Optical waveguide element, optical modulator, optical modulation module, and optical transmission device

Patent metadata

Field	Value
Publication number	US-11333909-B2
Application number	US-202017105615-A
Country	US
Kind code	B2
Filing date	Nov 26, 2020
Priority date	Dec 26, 2019
Publication date	May 17, 2022
Grant date	May 17, 2022

Abstract

An optical waveguide element is provided to effectively reduce an optical absorption loss of waveguide light which may occur at an intersecting part between an optical waveguide and an electrode without causing deterioration in optical characteristics and degradation of long-term reliability of the optical waveguide element. The optical waveguide element includes an optical waveguide formed in a substrate, and an electrode controlling optical waves propagated in the optical waveguide and having an intersecting part intersecting the optical waveguide thereabove. A portion of a resin layer is provided between the optical waveguide and the electrode in a portion of the substrate including the intersecting part. A corner of the resin layer on a side of the electrode is constituted to be a curve in a cross section in an extending direction of the electrode.

First claim

What is claimed is:

1. An optical waveguide element, comprising:
an optical waveguide formed in a substrate; and
an electrode controlling optical waves that are propagated in the optical waveguide and having an intersecting part intersecting the optical waveguide thereabove,
wherein a portion of a resin layer is provided between the optical waveguide and the electrode in a portion of the substrate including the intersecting part,
wherein an upper surface of the resin layer is in direct contact with a bottom surface of the electrode and a bottom surface of the resin layer opposite to the upper surface is in direct contact with a top surface of the optical waveguide, and
wherein the upper surface of the resin layer curves down toward the top surface of the optical waveguide at an edge of the upper surface of the resin layer to relief a stress created by a corner of the resin layer to the electrode above the resin layer.

2. The optical waveguide element according to claim 1 ,
wherein in the resin layer, a distance measured in the extending direction of the electrode from a starting point to an end part of the curve constituting the corner in the cross section is longer than a height of the resin layer measured from a surface of the substrate.

3. The optical waveguide element according to claim 1 ,
wherein the resin layer is provided over a distance equal to or longer than three times a width of the optical waveguide at the intersecting part in the extending direction of the electrode.

4. The optical waveguide element according to claim 1 ,
wherein at the intersecting part, a plurality of the resin layers is provided between the optical waveguide and the electrode in a manner of being stacked in a stepped shape in the extending direction of the electrode.

5. The optical waveguide element according to claim 1 ,
wherein at the intersecting part, an insulating layer comprising SiO 2 is formed between the optical waveguide and the resin layer.

6. The optical waveguide element according to claim 1 ,
wherein a resin constituting the resin layer is a resin formed using a photoresist including a crosslinking agent.

7. The optical waveguide element according to claim 1 ,
wherein the resin layer is formed in a manner of straddling the adjacent intersecting part.

8. The optical waveguide element according to claim 1 ,
wherein the electrode is formed to be thicker than 10 μm at least at the intersecting part.

9. The optical waveguide element according to claim 1 ,
wherein the substrate has a thickness equal to or smaller than 20 μm.

10. An optical modulator comprising:
the optical waveguide element according to claim 1 serving as an optical modulation element performing a modulation of light;
a casing for accommodating the optical waveguide element;
an optical fiber for inputting light to the optical waveguide element; and
an optical fiber for guiding light output by the optical waveguide element to an outside of the casing.

11. An optical modulation module comprising:
the optical waveguide element according to claim 1 serving as an optical modulation element performing a modulation of light; and
a drive circuit for driving the optical waveguide element.

12. An optical transmission device comprising:
the optical modulator according to claim 10 ; and
an electronic circuit that generates an electrical signal to cause the optical waveguide element to perform a modulation operation.

13. An optical transmission device comprising:
the optical modulation module according to claim 11 ; and
an electronic circuit that generates an electrical signal to cause the optical waveguide element to perform a modulation operation.

Assignees

• Sumitomo Osaka Cement Co Ltd

Inventors

• Okahashi Kousuke
• Sugamata Toru

Classifications

• G02F1/011 Primary

  in optical waveguides, not otherwise provided for in this subclass · CPC title

• G02F1/0316

  Electrodes · CPC title

• G02F1/0356 Primary

  controlled by a high-frequency electromagnetic wave component in an electric waveguide structure · CPC title

• G02F1/225

  in an optical waveguide structure · CPC title

• G02F2201/07

  buffer layer · CPC title