Unlock instant, AI-driven research and patent intelligence for your innovation.

Optical waveguide device

a technology of optical waveguides and applied in the direction of optical waveguide light guides, instruments, optics, etc., can solve the problems of deteriorating transmission characteristics and easy to see problems, and achieve the effect of suppressing deterioration of transmission characteristics

Inactive Publication Date: 2020-01-30
SUMITOMO OSAKA CEMENT CO LTD
View PDF16 Cites 4 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention aims to address the problem of deteriorated optical waveguide device performance caused by heat shrinkage of objects placed on a substrate. By placing the object on the substrate in a way that they cover a part or all of the mode conversion / branching portion, the invention aims to suppress the heat-related issues that affect the device's performance.

Problems solved by technology

As a result, deterioration in an On / Off extinction ratio in each Mach-Zehnder type waveguide or a loss difference between branched waveguide sections (Mach-Zehnder type waveguide arm sections) occurs, and thus there is a problem in that transmission characteristics deteriorate.
The problem becomes more easily apparent in a case of a multilayer structure in which substrates of different kinds of materials with greatly different linear expansion coefficients or Young's moduli are stuck to each other, particularly, a structure in which an LN thin plate is reinforced with a reinforcing substrate.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Optical waveguide device
  • Optical waveguide device
  • Optical waveguide device

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0038]As illustrated in FIG. 2, the optical waveguide device related to Example 1 employs a considerably thin substrate (that is, a thin plate) as a substrate 10, and has a multilayer structure to be reinforced by adhering a reinforcing substrate 12 thereto via an adhesive 11. The substrate 10 is made of a material such as lithium niobate (LN) having an excellent piezoelectric effect. A thickness of the substrate 10 is about 20 μm, a thickness of the adhesive 11 is about 20 μm to 100 μm, and a thickness of the reinforcing substrate 12 is about 400 μm to 1000 μm.

[0039]An optical waveguide 20 formed on the substrate 10 includes mode conversion / branching portions 23 and 24 that convert a mode of a light wave propagating through the optical waveguide and branch the light wave. The mode conversion / branching portion 23 is a mode conversion / branching portion located on the most upstream side in a light wave advancing direction, and the mode conversion / branching portion 24 is the second mod...

example 2

[0044]In Example 2, as illustrated in a sectional view of a lower part of FIG. 3, the reinforcing member 31 is disposed to cover the whole mode conversion / branching portion 23. The control electrode 32 is disposed to cover the whole mode conversion / branching portion 24.

[0045]According to the structure, a refractive index distribution due to stress caused by heat shrinkage of objects on the substrate 10 also hardly occurs in the regions of the mode conversion / branching portions 23 and 24. As a result, since a branch ratio of propagating light of when a light wave is branched is stabilized, it is possible to suppress deterioration in transmission characteristics.

[0046]Disposing an object to cover the whole mode conversion / branching portion does not indicate that the object is present in the entire region of the substrate in the width direction of the substrate. In other words, even though a position of the substrate in the longitudinal direction of the substrate is a region overlappin...

example 3 and example 4

[0047]Example 3 illustrated in FIG. 4 is a modification example of Example 1 illustrated in FIG. 2. Example 4 illustrated in FIG. 5 is a modification example of Example 2 illustrated in FIG. 3. The optical waveguide devices of Example 1 and Example 2 have a multilayer structure, and are reinforced by adhering the reinforcing substrate 12 to a back surface of the substrate 10 formed to be considerably thin, but optical waveguide devices of Example 3 and Example 4 have a single-layer structure, and the substrate 10 is formed to be thick to the extent to which sufficient strength is obtained.

[0048]Even in a case where the optical waveguide device has a single-layer structure, a refractive index distribution may occur due to stress caused by heat shrinkage of an object on the substrate 10. Therefore, as illustrated in FIGS. 4 and 5, a branch ratio of propagating light of when a light wave is branched is stabilized through examination of disposition of an object on the substrate 10, and ...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

An optical waveguide device includes a substrate on which an optical waveguide is formed, and an object that is disposed on the substrate. The optical waveguide includes a mode conversion / branching portion that converts a mode of a light wave propagating through the optical waveguide and branches the light wave, and the object is disposed to cover a part or the whole of the mode conversion / branching portion or not to cover the mode conversion / branching portion when the substrate is viewed in a plan view. In a case where the object is disposed to cover a part of the mode conversion / branching portion, the object is disposed not to consecutively cover a section over a length of a predetermined value or higher in an advancing direction of a light wave.

Description

BACKGROUND OF THE INVENTIONField of the Invention[0001]The present invention relates to a substrate provided with an optical waveguide and an optical waveguide device having an object disposed on the substrate.Description of Related Art[0002]In an optical communication field, an optical modulator that performs optical modulation corresponding to transmission data on an input light wave, and outputs the light wave. FIG. 1 illustrates a structure of an optical waveguide device built into an optical modulator of the related art. An upper part of FIG. 1 is a plan view of a part of the optical waveguide device (a portion corresponding to a light wave input side), and a lower part thereof is a sectional view of the part.[0003]The optical waveguide device is configured by forming an optical waveguide 20 including a Mach-Zehnder type waveguide used to perform optical modulation on a front surface side of a substrate 10 having an electro-optic effect. The optical waveguide 20 may be a nest t...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
IPC IPC(8): G02F1/225G02F1/00G02F1/313
CPCG02F1/225G02F1/0018G02F1/3137G02F2201/18G02F2201/06G02F2202/10G02F2001/212G02B6/10G02B6/14G02F1/212
Inventor KATOU, KEIMIYAZAKI, NORIKAZU
Owner SUMITOMO OSAKA CEMENT CO LTD