JP2007225704A - Method for manufacturing optical waveguide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve adhesive property of a self-forming optical waveguide to a transparent container or the like. <P>SOLUTION: An optical fibre 4 is fixed to the transparent container 3 (1.A), and a photo-setting resin liquid 1 is injected in (1.B) and is removed immediately. Then, unset photo-setting resin liquid 1 adheres to the inner surface of the transparent container 3 and the surface of the core 40 (1.C). When a photo-setting resin liquid 2 is injected, the photo-setting resin liquid 1 and the photo-setting resin liquid 2 are partly mixed with each other, but are not completely nor uniformly mixed with each other (1.D). The photo-setting resin liquids are irradiated with laser light through the optical fiber 4 to form an axial form self-forming optical waveguide core 20 by self-condensing property (1.E). The hardened part of the photo-setting resin liquid 1 condensed in density is formed on the connecting part 10. When removing the unset photo-setting resin liquids 1, 2, the self-forming optical wave guide core 20 is firmly stuck to the optical fiber and the transparent container, and is fixed without deviation even if touching the self-forming optical waveguide core 20 (1.F). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method of manufacturing an optical waveguide by photocuring a photocurable resin liquid in a self-forming manner to form a core and covering the outer periphery with a clad material.

  The applicant of the present application has developed a shaft-like cured product that can be used as a core of an optical waveguide by “photocuring a photocurable resin composition in a self-forming manner” and has made various proposals up to the present. I went. For example, the following patent documents 1 and 2 are mentioned.

The technique of patent document 2 uses the resin liquid which has adhesiveness at the time of hardening with respect to holding members, such as a container inner surface, a filter, or a mirror, to the photocurable resin liquid which forms the core of a self-forming optical waveguide. . As means for improving the adhesion to the holding member, a method of adding a silane coupling agent to the photocurable resin, or a primer such as a silane coupling agent or a urethane type or an epoxy type is applied to the surface of the holding member. There is a way. Thereby, the adhesiveness to the holding member of an optical waveguide is improved. Further, Patent Document 3 discloses a surface modification process of an optical wiring by forming a “roughened surface”, a plasma process or the like when bonding an optical transmission structure.
Japanese Patent No. 3444352 JP 2002-365594 A JP 2004-004487 A

  When a silane coupling agent is added to the photocurable resin liquid, which is the first conventional method, the viscosity of the photocurable resin liquid may increase over time due to the reaction of the silane coupling agent. The change in viscosity leads to a change in characteristics of the produced self-formed optical waveguide. That is, a problem arises in the temporal stability of the photocurable resin liquid. In addition, when a silane coupling agent is added to the photocurable resin liquid, low molecular components and the like generated by the reaction of the silane coupling agent affect the stability and transmission characteristics of the cured resin (self-formed optical waveguide). Further, when a silane coupling agent is added to the photocurable resin liquid, light scattering occurs due to micro nonuniformity of the cured resin, and the transmission characteristics of the self-forming optical waveguide deteriorate.

  When a coupling agent or primer is applied to the holding member, which is the second conventional method, productivity is reduced because a drying process or a curing process is required in addition to the application process.

  The process of forming a roughened surface on the holding member, which is the third conventional method, requires the use of harmful chemicals with high environmental impact, requires the use of a large-scale apparatus, and is a process such as a cleaning process. Therefore, the process itself is not easy, and it is a problem in terms of productivity. Further, transmission characteristics are deteriorated depending on the condition of surface roughness.

  The surface treatment such as the plasma treatment of the holding member, which is the above-mentioned conventional fourth method, requires a large-scale processing apparatus, and the treatment process is a photo-curing property performed by a conventional self-forming optical waveguide manufacturing method. It is inconsistent with the process using resin liquid.

  The present invention uses a self-forming optical waveguide and a transparent container, an optical fiber, an optical component, etc. without sacrificing transmission characteristics and productivity by a consistent process using a photocurable resin liquid as in the conventional self-forming optical waveguide manufacturing method. It is an object of the present invention to improve the adhesiveness with a low-cost, easily and stably without using a special device.

  The invention according to claim 1 is a method of manufacturing an optical waveguide in which a transparent container having an opening is filled with a photocurable resin liquid, and the photocurable resin liquid is photocured in a self-forming manner to form an axial core. In the method, the first photo-curing resin liquid is adhered to at least a portion to which the core inside the transparent container should contact, and the second photo-curing resin liquid is added to the core inside the transparent container. A second liquid filling step for filling a portion to be formed, and curing to form an axial core with light of a wavelength that cures both the first photocurable resin liquid and the second photocurable resin liquid. The first photocurable resin liquid and the second photocurable resin liquid can be copolymerized, and the cured product of the first photocurable resin liquid has adhesion to the transparent container. Characterized by good things.

  In a series of self-forming optical waveguides by the applicant of the present application, a photo-curing resin, which is generally said to have low adhesion, is used as a main material. When a photo-curing resin with good adhesion is selected in accordance with the target material (partner to be bonded, inner surface of container, filter, mirror, etc.), the transmission characteristics and productivity of the resulting self-formed optical waveguide are necessarily good. It did not become a thing. Therefore, the present invention is based on the idea that a photo-curing resin with good adhesion is not used for the entire core, and the photo-curing properties that are substantially different between the core end that requires adhesion and the core main portion that does not require adhesion. The resin can be selected.

  The part in which the present invention differs from the so-called primer technique is that it is not necessary to perform pretreatment, and it has a wavelength for curing both the first photocurable resin liquid and the second photocurable resin liquid. It is characterized by having a curing process that forms an axial core with light. The said hardening process produces the adhesiveness to the container inner surface of a core.

  Since the first photocurable resin liquid and the second photocurable resin liquid can be copolymerized, the cured product is naturally formed integrally even in the portion where they are mixed. Moreover, if a combination with good compatibility is used as a combination of the first photocurable resin liquid and the second photocurable resin liquid, problems such as white turbidity due to mixing of both can be avoided. Moreover, since the 1st photocurable resin liquid can be selected from the surface of adhesiveness with the transparent container inner surface, and the 2nd photocurable resin liquid can be selected from the surface of other transmission characteristics, selection of a photocurable resin liquid is possible. The degree of freedom is significantly improved. Thereby, the adhesiveness with the inner surface of the transparent container and the improvement of the transmission characteristics in the core can be achieved without difficulty.

  The first liquid adhering step of the first photocurable resin liquid can be completed in a short time by selecting a low-viscosity resin liquid, and does not require a drying process or a curing process. Does not reduce productivity.

  As described above, the adhesiveness between the self-forming optical waveguide core and the transparent container (housing) and the adhesiveness between the self-forming optical waveguide core and the optical fiber are excellent. Furthermore, when optical components such as filters and mirrors are inserted, the adhesion between the optical components and the self-forming optical waveguide core can be improved. At this time, a self-formed optical waveguide with low transmission loss can be produced in a short time. A self-forming optical waveguide can be produced by using a photo-curing resin material having poor adhesion in most of the cores except for both ends. Since both ends of the core are in good contact with the container and other holding members, for example, even if a step of cleaning the core surface and the container inner surface before filling with the clad material is provided, the core will not peel off.

  It is preferable to use a combination in which the first photocurable resin liquid and the second photocurable resin liquid are appropriately compatible and sufficiently adhere to each other after curing. For example, if both use an acrylate monomer, or both use an epoxy monomer, they can be copolymerized in both cases and exhibit strong adhesion.

  If a relatively low-viscosity material is used as the first photocurable resin liquid, the handling is easy, and the filling and removing of the material or the application time can be shortened. The “adhesiveness” is preferably a monomer or oligomer having a small molecular weight per polymerizable functional group. In this respect, a bifunctional monomer (oligomer) is preferable, and trifunctional or higher is more preferable. Moreover, the thing with smaller molecular weight is preferable. Since the cured product of the second photocurable resin liquid is a core, a material having a high refractive index is preferable. For example, what has an aromatic ring is preferable. Or the thing which has a polyoxyethylene chain and a polyoxypropylene chain from another viewpoint is preferable. The first photocurable resin liquid and the second photocurable resin liquid may each be a mixture.

  If the amount of the first photocurable resin liquid adhered to the transparent container and the optical fiber surface is reduced, the deterioration of the transmission characteristics in the cured product of the first photocurable resin liquid can be negligible. If the refractive index after curing of the first photocurable resin liquid is matched with the transparent container, the optical fiber, and the self-forming optical waveguide core, it is even better in the sense that the transmission characteristics are not deteriorated.

  0.1 g of DAROCUR 1173 photopolymerization initiator manufactured by Ciba Specialty Chemicals was added to 10 g of trimethylolpropane triacrylate manufactured by Wako Pure Chemical Industries, Ltd. and dissolved with sufficient stirring. This composition is designated as photocurable resin liquid 1 (first photocurable resin liquid). To 6 g of A-BPE-10 (modified bisphenol A diacrylate) manufactured by Shin-Nakamura Chemical Co., Ltd. and 4 g of APG-400 (polypropylene glycol diacrylate), 0.04 g of DAROCUR 1173 photopolymerization initiator manufactured by Ciba Specialty Chemicals In addition, it was sufficiently stirred to dissolve. This composition is designated as photocurable resin liquid 2 (second photocurable resin liquid).

  FIG. As shown in A, an optical fiber (Escamega manufactured by Mitsubishi Rayon Co., Ltd.) 4 is fixed to an acrylic transparent container 3 whose upper surface is a rectangular parallelepiped, and the end face 40c of the core 40 is disposed inside the transparent container 3. It was. The photocurable resin liquid 1 was injected there with a dropper (FIG. 1.B), and immediately, the photocurable resin liquid 1 was sucked and removed from the transparent container with a dropper without being cured. At this time, the uncured photocurable resin liquid 1 adhered and remained on the inner surface of the transparent container 3 and the surface of the core 40 of the optical fiber 4 in the transparent container 3 (FIG. 1.C). Next, the photocurable resin liquid 2 was additionally injected into the transparent container 3 (FIG. 1.D). At this time, FIG. The photocurable resin liquid 1 adhering to the surface of the transparent container 3 at the stage C and a part of the added photocurable resin liquid 2 were mixed, but they were not mixed completely uniformly. That is, only the photocurable resin liquid 1 or the concentration thereof was high on the inner surface of the transparent container 3 and the surface of the core 40. Next, a laser beam having a wavelength of 408 nm and an intensity of 30 mW was irradiated into the transparent container 3 through the optical fiber 4 to form an axial self-forming optical waveguide core 20 by self-condensing property (FIG. 1.E). At this time, it is considered that the concentration of the cured product of the photocurable resin liquid 1 is high in the connection portion 10 between the transparent container 3 of the self-forming optical waveguide 20 and the end face 40c of the core 40 of the optical fiber 4. When the uncured photocurable resin liquids 1 and 2 are removed, the self-forming optical waveguide core 20 is firmly adhered to the optical fiber 4 and the transparent container 3, and is displaced even when touching the self-forming optical waveguide core 20. It was fixed without any change (Fig. 1.F).

  A clad was formed around the self-formed optical waveguide core 20 thus manufactured by the same method as in Patent Document 2. For the cladding material, a composition obtained by adding 0.5 wt% of IRGACURE 1800 photopolymerization initiator manufactured by Ciba Specialty Chemicals to APG-700 (polypropylene glycol diacrylate) manufactured by Shin-Nakamura Chemical Co., Ltd. is cured with an ultraviolet lamp. did. When the insertion loss at a wavelength of 640 nm was measured for the produced linear optical waveguide device having a length of 14 mm, it showed excellent transmission characteristics of 0.13 dB.

[Comparative Example 1]
As in the first embodiment, an optical fiber (Escamega manufactured by Mitsubishi Rayon Co.) 4 is fixed to an acrylic transparent container 3 having a rectangular parallelepiped upper surface, and the end face 40c of the core 40 is placed inside the transparent container 3. Arranged (Figure 2.A). The photocurable resin liquid 2 adjusted in Example 1 was inject | poured there (FIG. 2.B). Next, laser light having a wavelength of 408 nm and an intensity of 30 mW was irradiated through the optical fiber 4 to form an axial self-forming optical waveguide core 20 by self-condensing property (FIG. 2.C). When the uncured photocurable resin liquid 2 is removed (FIG. 2.D), the adhesion between the self-forming optical waveguide core 20 and the inner surface of the transparent container 3 is insufficient, and the self-forming optical waveguide core 20 is lightly touched. The contact portion between the self-forming optical waveguide core 20 and the inner surface of the transparent container 3 has shifted.

  0.08 g of IRGACURE 1800 photopolymerization initiator manufactured by Ciba Specialty Chemicals was added to 10 g of 701A (2-hydroxy-3-acryloyloxypropyl methacrylate) manufactured by Shin-Nakamura Chemical Co., Ltd., and dissolved with sufficient stirring. This composition is referred to as a photocurable resin liquid 11 (first photocurable resin liquid). 6 g of A-BPE-10 (modified bisphenol A diacrylate) manufactured by Shin-Nakamura Chemical Co., Ltd. and 4 g of APG-400 (polypropylene glycol diacrylate), 0.04 g of IRGACURE 1800 photopolymerization initiator manufactured by Ciba Specialty Chemicals In addition, it was sufficiently stirred to dissolve. This composition is designated as photocurable resin liquid 12 (second photocurable resin liquid).

  FIG. As shown in A, the optical fiber 4 (Escamega manufactured by Mitsubishi Rayon Co., Ltd.) is fixed to the outside of the glass transparent container 3 whose upper surface is a rectangular parallelepiped, and the end face 40c of the core 40 is bonded to the outer wall of the transparent container 3. Thus, light can be introduced into the transparent container 3 from the other end of the optical fiber 4. The photocurable resin liquid 11 was poured into the transparent container 3 with a dropper (FIG. 3.B), and immediately, the photocurable resin liquid 11 was sucked and removed from the transparent container 3 with the dropper uncured. At this time, the uncured photocurable resin liquid 11 adhered to the inner surface of the transparent container 3 and remained (FIG. 3.C). Next, the photocurable resin liquid 12 was additionally injected into the transparent container 3 (FIG. 3.D). At this time, FIG. The photocurable resin liquid 11 adhering to the surface of the transparent container 3 in the stage C and a part of the added photocurable resin liquid 12 were mixed, but they were not mixed completely uniformly. That is, on the inner surface of the transparent container 3, only the photocurable resin liquid 11 or the concentration thereof was high. Next, a laser beam having a wavelength of 457 nm and an intensity of 4 mW was irradiated through the optical fiber 4 into the transparent container 3 to form an axial self-forming optical waveguide core 120 by self-condensing property (FIG. 3.E). At this time, it is considered that the concentration of the cured product of the photocurable resin liquid 11 was high in the connection portion 110 of the self-forming optical waveguide 20 with the transparent container 3. When the uncured photocurable resin liquids 11 and 12 were removed, the self-forming optical waveguide core 20 was firmly adhered to the transparent container 3 (FIG. 3.F).

[Comparative Example 2]
A self-forming optical waveguide core 120 was produced in the same manner as in Example 2 except that the step of injecting and removing the photocurable resin liquid 11 from the transparent container 3 was not performed. Adhesion between the self-forming optical waveguide core 120 and the inner surface of the transparent container 3 is insufficient, and when the self-forming optical waveguide core 120 is lightly touched, the contact portion between the self-forming optical waveguide core 120 and the inner surface of the transparent container 3 is shifted. Oops.

  In the same manner as in Example 2, an optical fiber (Escamega manufactured by Mitsubishi Rayon Co., Ltd.) 4 was fixed to the outside of the glass transparent container 3 having an open top surface of the rectangular parallelepiped (FIG. 4.A). On the inner surface of the transparent container 3, a photocurable resin liquid 11 was applied to a place to be connected to a self-forming optical waveguide core to be formed later (FIG. 4.B). Next, the photocurable resin liquid 12 was poured into the transparent container 3 while the photocurable resin liquid 11 was in an uncured state (FIG. 4.C). At this time, FIG. Although the photocurable resin liquid 11 applied to the inner surface of the transparent container 3 in the stage B and the injected photocurable resin liquid 12 were partially mixed, they were not mixed completely and uniformly. That is, on the inner surface of the transparent container 3, only the photocurable resin liquid 11 or the concentration thereof was high. Next, laser light having a wavelength of 457 nm and an intensity of 4 mW was irradiated through an optical fiber to form an axial self-forming optical waveguide core 120 by self-condensing property (FIG. 4.D). At this time, it is considered that the concentration of the cured product of the photocurable resin liquid 11 was high in the connection portion 110 between the self-forming optical waveguide 120 and the inner surface of the transparent container 3. When the uncured photocurable resin liquids 11 and 12 were removed, the self-forming optical waveguide core 120 was firmly adhered to the optical fiber and the transparent container 3 (FIG. 4.E).

Process drawing (sectional drawing) which shows the manufacturing method of the optical waveguide which concerns on one specific Example of this invention. Process drawing (sectional drawing) which shows the manufacturing method of the optical waveguide which concerns on a comparative example. Process drawing (sectional drawing) which shows the manufacturing method of the optical waveguide which concerns on the concrete other Example of this invention. Process drawing (sectional drawing) which shows the manufacturing method of the optical waveguide which concerns on another specific Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 11: 1st photocurable resin liquid 2, 12: 2nd photocurable resin liquid 10, 110: End surface 40c of the core 40 of the transparent container 3 or the optical fiber 4 in the edge part of a self-forming optical waveguide core 20, 120: Self-forming optical waveguide core 3: Transparent container 4: Optical fiber 40: Core of optical fiber 4 40c: End face of core 40 of optical fiber 4

Claims (1)

In a method of manufacturing an optical waveguide in which a transparent container having an opening is filled with a photocurable resin liquid and the photocurable resin liquid is photocured in a self-forming manner to form an axial core.
A first liquid adhering step of adhering the first photocurable resin liquid to at least a portion that should contact the core inside the transparent container;
A second liquid filling step of filling the second photocurable resin liquid into a portion where the core inside the transparent container is to be formed;
A curing step of forming the axial core with light of a wavelength that cures both the first photocurable resin liquid and the second photocurable resin liquid;
The first photocurable resin liquid and the second photocurable resin liquid can be copolymerized,
The method for producing an optical waveguide, wherein the cured product of the first photocurable resin liquid has good adhesion to the transparent container.

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