JPS6066210A - Method of manufacturing optical waveguide - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to an optical waveguide, and particularly to a method for manufacturing a multimode optical waveguide using a glass ion exchange method.

(b) Conventional technology In order to manufacture optical waveguides for optical branching, etc., the conventional methods were: 1. burying the waveguide in a substrate by drawing an electric field through glass ion exchange, 2. manufacturing a waveguide with a semicircular cross section by thermal diffusion. A method is used in which the film is formed on a substrate, and the two substrates are not bonded to each other facing each other.

The optical waveguide manufactured by the method (■) above is shown in Figure 1 (
As shown in a), since an optical waveguide with a circular cross section is formed in the glass substrate 1, an ideal optical waveguide can be obtained. A glass substrate is coated with high temperature silver nitrate (AgNO3).
After immersing the glass substrate in a molten salt such as KNO3 to perform glass ion exchange and forming an optical waveguide on the surface of the glass substrate, the glass substrate is removed from the molten salt, and then the substrate is immersed again in another molten salt such as KNO3. However, since the waveguide section is drawn into the substrate by applying an electric field again, there is a drawback that manufacturing is extremely troublesome and time-consuming.

In addition, as shown in FIG. 2, in the method (2) above, a glass substrate 3 on which an optical waveguide 4 having a semicircular cross section is formed is bonded with two wedges of adhesive 5 so that the optical waveguide 4 faces each other. Since the optical waveguide 4 is manufactured by using the optical waveguide, the adhesive 5 is located in the center of the optical waveguide 4, and when light passes through the optical waveguide, light scattering occurs and the loss increases.

(c) Purpose The purpose of the present invention is to solve the above-mentioned drawbacks of the conventional optical waveguide manufacturing method, to provide an optical waveguide that can be manufactured relatively easily, and that the manufactured optical waveguide has little loss. An object of the present invention is to provide a method for manufacturing a wave path.

(D) Structure In order to achieve the above object, the method for manufacturing an optical waveguide of the present invention includes immersing a glass substrate provided with electrodes on the entire surface of one side and mask pattern electrodes on the other surface in a molten salt, A voltage is applied between the mask pattern electrode and the glass substrate to perform sufficient glass ion exchange to the extent that a high refractive index portion having a semicircular cross section is formed in the non-mask portion of the glass substrate, and then Glass of the same quality as the glass substrate is bonded to the surface of the glass substrate where the high refractive index portion is exposed (
E) Examples The present invention will be explained in more detail with reference to Examples below.

In the embodiment shown below, as shown in FIG. 3(a), a case will be described in which an optical branching waveguide 12 consisting of a main waveguide 13 and branching waveguides 15 and 16 is formed on a glass substrate 11.

In the manufacturing process, as shown in FIG. 4, first, a full-surface electrode 18 is provided on one side of a glass substrate 11 such as soda lime glass or BK-7, and a mask pattern electrode 19 is provided on the other side.
This glass substrate 11 is immersed in a high temperature molten salt 21 filled in a tank 20, and a voltage V is applied between the electrodes 18 and 19.
is applied to perform glass ion exchange. When the application of the voltage V continues, the metal ions in the molten salt 21 penetrate into the glass substrate 11 from the non-mask portion 19a of the mask pattern 19, and eventually a semicircular high refractive index portion 22 is formed. . If glass ion exchange is continued from this point on and the electric field is continued to be applied, the high refractive index portion 22 having a semicircular cross section will be drawn toward the inside of the glass substrate 11, and the high refractive index portion 22 will be drawn into the glass substrate 11.
2 has a bell-like shape instead of a semicircular shape.

When the bell-shaped high refractive index portion 22 is formed on the glass substrate 11, the glass substrate 11 is taken out from the molten salt 21 in the tank 2o, the surface of the glass substrate 11 is thoroughly cleaned, and then the bell-shaped high refractive index portion 22 is formed. A glass plate 16 made of the same material as the glass substrate 11 is attached to the side on which the index portion 22 is formed using an adhesive 17.

Through the above process, the main waveguide 13 with a bell-shaped cross section
, the optical branching waveguide 12 consists of branching waveguides 15 and 16,
It is formed on a glass substrate 11.

The cross-sectional shape of the optical branching waveguide obtained as described above is
Although it is not circular, it is bell-shaped, and since no adhesive is located in the center of the optical waveguide, light propagating within the waveguide propagates without suffering loss due to scattering or the like.

Note that although the cross-sectional shape is not circular, if the mode of the propagating light is multimode, there is no problem that the cross-sectional shape is not completely circular, and good light propagation can be obtained as a whole.

(f) Effects According to this invention, since glass ion exchange is performed only once, an optical waveguide can be manufactured in a relatively short time.
In addition, the cross-sectional shape of the optical waveguide is formed into a bell shape, and the optical waveguide is constructed by pasting a glass plate with adhesive to the bottom of the bell shape. Since the propagating light does not undergo scattering, it is possible to obtain a multimode waveguide with low loss and stable characteristics.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an optical waveguide obtained by a conventional optical waveguide manufacturing method, in which FIG. 1(a) is a plan view, FIG. 1(b) is a side view, and FIG. FIG. 2 is a diagram (not showing an optical waveguide manufactured by another conventional manufacturing method);
a) is a perspective view of the same optical waveguide, FIG. 2(b) is a side view of the same optical waveguide, and FIG. Figure 3 (a
) is a perspective view of the optical waveguide, FIG. 3(b) is a side view of the optical waveguide, and FIG. 4 is a diagram showing the inside of a tank for explaining an embodiment of the present invention. 11: glass substrate, 12: optical branching waveguide, 16: glass plate, 17: adhesive, 18: electrode, 19: mask pattern electrode patent applicant
Shimadzu Corporation Representative Patent Attorney Shigeru Nakamura Figure 1 (C7) (b) 11 -1?3

Claims (1)

[Claims] (1) A glass substrate with an electrode on the front surface of one side and a mask pattern electrode on the other side is immersed in molten salt, a voltage is applied between the entire surface electrode and the mask pattern electrode, and a voltage is applied to the non-mask portion of the glass substrate. , perform glass ion exchange sufficiently to the extent that a high refractive index portion having a semicircular cross section is formed, and then apply a material of the same material as the glass substrate to the surface of the glass substrate where the high refractive index portion is exposed. A method for manufacturing an optical waveguide in which a glass plate is attached.