waveguide device of claim 1, wherein said ferroelectric material comprises lithium niobate, lithium tantalate, lithium niobate-lithium tantalate solid solution, K3Li2Nb5O15 or La3Ga5SiO14.

### Claim 4 (depends on 1)

The optical waveguide device of claim 1, wherein said inner grooves and said outer grooves are formed by laser ablation.

### Claim 5 (depends on 1)

A harmonic wave generating device, comprising said optical waveguide device of claim 1 and a periodic domain inversion structure formed in said ridge portion.

### Claim 6

An optical waveguide device comprising:
a ferroelectric layer comprising a ferroelectric material and having a thickness of 4 μm or more and 7 μm or less;
a supporting body; and
an adhesive layer adhering a bottom face of said ferroelectric layer and said supporting body,
wherein said ferroelectric layer comprises a ridge portion comprising a channel type optical waveguide formed therein, a first step portion provided on a first side of said ridge portion and having a height smaller than that of said ridge portion, and a second step portion provided on a second side of said ridge portion and having a height smaller than that of said ridge portion,
wherein grooves are formed in outside of said step portions, respectively;
wherein said ridge portion has a width W1 of 6.6 μm or larger and 8.5 μm or smaller;
wherein a distance W2 of an outer edge of said first step portion and an outer edge of said second step portion is 8.6 μm or larger and 20 μm or smaller;
wherein said step portion has a depth D5 of 2.0 μm or larger and 2.9 μm or smaller; and
wherein said groove has a depth D4 of 2.5 μm or larger and 3.5 μm or smaller.

### Claim 7 (depends on 6)

The optical waveguide device of claim 6, wherein said adhesive layer comprises an inorganic adhesive contacting said ferroelectric layer.

### Claim 8 (depends on 6)

The optical waveguide device of claim 6, wherein said ferroelectric material comprises lithium niobate, lithium tantalate, lithium niobate-lithium tantalate solid solution, K3Li2Nb5O15 or La3Ga5SiO14.

### Claim 9 (depends on 6)

The optical waveguide device of claim 6, wherein said grooves and said step portions are formed by laser ablation.

### Claim 10 (depends on 6)

A harmonic wave generating device, comprising said optical waveguide device of claim 6 and a periodic domain inversion structure formed in said ridge portion.