JPH04238304A - Production of optical waveguide - Google Patents

Abstract

PURPOSE:To provide the process for producing the optical waveguide which allows the taking of a large change in refractive index, has a nonlinear optical effect, and has a shape, such as slab shape or channel shape, as an org. polymer waveguide having excellent workability. CONSTITUTION:This process for producing the optical waveguide formed with a waveguide part in the part where group II-IV element compd. semiconductor superfine particles of element period table are dispersed in an org. polymer as the refractive index of this part is higher than the refractive index in the circumference is the process for producing the optical waveguide by forming patterns 2 for forming the waveguides on the precursor org. polymer 1 contg. the group II metal element compd. to be the raw material for the semiconductor superfine particles, then bringing a gaseous group VI element compd. necessary for forming the semiconductor superfine particles into reaction thereby dispersing the semiconductor superfine particles into the selected parts, i.e., the waveguide shapes.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to an optical waveguide characterized by having an optical waveguide portion having a refractive index larger than that of the surrounding area due to semiconductor ultrafine particles being selectively dispersed in an organic polymer. Regarding the manufacturing method.

Optical waveguides are extremely useful for easily branching and coupling optical fibers and for performing nonlinear optical operations such as optical switches.

0003

2. Description of the Related Art Research on optical circuits used in the fields of optical communications and optical information processing has made rapid progress in recent years, and among these, the development of optical waveguides has been remarkable.

[0004] Optical waveguides include organic polymer optical waveguides as well as inorganic crystals made of LiNbO3 with Ti diffused therein and glasses made of metals exchanged with other metals through ion exchange.

A conventional method for manufacturing an organic polymer waveguide is to apply lithography to form an optical waveguide pattern. In other words, after creating an organic polymer film containing a monomer, selectively irradiating it with ultraviolet rays using a patterning mask. There is a method of polymerizing to change the refractive index, or a method of forming a waveguide with a high refractive index by laser scanning (Japanese Patent Laid-Open No. 63-91604).

Conventionally, in the formation of optical waveguide patterns using lithography, problems have been pointed out such as yellowing of the resin competing with the crosslinking reaction caused by ultraviolet irradiation, and deterioration of the material due to swelling of the organic polymer during etching. There is. As a way to overcome this, for example, JP-A-64-59
No. 302 discloses a method of performing etching treatment by exposure using water instead of an organic solvent. However, it is said that such a method using exposure and etching processing still has many problems, especially when it comes to producing an organic polymer optical waveguide.

[0007] For organic polymer nonlinear optical waveguides, poling (electric field orientation) treatment is used, in which an electric field is applied near the softening point temperature or glass transition point of the polymer to change the orientation of the polar low molecules contained therein. There are organic polymer waveguides that have been treated to align. In this method, a lower electrode is provided by lithography, a buffer layer is formed thereon, and an organic polymer in which a nonlinear optical compound such as methylnitroaniline is dispersed is coated. By applying a patterned electrode on top of this and applying voltage to the electrode,
It is a waveguide with a nonlinear optical effect in which the methylnitroaniline present in the electrode application part is polarized and oriented, and a part with a high refractive index is formed compared to the surrounding non-oriented part (R.Ly
tel et al., SPIE Proceedings No. 824, p. 152, 1987).

[0008] However, there are disadvantages in that the orientation of the molecules, which is essential for developing the required refractive index, may disappear due to changes over time, and that it is necessary to apply an electric field to maintain the orientation. Furthermore, since it is based on the orientational polarization effect of molecules, it has the disadvantage that it is difficult to obtain a large refractive index difference.

[0009]

[Problems to be Solved by the Invention] The present inventors have conducted research to solve the above-mentioned problems in the prior art all at once, and have developed optical waveguides, especially integrated patterns that have nonlinear optical effects. We have discovered a new method for manufacturing an organic polymer optical waveguide, and have accomplished the present invention.

The present invention relates to a method for manufacturing an optical waveguide having an optical waveguide portion having a larger refractive index than the surrounding area by selectively dispersing semiconductor ultrafine particles in an organic polymer. When forming an optical waveguide by dispersing semiconductor ultrafine particles into selective parts by reacting a reactive gas necessary for producing semiconductor ultrafine particles with a precursor organic polymer containing a metal element compound, which is the raw material for the The present invention provides a method for manufacturing an optical waveguide, which comprises printing a pattern for forming a waveguide on a precursor organic polymer using a resin solution.

According to the method of the present invention, the exposure process using a photosensitive resin or the etching process using a solvent is omitted, so there is no risk of deterioration of the material during the manufacturing process. In addition, since materials with different refractive indexes are dispersed to form an optical waveguide, it is possible to avoid a decrease in the refractive index difference due to the elimination of orientation polarization due to changes over time, and since the effect is not due to polarization, it is possible to improve the filling factor. A large refractive index change can also be imparted.

Furthermore, the semiconductor ultrafine particles are spatially
It is known that when the thickness is less than about 100 angstroms, the electronic state is subject to a confinement effect and a large nonlinear performance is exhibited, further increasing the usefulness.

[0013]

[Means for Solving the Problems] An optical waveguide manufactured by the present invention will be explained with reference to FIG. As shown in the cross-sectional view d) in FIG. 1, the optical waveguide according to the present invention has semiconductor ultrafine particles selectively dispersed in patterned parts of an organic polymer containing a metal compound to guide the optical waveguide. It has a sectional structure.

Next, the manufacturing method of the present invention will be described based on FIG. First, a precursor organic polymer containing a metal element compound that is a raw material for semiconductor ultrafine particles is prepared.

As metal element compounds, compounds of Groups II-VI of the Periodic Table of Elements are used for the production of semiconductor ultrafine particles.
Group II element compounds such as cadmium perchlorate, zinc acetate, and lead nitrate are used.

As the organic polymer, an organic polymer having excellent optical properties such as transparency, such as polymethyl methacrylate, polyacrylonitrile, polycarbonate, polystyrene, etc., or a mixture or copolymer containing one or more of these, is used. .

These metal element compounds and organic polymers are dissolved in a suitable solvent. For example, polar organic solvents such as dimethylformamide, acetonitrile, methanol, and tetrahydrofuran are preferably used from the viewpoint of solubility of metal elements and organic polymers.

The solution thus prepared is developed by casting or spin coating onto a suitable substrate such as glass or silicon. The contained solvent is removed by air drying or reduced pressure treatment to form a precursor organic polymer film.

A pattern for forming a waveguide is printed on the precursor organic polymer film thus obtained using a resin solution. Here, the resin solution refers to a resin solution dissolved in a solvent capable of dissolving an organic polymer, such as dimethylformamide, acetonitrile, methanol, acetone, benzene, etc., or a plasticizer, such as dimethyl phthalate, tributyl phosphate, etc. The resin used is butyral resin, SBR resin, melamine resin, acrylic resin, natural rubber, or a composition based on these. This resin solution is patterned onto the precursor organic polymer to make it adhere and adhere, and printing means such as screening printing is appropriately employed for patterning.

Depending on the purpose, the reactive gas required for the generation of semiconductor ultrafine particles may be a Group VI element compound gas such as hydrogen sulfide gas or hydrogen selenide gas, or a gas obtained by diluting these with an inert gas such as nitrogen or helium. , or a mixture of these gases in an arbitrary ratio. The reactive gas is selectively absorbed and dissolved in large amounts in the printed resin solution pattern area, and in the process of diffusing into the contacting precursor organic polymer, semiconductor ultrafine particles are generated, compared to the non-patterned area. A waveguide with a high refractive index is formed.

If necessary, it is also possible to adjust the particle diameter or density of the semiconductor ultrafine particles produced by adjusting the concentration of the metal element compound and the amount of solvent remaining in the precursor organic polymer.

Since the nonlinear optical effect of the semiconductor ultrafine particle dispersion utilizes the spatial confinement effect of electrons and holes generated by light absorption, the particle diameter is preferably controlled to about 10 to 1000 angstroms.

According to the method of the present invention, it is possible to obtain planar waveguides, channel waveguides, and waveguide composite structures.

[0024]

[Examples] The present invention will be explained in more detail with reference to Examples below. Example 1 3.5 ml of a dimethylformamide solution in which 1.0 x 10 -4 mol of cadmium perchlorate Cd(ClO4)2 .6H2O and 0.5 g of acrylonitrile/styrene copolymer resin were uniformly dissolved was placed in a glass Petri dish with a diameter of 70 mm. expand. Put this in a vacuum desiccator, 1To
The solvent is removed by leaving it at room temperature for one day under reduced pressure of rr to obtain a precursor organic polymer film. The thickness of this film was 90 μm. A linear pattern was formed on this precursor organic polymer film by coating using a solution of butyral resin dissolved in dimethylformamide as a resin solution. This was left for 2 hours in a hydrogen sulfide atmosphere to obtain a channel waveguide. Visible and ultraviolet absorption spectra and electron microscopy photographs of the produced cadmium sulfide semiconductor ultrafine particles confirmed that selective dispersion of the semiconductor ultrafine particles into the patterned areas had been achieved. The confinement effect of traveling light by a waveguide is achieved by using a helium-neon laser, and an incident light beam having an inclination of approximately 10 degrees with respect to the linear direction of the waveguide within the film plane is confined within the waveguide and propagated. This confirmed the formation of an optical waveguide.

Comparative Example 1 The same procedure as in Example 1 was carried out except that pattern formation using dimethylformamide-containing butyral resin was not performed, and the formation of semiconductor ultrafine particles was confirmed by visible/ultraviolet absorption spectra and electron micrographs. However, no effect of guiding the incident laser light in a specific direction was observed.

[0026]

[Effects of the Invention] Organic polymer optical waveguides are expected to be highly versatile due to their good processability and ease of handling.Although the present invention is a novel method, it is extremely simple and effective. A method for manufacturing a waveguide is provided. The optical waveguide produced by the method of the present invention not only functions as a waveguide, but also has nonlinear optical performance.
Its usefulness will be even higher in optical switches and the like. In addition, it has the effect of overcoming the problem of the waveguide disappearing due to the cancellation of polarization that occurs over time, as in the case of a poling polymer waveguide. Furthermore, since the present invention uses a printing method such as coating or screening printing for pattern formation, it has the effect of significantly expanding the variety of optical waveguide circuit formation. The present invention greatly contributes to improving the characteristics of optical circuits and has great industrial significance.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating a method for manufacturing an optical waveguide according to the present invention. a) is a precursor organic polymer; b) is a patterned precursor organic polymer; c) is a patterned precursor organic polymer; and d) is a cross-sectional view of a manufactured optical waveguide.

[Explanation of symbols]

1. Precursor organic polymer, 2. Pattern for waveguide formation using resin solution, 3. Reactive gas, 4. Semiconductor ultrafine particle dispersion portion: Optical waveguide portion (high refractive index portion) 5.. Low refraction. rate part.

Claims (1)

[Claims] Claim 1: In an optical waveguide in which semiconductor ultrafine particles are dispersed in selective parts in an organic polymer, and the refractive index of the part is higher than that of the surrounding area to form an optical waveguide, a metal serving as a raw material for semiconductor ultrafine particles is used. When dispersing semiconductor ultrafine particles into selective parts that will become optical waveguides by reacting a precursor organic polymer containing an elemental compound with a reactive gas necessary for producing semiconductor ultrafine particles, the precursor organic polymer is mixed with a resin solution. A method for manufacturing an optical waveguide, comprising printing a pattern for forming a waveguide.