Method of fabricating wavelength conversion device

Patent metadata

Field	Value
Publication number	US-9405168-B2
Application number	US-201414512627-A
Country	US
Kind code	B2
Filing date	Oct 13, 2014
Priority date	Oct 18, 2013
Publication date	Aug 2, 2016
Grant date	Aug 2, 2016

Abstract

Disclosed is a method for fabricating a wavelength conversion device that is capable of suppressing unintended and random polarization reversal due to heating thereby achieving higher wavelength conversion efficiency. The method includes: forming an insulating layer on one place of a crystal substrate naturally and uniformly polarized in a thickness direction; forming an insulating layer pattern with line-and-space by photolithography; then supplying conductive fluid to both planes of the crystal substrate to apply voltage to the crystal substrate, thereby a wavelength conversion device that is periodically polarization-reversed is fabricated. When temperature of the crystal substrate decreases after heating, an ionizer supplies ions to a surface of the crystal substrate, negative ions collect on +z plane, and positive ion collect on −z plane, thereby unintended and random polarization reversal is suppressed.

First claim

What is claimed is:

1. A method of fabricating a wavelength conversion device, the device being fabricated from a crystal substrate and having a structure that is periodically polarization-reversed in the direction perpendicular to a thickness direction of the crystal substrate formed from a ferroelectric crystal demonstrating a non-linear optical effect, the method comprising:
heating the crystal substrate; and
removing electricity on a surface of the crystal substrate when temperature of the crystal substrate being changing due to the heating, the method further comprising:
forming an insulating layer on at least one plane of the crystal substrate;
forming a pattern with line-and-space of the insulating layer; and
periodically applying voltage to the crystal substrate using the formed pattern with line-and-space of the insulating layer, wherein
the heating is carried out after the forming the insulating layer, and before or after the forming the pattern.

2. The method of fabricating a wavelength conversion device according to claim 1
wherein
the removing electricity is carried out by collecting, on the surface of the crystal substrate, ions having a polarity different from a polarity on a region of the surface of the crystal substrate in which natural polarization occurs.

3. The method of fabricating a wavelength conversion device according to claim 2
wherein
the removing electricity is carried out by use of an ionizer.

4. The method of fabricating a wavelength conversion device according to claim 3 , the applying voltage further comprising:
supplying conductive fluid to the crystal substrate in a manner that the conductive fluid contacts a region of the surface of the crystal substrate that is not covered with the insulating layer, the region consisting of each of linear portions constituting the line-and-space; and
applying the voltage to the crystal substrate through the conductive fluid.

5. The method of fabricating a wavelength conversion device according to claim 3 , wherein
the heating is carried out after forming the insulating layer.

6. The method of fabricating a wavelength conversion device according to claim 3 , wherein
the removing electricity is carried out when the temperature of the crystal substrate decreases.

7. A wavelength conversion device fabricated by the method of fabricating a wavelength conversion device according to claim 3 .

8. The method of fabricating a wavelength conversion device according to claim 2 , the applying voltage further comprising:
supplying conductive fluid to the crystal substrate in a manner that the conductive fluid contacts a region of the surface of the crystal substrate that is not covered with the insulating layer, the region consisting of each of linear portions constituting the line-and-space; and
applying the voltage to the crystal substrate through the conductive fluid.

9. The method of fabricating a wavelength conversion device according to claim 2 , wherein
the heating is carried out after forming the insulating layer.

10. The method of fabricating a wavelength conversion device according to claim 2 , wherein
the removing electricity is carried out when the temperature of the crystal substrate decreases.

11. A wavelength conversion device fabricated by the method of fabricating a wavelength conversion device according to claim 2 .

12. The method of fabricating a wavelength conversion device according to claim 1 , the applying voltage further comprising:
supplying conductive fluid to the crystal substrate in a manner that the conductive fluid contacts a region of the surface of the crystal substrate that is not covered with the insulating layer, the region consisting of each of linear portions constituting the line-and-space; and
applying the voltage to the crystal substrate through the conductive fluid.

13. The method of fabricating a wavelength conversion device according to claim 12 , wherein
the removing electricity is carried out when the temperature of the crystal substrate decreases.

14. A wavelength conversion device fabricated by the method of fabricating a wavelength conversion device according to claim 12 .

15. The method of fabricating a wavelength conversion device according to claim 1 , wherein
the heating is carried out after forming the insulating layer.

16. The method of fabricating a wavelength conversion device according to claim 1 , wherein
the removing electricity is carried out when the temperature of the crystal substrate decreases.

17. A wavelength conversion device fabricated by the method of fabricating a wavelength conversion device according to claim 1 .

Assignees

• Ushio Electric Inc

Inventors

• Ota Keisuke

Classifications

• G02F1/37

  for second-harmonic generation {(G02F1/3532 takes precedence)} · CPC title

• C30B29/30

  Niobates; Vanadates; Tantalates · CPC title

• G02F1/3551

  Crystals · CPC title

• G02F1/3544 Primary

  Particular phase matching techniques · CPC title

• G02F1/3558 Primary

  Poled materials, e.g. with periodic poling; Fabrication of domain inverted structures, e.g. for quasi-phase-matching [QPM] · CPC title