JP4306212B2 - Optical waveguide core manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a fine pattern by transferring a mold, and a mold and a pulling jig used therefor. In particular, it can be used for manufacturing an optical waveguide used for optical interconnection or the like.
[0002]
[Prior art]
The mold making method for producing a fine pattern by transferring a mold is used for producing arts and crafts, parts for industrial products, etc. as a method for producing a large quantity at a low cost. These only required rough dimensional accuracy.
[0003]
In recent years, the advancement of optical communication technology has proved the superiority of light. In addition, with the speeding up of signals of LSIs and the like, research and development of techniques for replacing electrical signals with optical signals are being carried out. An optical waveguide is expected as the transmission medium.
[0004]
Polymer optical waveguides that have been developed in recent years can be formed in a large area, and are applied to optical interconnections on the order of 1 cm to 1 m. Also, an optical component is mounted on the surface of a waveguide layer by forming an optical path conversion mirror on the optical waveguide.
[0005]
As a method of manufacturing the polymer optical waveguide, the dry etching shown in FIG. 14 is used, and the clad material 2A is placed on the substrate 50 (a), the core 1A and the pattern mask 51 are placed (b), and dry etching is performed. By patterning the core 1A in the vertical direction (c), removing the pattern mask (d), and providing the clad material 3A (e), or the pattern exposure & patterning shown in FIG. Using the development, the clad material 2A is placed on the substrate 50 (a), the core material 1 is placed (b), the pattern is exposed with the exposure light 53 using an exposure mask (c), and the core 1A is developed. A method of manufacturing a polymer optical waveguide by patterning (d) and providing a clad material 3A (e) is generally used. In addition, as a method for forming the optical path conversion mirror, the method shown in FIG. 16 in which the optical path conversion mirror (c) is provided by performing machining (b) with a dicing saw on the end face of the polymer optical waveguide (a). is there.
[0006]
However, separately performing the manufacture of the waveguide and the processing of the optical path conversion mirror results in a complicated manufacturing process and high cost. Therefore, as a method for simultaneously producing the waveguide and the mirror, there is a method using a mold shown in FIG. 17 (Japanese Patent Laid-Open No. 2001-1554049). Here, a substrate 57 having a recess is produced (a), the core material 1 is applied and cured thereon (b), the core 1A other than the recess is removed (c), and the release layer 56 and the clad 2A are formed on the entire surface. (D), removed from the mold 57 (e), transferred entirely to another substrate 20 (f), and then clad 3A is formed on the entire surface (g).
[0007]
However, in order to remove the core 1A other than the recess after the core 1A is formed on the entire surface of the substrate 57 having the recess, a long etching process is required and the cost is increased.
[0008]
[Problems to be solved by the invention]
As described above, the conventional fine pattern manufacturing method as described above is not limited to the core of the optical waveguide, etc., and a method of manufacturing a fine pattern in a state that does not require correction, a mold used therefor, and pulling treatment. Ingredients were sought.
This invention is made | formed in view of the problem which concerns, and makes it a subject to provide the method of manufacturing a fine pattern easily and with high precision, the type | mold used for it, and a pulling jig.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, first, the invention of claim 1 is a method of manufacturing a core of an optical waveguide, which is a fine pattern, by transferring it using a mold. A substrate having a pattern recess, embedding a resin for a core material in the recess while adjusting the dimensions of the mold by an external force in a pulling direction, curing the core material, and further applying a substrate coated with a cladding resin. Repeatedly curing the cladding resin, and then removing the mold;
An optical waveguide core manufacturing method characterized by the following.
According to a second aspect of the present invention, there is provided a method of manufacturing a core of an optical waveguide, which is a fine pattern, by transferring using a mold, wherein the mold is a substantially flat plate and has a fine pattern of protrusions. Applying a resin for the cladding material to a certain thickness so as to cover the convex portion while adjusting the dimensions of the mold by an external force in the pulling direction, and stacking the substrates, and curing the resin for the cladding material Further, the present invention provides a method of manufacturing a core of an optical waveguide, wherein the mold is further removed, and then a resin for a core material is embedded in the concave pattern of the clad formed with the concave pattern and cured.
According to a third aspect of the present invention, there is provided a method of manufacturing a core of an optical waveguide, which is a fine pattern, by transferring it using a mold, wherein the mold is a substantially flat plate and has a fine pattern of protrusions. While the dimensions of the mold are adjusted by external force in the pulling direction, the substrate coated with the resin for the cladding material is stacked, the resin for the cladding material is cured, the mold is removed, and then the concave pattern is formed. A method of manufacturing a core of an optical waveguide, comprising: embedding a resin for a core material in the concave pattern of a clad formed with a core material and curing the resin.
[0013]
According to a fourth aspect of the present invention, there is provided the optical waveguide core manufacturing method according to any one of the first to third aspects, wherein the mold has a hook portion at an edge.
[0014]
The invention according to claim 5 is the method for manufacturing a core of an optical waveguide according to any one of claims 1 to 4, wherein the direction of pulling the mold includes at least two directions orthogonal to each other.
[0015]
The invention according to claim 6 is the method for manufacturing a core of an optical waveguide according to any one of claims 1 to 5, characterized in that a portion to be pulled of the mold has a distance from a region having the fine pattern. .
[0016]
According to a seventh aspect of the present invention, in the core of the optical waveguide according to any one of the first to sixth aspects, the length of the portion to be pulled of the mold is longer than the dimension of the region having the fine pattern. It is a manufacturing method.
[0017]
The invention of claim 8 is the method for manufacturing a core of an optical waveguide according to any one of claims 1 to 7, wherein the material of the mold is a resin.
[0018]
The invention of claim 9 is the method for producing a core of an optical waveguide according to claim 8, wherein the material of the mold is a silicone resin.
[0019]
A tenth aspect of the present invention is the method for manufacturing a core of an optical waveguide according to any one of the first to ninth aspects, wherein the tensile modulus of the mold material is 1 × 10 ⁸ Pa or less.
[0020]
The optical waveguide core according to any one of claims 1 to 10, wherein the product of the length of the part to be pulled and the thickness of the mold is 1 × 10 cm ² or less. It is a manufacturing method.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described in detail below.
[0025]
In the production of parts for arts and crafts and industrial products, which are general uses of the mold making method, dimensional accuracy is not so important. However, there are cases where precise dimensional accuracy is required in order to use the molding method for producing a fine pattern such as an optical waveguide. For example, a case where a large number of optical waveguides are formed and light input / output to / from them is performed collectively. On the other hand, when there are a small number of optical waveguides and optical input / output alignment is performed individually, the requirement for dimensional accuracy is reduced.
[0026]
When dimensional accuracy is required, the dimension can be adjusted by applying an external force 15 in the pulling direction to the mold and extending it (FIG. 1). This has the following three effects. For one, it is possible to correct the shrinkage due to curing shrinkage or temperature change of the mold itself. Secondly, the expansion and contraction accompanying the hardening of the fine pattern material (or optical waveguide material) produced based on the mold can be corrected in advance.
[0027]
Third, the dimensional change due to the use of the fine pattern to be produced can be corrected in advance. For example, when it is necessary to align the optical waveguide with the optical input / output component, and the position of the optical input / output component is expanded or contracted compared to the design value, the size of the optical waveguide can be adjusted.
[0028]
When forming a complicated and fine pattern such as an optical waveguide, even if the final shape is a multilayer, it is difficult to form it at once, and it is desirable to manufacture each layer with high accuracy. As the mold in that case, a structure 10 which is a substantially flat plate and has a convex portion or a concave portion which is a fine pattern 11 can be used. Examples of the overall shape include (a), (b), and (c) as shown in FIG. 2, but are not limited thereto.
[0029]
When the mold 10 has a concave portion, a convex pattern can be formed by embedding a resin or the like therein. For example, the core pattern 1A can be formed by embedding the core material 1 of the optical waveguide. When the mold 10 has a convex shape, a concave pattern can be formed by overlapping a resin or the like thereon. For example, the clad material 2 of the optical waveguide can be stacked to form a clad 2A having a depression corresponding to the core pattern. What is necessary is just to embed the core 1A in the hollow later.
[0030]
In order to apply an external force 15 in the pulling direction to the mold, it is desirable to have a hook 12 on the edge of the mold. As the shape of the hooking portion 12, various shapes can be used as shown in FIG. For example, the protrusion may be provided on the upper and lower sides, provided on the upper side (b), provided on the lower side (c), configured with a curve so that no stress is applied (d), and formed as a hole (e). However, it is not limited to these.
[0031]
Desirably, the direction of pulling the mold includes at least two orthogonal directions (FIG. 4). It is also possible to add an auxiliary pull (FIG. 5).
[0032]
The part 13 to be pulled of the mold is preferably at a distance 14 from the region 11 having a fine pattern. This is necessary to prevent the concentration of pulling stress on some patterns and to suppress abnormal deformation of the patterns to a small extent (FIG. 6). xx is preferably 0.1 times or more of y, and yy is preferably 0.1 times or more of x. Furthermore, xx is preferably 0.2 times or more of y, and yy is preferably 0.2 times or more of x. Furthermore, xx is desirably 0.5 times or more of y, and yy is desirably 0.5 times or more of x. As xx and yy are larger, stress concentration and pattern deformation are less likely to occur in the specific pattern, but the proportion of the fine pattern area in the entire mold is reduced, and the mold 10 and the apparatus are increased.
[0033]
In addition, the length of the portion 13 to be pulled is preferably longer than the dimension of the region 11 having a fine pattern (FIG. 7A). That is, it is desirable that X is larger than x and Y is larger than y.
At this time, it is also possible to effectively lengthen the portion 13 by using a plurality of shortly pulled portions 13 (FIG. 7B).
[0034]
Various resins can be used as the mold material. In particular, a silicone resin is preferable because of its excellent releasability.
[0035]
As the pulling jig 16, as shown in FIG. 8, a tool using a micrometer can be used for fine adjustment. However, it is not limited to this.
[0036]
In a normal pattern, the amount requiring correction is within about 1%. Moreover, the force applied stably with a jig etc. is about 1 kg. Assuming that the pulling force F, the cross-sectional area S, the elastic modulus E, and the elongation ΔL / L, there is a relationship of F / S = E · ΔL / L. In order to perform correction with a small force F of about 1 kg, the pulling elastic modulus E needs to be small, and the product S of the length of the portion to be pulled and the thickness of the mold needs to be small. Specifically, the pulling modulus may be 1 × 10 ⁸ Pa or less, and the product of the portion to be pulled and the thickness may be 10 cm ² or less.
[0037]
A specific process for transferring the mold shape will be described. First, the case of a mold having a recess will be described with reference to FIG. The mold 10 is prepared (FIG. 9A), set on the pulling jig 16, and the dimensions are set while checking with a length measuring machine or the like (FIG. 9B). The mold 10 may be provided with a length measurement mark. Next, the fine pattern material to be produced (for example, the core epoxy resin 1) is embedded in the recesses (FIG. 9C). Then, the fine pattern material is cured by ultraviolet irradiation or the like. Further, a substrate 20 (for example, a glass substrate) coated with the cladding epoxy resin 2 is stacked, and if necessary, alignment is performed here, and the cladding 2 is cured by ultraviolet irradiation or the like (FIG. 9D). When the mold 10 is pulled from the jig 16 and then peeled off from the glass substrate 20, the convex pattern (core 1A) is transferred onto the clad 2A on the glass substrate 20 side (FIG. 9E). Further, the optical waveguide 5 is completed by covering with the clad 3A (FIG. 9F).
[0038]
The case of a mold having a convex portion will be described with reference to FIG. The mold 10 is prepared (FIG. 10A), set on the pulling jig 16, and the dimensions are set while checking with a length measuring machine or the like (FIG. 10B). The mold may be provided with a mark for length measurement. Next, a fine pattern material (for example, an epoxy resin 2 for cladding) to be produced is applied to a certain thickness so as to cover the convex portion (FIG. 10C), and the substrate 20 (for example, a glass substrate) is further stacked. (FIG. 10 (d)). Or the board | substrate 20 which apply | coated the epoxy resin 2 for clad may be accumulated (FIG.10 (d)). If necessary, alignment is performed here, and the clad 2 is cured by ultraviolet irradiation or the like. When the mold 10 is pulled from the jig 16 and then the glass substrate 20 is peeled off, a concave pattern (core groove) is formed in the clad 2A on the glass substrate 20 side (FIG. 10E). Then, after the core material 1 is embedded in the concave pattern and cured by ultraviolet irradiation or the like (FIG. 10 (f)), the optical waveguide 5 is completed by covering with the cladding 3A (FIG. 10 (g)).
[0039]
The produced optical waveguide 5 may be used while attached to the substrate 20 or may be peeled off from the substrate 20 and used in a film state. Alternatively, the substrate 20 may be peeled off after being adhered to another object while attached to the substrate 20.
[0040]
Note that the above process is a standard one, and various variations are possible. For example, the timing for setting the mold 10 to the pulling jig 16 is applied after the application, the timing for setting the dimensions is applied after the application, or the timing for removing the mold 10 from the jig 16 is applied after the glass substrate 20 is peeled off. Is possible. The gist of the present invention is that the dimensions can be adjusted by pulling the mold, and can naturally be used for molds other than the optical waveguide.
[0041]
For example, the case of manufacturing a microlens will be described with reference to FIGS. A mold having a microlens-shaped concave portion is prepared as the fine pattern 11 (FIG. 11A), set on the pulling jig 16, and the dimensions are set while checking with a length measuring instrument (FIG. 11B). ). By pulling strongly in the optical axis direction of the lens, the focal length can be changed by increasing the thickness near the center of the lens. Then, the microlens 9A can be made by embedding the microlens material 9 and curing it by ultraviolet irradiation or the like (FIG. 11C).
[0042]
【Example】
<Example 1>
[Mold making 1]
An embodiment of the present invention will be described with reference to FIG. First, a plurality of waveguides having a height of 40 μm, a width of 20 μm to 150 μm, and a length of 54 mm are formed as a resist pattern 32 by applying, baking, exposing, and developing a thick film photoresist on the substrate 31 (glass). A convex pattern was formed (FIG. 12A). Next, the end portion was obliquely processed by laser processing (FIG. 12B). The fine pattern region 11 is about 60 mm square.
[0043]
Then, the mold frame 35 is set so that the hook portion 12 can be formed on the mold (FIG. 12C), and the substrate 10 having the recesses is manufactured by using the liquid silicone resin 34 (FIG. 12). (D) to (e)). The used silicone resin (GE Toshiba Silicone Co., Ltd., product name TSE3508) has a tensile modulus of about 1 × 10 ⁷ Pa (measured with Tensilon Universal Tester RTC-1250). The length of the portion 13 to be pulled was 70 mm, the distance 14 from the fine pattern region 11 was 30 mm, and the mold thickness was 2 mm. At this time, the length of the concave pattern was 53.6 mm.
[0044]
<Example 2>
[Optical waveguide 1]
Another embodiment will be described with reference to FIG. First, a substrate 10 (silicone resin) having a recess, which was manufactured by [Mold making 1], was prepared (FIG. 9A). And it attached to the pull jig | tool 16 and adjusted so that the length of a concave pattern might become a design value (54 mm) (FIG.9 (b)). And the ultraviolet curable epoxy resin was apply | coated as the core material 1 so that a recessed part might be covered, and the core material 1 other than a recessed part was scraped off with the spatula 8. FIG. By irradiating the entire surface with ultraviolet rays, the core material 1 was cured to form a core 1A (FIG. 9C).
[0045]
On the other hand, another substrate 20 (glass) was prepared, and the entire surface was spin-coated with an ultraviolet curable epoxy resin as the clad material 2 (not shown).
[0046]
In this state, the core 1A and the clad material 2 were brought into close contact with each other, and the clad material 2 was cured to form the clad 2A by irradiating ultraviolet rays from another substrate side (FIG. 9D).
[0047]
After peeling off the substrate 10 having the recesses (FIG. 9E), aluminum was deposited to a thickness of 0.2 μm on the oblique surface, and an ultraviolet curable epoxy resin (same as above) was applied to the entire surface as the clad material 3 and irradiated with ultraviolet rays. The optical waveguide 5 was completed (FIG. 9 (f)). The length of the core was 54 mm.
[0048]
<Example 3>
[Optical waveguide 2]
Another embodiment will be described with reference to FIG. First, a substrate 10 (silicone resin) having a recess was prepared by [Mold making 1] (FIG. 9A). And it attached to the pulling jig | tool 16 and adjusted so that the length of a concave pattern might become the target value (54.1 mm) according to the use (FIG.9 (b)). Then, an ultraviolet curable epoxy resin (same as above) was applied as the core material 1 so as to cover the concave portion, and the core material 1 other than the concave portion was scraped off with a spatula 8. By irradiating the entire surface with ultraviolet rays, the core material 1 was cured to form a core 1A (FIG. 9C).
[0049]
On the other hand, another substrate 20 (glass) was prepared, and the entire surface was spin-coated with an ultraviolet curable epoxy resin (same as above) as a clad material 2 (not shown).
[0050]
In this state, the core 1A and the clad material 2 were brought into close contact with each other, and the clad material 2 was cured to form the clad 2A by irradiating ultraviolet rays from another substrate side (FIG. 9D).
[0051]
After peeling the substrate 10 having the recesses (FIG. 9 (e)), a metal is deposited on the oblique surface, and an ultraviolet curable epoxy resin (same as above) is 30 μm as the cladding material 3 on the entire surface (based on the portion with the core). The optical waveguide 5 was completed by coating and UV irradiation (FIG. 9F). The length of the core was 54.1 mm.
[0052]
<Example 4>
[Mold making 2]
Still another embodiment of the present invention will be described with reference to FIG. First, a thick film photoresist (manufactured by Clariant Japan Co., Ltd., product name AZ PLP100) is coated on a substrate 31 (glass) at a thickness of 40 μm, and is baked, exposed and developed at 90 degrees for 30 minutes (developer is made by Clariant Japan Co., Ltd.) , Product name AZ 400K), a plurality of waveguide-shaped concave patterns having a height of 40 μm, a width of 20 μm to 150 μm, and a length of 54 mm were formed as the resist pattern 32 (FIG. 13A). Next, the end portion was obliquely processed by laser processing (FIG. 13B). The area of the fine pattern is about 60 mm square.
[0053]
Then, the mold frame 35 is set so that the hook 12 is formed on the mold (FIG. 13C), and the mold is taken using the liquid silicone resin 34 (product name TSE3508 manufactured by GE Toshiba Silicone Co., Ltd.). Then, a substrate 10 having a convex portion was produced (FIGS. 13D to 13E). The pulling elastic modulus of the used silicone resin is about 1 × 10 ⁷ Pa (measured with a Tensilon universal testing machine RTC-1250). The length of the pulling portion was 70 mm, the distance from the fine pattern region was 30 mm, and the mold thickness was 2 mm. At this time, the length of the convex pattern was 53.6 mm.
[0054]
<Example 5>
[Optical waveguide 3]
Another embodiment of the present invention will be described with reference to FIG. First, a mold 10 (silicone resin) having a convex portion was prepared using [optical waveguide 2] (FIG. 10A). Then, it is attached to the pulling jig 16 and converted from the target value (54.1 mm) according to the application and the shrinkage rate of the epoxy used (about 0.2%) so that the length of the convex pattern becomes 54.2 mm. (FIG. 10B).
[0055]
On the other hand, another substrate 20 (glass) was prepared, and the entire surface was spin-coated with an ultraviolet curable epoxy resin (same as above) as a clad material 2 (not shown).
[0056]
In this state, the mold 10 and the clad material 2 were brought into close contact with each other by irradiating ultraviolet rays from the side of another substrate, and the clad material 2 was cured to form a clad 2A (FIG. 10 (d)).
[0057]
After peeling off the mold 10 having projections (FIG. 10 (e)), metal (same as above) is vapor-deposited (same conditions as above) on the oblique surface, and UV curable epoxy resin (same as above) is used as the core material 1 to form recesses. It applied so that it might cover, and the spatula 8 scraped off the core materials 1 other than a recessed part. By irradiating the entire surface with ultraviolet rays, the core material 1 was cured to form a core 1A (FIG. 10 (f)).
[0058]
Further, an ultraviolet curable epoxy resin (same as above) was applied as a clad material 30 to a thickness of 30 μm and irradiated with ultraviolet rays to complete the optical waveguide 5 (FIG. 10G). The length of the core was 54.2 mm. When the optical waveguide was peeled from the glass substrate, the length of the core was 54.1 mm.
[0059]
【The invention's effect】
As can be understood from the above description, the present invention has the following effects.
[0060]
First, by applying a pulling force to the mold, it is possible to adjust dimensions and obtain a precise fine pattern to be obtained.
Second, the dimension adjustment function enables correction in consideration of expansion / contraction of the mold, expansion / contraction of the fine pattern produced from the mold, and expansion / contraction of the other party combined with the produced fine pattern. In particular, application to such an optical waveguide makes it possible to obtain an element with high connection efficiency.
[0061]
[Brief description of the drawings]
FIG. 1 is a conceptual diagram showing a method for producing a fine pattern of the present invention.
FIG. 2 is a plan view showing an example of an overall shape of a mold for producing a fine pattern according to the present invention.
FIG. 3 is a cross-sectional view showing an example of a hooked portion shape of a mold for producing a fine pattern according to the present invention.
FIG. 4 is a plan view showing an example of a pulling method to a mold for producing a fine pattern according to the present invention.
FIG. 5 is a plan view showing another example of the pulling method to the mold for producing a fine pattern according to the present invention.
FIG. 6 is a plan view showing the relationship between the size of the fine pattern region of the present invention and the distance to the portion to be pulled.
FIG. 7 is a plan view showing the relationship between the size of a fine pattern region and the length of a portion to be pulled according to the present invention.
FIG. 8 is a plan view showing an example of a pulling jig according to the present invention.
9 is a cross-sectional view showing an example of a method for producing a fine pattern of the present invention. FIG.
FIG. 10 is a cross-sectional view showing another example of the method for producing a fine pattern of the present invention.
FIG. 11 is a cross-sectional view showing another example of a method for producing a fine pattern of the present invention.
FIG. 12 is a cross-sectional view showing an example of a method for producing a mold for producing a fine pattern of the present invention.
FIG. 13 is a cross-sectional view showing another example of a method for producing a mold for producing a fine pattern according to the present invention.
FIG. 14 is a cross-sectional view showing an example of a conventional method for manufacturing an optical waveguide.
FIG. 15 is a cross-sectional view showing another example of a conventional method for manufacturing an optical waveguide.
FIG. 16 is a cross-sectional view showing an example of a conventional mirror manufacturing method.
FIG. 17 is a cross-sectional view showing another example of a conventional method for manufacturing an optical waveguide and a mirror.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Core material 1A ... Core 2 ... Cladding material

Claims (11)

In the method of manufacturing the core of the optical waveguide that is a fine pattern by transferring using a mold,
The mold is a flat plate and has a concave portion with a fine pattern, and the core material is embedded in the concave portion while the dimensions of the die are adjusted by an external force in the pulling direction, and the core material is cured. Further, the substrate coated with the cladding resin is further stacked to cure the cladding resin, and then the mold is removed,
A method for manufacturing a core of an optical waveguide, characterized in that : In the method of manufacturing the core of the optical waveguide that is a fine pattern by transferring using a mold,
The mold is substantially flat and has fine pattern protrusions, and the clad material resin is fixed to a certain thickness so as to cover the protrusions while adjusting the dimensions of the mold by an external force in the pulling direction. The clad material resin is hardened, and the mold is removed. After that, the core material resin is embedded in the concave pattern of the clad in which the concave pattern is formed. Curing,
A method for manufacturing a core of an optical waveguide, characterized in that : In the method of manufacturing the core of the optical waveguide that is a fine pattern by transferring using a mold,
The mold is a flat plate and has a fine pattern of protrusions, and the substrate coated with a resin for the cladding material is stacked while the dimensions of the mold are adjusted by an external force in the pulling direction. Curing the resin, further removing the mold, and then embedding and curing the resin for the core material in the concave pattern of the clad formed with the concave pattern,
A method for manufacturing a core of an optical waveguide, characterized in that : 4. The method of manufacturing a core of an optical waveguide according to claim 1, wherein the mold has a hook portion at an edge. 5. The method of manufacturing a core of an optical waveguide according to claim 1, wherein the direction of pulling the mold includes at least two directions orthogonal to each other. 6. The method of manufacturing a core of an optical waveguide according to claim 1, wherein a portion to be pulled of the mold has a distance from a region having the fine pattern. 7. The method of manufacturing a core of an optical waveguide according to claim 1, wherein a length of the part to be pulled of the mold is longer than a dimension of the region having the fine pattern. 8. The method of manufacturing a core of an optical waveguide according to claim 1, wherein the material of the mold is a resin. 9. The method of manufacturing an optical waveguide core according to claim 8, wherein the material of the mold is a silicone resin. The tensile modulus of the mold material is 1 × 10 ⁸ 10. The method for manufacturing a core of an optical waveguide according to claim 1, wherein the core is Pa or less. The product of the length of the part to be pulled and the thickness of the mold is 1 × 10 cm ² The method for manufacturing a core of an optical waveguide according to claim 1, wherein:

Images