JP2002286953A - Light guide device and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light guide device which satisfies both a lowered cost and enhanced performance by using a polymerizable mixture of this invention. SOLUTION: The light guide device has a light guide comprising a core and a clad having a lower refractive index than the core. A polymer obtained by curing the polymerizable mixture containing at least a reactive oligomer of formula (a) [where (n) is 0 or an integer of 1-10] and a thermo- or photopolymerization initiator is used for at least one of the core and the clad.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an optical waveguide,
In particular, an optical waveguide element that can be used for various optical integrated circuits or optical wiring boards used in the field of general optics or micro optics, or in the field of optical communication or optical information processing, and a method of manufacturing the optical waveguide element About.

[0002]

2. Description of the Related Art Optical waveguide devices used in the field of optical information processing and optical communication have been actively studied and studied in recent years with the aim of integration, miniaturization, high functionality, and low cost. Actually, quartz-based optical waveguide devices have been put to practical use in a part of the optical communication field. In addition, research on polymer waveguides using inexpensive materials and selecting a simple manufacturing method has been actively conducted.

A method of manufacturing an optical waveguide made of a polymer material includes a photo-locking method or a photo-locking method in which a monomer is included in a polymer material and the monomer is reacted by light irradiation to provide a difference in refractive index from a non-irradiated portion. Photopolymerization method (Kurokawa et al.,
Applied Optics, 17, 646, 1978
), Application of methods used in semiconductor processing such as lithography and etching (Imamura et al., Electronics Letter, Vol. 27, pp. 1342, 1991), method using polymerizable polymer or resist (Trewela et al., SPI)
E, 1177, 379, 1989). In particular, a method for manufacturing a waveguide by forming a core ridge by using a polymerizable polymer is simple and suitable for cost reduction. However, the waveguide obtained by this method has (1) high absorption loss due to insufficient transparency of the polymerizable polymer, and (2) non-uniform shape of the core ridge to be produced, and reproducibility. In addition, there are problems such as high scattering loss and the like, and an optical waveguide device having the same performance as a silica-based optical waveguide device has not been manufactured.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above situation, and has as its object to realize an optical waveguide device which satisfies both low cost and high performance by using a polymer material. Sometimes. Another object of the present invention is to provide a method for manufacturing such an optical waveguide device.

[0005]

The above object is achieved by the present invention described below.

A first aspect of the present invention is an optical waveguide device having a waveguide comprising a core and a clad having a lower refractive index than the core, comprising at least a reactive oligomer represented by the following structural formula (a): An optical waveguide element, characterized in that a polymer obtained by curing a polymerizable mixture containing a heat and a photopolymerization initiator is used for at least one of the core and the clad.

[0007]

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Wherein n is 0 or an integer from 1 to 10. ]

In the optical waveguide device according to the first invention, the polymerizable mixture further includes an oligomer or a prepolymer having at least one carbon-carbon double bond in a molecule.

A second aspect of the present invention is a method for manufacturing an optical waveguide device having a waveguide comprising a core and a clad having a lower refractive index than the core. (1) At least the following structural formula (a) Applying a first polymerizable mixture containing a reactive oligomer represented and a heat or photopolymerization initiator to a substrate,
Curing to form a lower cladding layer,

[0011]

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Wherein n is 0 or an integer from 1 to 10. ]

(2) A second polymerizable mixture containing at least the reactive oligomer represented by the structural formula (a) and a heat or photopolymerization initiator is applied on the lower clad layer, Curing the polymerizable mixture in a pattern to form the core, (3) a third method comprising at least a reactive oligomer represented by the structural formula (a) and a heat or photopolymerization initiator. Applying the polymerizable mixture onto the lower cladding layer and the core and curing the mixture to form an upper cladding layer.

[0014] In the second invention, the step (2) comprises the step of preparing a second polymerizable mixture containing at least the reactive oligomer represented by the structural formula (a) and a heat or photopolymerization initiator. The method is characterized in that it is a step of coating the lower clad layer and irradiating light through a mask to cure the second polymerizable mixture in a pattern to obtain the core. In the step (2), (4) a second polymerizable mixture containing at least a reactive oligomer represented by the structural formula (a) and a heat or photopolymerization initiator is added to the lower cladding layer. (5) curing the second polymerizable mixture applied on the lower clad layer by light irradiation, and (6) forming a resist film on the cured second polymerizable mixture. Forming and patterning the resist film; and (7) etching the cured second polymerizable mixture in a pattern using the patterned resist film as a mask to obtain the core. May be.

Further, in the second invention, at least one of the first polymerizable mixture, the second polymerizable mixture, and the third polymerizable mixture has at least a carbon-carbon double bond in a molecule. It further comprises an oligomer or prepolymer having one. In addition, in the second invention, the third polymerizable mixture may be the same polymerizable mixture as the first polymerizable mixture.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

In the first aspect of the present invention, at least one of a core and a clad is prepared by curing a polymer obtained by curing a polymerizable mixture containing at least a reactive oligomer represented by the following structural formula (a) and a heat or photopolymerization initiator. This is the optical waveguide device used for the above.

[0018]

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Wherein n is 0 or an integer from 1 to 10. ]

The optical waveguide device of the present invention has a core and a clad having a lower refractive index than the core, and a polymerizable mixture containing the reactive oligomer of the structural formula (a) in at least one of the core and the clad. Use Specifically, as an example of the optical waveguide element of the present invention, a clad (10, 10) is formed on a substrate (11) as shown in a schematic sectional view in FIG.
16) having a core (17) inside. In the present invention, the polymerizable mixture is used for at least one of the clad (10, 16) and the core (17) of such a device. As described above, in the present invention, it is possible to use the polymerizable mixture for at least one of the clad (10, 16) and the core (17) and not to use the polymerizable mixture for the other.

In the present invention, it is preferable to use the polymerizable mixture for both the clad and the core.

The substrate used in the optical waveguide device of the present invention is not particularly limited as long as it can withstand the curing of the polymerizable mixture used in the present invention. For example, examples of the substrate include a silicon wafer, a metal plate such as aluminum, stainless steel or steel, a resin substrate such as polyimide, a glass substrate, and a ceramic substrate. Among these, a silicon wafer is preferable in consideration of the surface smoothness, low cost, and the like.

The optical waveguide device of the present invention may be in any of a multimode and a single mode. Further, the optical waveguide device of the present invention can be used for various optical integrated circuits or optical wiring boards used in the field of general optics or micro optics, or in the field of optical communication or optical information processing. Therefore, it can take various shapes and forms according to the purpose of use. Therefore, the size of the optical waveguide device of the present invention changes variously depending on the purpose of use.
For example, in an optical waveguide device used in the field of micro optics,
Width and thickness from 5 to 100 μm, length from 1 cm to 1
It can be 0 cm. Further, the shapes and sizes of the core and the clad can be variously selected according to the purpose of use.

The optical waveguide device of the present invention can be manufactured by a manufacturing method described later. At this time, the clad can be formed from a lower clad layer and an upper clad layer. Specifically, for example, as shown in FIG. 1E, the cladding of the optical waveguide device of the present invention is formed by a lower cladding layer (10).
And an upper cladding layer (16). In this case, it is preferable to use the same polymerizable mixture for the upper clad layer and the lower clad layer. However, as long as the upper clad layer and the lower clad layer have a desired refractive index, it is necessary to use the same polymerizable mixture. There is no.

In the present invention, it is not always necessary to provide a substrate for the optical waveguide device.

Next, a polymerizable mixture for use in the optical waveguide device of the present invention will be described.

The polymerizable mixture of the present invention contains at least the reactive oligomer represented by the structural formula (a) and a heat or photopolymerization initiator (hereinafter also referred to as a curing agent). Therefore, in the present specification, "polymerizable mixture"
It refers to a polymerizable mixture containing at least the reactive oligomer represented by the structural formula (a) and a heat or photopolymerization initiator.

In the present invention, the term "alkyl group containing C _n -C _m carbon atoms" refers to a straight-chain or branched-chain alkyl group containing n to m carbon atoms (n and m are natural numbers). Group or alicyclic aliphatic alkyl group. For example, a C ₁ -C ₁₂ alkyl group refers to a C ₁ -C ₁₂ alkyl group.
To 12 linear or branched alkyl groups and alicyclic aliphatic alkyl groups. Specifically, for example, methyl, ethyl, n-propyl, cyclopropyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl , Dodecyl, etc.

In the present invention, the curing agent has the structural formula (a)
Any substance can be used as long as the reactive oligomer can be polymerized. For example, polyamines, polyols,
Curing agents for epoxy resins, such as acid anhydrides, can be used.

Specifically, as examples of amines, diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEP)
A), dipropylenetriamine (DPTA), bis (hexamethylene) triamine, 1,3,6-trisaminomethylcyclohexane (TMD) polyether polyamines, diethyleneaminopropylamine (DEAP)
A), menthanediamine (MDA), isophoronediamine (IPD), bis (4-amino-3-methylcyclohexyl) methane, N-aminoethylpiperazine (AE)
P), metaxylenediamine (MXDA), metaphenylenediamine (MPDA), diaminodiphenylmethane (DDM), diaminodiphenylsulfone (DDS),
3,9-bis (5-aminopropyl) -2,4,6,1
Examples thereof include 0-tetraspiro [5,5] undecane (ATU) and diaminoethylated polyamines.

In addition to the above, for example, polyamidoamines mainly formed by condensation of dimers and polyamines can also be used. Examples of polyamidoamines include “Tomid” (trade name, manufactured by Fuji Chemical Industry Co., Ltd.),
Trade name "Persamide" (manufactured by Henkel Hakusui Co., Ltd.), trade name "Lacamide" (Dainippon Ink Chemical Industry Co., Ltd.)
Product name) "Polymide" (Sanyo Chemical Industry Co., Ltd.)
Product name), trade name "Sunmide" (Sanwa Chemical Industry Co., Ltd.)
Manufactured).

Specific examples of the polyol include, for example, phenol novolak, o-cresol novolak, polyvinyl phenol, and bromides thereof, 2,2-bis (4'-oxyphenyl) propane, 2,2-bis (4 ' -Oxyphenyl) perfluoropropane and the like.

Examples of the acid anhydrides include phthalic acid, trimellitic acid, pyromellitic acid, benzophenonetetracarboxylic acid anhydrides, maleic acid, succinic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid anhydrides,
Methylnadic acid, dodecenyl succinic acid, hexahydrophthalic acid, methylhexahydrophthalic acid, each anhydride of methylcyclohexenetetracarboxylic acid, chlorendic acid,
Each anhydride of tetrabromophthalic acid can be mentioned.

As a curing agent other than the above, a thermosetting catalyst can be used. In these examples, thermosetting catalysts conventionally used for epoxy resins, such as imidazoles and Lewis acids, can be used.

Examples of imidazoles include 2-methylimidazole (2MZ), 2-ethyl-4-methylimidazole (2E4MZ), 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole (2PZ), 1-benzyl-2-methylimidazole (1B2MZ), 1-cyanoethyl-2-methylimidazole (2MZCM), 1-cyanoethyl-2-
Ethyl-4-methylimidazole (2E4MZ · C
N), 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate (2PZ · CNS),
-Methylimidazolium isocyanurate, 2-phenylimidazolium isocyanurate, 2,4-diamino-6- [2-methylimidazolium (l)]-ethyl-8-triazine (2MZ-22INE), 2,4
-Diamino-6- [2-ethyl-4-methylimidazolium- (l)]-ethyl-8-triazine (2E4MZ
-AZINE), 2-phenyl-4,5-dihydroxymethylimidazole (2PHZ) and the like.

Examples of Lewis acids include boron trifluoride (BF ₃ ), zinc chloride (ZnCl ₂ ), tin tetrachloride (S
nCl ₄ ), aluminum chloride (AlCl ₃ ), phosphorus pentafluoride (PF ₅ ), arsenic pentafluoride (AsF ₅ ), antimony pentafluoride (SbF ₅ ), and the like.
These are commonly used as amine complexes.

In the present invention, a photo-curing catalyst can be used as a curing agent. Examples of the photocuring catalyst include diazonium salts, sulfonium salts, iodonium salts,
A known compound such as a selenium salt which is known to be effective as a curing agent for an epoxy resin can be arbitrarily selected and used.

The diazonium salt can be represented by the following general formula (A). Ar—N ₃ ⁺ X ⁻ (A) wherein Ar is ortho, meta, para nitrophenyl, methoxyphenyl, 2,5-dichlorophenyl, p
-(N-morpholino) phenyl, 2,5-diethoxy-
Represents a group such as 4- (p-trimercapto) phenyl.
X ⁻ represents an anion, for example, BF ₄ ⁻ , FeCl
^{_{4 -, PF 6 -, SbF}} 6 - represents the like. ]

Examples of the sulfonium salt include, for example, bis [4- (diphenylsulfonyl) phenyl] sulfide-bis-hexafluorophosphate, bis- [4-
(Diphenylsulfonyl) phenyl] sulfide-bis-hexafluoroantimonate. In addition to these, 1 of JP-B-59-42688
The compounds described on page 5, line 24 to page 18, line 1 can be used.

Examples of iodonium salts include di- (4-
tert-butylphenyl) iodonium hexafluorophosphate, di- (4-tert-butylphenyl) iodonium hexafluoroantimonate, and the like. In addition, for example, Japanese Patent Publication No. 59-4
No. 2,688, page 11, line 28 to page 12, line 5
The compounds described on line 0 can be used.

Examples of selenium salts include, for example, triphenylselenium hexafluoroantimonate,
Tert-butylphenyldiphenylselenium tetrafluoroborate, 2,3-dimethylphenyldiphenylselenium hexafluoroantimonate and the like can be mentioned.

The polymerizable mixture contains, in addition to the reactive oligomer represented by the structural formula (a) and the curing agent, an oligomer or a prepolymer having at least one carbon-carbon double bond in the molecule. You may.

Examples of such oligomers or prepolymers include the following.

(I) ethylenic polyesters obtained by condensation oligomerization of a polybasic carboxylic acid, a polyhydric alcohol and an ethylenically unsaturated monocarboxylic acid, and (ii) an ethylenically unsaturated monocarboxylic acid Compounds obtained by adding an acid, (ii)
i) ethylenically unsaturated monocarboxylic acid esters of polyether polyol, (iv) ethylenically unsaturated polyurethanes obtained by adding a hydroxyalkyl ester of ethylenically unsaturated monocarboxylic acid to a polyvalent isocyanate compound, ) Diallyl phthalate prepolymer,
(Vi) diallyl isophthalate prepolymer, (vi
i) diallyl isoterephthalate prepolymer.

Specifically, for example, as the ethylenic polyesters of the above (i), oligoesters (meth) obtained by condensation oligomerization with maleic anhydride, propylene glycol and (meth) acrylic acid
Acrylates are mentioned. Further, specific examples of (ii) include epoxy (meth) acrylate obtained by adding (meth) acrylic acid to bisphenol A diglycidyl ether and epoxy (meth) acrylate obtained by adding (meth) acrylic acid to hydrogenated bisphenol A epoxide. And the like. Specific examples of (iii) include polyethylene glycol di (meth) acrylate and polytetraethylene glycol di (meth) acrylate. Specific examples of (iv) include urethane (meth) obtained by reacting a polyurethane having isocyanate groups at both ends obtained by reacting excess isocyanate with ethylene glycol and 2-hydroxyethyl (meth) acrylate. Acrylate and the like can be mentioned.

The polymerizable mixture used in the present invention further includes, for example, various acrylate resins such as conventional epoxy resins, epoxy (meth) acrylate resins, urethane acrylate resins, urethane acrylates, butadiene acrylates, and modified products thereof. You may go out.

Further, as other components, a diluent, a coupling agent and the like may be contained.

The diluents usable in the present invention include alkyl monoglycidyl ethers having 2 to 25 carbon atoms, such as butyl glycidyl ether and 2-ethylhexyl glycidyl ether, butanediol diglycidyl ether,
1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, dodecanediol diglycidyl ether, pentaethitolitol polyglycidyl ether, trimethylolpropane polyglycidyl ether, glycerol polyglycidyl ether, phenyl glycidyl ether, resorcing ricidyl ether P-tert-butylphenyl glycidyl ether, allyl glycidyl ether, tetrafluoropropyl glycidyl ether, octafluoropropyl glycidyl ether, dodecafluoropentyl glycidyl ether, styrene oxide, limonene diepoxide, limonene monoxide, α-pinene epoxide, β
-Pinene epoxide, cyclohexene epoxide, cyclooctene epoxide, vinylcyclohexene oxide and the like. Further, in the present invention, a compound having the following structure can be used as a diluent.

[0049]

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[Wherein Q is H, Cl, Br, C ₁ -C
₁₂ represents an alkyl group or a fluoroalkyl group. ]

[0051]

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As the coupling agent usable in the present invention, an epoxy coupling agent can be used. For example, γ-mercaptopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane,
Examples thereof include a carbon functional silane coupling agent such as β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane.

In the polymerizable mixture of the present invention, the content of the structural formula (a) is 9 to 99.9% by weight, preferably 50 to 99%, based on the weight of the polymerizable mixture.
And the content of the curing agent is 0.1 to 1 wt%.
The content of the oligomer or prepolymer is from 0 to 90% by weight based on the weight of the polymerizable mixture. The diluent and the coupling agent may be added as needed, and may be included in an amount of, for example, 0.1 to 10 wt% based on the weight of the polymerizable mixture.

The contents of the various components in the polymerizable mixture differ depending on whether the polymerizable mixture containing the reactive oligomer of the above structural formula (a) is used for a core or a clad. When a polymerizable mixture containing the reactive oligomer of the structural formula (a) is used for both the core and the clad, the content of each component is adjusted so as to satisfy the desired refractive index relationship between the core and the clad. Need to adjust. Therefore, the above contents are merely examples, and it is apparent to those skilled in the art that the contents of the respective components of the polymerizable mixture that can be used in the present invention can be freely selected according to the purpose of use.

The polymerizable mixture used in the present invention can be prepared by uniformly mixing the above components as required. For example, a curing agent is added to the reactive oligomer represented by the structural formula (a). If necessary,
A polymerizable mixture can be prepared by mixing an oligomer or a prepolymer having at least one carbon-carbon double bond, adding a diluent, a coupling agent, and the like, and uniformly mixing the mixture. Mixing can be performed using a conventional mixing device such as a magnetic stirrer or a mechanical stirrer.

The polymerizable mixture used in the present invention is a liquid. Therefore, it has excellent properties such as processability and storage property.

Next, the second invention will be described. According to a second aspect of the invention, (1) a first polymerizable mixture containing at least a reactive oligomer represented by the following structural formula (a) and a heat or photopolymerization initiator is applied to a substrate and cured. Forming a lower cladding layer,

[0058]

Embedded image

Wherein n is 0 or an integer from 1 to 10. ]

(2) A second polymerizable mixture containing at least the reactive oligomer represented by the structural formula (a) and a heat or photopolymerization initiator is applied on the lower clad layer, Curing the polymerizable mixture in a pattern to form the core, (3) a third method comprising at least a reactive oligomer represented by the structural formula (a) and a heat or photopolymerization initiator. Applying the polymerizable mixture to the lower clad layer and the core and curing the mixture to form an upper clad layer.

The method of the present invention is characterized in that the above polymerizable mixture is used.

The present inventors have found that the above-mentioned polymerizable mixture can form a pattern according to the method of the present invention, and have extremely excellent pattern-forming ability as compared with conventional polymerizable substances. And found that the present invention was completed.

Hereinafter, the method of the present invention will be described. (1) The first step of the production method of the present invention is a step of applying the polymerizable compound to a substrate and curing the substrate. This step forms a lower clat layer on the substrate. Specifically, first, a first polymerizable mixture is prepared and applied to a substrate by a known coating method such as a spin coating method, a dipping method, and an injection method. Next, the polymerizable mixture is cured by applying a treatment such as irradiation with light such as ultraviolet rays or visible light, and heating. The polymerizable mixture is prepared by mixing a predetermined amount of the constituent components and uniformly mixing the components with a stirrer such as a mechanical stirrer. The light irradiation may be of any type as long as the first polymerizable mixture is cured. The heating may be performed by heating the first polymerizable mixture in an oven, a hot plate, or the like at a predetermined temperature. The heating temperature is, for example, 50 to 150.
° C, preferably 80 ° C to 100 ° C.

The thickness of the lower cladding layer is not particularly limited since it is variously selected depending on the intended optical waveguide device. For example, in the case of a multi-mode optical waveguide device, for example, it is 5 to 20 μm, and in the case of a single-mode optical waveguide device,
For example, it is 1 to 10 μm.

(2) The second step of the method of the present invention is a step of forming a core. First, a lower polymerizable mixture that has a higher refractive index when cured than the lower clad layer cured in the first step is prepared, and is applied on the lower clad layer to form a predetermined pattern. To form a core.

In the present invention, the core portion can be formed by various methods. For example, the following one method can be given as an example.

<First Method> The first method is based on this (2)
Applying a second polymerizable mixture containing at least a reactive oligomer represented by the structural formula (a) and a heat or photopolymerization initiator on the lower clad layer, and irradiating light through a mask. This is a method of curing the second polymerizable mixture in a pattern to obtain the core.

<Second Method> The second method is as follows.
The step (2) is performed by (4) at least the structural formula (a)
Applying a second polymerizable mixture containing a reactive oligomer represented by the formula (1) and a heat or photopolymerization initiator onto the lower cladding layer, (5) applying the second polymerizable mixture onto the lower cladding layer. Curing the polymerizable mixture by light irradiation,
(6) forming a resist film on the cured second polymerizable mixture and patterning the resist film;
(7) a step of etching the cured second polymerizable mixture in a pattern using the patterned resist film as a mask to obtain the core.

First, the first method will be described. First,
Apply a second polymerizable mixture on the lower cladding layer as described above. Next, the mixture is irradiated with light through a mask to form a latent image. The part irradiated with light is cured by the polymerization of the second polymerizable mixture. Since the second polymerizable mixture is not cured in the portion not irradiated with light, the core portion can be formed by removing the second polymerizable mixture in the non-irradiated portion (uncured portion) after light irradiation. .

It should be noted that the second polymerizable mixture differs only in the components and the mixing ratio thereof, and the mixing method and the like can be performed in the same manner as in the first step.

More specifically, the second polymerizable mixture as described above is applied onto the lower clad layer formed in the first step by a known application method such as a spin coating method, a dipping method, and an injection method. Then, light is irradiated through a mask in a pattern of the core portion to form a latent image in the second polymerizable mixture layer. Next, remove the mask,
The non-irradiated portion of the second polymerizable mixture layer is removed by developing with a developer such as an organic solvent,
A core ridge pattern is formed. For light irradiation, ultraviolet light, visible light, or the like can be appropriately selected and used. Also,
The development can be performed, for example, by immersing the substrate in a predetermined solvent, or by spraying or spraying a predetermined solvent. The solvent can be appropriately selected and used.

Next, the second method will be described. The second method is a method of forming a core ridge using a resist film as used in a lithographic method, instead of forming a core ridge through a mask as described above.

Specifically, steps (4) to (7) as described above can be performed.

Step (4) is a step of applying the second polymerizable mixture on the lower clad layer formed in the first step by a method such as spin coating.

The step (5) is a step of, after the step (4), exposing the entire surface of the second polymerizable mixture to light such as ultraviolet rays or visible light to cure the entire layer of the second polymerizable mixture. is there.

In the step (6), a resist film is applied on the second polymerizable mixture layer cured in the step (5) by a known method such as a spin coating method, and is subjected to a usual lithographic method such as light irradiation. This is a step of patterning the resist film into a desired pattern by the means.

Step (7) is a step of forming a core ridge pattern by etching using the pattern obtained in step (6) as a mask. The etching may be, for example, a dry etching process using oxygen gas plasma, but is not limited thereto. A means capable of etching the second polymerizable mixture layer may be appropriately selected and used. Next, the mask is removed to obtain a desired core ridge pattern (core portion).

The thickness of the core is not particularly limited since it is variously selected depending on the intended optical waveguide device. For example, in the case of a multimode optical waveguide device, for example, 3 to 20 μm
In the case of a single mode optical waveguide device, for example, 1
To 10 μm.

(3) The third step of the present invention is a step of forming an upper clad layer. In this step, a third polymerizable mixture is applied and cured so as to cover the lower clad layer and the core.

The third polymerizable mixture differs only in the components and the mixing ratio, and can be mixed in the same manner as in the first step. The third polymerizable mixture used in this step is selected to have the same refractive index as the first polymerizable mixture after curing. Preferably, the same polymerizable mixture as the first polymerizable mixture is used.

In the third step, first, a third polymerizable mixture is prepared, and this is subjected to a spin coating method, a dipping method,
The substrate is coated by a known coating method such as an injection method. Next, the polymerizable mixture is cured by applying a treatment such as irradiation with light such as ultraviolet rays or visible light, and heating. Light irradiation may be in any form as long as the third polymerizable mixture is cured. In addition, heating may be performed by heating the third polymerizable mixture in an oven, a hot plate, or the like at a predetermined temperature. The heating temperature is, for example, 50 to 150 ° C, preferably 80 to 100 ° C.

The thickness of the upper cladding layer is not particularly limited since it is variously selected depending on the intended optical waveguide device. For example, in the case of a multi-mode optical waveguide device, for example, it is 5 to 20 μm, and in the case of a single-mode optical waveguide device,
For example, it is 1 to 10 μm.

As described above, the optical waveguide of the present invention can be manufactured.

In the above description, an example in which a substrate is used has been shown. However, a lower cladding layer is formed without using a substrate by a technique used in the manufacture of a micromachine, and thereafter, the second step and the second step are performed. The optical waveguide of the present invention can be manufactured by sequentially performing the three steps. For example, by irradiating a laser beam or the like in a predetermined pattern shape from above the container filled with the first polymerizable mixture used in the present invention, the cured product of the first polymerizable mixture, that is, the lower clad layer After the formation, the above-described second step and third step are sequentially performed to manufacture the optical waveguide device of the present invention.

In the above description, a method of manufacturing an optical waveguide device using the polymerizable mixture containing the reactive oligomer of the above structural formula (a) for the lower cladding layer, the core, and the upper cladding layer has been described. In the present invention, if the polymerizable mixture containing the reactive oligomer of the above structural formula (a) is used for any one of the clad and the core, the reaction of the above structural formula (a) is not necessarily required for both the clad and the core. It is not necessary to use a polymerizable mixture containing a functional oligomer.

The method for producing an optical waveguide device according to the present invention is characterized in that the first polymerizable mixture and the third polymerizable mixture or the second polymerizable mixture are used even when the polymerizable mixture is not used. Alternatively, it can be applied as it is as described above by replacing it with a polymer material. As the polymer material, a conventional polymer material can be used.

Next, the manufacturing method of the present invention will be described in more detail with reference to the drawings. In the following description, a substrate is used, and a polymerizable mixture containing the reactive oligomer of the above structural formula (a) is used for both the clad and the core. Further, a case where the first method is used in the second step and development is performed using a solvent will be described as an example. The thickness and the like of each layer are as described above.

In the first step, first, as shown in FIG. 1A, a first polymerizable mixture is applied onto a substrate (11) by a conventional technique such as a spin coating method. Next, the layer is cured by irradiating ultraviolet rays or the like to the lower clad layer (1).
0) is obtained.

Next, as a second step, as shown in FIG. 1B, a second polymerizable mixture is spin-coated on the previously cured lower cladding layer (10) by a conventional method such as spin coating. And a second polymerizable mixture layer (12)
To form Subsequently, as shown in FIG. 1 (C), the second polymerizable mixture layer (12) is covered with a mask (13) having a predetermined pattern, and light (14) such as ultraviolet light is applied.
To form a latent image having a desired pattern on the second polymerizable mixture layer (12). By this light irradiation, the portion of the second polymerizable mixture that is exposed to the light is cured. Thereafter, development is performed to obtain a desired ridge pattern (15) (FIG. 1D). Development is accomplished by using a solution such as an organic solvent to remove the unpolymerized, uncured portion of the second polymerizable mixture. Spraying organic solvent,
Apply to the second polymerizable mixture by conventional methods such as dipping to remove uncured portions.

FIG. 2 shows an example of the Y-shaped core ridge (20) thus formed. As shown in FIG. 2, a desired Y-shaped core ridge (20) can be accurately formed on the lower cladding layer (10) on the substrate (11).

Next, as a third step, as shown in FIG. 1E, a layer made of a third polymerizable mixture covers both the core ridge (15) and the lower clad layer (10). To form This layer is cured by a curing means such as light irradiation to obtain an upper clad layer (16). In the method of the present invention, the third polymerizable mixture may be the same as the first polymerizable mixture.

Thus, an optical waveguide device (18) having a substrate (11), clads (10, 16) and a core (17) as shown in FIG. 1E can be manufactured.

In the method of the present invention, since the polymerizable mixture is in a liquid state, a uniform and flat layer can be formed even when the polymerizable mixture is applied on a surface having irregularities as in the third step. it can.

As described above, the present invention is based on the fact that a pattern having steep and smooth wall surfaces can be formed by curing a film by light irradiation and developing with an appropriate solvent. By using this pattern for the core ridge of the waveguide, the optical waveguide device of the present invention is realized.

The effectiveness of the present invention will be listed below.

(I) In the present invention, the polymerizable mixture containing the reactive oligomer represented by the above structural formula (a) is a liquid before curing and has high uniformity.
It has excellent transparency to light such as ultraviolet light and visible light. Therefore, when the film is cured by light irradiation, a sufficient resolution can be ensured even if the film becomes thick. Further, a waveguide with little scattering loss or the like can be realized.

(II) The above structural formula (a) in the present invention
Since the polymerizable mixture containing the reactive oligomer represented by the formula is a liquid before being cured, it can be flattened even when the substrate or the like has irregularities, and penetrates all over the irregularities. In addition, it is possible to form a film corresponding to various shapes. Therefore, various optical waveguide devices can be manufactured.

(III) In the polymerizable mixture containing the reactive oligomer represented by the structural formula (a) in the present invention, the oligomer is randomly bonded and cured, so that an optical waveguide having a small birefringence is realized. It is possible.

(IV) The above structural formula (a) in the present invention
Various kinds of polymerizable mixtures can be prepared from the polymerizable mixture containing the reactive oligomer represented by the formula (1) by mixing several kinds of oligomer materials. For this reason, the refractive index of the core and the clad constituting the optical waveguide device of the present invention can be controlled in a wide range, and various optical waveguide devices from a multi-mode waveguide to a single-mode waveguide can be obtained.

[0100]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto.

Example 1 A reactive oligomer represented by the above structural formula (a) (where n = 0) was used as a component (80
wt.), an alicyclic epoxy (ERL4206) (18 wt.%) as a diluent, and a sulfonium salt (0.1 wt.%) as a photopolymerization initiator (curing agent). A mixture was prepared. This was applied to a substrate by a spin coating method and cured by light to form a lower cladding layer. The refractive index of this lower cladding layer is 0.8 wavelength.
It was 1.472 at 5 μm. Next, a mixture containing a reactive oligomer having the same structure as one component (75 wt%) and a second polymerizable mixture containing 0.5 wt% of a photopolymerization initiator were prepared and applied to the lower cladding layer. The second polymerizable mixture was irradiated with ultraviolet light through a mask having a predetermined optical waveguide pattern (Y branch pattern). The irradiation amount was 2000 mJ / cm ² . After light irradiation, the second polymerizable mixture was developed with an organic solvent. As a result, a core ridge pattern (Y-branch shape) in which only the light-irradiated portion was hardened and remained was obtained. The refractive index of the core ridge after curing was 1.482 at a wavelength of 0.85 μm. After this,
On the ridge pattern and the lower cladding layer, the same polymerizable mixture as the first polymerizable mixture was applied and cured to produce an optical waveguide. By the above operation, the refractive index is 1.
A multi-mode channel waveguide (depth 40 μm, width 40 μm) having a 472 resin clad and a refractive index 1.482 core was produced.

This optical waveguide was cut by a dicing saw to 5c.
m, and the insertion loss was measured. The loss is 1 dB / cm or less at a wavelength of 0.85 μm, and 1.3 at 1.3 μm.
It was 1 dB / cm or less, and 3 dB / cm or less at 1.5 μm. The polarization dependence of the insertion loss is 1.3 μm.
However, it was 0.1 dB or less.

Example 2 A reactive oligomer represented by the above structural formula (a) (where n = 1) was used as a component (85
wt.), an alicyclic epoxy (ERL4206) (18 wt.%) as a diluent, and a sulfonium salt (0.1 wt.%) as a photopolymerization initiator (curing agent). A mixture was prepared. This was applied to a substrate and photo-cured to form a lower cladding layer. The refractive index of the lower cladding layer was 1.479 at a wavelength of 1.3 μm. Next, a mixture containing a reactive oligomer having the same structure as one component (90 wt%) and a photopolymerization initiator 1 wt
% Was prepared and applied on the lower cladding layer by spin coating. A predetermined optical waveguide pattern (Y branch pattern) is added to the second polymerizable mixture.
UV light was applied through a mask having The irradiation dose is 20
It was 00 mJ / cm ² . After light irradiation, the second polymerizable mixture was developed with an organic solvent. As a result, a core ridge pattern (Y-branch shape) in which only the light-irradiated portion was cured and remained was obtained. The refractive index of the core ridge after curing is
It was 1.484 at a wavelength of 1.3 μm. Thereafter, the same polymerizable mixture as the first polymerizable mixture was applied on the ridge pattern and the lower clad layer, and cured to produce an optical waveguide. By the above operation, the refractive index is 1.479.
Single-mode channel waveguide (having a depth of 6 μm) having a cladding made of
m, width 6 μm).

This optical waveguide was cut by a dicing saw to 5c.
m, and the insertion loss was measured. The loss was 1.7 dB / cm or less at a wavelength of 1.3 μm, and 3 dB / cm or less at a wavelength of 1.55 μm. In addition, even at a high temperature of 150 ° C., there was no significant increase in loss, and there was sufficient heat resistance.

Example 3 A lower clad layer was produced using the first polymerizable mixture (material of the lower clad layer) used in Example 2. Next, the second polymerizable mixture (core material) used in Example 2 was applied on the lower cladding layer, and then the entire surface was irradiated with ultraviolet light to form a flat core layer using the second polymerizable mixture. did. Next, a photoresist composition was applied on the core layer, and this was patterned to form a resist film. Next, using this resist film as a mask, dry etching was performed by reactive ion etching using an oxygen gas plasma reaction to obtain a core ridge having a Y-branch waveguide pattern. Thereafter, the same first polymerizable mixture as that used for the lower cladding layer was applied to the core ridge pattern and cured to produce a waveguide element.
By this operation, a single mode waveguide (6 μm deep,
6 μm in width). This optical waveguide was cut into a length of 5 cm using a dicing saw, and the insertion loss was measured. The loss is 1.4 dB / cm or less at a wavelength of 1.3 μm,
It was 3 dB / cm or less at 1.55 μm. The polarization dependence of the insertion loss was 0.1 dB or less even at a wavelength of 1.3 μm. Further, the excess loss of the branch is 0.2d.
The result was as good as around B. 85 ° C, 85% R
There was no remarkable increase in loss even under constant temperature and humidity of H, indicating that it had sufficient environmental reliability.

[0106]

According to the present invention, the use of the polymerizable mixture of the present invention makes it possible to realize an optical waveguide device that satisfies both low cost and high performance. Further according to the invention,
A method for manufacturing such an optical waveguide element at low cost can be provided.

According to the present invention, a high quality optical waveguide device can be easily realized, and by using the device of the present invention, it can be used in general optics and micro optics, and in optical communication and optical information. Various optical transmission systems can be introduced at low cost.

[Brief description of the drawings]

FIGS. 1A to 1E are schematic views showing each step of a method for manufacturing a luminous waveguide element of the present invention.

FIG. 2 shows a core ridge (Y branch) of the optical waveguide device of the present invention.
FIG.

[Explanation of symbols]

 Reference Signs List 10 lower clad layer 11 substrate 12 second polymerizable mixture for core 13 mask 14 ultraviolet ray 15 ridge pattern 16 upper clad layer 17 core part 18 multi-mode channel waveguide 20 Y-shaped ridge pattern

Continued on the front page (72) Inventor Hideyuki Takahara 2-3-1 Otemachi, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Inventor Toru Maruno 2-3-1 Otemachi, Chiyoda-ku, Tokyo Sun Within the Telegraph and Telephone Corporation (72) Inventor Norio Murata Within NTT Advanced Technology Co., Ltd. 2-1-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo (72) Inventor Akira Tomaru Shinjuku-ku, Tokyo 2-1-1, Nishishinjuku NTT Advanced Technology Co., Ltd. F-term (reference) 2H047 KA04 PA02 PA21 PA24 PA28 QA05 TA11 TA41 4J036 AB03 AB05 AB07 DB02 DB06 DB15 DC02 DC41 FB03 GA19 GA22 GA24 GA25 HA02 JA15

Claims (7)

[Claims] 1. An optical waveguide device having a waveguide comprising a core and a clad having a lower refractive index than the core,
A polymer obtained by curing a polymerizable mixture containing at least a reactive oligomer represented by the following structural formula (a) and a heat or photopolymerization initiator is used for at least one of the core and the clad. Optical waveguide device. Embedded image [In the formula, n is 0 or an integer of 1 to 10.] ] 2. The optical waveguide device according to claim 1, wherein the polymerizable mixture further includes an oligomer or a prepolymer having at least one carbon-carbon double bond in a molecule. Optical waveguide device. 3. A method for manufacturing an optical waveguide device having a waveguide comprising a core and a clad having a lower refractive index than the core, comprising: (1) at least a reactivity represented by the following structural formula (a): Applying a first polymerizable mixture containing an oligomer and a heat or photopolymerization initiator to a substrate and curing to form a lower cladding layer; [In the formula, n is 0 or an integer of 1 to 10.] (2) A second polymerizable mixture containing at least the reactive oligomer represented by the structural formula (a) and a heat or photopolymerization initiator is applied on the lower clad layer, and the second polymerization is performed. Curing the reactive mixture in a pattern to form the core, (3) a third polymerizable composition containing at least a reactive oligomer represented by the structural formula (a) and a heat or photopolymerization initiator. A method for manufacturing an optical waveguide device, comprising a step of applying a mixture on the lower clad layer and the core and curing the mixture to form an upper clad layer. 4. The method for manufacturing an optical waveguide device according to claim 3, wherein the step (2) comprises: at least a reactive oligomer represented by the structural formula (a); and heat or photopolymerization. A second polymerizable mixture containing an initiator is coated on the lower clad layer, and the second polymerizable mixture is cured in a pattern by irradiating light through a mask to obtain the core. A method for manufacturing an optical waveguide device, comprising: 5. The method for manufacturing an optical waveguide device according to claim 3, wherein the step (2) comprises: (4) at least a reactive oligomer represented by the structural formula (a); Or a step of applying a second polymerizable mixture containing a photopolymerization initiator on the lower clad layer; and (5) a step of curing the second polymerizable mixture applied on the lower clad layer by light irradiation. (6) forming a resist film on the cured second polymerizable mixture, and patterning the resist film; (7) using the patterned resist film as a mask, Etching the second polymerizable mixture in a pattern to obtain the core. 6. The method for manufacturing an optical waveguide device according to claim 3, wherein the first polymerizable mixture, the second polymerizable mixture, or the third polymerizable compound. A method for manufacturing an optical waveguide device, wherein at least one of the mixtures further includes an oligomer or a prepolymer having at least one carbon-carbon double bond in a molecule. 7. The method for manufacturing an optical waveguide device according to claim 3, wherein the third polymerizable mixture is the first polymerizable mixture. A method for manufacturing an optical waveguide device.