JPH07120632A - Manufacture of glass waveguide - Google Patents

Abstract

PURPOSE:To suppress the shrinkage of a porous glass at sintering treatment at minimum and prevent the deformation of a base, in a method for manufacturing a glass waveguide by accumulating the porous glass on the base by flame accumulation, then sintering it to form a transparent glass film on the base, and working the transparent glass film. CONSTITUTION:An oxyhydrogen quartz burner 4 different from a porous glass forming quartz burner 3 is arranged, facing the base placing face of a turn table rotated with a base 2 placed thereon, and a porous glass is accumulated on the base 2 by use of the porous glass forming quartz burner 3, and the base 2 is then thermally treated by the oxyhydrogen flame of the oxyhydrogen quartz burner 4. Thus, the bulk density of the porous glass accumulated on the base 2 is improved, and the shrinkage of the porous glass at glassing by the following sintering treatment can be suppressed to the minimum.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for manufacturing a glass waveguide, and more particularly to a method for manufacturing a glass waveguide including a step of forming a porous glass film by a flame deposition method.

[0002]

_2. Description of the Related Art As a technique of this kind, a porous glass is formed by a flame deposition method on a quartz glass substrate or a silicon substrate with a SiO ₂ film, and then the deposited porous glass is sintered to form a transparent glass film. A method is known in which a transparent glass film is formed and processed into a core having a rectangular cross section by photolithography and ion etching to form a glass waveguide.

[0003]

By the way, in the above-mentioned conventional manufacturing method, the density of the porous glass is about 1/8 of that of ordinary glass, and the glass shrinks considerably when it is made into a transparent glass by sintering. The board tends to warp or swell.
Therefore, when the core pattern is transferred by the mask aligner, a focus mismatch occurs on the surface of the substrate, which causes a dimensional variation of the fine core pattern. Also, when the porous glass for cladding is deposited on the core waveguide formed by ion etching, the core shape is deformed due to the contraction of the porous glass for cladding during vitrification, and the desired multiplexing / demultiplexing characteristics are obtained. May not be shown.

Further, due to the influence of the deformation of the substrate and the core shape, the dispersion of the connection loss of each port becomes large when coupling with a multi-core optical fiber, and a low loss glass waveguide type optical device cannot be manufactured.

An object of the present invention is to provide a method for manufacturing a glass waveguide which solves the above-mentioned problems and can suppress the deformation of the core shape and the substrate due to the shrinkage of the porous glass during the sintering process. To do.

[0006]

In order to achieve the above object, in the method for producing a glass waveguide of the present invention, porous glass is deposited on a quartz glass substrate or a silicon substrate with a SiO ₂ film by a flame deposition method. After that, assuming a glass waveguide manufacturing method that includes the step of sintering this to form a transparent glass film on the substrate, the glass raw material gas is reacted in an oxyhydrogen flame to deposit porous glass on the substrate. Place another oxyhydrogen burner that does not supply the glass raw material gas next to the porous glass forming burner to be, the porous glass deposited on the substrate using the porous glass forming burner, of the other burner Characterized by heat treatment with a flame.

In the glass waveguide manufacturing method of the present invention, the substrate is placed on a turntable, and the porous glass forming burner and the other burner are placed on the substrate placement surface of the turntable. It is desirable that the step of depositing the porous glass and the step of depositing the porous glass on the substrate using the quartz burner for forming the porous glass and the step of heat-treating using the other burner be repeated.

[0008]

According to the manufacturing method of the present invention, another oxyhydrogen burner that does not supply the glass source gas is arranged next to the oxyhydrogen burner for forming the porous glass, and the burner for forming the porous glass is used on the substrate. By heat-treating the porous glass deposited on the substrate with another quartz burner described above, the bulk density of the porous glass deposited on the substrate is improved, and the shrinkage during the subsequent vitrification into transparent glass is minimized. It can be suppressed to the limit.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic diagram of a flame deposition apparatus for producing a glass waveguide by the method of the present invention. In the figure, reference numeral 1 is a turntable of the flame deposition apparatus, and the turntable 1 is arranged so that a plurality of substrates 2 are placed in the vicinity of its peripheral portion and rotated at a predetermined rotation speed. Above the peripheral edge of the turntable 1, a quartz burner 3 for forming porous glass, a quartz burner 4 for oxyhydrogen flame, and an exhaust pipe 5 are provided.
Is arranged, and the heater 6 is arranged near the lower surface. The quartz burner 3 for forming porous glass has a quadruple tube structure capable of introducing raw material gases such as PCl ₃ , BCl ₃ and SiCl _{4 into} an oxyhydrogen flame, and flame-hydrolyzes the raw material to produce P ₂ O ₅ -B ₂ O ₃ -SiO ₂ -based fine particles are generated and deposited on the substrate 2. The quartz burner 4 for the oxyhydrogen flame is a burner for generating an oxyhydrogen flame that does not contain the glass raw material gas, and is arranged immediately adjacent to the quartz burner 3 for forming the porous glass. In this case, since it is necessary to heat the surface of the substrate 2 with the quartz burner 4 for the oxyhydrogen flame after depositing the porous glass on the substrate 2, the quartz burner 4 for the oxyhydrogen flame 4 is required.
Is arranged at a position on the downstream side of the quartz burner 3 for forming porous glass with respect to the rotation direction of the turntable 1 (direction of arrow A in the drawing). The exhaust pipe 5 is provided at a position facing the quartz burner 3 for forming porous glass,
The glass particles in the oxyhydrogen flame after being supplied from the quartz burner 3 to the substrate 2 can be sucked and exhausted.
The heater 6 heats the turntable 1 and the substrate 2 being processed.
This is for keeping the temperature of a predetermined temperature. Since the porous glass is deposited only on a specific region of the substrate 2 only by rotating the turntable 1, the turntable 1 is rotated in the horizontal direction (arrow B direction in the drawing) every time the turntable 1 is rotated. The porous glass is deposited on the entire surface of the substrate 2 by reciprocating.

The thickness of this flame deposition apparatus is 1 mm,
An example will be described in which porous glass is formed on a quartz glass substrate having a diameter of 3 inches. In that case, as a previous step, TiO ₂ —SiO _{2 is formed} on the substrate 2 by an electron beam evaporation method.
A glass film is formed to a thickness of 8 μm, and then a core pattern having a width of 8 μm is formed through a photolithography process and an ion etching process. Then, the substrate 2 is placed on the turntable 1 heated to 500 ° C. with the surface on which the core pattern is formed facing up. Then, while the turntable 1 is rotated at a predetermined rotation speed, for example, 10 rpm, the quartz burner 3 for forming the porous glass and the quartz burner 4 for the oxyhydrogen flame are simultaneously used to deposit the flame on the substrate 2 and perform the heat treatment. I do. At that time, each substrate 2 was first exposed to the flame of the quartz burner 3 for forming the porous glass, and the surface thereof had a thickness of 200 μm of P ₂ O ₅ —B ₂ O ₃ —SiO _{2 —.}
After the porous glass is formed, the turntable 1 rotates to move to the oxyhydrogen flame quartz burner 4 side and is exposed to the oxyhydrogen flame. Therefore, the porous glass of each substrate 2 is heat-treated by the oxyhydrogen flame almost at the same time after deposition, and its bulk density is improved. Under the conditions of this example, the bulk density of the porous glass after the heat treatment with the oxyhydrogen flame was 0.7 g / cm ³ . On the other hand, in the conventional method which does not use the quartz burner 4 having only the oxyhydrogen flame, it is as small as 0.2 g / cm ³ . In this way, after the porous glass was deposited on the substrate 2 and sintered in an electric furnace, the glass substrate treated by the method of the present invention had a warpage amount of only 2 μm. It was confirmed that it was significantly improved with respect to 10 μm.

[0012]

In summary, according to the method for manufacturing a glass waveguide of the present invention, the porous glass deposited on the substrate using the porous glass forming burner is used as another oxyhydrogen burner which does not supply the glass raw material. By heat treatment with the flame of
Since the bulk density of the porous glass deposited on the substrate can be improved and the shrinkage during the subsequent vitrification of the porous glass into the transparent vitrification can be minimized, the shrinkage of the porous glass It is possible to manufacture a glass waveguide in which the core shape and the deformation of the substrate are small.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of a flame deposition apparatus used when manufacturing a glass waveguide by the method of the present invention.

[Explanation of symbols]

 1 Turntable 2 Substrate 3 Quartz burner for forming porous glass 4 Quartz burner for oxyhydrogen flame 5 Exhaust pipe

Claims (2)

[Claims] 1. A glass conductor including a step of depositing porous glass on a quartz glass substrate or a silicon substrate with a SiO ₂ film by a flame deposition method and then sintering the porous glass to form a transparent glass film on the substrate. In the method for manufacturing a waveguide, another oxyhydrogen burner that does not supply the glass raw material gas is arranged next to the burner for forming the porous glass that causes the glass raw material gas to react in the oxyhydrogen flame to deposit the porous glass on the substrate. A method for manufacturing a glass waveguide, characterized in that a porous glass deposited on a substrate using a porous glass forming burner is heat-treated with a flame of another burner. 2. The substrate is placed on a turntable, and the porous glass forming burner and the other burner are arranged so as to face a substrate placing surface of the turntable to form the porous glass. The method of manufacturing a glass waveguide according to claim 1, wherein the step of depositing the porous glass on the substrate by using a quartz burner and the step of heat-treating by using the other burner are repeated.