JPH0566314A - Formation of optical waveguide - Google Patents

Abstract

PURPOSE:To provide the method for formation of an optical waveguide with which a high light power is obtainable from a small stimulating light power. CONSTITUTION:This method includes a stage for forming an amorphous layer 2 on the surface of a substrate 1 consisting of a single crystal, a stage for irradiating the part to be formed with the optical waveguide of the amorphous layer 2 with a laser beam and scanning the substrate and the laser beam relatively at a high speed along the optical waveguide to melt the optical waveguide, a stage for gradually weakening the power of the laser beam in the state of the high-speed scanning to crystallize the neighborhood of the lower part of the amorphous layer to a single crystal, and a stage for further weakening the power of the laser beam in the state of the high-speed scanning to crystallize the entire part of the optical waveguide to the single crystal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an optical waveguide, and more particularly to a method for forming an optical waveguide using a wavelength tunable solid-state laser to reduce the excitation power oscillation threshold.

[0002]

2. Description of the Related Art In an optical waveguide used as a basic element of an optical IC or an optical sensor, light (electromagnetic waves) is totally reflected at the boundary surface in a region surrounded by a medium having a low refractive index. It is an optical transmitter that propagates while repeating. As a material for such an optical waveguide, a wide fluorescence spectrum (λ = 700-
A wide band variable wavelength laser can be realized by using Ti: Al ₂ O ₃ having a wavelength of 1100 nm).

FIG. 2 is a diagram showing an example of the configuration of a variable wavelength laser device using an optical waveguide. Excitation light 10 from an excitation light source (not shown) has a wavelength-selective mirror having a spherical surface.
(For example, wavelengths near 500 nm are transmitted, but 700 to 1
(A wavelength near 000 nm is reflected) 11 and enters an optical waveguide 12 made of a laser medium (Ti: Al ₂ O ₃ ), and emits from the opposite side of the optical waveguide to produce a mirror having the wavelength selectivity. -11 Spherical mirror with the same function as -1
Through 3. Laser medium (Ti: Al ₂
O ₃ ) Fluorescence generated inside (wavelength: 650-1000n
m) is reflected by the spherical mirror 13, further reflected by the first resonator 14 and follows the opposite path, and the light reflected by the half mirror 11 passes through the wavelength selection element 15 and is transmitted through the second resonator mirror. Reflects at 16. Therefore, the wavelength between the first and second resonator mirrors 11 and 16 is selected by the wavelength selection element 15 (for example, 700
(nm) only reciprocates. Here, for oscillation, the power density of the excitation light in the laser medium must exceed a certain threshold. And in order to obtain high optical power density, Ti:
When Al ₂ O ₃ is used as an optical waveguide structure, it has a small pumping power.
It is possible to obtain high optical power density.

[0004]

Conventionally, Ti: Al₂O
₃The laser medium shown in Fig. 3 is used as a laser medium.
Do type is known. High light with small excitation light power
Confine excitation light to a narrow area to obtain power density
Although it is necessary, the rod type is made by processing a bulk material.
Since it is manufactured, there is a limit to narrowing the excitation light region. T
i: Al₂O₃In order to form the optical waveguide of
Like Ti: Al₂O ₃With a patterned single crystal film of
The core is made and its single crystal film has a low refractive index and no light absorption
It is necessary to have a clad layer structure covered with a material,
No such attempt has been made.

[0005] The present invention has been made in order to solve the above, T on a single crystal substrate of Al ₂ O ₃
i: A method of forming an optical waveguide in which an amorphous layer made of Al ₂ O ₃ is prepared, and only the portion of the amorphous layer to be used as a waveguide is single-crystallized to obtain a high optical power with a small pumping optical power. The purpose is to provide.

[0006]

In order to solve the above-mentioned problems, the present invention provides a step of forming an amorphous layer on a surface of a substrate made of a single crystal, and a step of forming an amorphous layer on a portion where an optical waveguide is to be formed. The step of irradiating the beam to relatively quickly scan the substrate and the laser beam along the optical waveguide to melt the optical waveguide; and the laser beam in the high-speed scanning state. -A step of gradually weakening the power of the beam to single crystallize the lower vicinity of the amorphous layer, and further weakening the power of the laser beam in the state of the high-speed scan to single crystal the entire optical waveguide It is characterized by including a step of performing.

[0007]

[Function] Since the optical waveguide structure is formed by thinning Ti: Al ₂ O ₃ , the excitation light can be confined in an extremely narrow area, and a high optical power density can be obtained with a small excitation light power.

[0008]

1 (a) to 1 (d) are perspective views showing a schematic manufacturing process of an optical waveguide of the present invention. It demonstrates according to a process. Step (a) (See FIG. A) Single crystal Al ₂ O ₃ substrate (hereinafter,
An amorphous Ti: Al ₂ O ₃ layer (hereinafter referred to as an amorphous layer) 2 having a thickness of several μm is formed on the surface of a substrate 1 by a method such as sputtering.

Step (b) The amorphous layer of the substrate 1
The laser beam 3 is radiated from the end on the 2 side, and the
The laser beam 3 and the substrate 1 are relatively moved along the portion to be
Scan at high speed. Step (c) (Refer to Figure c ... The figure shows the state of the XX cross section of Figure b)
(Shown) dissolve the amorphous layer (the part indicated by A) 2
And the substrate 1 that is the bottom of the optical waveguide is also slightly
Dissolved in (part indicated by B). Next, gradually release the laser power.
One of the amorphous layers 2 on the single crystal substrate 1 while weakening each other
The portion (the portion indicated by B) is made into a single crystal (at this time, the optical waveguide
The surface is Ti: Al₂O ₃The layers are in the melt
). Step (d) Gradually weaken the laser power and reduce the entire optical waveguide.
Ti: Al of the body (portion indicated by B ')₂O₃Single crystal layer
To do. Furthermore, an amorphous material is formed on the substrate 1 including the optical waveguide.
Ti: Al₂O₃Are formed by sputtering or the like. to this
The optical waveguide made of a single crystal is surrounded by a member with a small refractive index.
It will be in a state of being caught. In addition, the single crystal substrate is used in this example.
Al as a plate₂O₃Using T as an amorphous layer
i: Al₂O₃However, the present invention is not limited to this example, and other
The material may be.

[0010]

As described in detail above, according to the present invention, an amorphous film and a laser are used to form Ti: Al ₂ O ₃
Since an optical waveguide consisting of is formed, it can be made extremely small compared to the case of a bulk, and a high optical power density can be obtained with a small excitation light power.

[Brief description of drawings]

FIG. 1 is a perspective view showing a schematic manufacturing process of an optical waveguide of the present invention.

FIG. 2 is a diagram showing a configuration example of a general variable wavelength laser device using an optical waveguide.

FIG. 3 is a diagram showing a conventional example of an optical waveguide (rod type).

FIG. 4 is a diagram showing a configuration of an optical waveguide.

[Explanation of symbols]

1 Single crystal substrate (Al ₂ O ₃ ) 2 Amorphous layer (Ti: Al ₂ O ₃ )

Claims (1)

[Claims] 1. A step of forming an amorphous layer on a surface of a substrate made of a single crystal, and a portion of the amorphous layer where an optical waveguide is to be formed is irradiated with a laser beam, and the amorphous layer is irradiated along the optical waveguide. A step of relatively high-speed scanning the substrate and the laser beam to melt the optical waveguide, and gradually weakening the power of the laser beam in the state of the high-speed scanning, near the lower portion of the amorphous layer. And a step of monocrystallizing the entire optical waveguide by further weakening the power of the laser beam in the state of the high speed scan.