JPH07159640A - Production of optical waveguide - Google Patents

Abstract

PURPOSE:To provide a process for production of optical waveguides by which the optical waveguides having arbitrary shapes are easily and efficiently obtainable. CONSTITUTION:This process for production has a stage for installing a mold formed with a groove 11 corresponding to the optical waveguide into a solvent 14, a stage for charging silica particulates 15 for a core into this solvent 14 and packing the silica particulates 15 for the core into the groove 11 by gravity settlement, a stage for charging silica particulates 17 for a clad into the solvent 14 and depositing these silica particulates 17 for the clad on the mold packed with the silica particulates 15 for the core into the groove 11 by gravity settlement, a stage for taking the mold deposited with the silica particulates 17 for the clad out of the solvent 14 and obtaining an optical waveguide pattern body 19 by removing the mold and a stage for forming the optical waveguide by subjecting the optical waveguide pattern body 19 to a transparent vitrification treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manufacturing method for manufacturing an optical waveguide used in the fields of communication and optics.

[0002]

2. Description of the Related Art A conventional optical waveguide is manufactured by sequentially forming a clad layer and a core layer on a substrate by a CVD method or the like, patterning the core layer by a photolithography technique, and further forming a clad layer thereon. This is done by forming layers.

The method using this photolithography technique can manufacture an optical waveguide having an arbitrary structure, but the number of steps required until an optical waveguide is obtained is very large and complicated, so that the above method is used. Manufacturing efficiency is low.

On the other hand, the extrusion molding method disclosed in Japanese Patent Laid-Open No. 4-124042, Japanese Patent Laid-Open No. 4-12404.
The pressure molding method disclosed in Japanese Patent Laid-Open No.
A method of manufacturing an optical waveguide by using a powder molding method such as a casting molding method disclosed in Japanese Patent Laid-Open No. 4-56331 has also been studied.

However, the method using the powder molding method is suitable for efficiently manufacturing a linear optical waveguide for an optical fiber, but it is necessary to manufacture an optical waveguide having a complicated structure such as intersections and branches. I can't. The present invention has been made in view of the above points, and an object of the present invention is to provide a method for manufacturing an optical waveguide, which can easily and efficiently obtain an optical waveguide having an arbitrary shape.

[0006]

Means for Solving the Problems The present invention comprises the steps of placing a mold having grooves corresponding to an optical waveguide in a solvent, and introducing silica-based fine particles for a core into the solvent to spontaneously precipitate the particles. Filling the groove with silica-based fine particles for the core, and adding the silica-based fine particles for the clad to the solvent and allowing the silica-based fine particles for the core to be filled in the groove by spontaneous precipitation to form the clad on the mold. For depositing silica-based fine particles for use, removing the mold on which the silica-based fine particles for cladding are deposited from the solvent, and removing the mold to obtain an optical waveguide pattern body, and transparent glass for the optical waveguide pattern body. And a step of forming an optical waveguide by subjecting it to an optical waveguide.

Here, the silica-based fine particles for core and clad used in the present invention are spherical particles synthesized by a vapor phase synthesis method or a sol-gel method, and their particle diameter is sufficiently smaller than the pattern width of the optical waveguide. , I.e. submicron particles well below the width of the mold grooves can be used.

In particular, silica-based fine particles having a uniform particle size and having a uniform particle size are preferable because they are easy to be packed most closely when they are naturally settled in the grooves of the mold. Furthermore, by using silica-based fine particles having a single particle size, the shrinkage factor during the transparent vitrification treatment does not vary, and an optical waveguide without distortion or bending can be manufactured. Such a silica-based fine particle having a single particle size,
W. Stober, A. Fink and E. Bohn, J. Collo. Interface Sc
i., 26, 26 (1968) and the like, and can be synthesized by utilizing the hydrolysis method of alkoxide.

When synthesizing silica-based fine particles for a core having a single particle diameter, an element for controlling the refractive index such as Ge, P, Ti and Al may be added, and the optical waveguide is provided with a function such as an amplification effect. A rare earth element such as Er may be added for the purpose of imparting.

The solvent used in the present invention includes
Ethyl alcohol, methyl alcohol and the like can be used. Further, as the material of the mold used, polyvinyl alcohol (PVA), polyvinyl butyral (PV
Resins such as B), paraffin, barley, rubber and the like can be used. When producing a mold having a groove, injection molding, compression molding or transfer molding using the above-mentioned mold material may be used, or a mold body may be prepared from the above-mentioned mold material and the groove may be formed therein.

In the present invention, when a resin is used as the material of the mold, a method of removing the mold can be a method of heating the mold to burn it off or melt it, or a method of immersing the mold in a solvent to elute it. By removing the mold by such a method, the optical waveguide pattern body can be obtained without damage. The transparent vitrification treatment performed in the present invention is performed at 1000 to 1200 ° C in a He atmosphere.

[0012]

According to the method of manufacturing an optical waveguide of the present invention, a mold in which a groove corresponding to the optical waveguide is formed is placed in a solvent, and the silica-based fine particles for the core are put into this solvent to spontaneously settle in the groove. It is characterized in that the silica-based fine particles for clad are charged and spontaneously settled to be deposited, and the optical waveguide pattern obtained by removing the mold is subjected to a transparent vitrification treatment.

According to this method, if the groove corresponding to the optical waveguide pattern can be formed in the mold, an optical waveguide having a complicated structure such as branching and crossing can be obtained. Therefore, it is suitable for manufacturing an optical waveguide having a fine pattern. Moreover, since the deposited layer can be formed only by spontaneously precipitating the silica-based fine particles, the optical waveguide can be efficiently manufactured by a relatively simple manufacturing process. Further, by making the particle diameters of the silica-based fine particles uniform, the shrinkage during the transparent vitrification treatment becomes uniform, and an optical waveguide without distortion or bending can be obtained.

[0014]

Embodiments of the present invention will be specifically described below with reference to the drawings. 1A to 1H are process drawings for explaining one embodiment of the method of the present invention.

First, a female die 12 having a groove 11 corresponding to a required optical waveguide pattern is prepared. At this time, the dimensions of the groove 11 are set so as to have a desired shape after the transparent vitrification treatment in consideration of shrinkage in the transparent vitrification treatment. Then, as shown in FIG.
Is placed in the container 13 so that the groove 11 opens upward, and ethyl alcohol is charged as the solvent 14.

Then, as shown in FIG. 1 (B), the solvent 1
Silica-based particles for core 1 having a single particle size of about 0.3 μm in 4
Add 5 and stir after standing. Then female 1
As shown in FIG.
As shown in (C), the core deposition layer 16 is formed.

Then, the female die 12 is taken out of the solvent 14 to remove the deposited layer deposited on the region other than the groove 11, and is placed again in the solvent 14, and the solvent 1 is removed as shown in FIG. 1 (D).
The silica-based fine particles 17 for clad having a single particle diameter of about 0.5 μm are put into 4 and the mixture is left standing after stirring. Female 12
The silica-based fine particles 17 for cladding are allowed to spontaneously settle on the core deposition layer 16 in the groove 11 to form a cladding deposition layer 18 as shown in FIG. 1 (E). At this time, the core deposition layer 1
Strictly speaking, 6 and the clad deposition layer 18 are in a state as shown in FIG.

Then, as shown in FIG. 1G, the female die 12 is taken out from the solvent 14, dried and then heated at a temperature of about 700 ° C. to burn off the female die 12, and at the same time, the core deposition layer 16 and the clad deposition are deposited. Layer 18 is calcined, FIG.
An optical waveguide pattern body 19 as shown in (H) is obtained.

Next, the optical waveguide pattern body 19 is placed in the solvent 14 with the core deposition layer 16 facing upward, and the silica-based fine particles for cladding having a single particle diameter of about 0.5 μm are placed in the solvent 14. It is charged and a clad deposition layer is formed in the same manner as described above. After that, this is taken out from the solvent and dried, and then subjected to a refining treatment in a He, Cl ₂ atmosphere at 900 ° C. and a transparent vitrification treatment in a He atmosphere at 1100 ° C. in order to manufacture an optical waveguide.

In this embodiment, the silica-based fine particles having a single particle size are synthesized in advance and put in a solvent, but they may be directly precipitated while being synthesized in a container. The former is suitable for strictly controlling the deposition amount of silica-based fine particles, and the latter is suitable for simplifying the process.

Further, in this embodiment, the deposited layer formed by natural sedimentation is used as it is. However, after the deposited layer is formed, the packed layer is pressed by, for example, uniaxial pressing to fill the packed layer. May be adjusted or the adhesiveness of the particles forming the deposited layer may be improved.

Further, in this embodiment, one female mold is placed in a solvent to manufacture an optical waveguide, but a plurality of female molds are placed in a solvent to simultaneously manufacture a plurality of optical waveguides. Good. Alternatively, a plurality of grooves corresponding to the optical waveguide pattern may be formed in one female type, a plurality of optical waveguides may be manufactured at a time, and then cut out to manufacture a plurality of optical waveguides in one step. it can.

[0023]

As described above, according to the method of manufacturing an optical waveguide of the present invention, a mold having grooves corresponding to the optical waveguide is placed in a solvent, and silica-based fine particles for cores are added to the solvent. It is allowed to spontaneously settle and fill the groove, and the silica-based fine particles for clad are added, and the particles are allowed to spontaneously settle and deposited, and the optical waveguide pattern obtained by removing the mold is subjected to transparent vitrification treatment, so branching, crossing, etc. It is possible to easily and efficiently obtain an optical waveguide having a complicated structure of.

[Brief description of drawings]

1A to 1H are process drawings for explaining an embodiment of the method of the present invention.

[Explanation of symbols]

11 ... Groove, 12 ... Female type, 13 ... Container, 14 ... Solvent, 1
5 ... Silica-based particles for core, 16 ... Core-deposited layer, 17 ... Silica-based fine particles for clad, 18 ... Clad deposited layer, 19
... Optical waveguide pattern body.

Claims (3)

[Claims] 1. A step of placing a mold in which a groove corresponding to an optical waveguide is formed in a solvent, and adding silica-based fine particles for a core to the solvent to spontaneously settle the silica-based fine particles for a core to the groove. And a step of charging the silica-based fine particles for cladding into the solvent and depositing the silica-based fine particles for cladding on the mold in which the silica-based fine particles for core are filled in the groove by spontaneous precipitation. A step of taking out the mold in which the silica-based fine particles for cladding are deposited from the solvent and removing the mold to obtain an optical waveguide pattern body; A method of manufacturing an optical waveguide, comprising: 2. The method for producing an optical waveguide according to claim 1, wherein the silica-based fine particles for core and clad have a uniform particle size and are spherical. 3. The method for producing an optical waveguide according to claim 1, wherein a resin mold is used as the mold, and the mold is removed by burning or melting by heating, or by elution with a solvent.