JPS6049301A - Manufacture of light guide - Google Patents

Abstract

PURPOSE:To form a light guide in a simple step with high productivity by diffusing an organometallic compd. into a gel formation, locally irradiating it with UV rays or far UV rays to cause the difference between the refractive indices of the irradiated parts and the nonirradiated parts. CONSTITUTION:A gel formation 21 is prepared from a soln. composed essentially of at least one kind of metal alcoholate, water, and an org. solvent, it is immersed in a soln. 22 contg. an organo-Ge compd. for a prescribed time or more to diffuse said organo-Ge compd. into the gel formation 21. A proper part of the gel formation 21 to be converted into a light guide is irradiated with UV rays or far UV rays 23 by using a low pressure mercury arc lamp or excimer laser or the like to decompose said org. Ge compd. Then, the organo-Ge compd. remaining in the gel formation 21 is removed by heat drying the gel 21. As a result, a light guide having a refractive index distribution is prepared in such a step.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for manufacturing an optical waveguide on the surface of a glass molded article.

[Prior art]

Conventional methods for manufacturing an optical waveguide having a three-dimensional pattern or a refractive index pattern include the following. First, a glass thin film is formed on a substrate using the CVD method or VAD method, and then it is coated on the substrate by using a resist or by reactive sputter etching after passing through a soger coating process, as shown in Part 14. A waveguide /2 having three-dimensional turns is formed. Alternatively, by doping the glass with a dopant at high temperature after depositing a suitable mask by a phosphorography process, a waveguide having a refractive index distribution pattern on a substrate can be formed as shown in FIG. form 3.

However, these methods require precise control of many conditions, such as flow rate control and temperature control of several types of raw material gases. For this reason, the manufacturing equipment became complicated and expensive, and there was a limit to the film formation speed. Furthermore, since there are an extremely large number of steps, there is a problem that mass productivity and economic efficiency are lacking. Furthermore, since high-temperature treatment is required in processes such as doping, it is difficult to hybridize with materials with poor heat resistance such as compound semiconductors.

Therefore, without using the gas phase reaction as described above.

It has been considered to form a glass film waveguide on a substrate using a glass forming method using silicon alkoxide or the like as a raw material and a hydrolysis reaction between this and water. This method is
For example, tetraethoxysilane.

It consists of an extremely simple process in which a solution consisting of alcohol and water is applied onto a substrate, and the solution is gradually dried and heated to gel and vitrify to form a glass film on the substrate. Therefore, there is an advantage that expensive equipment and materials are not required. However, during heating and drying, the bath solution shrinks by about % to %, which causes the formed glass film to separate from the substrate and cause fine cracks to form there. It was difficult to fabricate optical waveguides for practical use because only thin films could be formed.

〔the purpose〕

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to propose a method for manufacturing an optical waveguide that can be produced by a simple process.

[Structure of the Invention] To achieve this, the present invention provides a method for forming an optical waveguide using a gelation reaction of a solution containing a metal alcoholate and water, in which ultraviolet light or vacuum ultraviolet light is irradiated in the gel. germanium, which decomposes to form dolbant;
By mixing an organometallic compound such as tin or lead and locally irradiating it with ultraviolet light or vacuum ultraviolet light, a refractive index difference is created between the unirradiated area and the process is similar to the phosphorography process at a low temperature. To easily form an optical waveguide pattern in the process of

〔Example〕

The invention will now be described in detail with reference to one drawing.

FIG. 2 shows the principle process of the present invention.

In the figure, in process (I), a gel molded product containing a small amount of metal alcoholate, water, and an organic solvent as main components and an organometallic compound mixed therein is prepared. A gel molding 21 is prepared from a solution containing one kind of metal alcoholate, water and an organic solvent as main components (I-D), and then,
Process CI-
TIE').

This causes the organic germanium compound to diffuse into the gel. Alternatively, instead of such a step, another method of mixing the organic germanium compound into the gel is to mix the organic germanium compound into a solution containing metal alcoholate, water and an organic solvent as main components and gel it. Gel molded product containing organic germanium compound 2/
It is also possible to employ a method for producing (process (I-III)).

Next, in process (II), ultraviolet light or vacuum ultraviolet light 23 is irradiated onto a suitable portion of the gel molded product 21 to be used as a waveguide using low-pressure water pot baking or an excimer laser. photodecomposes organic germanium compounds.

Thereafter, in process (e), the organic germanium compound remaining on the gel molded product 2/ is removed.

For this purpose, in this process, the gel molded product is heated and dried (process (m-x)). Alternatively, instead of such a method, a process (nI
-n)), and then heating and drying may be performed. This method is particularly effective when using non-volatile organogermanium compounds. Through the above steps, an optical waveguide having a refractive index distribution can be manufactured.

Here, in the above description, an organic germanium compound has been cited as an example of an organic metal compound that photodecomposes to produce a dopant when irradiated with ultraviolet light or vacuum ultraviolet light. Examples of the modified germanium compounds include alkylgermanium compounds such as tetramethylgermanium and tetraethylgermanium, vinyl group-substituted products thereof, and arylgermanium compounds. However, the present invention is not limited thereto, and instead of the organic germanium compound, it is also possible to use an organic metal compound such as an organic tin compound or an organic lead compound. Among these, organometallic compounds containing metals of the genus, such as organogermanium compounds, organotin compounds, and organolead compounds, are particularly suitable because of their good stability and ease of handling.

The distinction between ultraviolet light and vacuum ultraviolet light in the above explanation is that light having a wavelength shorter than 200 nm is generally referred to as vacuum ultraviolet light. Which of these is used depends on whether or not it has the energy necessary to decompose the organometallic compound used.

Next, after passing through the above-mentioned processes (■) to (1), a process (■) (see FIG. 1) of heating the gel molded product 21 in oxygen to a temperature of 500 DEG C. or higher is performed. As a result, the organic components fixed in the gel produced by the decomposition of the organometallic compound by photolysis in process (■) are oxidatively decomposed and removed. Moreover, the gel molded article 2/, which was in a porous state, is melted and vitrified. As a result, it can be used for a long period of time without causing problems such as absorbing moisture from the atmosphere due to its porous nature, or reducing the stability of the gel molded product due to residual organic components reacting with oxygen in the atmosphere. An optical waveguide with improved reliability and stability can be obtained.

Below, specific examples of the present invention will be described.

〔Example/〕

A solution of tetramethoxysilane, water, and methyl alcohol mixed in a molar ratio of 10:10 was gelled using a mold to produce gel substrates with three thicknesses (process (
I-I)). After thoroughly drying the substrate, immerse it in tetramethylgermanium lj methyl ether rock solution,
Tetramethylgermanium was diffused into the gel (process (I-n)). After that, a width of 20μ on the substrate surface
Using an ArF excimer laser on the linear part of m/
After irradiating with vacuum ultraviolet light from 3 companies (Process (■)), the area was gradually heated and dried (Process (■-I)).As a result, the refractive index of the light-irradiated area was 0.5% higher than that of the non-irradiated area. 00g
The optical waveguide 3.2 was formed on the substrate 3/ as shown in FIG.

[Example]

A solution of tetraethoxysilane, water, ethyl alcohol, and hydrochloric acid mixed in a molar ratio of /:10:10:0.02 was gelled to produce a gel substrate with a thickness of λn (Process (I- 1)').

This is 209 of tetraethylgermanium! + After soaking in ethyl alcohol solution (process (I-II)),
A mask having a groove-shaped hole with a width of 100 μm and 10 curves was attached and irradiated with vacuum ultraviolet light of /glA, 2 nm using a low-pressure mercury lamp (Process <II)). Next, the gel substrate is immersed in carbon tetrachloride and gradually heated, and the carbon tetrachloride is boiled to remove tetraisoprohilgermanium remaining in the gel (mu), followed by slow heating and drying. (Process (m-I)).As a result, the refractive index of the light-irradiated area is Q007 thicker than that of the unirradiated area.
As shown in the figure, a curved waveguide t2 was formed on the substrate.

[Example 3] Tetramethoxysilane, water, methyl alcohol and tetraphenylgermanium molar ratio: 10:1O:
A solution mixed at a ratio of QO8' is gelled to a thickness of -11
A gel substrate of mm was prepared (process CI-m)). After drawing a branch pattern on the surface of this substrate using an ArF excimer laser (process (Il)), the remaining tetraphenylgermanium was removed in boiling carbon tetracarbon (m-n)), and then gradually heated and dried. Ta(
Process (III-I)). As a result, the refractive index of the light irradiated part was larger than that of the unirradiated part by Qθθ2, and an optical branching waveguide 2 was formed on the substrate 2 as shown in FIG.

[Example≠]

Tetramethoxysilane, Tetrainpropoxytitanium,
The molar ratio of water, methyl alcohol and triethylvinyl germanium is -C-/: 0.2:/(1;l:
/ 0 : 0. The mixed solution was gelatinized so as to have a thickness of
m)). After drying, an aluminum mask having groove-shaped holes with a width of 20 μm was attached to this substrate, and vacuum ultraviolet light of /g≠;7nrn was irradiated using a low-pressure mercury lamp (process (■)). Thereafter, it is gradually heated. As a result, the refractive index of the light irradiated part becomes 0ρ/ larger than that of the unirradiated part, and an optical waveguide 12 is formed in the substrate 2/ as shown in FIG. 4. [Effect] As explained above, according to the present invention, a waveguide structure can be formed by directly drawing a pattern on a gel produced by a molding method using ultraviolet light or vacuum ultraviolet light, which is different from conventional methods. In comparison, it has the advantage that waveguides can be manufactured with high productivity. Furthermore, the present invention has the advantage that by using ultraviolet light or vacuum ultraviolet light, a waveguide can be fabricated by a lower temperature process than conventional methods, and since it does not use processes such as etching, the problem of damage to the substrate can be avoided. . Furthermore, since the present invention applies the sol-gel method, it has the advantage that by controlling the composition of the solution, it is possible to easily control properties important for optical components such as refractive index and expansion coefficient. .

Furthermore, according to the present invention, since the gel molded product in which the optical waveguide is formed is heat-treated, it can be used for a long period of time.
An optical waveguide with high reliability and stability can be obtained.

[BRIEF DESCRIPTION OF THE DRAWINGS] The first circuit and (Bl) are perspective views showing the structure of the optical waveguide formed on the substrate, respectively; FIG. 2 is a diagram showing the principle process of the present invention; Figures 1, 2 and 6 are perspective views showing optical waveguides formed according to embodiments of the present invention. //... Substrate 1, /3 /2... Waveguide, 2/ ...Gel molded product (gel substrate), 2 no..organic germanium')um+f[,23...ultraviolet light (vacuum ultraviolet light), 24! ...Light irradiation part, 2.--Organic solvent, 3/, Hiroi, si, ti...Substrate, 32, Hiro 2.3242... Waveguide. Patent Applicant Nippon Telegraph and Telephone Public Corporation IE□＼ ″':'Ir゛1 Representative Patent Attorney Yoshi Tani -if, :... Figure 5 32 1 Figure 6 2

Claims (1)

[Scope of Claims] 1) A first step of producing a gel molded product containing at least seven kinds of metal alcoholates, water, and an organic solvent as main components and mixed with an organometallic compound. A portion of the gel molded product corresponding to the optical waveguide to be formed is irradiated with radiation having energy to photodecompose the organometallic compound, thereby separating the portion of the gel molded product corresponding to the optical waveguide and the remaining portion. an optical waveguide comprising: a second step of forming a refractive index difference between the remaining portions; and a third step of removing an organometallic compound remaining in the remaining portion of the gel molded product. Production method 0 2) A first step of producing a gel molded product containing at least seven kinds of metal alcoholates, water and an organic solvent as main components and mixed with an organometallic compound. A portion of the gel molded product corresponding to the optical waveguide is irradiated with radiation having energy to photodecompose the organometallic compound corresponding to the optical waveguide to be formed on a portion of the gel molded product, and the remaining part of the gel molded product is separated from the part corresponding to the optical waveguide. a second step of forming a refractive index difference between the remaining portions of the gel molding, a third step of removing the organometallic compound remaining in the remaining portion of the gel molding, and heating the gel molding in oxygen. A method for manufacturing an optical waveguide, comprising a step V of treating the gel molded product to remove organic components contained in the gel molded product and vitrifying the gel molded product. 3) In the manufacturing method according to claim M1 or 2, the first step includes gelling a bath solution containing at least seven types of metal alcoholates, water, and an organic solvent as main components, and then A method for producing an optical waveguide, characterized in that the gel molded product is produced by mixing the organometallic compound. 4) In the manufacturing method according to claim 1 or 2, in the first step, a small amount of the organic metal A method for producing an optical waveguide, which comprises mixing a compound and then gelling the bath solution to produce the gel molded product. 3. The method for manufacturing an optical waveguide according to item 1, wherein the third step includes heating and drying the gel molded product. 6) In the manufacturing method according to any one of claims 1 to j, the third step includes immersing the gel molded product in an organic medium for a predetermined time and then heating and drying it. A method for manufacturing a featured optical waveguide. 7) A method of manufacturing an optical waveguide according to any one of claims 1 to 6, wherein the radiation is ultraviolet rays. 8) A method for manufacturing an optical waveguide according to any one of claims 1 to 6, wherein the radiation is vacuum ultraviolet rays. 9) In the manufacturing method according to any one of claims 1 to 1, the organometallic compound is an organometallic compound containing a metal of the group 4 and has a % character of 3b. Wave path σ) Manufacturing method. (Margin below)