JPS62111214A - Production of optical waveguide consisting of glass film with optical fiber - Google Patents

Abstract

PURPOSE:To decrease the connection loss to optical fibers and to eliminate the change of a transmission characteristic by external atmosphere by including a stage for depositing pulverized core glass particles by a thermal oxidation reaction or hydrolysis reaction on a glass substrate, heating the same to a high temp. and vitrifying the particles to transparent glass. CONSTITUTION:The optical fiber 4 of the length projecting from the side part of the starting glass quartz substrate 3 is embedded in a guide groove 32 for connection along said groove. The pulverized glass particles are then deposited on the substrate 3 by using a glass prepd. by mixing a refractive index increasing dopant such as geCl4 with SiCl4 which is the essential raw material for glass as a glass raw material for the glass. The deposited particles are heat-treated at a high temp. to form the transparent core glass 5 consisting of GeO2-SiO2. Etching is thereafter so executed that only the core glass 5 formed in the grooves of the pattern to be used as the core for the optical waveguide remains. The pulverous glass particles to be formed as the clad glass are deposited on the substrate 3 by a deposition method for pulverized glass particles using SiCl4 as the glass raw material for the glass in succession thereof and is sintered at a high temp.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing an optical waveguide, and particularly to a +IA manufacturing method for a glass film optical waveguide with an optical fiber.

[Prior Art] A conventional method for manufacturing a glass film optical waveguide is shown in FIGS.
This will be explained with reference to the process diagram of f).

First, a porous glass 32 that will become a GeO2-SiO2-based core layer is deposited on a quartz glass substrate 31 (Fig. 3(a)
)). The deposition of the porous glass 32 involves the deposition of 5
A glass particle deposition method is used in which a raw material gas containing iCfLa mixed with GeO2 as a refractive index increasing dopant is subjected to a hydrolysis reaction or a thermal oxidation reaction in an oxyhydrogen flame to obtain glass particles. 5iC on this porous glass 32
Porous glass 33 of 5i02 serving as a clad layer is deposited by a glass particle deposition method using Q4 as a raw material gas (FIG. 3(b)).

Next, this is heat-treated at a high temperature of about 1500° C. to make the porous glass 32 and 33 transparent glass, and the core glass 34. Form the clad glass 35 (Fig. 3(C)
). Through the above steps, a silica glass multilayer film is formed in which the core glass 34 having a high refractive index is sandwiched between glasses having a relatively low refractive index.

Furthermore, Si or T is formed on the surface of the clad glass 35.
i etc metal 1! ! J36 is coated by sputtering or vapor deposition (FIG. 3(d)). Then, this metal film 36 is removed by photolithography leaving a desired metal pattern 37 (FIG. 3(e)). Next, the core glass 34 and cladding glass 35 are etched using the metal pattern 37 as a mask, and then the metal pattern 37 is removed (FIG. 3(f)). In this way, an optical waveguide with a desired pattern is formed.

FIG. 4 is a perspective view of the input/output portion of the glass optical waveguide device manufactured by the above manufacturing process.

A guide groove 42 is formed to facilitate optical connection with the optical fiber 41. The optical fiber 41 is inserted along this guide groove 42, and the optical waveguide 43 having the core glass 34 as a core is connected to the optical fiber 41.

[Problems to be Solved by the Invention] As a method of connecting the optical waveguide 43 and the optical fiber 41, there is a method of fusion splicing by irradiating the joint portion of the two with CO2 laser light. is absorbed by the quartz-based glass and the glass component evaporates instantly, making it difficult to perform low-loss fusion splicing.

Furthermore, when attempting to use the discharge fusion method, which is often used to connect optical fibers, it is difficult to perform fusion splicing because the difference in heat capacity between the optical fiber 41 and the quartz glass substrate 31 is large. .

By the way, in Japanese Patent Laid-Open No. 59-202407, a porous glass layer formed by depositing glass particles on a glass substrate is locally cut by laser beam irradiation until it reaches the substrate glass, and then the remaining part is cut into a transparent glass layer. A method is disclosed for forming a waveguide by using a laser beam, and an example is given in which a groove for a connecting fiber is cut with a laser beam at the porous film stage. However, it is difficult to efficiently and strongly connect the waveguide and the optical fiber simply by inserting the optical fiber into the fiber groove of the transparent vitrified waveguide.

Furthermore, since the side surface of the leading waveguide 43 is in contact with the air in FIG. 4, there is a problem that the transmission characteristics change depending on the external atmosphere such as water vapor condensation.

[Object of the Invention] The object of the present invention is to solve the problems of the prior art described above, and to provide a glass film optical waveguide with an optical fiber, which reduces connection loss with an optical fiber and whose transmission characteristics do not change due to external atmosphere. The purpose of this invention is to provide a method for manufacturing the same.

[Summary of the Invention] In order to achieve the above object, the present invention includes a first step of forming a concave optical waveguide pattern and a guide groove for embedding a connecting optical fiber on a glass substrate, and A second step of embedding a length of optical fiber protruding outward from the side surface of the glass substrate, and depositing core glass fine particles on the glass substrate by thermal oxidation reaction or hydrolysis reaction, which are then heated to a high temperature to become transparent glass. a fourth step of removing core glass other than the core glass formed in the optical waveguide pattern from the transparent vitrified core glass; and a thermal oxidation reaction or A method for producing a glass film optical waveguide with an optical fiber by a method comprising a fifth step of depositing fine particles of Tallard glass having a refractive index lower than that of the core glass through a hydrolysis reaction, and heating the fine particles at a high temperature to turn them into transparent glass. It is.

[Example] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIGS. 1(a) to 1(f) are process diagrams showing an embodiment of the method for manufacturing a glass film optical waveguide with an optical fiber according to the present invention. First, a convex pattern 11 is formed so as to form a pattern of a guide groove for connecting a required optical waveguide pattern and an optical fiber.
A sol solution 2 made of an alkoxide of a glass-forming element is poured onto a transfer mold 1 having a glass-forming element (FIG. 1(a)). As a material for the transfer mold 1, for example, Pyrex glass is suitable. Furthermore, if the surface of the transfer mold 1 is coated with a release agent, it will be easier to remove the sol 2 from the mold 1 when it becomes a gel. 1411 ot as sol liquid 2 of glass raw material
%5i (OCH:+) 4 and 28 so1% 1120
By using a solution having a composition of 58 mo1% Cf130H, a transparent glass substrate without cloudiness can be obtained. Next, when the hydrolysis of the sol liquid 2 is completed, an agar-like wet gel is obtained. This wet gel has a concave pattern formed in accordance with the pattern 11 of the mold 1. After drying the wet glue at room temperature, it is heat-treated at a high temperature of about 1300° C. while flowing He and O2 to obtain a transparent starting quartz glass substrate 3 (FIG. 1(b)).

Through the above steps, a starting quartz glass substrate 3 having a waveguide pattern 31 and a fiber connection guide groove 32 is obtained. FIG. 1(C) is an enlarged view showing a portion of a guide groove 32 for connection with an optical fiber formed in the starting quartz glass substrate 3. FIG. A length of optical fiber 4 protruding from the side of the starting quartz glass substrate 3 is embedded along the connection guide groove 32.

In this case, the core of the optical fiber 4 and the fi3 which becomes the optical waveguide
A pattern is formed in advance in the transfer mold 1 so that the numbers 1 and 1 coincide with each other.

Next, a glass particle deposition method is used in which glass raw material gas is ejected together with oxygen gas and hydrogen gas by a gas ejection means (not shown), and a hydrolysis reaction or thermal oxidation reaction is carried out in an oxyhydrogen flame caused by oxygen gas and hydrogen gas. , the frit gas is deposited on the glass substrate 3 as glass fine particles. In other words, GeCft is added to 5i (J4), which is the main raw material of glass.
Using a gas mixed with a refractive index increasing dopant such as a as a glass raw material gas, glass fine particles were deposited on the starting quartz glass substrate 3 in which the optical fiber 4 was embedded.
A transparent core glass 5 of Ge02-5i02 is formed by heat treatment at a high temperature of .degree. C. (FIG. 1(d)). After that, a core glass 5 is formed in the groove of the pattern that will become the core of the leading waveguide.
Etching is performed so that only a small portion remains (Fig. 1 (e))
. Etching methods include, for example, CFa and CBrF.
If a reactive sputter etching method using a reactive gas such as No. 3 is used, the etching rate can be increased.

Next, by the glass fine particle deposition method described above, 5iCQ
Glass fine particles to become clad glass are deposited on the substrate 3 using a as a glass raw material gas.

Further, as a frit gas, F3CQ3. G
A mixture of eCff1a, PCQ3, etc. may also be used. In this case, the advantage arises that the softening point is lowered. Further, it is sintered at a high temperature of about 1400° C. to obtain transparent rad glass 6 (FIG. 1(f)).

An example of a Y-shaped valve switch obtained by the above manufacturing method is shown in FIG. Since the connecting optical fiber 4 is attached, it can be connected to other optical fibers with low loss by the electrical discharge fusion method, which is technically established as a method for connecting optical fibers together. Furthermore, since the core glass 5, which is an optical waveguide, is embedded in the clad glass 6, the transmission characteristics will not change due to external atmosphere such as condensation of water vapor.

[Effects of the Invention] As explained above, according to the present invention, the following excellent effects are exhibited.

(1) Since it is possible to manufacture an optical waveguide element with a connecting optical fiber, it is possible to connect it to other transmission optical fibers with low loss by a discharge fusion method or the like.

(2) The core glass through which light is transmitted is embedded in clad glass and is not in contact with air.
Transmission characteristics do not change due to external atmosphere such as water vapor condensation.

[Brief explanation of drawings]

FIGS. 1(a) to (f) are process diagrams showing an embodiment of the method for manufacturing a glass film optical waveguide with optical fiber according to the present invention, and FIG. 2 is a perspective view of a Y-shaped valve manufactured according to the present invention. Figure, Figure 3 (
a) to (f) are process diagrams showing a conventional method for manufacturing a glass film optical waveguide, and FIG. 4 is a perspective view of an input/output portion of a glass optical waveguide element manufactured by the conventional manufacturing method. In the figure, 1 is a transfer mold, 2 is a sol solution of glass-forming elements,
3 is a glass substrate, 4 is an optical fiber, 5 is a core glass, 6
3 is a clad glass, 31 is a waveguide pattern, and 32 is a guide groove.

Claims (3)

[Claims] (1) A first step in which a concave optical waveguide pattern and a guide groove for embedding a connecting optical fiber are formed on a glass substrate.
a second step of embedding a length of optical fiber protruding outward from the side surface of the glass substrate in the guide groove; depositing core glass fine particles on the glass substrate by thermal oxidation reaction or hydrolysis reaction; a third step of heating the glass at a high temperature to make it transparent vitrified; a fourth step of removing core glass other than the core glass formed in the optical waveguide pattern from among the transparent vitrified core glass; A fifth step of depositing fine particles of clad glass having a refractive index lower than that of the core glass on the substrate by thermal oxidation reaction or hydrolysis reaction, and heating the fine particles at high temperature to make transparent glass. A method for manufacturing a glass film optical waveguide with an optical fiber. (2) in the first step, a sol solution of a glass forming element is poured onto a transfer mold having a convex pattern of the optical waveguide pattern and the guide groove, and gel glass is obtained by a hydrolysis reaction; 2. The method of manufacturing a glass film optical waveguide with an optical fiber according to claim 1, which comprises performing a high temperature heat treatment after drying the gel glass. (3) The method for manufacturing a glass film optical waveguide with an optical fiber according to claim 2, wherein the glass-forming element is an alkoxide.