JP6958063B2 - Manufacturing method of optical waveguide - Google Patents

Description

The present invention relates to a method for manufacturing an optical waveguide.

When optically connecting a silicon substrate on which an optical waveguide is formed and optical wiring such as an optical fiber, a method of interposing an optical waveguide between them is known. By interposing the optical waveguide, the light inlet / output point on the silicon substrate can be guided by the optical waveguide, so that the optical connection between the functional element and the optical wiring can be easily performed.

For example, in Patent Document 1, exuded light (evanescent light) is captured and optically connected between a polymer waveguide array formed on a polymer and a silicon waveguide array formed on a silicon chip. Structures that are optically connected by gratings are disclosed. Then, Patent Document 1 discloses that by combining a convex portion formed on a polymer and a concave portion formed on a silicon chip, both are self-aligned. As a result, the polymer waveguide array and the silicon waveguide array can be aligned with each other with high accuracy, so that the loss generated in the adiabatic coupling can be suppressed.

Japanese Unexamined Patent Publication No. 2014-81586

However, in the method described in Cited Document 1, it is necessary to form a recess on the silicon chip or a recess on the polymer. Therefore, the shape of the silicon chip or the polymer becomes complicated, and it is necessary to add a step of forming a concave portion or a convex portion in the manufacturing process thereof. As a result, there is a risk that the manufacturing cost will increase and the manufacturing yield will decrease.

From this point of view, when connecting an optical waveguide to an optical component, there is a demand for an optical waveguide capable of aligning both with high accuracy without complicating the structure.

In order to realize such highly accurate positioning, it is first necessary to accurately grasp the position of the core portion of the optical waveguide. Therefore, there is known a method of providing an alignment mark having high position accuracy with respect to the core portion and aligning the position of the optical waveguide with reference to the alignment mark. With this method, the position of the alignment mark with high visibility can be easily grasped, and the position of the core portion can be indirectly grasped accurately.

However, in order to enjoy such an effect, it is a prerequisite that the positional relationship between the alignment mark and the core portion is accurate. However, since the alignment mark and the core portion are often formed through different steps, it is difficult to accurately reproduce the positional relationship between them.

An object of the present invention is to provide a method for manufacturing an optical waveguide capable of efficiently manufacturing an optical waveguide having a core portion having a core portion having high position accuracy with respect to an alignment mark.

Such an object is achieved by the present invention of the following (1) to (7).
(1) a step of preparing a substrate having optical transparency, a mask provided on one surface side of the substrate, the masked substrate with a
A step of forming a clad layer having an average thickness of 3 to 200 times that of the mask on one surface side of the masked base material by applying the raw material liquid so as to cover the mask.
A step of forming a core forming layer on the side of the clad layer opposite to the masked base material side,
A step of irradiating the core forming layer with active radiation from the masked base material side to form a core portion on the core forming layer,
Have a,
The mask is
The first mask that overlaps the core part and
A second mask provided in a region other than the core portion and
A method for manufacturing an optical waveguide, which comprises.

(2) The method for producing an optical waveguide according to (1) above, wherein the core forming layer has a refractive index lowered by irradiation with the active radiation.

(3) The method for producing an optical waveguide according to (1) or (2) above, wherein the core cambium contains a compound having a functional group that can be dimerized by irradiation with active radiation.

(4) The method for manufacturing an optical waveguide according to any one of (1) to (3) above, wherein the mask contains a metal material.

(5) The method for producing an optical waveguide according to any one of (1) to (4) above, wherein the base material has a flexural modulus larger than that of the clad layer.

(6) The method for producing an optical waveguide according to any one of (1) to (5) above, wherein the average thickness of the clad layer is 2 to 50 μm.
(7) The method for producing an optical waveguide according to any one of (1) to (6) above, wherein the step of forming the core forming layer includes an operation of applying a raw material liquid.

According to the present invention, it is possible to efficiently manufacture an optical waveguide provided with a core portion having high position accuracy with respect to the alignment mark.

It is a figure for demonstrating embodiment of the manufacturing method of the optical waveguide of this invention. It is a figure for demonstrating embodiment of the manufacturing method of the optical waveguide of this invention. It is a figure for demonstrating the modification of the manufacturing method of the optical waveguide which concerns on embodiment shown in FIGS. 1 and 2. It is a top view which shows an example of the optical waveguide manufactured by the manufacturing method of the optical waveguide of this invention. It is sectional drawing of the optical waveguide shown in FIG. It is a top view which shows the modification 1 of the optical waveguide shown in FIG. It is a figure which shows the right end surface of the optical waveguide shown in FIG. It is a top view which shows the modification 2 of the optical waveguide shown in FIG. It is a perspective view which shows an example of the optical waveguide connector obtained by connecting the optical waveguide shown in FIGS. 1 and 2 and an optical interposer. It is a perspective view which shows the state of connecting the optical waveguide connector shown in FIG. 9 and an optical fiber. FIG. 9 is a cross-sectional view of the optical waveguide connector shown in FIG. It is a partially enlarged view of the optical waveguide connector shown in FIG. It is sectional drawing which shows the state of connecting the optical waveguide shown in FIGS. 1 and 2 and an optical interposer.

Hereinafter, the method for manufacturing the optical waveguide of the present invention will be described in detail based on the preferred embodiments shown in the accompanying drawings.

<Manufacturing method of optical waveguide>
First, an embodiment of the method for manufacturing an optical waveguide of the present invention will be described.

1 and 2 are diagrams for explaining an embodiment of the method for manufacturing an optical waveguide of the present invention, respectively. In the following description, the upper part of FIGS. 1 and 2 is referred to as "upper" and the lower part is referred to as "lower".

The method for manufacturing an optical waveguide according to the present embodiment includes a step of preparing a masked base material 7 having light transmission and forming a lower clad layer 11 on the upper surface side (one surface side) of the masked base material 7. The step of forming the core forming layer 130 on the upper surface side (the side opposite to the masked base material 7 side) of the lower clad layer 11 and the step of irradiating the core forming layer 130 with active radiation from the lower surface side to perform the core. The process includes a step of forming the core portion 14 and the side surface clad portion 15 on the forming layer 130 to obtain the core layer 13, and a step of forming the upper clad layer 12 on the upper surface side of the core layer 13.

[1] Step of Preparing Masked Base Material 7 First, as shown in FIG. 1A, a masked base material 7 having a light-transmitting base material 71 and a mask 72 is prepared.

The base material 71 is not particularly limited as long as it has light transmittance. Examples of the constituent material of the base material 71 include acrylic resin, methacrylic resin, polycarbonate, polystyrene, cyclic ether resin such as epoxy resin and oxetane resin, polyamide, polyimide, polybenzoxazole, polysilane, polysilazane, and the like. Silicone-based resin, fluorine-based resin, polyurethane, polyolefin-based resin, polybutadiene, polyisoprene, polychloroprene, polyester such as PET and PBT, polyethylene succinate, polysulfone, polyether, benzocyclobutene-based resin, norbornene-based resin, etc. In addition to various resin materials based on a component such as a cyclic olefin resin, various glass materials such as quartz glass, borosilicate glass, and soda lime glass can be mentioned. The resin material may be a composite material or a polymer alloy in which materials having different compositions are combined.

Of these, the constituent material of the base material 71 is preferably a glass material. As a result, the base material 71 has both excellent light transmission and sufficient rigidity. Therefore, when the core forming layer 130 is to be formed on the upper surface side of the base material 71, the core forming layer 130 having high flatness can be formed. Therefore, when the mask 72 is projected, the pattern of the mask 72 and the pattern of the mask 72 are formed. The consistency with the pattern in the projection area is improved. In addition, the shape accuracy of the core portion 14 and the side clad portion 15 formed in the core layer 13 can be particularly improved.

The shape of the base material 71 is, for example, a flat plate. As a result, the light transmittance in the thickness direction is increased, and the straightness of light is also increased. Therefore, when the core forming layer 130, which will be described later, is irradiated with active radiation from the base material 71 side, the irradiation pattern can be accurately controlled.

The thickness of the base material 71 is appropriately set according to the constituent materials of the base material 71, but is preferably about 0.01 to 5 mm, more preferably about 0.05 to 3 mm, and 0. It is more preferably about 10 to 1 mm. If the thickness is set within such a range, the base material 71 having both excellent light transmission and sufficient rigidity can be obtained.

The light transmittance of the base material 71 is preferably as high as possible, but the total light transmittance at a wavelength of 550 nm is preferably 85% or more, and more preferably 90% or more. As a result, the core portion 14 and the side surface clad portion 15 can be efficiently formed in a short time in the step described later.

Further, as the base material 71, one having a bending elastic modulus larger than that of the lower clad layer 11 described later is preferably used. With such a base material 71, even if the thickness of the base material 71 is reduced, the flatness of the masked base material 7 can be improved, so that the accuracy of the pattern of the mask 72 can also be improved. As a result, the accuracy of the pattern of the core portion 14 to be formed can be improved, and the optical waveguide 1 having high optical coupling efficiency with other optical components can be efficiently manufactured.

The flexural modulus of the base material 71 is preferably 110% or more, more preferably about 120 to 1000%, of the flexural modulus of the lower clad layer 11.

The flexural modulus is, for example, a measured value at 25 ° C. determined according to the method for determining the bending characteristics of plastic specified in JIS K 7171: 2016.

The mask 72 is provided on the upper surface of the base material 71 in a region corresponding to the pattern of the core portion 14 and the side surface clad portion 15 formed on the core forming layer 130. Specifically, the mask 72 may be provided in the region where the core portion 14 is to be formed, or the mask 72 may be provided in the region where the side clad portion 15 is to be formed.

Such a mask 72 is not particularly limited as long as it has a light shielding property. Specific examples thereof include various photomasks such as chrome masks, emulsion masks and film masks, and various stencil masks such as metal masks and silicon masks.

Further, the mask 72 may be a separate body from the base material 71, or may be formed on the upper surface of the base material 71. Of these, the mask 72 is preferably formed on the upper surface of the base material 71. Since such a mask 72 can be formed with high accuracy and relatively easily, it contributes to manufacturing an optical waveguide 1 provided with a core portion 14 having high dimensional accuracy at low cost.

The constituent material of the mask 72 formed by the film forming method is not particularly limited as long as it has a light-shielding property, but for example, a metal material such as chromium or a chromium alloy, nickel or a nickel alloy, chromium oxide, or oxidation. In addition to oxide materials such as nickel, various nitride materials, various carbide materials, and the like can be mentioned.

Of these, the mask 72 preferably contains a metal material. As a result, a mask 72 having a high light shielding property can be obtained even if it is thin, so that the optical waveguide 1 having a thinner thickness can be manufactured. Further, since the visibility of the mask 72 is improved with the high light shielding property, the visibility is improved when the mask 72 is used as an alignment mark as described later.

The thickness of the mask 72 is appropriately set according to the constituent materials of the mask 72, but is preferably about 20 to 2000 nm, more preferably about 50 to 500 nm. By setting the thickness of the mask 72 within the above range, it is possible to minimize the influence of the unevenness of the mask 72 on the core layer 13 while sufficiently ensuring the light shielding property of the mask 72.

The film forming method of the mask 72 is not particularly limited, and examples thereof include a vapor phase film forming method, a liquid phase film forming method, and a plating method.

[2] Step of Forming the Lower Clad Layer 11 Next, as shown in FIG. 1 (b), the lower clad layer 11 is formed on the upper surface of the masked base material 7.

The lower clad layer 11 can be formed by, for example, a method of attaching a film, a method of applying a raw material liquid, or the like. Of these, the method of applying the raw material liquid is preferably used. In this method, by applying the raw material liquid so as to cover the mask 72, it is possible to prevent the influence of the thickness of the mask 72 from affecting the upper surface of the lower clad layer 11. As a result, the core forming layer 130 formed in the step described later can be flattened, and the dimensional accuracy of the core portion 14 can be further improved.

The coating method is not particularly limited, and examples thereof include a doctor blade method, a spin coating method, a dipping method, a table coating method, a spray method, an applicator method, a curtain coating method, a die coating method, and an inkjet method.

The method for drying the liquid film formed by such a method is also not particularly limited, and for example, a method of heating the liquid film, placing it under reduced pressure, or spraying a dry gas is used.

Then, if necessary, a process of curing the dry film may be added.
Such a process is, for example, heat treatment, and the conditions thereof are a temperature of 50 to 230 ° C. and a temperature of about 1 minute to 3 hours. Further, the heat treatment may be performed in a plurality of times.

The average thickness of the lower clad layer 11 is not particularly limited, but is preferably about 2 to 50 μm, and more preferably about 5 to 40 μm. By setting the average thickness of the lower clad layer 11 within the above range, a sufficient separation distance between the core forming layer 130 and the mask 72 can be secured. As a result, the probability that the light propagating through the formed core portion 14 leaks to the mask 72 side can be sufficiently reduced, which contributes to the realization of the optical waveguide 1 having high propagation efficiency. At the same time, it is possible to suppress the influence of the unevenness of the mask 72 on the core layer 13. Further, it is possible to prevent the lower clad layer 11 from becoming too thick, prevent a decrease in the straightness of the active radiation, and prevent the optical waveguide 1 from becoming thicker.

The average thickness of the lower clad layer 11 means the average value of the measured values when the thickness of the lower clad layer 11 is measured at an arbitrary 10 points or more.

Further, although it depends on the constituent material of the mask 72, the average thickness of the lower clad layer 11 is preferably about 2 to 200 times the average thickness of the mask 72, and is preferably about 3 to 150 times. More preferred. As a result, the lower clad layer 11 can be sufficiently flattened, and the influence of the unevenness of the mask 72 on the core layer 13 can be suppressed. Further, it is possible to prevent the lower clad layer 11 from becoming too thick, prevent a decrease in the straightness of active radiation, and form a core portion 14 having high dimensional accuracy.

Further, considering the separation distance between the mask 72 and the core portion 14, the mask 72 is preferably provided on the lower surface side (opposite side of the core layer 13 side) of the lower clad layer 11. As a result, it is possible to take a manufacturing process in which the mask 72 is provided on another member and then brought into close contact with the lower clad layer 11 (forming the lower clad layer 11). Therefore, the dimensional accuracy of the mask 72 becomes particularly good, and the mask 72 can be easily manufactured. Further, by providing the clad layer between the core portion 14 and the mask 72, it becomes easy to control the difference in the refractive index from the core portion 14.

Further, the mask 72 is provided on at least one surface of the base material 71 (in the present embodiment, the upper surface of the base material 71). As a result, the shape retention of the mask 72 is improved. That is, by providing the mask 72 on the surface of the base material 71 having a relatively high rigidity, the pattern of the mask 72 can be easily held. Therefore, the dimensional accuracy of the mask 72 is improved, and it becomes easier to grasp the position and shape of the core portion 14 more accurately.

The mask 72 may be provided on the lower surface of the base material 71 instead of the upper surface, or may be provided inside.

[3] Step of Forming Core Forming Layer 130 Next, as shown in FIG. 1 (c), the core forming layer 130 is placed on the upper surface side (opposite side of the masked base material 7 side) of the lower clad layer 11. Form.

The core forming layer 130 has a characteristic (refractive index modulation ability) in which the refractive index changes when irradiated with active radiation such as light or ultraviolet rays. Therefore, when the active radiation is irradiated to a specific region of the core forming layer 130, a refractive index difference is formed between the irradiated region and the non-irradiated region. As a result, the region on the high refractive index side becomes the core portion 14, and the region on the low refractive index side becomes the side clad portion 15.

Examples of the principle of refractive index modulation include monomer diffusion, photobleaching, photoisomerization, photodimerization, and the like, and one or a combination of two or more of these is used.

Of these, in monomer diffusion, a layer made of a material in which a photopolymerizable monomer having a different refractive index from this polymer is dispersed in the polymer is partially irradiated with light to polymerize the photopolymerizable monomer. The core portion 14 and the side clad portion 15 are formed by causing a bias in the refractive index in the layer by causing the photopolymerizable monomer to move and unevenly distribute accordingly.

Examples of the material that causes such monomer diffusion include the photosensitive resin composition described in JP-A-2010-090328.

Further, in photobleaching, the molecular structure in the material is cleaved by irradiation with light, and the leaving group is separated from the main chain. As a result, the refractive index of the material is changed to form the core portion 14 and the side clad portion 15.

Examples of the material that causes photobleaching include the core film material described in JP-A-2009-145867.

Further, in photoisomerization and photodimerization, photoisomerization or photodimerization of a material occurs by irradiation with light, respectively. As a result, the refractive index of the material is changed to form the core portion 14 and the side clad portion 15.

Examples of the material that causes photoisomerization include norbornene-based resins described in JP-A-2005-164650.

Examples of the material that causes photodimerization include compounds having a functional group that can be dimerized by active radiation. That is, the core cambium 130 may contain a compound having a functional group that can be dimerized by irradiation with active radiation. Examples of such functional groups include N = N groups such as azobenzene group, azonaphthalene group, aromatic heterocyclic azo group, bisazo group and formazan group, maleimide group, inden group, coumarin group, cinnamate group and polyene. C = C groups such as groups, stilben groups, stilvasol groups, stilvazolium groups, cinnamoyl groups, cinnamyl groups, cinnamylidene groups, hemithioindigo groups, chalcone groups, anthryl groups, aromatic Schiff groups, aromatic hydrazone structures. Examples thereof include a C = O group such as a C = N group, a benzophenone group, an anthraquinone group and the like, an ester group such as an allyl ester group, an acylphenol structure and the like, and at least one of these is used.

Examples of the composition containing such a compound include the photosensitive resin composition described in JP-A-2011-105791.

Further, in the case of refractive index modulation based on the principles of photobleaching, photoisomerization and photodimerization, the amount of change in the refractive index can be adjusted according to the irradiation amount of the irradiated light (irradiation amount of radiation). By gradually changing the irradiation amount of light according to the irradiation position, it is possible to form an arbitrary refractive index distribution, for example, a refractive index distribution accompanied by a smooth change in the refractive index. Thereby, a graded index type refractive index distribution can be easily formed.

As a method of gradually changing the irradiation amount of light according to the irradiation position, for example, a method of using a multi-tone mask such as a gray tone mask or a halftone mask, a method of scanning a light beam having a distribution in light intensity, and a region. Examples thereof include a method of irradiating while changing the irradiation time or irradiation intensity for each.

Further, the core forming layer 130 can be formed by, for example, a method of attaching a film, a method of applying a raw material liquid, or the like. The coating method is appropriately selected from the above-mentioned methods.

[4] Step of irradiating the core forming layer 130 with the active radiation L Next, as shown in FIG. 2A, the core forming layer 130 is irradiated with the active radiation L from the lower surface side. As a result, the core portion 14 and the side surface clad portion 15 are formed on the core forming layer 130.

When the active radiation L is irradiated to the lower surface side, that is, through the masked base material 7, the core forming layer 130 is irradiated with the active radiation L via the mask 72. Therefore, the active radiation L is shielded in the region where the mask 72 is provided, while the active radiation L reaches the core forming layer 130 in the region where the mask 72 is not provided.

The active radiation L is appropriately selected according to the type of radiation to which the core forming layer 130 reacts in the above-mentioned refractive index modulation ability, and examples thereof include light such as visible light and electromagnetic waves such as infrared rays and ultraviolet rays. Be done.

In the present embodiment, the core forming layer 130 having a refractive index modulation ability that reduces the refractive index of the irradiation region will be described as an example. That is, the refractive index of the core forming layer 130 according to the present embodiment is lowered by irradiation with the active radiation L. Therefore, as shown in FIG. 2A, the mask 72 is provided in the region where the core portion 14 is to be formed. When the active radiation L is irradiated through such a mask 72, the refractive index is lowered in the irradiated region and the side clad portion 15 is formed. Further, since the region overlapping the mask 72 is a non-irradiated region, the core portion 14 is formed. As a result, as will be described later, the mask 72 can be used not only as a mask but also as an alignment mark indicating a pattern that matches the position and shape of the core portion 14.

The core forming layer 130 may have a refractive index modulation ability that increases the refractive index of the irradiated region. In that case, the mask 72 will be provided in the region where the side clad portion 15 is to be formed.

Then, if necessary, a process of curing the core forming layer 130 may be added.
Such a process is, for example, heat treatment, and the conditions thereof are a temperature of 50 to 230 ° C. and a temperature of about 1 minute to 3 hours. Further, the heat treatment may be performed in a plurality of times.

As described above, the core layer 13 including the core portion 14 and the side clad portion 15 is formed (see FIG. 2B).

The core portion 14 and the side clad portion 15 formed in this manner can have the same base polymer as the constituent material of the core portion 14 and the side clad portion 15. When the base polymers are the same as each other, it means that the structures of the main repeating units contained in the polymer having the highest compounding ratio in both constituent materials are the same as each other. As a result, the physical characteristics such as the coefficient of thermal expansion and the elastic modulus of the core portion 14 and the side clad portion 15 are approximated to each other. As a result, even when the environment in which the optical waveguide 1 is placed changes or the optical waveguide 1 is bent, the core portion 14 is deformed, the transmission efficiency in the core portion 14 is lowered, the core portion 14 and others are used. It is possible to suppress a decrease in the optical coupling efficiency with the optical component of the above. Further, there is an advantage that the core layer 13 can be easily manufactured and the dimensional accuracy of the core portion 14 can be easily improved.

Further, such a core portion 14 and a side clad portion 15 are simultaneously formed by light irradiation. Therefore, it is possible to prevent foreign matter from adhering to the interface between the core portion 14 and the side clad portion 15 and the formation of gaps. As a result, an increase in propagation loss due to the interface between the core portion 14 and the side clad portion 15 is suppressed, and an optical waveguide 1 having high propagation efficiency can be obtained.

[5] Step of Forming Upper Clad Layer 12 Next, the upper clad layer 12 is formed on the upper surface side of the core layer 13.

The upper clad layer 12 can be formed by, for example, a method of attaching a film, a method of applying a raw material liquid, or the like. Specifically, it can be performed in the same manner as the formation of the lower clad layer 11.

As described above, the optical waveguide 1 including the lower clad layer 11, the core layer 13, and the upper clad layer 12 is obtained (see FIG. 2C).

The upper clad layer 12 may be provided as needed or may be omitted. In that case, this step can also be omitted.

In such a manufacturing method, in principle, the core portion 14 that faithfully reflects the pattern of the mask 72 is formed. In other words, the pattern of the mask 72 substantially matches the pattern of the core portion 14. Therefore, the mask 72 can be a mark (alignment mark) for grasping the position and shape of the core portion 14 in addition to the mask's original function of controlling the irradiation region of active radiation.
In addition, "substantially matching" means that a deviation of about a manufacturing error is allowed.

Further, since the mask 72 has a light shielding property, it has high visibility in the optical waveguide 1.

That is, in principle, in the optical waveguide 1, the base material 71, the lower clad layer 11, the core layer 13 and the upper clad layer 12 each have relatively high light transmittance. Therefore, even if the core portion 14 is to be visually recognized, it may be difficult to visually recognize the core portion 14 due to its light transmittance.

On the other hand, since the optical waveguide 1 according to the present embodiment includes the mask 72, the mask 72 having a light shielding property exists in the background having high light transmission. Therefore, for example, the visibility of the mask 72 can be particularly enhanced based on the difference in light transmission.

Then, by easily grasping the position and shape of the mask 72, it is possible to indirectly and accurately grasp the position and shape of the core portion 14. That is, the mask 72 has high positional accuracy with respect to the core portion 14. This is because the core portion 14 is formed corresponding to the region of the mask 72 when the core portion 14 is manufactured, so that the position and shape of the core portion 14 inevitably correspond to the position and shape of the mask 72.

Therefore, the mask 72 can be used as an alignment mark for aligning the position of the core portion 14 with respect to other optical components. That is, the optical waveguide 1 includes a core portion 14 having high positional accuracy with respect to the alignment mark. By using the mask 72 as an alignment mark, the optical waveguide 1 and other optical components can be aligned more accurately, so that the optical coupling efficiency between the optical waveguide 1 and other optical components can be easily achieved. Can be enhanced to.

In addition, by using the mask 72 as an alignment mark, the shape and position of the core portion 14 in the optical waveguide 1 can be easily recognized, so that it is easy and accurate to identify the product type and attach the connector and the like. It can be carried out.

<Modified example of manufacturing method of optical waveguide>
Next, a modified example of the method for manufacturing the optical waveguide according to the embodiment will be described.

FIG. 3 is a diagram for explaining a modified example of the method for manufacturing the optical waveguide according to the embodiment shown in FIGS. 1 and 2. In the following description, the upper part of FIG. 3 is referred to as "upper" and the lower part is referred to as "lower".

Hereinafter, a modified example will be described with reference to FIG. 3, but in the following description, the differences from the embodiments shown in FIGS. 1 and 2 will be mainly described, and the description of the same matters will be omitted.

This modification is the same as the embodiment shown in FIGS. 1 and 2 except that the method of forming the core portion 14 and the side clad portion 15 is different.

That is, the method for manufacturing the optical waveguide according to this modification includes a step of preparing a masked base material 7 having light transmission, a step of forming a lower clad layer 11 on the upper surface side of the masked base material 7. A step of forming the core forming layer 130 on the upper surface side of the lower clad layer 11, a step of irradiating the core forming layer 130 with active radiation L from the lower surface side and removing unnecessary portions to obtain a core portion 14, and a core. It includes a step of forming a side clad portion 15 and an upper clad layer 12 so as to cover the portion 14.

[1] Step of Preparing Masked Base Material 7 First, as shown in FIG. 1A, a masked base material provided with a light-transmitting base material 71 and a mask 72 in the same manner as in the above embodiment. Prepare 7.

[2] Step of Forming the Lower Clad Layer 11 Next, as shown in FIG. 1 (b), the lower clad layer 11 is formed on the upper surface of the masked base material 7 in the same manner as in the above embodiment.

[3] Step of Forming Core Forming Layer 130 Next, as shown in FIG. 1 (c), the core forming layer 130 is formed on the upper surface side of the lower clad layer 11 in the same manner as in the above embodiment.

[4] Step of irradiating the core forming layer 130 with the active radiation L Next, as shown in FIG. 3A, the core forming layer 130 is irradiated with the active radiation L from the lower surface side. As a result, solubility in the developing solution is imparted to the irradiated region.

Next, the developer is brought into contact with the core forming layer 130. As a result, the portion (unnecessary portion) corresponding to the irradiation region in the core forming layer 130 is dissolved. As a result, the portion corresponding to the non-irradiated region remains. Then, if necessary, the remaining portion is heat-treated.

As described above, the core portion 14 (core layer 13) is obtained (see FIG. 3B). In the example of FIG. 3, the core forming layer 130 of the portion where the core portion 14 is to be formed remains, and the core portion 14 (core layer 13) is obtained.

The core cambium 130 may have the above-mentioned positive-type photosensitivity, but may also have a negative-type photosensitivity. In that case, the pattern of the mask 72 may be inverted according to the photosensitivity.

[5] Step of forming the side clad portion 15 and the upper clad layer 12 so as to cover the core portion 14 Next, a portion where the side clad portion 15 and the upper clad layer 12 are integrated so as to cover the core portion 14 is formed. Form (see FIG. 3 (c)).

The formation of such a portion can be performed by, for example, a method of pasting a film, a method of applying a raw material liquid, or the like, but it is particularly preferable to perform the formation of such a portion by a method of applying a raw material liquid. As a result, the upper surface of the upper clad layer 12 is flattened, and the optical waveguide 1 having a shape that is easy to handle can be obtained.

The formation of such a portion can be performed in the same manner as the formation of the lower clad layer 11.
Even in the above-mentioned modified examples, the same effect as that of the above-described embodiment can be obtained.

<Optical Waveguide>
Next, an example of the optical waveguide manufactured by the method for manufacturing the optical waveguide of the present invention will be described.

FIG. 4 is a plan view showing an example of an optical waveguide manufactured by the method for manufacturing an optical waveguide of the present invention. Further, FIG. 5 is a cross-sectional view of the optical waveguide shown in FIG.

The optical waveguide 1 shown in FIG. 4 has a long shape and a sheet shape. In this optical waveguide 1, an optical signal can be transmitted between one end and the other end in the longitudinal direction.

As shown in FIG. 5, such an optical waveguide 1 comprises a laminate in which a lower clad layer 11, a core layer 13, and an upper clad layer 12 are laminated in this order from the bottom, and a masked base material 7. I have. In the present specification, of the two main surfaces of the core layer 13 in FIG. 5, which are in a front-to-back relationship with each other, the lower surface is referred to as "lower surface 103" and the upper surface is also referred to as "upper surface 104".

As shown in FIG. 4, the core layer 13 includes eight elongated core portions 14 provided in parallel and side clad portions 15 adjacent to the side surfaces of each core portion 14. .. The core portion 14 is surrounded by a clad portion (side clad portion 15, lower clad layer 11 and upper clad layer 12), and light can be confined and propagated in the core portion 14. That is, these core portions 14 function as transmission lines for transmitting optical signals in the optical waveguide 1.

On the other hand, the upper clad layer 12 may not be laminated on the portion of the upper surface 104 of the core layer 13 near the left end surface 101 (hereinafter, this portion is referred to as the “upper left surface 105”). In this case, the upper left surface 105 is exposed, and the core portion 14 can be brought close to other optical components. Thereby, on the upper left surface 105, for example, an adibatic bond can be formed between the core portion 14 and the optical interposer 2. This adibatic bond refers to a bond that is optically connected via exuding light (evanescent light).

The refractive index distribution in the cross section of the core layer 13 may be any distribution. This refractive index distribution may be a so-called step index (SI) type distribution in which the refractive index changes discontinuously, but at least the so-called graded distribution in which the refractive index in the width direction of the core portion 14 continuously changes. An index (GI) type distribution is preferred. As a result, even if there is some manufacturing variation, it is less likely to affect the optical coupling loss, so that the optical transmission efficiency of the core portion 14 is improved regardless of the manufacturing conditions.

Further, the optical waveguide 1 and the core portion 14 formed therein may be linear or curved in a plan view, respectively. Further, the optical waveguide 1 and the core portion 14 formed therein may be branched or intersect in the middle, respectively.

The cross-sectional shape of the core portion 14 is not particularly limited, and may be, for example, a circle such as a perfect circle, an ellipse, or an oval, or a polygon such as a triangle, a quadrangle, a pentagon, or a hexagon. Since it has a rectangular shape, there is an advantage that the core portion 14 can be easily formed.

On the other hand, the waveguide mode of the core portion 14 may be a multi-mode, but is preferably a single mode. As a result, it is possible to bond with high efficiency by adibatic bonding using evanescent light. Further, an optical waveguide 1 capable of optical connection with good optical coupling efficiency to an optical component whose waveguide mode is a single mode can be obtained.

The width and height of the core portion 14 (thickness of the core layer 13) are not particularly limited, but are preferably about 1 to 15 μm, more preferably about 2 to 12 μm, and about 3 to 10 μm, respectively. It is more preferable to have it. As a result, it is possible to suppress a decrease in transmission efficiency. Further, by setting the width and height of the core portion 14 within the above range, it becomes easy to set the waveguide mode of the core portion 14 to the single mode.

Further, as shown in FIG. 4, when a plurality of core portions 14 are arranged in parallel, the width of the side clad portions 15 located between the core portions 14 is not particularly limited, but is about 0.5 to 250 μm. It is preferably about 1 to 200 μm, more preferably about 2 to 125 μm. As a result, it is possible to narrow the pitch of the core portions 14 while preventing the optical signals from being mixed (crosstalk) between the core portions 14.

The number of core portions 14 formed in the optical waveguide 1 is not particularly limited, but is preferably about 1 to 100.

Further, if necessary, the optical waveguide 1 may be multi-layered. Specifically, the core layer and the clad layer can be alternately laminated on the upper clad layer 12 shown in FIG. 5 to form a multi-layer.

Examples of the constituent material (main material) of the core layer 13 as described above include acrylic resin, methacrylic resin, polycarbonate, polystyrene, cyclic ether resin such as epoxy resin and oxetane resin, and polyamide resin. Polygonic resin, polybenzoxazole, polysilane, polysilazane, silicone resin, fluororesin, polyurethane, polyolefin resin, polybutadiene, polyisoprene, polychloroprene, polyester such as PET and PBT, polyethylene succinate, polysulfone, polyether In addition to various resin materials based on components such as cyclic olefin resins such as benzocyclobutene resins and norbornene resins, various glass materials such as quartz glass and borosilicate glass can be mentioned. The resin material may be a composite material or a polymer alloy in which materials having different compositions are combined.

Further, as the constituent material of the lower clad layer 11 and the upper clad layer 12, for example, the same material as the constituent material of the core layer 13 described above can be used, but in particular, a (meth) acrylic resin or an epoxy resin. , Silicone-based resin, polyimide-based resin, fluororesin, and polyolefin-based resin are preferably at least one selected from the group.

The optical waveguide 1 is preferably made of a resin material. As a result, the optical waveguide 1 becomes inexpensive, highly flexible and lightweight, and facilitates handling and mounting work.

Further, the optical waveguide 1 may include a cover layer (not shown) laminated on the upper surface of the upper clad layer 12.

Examples of the constituent material of the cover layer include polyethylene terephthalate (PET), polyolefins such as polyethylene and polypropylene, various resin materials such as polyimide and polyamide, and various glass materials such as quartz glass and borosilicate glass.

The average thickness of the cover layer is not particularly limited, but is preferably about 5 to 500 μm, and more preferably about 10 to 400 μm. As a result, the cover layer has an appropriate rigidity, so that the core layer 13 can be reliably supported and the core layer 13 and the upper clad layer 12 can be reliably protected from external forces and the external environment.
The cover layer may be provided as needed and may be omitted.

Further, any layer may be interposed between the masked base material 7 and the lower clad layer 11 and between the cover layer and the upper clad layer 12, respectively, if necessary.

On the other hand, the upper clad layer 12 laminated on the upper surface 104 of the core layer 13 does not necessarily have to be provided and may be omitted. However, by providing the upper clad layer 12, for example, when the end face of the optical waveguide 1 is connected to the optical fiber, the coupling efficiency with the optical fiber is improved, and the core portion 14 can be protected from an external force or an external environment. .. Therefore, the reliability of the optical waveguide 1 can be further improved.

Further, in the optical waveguide 1 shown in FIG. 5, as described above, the upper clad layer 12 is not laminated on the upper left surface 105 of the upper surface 104 of the core layer 13. That is, in the optical waveguide 1 shown in FIG. 5, the left end surface 121 of the upper clad layer 12 recedes to the right side of the left end surface 101 of the core layer 13. As a result, when another optical component is arranged on the upper left surface 105, interference between the upper clad layer 12 and the optical component is avoided, and the core layer 13 is exposed. Therefore, it becomes easy to arrange the optical waveguide 1 and the optical component, and it is possible to improve the connectivity between the optical waveguide 1 and the optical component while reliably protecting the core portion 14 by the upper clad layer 12 other than the upper left surface 105. can.

The upper clad layer 12 may be laminated so as to cover the entire upper surface 104 of the core layer 13.

Further, since the upper surface 104 of the core layer 13 is exposed, the core portion 14 is also exposed, so that the distance between the core portion 14 and the optical component can be shortened. As a result, the optical coupling efficiency between the two can be further increased.

Such an optical waveguide 1 includes a masked base material 7 as described above. Therefore, the mask 72 can be used as an alignment mark for aligning the position of the core portion 14 with respect to other optical components. As a result, the optical waveguide 1 can be aligned with other optical components more accurately, and the optical coupling efficiency with other optical components can be improved.

<Modification example 1 of optical waveguide>
Next, a modification 1 of the optical waveguide shown in FIG. 4 will be described.

FIG. 6 is a plan view showing a modification 1 of the optical waveguide shown in FIG. Further, FIG. 7 is a diagram showing a right end surface of the optical waveguide shown in FIG. Note that FIGS. 6 and 7 show only a part of the optical waveguide.

Hereinafter, the first modification will be described, but in the following description, items different from the optical waveguide shown in FIG. 4 will be mainly described, and the same items will be omitted.

The masked base material 7 included in the optical waveguide 1 shown in FIG. 6 is a mask provided in a region other than the above-mentioned mask 72 (first mask) provided in a region overlapping the core portion 14 in a plan view. 73 (second mask) is further provided.

Specifically, the mask 73 shown in FIG. 6 is provided on the right end surface 102 of the optical waveguide 1 in which one end of the core portion 14 is exposed. More specifically, the optical waveguide 1 shown in FIG. 6 has a rectangular shape in a plan view, but masks 73 are provided at both ends of a short side located on the right side. As a result, the two masks 73 and 73 are exposed on the right end surface 102 where the light entrance / exit surface of the core portion 14 is exposed, that is, the right end surface shown in FIG. As a result, for example, when only one of both ends of the core portion 14 has specifications suitable for light incident, or when the mask 73 has specifications suitable for light emission, one of them can be easily used. Can be a marker for identification. That is, the mask 73 can be used as an alignment mark. Therefore, an optical waveguide 1 that easily realizes a connection with high optical coupling efficiency can be obtained.

Further, in this modification, as shown in FIG. 6, the mask 73 can be visually recognized when the upper surface 104 of the core layer 13 is viewed in a plan view, while the right end surface 102 of the optical waveguide 1 is as shown in FIG. The mask 73 can be visually recognized even when the mask 73 is viewed in a plan view. Therefore, the degree of freedom for visually recognizing the mask 73 is high, and the connection work between the optical waveguide 1 and other optical components can be performed more easily.

The number of masks 73 is not particularly limited. For example, when a plurality of core portions 14 are arranged in parallel, the mask 73 may or may not be added accordingly.

Further, the shape of the mask 73 is not particularly limited. Although the mask 73 shown in FIG. 6 has a quadrangular shape, it may have a circular shape, a polygonal shape, or another shape.
In the above-described first modification, the same effect as that of the above-described embodiment can be obtained.

<Modification example 2 of optical waveguide>
Next, a modification 2 of the optical waveguide shown in FIG. 4 will be described.

FIG. 8 is a plan view showing a modification 2 of the optical waveguide shown in FIG. Note that FIG. 8 illustrates only a part of the optical waveguide.

Hereinafter, the modified example 2 will be described, but in the following description, items different from the modified example 1 will be mainly described, and the same items will be omitted.

The masked base material 7 included in the optical waveguide 1 shown in FIG. 8 is the same as the optical waveguide 1 shown in FIG. 6 except that the position and shape of the mask 73 are different.

The mask 73 shown in FIG. 8 is provided near an intermediate point in the longitudinal direction of the core portion 14. The position of the mask 73 is not particularly limited, and may be any other position.

On the other hand, the shape of the mask 73 shown in FIG. 8 has an annular shape. When the image of the annular mask is recognized, not only the outer edge but also the inner edge can be recognized as edge coordinates. Therefore, it is possible to acquire the position coordinates with higher accuracy, and the optical waveguide 1 and other optical components can be connected with higher accuracy by using the position coordinates. That is, the mask 73 can be used as an alignment mark.

The shape of the mask 73 is not particularly limited, and may be a shape other than the annular shape shown in FIG.
In the above-mentioned modification 2, the same effect as that of the modification 1 can be obtained.

<Optical waveguide connector>
Next, an example of the optical waveguide connector obtained by connecting the optical waveguide shown in FIGS. 1 and 2 and the optical interposer will be described.

FIG. 9 is a perspective view showing an example of an optical waveguide connector obtained by connecting the optical waveguide shown in FIGS. 1 and 2 and an optical interposer, and FIG. 10 is a perspective view of the optical waveguide connector shown in FIG. 9 and an optical fiber. 11 is a cross-sectional view of the optical waveguide connector shown in FIG. 9, and FIG. 12 is a partially enlarged view of the optical waveguide connector shown in FIG. Further, FIG. 13 is a cross-sectional view showing how the optical waveguide shown in FIGS. 1 and 2 and the optical interposer are connected. In the following description, for convenience of explanation, the upper part of FIGS. 11 and 12 will be referred to as “upper” and the lower part will be referred to as “lower”.

The optical waveguide connection 10 shown in FIG. 9 includes an optical waveguide 1, an optical connector 5 provided at the right end of the optical waveguide 1, an optical interposer 2 to be connected to the optical waveguide 1, a mounting substrate 3, and the like. have.

Further, as shown in FIG. 10, the optical waveguide 1 shown in FIG. 9 is connected to an optical fiber 9 having an optical connector 91. That is, the right end surface 102 of the optical waveguide 1 is an optical input / output surface for inputting / outputting an optical signal, and by fastening the optical connector 5 and the optical connector 91 to each other, the optical input / output surface of the optical fiber 9 and the optical Are combined.

On the other hand, the optical interposer 2 includes an interposer substrate 21, a light guide unit 22, a conductive unit 23, bumps 24, a semiconductor element 25, and a light emitting / receiving element 26.

The upper clad layer 12 is not laminated on the portion of the upper surface 104 of the core layer 13 of the optical waveguide 1 near the left end surface 101 (hereinafter, this portion is referred to as the “upper left surface 105”) (FIG. 12). reference). Then, as shown in FIG. 12, an optical interposer 2 is provided on the upper left surface 105 so as to be in contact with the optical interposer 2. As a result, an adibatic bond is formed between the core portion 14 and the optical interposer 2 on the upper left surface 105. This adibatic bond means that it is optically connected via exuding light (evanescent light). As a result, optical signals can be transmitted to each other between the optical waveguide 1 and the optical interposer 2.

In order to manufacture such an optical waveguide connection 10, as shown in FIG. 13, the center of the width of the core portion 14 of the optical waveguide 1 and the center of the width of the light guide portion 22 of the optical interposer 2 coincide with each other. Place both so that. As a result, the photocoupling efficiency can be increased. At this time, in the optical waveguide 1, since the visibility of the core portion 14 is indirectly enhanced by the mask 72, the optical waveguide 1 can be easily positioned. As a result, the accuracy of alignment is improved, and the optical coupling efficiency can be improved.

(Optical connector)
As shown in FIG. 11, the optical connector 5 includes a connector main body 51 and a through hole 50 formed in the connector main body 51.

The optical waveguide 1 is adhered to the inner wall surface of the through hole 50 via an adhesive or the like. As a result, the optical connector 5 is fixed to the end of the optical waveguide 1. The optical connector 5 is configured to engage, for example, an optical connector 91 as shown in FIG. As a result, the optical waveguide 1 to which the optical connector 5 is mounted and the optical fiber 9 to which the optical connector 91 is mounted can be optically connected.

The outer shape of the connector main body 51 is not particularly limited, and may be a shape conforming to a rectangular parallelepiped as shown in FIGS. 9 to 11 or any other shape.

The optical connector 5 may be provided as needed or may be omitted. In that case, it may be connected to the optical fiber 9 without passing through the optical connector 5, or may be connected to a light receiving / receiving element or an optical interposer (not shown).

(Mounting board)
The mounting board 3 is a board for mounting the optical waveguide 1, the optical connector 5, and the optical interposer 2. By using such a mounting substrate 3, the optical waveguide 1 and the optical interposer 2 can be stably held. At the same time, the mounting board 3 includes active components such as LSI (Large-Scale Integration), IC (Integrated Circuit), CPU (Central Processing Unit), RAM (Random Access Memory), capacitors, coils, resistors, diodes and the like. Electronic components such as passive components, light emitting diodes, laser diodes, and optical components such as light receiving sensors can be mixedly mounted. This makes it possible to construct a more sophisticated optical waveguide connector 10.

The mounting substrate 3 includes an insulating substrate 31 and a conductive layer 32 (electrical wiring).
Of these, as the insulating substrate 31, any substrate having insulation and rigidity suitable for handling can be used. Specific examples include various resin materials such as polyimide resins, polyamide resins, epoxy resins, various vinyl resins, and polyester resins such as polyethylene terephthalate resins. In addition, paper, glass cloth, resin film, etc. are used as the base material, and the base material is impregnated with resin materials such as phenol-based resin, polyester-based resin, epoxy-based resin, cyanate-based resin, polyimide-based resin, and fluorine-based resin. In addition to insulating substrates used for composite copper-clad laminates such as glass cloth / epoxy copper-clad laminates and glass non-woven fabrics / epoxy copper-clad laminates, polyetherimide resin substrates and poly Examples thereof include heat-resistant and thermoplastic organic rigid substrates such as ether ketone resin substrates and polysulfone resin substrates, and ceramic rigid substrates such as alumina substrates, aluminum nitride substrates, and silicon carbide substrates.

Further, the conductive layer 32 is provided inside or on the surface of the insulating substrate 31. Examples of the constituent material of the conductive layer 32 include simple metals such as copper, aluminum, nickel, chromium, zinc, tin, gold, and silver, or alloys containing these metal elements.

The mounting substrate 3 may be provided as needed, and may be omitted if, for example, only the connection between the optical waveguide 1 and the optical interposer 2 has sufficient rigidity.

(Optical interposer)
The optical interposer 2 includes an interposer substrate 21, a light guide unit 22, a conductive unit 23, bumps 24, a semiconductor element 25, and a light emitting / receiving element 26.

The interposer substrate 21 may be any substrate as long as the light guide portion 22 and the conductive portion 23 can be mixedly mounted. For example, the substrate, glass substrate, ceramic substrate, compound semiconductor substrate, etc. mentioned as the above-mentioned insulating substrate 31 may be used, but a silicon substrate (silicon wafer), an SOI (Silicon On Insulator) substrate, or a silicon carbide substrate is preferable. Used.

The light guide unit 22 optically connects the light emitting / receiving element 26 and the optical waveguide 1. That is, the light guide unit 22 is provided so as to extend from the vicinity of the light emitting / receiving element 26 to the region in contact with the optical waveguide 1.

The width of the light guide portion 22 is not particularly limited, but is preferably narrower than the width of the core portion 14 of the optical waveguide 1. Specifically, it is preferably about 0.1 to 3 μm, and more preferably about 0.2 to 2 μm. Since such a light guide portion 22 can be formed at a high density, it contributes to miniaturization of the optical interposer 2. In addition, good optical coupling efficiency with the optical waveguide 1 is realized.

The light guide unit 22 may include a branching unit for distributing an optical signal, a merging unit for merging waves, a resonator, and the like, if necessary.

Further, the light guide unit 22 may include a portion whose width gradually changes. For example, a portion (tapered shape portion) whose width gradually decreases toward one end in the longitudinal direction of the light guide portion 22 may be included. By including such a tapered portion, the optical coupling efficiency between the light guide portion 22 and the core portion 14 can be further improved.

Further, as described above, the light guide portion 22 is preferably arranged so that the center of the width coincides with the center of the width of the core portion 14. By arranging in this way, it becomes easy to secure the maximum area where both sides overlap in a plan view. As a result, the optical coupling efficiency between the optical waveguide 1 and the optical interposer 2 can be further increased.

The fact that the center of the width of the light guide portion 22 and the center of the width of the core portion 14 coincide with each other means that the misalignment is 20% or less of the width of the core portion 14.

Further, it is preferable that the optical axis of the light guide portion 22 and the optical axis of the core portion 14 are parallel to each other. By arranging in this way, it becomes easy to secure the maximum area where both sides overlap in a plan view. As a result, the optical coupling efficiency between the optical waveguide 1 and the optical interposer 2 can be further increased.

The fact that the optical axis of the light guide unit 22 and the optical axis of the core unit 14 are parallel to each other means a state in which the angle deviation is 1 ° or less.

The conductive portion 23 electrically connects the semiconductor element 25 or the light emitting / receiving element 26 with the bump 24. That is, the conductive portion 23 is provided so as to extend from the vicinity of the semiconductor element 25 and the light emitting / receiving element 26 to the bump 24. The constituent material of the conductive portion 23 can be selected from the same constituent materials as those of the conductive layer 32 described above.

The bump 24 is provided on the lower surface of the interposer substrate 21 and electrically and mechanically connects the optical interposer 2 and the mounting substrate 3. Examples of the bump 24 include gold bumps and solder bumps.

Examples of the semiconductor element 25 include a driver IC, a transimpedance amplifier (TIA), a limiting amplifier (LA), or an active combination IC, LSI, CPU, RAM, ROM, sensor element, or the like in which these elements are combined. Elements can be mentioned.

In addition, the optical interposer 2 may be equipped with a passive element such as a capacitor, a coil, a resistor, a diode, or a piezoelectric element.

The semiconductor element 25 is preferably mounted as a bare chip. As a result, the optical interposer 2 can be further miniaturized.

Examples of the light receiving / receiving element 26 include a light emitting diode, a light emitting element such as a laser diode, a light receiving element such as a photodiode, and a composite element obtained by combining these.

The mounting method of the semiconductor element 25 and the light emitting / receiving element 26 is not particularly limited, and a mounting method other than the illustrated face-down flip chip mounting may be used.

Further, the semiconductor element 25 and the light emitting / receiving element 26 do not have to be individual elements, and may be a composite element in which both are combined.

The optical waveguide connector 10 provided with the optical interposer 2 as described above is controlled by a control element such as an LSI mounted on the mounting substrate 3, and functions as an optical transceiver that transmits or receives an optical signal. That is, it is inserted between the control element and the optical fiber 9 and is responsible for electrical / optical conversion, thereby contributing to the construction of optical communication between chips, boards, and servers, for example.

<Electronic equipment>
As described above, the optical waveguide 10 as described above is highly reliable because the optical waveguide 1 and the optical interposer 2 are connected with high optical coupling efficiency. Therefore, by providing the optical waveguide connector 10, a highly reliable electronic device capable of performing high-quality optical communication can be obtained.

Examples of such electronic devices include electronic devices such as smartphones, tablet terminals, mobile phones, game machines, router devices, WDM (Wavelength Division Multiplex) devices, personal computers, televisions, and home servers. In any of these electronic devices, it is necessary to transmit a large amount of data at high speed between an arithmetic unit such as an LSI and a storage device such as a RAM. Therefore, when such an electronic device is provided with the optical waveguide connector 10, problems such as noise and signal deterioration peculiar to electrical wiring are eliminated, and a dramatic improvement in its performance can be expected.

Further, in the optical waveguide portion, the amount of heat generated is significantly reduced as compared with the electric wiring. Therefore, the power required for cooling can be reduced, and the power consumption of the entire electronic device can be reduced.

Although the method for manufacturing the optical waveguide of the present invention has been described above based on the illustrated embodiment, the present invention is not limited thereto.
For example, any step may be added to the embodiment.

1 Optical Waveguide 2 Optical Interposer 3 Mounting Board 5 Optical Connector 7 Masked Base Material 9 Optical Fiber 10 Optical Waveguide Connection 11 Lower Clad Layer 12 Upper Clad Layer 13 Core Layer 14 Core 15 Side Clad 21 Interposer Board 22 Conductor Optical part 23 Conductive part 24 Bump 25 Semiconductor element 26 Light emitting / receiving element 31 Insulating substrate 32 Conductive layer 50 Through hole 51 Connector body 71 Base material 72 Mask 73 Mask 91 Optical connector 101 Left end surface 102 Right end surface 103 Bottom surface 104 Top surface 105 Left top surface 121 Left end face 130 core forming layer L active radiation

Claims (7)

A step of preparing a substrate having optical transparency, a mask provided on one surface side of the substrate, the masked substrate with a
A step of forming a clad layer having an average thickness of 3 to 200 times that of the mask on one surface side of the masked base material by applying the raw material liquid so as to cover the mask.
A step of forming a core forming layer on the side of the clad layer opposite to the masked base material side,
A step of irradiating the core forming layer with active radiation from the masked base material side to form a core portion on the core forming layer,
Have a,
The mask is
The first mask that overlaps the core part and
A second mask provided in a region other than the core portion and
A method for manufacturing an optical waveguide, which comprises. The method for manufacturing an optical waveguide according to claim 1, wherein the core forming layer has a refractive index whose refractive index is lowered by irradiation with the active radiation. The method for producing an optical waveguide according to claim 1 or 2, wherein the core cambium contains a compound having a functional group that can be dimerized by irradiation with active radiation. The method for manufacturing an optical waveguide according to any one of claims 1 to 3, wherein the mask includes a metal material. The method for producing an optical waveguide according to any one of claims 1 to 4, wherein the base material has a flexural modulus larger than that of the clad layer. The method for manufacturing an optical waveguide according to any one of claims 1 to 5 , wherein the average thickness of the clad layer is 2 to 50 μm. The method for manufacturing an optical waveguide according to any one of claims 1 to 6, wherein the step of forming the core forming layer includes an operation of applying a raw material liquid.

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