JP2599497B2 - Flat plastic optical waveguide - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic optical waveguide, and more particularly to a flat plastic optical waveguide that can be used as an optical connector for optical communication or image transmission or an optical component such as a duplexer. It is about.

[Background Art] As a base material of an optical component or an optical fiber, inorganic materials such as quartz glass and multi-component glass are generally used because of a small optical transmission loss and a wide transmission band.

On the other hand, optical components based on plastic have been developed. Plastic optical materials used for these are
Since it has better workability and is easier to handle than inorganic optical materials, it has attracted attention due to the expectation that an optical waveguide having relatively good characteristics can be easily manufactured by using the same. Conventionally, two typical methods for producing a flat plastic optical waveguide are a selective photopolymerization method and a method using a photosensitive resin.

The selective photopolymerization method is to produce a patterned optical waveguide by selectively polymerizing a monomer contained in a polymer and changing the refractive index of the polymerized portion. First, as shown in FIG. 4 (A), a predetermined pattern is formed on the surface of a low-refractive-index monomer-containing polymer sheet or a substrate 11 in which a low-refractive-index monomer such as methyl acrylate is contained in a transparent polymer such as polycarbonate. The mask 12 having the low refractive index monomer is selectively polymerized according to the pattern of the mask 12 by irradiating the mask 12 with the ultraviolet light 13. The refractive index of the polymerized portion of the polymer sheet is lower than that of the high refractive index polymer base material. Next, as shown in FIG. 4 (B), the polymer sheet is heated in a vacuum to remove the unreacted monomer 14 in a portion that has not been exposed to ultraviolet light. As a result, the unexposed portion is only a polymer having a high refractive index. In this way, a patterned sheet 16 in which the high refractive index portion serving as the core 15 is formed in a predetermined pattern is obtained. And finally, FIG. 4 (C)
As shown in (1), the patterned sheet 16 is made into a component by sandwiching it with a clad 17 made of a low refractive index polymer.

On the other hand, in a production method using a photosensitive resin, the photosensitive resin is exposed in a pattern, selectively crosslinked, and an unexposed portion is removed by development to obtain a core pattern. First, as shown in FIG. 5A, a polymer 22 to be a lower clad is applied on a substrate 21 by dip or spin coating. Next, as shown in FIG. 5B, a polymer 23 such as a urethane resin containing a photosensitive cross-linking agent is applied on the clad 22 in the same manner. Next, the mask
24, UV light is applied to the applied polymer 23 in a pattern
To crosslink selectively. Next, the substrate is immersed in a solvent to remove unexposed portions, thereby obtaining a pattern of the core 26 as shown in FIG. 5 (C). Finally, as shown in FIG. 5 (D), the upper clad 27 is formed by dipping, spin coating or laminating the clad material to make a part.

In order to obtain a practical optical component with a small optical loss, it is necessary in the production of an optical waveguide that the optical waveguide film be of good quality and that the pattern formed by fine processing be highly reliable. That is, it is preferable that the material has a small optical loss and the film thickness and the refractive index can be controlled with high precision. On the other hand, in microfabrication, it is important that the core side wall has high smoothness, dimensional stability, and high reproducibility.

[Problems to be Solved by the Invention] When a plastic material is used, both the selective photopolymerization method and the method using a photosensitive resin have a low wavelength (0.48 to 1.
1 μm), the loss is relatively low, but due to the harmonics of the infrared vibration absorption of the carbon-hydrogen bond that constitutes the plastic, the near infrared region (1.3 to 1.55) currently used in optical communication is present.
μm), the optical loss is as high as 0.5 to 10 dB / cm, which is not practical. Further, addition of a crosslinking agent or the like also causes an increase in light loss.

In addition, with respect to microfabrication, both methods are simpler and easier to manufacture than glass waveguides.
However, in the selective photopolymerization method, there is a problem that the monomer content changes depending on the volatilization condition of the solvent, and the change in the refractive index slightly fluctuates. On the other hand, the method using a photosensitive resin has problems that the resolution is poor due to swelling at the time of development, and that the surface tends to be uneven. These factors also cause high light loss of the conventional plastic optical waveguide.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a flat plastic optical waveguide having low loss in a visible light to near-infrared light region.

[Means for Solving the Problems] To achieve the above object, a flat plastic optical waveguide according to the present invention includes a core portion made of a polymer containing deuterium or a halogen atom, a core portion surrounding the core portion, and A flat plastic optical waveguide having a clad portion made of a polymer having a low refractive index, wherein the core portion is made of a deuterated or halogenated polyacrylate having a chemical structure represented by the following general formula (I) as a repeating unit. There is a feature.

Further, the invention provides a substrate and a substrate formed sequentially on the substrate,
A lower clad portion, a core portion, and an upper clad portion surrounding the core portion together with the lower clad portion, each core comprising a polymer or copolymer of deuterated or halogenated polyacrylate; Alternatively, it is characterized by comprising a polymer or copolymer of a halogenated siloxane and a polymer or copolymer of a deuterated or halogenated styrene.

[Operation] In the flat plastic optical waveguide according to the present invention, the polymer in the core portion contains deuterium or a halogen atom. Therefore, the flat plastic optical waveguide according to the present invention has extremely excellent optical transmission characteristics in the visible to near-infrared light region as compared with the conventional optical waveguide. It is also possible to control the difference in refractive index between the core and the clad by the halogen atom content.

[Embodiment] The largest factor of the optical transmission loss of plastic is a harmonic of infrared vibration absorption of a carbon-hydrogen bond that shines on plastic. The plastic optical waveguide according to the present invention is obtained by substituting hydrogen in a plastic structure with a halogen atom such as fluorine or deuterium in order to reduce harmonics caused by the carbon-hydrogen bond and to shift the wavelength to a longer wavelength side. is there. As a result, the loss of the material itself can be reduced, and the performance of the optical waveguide can be improved.

Such an optical waveguide can be obtained by forming a resist pattern on a plastic film formed on a substrate by lithography, and performing dry etching using oxygen or a fluorine-based gas using the resist pattern as a mask. That is, a resist is applied on the polymer to be processed, and ultraviolet rays, electron beams, X-rays and the like are irradiated in a pattern. Next, development is performed by immersion in a solvent to obtain a pattern. Using this pattern as a mask, the pattern is transferred to the underlying polymer by reactive dry etching of fluorine or oxygen gas.

An optical waveguide can be manufactured by combining these steps. Typical process steps are shown in FIGS. 1 (A) to 1 (G). First, a clad material is applied to the substrate 1 to form a layered clad 2 (FIG. 1A).
A core material made of an organic polymer is applied on the clad 2,
The core layer 3 is formed (FIG. 1 (B)). Next, as shown in FIG. 1C, a silicone resin-based resist 4 is applied on the core layer 3 and irradiated with ultraviolet rays 6 via a mask 5. Thereafter, development is performed to obtain a mask pattern (FIG. 1 (D)), and reactive ion etching using oxygen gas is performed to remove the core layer other than the pattern portion (FIG. 1 (D)).
(E). The resist is stripped (FIG. 1 (F)), and finally the same clad material 7 as the clad 2 is applied or laminated (FIG. 1 (G)).

In this manufacturing method, a pattern having high resolution and dimensional stability and steep and flat side walls can be obtained by reactive ion etching, and the number of steps is small and the reproducibility is excellent.

A method in which a plurality of optical waveguides are simultaneously formed on a large-area substrate and formed using a stamper (die) has an advantage in terms of mass productivity and can be used.

The optical waveguide propagates light in the core using the difference in the refractive index between the core and the clad. In the case of a plastic optical waveguide, a refractive index difference can be generated by using different types of plastics for the core and the clad. Further, the value of the refractive index can be controlled by the fluorine content in the resin. FIG. 2 shows the change in the refractive index depending on the fluorine content in the copolymer of deuterated heptafluoroisopropyl methacrylate and deuterated methyl methacrylate. The straight line A has a wavelength of 0.6328 μm and the straight line B
Is the refractive index for light with a wavelength of 1.5230 μm, and in each case the refractive index decreases linearly with increasing fluorine content.

Example 1 Heptafluoroisopropyl methacrylate d-520 mol% which is a monomer in which five hydrogens are replaced by deuterium
And a monomer mixture of 80 mol% of perdeuteromethyl methacrylate in which all the hydrogens of methyl methacrylate are replaced with deuterium are polymerized using 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator, A united product (refractive index n = 1.46) was obtained. Further, heptafluoroisopropyl methacrylate-d5 was polymerized using AIBN as a polymerization initiator to obtain a polymer (n = 1.37).

A waveguide having the former polymer as a core component and the latter polymer as a cladding component was produced. First, the two types of polymers described above were each treated with 1,3-bis (trifluoromethyl)
It was dissolved in benzene to form a solution. Next, a clad component polymer solution was applied on a silicon substrate so that the thickness after drying was about 10 μm. After the substrate is heated to 90 ° C. and the coating layer is dried, the core component polymer solution is applied on the clad component polymer for about 8 hours.
It was applied to a thickness of μm.

Next, a silicone-based photoresist was applied and exposed and developed to form a resist pattern. Further, reactive ion etching with oxygen gas is performed to remove the core component polymer other than the pattern portion, and the core component polymer is 50 mm long and 80 mm wide.
It was processed into a linear rectangular pattern having a height of 8 μm and a height of 8 μm. The substrate was immersed in an alkaline solution to remove the resist, and finally the same clad layer as the lower layer was applied. The thickness of the upper cladding was 10 μm on the core.

Light was irradiated from one end of the waveguide thus manufactured, and the light loss of the waveguide was calculated by measuring the amount of light coming out of the other end. FIG. 3 shows the wavelength dependence of optical loss. The optical loss of this waveguide at 1.3μm wavelength is 0.1dB / c
m or less.

Example 2 A waveguide was manufactured by another method using the same two kinds of polymers as in Example 1. First, two kinds of polymers were dissolved in 1,3-bis (trifluoromethyl) benzene to form a solution. Next, a clad component polymer was applied on the silicon substrate to a thickness of about 15 μm to form a clad. After the drying treatment, a silicone-based resist was applied on the clad and exposed and developed.
Further, reactive ion etching of oxygen gas is performed, and the width 8
A groove having a thickness of 6 μm and a depth of 6 μm was provided.

Next, the resist was peeled off, and a core material was applied to a thickness of 10 μm. Back etching was then performed by reactive ion etching of oxygen gas to remove the core material outside the groove. Finally, apply the same clad material as the lower clad to a thickness of 10μ.
m.

Through this process, a waveguide having a core of a linear rectangular pattern having a length of 50 mm, a width of 8 μm, and a height of 6 μm was obtained. Wavelength 1.3
The optical loss of the waveguide was calculated by irradiating μm light from one end of the waveguide and measuring the amount of light coming out of the other end.
The optical loss of this waveguide was 0.1 dB / cm or less.

Example 3 A polymer was obtained by hydrolyzing phenyltrichlorosilane d-5 in which five hydrogens of a phenyl group were replaced by deuterium, dissolving the obtained OH compound in toluene, adding KOD and refluxing, and obtaining a polymer. Was. The obtained polyphenylsilsesoxane (n = 1.56) was used as a core component. Polymethylsilsesquioxane (n = 1.48) obtained by a similar process using methyltrichlorosilane d-3 in which three hydrogens of a methyl group are replaced by deuterium instead of phenyltrichlorosilane d-5 An optical waveguide having as a cladding component was produced. The manufacturing process will be described below.

Each of the above two polymers was dissolved in methyl isobutyl ketone to form solutions. First, a clad component polymer was applied on a silicon substrate to a thickness of about 10 μm. After drying, the core component polymer is about 8 μm on the cladding component polymer.
To a thickness of Next, apply a photoresist with a film thickness,
Patterned. Using this resist as a mask, CF ₄ + H ₂
Reactive ion etching with a gas was performed to process the core into a linear rectangular pattern having a length of 50 mm, a width of 8 μm, and a height of 8 μm. The resist was removed, and finally the same clad material as the lower clad was applied.

Light having wavelengths of 1.3 μm and 1.5 μm was irradiated from one end of the waveguide, and the light loss of the waveguide was calculated by measuring the amount of light emitted from the other end. The optical loss of this waveguide is 0.1 dB / cm or less with respect to each of the above-mentioned wavelengths, so that it can be sufficiently provided to various optical circuits.

Example 4 A polymer was obtained by hydrolyzing phenyltrichlorosilane d-5, dissolving the obtained OH compound in toluene, adding KOD and refluxing. A waveguide was prepared using the obtained polyphenylsilsesquioxane as a core component (n = 1.56) and polymethylsilsesquioxane similarly obtained from methyltrichlorosilane d-3 as a cladding component (n = 1.48). did. Each of the above two polymers was dissolved in methyl isobutyl ketone to form solutions. First, a cladding component polymer was applied on a silicon substrate to a thickness of about 10 μm. After the bake drying treatment, a fluorine-based polymer was applied to a thickness of about 9 μm on the clad component polymer. Next, a silicone resist was applied and patterned. Using this as a mask, reactive ion etching is performed with oxygen gas to a length of 50 m.
m, a width of 8 μm, and a height of 9 μm. The resist was removed, and the core component was poured into the groove.
After the drying treatment, the fluorine polymer was dissolved with a solvent to obtain a core pattern. The resist was removed, and finally the same clad material as the lower clad was applied.

Light having wavelengths of 1.3 μm and 1.5 μm was irradiated from one end of the waveguide, and the light loss of the waveguide was calculated by measuring the amount of light emitted from the other end. The optical loss of this waveguide was 0.1 dB / cm or less for each of the above-mentioned wavelengths.

Example 5 A polymer was obtained by hydrolyzing 20 parts of phenyltrichlorosilane d-5 and 5 parts of diphenyldichlorosilane d-105, dissolving the obtained OH compound in toluene, adding KOD and refluxing. An optical waveguide was prepared using the obtained polyphenylsilsesquioxane as a core component (n = 1.58) and polymethylsilsesquioxane similarly obtained from methyltrichlorosilane d-3 as a cladding component (n = 1.48). did. Each of the above two polymers was dissolved in methyl isobutyl ketone to form solutions. First, a clad component polymer was applied on a silicon substrate to a thickness of about 10 μm. After drying, the core component polymer is about 8 μm on the cladding component polymer.
To a thickness of Next, apply a thick film photoresist,
Patterned. Using this resist as a mask, CF ₄ + H ₂
Reactive ion etching with a gas was performed to process the core into a linear rectangular pattern having a length of 50 mm, a width of 8 μm, and a height of 8 μm. The resist was removed, and finally the same clad material as the lower clad was applied.

Light having wavelengths of 1.3 μm and 1.5 μm was irradiated from one end of the waveguide, and the light loss of the waveguide was calculated by measuring the amount of light emitted from the other end. The optical loss of this waveguide was 0.1 dB / cm or less for each of the above-mentioned wavelengths.

Example 6 A plastic optical waveguide having a chemical structure represented by the following general formula (I) as a repeating unit and using a polyacrylate having a different composition as a core and a clad was produced.

Here, X ₁ and X ₂ are each deuterium, or halogen atom, R ₁ is deuterated, one of a CD ₃ group, and a halogen atom, R ₂ is halide represented by C _n Y _{2n + 1} or heavy A hydrogenated alkyl group (Y is a halogen atom or deuterium, n is a positive integer of 5 or less).

Example 1 or 2
Is the same as

Table 1 shows the chemical structure of the polymer used for the core and clad of each optical waveguide, and the loss of each waveguide with respect to light having a wavelength of 1.5 μm. The loss was as low as 0.04 to 0.11 dB / cm.

Example 7 One kind of linear polysiloxane having a chemical structure represented by the following general formula (II) as a repeating unit and / or a ladder-type polysiloxane having a chemical structure represented by the following general formula (III) as a repeating unit A plastic optical waveguide was manufactured using one kind of siloxane as a core and a clad.

Here, R ₃ and R ₄ are each C _n Y _{2n + 1} (Y is a deuterium or a halogen atom, n is a positive integer of 5 or less) or C ₆
Is a Y _5.

The method of manufacturing the plastic optical waveguide is the same as in Examples 3 to 5.

Table 2 shows the chemical structure of the polymer used for the core and clad of each optical waveguide and the loss of each optical waveguide with respect to light having a wavelength of 1.5 μm. II and III in the column of main chain structure in Table 2 correspond to the aforementioned general formulas (II) and (III), respectively. The loss for light with a wavelength of 1.5 μm in each optical waveguide is 0.05
It was extremely low at ~ 0.11dB / cm.

Example 8 A polymer was obtained by hydrolyzing phenyltrichlorosilane d-5, dissolving the obtained OH compound in toluene, adding KOH and refluxing. The polyphenylsilsesquioxane obtained was used as a core component (n = 1.56), and a copolymer of heptafluoroisopropyl methacrylate d-5 and methyl methacrylate d-8 obtained in Example 1 (mixing ratio: 20/8)
A waveguide having a cladding component (n = 1.45) was prepared. Each of the above two polymers was dissolved in methyl isobutyl ketone to form solutions. First, a clad component polymer was applied on a silicon substrate to a thickness of about 10 μm. After drying, the core component polymer is about 8 μm on the cladding component polymer.
To a thickness of Next, apply a thick film photoresist,
Patterned. Using this resist as a mask, CF ₄ + H ₂
Reactive ion etching with a gas was performed to process the core into a linear rectangular pattern having a length of 50 mm, a width of 8 μm, and a height of 8 μm. The resist was removed, and finally the same clad material as the lower clad was applied.

Light having wavelengths of 1.3 μm and 1.5 μm was irradiated from one end of the waveguide, and the light loss of the waveguide was calculated by measuring the amount of light emitted from the other end. The optical loss of this waveguide was 0.1 dB / cm or less for each of the above-mentioned wavelengths.

Example 9 A polymer was obtained by hydrolyzing phenyltrichlorosilane d-5, dissolving the obtained OH compound in toluene, adding it to KOH and refluxing. The obtained polyphenylsilsesquioxane was used as a core component (n = 1.56), and polymethylsilsesquioxane similarly obtained from non-deuterated methyltrichlorosilane was used as a cladding component (n = 1.46).
8) was fabricated. Each of the above two polymers was dissolved in methyl isobutyl ketone to form solutions. First, a clad component polymer was applied on a silicon substrate to a thickness of about 10 μm. After the drying treatment, a core component polymer was applied to a thickness of about 8 μm on the clad component polymer. Next, a thick photoresist was applied and patterned. Using this resist as a mask, reactive ion etching was performed with CF ₄ + H ₂ gas, and the core was 50 mm long, 8 μm wide and 8 μm high.
In a rectangular pattern. The resist was removed, and finally the same clad material as the lower clad was applied.

Light having wavelengths of 1.3 μm and 1.5 μm was irradiated from one end of the waveguide, and the light loss of the waveguide was calculated by measuring the amount of light emitted from the other end. The optical loss of this waveguide was 0.1 dB / cm or less for each of the above-mentioned wavelengths.

Example 10 A flat plastic optical waveguide was produced in the same manner as in Examples 1 to 3, using a halogenated or deuterated polystyrene having a chemical structure represented by the following general formula (IV) as a repeating unit as a core and a cladding material. Was prepared.

Here, Y is a halogen atom or deuterium. Table 3 shows the chemical structure of the polymer used for the core and the clad of each optical waveguide and the loss of each optical waveguide for light having a wavelength of 1.3 μm. The loss of each optical waveguide was as low as 0.06 to 0.09 dB / cm.

Example 11 A polyacrylate having a repeating unit represented by the aforementioned general formula (I) was used as a clad, and the aforementioned general formula (I)
A plate-type plastic optical waveguide was prepared using polystyrene having a repeating unit represented by V) or polyacrylate having a repeating unit represented by the above general formula (II) as a clad.

Table 4 shows the structure of the optical waveguide and the loss with respect to light having a wavelength of 1.3 μm. The light loss was as low as 0.08 to 0.09 dB / cm.

Plastic optical waveguides composed of a deuterated or halogenated acrylate copolymer, a deuterated or halogenated siloxane copolymer and a deuterated or halogenated styrene copolymer for the core or cladding, respectively You can also.

[Effects of the Invention] As described above, the flat plastic optical waveguide according to the present invention has extremely excellent optical transmission characteristics in the visible to near-infrared light region as compared with conventional optical waveguides.

In particular, 650-1600nm used for optical fiber communication
Since the optical waveguide has low loss in the above wavelength range, this optical waveguide can be used by being connected to a multi-component glass or silica-based optical fiber without performing optical / electrical conversion or electrical / optical conversion. For this reason, there is an advantage that an optical signal transmission system such as a local area network which is excellent in economic efficiency can be constituted by optical components manufactured using these optical waveguides.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing each step in an example of the method for producing a plastic optical waveguide according to the present invention. FIG. 2 is a characteristic diagram showing the dependence of the refractive index of polyacrylate on the fluorine content. Is a characteristic diagram showing the wavelength dependence of optical loss of the embodiment of the plastic optical waveguide according to the present invention, and FIGS. 4 and 5 are schematic cross-sectional views each illustrating a manufacturing process of a conventional flat plastic optical waveguide. . 1 ... substrate, 2 ... clad, 3 ... core layer, 4 ... resist, 5 ... Mack, 7 ... clad.

Claims (17)

(57) [Claims] 1. A flat plastic optical waveguide comprising: a core portion made of a polymer containing a deuterium or halogen atom; and a clad portion surrounding the core portion and made of a polymer having a lower refractive index than the core portion. Wherein the portion is a deuterated or halogenated polyacrylate having a repeating unit of a chemical structure represented by the following general formula (I): However, X ₁ and X ₂ are each deuterium, or halogen atom, R ₁ is deuterated, halogenated or deuterated CD ₃ group, and one of a halogen atom, R ₂ is represented by C _n Y _{2n + 1} Alkyl group (Y is a halogen atom or deuterium, n is 5
The following positive integer). 2. A flat plastic optical waveguide comprising: a core portion made of a polymer containing a deuterium or a halogen atom; and a cladding portion surrounding the core portion and made of a polymer having a lower refractive index than the core portion. Wherein the portion is a deuterated or halogenated polyacrylate of a copolymer comprising two or more different repeating units in the chemical structure represented by the following general formula (I): : However, X ₁ and X ₂ are each deuterium, or halogen atom, R ₁ is deuterated, halogenated or deuterated CD ₃ group, and one of a halogen atom, R ₂ is represented by C _n Y _{2n + 1} Alkyl group (Y is a halogen atom or deuterium, n is 5
The following positive integer). 3. A flat plastic optical waveguide comprising: a core portion made of a polymer containing deuterium or a halogen atom; and a clad portion surrounding the core portion and made of a polymer having a lower refractive index than the core portion. Wherein the portion is a deuterated or halogenated polysiloxane having a chemical structure represented by the following general formula (II) or (III) as a repeating unit: However, R ₃ and R ₄ are each C _n Y _{2n + 1} (Y is a deuterium or a halogen atom, n is a positive integer of 5 or less) or C ₆
Is a Y _5. 4. A flat plastic optical waveguide comprising: a core portion made of a polymer containing deuterium or a halogen atom; and a clad portion surrounding the core portion and made of a polymer having a lower refractive index than the core portion. Wherein the portion is a deuterium or halogenated polysiloxane of a copolymer comprising two or more different repeating units of the chemical structure represented by the following general formula (II) or (III): Plastic optical waveguide: Here, R ₃ and R ₄ are each C _n Y _{2n + 1} (Y is a deuterium or a halogen atom, n is a positive integer of 5 or less) or C ₆
Is a Y _5. 5. A flat plastic optical waveguide having a core portion made of a polymer containing a deuterium or a halogen atom and a clad portion surrounding the core portion and made of a polymer having a lower refractive index than the core portion. Is the following general formula (II) or (III)
A planar plastic optical waveguide, which is a copolymer of a deuterated or halogenated siloxane having a repeating unit represented by the following chemical structure: Here, R ₃ and R ₄ are each C _n Y _{2n + 1} (Y is a deuterium or a halogen atom, n is a positive integer of 5 or less) or C ₆
Is a Y _5. 6. A flat plastic optical waveguide having a core portion made of a polymer containing deuterium or a halogen atom, and a clad portion surrounding the core portion and made of a polymer having a lower refractive index than the core portion. Wherein the portion is a halogenated or deuterated polystyrene having a chemical structure represented by the following general formula (IV) as a repeating unit: Here, Y is a halogen atom or deuterium. 7. A flat plastic optical waveguide comprising: a core portion made of a polymer containing a deuterium or halogen atom; and a cladding portion surrounding the core portion and made of a polymer having a lower refractive index than the core portion. Wherein the portion is a copolymer deuterium or halogenated polystyrene composed of two or more different repeating units of the chemical structure represented by the following general formula (IV): Here, Y is a halogen atom or deuterium. 8. A flat plastic optical waveguide according to claim 1, wherein said cladding portion is made of a polymer having deuterium or halogen atoms. 9. The flat plastic according to claim 8, wherein said cladding portion is a deuterated or halogenated polyacrylate having a repeating unit of a chemical structure represented by the following general formula (I). Optical waveguide: Here, X ₁ and X ₂ are each deuterium, or halogen atom, R ₁ is deuterated, one of a CD ₃ group, and a halogen atom, R ₂ is halide represented by C _n Y _{2n + 1} or heavy Hydrogenated alkyl group (Y is a halogen atom or deuterium, n is 5
The following positive integer). 10. The method according to claim 1, wherein said cladding portion is a deuterated or halogenated polyacrylate of a copolymer comprising two or more different repeating units in the chemical structure represented by the following general formula (I). The flat plastic optical waveguide according to claim 8, wherein: However, X ₁ and X ₂ are each deuterium, or halogen atom, R ₁ is deuterated, halogenated or deuterated CD ₃ group, and one of a halogen atom, R ₂ is represented by C _n Y _{2n + 1} Alkyl group (Y is a halogen atom or deuterium, n is 5
The following positive integer). 11. The method according to claim 8, wherein the cladding portion is a deuterated or halogenated polysiloxane having a chemical structure represented by the following general formula (II) or (III) as a repeating unit. Flat plastic optical waveguide: Here, R ₃ and R ₄ are each C _n Y _{2n + 1} (Y is a deuterium or a halogen atom, n is a positive integer of 5 or less) or C ₆
Is a Y _5. 12. The clad portion is a copolymer deuterium or halogenated polysiloxane comprising two or more different repeating units of the chemical structure represented by the following general formula (II) or (III). 9. The planar plastic optical waveguide according to claim 8, wherein: Here, R ₃ and R ₄ are each C _n Y _{2n + 1} (Y is a deuterium or a halogen atom, n is a positive integer of 5 or less) or C ₆
Is a Y _5. 13. The clad portion is a deuterated or halogenated polysiloxane copolymer having a chemical structure represented by the following general formulas (II) and (III) as a repeating unit. The plastic optical waveguide according to claim 8, wherein: 14. The flat plastic according to claim 8, wherein the cladding is a halogenated or deuterated polystyrene having a chemical structure represented by the following general formula (IV) as a repeating unit. Optical waveguide: Here, Y is a halogen atom or deuterium. 15. The cladding part is a deuterated or halogenated polystyrene of a copolymer comprising two or more different repeating units of the chemical structure represented by the following general formula (IV). The flat plastic optical waveguide according to claim 8, wherein: Here, Y is a halogen atom or deuterium. 16. A substrate, comprising: a lower clad portion, a core portion, and an upper clad portion surrounding the core portion together with the lower clad portion, each of which is sequentially formed on the substrate, wherein the core portion is deuterium. A polymer or copolymer of a halogenated or halogenated acrylate, a polymer or a copolymer of a deuterated or halogenated siloxane, and one of a polymer or a copolymer of a deuterated or halogenated styrene. Flat plastic optical waveguide. 17. The method according to claim 17, wherein the lower and upper clad portions are formed of a polymer or copolymer of deuterium or a halogenated acrylate, a polymer or copolymer of a deuterated or halogenated siloxane, and a deuterated or halogenated styrene. 17. The flat plastic optical waveguide according to claim 16, wherein the flat plastic optical waveguide is made of one of a united material and a copolymer.