JPH11109175A - Optical waveguide coupler and its forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical waveguide coupler capable of mounting an optical fiber to an optical waveguide with high precision, and a method capable of easily forming this optical waveguide coupler. SOLUTION: This optical waveguide coupler is provided with a common base 11, a V-groove 13 formed on the common base 11, a protruding or recessed optical waveguide forming part 15 formed on the common base 11 and having an end part (15a or 15b) opposed to one end of the V-groove 13, and a channel type optical waveguide 21 formed on the optical waveguide forming part 15. A method for forming this optical waveguide coupler comprises steps of forming the V-groove 13 and the optical waveguide forming part 15 on the common base 11 by use of pressing work; forming an optical waveguide layer-containing layer on the upper surface of the common base 11; dicing at least the optical waveguide layer-containing layer in the boundary between the V-groove 13 and the optical waveguide forming part 15 to form the optical waveguide, the optical waveguide end surface, and the V-groove end surface opposed to the optical waveguide end surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a structure of an optical waveguide coupler for an optical device and a method for forming the same.

[0002]

2. Description of the Related Art Conventionally, a structure of an optical waveguide coupler in an optical device is described in a literature (Reference: Proceedings of the 1995 Institute of Electronics, Information and Communication Engineers General Conference, C-213). Examination of Subdivided Si-V Grooves for Mounting Satoshi Mizuta). According to this optical waveguide coupler, the Si formed on the Si substrate
A groove for fixing the optical fiber is provided on the Si substrate so that there is no need to adjust the alignment between the optical waveguide made of the O ₂ thin film and the core of the optical fiber. If the optical fiber is fixed in this groove, the alignment of the optical axis is performed, and the mounting can be performed with higher precision. In order to form such a connection structure, at least a step of providing an optical waveguide layer on a Si substrate, a step of forming an optical waveguide by channelizing the optical waveguide layer, and an end face of the optical waveguide and an optical fiber And forming a groove for fixing the optical fiber in the Si substrate by etching.

[0003]

However, when an optical waveguide coupler is formed using the above-described forming method, it takes a long time to form the optical waveguide coupler, the number of steps is large, and mass productivity is low.

In addition, since the alignment of the optical axis between the optical fiber and the optical waveguide must be performed for each optical waveguide coupler to be formed, the forming operation is difficult.

For this reason, there has been a demand for an optical waveguide coupler capable of mounting an optical fiber on an optical waveguide with high accuracy, and a method for easily forming the optical waveguide coupler.

[0006]

According to the optical waveguide coupler of the present invention, a common substrate, a V-groove formed in the common substrate, and one end of the V-groove formed in the common substrate are provided. And a convex or concave optical waveguide forming portion having an end facing the optical waveguide and a channel optical waveguide formed in the optical waveguide forming portion.

[0007] V for fixing an optical fiber to a common substrate
Since the groove and the optical waveguide forming portion are formed, an optical waveguide can be easily formed by providing an optical waveguide layer on the optical waveguide forming portion. Further, only by fixing the optical fiber in the V-groove of the optical waveguide coupler, the core end face of the optical fiber and the optical waveguide end face face each other, and the optical axis is aligned. Therefore, the mounting of the optical fiber on the optical waveguide can be performed easily and with high accuracy.

Preferably, a common substrate of the optical waveguide coupler is made of crystallized glass, ceramic, plastic or glass. In order to press the common substrate, materials such as these suitable for press processing are used.

As the crystallized glass, for example, Milacron PP and Milacron PH manufactured by NGK Insulators, Ltd. are preferably used. As the ceramic, for example, zirconia may be used. As plastic, for example, P
It is preferable to use MMA (polymethyl methacrylate).
As the glass, for example, BK6 is preferably used.

Preferably, the channel type optical waveguide is formed of a multilayer film of a cladding layer and an optical waveguide layer. By providing the cladding layer around the optical waveguide layer, the effect of confining light in the optical waveguide layer can be improved.

Preferably, the cladding layer is made of Si.
And consists of O ₂ thin film layer, it is preferable a layer of a thin film that is a higher refractive index than the cladding layer by using the optical waveguide layer doped to SiO ₂ material. By adding the SiO ₂ such as Ti or Ge, it is possible to increase the refractive index than SiO ₂ is not added. Therefore, the optical waveguide layer becomes a layer having a higher refractive index than the cladding layer, and light can be confined in the optical waveguide layer.

Further, the channel type optical waveguide may be made of a polymer having a higher refractive index than that of the common substrate. The polymer is preferably polymethyl methacrylate. At this time, the common substrate has a role as a cladding layer. If the optical waveguide is formed of a polymer having a higher refractive index than the common substrate, light can be confined in the optical waveguide.

The channel type optical waveguide may be made of glass having a higher refractive index than the common substrate.

Preferably, the convex optical waveguide forming portion has a triangular, quadrangular, trapezoidal or semicircular cross section. The convex optical waveguide forming portion may be composed of only a substrate, or may be composed of a substrate and an optical waveguide layer formed on the substrate. This optical waveguide forming portion can be easily formed by press working. When the optical waveguide layer is formed only of the substrate, the optical waveguide layer is formed on the substrate after the press working, and the optical waveguide layer formed on the convex portion becomes the optical waveguide. In the optical waveguide forming portion composed of the substrate and the optical waveguide layer, the convex portion formed by press working has the substrate in the lower layer portion and the optical waveguide layer in the upper layer portion. Therefore, the upper layer portion of the convex portion functions as an optical waveguide.

Preferably, the concave optical waveguide forming section has a triangular, quadrangular, trapezoidal or semicircular cross section. This concave optical waveguide forming portion may also be composed of only the substrate, or may be composed of the substrate and the optical waveguide layer formed on the substrate. The concave portion can be easily formed by press working. Then, in the optical waveguide forming portion consisting only of the substrate, an optical waveguide layer is formed at least in the concave portion of the concave portion, and this optical waveguide layer becomes an optical waveguide. When the optical waveguide forming portion is formed by the substrate and the optical waveguide layer, the optical waveguide layer in the upper layer of the concave portion becomes the optical waveguide.

Preferably, an optical fiber is provided in the V-groove of the optical waveguide coupler according to the present invention, and a core end face of this fiber is opposed to a waveguide end face of the channel type optical waveguide. The area facing the core end face is preferably 50% or more of the total area of the core end face. The alignment between the core cross section of the optical fiber and the end face of the waveguide of the channel type optical waveguide is performed by previously positioning and forming the V-groove for providing the optical fiber and the optical waveguide forming portion where the optical waveguide is formed. The positions of the V-groove and the optical waveguide are determined by setting the dimensions of a mold used for press working. If the area of the region of the waveguide end face facing the core end face is at least 50% or more of the total area of the core end face, it is considered that the connection loss of light is small, and the optical fiber can be accurately transferred to the optical waveguide. It can be said that it can be implemented.

In forming this optical waveguide coupler, it is preferable that V.sub.
Forming a groove and an optical waveguide forming portion, forming an optical waveguide layer-containing layer on the upper surface of the common substrate, and dicing at least the optical waveguide layer-containing layer at the boundary between the V-groove and the optical waveguide forming portion. Preferably, the method further includes the step of forming an optical waveguide, an end face of the optical waveguide, and a V-groove end face facing the end face of the optical waveguide. By pressing, a V-groove for determining the position of the optical fiber and the optical waveguide and the optical waveguide forming portion can be formed at once on the common substrate. Next, after providing an optical waveguide layer-containing layer with a film thickness set by CVD or the like on the common substrate, a simple process of dicing the optical waveguide layer-containing layer at the boundary between the V-groove and the optical waveguide forming portion is performed. Thus, the optical waveguide can be formed above the optical waveguide forming portion, and a smooth waveguide end face can be formed. Therefore, the number of steps can be reduced, and the optical waveguide coupler can be formed by simple processing. In addition, since the dimensions of the press mold are set at the beginning, if press processing is performed using this mold, the position of the optical fiber and the optical waveguide will be required each time the same optical waveguide coupling part is formed. There is no need to make adjustments. Therefore, it is possible to save troublesome positioning.

Also, the common substrate is made of crystallized glass or ceramic, the optical waveguide layer-containing layer is made of a cladding layer made of a SiO ₂ thin film, and a material obtained by adding impurities to SiO ₂ is used to make the refractive index higher than that of the cladding layer. It is preferable to use a multi-layered film with an optical waveguide layer made of a thin film. The effect of confining light in the optical waveguide layer can be further improved by the cladding layer. As the ceramic used for the common substrate, a ceramic that can be pressed, such as zirconia, is used.

The common substrate may be made of crystallized glass or ceramic, and the optical waveguide layer-containing layer may be an optical waveguide layer made of a polymer having a higher refractive index than the common substrate. The polymer used at this time is preferably PMMA (polymethyl methacrylate) or the like.

Further, in forming the optical waveguide coupler, preferably, a step of forming an optical waveguide layer on the upper surface of the common substrate and a pressing process on the common substrate on which the optical waveguide layer is provided are performed. Forming the groove and the optical waveguide forming portion, dicing at least the optical waveguide layer at the boundary between the V-groove and the optical waveguide forming portion, and forming an end face of the optical waveguide and the optical waveguide; And forming a groove end face. When forming this optical waveguide coupler, press working may be performed after forming the optical waveguide layer on the common substrate. After the optical waveguide layer is deposited on the common substrate with a uniform film thickness, pressing is performed, so that there is no difference in the partial film thickness of the optical waveguide layer on the substrate. For this reason,
Further, it can be expected that the accuracy of alignment between the optical fiber and the optical waveguide is improved. Also in this forming method, the number of steps can be reduced as compared with the conventional method, and the processing in each step can be simplified. In addition, since the positions of the optical fiber and the optical waveguide are also determined when setting the dimensions of the press working mold, it is necessary to position each and form a V-groove when forming the same optical waveguide coupler. Is gone.

In the case where the optical waveguide coupler is formed by the above-described method, preferably, the common substrate is formed of glass, crystallized glass, or ceramic, and the optical waveguide layer has a higher refractive index than the common substrate. It is preferable to form the glass as a material. The common substrate and the optical waveguide layer are preferably made of the above-mentioned materials suitable for press working.

Further, the common substrate may be formed of plastic, and the optical waveguide layer may be formed of a material having a higher refractive index than the common substrate.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. It should be noted that the drawings are only schematically shown to the extent that the invention can be understood, and thus the invention is not limited to the illustrated examples. In the figure,
For the sake of simplicity, hatching (oblique lines) showing a cross section is omitted except for a part.

<First Embodiment> As a first embodiment, for example, an optical waveguide in which a single linear optical waveguide is provided on a common substrate and optical fibers are connected to both ends of the optical waveguide. The wave coupler will be described with reference to the drawings.
2 to 4 are diagrams schematically showing main steps of forming the optical waveguide coupler of the present invention, and FIGS. 2A to 2D are plan views of the optical waveguide coupler as viewed from above. Shown in FIG.
(A)-(D) is sectional drawing which shows the cut surface cut | disconnected along XX of FIG.2 (A)-(D). FIG. 4 (A)-
(D) is a cross-sectional view showing a cut surface taken along the line YY in FIGS. 2 (A) to (D).

This optical waveguide coupler is formed as follows.

First, the common substrate 11 is formed by pressing.
Then, a V-groove 13 and an optical waveguide forming portion 15 are formed.

In this embodiment, first, the V-groove 13 to which the optical fiber is fixed and the portion 15 where the optical waveguide is formed (referred to as an optical waveguide forming portion) so that the optical fiber and the optical waveguide are preferably connected. ) Are formed on the common substrate 11 in the same step. In this example, FIGS. 2A and 3A
As shown in FIG. 2, a convex linear optical waveguide forming portion 15 and V-grooves 13 respectively connected to both ends (ends 15a and 15b) of the straight line of the optical waveguide forming portion 15 are formed in the common substrate 11. Form.

It is necessary to connect the optical fiber and the optical waveguide so as to reduce the connection loss of light as much as possible. For this reason, the dimensions of the pressing mold are determined so that the optical fiber and the optical waveguide are provided at positions where the core end surface of the optical fiber overlaps the optical waveguide end surface by 50 to 100%. The final mold dimensions are determined by repeating the experiment. In this embodiment, the length L of the common substrate 11 in the direction along the straight line of the optical waveguide is 2 cm, the length M of the common substrate 11 in the direction of the width of the optical waveguide is 1 cm, V
The length N of the groove 13 is 5 mm, and the width O of the V groove 13 is 150 μm.
(See FIG. 2A.) The depth P of the V-groove 13 is set to 129 μ
m, the height Q from the bottom surface of the common substrate 11 to the upper side of the V groove 13 is 600 μm, and the height R from the bottom surface of the common substrate 11 to the lower side of the convex optical waveguide forming portion 15 is 500 μm (FIG. 3).
See (A). ), The height S of the optical waveguide forming portion 15 is 6 μm
(See FIG. 4A.), The width T of the optical waveguide forming portion 15 is set to 4
The dimensions of the pressing mold were determined so that the length was μm (see FIG. 3A) and the length U of the optical waveguide forming portion 15 was 1 cm (see FIG. 4A). In addition, crystallized glass was used as the material of the common substrate 11, and here, Milacron PP or Milacron PH manufactured by NGK Insulators, Ltd. was used. Further, in the press working, the material of the common substrate 11 is put into a mold and then molded by pressing (see FIGS. 2A, 3A and 4A).

Next, an optical waveguide layer-containing layer is formed on the upper surface of the common substrate.

In this embodiment, the optical waveguide layer containing layer 17
Is composed of a multilayer film including a cladding layer and an optical waveguide layer having a refractive index higher than that of the cladding layer by 1% (not shown). In this embodiment, in order to make the optical waveguide a single mode, the difference in the refractive index between the cladding layer and the optical waveguide layer is 1%.
I have to. The cladding layer is a SiO ₂ thin film, and the optical waveguide layer is a film in which Ge is mixed with SiO ₂ to increase the refractive index. A multilayer film, which is the optical waveguide layer-containing layer 17, is formed on the upper surface of the pressed common substrate 11 in a thickness of 4 μm by CV.
It is formed by a method D (see FIGS. 2B, 3B, and 4B).

Next, at the boundary between the V-groove and the optical waveguide forming portion,
At least the optical waveguide layer-containing layer is diced to form an optical waveguide and an end face of the optical waveguide, and a V facing the end face of the optical waveguide.
A groove end face is formed.

Here, the V-groove 13 and the optical waveguide forming portion 15
Dicing the optical waveguide layer containing layer 17 at the boundary with
In order to perform this dicing a little excessively, a groove 19 of about several tens μm is formed in the common substrate 11 below the optical waveguide layer containing layer 17. The width V of the groove 19 is 40 μm. The optical waveguide 21 and the optical waveguide end face 21a are formed by dicing.
2 (C), FIG. 3 (C) and FIG.
See (C). ). This optical waveguide 21 is a channel type optical waveguide.

With the above steps, an optical waveguide coupler can be formed.

Accordingly, the alignment between the optical fiber and the optical waveguide, the formation of the V-groove in the common substrate, and the formation of the optical waveguide forming portion in the common substrate can be performed in the same process. The number of steps for forming the optical waveguide coupler can be reduced, and the optical waveguide coupler can be formed by simple processing. In addition, since the dimensions of the press mold are set at the beginning, if press processing is performed using this mold, the position of the optical fiber and the optical waveguide will be required each time the same optical waveguide coupling part is formed. There is no need to make adjustments. Therefore, it is possible to save troublesome positioning.

An example of the structure of the optical waveguide coupler formed in the above steps will be described with reference to FIG. FIG. 1 shows the first
It is a schematic perspective view of the optical waveguide coupler of an embodiment.

This optical waveguide coupler includes a common substrate 11,
The V-groove 13 formed in the common substrate 11 and the common substrate 1
1, a convex optical waveguide forming portion 15 having an end (15a or 15b) facing one end of the V groove 13, and a channel optical waveguide 21 formed in the optical waveguide forming portion 15. With

[0037] The material of the common substrate 11 is a crystallized glass, channel optical waveguides 21, Yes constituted Te than a multilayer film of the cladding layer and the optical waveguide layer, the cladding layer of SiO ₂ thin film The optical waveguide layer is made of a thin film in which Ge is added to SiO ₂ to make the refractive index higher than that of the cladding layer by 1%. The convex optical waveguide forming portion 15
Has a rectangular cross section. The groove 19 is formed by dicing for forming the optical waveguide 21 and the end face of the optical waveguide.

Since the V groove 13 for fixing the optical fiber to the common substrate 11 and the optical waveguide forming portion 15 are formed, the optical waveguide layer containing layer 1 is formed on the optical waveguide forming portion 15.
By providing 7 (or the optical waveguide layer 31), the optical waveguide 21 can be easily formed. Further, only by fixing the optical fiber in the V-groove 13 of the optical waveguide coupler, the core end face of the optical fiber and the optical waveguide end face face each other, and the optical axis is aligned. Therefore, the mounting of the optical fiber on the optical waveguide can be performed easily and with high accuracy.

When an optical fiber 23 is connected to the optical waveguide coupler, a structure as shown in FIGS. 2D, 3D and 4D is obtained. The optical fiber 23 connected to the optical waveguide coupler of this embodiment is, for example,
The diameter is 125 μm and the diameter of the core 25 is 8 μm. Further, the fixing of the optical fiber 23 to the V-groove 13
Here, an epoxy resin is used as an adhesive.

The core end face 25a of the optical fiber 23 faces the optical waveguide end face 21a of the channel type optical waveguide 21, and the area of the optical waveguide end face 21a facing the core end face 25a is equal to the total area of the core end face 25a. 50% or more.

As a result, since the crystallized glass is used as the material of the common substrate, molding by press working can be performed with an error of 1 μm or less.

Further, the channel type optical waveguide has a structure in which the cladding layer is provided around the optical waveguide layer, so that the effect of confining light in the optical waveguide layer can be improved.

Further, the area of the region of the optical waveguide end face facing the core end face is at least 50% or more of the total area of the core end face. Accordingly, in the optical waveguide coupler of this embodiment, it is considered that the connection loss of light is small, and it can be said that the optical fiber can be mounted on the optical waveguide with high accuracy.

In the optical waveguide coupler according to this embodiment, the common substrate may be made of ceramic, plastic or glass which can be pressed. Also,
For the channel type optical waveguide, a polymer such as polymethyl methacrylate having a higher refractive index than the common substrate may be used.

The optical waveguide forming portion may be concave instead of convex. In this case, an optical waveguide layer is formed at least in the recess, and this optical waveguide layer becomes a channel-type optical waveguide. The sectional shape of the convex or concave optical waveguide forming portion may be triangular, quadrangular, trapezoidal, or semicircular.

<Second Embodiment> As a second embodiment, the optical waveguide coupler described in the first embodiment is identical to the optical waveguide coupler described in the first embodiment except that the cross-sectional shape of the optical waveguide forming portion is a concave quadrangle. An optical waveguide coupler having the same structure will be described with reference to FIG. FIG. 5 corresponds to FIG. 3 of the first embodiment,
It is a schematic sectional view in a main process stage.

Hereinafter, points different from the first embodiment will be described, and detailed description of the same points as the first embodiment will be omitted.

First, an optical waveguide layer is formed on the upper surface of the common substrate.

In this embodiment, glass is used as the material of the common substrate 11. The optical waveguide layer 31 is formed on the flat upper surface of the common substrate 11 with glass having a uniform thickness, for example, glass whose refractive index is higher than that of the common substrate 11 by changing the composition. (FIG. 5 (A)). This optical waveguide layer 31 is preferably formed using a sol-gel method or a sputtering method.

Next, the common substrate 11 provided with the optical waveguide layer 31 is pressed to form the V-groove 13 and the optical waveguide forming portion 15.

The optical waveguide forming section 15 has a concave quadrangular cross section. The press processing is performed by using the optical waveguide layer 31 and the V-groove 13 in the concave portion of the optical waveguide forming portion 15.
The dimensions are determined by conducting experiments in advance so that the core of the optical fiber to be fixed to the optical fiber is connected well. By this pressing, the V-groove 13 is formed in the common substrate 11 and the optical waveguide layer 31.
And the optical waveguide forming portion 15 are formed (FIG. 5B).

Next, as in the first embodiment, V
At least the optical waveguide layer 31 at the boundary between the groove 13 and the optical waveguide forming section 15 is diced to form the optical waveguide 21 and the optical waveguide end face, and the V-groove end face facing the optical waveguide end face.

By this dicing, a smooth optical waveguide end face is formed. Further, a groove 19 is formed in the common substrate 11.

When the optical waveguide coupler is formed by the above steps, and the optical fiber 23 is fixed to the V-groove 13 of the optical waveguide coupler with an epoxy resin or the like, a structure having a cross section as shown in FIG. Is obtained. Since the core 25 of the optical fiber and the end face of the optical waveguide are aligned by a press working die, an excellent connection with reduced optical connection loss is obtained.

If the optical waveguide coupler is formed by the above-described forming method, the optical waveguide layer is deposited on the common substrate with a uniform film thickness and then pressed, so that the optical waveguide layer is partially formed on the substrate. The difference in film thickness disappears. For this reason, it is expected that the positioning accuracy between the optical fiber and the optical waveguide is further improved.

Also in this forming method, the number of steps can be reduced as compared with the conventional method, and the processing in each step can be simplified. In addition, since the positions of the optical fiber and the optical waveguide are also determined when setting the dimensions of the press working mold, it is necessary to position each and form a V-groove when forming the same optical waveguide coupler. Is gone.

In the optical waveguide coupler of this embodiment, preferably, the common substrate may be formed of crystallized glass or ceramic. Further, the optical waveguide layer may be formed of glass whose refractive index is higher than that of the common substrate. These materials for the common substrate and the optical waveguide layer are suitable for press working.

Further, the common substrate may be formed of plastic, and the optical waveguide layer may be formed of a material having a higher refractive index than the common substrate.

The optical waveguide forming portion may be convex, and the cross section of the concave or convex shape may be triangular, square,
It may be trapezoidal or semicircular.

[0060]

As is apparent from the above description, according to the optical waveguide coupler of the present invention, the common substrate, the V-groove formed in the common substrate, and the common substrate are formed in the common substrate.
It is characterized by comprising a convex or concave optical waveguide forming portion having an end facing one end of the V-groove, and a channel optical waveguide formed in the optical waveguide forming portion.

V for fixing the optical fiber to the common substrate
Since the groove and the optical waveguide forming portion are formed, an optical waveguide can be easily formed by providing an optical waveguide layer on the optical waveguide forming portion. Further, only by fixing the optical fiber in the V-groove of the optical waveguide coupler, the core end face of the optical fiber and the optical waveguide end face face each other, and the optical axis is aligned. Therefore, the mounting of the optical fiber on the optical waveguide can be performed easily and with high accuracy.

In forming this optical waveguide coupler, a step of forming a V-groove and an optical waveguide forming portion on a common substrate by press working, and forming an optical waveguide layer-containing layer on the upper surface of the common substrate And dicing at least the optical waveguide layer-containing layer at the boundary between the V-groove and the optical waveguide forming portion to form an optical waveguide, an optical waveguide end face, and a V-groove end face facing the optical waveguide end face. And should be included.

By pressing, a V-groove for determining the positions of the optical fiber and the optical waveguide and the optical waveguide forming portion can be formed at once on the common substrate. Next, after providing an optical waveguide layer-containing layer with a film thickness set by CVD or the like on the common substrate, a simple process of dicing the optical waveguide layer-containing layer at the boundary between the V-groove and the optical waveguide forming portion is performed. Thus, the optical waveguide can be formed above the optical waveguide forming portion, and a smooth waveguide end face can be formed. Therefore, the number of steps can be reduced, and the optical waveguide coupler can be formed by simple processing. Moreover, since the dimensions of the press mold are set first, if press work is performed using this mold, when forming the same optical waveguide coupler,
It is not necessary to align the optical fiber and the optical waveguide each time. Therefore, it is possible to save troublesome positioning.

Therefore, an optical waveguide coupler capable of mounting an optical fiber on an optical waveguide with high precision, and this optical waveguide coupler can be formed easily and with a reduced number of steps. Therefore, improvement in mass productivity can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of an optical waveguide coupler for explaining a first embodiment.

FIG. 2 is a plan view of the optical waveguide coupler as viewed from above, and a schematic process diagram, for explaining the first embodiment;

FIG. 3 is a schematic process cross-sectional view (part 1) of the optical waveguide coupler provided for describing the first embodiment;

FIG. 4 is a schematic process cross-sectional view (part 2) of the optical waveguide coupler provided for describing the first embodiment;

FIG. 5 is a schematic process cross-sectional view of an optical waveguide coupler corresponding to FIG. 3 for explaining a second embodiment;

[Explanation of symbols]

 11: Common substrate 13: V-groove 15: Optical waveguide forming portion 15a, 15b: Straight end of optical waveguide forming portion 17: Optical waveguide layer containing layer 19: Groove 21: Optical waveguide, channel type optical waveguide 21a: Optical waveguide End face 23: Optical fiber 25: Core 25a: Core end face 31: Optical waveguide layer

Claims (19)

[Claims] 1. A common substrate and a V formed on the common substrate
A groove, a convex or concave optical waveguide forming portion formed in the common substrate and having an end facing one end of the V groove, and a channel optical waveguide formed in the optical waveguide forming portion. An optical waveguide coupler comprising: 2. The optical waveguide coupler according to claim 1, wherein the common substrate is made of crystallized glass. 3. The optical waveguide coupler according to claim 1, wherein the common substrate is made of ceramic. 4. The optical waveguide coupler according to claim 1, wherein the common substrate is made of plastic. 5. The optical waveguide coupler according to claim 1, wherein the common substrate is made of glass. 6. The optical waveguide coupler according to claim 1, wherein said channel type optical waveguide is constituted by a multilayer film of a cladding layer and an optical waveguide layer. 7. The optical waveguide coupler according to claim 6, wherein the cladding layer is a layer made of a SiO ₂ thin film, and the optical waveguide layer is made of a material obtained by adding an impurity to SiO ₂ , and is formed of a material that is more than the cladding layer. An optical waveguide coupler comprising a thin film layer whose refractive index is increased by at most 3%. 8. The optical waveguide coupler according to claim 1, wherein the channel type optical waveguide is made of a polymer having a refractive index higher by at most 3% than that of the common substrate. Optical waveguide coupler. 9. The optical waveguide coupler according to claim 8, wherein the polymer is polymethyl methacrylate. 10. The optical waveguide coupler according to claim 1, wherein the channel-type optical waveguide is made of glass having a refractive index higher by at most 3% than that of the common substrate. Optical waveguide coupler. 11. The optical waveguide coupler according to claim 1, wherein the convex optical waveguide forming section has a triangular, quadrangular, trapezoidal, or semicircular cross-sectional shape. 12. The optical waveguide coupler according to claim 1, wherein the concave optical waveguide forming section has a triangular, quadrangular, trapezoidal, or semicircular cross-sectional shape. 13. The optical waveguide coupler according to claim 1, further comprising: an optical fiber in the V-shaped groove, wherein a core cross section of the optical fiber faces an end face of the waveguide of the channel type optical waveguide. An optical waveguide coupler, wherein an area of a waveguide end face facing the core end face is 50% or more of a total area of the core end face. 14. A step of forming a V-groove and an optical waveguide forming portion on a common substrate by using a press process in forming an optical waveguide coupler, and forming an optical waveguide layer-containing layer on an upper surface of the common substrate. And dicing at least the optical waveguide layer-containing layer at the boundary between the V-groove and the optical waveguide forming portion to form an optical waveguide, an optical waveguide end surface, and a V-groove end surface facing the optical waveguide end surface. And forming the optical waveguide coupler. 15. The method of forming an optical waveguide coupler according to claim 14, wherein the common substrate is made of crystallized glass or ceramic, and the optical waveguide layer-containing layer is formed of a cladding layer made of a SiO ₂ thin film and SiO ₂ . A method for forming an optical waveguide coupler, comprising a multilayer film including an optical waveguide layer formed of a thin film having a refractive index higher than that of the cladding layer by at most 3% using a material to which impurities are added. . 16. The method for forming an optical waveguide coupler according to claim 14, wherein the common substrate is made of crystallized glass or ceramic, and the optical waveguide layer-containing layer has a refractive index of at most 3% that of the common substrate. An optical waveguide coupler forming method, wherein the optical waveguide layer is made of a high polymer. 17. A method of forming an optical waveguide coupler, comprising: forming an optical waveguide layer on an upper surface of a common substrate; and pressing the common substrate provided with the optical waveguide layer to form a V-groove. Forming an optical waveguide forming portion; dicing at least the optical waveguide layer at the boundary between the V-groove and the optical waveguide forming portion to form an end face of the optical waveguide and the optical waveguide, and a V-groove end facing the optical waveguide end face; Forming an optical waveguide coupler. 18. The method for forming an optical waveguide coupler according to claim 17, wherein the common substrate is formed of glass, crystallized glass, or ceramic, and the optical waveguide layer has a refractive index higher than that of the common substrate. A method of forming an optical waveguide coupler, comprising forming a glass whose material is increased by at most 3%. 19. The optical waveguide coupler forming method according to claim 17, wherein the common substrate is formed of plastic, and the refractive index of the optical waveguide layer is at most 3% higher than that of the common substrate. A method for forming an optical waveguide coupler, comprising: