JPS6017704A - Manufacture of optical waveguide - Google Patents

Abstract

PURPOSE:To obtain an optical waveguide of a large size and a high NA, which can be connected to an optical fiber of a large aperture, etc. by repeating a formation of a film-like membrane and a selective optical polymerization, laminating and forming a thin type optical waveguide, and obtaining an optical waveguide of a thick film. CONSTITUTION:The quantity of a cast solution is adjusted so that the film thickness becomes 60mum. Subsequently, gaseous nitrogen is allowed to flow for 150min by 100ml/ min in a state that a case vessel 10 is half closed up tightly, and thereafter, an MA vapor is allowed to flow for 30min, a solvent and a part of a monomer are evaporated, and a half solid film 17 is prepared. Subsequently, both horizontal and vertical end faces of a photomask plate 12 are allowed to adhere tightly to positioning L-shaped metallic fittings 14, and ultraviolet rays 16 are irradiated for 15min. As for a part 19 which is not masked, an optical polymerization is caused, and it is converted to a polymer. That is a core part 18 being a high refractive index layer, and a clad part 19 being a low refractive index layer are formed, and first of all, a thin type optical waveguide 20 of the first layer is formed. In the same way, the thin type optical waveguide is laminated to the third layer from the first layer, and a large-sized optical waveguide whose film thickness is 180mum can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of the Invention The present invention relates to a method of manufacturing an optical waveguide, and particularly to a method of manufacturing an optical waveguide for creating a large optical waveguide that can be connected to a large diameter optical fiber.

(b) Prior art and its problems Conventionally, in order to create an optical waveguide, a polymer optical waveguide has been obtained by a one-selective photopolymerization method. To explain an example, as shown in FIG. 1(a), a mask 2 having a width corresponding to the width of the optical waveguide to be created is placed on a film 1 formed by casting, and then Irradiate with ultraviolet light 3.

The part of the film 1 that is not shielded from light by the mask 2 undergoes photopolymerization due to light irradiation, changing its refractive index, and the part of the film 1 that is not shielded by the mask 2 undergoes photopolymerization. Since there is no refractive index, the refractive index is the same as that of the base material, and the core part 5
becomes. In the optical waveguide thus obtained, the refractive index difference -Δn between the cladding part 4 and the core part 5 is as shown in FIG.

The back side is slightly smaller than the front side. this is.

Phase separation between base material and monomer in the photopolymerization part.

The intensity of the ultraviolet light decreases as it approaches the back surface, as shown in Figure 1 (b).
This is because the distribution curve shown in ) is obtained.

As mentioned above, when the refractive index difference decreases near the back surface, light scattering and leakage increase at the interface between the core part 5 and cladding part 4 in this part, and the light confinement effect is weak, making it difficult to use as an optical waveguide. This has the disadvantage of increasing losses.

Note that although Fig. 1 shows the case of a 100 x 100 μm optical waveguide, as shown in Fig. 2 (a), a 200 x 20
When manufacturing an optical waveguide with a large diameter of 0 μm, the ultraviolet light distribution curve and refractive index difference distribution are as shown in Figure 2 (b) and (,).
As shown in FIG. 2, the values near the back surface become smaller as the film thickness increases, and the above-mentioned drawbacks become more apparent. Therefore, conventionally it has been impossible to manufacture a large (large diameter) optical waveguide with a high NA.

(c) Purpose of the Invention In view of the above, it is an object of the present invention to provide a method for manufacturing an optical waveguide that can manufacture a large-sized, high-NA optical waveguide that can be connected to a large-diameter optical fiber or the like.

B) Structure and Effects of the Invention In order to achieve the above object, the method for manufacturing an optical waveguide of the present invention comprises forming a first film-like film of a transparent photopolymerization solution whose refractive index changes when irradiated with ultraviolet light. A first thin light guide that selectively irradiates ultraviolet light only to a predetermined area of the surface to photopolymerize it, and the area that undergoes photopolymerization becomes a low refractive index layer and the area that does not undergo photopolymerization becomes a high refractive index layer. A wave path is formed, and a second film film similar to the first film film is laminated on this first thin optical waveguide, and ultraviolet light is selectively irradiated only to a predetermined region in the same manner as above. and photopolymerize.

forming a second thin optical waveguide on the first thin optical waveguide, and then in the same manner as the formation of the second thin optical waveguide,
A large thick-film optical waveguide is obtained by sequentially forming multiple layers of thin optical waveguides.

According to this invention, the formation of a film-like film and selective photopolymerization are repeated to form a thin optical waveguide in layers, thereby obtaining a thick optical waveguide.

Each thin optical waveguide has a substantially uniform refractive index difference, and therefore the refractive index difference is uniform throughout the entire optical waveguide, that is, from the front surface to the back surface. Therefore, it is possible to obtain an optical waveguide that is much larger and has a higher NA than the conventional optical waveguide with small waveguide loss. Furthermore, since the thin optical waveguide is not laminated by laminating, etc., there is no waveguide loss due to scattering and reflection between each layer, and there is no reduction in reliability due to peeling. Furthermore, since the thin optical waveguides can be laminated by repeating the same process, the manufacturing process can be easily automated.

(e) Description of examples The present invention will be explained in more detail with reference to Examples below.

3(a) and 4(a) are cross-sectional views showing one process of an embodiment of the present invention. In the drawings, a jig device used for manufacturing will be described. 1° is a casting container to hold the casting solution, 11 is a level to keep the casting solution in the casting container 10 horizontal, 12 is a mask plate having a Manuk pattern 16, and 14 is an L-shaped metal fitting for positioning the mask plate 12. , 15 is an ultraviolet exposure device that generates parallel ultraviolet rays 16.

When a large-sized optical waveguide is to be installed, first, the cast container 10 is preliminarily cleaned with, for example, methylene chloride CH2Cl2, and the positioning mold fitting 14, which has been preliminarily cleaned in the same manner, is placed inside the cast container 10. Next, a casting solution is put into the casting container 20. For the casting solution, for example, bispheno-/l/Z-based polycarbonate PCZ7 is used as the base material.
0f, methyl acrylate MA42m1. as monomer. Methylene chloride CHZC121000f as solvent, penzoin ethyl ether BZEE 2.1 as photosensitizer
f, 0.07 g of hydroquinone HQ as inhibitor
Use a blend of.

The amount of casting solution is adjusted so that the film thickness is 60 μm. Further, the liquid level is leveled by adjusting the spirit level 11.

Next, the cast container 10 is kept in a semi-sealed state, and tissocas is poured at 100*J/min for 150 minutes, and after that, MA vapor is passed for 30 minutes to evaporate a portion of the solvent and monomer to form a sheet-like semi-solid film 17. create.

Subsequently, both the horizontal and vertical end surfaces of the photomask plate 12 are brought into close contact with the positioning mold fittings 14, and the photomask board 12 is brought into close contact with the film 17 with the mask surface 16 facing down. When the mask plate 12 slightly slips on the film 17, the ultraviolet exposure device 15 is activated.

Irradiate with ultraviolet light 16 for 15 minutes. The portion 18 masked by the mask pattern 16 of the mask plate 12 is not irradiated with ultraviolet light, so photopolymerization does not occur and pcz and MA are separated, but the unmasked portion 19 undergoes photopolymerization. , polymerized. That is, the core portion 18 is a high refractive index layer.

A cladding portion 19, which is a low refractive index layer, is formed.

In this case, the ultraviolet light intensity distribution in the photopolymerized portion of the film 17 is attenuated inside the film, as shown in FIG. 6(b), because the film 17 is thick.

Not much attenuation occurs, and the refractive index difference distribution is also nearly flat as shown in FIG. 6(,).

As described above, the first layer of thin optical waveguide 20 is first formed.

Next, the mask plate 12 is removed, and as shown in FIG. 4, a casting solution is poured over the photopolymerized film 17 in the same manner as in the case of FIG. 6 above.

Adjust the cast solution lid so that the film thickness is 0 μm. Thereafter, the cast container 100 is semi-sealed, and a total of 100,181 puffs of nitrogen gas is flowed for 150 minutes, and after that, MA steam is flowed for 60 minutes to evaporate a portion of the solvent and monomer to create a sheet-like semi-solid film 21. .

Subsequently, the mask plate 12 whose horizontal and vertical end surfaces are brought into close contact with the two-positioning mold fittings 14 is brought into close contact with the film 21 with the mask pattern 13 facing down. When the mask plate 12 can be slightly slid on the film 21, the ultraviolet exposure device is activated to irradiate the film with ultraviolet light of 16'ft for 15 minutes. As a result, a portion 22 in which photopolymerization does not occur and a portion 23 in which photopolymerization occurs are formed in the film 21. The film 21 in this case also has an ultraviolet light intensity distribution and a refractive index difference distribution as shown in FIG.
) and (C), it is approximately flat.

In this way, the second thin waveguide 20 of the first layer is
A layered thin optical waveguide 24 is formed.

Next, the mask plate 12 is removed and a third layer of thin optical waveguide (thickness: 60 μm) is formed on the second layer of thin optical waveguide 24 in the same manner as the first and second layers. Form.

As described above, the thin optical waveguides are laminated from the first layer to the sixth layer to form a Daisei optical waveguide with a film thickness of 180 μm.

After completing the above exposure, after leaving it at room temperature for 30 minutes or more as a post-processing, each 10 cast containers were placed in a vacuum dryer (not shown).
Transfer to dry for about 10 hours.

In addition to this, the core portions 18, 22. ... unpolymerized monomers are removed. Next, the laminated film was peeled off from the cast container 10, barcoded with a low refractive index coating agent to a thickness of 10 μm on the front and back surfaces, and dried in a hot air dryer.
Dry at 9G'C for 5 hours.

A cladding layer 25 (see FIG. 5) on the upper and lower surfaces is formed. With the above steps, the fabrication of the large leading waveguide is completed.

FIG. 5(a) is a cross-sectional view of a large optical waveguide completed as described above, in which jl+, 18, 22.26 are the core part, 19, 25.27 are the cladding part, and 25 is the cladding layer. be. This completed 180×180 μm optical waveguide can be coupled to an optical fiber with a diameter of 200 μm. The refractive index difference distribution of this optical waveguide is approximately flat as shown in Figure 5(b), so there is no part where the refractive index difference is small at the interface between the core and cladding, and the light confinement effect is strong. , and scattering due to the phase separation of p c ′,< and MA is also reduced, so it is possible to increase the size (large diameter) while maintaining a high NA compared to conventional optical waveguides.

In the above embodiments, the case where the film was produced by a casting method was explained.

The membrane may be formed by other methods, such as centrifugal force using a spinner or the like.

Further, in the above embodiments, a mask plate is used for photopolymerization selection, but light may be selectively irradiated by scanning laser light without a mask plate.

Furthermore, in the above embodiment, a case where three layers of thin optical waveguides are laminated has been described, but the present invention is not limited to this, and a large optical waveguide can be manufactured by forming any multilayer of two or more layers. Needless to say, this applies when

Furthermore, according to the implementation of the present invention, each layer, as shown in FIG. +0.31. ...The width of the waveguide 34 can be changed by sequentially changing the mask pattern width for each layer, for example, and the thickness of each layer 30, 31°... is an optical waveguide 6 with a circular approximation
It is also possible to get 5.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating a conventional optical waveguide manufacturing method, and FIG. 1(a) is a cross-sectional view of the conventional optical waveguide. Figure 1 (b) is a diagram of the ultraviolet light intensity distribution within the optical waveguide during exposure, Figure 1 (0) is a diagram of the refractive index difference distribution in the depth direction of the optical waveguide, and Figure 2 is a diagram of the conventional manufacturing method. FIG. 2(a) is a cross-sectional view of the large optical waveguide, and FIG. 2(b) is the ultraviolet light intensity during exposure inside the large optical waveguide. Distribution map, FIG. 2(c) is a refractive index difference distribution map in the depth direction of the same large optical waveguide. 6 and 4 are diagrams showing one embodiment of the present invention, and FIGS. 6(a) and 4(a) are cross-sectional views showing one manufacturing process, and FIG. 6(b) is a sectional view showing one manufacturing process. and Fig. 4(b) are ultraviolet light intensity distribution maps in each process, Fig. 3(c) and Fig. 4(C).
are the refractive index difference distribution diagrams in the depth direction of the optical waveguide during each process,
FIG. 5 is a diagram showing a large-sized optical waveguide manufactured according to the above embodiment, and FIG. 5(a) is a cross-sectional view thereof, and FIG.
) is a refractive index difference distribution diagram in the depth direction, and FIG. 6 is a sectional view of another optical waveguide that can be manufactured by the present invention. 10: Cast container, 13: Mask pattern. 15: Ultraviolet exposure device, 16: Ultraviolet light. 17:21: Fillem, 18 ・ 22 ・
26: core part, 19, 23, 27: cladding part. 20/24: Thin optical waveguide. Patent Applicant Tateishi Electric Co., Ltd. Agent Patent Attorney Shigeru Nakamura Figure 2 (a) 1 B 1 (b) (C) <b> (C)

Claims (1)

[Claims] (1) Photopolymerization is carried out by selectively irradiating ultraviolet light only on a predetermined area on the surface of a first film-like film of a transparent photopolymerization solution whose refractive index changes when irradiated with ultraviolet light. A first thin optical waveguide is formed in which a region subjected to photopolymerization is a low refractive index layer and a region not subjected to photopolymerization is a high refractive index layer;
A second film-like film similar to the first film-like film is laminated on the thin guiding waveguide of the film, and in the same manner as above, ultraviolet light is selectively irradiated only to a predetermined region to photopolymerize the film. A second thin optical waveguide was formed on the thin optical waveguide, and multiple layers of thin optical waveguides were sequentially formed in the same manner as in the formation of the second thin optical waveguide to obtain a large thick-film leading waveguide. A method for manufacturing an optical waveguide.