JPH0777637A - Optical element coupling method and refractive index image forming material - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a method for coupling optical elements, to improve the coupling efficiency in the case of optically coupling optical elements, and to facilitate their bonding. [Structure] The end faces of two optical elements are connected with a distance by a refractive index image forming material which also serves as an adhesive, and then the refractive index distribution forming material between those end faces is exposed to light through at least one optical element. And forming a refractive index profile having a condensing lens effect.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical element coupling method and a refractive index image forming material, and more specifically, to a method for coupling optical elements in optical communication, optical interconnection, etc., and the coupling used therefor. Regarding materials.

[0002]

2. Description of the Related Art Optical elements are used for optical interconnection,
It is used in various optical information processing systems such as optical communication.
In the optical element, light from a light source such as a semiconductor laser is transmitted using a waveguide or an optical fiber, and the transmitted light is restored to an electric signal by a photodiode or the like.

Therefore, a coupler for coupling the light emitting element or the light receiving element to an optical fiber or an optical waveguide is required. These couplers are described in, for example, the following documents. 1 Optical communication element optics-light emitting / receiving element, Hirosuke Yonezu, published optical book 2 Optical fiber technology in ISDN era, Katsuhiko Okubo, published by Science and Engineering 3 Optical communication manual, edited by Hiro et al., Published by Kagaku Shimbun According to the literature, the edge-emitting type semiconductor laser has a rectangular structure with an oscillation layer of several hundred nm × several μm, and the emission angle of light is 20 ° to 60 ° in the vertical direction and 5 ° to 20 ° in the horizontal direction. It is a degree. In addition, the surface emitting LED has a light emitting area diameter of 30 μm.
It is as large as ~ 40 μm and its emission angle is about 120 °.

On the other hand, the core diameter of a single mode optical fiber is about several μm to 10 μm, and the core diameter of a multimode optical fiber is about several tens μm. Therefore, when coupling an optical semiconductor element and an optical fiber, precise alignment on the order of 1 μm is required to reduce coupling loss. When precise alignment is performed and the end faces of the light emitting element and the optical fiber are butted against each other and directly coupled, for example, the coupling efficiency between the edge emitting semiconductor laser and the single mode optical fiber is 30%, and the edge emitting semiconductor laser is also used. And the coupling efficiency of the multimode optical fiber is 50%,
The coupling efficiency between the surface emitting light emitting diode and the multimode optical fiber is about 6%.

Further, a method of inserting a lens between the laser and the fiber has been studied as a method of coupling the edge-emitting semiconductor laser and the single mode optical fiber. In this case, the coupling efficiency is about 50%. Making it more and more difficult as the number of parts that require precise alignment increases. On the other hand, in the case of coupling the optical fiber and the waveguide, the coupling efficiency of 56 to 79% can be obtained by the direct coupling by making the core diameters of the waveguide and the fiber the same so as not to cause the axial deviation. .

However, the direct coupling is limited in the core diameter of the waveguide and the optical fiber that can be coupled with high efficiency, and is 1 μm.
There is a problem that coupling is not easy because it requires precise alignment on the order. Also, a method replacing the above-mentioned direct coupling or lens coupling has been proposed, and is disclosed in Japanese Patent Laid-Open No. 55-55
In Japanese Patent Laid-Open No. 43538/1985 and Japanese Patent Application Laid-Open No. 60-173508, a method of using a material whose refractive index changes by irradiation with light is proposed.

[0007]

However, the connection method of the optical coupler proposed in the former publication is such that an optical coupler base made of a substance whose refractive index changes in proportion to the intensity of light is
A method of manufacturing an optical coupler, wherein light is incident from a position where light should be input and output, the refractive index of the optical coupler base is changed, and an optical path is formed by itself.
In order to use this, it is necessary to arrange and fix the element such as an optical fiber to be coupled with this optical coupler. Therefore, for example, it becomes necessary to provide a hole for inserting an optical fiber or the like.

Further, in the latter publication, a phase change type photosensitive medium is arranged between two waveguides facing each other, and light is passed from both of the two waveguides toward the photosensitive medium. There has been proposed an optical waveguide connection method characterized by locally modifying the photosensitive medium to form a coupling waveguide. This publication aims to reduce the axial displacement loss by sandwiching a photosensitive medium between the waveguides to be connected to each other and forming a coupling waveguide in the waveguides. It is preferable that the thickness is 0.1 mm or less, and that the light passing toward the photosensitive medium is ultraviolet light, and as a result, a coupling waveguide is formed, which spreads slightly due to diffraction but hardly spreads. This publication uses the connection between the waveguides formed in the photosensitive medium, and the positional deviation between the waveguides to be connected is inherited between the waveguides formed in the medium. However, it is not possible to cope with a large displacement that exceeds the core diameter.

On the other hand, the following materials can be used as the optical coupler. For example, the former publication describes that a chalcogenide-based amorphous semiconductor or a polymer material containing a photopolymerizable monomer is used, and the latter publication describes a photopolymer of DuPont and KPR of Kodak. (Trade name) photoresist,
U.S.A. of Opticon Chemical Co. V. 57 (trade name) and the like are described as being known.

Further, there are the following refractive index image forming materials whose refractive index is changed by irradiating light. For example, there is a material composed of a thermoplastic polymer, an ethylenically unsaturated monomer and a polymerization initiator as described in JP-A-2-3081. Further, as described in JP-A-2-3082, an interpolymer containing a segment such as polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, and polyvinyl formal as a main part, or a group consisting of a mixture of these segments. There is a material consisting of a selected polymeric binder, an ethylenically unsaturated monomer and a photoinitiator. Also,
As described in Japanese Patent Laid-Open No. 3-50588,
There is a material composed of a solvent-soluble fluorine-containing polymeric binder, an ethylenically unsaturated monomer, and a photopolymerization initiator.
Further, as described in JP-A-3-36582, allyl diglycol carbonate and 2,2-bis (3,5-dibromo-4- (2-methacryloyloxyethoxy))
Materials such as phenyl) propane and a photopolymerization initiator have been proposed.

However, these materials have low heat resistance because they use a thermoplastic resin or a methacryloyl polymer as a binder. The present invention has been made in view of such a problem, provides a good coupling efficiency in the case of optically coupling optical elements, and provides an optical element coupling method in which they are easily adhered, and has heat resistance. An object is to provide a good optical element bonding material.

[0012]

The above-mentioned problems are solved by the steps of fixing the end faces of the two optical elements 3 and 4 with a space therebetween as shown in FIG. 1, and as an adhesive for the optical elements. And a step of supplying the refractive index image forming material 5 having the above function and having a high refractive index depending on the intensity of light in a specific wavelength band between the end surfaces of the two optical elements 3 and 4. Irradiating the refractive index image forming material 5 with light in the characteristic wavelength band from at least one of the end faces of the elements 3 and 4 to form a refractive index distribution 6 having a condensing lens effect. Achieved by combining method.

Alternatively, as illustrated in FIG. 7, the support 1 is a refractive index image forming material 5 having a function as an adhesive for an optical element and having a high refractive index depending on the intensity of light in a specific wavelength band. And the step of placing the two optical elements 3 and 4 on the support 1 with their end faces facing each other with the refractive index image forming material 5 interposed therebetween, and the two optical elements. Irradiating the refractive index image forming material 5 with light in the characteristic wavelength band from at least one of the end faces 3 and 4 to form a refractive index distribution 6 having a condensing lens effect. To achieve by.

Alternatively, as illustrated in FIG. 8, a support is provided with a refractive index image forming material 5 having a function as an adhesive for an optical element and having a high refractive index due to the intensity of light in a specific wavelength band. A step of adhering to the end surface of the first optical element 3 above 11, and an end surface of the second optical element 4 facing the end surface of the first optical element 3 and the first optical element. Three
A refractive index distribution 6 having a condensing lens effect by irradiating light of the specific wavelength band from at least one of the end faces of
And a step of forming B.

Alternatively, a material which exhibits a refractive index distribution upon irradiation with light of a specific wavelength band, which is an alicyclic compound or chain compound having an epoxy group, and an ethylenically unsaturated compound containing an aromatic ring or halogen. It is achieved by a refractive index image forming material comprising a compound, a polyfunctional acrylate or a polyfunctional methacrylate, and a photopolymerization initiator.

Alternatively, it is a material that produces a refractive index distribution by irradiating with light of a specific wavelength band, which is an organically modified silicon, an ethylenically unsaturated compound containing an aromatic ring or a halogen, a polyfunctional acrylate or a polyfunctional acrylate. It is achieved by a refractive index image forming material characterized by containing a methacrylate and a photopolymerization initiator. Alternatively, the organic modified silicon is achieved by a refractive index image forming material characterized by being any of acrylic modified silicon, methacrylic modified silicon, and epoxy modified silicon.

Alternatively, a material which produces a refractive index distribution by irradiating light of a specific wavelength band, and an ethylenically unsaturated compound containing silicon, and a general formula of R ₁ CH = CHCOOR
₂ (R ₁ is either CH ₃ or H, and R ₂ has 1 to 4 carbon atoms.
Is a chain compound or an alicyclic compound group) and a thermal polymerization initiator are dissolved in a solvent, and this is heated and stirred to prepare a copolymer solution, and Formed by adding an ethylenically unsaturated compound containing an aromatic ring or a halogen, a polyfunctional acrylate or polyfunctional methacrylate, and a photopolymerization initiator to the copolymer solution after allowing the polymer solution to cool to room temperature. Is achieved by a refractive index image forming material.

Alternatively, a material which produces a refractive index distribution by irradiating with light of a specific wavelength band, and an ethylenically unsaturated compound containing silicon and a general formula of R ₁ CH = CHCOOR
₂ (R ₁ is either CH ₃ or H, and R ₂ has 1 to 4 carbon atoms.
Of a chain compound or an alicyclic compound group), a polyfunctional acrylate or polyfunctional methacrylate, and a thermal polymerization initiator are dissolved in a solvent, and the resulting mixture is heated and stirred to perform copolymerization. A copolymer solution is prepared, the copolymer solution is allowed to cool to room temperature, and then an ethylenically unsaturated compound containing an aromatic ring or a halogen, a polyfunctional acrylate or a polyfunctional methacrylate, and a photopolymerization initiator are added. It is achieved by a refractive index image forming material characterized by being made by adding it to a polymer solution.

Alternatively, a thermosetting copolymer containing a acrylate or methacrylate having a hydrogen group at the terminal in its structural unit, which is a material which produces a refractive index distribution by irradiating with light of a specific wavelength band, It is achieved by a refractive index image-forming material comprising an ethylenically unsaturated compound containing a group ring or halogen, a polyfunctional acrylate or a polyfunctional methacrylate, and a photopolymerization initiator.

Alternatively, the thermosetting copolymer has chlorotrifluoroethylene, vinyltrimethylacetate, and a substance containing a hydroxyl group-terminated acrylate or methacrylate in its structural unit. Achieved by a rate imaging material. Alternatively, the ethylenically unsaturated compound containing an aromatic ring or halogen is allylcarbazole, methacryloyloxyethylcarbazole, acryloylethyloxycarbal,
It is achieved by a refractive index image forming material characterized by being any one of vinylcarbazole, vinylnaphthalene, naphthyl acrylate, tribromophenyl acrylate, dibromophenyl acrylate, phenoxyethyl acrylate, or a mixture of any thereof.

Alternatively, the step of sandwiching the refractive index image forming material between the end surfaces of two optical elements facing each other, and the light of a specific wavelength band from the end surface of at least one of the optical elements to the refractive index image forming material. And forming a refractive index distribution having a condensing lens effect. Alternatively, the optical element is any one of an optical fiber, a waveguide, a semiconductor laser, a light emitting diode, a photodiode, and a semiconductor optical amplifier.

Alternatively, it is achieved by an optical element coupling method characterized by including a step of curing the refractive index image forming material by light irradiation or heating. Alternatively, it is achieved by an optical element coupling method characterized in that the distance between the coupled optical elements is 0.1 mm or more.

[0023]

[Operation] According to the present invention, the end faces of two optical elements are connected at a distance by a refractive index image forming material that also serves as an adhesive, and then the end faces of at least one of the optical elements are provided between them. The refractive index distribution forming material is irradiated with light to form a refractive index distribution having a condensing lens effect.

In order to form this light-collecting refractive index distribution, it is necessary to have a condition that is contrary to the condition suitable for forming a waveguide in Japanese Patent Laid-Open No. 173508/1985. The distance must be 0.1 mm or more. In addition, the light for forming the refractive index distribution also has a large divergence of the beam after being emitted from the optical element,
It is desirable to use long wavelength light. However, since this wavelength is also limited by the characteristics such as the photosensitive wavelength range of the material, it is easy to increase the distance between the optical elements.

Therefore, the refractive index distribution forming material improves the coupling efficiency of the optical elements to each other, the high precision is not required for their alignment, and the yield is improved. Moreover, since the optical element to be combined is fixed and the refractive index distribution forming material is supplied, the refractive index distribution is formed using the light from this optical element, so that the optical element is fixed at the fixed position. In addition, since the refractive index distribution is formed by self-alignment, the optical element can be fixed by rough alignment, and further, JP-A-55-43538.
Such as the hole for inserting the optical fiber proposed in the publication,
There is no need to consider the arrangement and fixing of the elements to be combined.

Further, when the above-mentioned refractive index image forming material is adopted, the monomer is polymerized by irradiation of light of a specific wavelength to increase the monomer density, so that a lens effect of high refractive index according to the magnitude of light intensity is obtained. A refractive index profile is formed. In addition, when an optical element is combined with the refractive index image forming material and a refractive index distribution having the lens effect is formed by light irradiation from the optical element, and then light irradiation and heat treatment are performed, unreacted monomers react with each other. And the coupling efficiency is stabilized.

On the other hand, when the substance according to the present invention is used as the optical element bonding material, it has good heat resistance.

[0028]

Embodiments of the present invention will be described below with reference to the drawings. (A) Description of the First Embodiment of the Present Invention FIG. 1 is a sectional view showing the optical element coupling method of the first embodiment of the present invention. First, as shown in FIG. 1 (a), two optical fibers 3 and 4 are placed in the V groove 2 of the supporting substrate 1, and the end faces of the two optical fibers 3 and 4 are fixed with facing each other with a space therebetween. At this time, the distance between the fiber end faces is 0.1 mm or more.

Next, as shown in FIG. 1 (b), two optical fibers 3 and 4 are prepared by dissolving a refractive index image forming material whose refractive index is increased by irradiation with light having a specific wavelength into a solvent. Drip into the gap on the end face and around it. It is left to dry for several hours. As the refractive index image forming material, for example, an alicyclic compound or a chain compound having an epoxy group, an ethylenically unsaturated compound containing an aromatic ring or a halogen, a polyfunctional acrylate or a polyfunctional methacrylate, and photopolymerization Some include an initiator. Other materials will be described later in Examples.

Thereafter, the refractive index image forming material 5 is irradiated with light from at least one of the optical fibers 3 and 4. The wavelength of this light is preferably a long wavelength in order to increase the spread of the light, but specifically, the refractive index image forming material 5 is used.
Select in consideration of the photosensitive wavelength range of. The high-refractive index image is formed because the polymerization of the photopolymerized monomer having a high refractive index is started in the light-irradiated portion, and the density of the monomer is increased by this, and the unirradiated portion where the monomer density is low It is believed that there is a difference in refractive index between them. Specific examples of the refractive index image forming material forming the refractive index image forming material 5 will be described in the following examples.

As a result, a high refractive index image 6 based on the intensity distribution of the light emitted from the optical fibers 3 and 4 is formed on the refractive index image forming material 5. Specifically, as shown in FIG. 1 (c), when light is emitted from one of the optical fibers 3, a horn type high refractive index image 6 whose diameter spreads from the core is formed. . When light is emitted from both the optical fibers 3 and 4, a high-refractive-index image 6a having a most central portion, for example, a rhombic cross section, is formed as shown in FIG.

Thereafter, if necessary, the unreacted monomer is reacted by irradiation with light such as ultraviolet rays or heating to stabilize the refractive index image forming material 5, and at the same time, the material 5 is cured. Further, according to the light irradiation, the refractive index image forming material 5
The photosensitive dye remaining inside can be destroyed and the light transmittance can be increased. Through the above steps, the optical fibers 3 and 4 are optically coupled to each other and are fixed to the supporting substrate 1 by adhesion.

When a horn type high refractive index image 6 is formed in the refractive index image forming material 5 existing between the end faces of the two optical fibers 3 and 4, the high refractive index image 6 is formed. When the signal light is applied to the inside from one optical fiber 4 which is in contact with the widest end of the optical fiber, the light is condensed in the narrowest part by the lens effect of the high refractive index image 6 and the other optical fiber It will be incident on the core of No. 3. In general, infrared light such as a semiconductor laser is used as the signal light, and there are few materials that are sensitive to the infrared light, so that the wavelength is often different from the light for forming the refractive index image 6. .

As a result, even if the alignment accuracy of the optical fibers 3 and 4 is moderate, a high coupling efficiency can be obtained by the light collecting function of the refractive index image 6. By increasing the distance between the ends of the optical fibers 3 and 4 and increasing the length of the coupler, high isolation can be provided. Next, the results of analysis using the two-dimensional waveguide analysis method using Fourier transform (The Institute of Electronics and Communication Engineers paper; J66-C, 10 (1983) 732) are shown below.

Assuming that the refractive index distribution corresponding to the light irradiation intensity distribution is formed in the refractive index image forming material 5, after irradiation with light for high refractive index image formation from one optical core,
A refractive index distribution as shown in FIG. 3 is formed. In this analysis example, the optical fiber has a core diameter of 10 μm and an inter-core distance of 1
000 μm, optical axis deviation between core layers is 0 μm, refractive index of core layer is 1.60, refractive index of clad is 1.58, wavelength of light irradiating material is 488 nm, refractive index around material after refractive index image formation It is assumed that the refractive index difference between the high refractive index image of the material is 1.58 and its surroundings is 0.01.

The refractive index image-forming material having such a refractive index distribution has a wavelength of 1.3 μm from the core of one optical fiber 3.
When light of m is irradiated, the light propagation pattern becomes as shown in FIG. 4, and the light is focused on the core of the other optical fiber 4 by the high refractive index image. If the light loss due to the light absorption and the scattering by the refractive index image forming material 5 is excluded, theoretically a coupling efficiency of 90% or more is obtained.

By the way, in the case of coupling optical elements such as an optical fiber, a semiconductor laser, an optical waveguide, and an optical amplifying element, according to the above-mentioned method, the permissible width becomes large with respect to the initial optical axis deviation and angular deviation. . For example, when the optical axes of the core layers are deviated from each other by 10 μm, the refractive index distribution becomes as shown in FIG. 5 after irradiation of light for forming a high refractive index image from one optical core. In this example, two optical fibers 3,4
The core layer has a distance of 1000 μm, the core diameter is 10 μm, the core layer has a refractive index of 1.60, and the clad has a refractive index of 1.58. It is assumed that the refractive index around the material is 1.3 μm, the refractive index around the material is 1.58, and the refractive index difference between the high refractive index image of the material and its surroundings is 0.01.

Even when the optical axis shift is 10 μm, the coupling efficiency excluding the optical loss due to the material is theoretically 50% or more. The tolerance for alignment between the optical elements formed as described above becomes large. When the optical fiber and the semiconductor laser are optically coupled, as shown in FIG. 6 (a), the optical fiber 3 and the semiconductor laser 8 are placed on the support substrate 7, and the refractive index image forming material 5 is placed between them. Supply. After that, the refractive index image forming material 5 is dried to bond the optical fiber 3 and the semiconductor laser 8 to each other, and then light for high refractive index image forming is introduced from the optical fiber 3 to form the refractive index image forming material 5.
A horn type high refractive index image 6 is formed on the surface. As a result, the light emitted from the end face of the semiconductor laser 8 is collected by the high refractive index image 6 and enters the core of the optical fiber 3. (B) Description of Second Embodiment of the Invention In the above-mentioned embodiment, after the end portions of the two optical elements are opposed to each other, the refractive index image forming material is supplied to the gap and its periphery. It is also possible to place two optical elements on a support substrate which is thickly provided with the rate-imaging material and to combine the elements.

Next, the embodiment will be described with reference to FIG. First, as shown in FIG. 7A, after the refractive index image forming material 5 in which a solvent is dissolved is dropped into the V groove 2 of the supporting substrate 1,
As shown in FIG. 7B, the two optical fibers 3 and 4 are placed in the V groove 2 so that the refractive index image forming material 5 is sandwiched by the end faces. Next, after leaving the refractive index image forming material 5 for several hours to dry, as shown in FIG. 7 (c), light for forming a high refractive index image is introduced from at least one core of the optical fiber 3. The refractive index image forming material 5 is irradiated with light to form the high reflectance portion 6 described in the first embodiment.

Thereafter, if necessary, the refractive index image forming material is cured by irradiation with light such as ultraviolet rays or heating, as in the first embodiment. The optical fibers 3 and 4 thus connected are bonded and fixed to the supporting substrate 1 by the refractive index image forming material 5 as in the first embodiment, and the high refractive index image 6 formed therein is formed. This suppresses the divergence of light and propagates the light from one optical fiber 4 to the other optical fiber 3 as shown in FIG. 7 (d). (C) Description of Third Embodiment of the Invention In the above two embodiments, a refractive index image forming material is provided between and around the two optical element end faces to allow light to pass through the material. However, the light emitted from the light emitting element is made to enter the optical fiber or the light receiving element through the space,
Alternatively, light propagating in space may be received by a light receiving element.

Next, optical coupling when transmitting and receiving light propagating in space will be described. First, as shown in FIG. 8A, the refractive index image forming material 5 is applied to the light input / output portion of the first optical fiber 3, and this is dried and fixed to the support substrate 11. Then, from the optical fiber 3 to the refractive index image forming material 5
The light for changing the refractive index is output to, and as shown in Fig. 8 (b),
A horn-type high-refractive-index image 6B is formed in which the space side is widened by the light irradiation intensity distribution. After that, if necessary, the refractive index image forming material is cured by irradiation with light such as ultraviolet rays or heating.

As shown in FIG. 8 (d), light may be emitted from both of the two optical fibers 3 and 4 to form a high refractive index image 6C having the widest center. Next, as shown in FIG. 8 (c), when the end surface of the second optical fiber 4 is arranged so as to face the high refractive index image 6B, the light emitted from the second optical fiber 4 is collected by the high refractive index image 6B. And enters the core of the first optical fiber 3. In this case, the positioning of the second optical fiber 4 does not require high accuracy.

Next, the case where the semiconductor laser and the optical fiber are optically coupled with each other through a space will be described with reference to FIG. 6 (b). After the optical fiber 3 is first placed on the support substrate 9 and the refractive index image forming material 5 is supplied to the tip thereof, when the refractive index image forming material 5 is irradiated with light through the optical fiber 3, the space side is moved by the irradiation intensity distribution of the light. A horn-shaped high-refractive-index image 6B that widens is formed on the refractive-index image forming material 5. When light is emitted from the semiconductor laser 8 so as to face the high refractive index image 6B, the light is focused by the high refractive index image 6B and enters the optical fiber 3.

As described above, the present invention is effective when light enters and exits between optical elements fixed at distant positions or when a spatial light beam is entered into an optical-electrical conversion element. In the above description of the present embodiment, after mounting the optical element on the support substrate,
Although the refractive index image forming material is supplied to at least the tip portion thereof, the refractive index image forming material may be supplied to the supporting substrate before the optical element is mounted on the supporting substrate. (D) Description of Fourth Embodiment of the Present Invention In the above embodiment, two optical elements to be connected are:
Although the optical fiber is taken as an example, the optical fiber, the waveguide, the semiconductor laser, the semiconductor optical amplifier, the waveguide photodiode,
The same coupling method as described above may be used when coupling the same optical element or different optical elements among the edge emitting type light emitting elements.

The direction of light irradiation when forming a high refractive index image on the refractive index image forming material supplied between the end faces of two optical elements and the periphery thereof is, for example, when an optical fiber and a waveguide are coupled. The light is irradiated to either one or both. Further, when the optical fiber or the waveguide and the photodiode are coupled to each other, light is emitted only from the optical fiber or the waveguide to form a cone type high refractive index image. According to this, the light converging property due to the high refractive index image disappears, but when propagating divergent light, it becomes a propagation beam pattern in which divergence is suppressed by self-focusing due to the cone type high refractive index image, It is possible to improve the intensity of light incident on the light receiving portion of the photoelectric conversion element.

For example, as shown in FIG. 6 (c), a photodiode 13 having a light-receiving surface of 50 μm in diameter is fixed, and the light-receiving surface is provided with a gap of 1 mm so that the end faces of the optical fibers 3 are opposed to each other and the state is maintained. Meanwhile, the refractive index image forming material 5 is supplied to the gap and its periphery. And the optical fiber 3
Light having a wavelength of 488 nm was introduced from the above, and this light was irradiated to the refractive index image forming material 5 to form a high refractive index image 6D. And
It was found that almost 100% of the light is focused on the light receiving surface when the material has a refractive index difference of 0.01 at the maximum. On the other hand, when the refractive index distribution was not formed in the above refractive index image forming material, the light incident on the light receiving surface of the photodiode was about 47%. (E) Description of Fifth Embodiment of the Invention In this embodiment, experimental results will be described with and without forming a high refractive index image on the refractive index image forming material.

As shown in FIG. 9 (a), after the glass tube 20 with the lateral groove 21 having a diameter of 145 μm was attached to the supporting substrate 22, the diameter of the clad was 125 μm and the diameter of the core was 1 μm.
The first and second optical fibers 23 and 24 of 0 μm were inserted from both ends of the glass tube 20. In the glass tube 20,
The end faces of the two optical fibers 23 and 24 were located on both sides of the lateral groove 21, and the distance between them was 400 μm. In this state, the optical fibers 23 and 24 are attached to the adhesive 26
It was fixed to the support substrate 22 by.

Next, the refractive index image forming material 25 shown in Table 1
Was dropped into the lateral groove 21 of the glass tube 20, filled between the optical fibers 23 and 24 as shown in FIG. 9 (b), and left to dry.

[0049]

[Table 1]

The second optical fiber 24 is connected to a light intensity measuring device (not shown), and then a laser focusing holder (not shown) is used to add a wavelength 63 to the first optical fiber 23.
When He-Ne laser light of 2.8 nm was introduced, the intensity of light incident on the optical intensity measuring instrument through the second optical fiber 24 was 410 nW. In addition, when the He—Ne laser light was incident on the light intensity measuring device only through another optical fiber (not shown), the light intensity was 43 μW.

The measured value of these light intensity measuring devices is the average of the upper limit value and the lower limit value when measured for about 1 minute (hereinafter,
the same). Next, the second optical fiber 24 was removed from the light intensity measuring device, and the refractive index image forming material 25 was irradiated with the argon laser light having a wavelength of 488 nm for about 50 minutes through the optical fiber 24 using the laser focusing holder. The light intensity was set to 1000 nW. As a result, a high refractive index image 26 is formed on the refractive index image forming material 25, as shown in FIG. 9 (c).

After this, the second optical fiber 24 is connected to a light intensity measuring device, and as shown in FIG. 9 (d), the second optical fiber 23 again passes light having a wavelength of 632.8 nm through the first optical fiber 23. When it is introduced into the fiber 24, its light intensity measuring device is 678
A value of 0 nW was shown. Therefore, by irradiating with the argon laser beam, the high refractive index image 2 is formed on the refractive index image forming material 25.
It is confirmed that 6 was formed.

As a result, the intensity of the laser light propagated from the first optical fiber 23 to the second optical fiber 24 was increased by about 16 times, and the effect of forming a high refractive index image was confirmed. The optical coupling efficiency is calculated to be about 16%. Note that the refractive index image forming materials shown in Table 1 are also applied to the first to fourth examples, in which the portion irradiated with the argon laser light is polymerized with the monomer and the intensity distribution thereof is changed. The monomer density increases and the refractive index increases. The refractive index image forming material also functions as an adhesive. (F) Description of the sixth embodiment of the present invention The first and second optical fibers 23 and 24 were installed and fixed in the glass tube 20 by the same method as in the fifth embodiment.

Next, the supporting substrate 22 supporting the glass tube 20 is placed on a heating table (not shown), and the refractive index image forming material 25 is put into the two optical fibers 23, as in the fifth embodiment. Two
It was filled between the end faces of No. 4 and heated and dried at a temperature of 60 °. Next, the second optical fiber 24 is connected to a light intensity measuring device, and the He-Ne laser light is passed through the first optical fiber 23 and the refractive index image forming material 25 using the laser focusing holder to the second optical fiber 24. Introduced into, the light intensity meter showed a light intensity of 110 nW.

After this, the wavelength of 4
By introducing a laser beam of 88 nm, the refractive index image forming material 25 is
Irradiate for 0 minutes. After this, cooling was performed at a temperature decrease rate of 0.5 ° C./min. Then, the second optical fiber 24 was connected to a light intensity measuring device, He-Ne laser light was introduced into the first optical fiber 23 again, and the intensity of the light passing through the second optical fiber 24 was measured. There was 5520 nW.

Therefore, after heating and drying the refractive index image forming material 25, the material is irradiated with an argon laser beam to form a high refractive index image, whereby the first optical fiber 23 and the second optical fiber 23 are irradiated. He-N incident on fiber 24
The intensity of the e-laser light was increased about 50 times, and the effect of high refractive index image formation was confirmed. The optical coupling efficiency is calculated to be about 13%.

From the above, it was found that the heat treatment at about 60 ° C. before forming the high refractive index image 26 on the refractive index image forming material 25 has no adverse effect. (G) Description of the seventh embodiment of the present invention The first and second optical fibers 2 described in the fifth embodiment.
When the diameters of the clad and the core of 3, 24 were made different and the refractive index image forming material 25 was changed, the following results were obtained.

For example, the clad diameter of the first optical fiber 23 is 125 μm, the core diameter is 10 μm, and the clad diameter of the second optical fiber 24 is 125 μm and the core diameter is 50 μm.

[0059]

[Table 2]

Then, the first optical fiber 23 is connected to the light intensity measuring device, and the wavelength 632.8 is connected to the second optical fiber 24.
The light intensity of the light intensity measuring instrument when entering the light of nm is 55 nW
Met. Next, the first optical fiber 23 is removed from the light intensity measuring device, ultraviolet rays are introduced into the first optical fiber 23, and 2
Refractive index imaging material 2 between two optical fibers 23, 24
Irradiate 5 to 30 minutes.

After that, the second optical fiber 24 is connected again to the light intensity measuring instrument, and the light intensity measuring instrument when the light of wavelength 632.8 nm is introduced through the first optical fiber 23 and the high refractive index image 26. The light intensity of 1730 nW was 1,730 nW, and the light intensity propagating through the two optical fibers 23 and 24 was increased by about 31 times as compared with that before the ultraviolet irradiation. Note that the refractive index image forming materials shown in Table 2 are also applied to the first to fourth examples, and the monomer is polymerized in the portion irradiated with the argon laser light, and the intensity distribution is changed according to the intensity distribution. The monomer density increases and the refractive index increases. The refractive index image forming material also functions as an adhesive. (H) Description of Eighth Embodiment of the Invention The refractive index image forming material of this embodiment is prepared as follows.

First, 1.6 g of acrylic modified silicone varnish KR9706, 0.8 g of methyl methacrylate, 0.3 g of glycidyl methacrylate and 0.04 g of azobisisobutyronitrile were dissolved in 7.2 g of dioxane. This was heated and stirred at 70 ° C. for 1 hour. Then, after allowing it to cool to room temperature, 40 μl each of trimethylolpropane triacrylate and neopentyl glycol diacrylate were dropped into it, and after stirring them, they were further heated and stirred at 70 ° C. for 1 hour. did.

Then, after allowing them to cool to room temperature, 1.0 g of tetrahydrofuran, 0.66 g of allylcarbazole, and 0.6 g of N-vinylcarbazole were added to them.
6 g, trimethylol propane triacrylate to 0.
66 g, 0.04 of biimidazole (B1225, Tokyo Kasei)
g, 0.04 g of methyltriazolethiol and a cyclopentanone dye (NKX1460, Nihon Sensitive Dye) were added.

This completes the production of the refractive index image forming material. After this, the same first and second optical fibers 23 and 24 used in the seventh embodiment were put into the glass tube 20. The first optical fiber 23 is connected to a light intensity measuring device (not shown) in a state where nothing is filled between the two optical fibers 23 and 24, and the second optical fiber 24 has a wavelength of 632.8 nm. When the light of
It showed a light intensity of μW.

On the other hand, a wavelength of 63 is transmitted through another optical fiber.
When 2.8 nm light was input to the light intensity measuring device, it was 60μ
The light intensity of W is shown. Next, the above-mentioned refractive index image forming material 25 was dropped into the lateral groove 21 of the glass tube 20, the material 25 was filled between the two optical fibers 23 and 24, and this state was left for 14 hours and dried. .

Then, the first optical fiber 23 is connected to a light intensity measuring device, and the second optical fiber 24 has a wavelength of 632.8.
When light of nm wavelength was introduced, the light intensity measuring device showed a light intensity of 9 μW. Next, the refractive index image forming material 25 was irradiated with the argon laser light through the second optical fiber 24 for 80 minutes. Thereby, the high refractive index image 26 is formed.

After this, another optical fiber is used to set the wavelength 4
The light intensity when connecting 88nm light to the light intensity measuring device is 40
It was nW. When the first optical fiber 23 was connected to the light intensity measuring instrument and the light of 632.8 nm was introduced into the second optical fiber 24, the light intensity of the light intensity measuring instrument was 30 μW.
Its binding efficiency is calculated to be 50%. (I) Description of Ninth Embodiment of the Invention The refractive index image forming material of this embodiment is prepared as follows.

First, 1.6 g of acrylic modified silicone varnish KR9706, 0.8 g of methyl methacrylate, 0.4 g of glycidyl methacrylate and 0.04 g of azobisisobutyronitol were dissolved in 7.2 g of dioxane. Was heated and stirred at 70 ° C. for 2 hours. Next, after allowing this to cool to room temperature, 0.66 g of allylcarbazole and 0.66 g of N-vinylcarbazole were added.
Trimethylolpropane triacrylate 0.66
g, 0.04 g of biimidazole, 0.04 g of methyltriazolethiol, and 0.0004 g of cyclopentanone dye were added and stirred. This completes the production of the refractive index image forming material.

Using this material, the wavelength 63 of the eighth embodiment was used.
The experiment was performed using light having a wavelength of 1.3 μm instead of the light having 2.8 nm. First, the same first and second optical fibers 23 and 24 as those used in the eighth embodiment were put in the glass tube 20. Next, the refractive index image forming material 25 shown in the eighth embodiment is dropped into the lateral groove of the glass tube, and the two optical fibers 23, 2 therein are dropped.
The material 25 was filled in during 4 and left in this state for 17 hours to dry.

Then, the first optical fiber 23 was connected to a light intensity measuring device (not shown), and light having a wavelength of 1.3 μm was introduced into the second optical fiber 24.
It showed a light intensity of μW. When light of the same wavelength was input to the light intensity measuring device through another optical fiber (not shown), a light intensity of 180 μW was shown.

Then, the high refractive index image 26 was formed by irradiating the refractive index image forming material 25 with the argon laser light through the second optical fiber 24 for 80 minutes. After that, the first optical fiber 23 was connected to the light intensity measuring instrument, and the light intensity of the light intensity measuring instrument when the light of 1.3 μm was introduced into the second optical fiber 24 was 170 μW.

By the way, if the refractive index image forming material 25 is left as it is, unreacted monomers therein are polymerized with the lapse of time, so that the light intensity is lowered and the stability is lacking. Therefore, after forming the above-described high refractive index image 26 and measuring the light intensity, ultraviolet rays were externally irradiated for 160 minutes, and further 10 minutes after the irradiation was started, the whole was heated at 40 ° C. After this, the first optical fiber 23, the high refractive index image 2
6. When the intensity of the light passing through the second optical fiber 24 was measured, it was about 100 μW.

When this was allowed to stand for 17 hours and the optical imaginary degree was measured again, it was found that the value hardly changed, and it was found that the light intensity did not decrease due to ultraviolet irradiation and heating and was stable. all right. (J) Description of Tenth Embodiment of the Invention The refractive index image forming material of this embodiment is prepared as follows.

First, in 4.0 g of dioxane, 0.1 g of silicon-containing monomer (V4800, Chisso), 0.35 g of methyl methacrylate, 0.35 g of trifluoromethyl methacrylate and 0.15 of glycidyl methacrylate.
g, 0.02 g of azobisisobutyronitrile was dissolved, and this was heated and stirred at 70 ° C. for 1 hour. Then, after allowing this to cool to room temperature, 40 μl each of trimethylolpropane triacrylate and neopentyl glycol diacrylate were dropped therein, and after stirring them, they were further heated and stirred at 70 ° C. for 6 hours.

Next, after allowing to cool to room temperature, 1.0 g of tetrahydrofuran and 0.25 of allylcarbazole are added.
g, N-vinylcarbazole 0.25g, methacryloxyethyloxycarbazole 0.25g, trimethylolpropane triacrylate 0.25g, and biimidazole (B1225, Tokyo Chemical Industry Co., Ltd.) 0.04g.
g, 0.04 g of methyltriazolethiol, and a cyclopentanone dye (NKX1460, Japan Sensitive Dye).

This completes the production of the refractive index image forming material. Next, as shown in FIG. 10 (a), the maximum width is 300
A first glass plate 30 having a size of 30 × 30 × 5 mm having a V groove 31 of μm was used, and one end face had a thickness of 0.
One surface of the 2 mm second glass plate 32 was bonded. And
The other end of the optical fiber 33 having the connector connected to one end and the vicinity thereof were left bare and fitted into the V groove 31 of the first glass plate 30, and the other end was fixed so as to be 1 mm away from the second glass plate 32.

Next, as shown in FIG. 10 (b), the semiconductor laser 34 is set on the fine movement stage 37, and its light output portion is opposed to the end face of the optical fiber 33 via the second glass plate 32. . Further, the FC connector at one end of the optical fiber 33 was connected to a light intensity measuring device (not shown). When a current of 40 mA was made to oscillate in the semiconductor laser 34 to cause it to emit light, the light intensity of the light intensity measuring device was 15 nW.

Next, as shown in FIG. 10 (c), the above-described refractive index image forming material 35 was dropped between the end face of the optical fiber 33 and the second glass plate 32 and dried. And
The refractive index image forming material 35 was irradiated with the argon laser light having a wavelength of 515 nm through the optical fiber 33 for 150 minutes. As a result, a horn type high refractive index image 36 is formed. After that, when the semiconductor laser 34 was made to emit light again, the light intensity of the light intensity measuring device rose to 190 nW.

The refractive index image forming material of this embodiment is also applied to the first to fourth embodiments, and the monomer is polymerized in the portion irradiated with the argon laser beam, and the intensity distribution is changed. Accordingly, the monomer density increases and the refractive index increases. The refractive index image forming material also functions as an adhesive. (K) Description of the eleventh embodiment of the present invention The above-described refractive index image forming material is formed not only by the above-described refractive index image having a condensing lens effect but also by interference exposure with coherent light. The formed interference fringe image can be formed as a refractive index image. The characteristics when a refractive index image is formed from an interference fringe image to create a hologram will be described below.

First, a refractive index image-forming material shown in Table 3 was coated on a 70 × 70 mm glass substrate with a doctor blade and dried in a nitrogen box for 1 hour and then in an oven at 70 ° C. for 10 minutes.
This is used as a photosensitive plate.

[0081]

[Table 3]

A transparent hologram image having a spatial frequency of 2500 lines / nm and an inclination angle of 0 degree was exposed on the photosensitive plate by using an argon laser of 488 nm. The exposure intensity was 2 mW / cm ² , and the exposure time was 200 seconds. After exposing the photosensitive film to He-Ne
As a result of measuring the diffraction efficiency (ηs: diffraction efficiency during s-polarized light reproduction, ηp: diffraction efficiency during p-polarized light reproduction) using laser light, η
s = 55% and ηp = 80%.

Next, the transmission hologram was heated in an oven at 80 ° C. for 1 hour. As a result of measuring the diffraction efficiency again, ηs = 19% and ηp = 74%. The film thickness was 23 μm. The film thickness was measured with a stylus membrane pressure gauge (Alphastep, Tencor). (L) Description of the twelfth embodiment of the present invention In this embodiment, a hologram image will be described.

First, a 70 × 70 mm glass substrate was coated with the refractive index image-forming material shown in Table 4 by a doctor blade and dried in a nitrogen box for 1 hour and then in an oven at 70 ° C. for 10 minutes,
This is used as a photosensitive plate.

[0085]

[Table 4]

Argon laser light 488 nm was applied to the photosensitive plate.
A mirror reflection hologram image with an incident angle of 45 degrees was exposed using light. The exposure intensity was 1 mW / cm ² , and the exposure time was 400 seconds. After exposure, the transmission spectrum was measured at normal incidence using an instantaneous spectrophotometer (MCPD-100, Otsuka Electronics).
As a result, a spectrum in which a transmittance-decreasing region due to diffraction was observed near the wavelength of 540 nm was obtained. Diffraction efficiency is 48
%, The diffraction wavelength width was 9 nm.

Next, the reflection hologram was heated in an oven at 80 ° C. for 1 hour. Then, the transmission spectrum was measured in the same manner as in Example 12, and as a result of calculating the diffraction efficiency and the diffraction wavelength width, the diffraction efficiency was 69%, the diffraction wavelength width was 28 nm, and the film thickness was 26 μm.
It was m. (M) Description of Thirteenth Embodiment of the Present Invention In this embodiment, a hologram image will be described.

First, a refractive index image-forming material shown in Table 5 was coated on a 70 × 70 mm glass substrate with a doctor blade and dried in a nitrogen box for 1 hour and then in an oven at 70 ° C. for 10 minutes.
This is used as a photosensitive plate.

[0089]

[Table 5]

This photosensitive plate was prepared in the same manner as in the eleventh embodiment.
The transmission hologram was exposed. As a result of measuring the diffraction efficiency, ηs = 75% and ηp = 49%. Next, the transmission hologram was heated in an oven at 80 ° C. for 1 hour. As a result of measuring the diffraction efficiency again, ηs = 82% and ηp = 87%. The film thickness was 31 μm. Furthermore, the acrylic modified silicones shown in Table 5 are replaced with epoxy modified silicones (SR2115,
Instead of Toray Dow Corning), a curing agent (SR2115K
, Toray Dow Corning) 0.05 g was added to prepare a solution, and a hologram was prepared in the same manner. As a result, the diffraction efficiency was ηs =
It was 78% and ηp = 70%. (N) Description of Fourteenth Embodiment of the Present Invention In this embodiment, a hologram image will be described.

First, the refractive index image forming material used in Example 13 was applied in the same manner to manufacture a photosensitive plate. Argon laser 488 nm light was used for the photosensitive plate, and the incident angle was 30 degrees −60.
The reflection hologram was exposed using a reflection hologram production optical system. Then, the transmission spectrum was measured in the same manner as in the eleventh embodiment, and the characteristics were examined.
32%, the diffraction wavelength width was about 9 nm.

Next, the reflection hologram was heated in an oven at 80 ° C. for 1 hour. As a result of measuring the spectrum again and examining the characteristics, the diffraction efficiency is 42% and the diffraction wavelength width is about 14 nm.
Met. (O) Description of the fifteenth embodiment of the present invention In this embodiment, a hologram image will be described.

First, the refractive index image forming material prepared in Example 7 was applied to a 70 × 70 mm glass substrate with a doctor blade and dried in a nitrogen box for 1 hour and then in an oven at 70 ° C. for 10 minutes. Argon laser 488 nm on this photosensitive plate
The reflection hologram was exposed using light and a reflection hologram creating optical system with an incident angle of 30 ° to 60 °.

As a result of measuring the transmission spectrum and examining the characteristics in the same manner as in Example 11, the diffraction efficiency was 41% and the diffraction wavelength width was about 9 nm. (P) Description of Sixteenth Embodiment of the Present Invention Next, a refractive index image forming material will be described. First, the refractive index image forming material is composed of the following substances.

The first refractive index image forming material is an alicyclic compound or chain compound having an epoxy group, an ethylenically unsaturated compound containing an aromatic ring or a halogen, a polyfunctional acrylate or a polyfunctional methacrylate, It has a photopolymerization initiator. The second refractive index image forming material has an organic modified silicon, an ethylenically unsaturated compound containing an aromatic ring or a halogen, a polyfunctional acrylate or a polyfunctional methacrylate, and a photopolymerization initiator. The organic modified silicon is, for example, either acrylic modified silicon, methacrylic modified silicon, or epoxy modified silicon.

The third refractive index image forming material is formed by the following method. First, an ethylenically unsaturated compound containing silicon, an ethylenically unsaturated compound represented by the general formula R ₁ CH = CHCOOR ₂ , and a thermal polymerization initiator are dissolved in a solvent, and this is heated and stirred to obtain a copolymer. Make a solution. Next, after allowing the copolymer solution to cool to room temperature,
An ethylenically unsaturated compound containing an aromatic ring or a halogen, a polyfunctional acrylate or a polyfunctional methacrylate,
Addition of a photoinitiator to the copolymer solution completes the refractive index imaging element. However, R ₁ in the general formula is CH ₃ or H, and R ₂ is a chain compound or alicyclic compound group having 1 to 4 carbon atoms (hereinafter the same).

The fourth refractive index image forming material is formed by the following method. First, an ethylenically unsaturated compound containing silicon, an ethylenically unsaturated compound represented by the general formula R ₁ CH = CHCOOR ₂ , polyfunctional acrylate or polyfunctional methacrylate, and a thermal polymerization initiator is dissolved in a solvent, Is heated and stirred to prepare a copolymer solution. Next, after allowing the copolymer solution to cool to room temperature, an ethylenically unsaturated compound containing an aromatic ring or a halogen, a polyfunctional acrylate or a polyfunctional methacrylate, and a photopolymerization initiator to the copolymer solution. Upon addition, this completes the refractive index imaging element.

The fifth and fifth refractive index image-forming materials are a thermosetting copolymer containing an acrylate or methacrylate having a hydrogen group at the terminal in its structural unit, and an ethylene ring containing an aromatic ring or halogen. It is composed of a saturated compound, a polyfunctional acrylate or a polyfunctional methacrylate, and a photopolymerization initiator. The thermosetting copolymer is, for example, a substance containing chlorotrifluoroethylene, vinyltrimethylacetate, and an acrylate or methacrylate having a hydroxyl group at the terminal in its structural unit.

In the above refractive index image forming material, the ethylenically unsaturated compound containing an aromatic ring or halogen is, for example, allylcarbazole, methacryloyloxyethylcarbazole, acryloylethyloxycarbal, vinylcarbazole, vinylnaphthalene, It is any one of naphthyl acrylate, tribromophenyl acrylate, dibromophenyl acrylate, phenoxyethyl acrylate, or a mixture of any of these compounds.

Next, specific examples of the refractive index image forming material will be given. As a binder for the refractive index image forming material, an alicyclic or chain epoxy, an organically modified silicone, a copolymer having an ethylenically unsaturated compound having a hydroxyl group at its terminal in its constituent unit, or an ethylenically unsaturated compound containing silicon A copolymer having ## STR3 ## in its constituent unit is used. These binders have a reactive group and can be reacted by heating or by reflecting light, and excellent durability can be obtained.

Examples of the alicyclic or chain type epoxy include 3,4-
Epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, ERL-4299 (UCC), ERL-4092
(Manufactured by UCC), EHPE-3150 (Daicel UCB), Epolite 4000, Epolite 100MF, Epolite
80MF, Epolite 1600, Epolite 1500NP, Epolite
400P, Epolite 400E, Epolite M-1230 (Kyoeisha Oil and Fat Chemical Co., Ltd.), and a mixture or copolymer of the above compounds can be used.

As the organic modified silicone, acrylic modified silicone, methacrylic modified silicone, or epoxy modified silicone can be used. Further, a copolymer obtained by heating an ethylenically unsaturated compound containing silicon and an ethylenically unsaturated compound in a solvent to partially copolymerize them can be used as a binder. A polyfunctional acrylate or a polyfunctional methacrylate may be added as a monomer to be copolymerized. As the ethylenically unsaturated compound containing silicon, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, methacryloxypropyltris (trimethylsiloxy) silane, acryloxypropylmethylbis (trimethylsiloxy) silane, Acrylic modified silicone, methacrylic modified silicone, etc., and mixtures thereof can be used. Ethylenically unsaturated compounds include metal methacrylate, ethyl methacrylate, propyl methacrylate,
Isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, ethyl acrylate, n-butyl acrylate and the like and mixtures thereof can be used.

As the photoreactive monomer, a mixture of a polyfunctional acrylate or polyfunctional methacrylate and an ethylenically unsaturated monomer containing an aromatic ring or halogen is used. An ethylenically unsaturated monomer containing an aromatic ring or a halogen has a high refractive index, and by irradiation with light, the refractive index of the irradiated portion is polymerized and densified to increase the refractive index of the irradiated portion. Improve compared to. The polyfunctional acrylate or polyfunctional methacrylate improves photoreactivity,
Durability is improved by three-dimensionally crosslinking the polymer. Examples of ethylenically unsaturated monomers containing an aromatic ring or halogen include allylcarbazole, methacryloyloxyethylcarbazole, acryloylethyloxycarbazole, vinylcarbazole, vinylbenzylcarbazole, vinyloxyethylcarbazole, vinylnaphthalene, naphthyl acrylate, tribromo. Phenyl acrylate, dibromophenyl acrylate, phenoxyethyl acrylate, fluorene hydroxy acrylate, 2,2 '-(2-hydroxyethyl methacrylate) (2,3-dihydroxypropyl methacrylate) diphenate, 2,2'-(2-hydroxyethyl methacrylate) Hydrogen diphenate and mixtures of the above compounds can be used.

As the polyfunctional acrylate or polyfunctional methacrylate, trimethylolpropane triacrylate, neopaytyl glycol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, trimethylolpropane trimethacrylate, and a mixture of the above compounds can be used.

As the photopolymerization initiator, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, benzyl, benzoinisopropyl ether, BTTB (3,
Organic peroxides such as 3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone, benzoyl peroxide, di (t-butylperoxy) isophthalate, benzimidazole, 2- (o-chlorophenyl) Imidazoles such as 4,5-diphenylimidazole dimer, 2-mercaptobenzothiazole, P-diethylaminobenzophenone, 1H-1,
2,4-triazole-3-thiol, 4-methyl-4H-1,2,4-
Mixtures of combinations selected from compounds such as triazole-3-thiol, or iron-arene complexes such as pyrene-cyclopentadienyl-iron-hexafluoroantimonate, depending on the wavelength of light forming a refractive index image As a sensitizing dye, 4- (dicyanomethylene) -2-methyl-6
-(P-dimethylaminostyryl) -4H-pyran, 3,3'-carbonylbis (7-diethylaminocoumarin), 2,5-bis (4
-Diethylaminobenzylidene) cyclopentanone, 2,
6-bis (4-dimethylaminobenzylidene) cyclohexanone or the like may be used.

A thermosetting agent may be used to thermoset the thermosetting non-photoreactive component. For example, as a thermosetting agent when using a binder containing an epoxy group, hexamethylenediamine, trimethylhexamethylenediamine, diethylenetriamine, triethylenetetramine, tri (methylamino) hexane, diethylaminopropylamine, menthenediamine, isophorone Amino acids such as diamines, acid anhydrides such as methyltetrahydrophthalic anhydride and methylhexahydrophthalic anhydride, imidazoles such as 2-ethyl-4-methylimidazole and 2-phenylimidazole, etc., use a binder having a hydroxyl group. Coronate as the heat curing agent in the case
EH (Nippon Polyurethane), Coronate 2092 (Nippon Polyurethane), Duranate THA-100 (Asahi Kasei), Duranate TPA-100 (Asahi Kasei), Sumijour N3500 (Sumitomo Bayer Urethane), Takenate D-170N (Takeda Chemicals) Hardener, Nikarac MW030 (Sanwa Chemical), Nikarac MX-40 (Sanwa Chemical), Cymel 325
(Mitsui Toatsu Chemical Co., Ltd.) and other melamine-based curing agents.

These materials are prepared as a solution by dissolving them in a solvent if necessary. As the solvent, tetrahydrofuran, tetrahydropyran, acetone, methanol, diacetone alcohol, dichloromethane, dichloroethane, ethyl acetate, butyl acetate, dioxane, toluene,
The solvent that dissolves the material used is selected from the following. The prepared solution is filled or set by a method such as pouring, dropping, spin coating, knife coating, dipping and screen printing. When the solution contains a solvent, the solvent is removed by a method such as standing, heating, and reduced pressure.

The refractive index distribution is formed by irradiating the material with light. Depending on the refractive index distribution to be created, single-beam exposure,
Light irradiation methods such as multi-beam exposure and interference exposure are used. The light source is used by selecting from ultraviolet light, visible light, and infrared light according to the photosensitive wavelength range of the photopolymerization initiator or sensitizer added to the material. When performing interference exposure, a coherent light source is used.

In forming the refractive index distribution, in addition to the above-mentioned light irradiation step, heating may be carried out at 40 to 140 ° C., and the entire material may be irradiated with light. Through these steps, unreacted monomers can be reacted and cured, and unreacted photopolymerization initiators and sensitizers can be destroyed. As described above, the refractive index image-forming material of the present invention comprises, as a binder, an alicyclic or chain-type epoxy, acryl-modified silicone, methacryl-modified silicone, epoxy-modified silicone, and ethylenically unsaturated compound having a hydroxyl group at its terminal as a constituent unit. Since a reactive compound such as a copolymer contained therein is used, it can be crosslinked or polymerized by heating or light irradiation, and excellent durability can be obtained. (Q) Description of the seventeenth embodiment of the present invention The refractive index image forming material in each of the above-described embodiments is dissolved in a solvent, and then this solution is injected, drip method, spin coating method, knife coating method, Alternatively, it is supplied to an optical element or the like by either a dipping method.

Further, the refractive index image forming material supplied by the method is irradiated with a part of the light having a wavelength for forming a high refractive index image after removing the solvent. And, at least 40 ° C. before or after the high refractive index image is formed.
Either heating at ˜140 ° C. or UV irradiation is applied.

[0111]

As described above, according to the present invention, the end faces of the optical element are fixed so as to face each other with a space therebetween, the refractive index image forming material is supplied between the optical elements, and then at least one of the optical elements is provided. The material is irradiated with light through the light from the optical element, whereby a refractive index distribution having a condensing lens effect is formed. Since the optical elements are optically coupled by the self-alignment method as described above, the tolerance of alignment when initially fixing the optical elements is large, high accuracy is not required, and the coupling is facilitated. Further, since the light is condensed by the formed refractive index distribution, the coupling efficiency between the optical elements is improved.

Further, the above-mentioned refractive index image forming material can form a refractive index distribution only by irradiating light, and since the compound having reactivity is used as the binder, the binder compound is cured. Can be treated to improve durability. By using these bonding methods and the refractive index image forming material, the optical elements can be bonded with high efficiency with rough alignment.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an optical element coupling method according to a first exemplary embodiment of the present invention.

FIG. 2 is a cross-sectional view showing another mode of the optical element coupling method according to the first embodiment of the present invention.

FIG. 3 is a refractive index distribution diagram between optical elements coupled according to the first embodiment of the present invention.

FIG. 4 is a refractive index distribution diagram between optical elements having optical axis shifts, which are combined according to the first embodiment of the present invention.

FIG. 5 is a refractive index distribution diagram between optical elements coupled according to the first embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a combined state of the optical elements according to the first, third and fourth examples of the present invention.

FIG. 7 is a cross-sectional view showing a method for assembling an optical element according to a second embodiment of the present invention.

FIG. 8 is a cross-sectional view showing a method of coupling optical elements according to the third embodiment of the present invention.

FIG. 9 is a cross-sectional view showing an optical element coupling method according to fifth to ninth embodiments of the present invention.

FIG. 10 is a sectional view showing an optical element coupling method according to a tenth embodiment of the present invention.

[Explanation of symbols]

1, 9, 11 Support substrate (support) 2 V groove 3, 4, 23, 24 Optical fiber (optical element) 5, 25, 35 Refractive index image forming material (optical element coupling material) 6, 6A, 6B, 26 High refractive index image 7 Substrate 8 Semiconductor laser 20 Glass tube 21 Horizontal groove 22 Support substrate 30, 32 Glass plate 31 V groove 33 Optical fiber 34 Semiconductor laser 37 Fine movement stage

Front page continuation (72) Inventor Tetsuzo Yoshimura 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited

Claims (15)

[Claims] 1. A step of fixing the respective end faces of two optical elements (3, 4) with a space therebetween, and having a function as an adhesive agent for the optical elements and depending on the intensity of light in a specific wavelength band. Supplying a refractive index image forming material (5) which produces a refractive index distribution between the end faces of the two optical elements (3, 4), and at least one of the two optical elements (3, 4). Irradiating the refractive index image forming material (5) with light in the characteristic wavelength band from an end face to form a refractive index distribution (6) having a condensing lens effect. 2. Having a function as an adhesive for an optical element,
And a step of supplying a refractive index image forming material (5) having a high refractive index due to the intensity of light in a specific wavelength band onto the support (1), and an end face of each other through the refractive index image forming material (5) And placing two optical elements (3, 4) on the support (1) so that they face each other; and forming the refractive index image from at least one end surface of the two optical elements (3, 4). Irradiating the material (5) with light in the characteristic wavelength band to form a refractive index distribution (6) having a condensing lens effect, thereby forming an optical element coupling method. 3. Having a function as an adhesive for an optical element,
And a step of bringing a refractive index image forming material (5) having a high refractive index depending on the intensity of light in a specific wavelength band, onto the end face of the first optical element (3) on the support (11). And at least one of the end surface of the second optical element (4) facing the end surface of the first optical element (3) and the end surface of the first optical element (3) has the specific wavelength band A refractive index distribution (6
B) is formed, The optical element coupling method characterized by the above-mentioned. 4. A material which produces a refractive index distribution upon irradiation with light of a specific wavelength band, which is an alicyclic compound having an epoxy group or a chain compound, and an ethylenically unsaturated compound containing an aromatic ring or halogen. A refractive index image-forming material comprising a compound, a polyfunctional acrylate or a polyfunctional methacrylate, and a photopolymerization initiator. 5. A material which produces a refractive index distribution by irradiating light of a specific wavelength band, which comprises an organically modified silicon, an ethylenically unsaturated compound containing an aromatic ring or a halogen, a polyfunctional acrylate or a polyfunctional compound. With methacrylate,
A refractive index image-forming material comprising a photopolymerization initiator. 6. The refractive index image forming material according to claim 5, wherein the organic modified silicon is any one of acrylic modified silicon, methacrylic modified silicon, and epoxy modified silicon. 7. A material which produces a refractive index distribution by irradiating light of a specific wavelength band, wherein an ethylenically unsaturated compound containing silicon and a general formula R ₁ CH = CHCOOR ₂ (R ₁ is CH
₃ or H, R ₂ is a chain compound having 1 to 4 carbon atoms or an alicyclic compound group), an ethylenically unsaturated compound represented by the formula, and a thermal polymerization initiator are dissolved in a solvent, This is heated and stirred to prepare a copolymer solution, and after the copolymer solution is allowed to cool to room temperature, an ethylenically unsaturated compound containing an aromatic ring or a halogen, and a polyfunctional acrylate or a polyfunctional methacrylate. And a refractive index image forming material formed by adding a photopolymerization initiator to the copolymer solution. 8. A material which produces a refractive index distribution when irradiated with light of a specific wavelength band, wherein an ethylenically unsaturated compound containing silicon and a general formula R ₁ CH = CHCOOR ₂ (R ₁ is CH
₃ or H, R ₂ is a chain compound or alicyclic compound group having 1 to 4 carbon atoms), an ethylenically unsaturated compound, a polyfunctional acrylate or a polyfunctional methacrylate, and thermal polymerization An initiator and a solvent are dissolved in the solvent, and the solution is heated and stirred to prepare a copolymer solution, and the copolymer solution is allowed to cool to room temperature, and then an ethylenically unsaturated compound containing an aromatic ring or a halogen is added. , A polyfunctional acrylate or a polyfunctional methacrylate, and a refractive index image-forming material produced by adding a photopolymerization initiator to a copolymer solution thereof. 9. A thermosetting copolymer containing a acrylate or methacrylate having a hydrogen group at its terminal in its structural unit, which is a material which produces a refractive index distribution by irradiating light of a specific wavelength band. A refractive index image forming material comprising an ethylenically unsaturated compound containing a group ring or halogen, a polyfunctional acrylate or a polyfunctional methacrylate, and a photopolymerization initiator. 10. The thermosetting copolymer comprises chlorotrifluoroethylene, vinyl trimethylacetate, and a substance containing a hydroxyl group-terminated acrylate or methacrylate in its structural unit. Item 9. The refractive index image forming material according to item 9. 11. The ethylenically unsaturated compound containing an aromatic ring or halogen is allylcarbazole, methacryloyloxyethylcarbazole, acryloylethyloxycarbal, vinylcarbazole, vinylnaphthalene, naphthylacrylate, tribromophenylacrylate, dibromophenyl. 6. Any one of acrylate and phenoxyethyl acrylate, or a mixture of any one of them, 6.
Refractive index image forming material according to 7, 8 or 9. 12. A step of sandwiching the refractive index image forming material according to claim 4, 5, 6, 7, 8, 9, 10 or 11 between the end faces of two optical elements facing each other, and at least one of A step of irradiating the refractive index image forming material with light of a specific wavelength band from an end face of the optical element to form a refractive index distribution having a condensing lens effect. 13. The optical element comprises an optical fiber, a waveguide,
13. The optical element coupling method according to claim 1, wherein the optical element coupling method is any one of a semiconductor laser, a light emitting diode, a photodiode, and a semiconductor optical amplifier. 14. The optical element coupling method according to claim 1, further comprising the step of curing the refractive index image forming material by light irradiation or heating. 15. The distance between the coupled optical elements is set to 0.
It is 1 mm or more, Claims 1, 2, 3, 1
The optical element coupling method according to 2, 13, or 14.