Wavelength Conversion Element and Method for Producing Same

Patent metadata

Field	Value
Publication number	US-2022011647-A1
Application number	US-201917283466-A
Country	US
Kind code	A1
Filing date	Oct 8, 2019
Priority date	Oct 15, 2018
Publication date	Jan 13, 2022
Grant date	—

Abstract

A wavelength conversion element manufacturing method capable of realizing, in a wavelength conversion element having a structure in which a thin film substrate having a periodic polarization inversion structure and a support substrate are laminated, highly efficient wavelength conversion by confining light in a cross-sectional area smaller than in the known art. The manufacturing method includes steps of forming a periodic polarization inversion structure on a first substrate made of a second-order nonlinear optical crystal and forming a damage layer in the first substrate by implanting ions from one substrate surface to obtain a first substrate for bonding, directly bonding a second substrate having a bonding surface having a smaller refractive index than the first substrate to the one substrate surface of the first substrate at the bonding surface, and peeling the first substrate directly bonded to the second substrate being the support substrate with the damage layer as a boundary to remove a part of the first substrate.

First claim

1 . A wavelength conversion element, comprising:
an ultrathin thin film substrate having a periodic polarization inversion structure; and a support substrate being directly bonded to the thin film substrate and having a refractive index at a surface directly bonded to the thin film substrate that is smaller than a refractive index of the thin film substrate.

2 . The wavelength conversion element according to claim 1 , wherein the ultrathin thin film substrate includes a plurality of laminated layers.

3 . A method of manufacturing a wavelength conversion element, comprising:
a bonding substrate formation step of forming a periodic polarization inversion structure on a first substrate made of a second-order nonlinear optical crystal and forming a damage layer in the first substrate by implanting ions from one substrate surface to obtain a first substrate for bonding; a bonding step of directly bonding a second substrate having a bonding surface having a smaller refractive index than a refractive index of the first substrate to the one substrate surface of the first substrate at the bonding surface; and a substrate peeling step of peeling the first substrate directly bonded to the second substrate being a support substrate with the damage layer as a boundary to remove a part of the first substrate to obtain a wavelength conversion element in which an ultrathin thin film substrate is directly bonded onto the support substrate.

4 . The method of manufacturing a wavelength conversion element according to claim 3 , wherein, in the bonding substrate formation step, the damage layer is formed after the periodic polarization inversion structure is formed.

5 . The method of manufacturing a wavelength conversion element according to claim 3 , wherein, in the bonding substrate formation step, the periodic polarization inversion structure is formed after the damage layer is formed.

6 . The method of manufacturing a wavelength conversion element according to claim 3 , further comprising at least one of a substrate surface treatment step of polishing a surface of the ultrathin thin film substrate after the substrate peeling step to smooth the ultrathin thin film substrate, and a crystal defect compensation step of implanting atoms for compensating for a crystal defect into the ultrathin thin film substrate after the substrate peeling step.

7 . The method of manufacturing a wavelength conversion element according to claim 3 , wherein the first substrate is a substrate cut so that only an axis having a different refractive index runs along a direction perpendicular to a substrate surface.

8 . The method of manufacturing a wavelength conversion element according to claim 3 , further comprising: a bonding substrate reformation step of polishing a surface of the part of the first substrate removed by the peeling in the substrate peeling step, and forming a damage layer in a substrate of the part of the first substrate by implanting ions from one substrate surface to obtain a third substrate for bonding; and a thin film substrate laminating step of further performing the bonding step and the substrate peeling step by using the third substrate instead of the first substrate after the bonding substrate reformation step.

9 . The method of manufacturing a wavelength conversion element according to claim 3 , wherein, in the bonding substrate formation step, the periodic polarization inversion structure is formed only in a part of the first substrate.

10 . The method of manufacturing a wavelength conversion element according to claim 3 , wherein the first substrate contains LiNbO 3 , KNbO 3 , LiTaO 3 , LiNb(x)Ta(1−x)O 3 (0≤x≤1), or KTiOPO 4 , or at least one selected from the group consisting of Mg, Zn, Sc, and In as an additive in addition to LiNbO 3 , KNbO 3 , LiTaO 3 , LiNb(x)Ta(1-x)O 3 (0≤x≤1), or KTiOPO 4 .

11 . The method of manufacturing a wavelength conversion element according to claim 3 , wherein, in the bonding substrate formation step, the ions implanted to form the damage layer are ions of atoms smaller than atoms forming the first substrate.

Assignees

• Nippon Telegraph & Telephone

Inventors

• Kashiwazaki Takahiro
• Umeki Takeshi
• Kasahara Ryoichi
• Tadanaga Osamu
• Embutsu Koji
• Kazama Takushi

Classifications

• C30B33/06

  Joining of crystals · CPC title

• C30B29/30

  Niobates; Vanadates; Tantalates · CPC title

• G02F1/377 Primary

  in an optical waveguide structure · CPC title

• G02F1/39 Primary

  for parametric generation or amplification of light, infrared or ultraviolet waves · CPC title

• G02B6/29394

  Compensating wavelength dispersion (G02B6/29376 takes precedence; dispersion compensated optical transmission systems H04B10/2507) · CPC title