JP2006276735A - Optical waveguide and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an optical waveguide permitting to efficiently manufacture a high performance polymer optical waveguide inexpensively, and to provide an optical waveguide manufactured by the manufacturing method of the optical waveguide. <P>SOLUTION: In the manufacturing method of the optical waveguide, the optical waveguide is formed by giving a refractive index conditioner to a part where the optical waveguide of a polymer base body is arranged, and diffusing the refractive index conditioner into the base body. There are preferred a mode of diffusing the refractive index conditioner into the base body by masking a part to form the optical waveguide thereon except an aperture part and giving the refractive index conditioner to the aperture part, a mode diffusing the refractive index conditioner into the base body by providing the base body surface with a groove part corresponding to a part to form the optical waveguide thereon and giving the refractive index conditioner into the groove part, and the like. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a simple, inexpensive and high performance optical waveguide using a polymer material, and an optical waveguide produced by the method for producing the optical waveguide.

  Conventionally, various methods have been proposed as a method of manufacturing an optical waveguide. For example, quartz is used as a material, and a core and a clad are formed by a method applying RIE etching or photolithography. As a result of using expensive equipment and equipment, the process is expensive.

For this reason, it has been attempted to produce a refractive index distribution type optical waveguide by diffusion of dopant. For example, it has been proposed to form an optical waveguide by diffusing Ti in lithium niobate (LiNbO ₃ , LN) (see, for example, Patent Document 1 and Patent Document 2). According to this dopant diffusion method, an optical waveguide can be manufactured at low cost without an etching process or the like. In addition, since a large-scale apparatus using a vacuum is not required, this is a method suitable for upsizing and mass production, and even a complicated optical waveguide can be formed without any problem. Furthermore, since there is no need to cut or shape the optical waveguide such as etching, the waveguide loss is good.

  However, recently, the use of optical waveguides for folding cellular phones, hinge portions through which signal lines connecting a main body including a keypad or a main board and a liquid crystal panel pass, etc. has been studied. Such an optical waveguide is required to be mechanically flexible and optical characteristics are not deteriorated even if the optical wiring is bent, and the optical waveguide using the inorganic material cannot be used. Waveguides are being studied.

  Therefore, as a method for efficiently and inexpensively manufacturing a film optical waveguide suitable for manufacturing such an optical wiring, for example, a core material is applied to the surface of a clad substrate in which a concave groove serving as an optical waveguide core is formed by a stamper. Or a method of pressing the coated core material from above and crushing it flatly (see Patent Document 3 and Patent Document 4). However, these proposed methods also require a plurality of processes by producing a mold.

  Therefore, at present, there is a demand for prompt provision of a method for producing a polymer optical waveguide capable of efficiently producing a high-performance optical waveguide at a lower cost.

Japanese Patent Laid-Open No. 11-258439 Japanese Patent Laid-Open No. 2004-287093 JP-A-9-281351 Japanese Patent No. 2679760

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, the present invention provides an optical waveguide manufacturing method capable of efficiently manufacturing a high-performance optical waveguide at low cost by a simple method of simply diffusing a refractive index adjusting agent in a polymer substrate, and the optical waveguide An object of the present invention is to provide an optical waveguide manufactured by a manufacturing method.

Means for solving the above problems are as follows. That is,
<1> A method for producing an optical waveguide, comprising: providing a polymer substrate with an optical waveguide at a position where the optical waveguide is provided, and diffusing the refractive index adjuster into the substrate to form the optical waveguide. In the method for producing an optical waveguide according to <1>, a refractive index adjusting agent is applied to a portion of the polymer substrate where the optical waveguide is provided, and the refractive index adjusting agent is diffused in the substrate, so that high performance can be achieved at low cost. A simple optical waveguide can be efficiently manufactured.
<2> The method for producing an optical waveguide according to <1>, in which a portion other than the opening corresponding to the location where the optical waveguide of the polymer base is provided is masked, and a refractive index adjusting agent is applied to the opening. In the method for producing an optical waveguide according to <2>, the refractive index adjusting agent is efficiently diffused in the portion where the optical waveguide is provided by masking portions other than the opening corresponding to the portion where the optical waveguide of the polymer base is provided. Thus, a high-performance optical waveguide can be manufactured.
<3> The method for producing an optical waveguide according to <1>, wherein a groove portion corresponding to a location where the optical waveguide of the polymer substrate is provided is provided on the surface of the substrate, and a refractive index adjusting agent is applied to the groove portion. In the method for producing an optical waveguide according to <3>, by providing a groove portion corresponding to the location where the optical waveguide of the polymer substrate is provided, the refractive index adjusting agent is efficiently diffused in the location where the optical waveguide is provided, A high performance optical waveguide can be manufactured.
<4> A refractive index adjusting agent is applied to a portion where an optical waveguide is provided on at least one of the surfaces of the first polymer substrate and the second polymer substrate, and the first polymer substrate and the second polymer are provided on the surface where the refractive index adjusting agent is applied. A method of manufacturing an optical waveguide, comprising: bonding a polymer substrate and diffusing a refractive index adjusting agent in both substrates to form an optical waveguide. In the method for producing an optical waveguide according to <4>, a high-performance optical waveguide in which the refractive index adjusting agent is diffused substantially concentrically can be formed.
<5> The method for producing an optical waveguide according to any one of <1> to <4>, wherein the application of the refractive index adjusting agent is coating. In the method for producing an optical waveguide according to <5>, the refractive index adjusting agent can be efficiently applied to the polymer substrate by coating.
<6> The optical waveguide manufacturing method according to any one of <1> to <5>, wherein the refractive index adjusting agent is diffused by a heat treatment. In the method for producing an optical waveguide according to <6>, the refractive index adjusting agent can be efficiently diffused into the polymer substrate by heating.
<7> The method for producing an optical waveguide according to any one of <1> to <6>, wherein the polymer substrate includes a polymer having no electronic transition absorption at a use wavelength. In the method for producing an optical waveguide according to <7>, the polymer substrate contains a polymer having no electronic transition absorption at the wavelength used. This electronic transition absorption is absorption due to excitation of electrons such as n-π and π-π, and is remarkably observed in an organic compound containing a benzene ring or a C═O group. If there is this absorption in the communication wavelength band, loss increases, chemical reactions are likely to occur, and the base deteriorates.
<8> The light according to <7>, wherein the polymer is at least one selected from an acrylic resin, a polycarbonate resin, a silicone resin, a polyimide resin, a polyethylene terephthalate (PET) resin, and a norbornene resin. It is a manufacturing method of a waveguide.
<9> The method for producing an optical waveguide according to any one of <1> to <8>, wherein a refractive index of the refractive index adjusting agent is 0.005 or more higher than a refractive index of a polymer constituting the polymer substrate.
<10> The refractive index adjusting agent is benzyl benzoate (BEN), diphenyl sulfide (DPS), triphenyl phosphate (TPP), benzyl-n-butyl phthalate (BBP), diphenyl phthalate (DPP), biphenyl ( DP), diphenylmethane (DPM), tricresyl phosphate (TCP), bromobenzene, and diphenyl sulfoxide (DPSO) are at least one selected from the above <1> to <9> It is a manufacturing method.
<11> The method for producing an optical waveguide according to any one of <1> to <10>, wherein the refractive index adjusting agent includes at least two compounds having different sizes. In the method for producing an optical waveguide according to <11>, the refractive index distribution in the polymer substrate can be adjusted efficiently.
<12> The method for producing an optical waveguide according to any one of <1> to <3> and <5> to <11>, wherein an overcladding layer is provided on the surface of the substrate after the refractive index adjusting agent is diffused. . In the method for producing an optical waveguide according to <12>, by providing an over clad layer on the substrate surface after the refractive index adjusting agent is diffused, the substrate surface is protected, the optical loss is reduced, and the TE / TM mode. Loss can be reduced.
<13> The method for producing an optical waveguide according to <12>, wherein the over clad layer contains the same polymer as the polymer constituting the polymer substrate.
<14> An optical waveguide manufactured by the method for manufacturing an optical waveguide according to any one of <1> to <13>.

  According to the present invention, conventional problems can be solved, and an optical waveguide can be efficiently produced by a simple method in which a refractive index adjusting agent is diffused into a polymer substrate. In addition, the optical waveguide manufacturing method of the present invention has many options for polymers that can diffuse the refractive index adjusting agent into the substrate, and has a high degree of freedom. Furthermore, since it is a refractive index distribution type optical waveguide, it is advantageous in terms of loss compared to a step type optical waveguide, and an inexpensive and high-performance optical waveguide can be provided.

(Optical waveguide and optical waveguide manufacturing method)
In the first embodiment, the optical waveguide manufacturing method of the present invention, in the first embodiment, a refractive index adjusting agent applying step for applying a refractive index adjusting agent to a portion where the optical waveguide of the polymer substrate is provided, and the refractive index adjusting agent is diffused in the substrate. A refractive index adjusting agent diffusing step to be performed, and further including other steps as necessary.
The optical waveguide of the present invention is manufactured by the method for manufacturing an optical waveguide of the present invention.
Hereinafter, the details of the optical waveguide of the present invention will be clarified through the description of the optical waveguide manufacturing method of the present invention.

<Refractive index adjusting agent application step>
In the method for producing an optical waveguide according to the first embodiment, as a method of applying a refractive index adjusting agent to the portion where the optical waveguide of the polymer base is provided, there is no particular limitation and can be appropriately selected according to the purpose. For example, application, spraying, adhesion, immersion, deposition, and the like can be mentioned, and among these, application is particularly preferable.

The coating is not particularly limited and can be appropriately selected depending on the purpose. If the refractive index adjuster is liquid, it is directly applied. If the refractive index adjuster is not liquid, an appropriate solvent is used. It can be applied after dissolving and forming a coating solution.
There is no restriction | limiting in particular as said application | coating method, According to the objective, it can select suitably, Brush coating, a roll coater, a die coater, a curtain coater, etc. are mentioned.

  There is no restriction | limiting in particular as a shape of the location which provides the optical waveguide in the said polymer base | substrate, According to the objective, it can select suitably, In addition to linear form, substantially Y shape, substantially V shape, and substantially X shape And various branched shapes such as a substantially U-shape.

  As the method for applying the refractive index adjusting agent, specifically, (1) a mode of masking other than the opening corresponding to the location where the optical waveguide of the polymer substrate is provided, and applying the refractive index adjusting agent to the opening, (2) The aspect which provides the groove part corresponding to the location where the optical waveguide of a polymer base | substrate is provided in this base | substrate surface, and provides a refractive index regulator to this groove part etc. is mentioned suitably.

In the aspect (1), the method for masking other than the opening corresponding to the location where the optical waveguide of the polymer substrate is provided is not particularly limited and can be appropriately selected according to the purpose. For example, (i) A method of attaching a mask having an opening corresponding to a location where an optical waveguide is provided, to the surface of the substrate; (ii) a method of applying a material that does not allow the refractive index adjusting agent to pass through other than the aperture corresponding to the location where the optical waveguide is provided; ) A method of covering a portion other than the opening corresponding to the location where the optical waveguide is provided with a sealing material that does not pass the refractive index adjusting agent. Among these, the method using the mask (i) is particularly preferable.
The material of the mask is not particularly limited and can be appropriately selected according to the purpose. Examples thereof include a metal mask such as chromium, an emulsion mask, a resist material for a photomask, and the like. There is no restriction | limiting in particular as a providing method, The method normally performed in the said technical field is employable.
In addition, there is no restriction | limiting in particular as the provision method of the refractive index regulator to the opening part of the said mask, According to the objective, it can select suitably, For example, the coating method etc. which were mentioned above are mentioned.

In the aspect of (2), there is no particular limitation on the shape, size, formation method, and the like as long as the groove portion corresponding to the location where the optical waveguide of the polymer base is provided can hold the refractive index adjusting agent, It can be appropriately selected according to the purpose, and examples of the cross-sectional shape of the groove include a quadrangle, a semicircle, and an inverted triangle.
The method for forming the groove is not particularly limited and may be appropriately selected depending on the purpose.For example, a method for forming the groove simultaneously with the molding of the substrate using a mold, a method for cutting the surface of the substrate, Etc.
There is no restriction | limiting in particular as a provision method of the refractive index regulator to the said groove part, According to the objective, it can select suitably, For example, the coating method etc. which were mentioned above are mentioned.

-Polymer substrate-
The shape, structure, size and the like of the polymer substrate are not particularly limited and can be appropriately selected according to the purpose. Examples of the shape include a flat plate shape, a sheet shape, and a film shape. The structure may be a single-layer structure or a laminated structure, and the size may be appropriately selected according to the use or type of the optical waveguide.

  The material for the polymer substrate is not particularly limited, and any material commonly used for optical waveguides can be suitably used, but a polymer having no electronic transition absorption at the wavelength used is suitably used. This electron transition absorption is absorption due to excitation of electrons such as n-π and π-π, and is remarkably observed in an organic compound containing a benzene ring or a C═O group. If there is this absorption in the communication wavelength band, loss increases, chemical reactions are likely to occur, and the base deteriorates.

  Examples of the material for the polymer substrate include (meth) acrylic acid esters (fluorine-free (meth) acrylic acid ester (i), fluorine-containing (meth) acrylic acid ester (ii)), and styrenic compound (iii). , Vinyl esters (iv), those obtained by polymerizing bisphenol A, which is a raw material of polycarbonates, as a polymerizable compound, and polyvinylidene fluoride (PVDF). Examples thereof include homopolymers obtained by polymerizing these as raw materials, copolymers obtained by combining two or more of these, and mixtures of the homopolymers and copolymers.

  Examples of the fluorine-free methacrylic acid ester and the fluorine-free acrylic acid ester (i) include, for example, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, tert-butyl methacrylate, benzyl methacrylate, phenyl methacrylate, Examples include cyclohexyl methacrylate, diphenylmethyl methacrylate, adamantyl methacrylate, isobornyl methacrylate, norbornyl methacrylate and the like. Among these, methyl acrylate, ethyl acrylate, tert-butyl acrylate, phenyl acrylate, and the like are particularly preferable.

  Examples of the fluorine-containing acrylic ester and fluorine-containing methacrylate ester of (ii) include 2,2,2-trifluoroethyl methacrylate, 2,2,3,3-tetrafluoropropyl methacrylate, 2,2,3. , 3,3-pentafluoropropyl methacrylate, 1-trifluoromethyl-2,2,2-trifluoroethyl methacrylate, 2,2,3,3,4,4,5,5-octafluoropentyl methacrylate, 2, 2,3,3,4,4-hexafluorobutyl methacrylate and the like.

Examples of the (iii) styrene compound include styrene, α-methylstyrene, chlorostyrene, bromostyrene, and the like.
Examples of the vinyl ester (iv) include vinyl acetate, vinyl benzoate, vinyl phenyl acetate, and vinyl chloroacetate.

  Moreover, as a polymer which forms the said polymer base | substrate, in addition to said various compounds, for example, methyl methacrylate (MMA) and fluoride (meth) acrylates such as trifluoroethyl methacrylate (FMA) and hexafluoroisopropyl methacrylate are used. Mention may be made of copolymers. In addition, copolymers of MMA and alicyclic (meth) acrylates such as (meth) acrylate having a branch such as tert-butyl methacrylate, isobornyl methacrylate, norbornyl methacrylate, tricyclodecanyl methacrylate, etc. It is done. Furthermore, polycarbonate (PC), norbornene-based resin (for example, ZEONEX (registered trademark: manufactured by Nippon Zeon Co., Ltd.), functional norbornene-based resin (for example, ARTON (registered trademark: manufactured by JSR)), fluorine resin (for example, , Polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), etc.) Also, a fluororesin copolymer (for example, PVDF copolymer), tetrafluoroethylene perfluoro (alkyl vinyl ether), etc. (PFA)) Random copolymer, chlorotrifluoroethylene (CTFE) copolymer, etc. can also be used, and the hydrogen loss (H) of these polymers is replaced with deuterium atoms (D), resulting in transmission loss. Can also be reduced.

  Other additives can be added to the polymer substrate as long as the optical transmission performance is not deteriorated. For example, a stabilizer can be added for the purpose of improving weather resistance and durability. Further, for the purpose of improving optical transmission performance, a stimulated emission functional compound for optical signal amplification can be added.

-Refractive index modifier (dopant)-
The refractive index adjusting agent is preferably a compound having good compatibility with the polymer in the polymer substrate and having a refractive index higher by 0.005 or more than the refractive index of the polymer constituting the polymer substrate. The refractive index difference is preferably 0.005 or more, and more preferably 0.01 or more. When the difference in refractive index is less than 0.005, the numerical aperture (NA) becomes small, the confinement effect becomes small, and light may easily leak.

  Examples of the refractive index adjusting agent include benzyl benzoate (BEN), diphenyl sulfide (DPS), triphenyl phosphate (TPP), benzyl n-butyl phthalate (BBP), diphenyl phthalate (DPP), and biphenyl. (DP), diphenylmethane (DPM), tricresyl phosphate (TCP), bromobenzene, diphenyl sulfoxide (DPSO), and the like. Among these, BEN, DPS, TPP, and DPSO are preferable, and when a PMMA base is used, DPS and DPSO are particularly preferable.

  As the refractive index adjusting agent, it is preferable to use at least two kinds of compounds having different sizes from the viewpoint that the refractive index distribution in the polymer substrate at the time of diffusion can be efficiently formed.

The amount of the refractive index adjusting agent applied varies depending on the polymer material of the polymer substrate, the size and shape of the optical waveguide to be formed, and cannot be specified unconditionally. For example, 0.01 to 10 g / cm ² is preferable.

<Refractive index modifier diffusion process>
The refractive index adjusting agent diffusing step is a step of diffusing the refractive index adjusting agent in the polymer substrate to form an optical waveguide.
The diffusion method is not particularly limited and can be appropriately selected depending on the purpose.For example, the diffusion method can be diffused simply by applying a refractive index adjusting agent and leaving it as it is. It is preferable to heat-process from the point which raises.

When the refractive index adjusting agent is diffused into the substrate, it is preferable to perform a heat treatment.
There is no restriction | limiting in particular as said heat processing, According to the objective, it can select suitably, It is preferable to carry out on conditions of 100 degreeC or more and 1 hour or more, and to carry out on conditions of 120 degreeC or more and 10 hours or more. More preferred.

In the first embodiment, it is preferable to provide an overcladding layer on the surface of the substrate after the refractive index adjusting agent is diffused from the viewpoint of protecting the substrate surface, reducing optical loss, and reducing TE / TM mode loss. .
As the overcladding layer, it is preferable to use the same polymer as that constituting the polymer substrate.
There is no restriction | limiting in particular in formation of the said over clad layer, According to the objective, it can select suitably, For example, the apply | coating method etc. are mentioned.
There is no restriction | limiting in particular in the thickness of the said over clad layer, According to the objective, it can select suitably, 1-1000 micrometers is preferable.

Here, an example of the manufacturing method of the optical waveguide which concerns on the 1st form of this invention is demonstrated with reference to drawings.
FIG. 1A to FIG. 1D are manufacturing process diagrams showing an example of a method for manufacturing an optical waveguide that masks the portion other than the opening corresponding to the location where the optical waveguide of the polymer base of the present invention is provided.
First, as shown in FIG. 1A, a mask 2 having an opening 3 corresponding to a location where an optical waveguide is provided is disposed on a polymer substrate 1.
Next, as shown in FIG. 1B, a predetermined amount of refractive index adjusting agent 4 is applied to the opening 3 of the mask. In this example, it is given by application.
Next, as shown in FIG. 1C, the polymer substrate 1 provided with the refractive index adjusting agent is heated to diffuse the refractive index adjusting agent into the substrate.
Next, as shown in FIG. 1D, after the diffusion of the refractive index adjusting agent is completed, the mask is peeled off, and the surface of the substrate 1 is covered with the over clad layer 5.
Thus, an optical waveguide can be manufactured.

2A to 2D are manufacturing process diagrams illustrating an example of a method of manufacturing an optical waveguide according to the present invention in which a groove portion corresponding to a portion where an optical waveguide of a polymer base is provided is provided and a refractive index adjusting agent is applied to the groove portion. It is.
First, as shown in FIG. 2A, a polymer substrate 1 provided with a groove 6 corresponding to a location where an optical waveguide was provided was prepared. In this example, a polymer substrate having a groove was produced by injection molding.
Next, as shown in FIG. 2B, a predetermined amount of the refractive index adjusting agent 4 is applied to the groove 6. In this example, it is given by application.
Next, as shown in FIG. 2C, the polymer substrate 1 provided with the refractive index adjusting agent is heated to diffuse the refractive index adjusting agent into the substrate.
Next, as shown in FIG. 2D, after the diffusion is completed, the overcladding layer 5 is coated on the substrate surface including the groove.
Thus, an optical waveguide can be manufactured.

<Method for Manufacturing Optical Waveguide of Second Form>
In the second embodiment, the method for producing an optical waveguide according to the present invention includes a step of applying a refractive index adjusting agent to a portion where the optical waveguide on the surface of at least one of the first polymer substrate and the second polymer substrate is provided, and the refraction. A step of bonding the first polymer substrate and the second polymer substrate on the surface to which the rate adjusting agent is applied, and diffusing the refractive index adjusting agent in both substrates, and further including other steps as necessary. Become. According to the second embodiment, a concentric optical waveguide can be efficiently formed by a simple method.

The first polymer substrate and the second polymer substrate preferably have the same shape formed by using the same polymer material.
There is no restriction | limiting in particular as the provision method of the said refractive index adjuster, According to the objective, it can select suitably, The application method similar to the said 1st form can be employ | adopted, and application | coating by application | coating is especially preferable.
Further, after applying a refractive index adjusting agent to the surfaces of the first and second substrates corresponding to the locations where the optical waveguides of the polymer substrate are formed, and letting it stand at room temperature for a while, the first substrate and the second substrate are bonded to each other on the coated surface. It is preferable to make it.
Examples of the bonding method between the first polymer substrate and the second polymer substrate include a method of attaching using an adhesive, a screwing method, thermal adhesion, a method of engaging lock members, and the like. It is done.

Here, FIG. 3 is a manufacturing process diagram showing an example of a manufacturing method of the optical waveguide according to the second embodiment of the present invention.
First, the first polymer substrate 10 and the second polymer substrate 11 are prepared, and the refractive index adjusting agent 4 is applied by coating on the surface of the polymer substrate where the optical waveguide is provided, and left at room temperature for a predetermined time.
Next, the first substrate and the second substrate are bonded to each other on the application surface and heated to diffuse the refractive index adjusting agent in both substrates.
Thus, an optical waveguide can be manufactured.

  The optical waveguide manufactured by the optical waveguide manufacturing method of the present invention can be widely applied as an optical waveguide component such as an inexpensive, low-loss optical interconnection, optical demultiplexer, or multiplexer in the field of optical fiber communication.

  Examples of the present invention will be described below, but the present invention is not limited to the following examples.

Example 1
A refractive index distribution type optical waveguide was manufactured by the method for manufacturing an optical waveguide of the present invention shown in FIGS. 1A to 1D.
That is, a metal mask having an opening corresponding to a position where an optical waveguide was provided was attached on an optical grade acrylic resin plate (PMMA, width 10 mm, thickness 3 mm, length 50 mm, refractive index = 1.49). 0.5 g of diphenyl sulfide (DPS, refractive index = 1.63) was poured into the opening of this mask and kept at 120 ° C. for 100 hours.
Next, after producing the optical waveguide, the mask was peeled off, and an over clad layer (PMMA) having a thickness of 500 μm was formed on the entire surface of the acrylic resin plate. Thus, a refractive index distribution type optical waveguide was produced.

<Evaluation>
The obtained optical waveguide was measured for optical transmission loss at a wavelength of 850 nm using a surface emitting semiconductor laser (VCSEL) as a light source, and found to be 0.10 dB / cm.

(Example 2)
A refractive index distribution type optical waveguide was manufactured by the method for manufacturing an optical waveguide of the present invention shown in FIGS. 1A to 1D.
On the optical grade heat-resistant acrylic plate (isobonyl methacrylate (IBXMA), width 10 mm, thickness 3 mm, length 50 mm, refractive index = 1.500), a Y-branch opening corresponding to the location where the optical waveguide is provided A resist mask having was attached. 0.4 g of diphenyl sulfoxide (DPSO, refractive index = 1.61) was poured into the opening of the mask and maintained at 140 ° C. for 50 hours.
Next, after producing the optical waveguide, the mask was peeled off, and an over clad layer (PMMA) having a thickness of 1000 μm was formed on the entire surface of the acrylic resin plate. Thus, a refractive index distribution type optical waveguide was produced.

<Evaluation>
The obtained optical waveguide was measured for optical transmission loss at a wavelength of 850 nm using a surface emitting semiconductor laser (VCSEL) as a light source, and was found to be 0.15 dB / cm.

(Example 3)
A refractive index distribution type optical waveguide was manufactured by the method for manufacturing an optical waveguide of the present invention shown in FIGS. 1A to 1D.
Emulsion mask having an opening by design of a directional coupler corresponding to a location where an optical waveguide is provided on a BnMA / PMMA copolymer acrylic plate (width 10 mm, thickness 3 mm, length 50 mm, refractive index = 1.51) Attached. 1 g of bromobenzene (refractive index = 1.56) was poured into the opening of this mask and kept at 120 ° C. for 100 hours.
Next, after producing the optical waveguide, the mask was peeled off, and an over clad layer (PMMA) having a thickness of 1000 μm was formed on the entire surface of the acrylic resin plate. The directional coupler was produced by the above.

<Evaluation>
The obtained optical waveguide was measured for optical transmission loss at a wavelength of 850 nm using a surface emitting semiconductor laser (VCSEL) as a light source, and found to be 0.18 dB / cm.

Example 4
A refractive index distribution type optical waveguide was manufactured by the method for manufacturing an optical waveguide of the present invention shown in FIGS. 2A to 2D.
That is, an optical grade acrylic resin plate (PMMA, width 10 mm, thickness 3 mm, length 50 mm, refractive index = 1.49) having a groove corresponding to the location where the optical waveguide is provided was prepared. 0.5 g of diphenyl sulfide (DPS, refractive index = 1.63) was poured into the groove and kept at 120 ° C. for 100 hours.
Next, an over clad layer having a thickness of 100 μm was formed by thermal polymerization on the surface of the substrate including the groove by applying PMMA syrup. Thus, a refractive index distribution type optical waveguide was produced.

<Evaluation>
The obtained optical waveguide was measured for optical transmission loss at a wavelength of 850 nm using a surface emitting semiconductor laser (VCSEL) as a light source, and found to be 0.23 dB / cm.

(Example 5)
A refractive index distribution type optical waveguide was manufactured by the method for manufacturing an optical waveguide of the present invention shown in FIG.
That is, two optical grade acrylic resin plates (PMMA, width 10 mm, thickness 3 mm, length 50 mm, refractive index = 1.49) were prepared. On each acrylic resin plate, 0.5 g of diphenyl sulfide (DPS, refractive index = 1.63) was applied to the location corresponding to the location where the optical waveguide was provided, and left at room temperature for 24 hours.
Next, the first substrate and the second substrate were bonded to each other on the coated surface, and heated at 120 ° C. for 100 hours to diffuse the refractive index adjuster in both substrates.
Thus, a refractive index distribution type optical waveguide was produced.

  An optical waveguide manufactured by the optical waveguide manufacturing method of the present invention and an optical waveguide manufactured by the optical waveguide manufacturing method is used as an optical waveguide component such as an inexpensive, low-loss optical interconnection, optical demultiplexer, or multiplexer in the optical fiber communication field. Widely applicable.

FIG. 1A is an explanatory diagram for explaining an example of a method of manufacturing an optical waveguide according to the first embodiment of the present invention, and shows a state in which a mask is disposed on a substrate. FIG. 1B is an explanatory diagram for explaining an example of the manufacturing method of the optical waveguide according to the first embodiment of the present invention, and shows a state in which a refractive index adjusting agent is applied to the opening of the mask. FIG. 1C is an explanatory diagram for explaining an example of the manufacturing method of the optical waveguide according to the first embodiment of the present invention, and shows a state where a refractive index adjusting agent is diffused. FIG. 1D is an explanatory diagram for explaining an example of a method of manufacturing an optical waveguide according to the first embodiment of the present invention, and shows a state in which an over clad layer is provided. FIG. 2A is an explanatory diagram for explaining another example of the optical waveguide manufacturing method according to the first embodiment of the present invention, and shows a base body having a groove. FIG. 2B is an explanatory diagram for explaining another example of the method of manufacturing an optical waveguide according to the first embodiment of the present invention, and shows a state where a refractive index adjusting agent is applied to the groove. FIG. 2C is an explanatory diagram for explaining another example of the method of manufacturing an optical waveguide according to the first embodiment of the present invention, and shows a state where a refractive index adjusting agent is diffused. FIG. 2D is an explanatory diagram for explaining another example of the method of manufacturing the optical waveguide according to the first embodiment of the present invention, and shows a state in which an over clad layer is provided. FIG. 3 is an explanatory diagram for explaining an example of a method of manufacturing an optical waveguide according to the second embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Polymer base | substrate 2 Mask 3 Mask opening part 4 Refractive index regulator 5 Over clad layer 6 Groove part 10 1st polymer base | substrate 11 2nd polymer base | substrate

Claims (14)

  A method for producing an optical waveguide, comprising: applying a refractive index adjusting agent to a portion of the polymer substrate where the optical waveguide is provided, and diffusing the refractive index adjusting agent in the substrate to form the optical waveguide.   The manufacturing method of the optical waveguide of Claim 1 which masks other than the opening part corresponding to the location which provides the optical waveguide of a polymer base | substrate, and provides a refractive index adjusting agent to this opening part.   The method for producing an optical waveguide according to claim 1, wherein a groove portion corresponding to a location where the optical waveguide of the polymer substrate is provided is provided on the surface of the substrate, and a refractive index adjusting agent is applied to the groove portion.   A refractive index adjusting agent is applied to a portion where an optical waveguide is formed on at least one surface of the first polymer substrate and the second polymer substrate, and the first polymer substrate and the second polymer substrate are provided on the surface where the refractive index adjusting agent is applied. And an optical waveguide is formed by diffusing a refractive index adjusting agent in both substrates to form an optical waveguide.   The method for producing an optical waveguide according to claim 1, wherein the application of the refractive index adjusting agent is coating.   The method for manufacturing an optical waveguide according to claim 1, wherein the diffusion of the refractive index adjusting agent is performed by heat treatment.   The method for producing an optical waveguide according to claim 1, wherein the polymer substrate contains a polymer having no electronic transition absorption at the wavelength used.   8. The method for producing an optical waveguide according to claim 7, wherein the polymer is at least one selected from an acrylic resin, a polycarbonate resin, a silicone resin, a polyimide resin, a polyethylene terephthalate (PET) resin, and a norbornene resin. .   The method for producing an optical waveguide according to claim 1, wherein the refractive index of the refractive index adjusting agent is 0.005 or more higher than the refractive index of the polymer constituting the polymer substrate.   Refractive index modifiers are benzyl benzoate (BEN), diphenyl sulfide (DPS), triphenyl phosphate (TPP), benzyl-n-butyl phthalate (BBP), diphenyl phthalate (DPP), biphenyl (DP), The method for producing an optical waveguide according to claim 1, wherein the optical waveguide is at least one selected from diphenylmethane (DPM), tricresyl phosphate (TCP), bromobenzene, and diphenyl sulfoxide (DPSO).   The method for producing an optical waveguide according to claim 1, wherein the refractive index adjusting agent contains at least two compounds having different sizes.   12. The method of manufacturing an optical waveguide according to claim 1, wherein an over clad layer is provided on the surface of the substrate after the refractive index adjusting agent is diffused.   The method for manufacturing an optical waveguide according to claim 12, wherein the overcladding layer contains the same polymer as the polymer constituting the polymer substrate. An optical waveguide manufactured by the method for manufacturing an optical waveguide according to claim 1.

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