JPH06350184A - Thin film waveguide crystal and manufacturing method thereof - Google Patents

Abstract

PURPOSE:To downsize an element as a laser oscillating material which allows wavelength variation in a near infrared area and improve laser oscillating efficiency by doping Ga with Er or Pr at the time of forming an Er or Pr doped perovskite thin film light guide on the surface of perovskite single crystal by sputtering. CONSTITUTION:Undoped perovskite single crystal is expressed as ABAl (A; Ca<2+> or Sr<2+>, B; one selected from Y<3+>, Gd<3+>, La<3+>). A thin film light guide for the crystal is Er or Pr and Ga doped perovskite crystal expressed as ABxLn1-xGayAl O4 (A; Ca<2+> or Sr<2+>, B; Er<3+> or Pr<3+>, Ln; one selected from Y<3+>, Gd<3+> and La<3+>, x; 0.001<=x<=0.2, y:0.01<=x<=0.1). A sintered body adjusted to have such quantity ratios is used as a target. Thus, the crystal provided with the thin film light guide which allows the downsizing of an element and efficient laser oscillating efficiency is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is useful as a light-emitting material, and in the field of utilizing coherent light such as optical measurement, optical information processing, optical medical treatment, optical processing, various optical devices such as laser elements and optical amplifiers. The present invention relates to an erbium- or praseodymium-rare-earth-doped perovskite optical waveguide crystal which is effective in reducing the size and efficiency of an element and coupling with a fiber, and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, a semiconductor for a laser is known as an optical waveguide crystal. Also, in non-semiconductors, for example,
LiNdO ₃ waveguide crystal added with Nd as an optical waveguide formed by using an ion exchange method, KTiOPO
₄ crystals are known.

The thin-film optical waveguide formed by the sputtering method is a Y ₃ Ga ₅ O containing Nd or Cr.
₁₂ (M.YAMAGA et al, Japanese Journal of Applied Ph
ysics.23,312 (1984), Journal of Luminesence 39,335
(1988)) is known. In addition, an optical waveguide prepared by ion implantation is Nd: Y _{3 produced} by He ⁺ ion implantation.
Al ₅ O ₁₂ (SJField et al, IEEE Journal of QUANTU
M Electoronics 27,423 (1991), PJChandler et al,
Nuclear Instruments and Methods in Physics Researc
h B59 / 60,1223 (1991)), KNb by He ⁺ ion implantation
O ₃ (D.Flick et al, Applied Physics Letter 59,3213
(1991)), C ⁺ ion implanted sapphire (PDTowns
end et al, Electronics Letter 26, 1193 (1990)) are known.

However, the composition formula AB _{x is formed} on the perovskite type single crystal substrate represented by the composition formula ABAlO ₄ of the present invention.
Ln _1-x Ga _y AlO ₄ in the rare earth-doped perovskite thin film waveguide crystals grown perovskite thin film crystal represented is not known.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides an Er-doped perovskite single crystal useful as a wavelength tunable laser oscillation material or as an up-conversion laser in the near infrared region (1500-1650 nm) and 1050-1.
PROBLEM TO BE SOLVED: To provide a crystal having a thin film optical waveguide, which is a Pr-doped perovskite single crystal useful as a lasing material at 200 nm or as an up-conversion laser, and which enables device miniaturization and high lasing efficiency, and a manufacturing method thereof There is something aimed at.

[0006]

As a result of various studies to achieve the above object, the inventors of the present invention have found that Er or Pr-doped perovskite thin film waveguides are sputtered on the surface of a perovskite single crystal. To form
The thin film formed by co-doping these with Ga is T
obtained by i alone doping (refractive index of about 1.93 to 1.9
The present invention has been completed based on the finding that the refractive index of the thin film crystal is higher than that of 6).

That is, the present invention is based on the composition formula ABAlO ₄ (A:
Ca ²⁺ or ^{Sr 2+, B: Y 3+,} Gd 3+, the perovskite single crystal substrate represented by the selected one element) from a composition formula _{AB x Ln 1-x Ga y} AlO 4 (A: Ca ²⁺ or S
r ²⁺ , B: Er ³⁺ or Pr ³⁺ , Ln: Y ³⁺ , Gd ³⁺ , L
one selected from a ³⁺ , x: 0.001 ≦ x ≦ 0.2,
The present invention relates to a rare earth-doped perovskite thin film waveguide crystal obtained by growing a perovskite thin film crystal represented by y: 0.01 ≦ y ≦ 0.1).

Next, the present invention will be described in detail. The perovskite type single crystal used as the substrate in the present invention has a composition formula AB
AlO ₄ (A: Ca ²⁺ or Sr ²⁺ , B :: Y ³⁺ , G
It is an undoped perovskite type single crystal represented by (a type selected from d ³⁺ and La ³⁺ ). The crystalline thin film waveguide of the present invention is a perovskite crystal co-doped with Er or Pr and Ga, and has a composition formula of AB _x Ln _1-x Ga _y AlO ₄ (A:
Ca ²⁺ or Sr ²⁺ , B: Er ³⁺ or Pr ³⁺ , Ln:
One selected from Y ³⁺ , Gd ³⁺ and La ³⁺ , x: 0.00
1 ≦ x ≦ 0.2, y: 0.01 ≦ y ≦ 0.1).

The crystal thin film waveguide of the present invention has a thickness of 1 to 1.
0 .mu.m, the refractive index of the thin film waveguide portion is 1.980-1.
It is around 990. If the film thickness of this thin film portion is unnecessarily thin, the waveguide is not formed, and if it is too thick, the waveguide mode becomes multimode, which is not preferable. A film thickness of 2 μm or less is preferable for making the waveguide a single mode, and the refractive index in this case is 1.990 or less.

Further, the thin film waveguide portion has the composition shown by the above composition formula. In the composition formula, when x is less than 0.001, the active ion concentration is low and the emission intensity is weak.
When it is larger than 2, the emission is weak due to concentration quenching. Further, when y is smaller than 0.01, the difference in refractive index is small and the wave guide layer is not formed. When y is larger than 0.1, the multi-waveguide mode is formed.

A method for manufacturing the rare earth-doped perovskite thin film waveguide crystal of the present invention will be described below. The substrate used in the manufacturing method of the present invention has the composition formula ABAl as described above.
O _{4 (} A: Ca ²⁺ or Sr ²⁺ , B :: Y ³⁺ , Gd ³⁺ , La
It is an undoped perovskite type single crystal represented by (a type selected from ³⁺ ).

The thin film waveguide is formed on the surface of this single crystal by the sputtering method using the following target. That is, Ca ²⁺ or Sr ²⁺ (A) carbonate or oxide, Er ³⁺ or Pr ³⁺ (B) oxide, Y ³⁺ , Gd ³⁺ ,
One kind of oxide selected from La ³⁺ (Ln), and oxides of Ga ³⁺ and Al ³⁺ are prepared by A: B: Ln: Ga: Al (atomic ratio) = 1: x: 1-x: y: 1-y (where x: 0.
001 ≦ x ≦ 0.2, y: 0.01 ≦ y ≦ 0.1) is adjusted and the sintered body is used as a target.

For the sputtering at this time, a normal rf sputtering method is used, and the sputtering gas is an inert gas, for example, an Ar gas atmosphere of 10 ⁻³ to 10 ⁻⁴ torr. Also, it is preferable to heat the substrate during sputtering,
A thin film waveguide is formed directly on the surface of a single crystal when it is heated to 700 ° C. or higher and sputtered. However, when the temperature is lower than 700 ° C., the thin film formed has an amorphous portion and is crystallized. For this purpose, the desired rare earth-doped perovskite thin film waveguide crystal can be obtained by heating and aging at 1200 ° C. or higher in an oxidizing, reducing, or inert atmosphere.

[0014]

EXAMPLES The present invention will now be described in more detail with reference to Examples.

Example 1 A plate-shaped single crystal of perovskite of the composition formula CaYAlO ₄ was used as a substrate, and CaC was used as a sputtering target.
_{O 3, Er 2 O 3,} Y 2 O 3, Ga 2 O 3, Al 2 O 3
In an atomic ratio of Ca: Er: Y: Ga: Al = 1: 0.0
Using a sintered body adjusted to 2: 0.98: 0.05: 0.95 and sintered, 4 × 10 −4 torr of Ar was used for the substrate 8.
It was heated to 00 ° C. and sputtered at 10 A / min. The thickness of the thin film portion of the obtained crystal was 1.2 μm.
Further, the thin film portion had almost the above composition as a result of elemental analysis by an X-ray microanalyzer. Further, it was confirmed by electron diffraction that the thin film portion was Er-doped perovskite.

Example 2 Using the plate-like single crystal used in Example 1 as a substrate, CaC
_{O 3, Pr 2 O 3,} Y 2 O 3, Ga 2 O 3, Al 2 O 3
In an atomic ratio of Ca: Pr: Y: Ga: Al = 1: 0.0
Sputtering was performed in the same manner as in Example 1 except that the sintered body was adjusted to 2: 0.98: 0.05: 0.95 and sintered, and the substrate was heated to 600 ° C. The thin film portion of the obtained crystal was placed at 1750 ° C. in an Ar atmosphere containing 0.5% hydrogen.
min Heat aged. The thickness of the obtained thin film is 1.5μ.
It was m. The thin film portion was a perovskite containing Pr as a result of the same analysis as in Example 1.

Example 3 Using the plate-shaped single crystal used in Example 1 as a substrate, CaC
O ₃ , Er ₂ O ₃ , La ₂ O ₃ , Ga ₂ O ₃ , Al ₂ O
₃ in an atomic ratio of Ca: Er: La: Ga: Al = 1: 0.
Sputtering was performed in the same manner as in Example 1 except that a sintered body obtained by adjusting the ratio to 02: 0.98: 0.05: 0.95 and sintering was used. The thin film portion of the obtained crystal had a thickness of 1.5 μm. This thin film portion was analyzed in the same manner as in Example 1 and the result E
It was a perovskite containing r.

[0018]

INDUSTRIAL APPLICABILITY The rare earth-doped perovskite optical waveguide crystal having the constitution of the present invention has a high laser oscillation efficiency and can be used as a small wavelength tunable laser and an optical amplifying device.

[0019]

Claims (4)

[Claims] 1. A composition formula ABAlO ₄ (A: Ca ²⁺ or Sr
²⁺ , B: Y ³⁺ , Gd ³⁺ ), a composition formula AB _x Ln _1-x on a perovskite type single crystal substrate represented by
_{Ga y AlO 4 (A: Ca} 2+ or Sr ^2+, B: Er ³⁺ or ^{Pr 3+, Ln: Y 3+,} Gd 3+, one selected from La ^3+, x: 0.001 ≦ x ≦ 0.2, y: 0.01 ≦ y ≦
0.1) A rare-earth-doped perovskite thin film waveguide crystal obtained by growing a perovskite thin film crystal. 2. The composition formula ABAlO ₄ (A: Ca ²⁺ or Sr
²⁺ , B: Y ³⁺ , Gd ³⁺ , a perovskite-type single-crystal substrate represented by the formula A) (Ca ²⁺ or Sr
²⁺ ) carbonate or oxide, B (Er ³⁺ or Pr ³⁺ ) oxide, Ln (one selected from Y ³⁺ , Gd ³⁺ , La ³⁺ )
Oxides of Ga ³⁺ and Al ³⁺ with A: B: L
n: Ga: Al (atomic ratio) = 1: x: 1-x: y: 1-
y (where x: 0.001 ≦ x ≦ 0.2, y: 0.0
(1 ≦ y ≦ 0.1) A rare earth-doped perovskite thin film waveguide crystal characterized by forming a thin film by a sputtering method using a sintered body that is adjusted and sintered as a target. Law. 3. A perovskite type single crystal substrate is heated to 700 ° C. or higher using Ar gas to perform sputtering.
The manufacturing method described. 4. A rare earth-doped perovskite thin film waveguide crystal obtained by heating a perovskite type single crystal substrate at a temperature of less than 700 ° C. to obtain a rare earth-doped perovskite thin film waveguide crystal at 1200 ° C. or higher in an oxidizing or reducing atmosphere or an inert atmosphere. The manufacturing method according to claim 2, wherein the heating is carried out.