JP4728857B2 - Optical coupler - Google Patents

Description

  The present invention relates to an optical coupler for optically coupling an optical element to a substrate with an optical transmission path including a substrate and an optical transmission path.

With the development of the information and communication society, communication devices are required to have advanced processing capabilities such as high speed and large capacity. In response to such needs, it has become important to increase the signal transmission speed inside communication equipment, and it has become difficult to further increase the speed of transmission using conventional electrical signals. . Therefore, in recent years, studies for realizing high-speed transmission using an optical signal instead of an electrical signal have been advanced.
In an optical transmission system using an optical signal, an optical transmission path is indispensable in addition to optical elements such as a light emitting element and a light receiving element, and each optical element is optically coupled to the optical transmission path. Since the optical signal is formed with high and low light intensity, it is indispensable to secure the light intensity in the optical transmission system.

  However, since an electric circuit board is necessarily required to mount the optical element, in the structure in which the optical element is optically coupled to the optical transmission line, the electric circuit board is provided between the optical element and the optical transmission line. Therefore, the optical element and the optical transmission line are separated from each other. In addition, wire bonding is generally used for mounting an optical element. However, when mounting by wire bonding, the optical element and the electric circuit board are separated by a bonding loop. As a result, there is a problem that sufficient light intensity cannot be secured between the optical element and the optical transmission line.

In order to ensure sufficient light intensity in the optical transmission system having the above structure, means for optically coupling between each optical element and the optical transmission path with high optical coupling efficiency is required. As an optical coupling means that realizes high optical coupling efficiency,
(1) Lens type in which a lens for condensing light is installed between the optical element and the optical transmission path. (2) An optical waveguide structure for propagating light is formed between the optical element and the optical transmission path. Conventionally, two types of optical transmission line types are known.
A typical example of a conventional lens-type optical coupling means is shown in FIGS. In the figure, means for optically coupling the light emitting element 101 and the optical transmission path 102 using the microlenses 103 and 104 is shown. The microlenses 103 and 104 are provided on the light emitting element 101 side and the optical transmission path 102 side, respectively. Provided. Although FIG. 10 shows an example in which the light emitting element 101 is used, the same optical coupling means can be used even for a light receiving element.

  In the example of the conventional lens-type optical coupling means shown in FIG. 12, microlenses having different characteristics are used to make parallel light between the two microlenses 103 and 104.

Another example of a conventional transmission line type optical coupling means is shown in FIG. 13 (Patent Document 4). FIG. 13 shows a means for optically coupling the light emitting element 101 and the optical transmission line 102 using the optical pin 121. Although an example using a light emitting element is shown here, the same optical coupling means can be used even for a light receiving element.
The optical pin 121 is formed by processing a fiber, and the optical pin 121 is attached to the end face 105 of the optical transmission path 102. The optical axis of the optical pin 121 coincides with the optical axis of the light emitting element 101 and is in a direction perpendicular to the optical axis of the optical transmission path 102. In this conventional example, optical coupling is performed at two locations between the light emitting element 101 and the optical pin 121 and between the optical pin 121 and the optical transmission path 102.

  FIG. 14 shows still another example of a conventional transmission line type optical coupling structure (Patent Document 5). In the drawing, means for optically coupling the light emitting element 101 and the optical transmission line 102 using a waveguide sheet 131 is shown. Although an example using a light emitting element is shown here, the same optical coupling means can be used even for a light receiving element.

The waveguide sheet 131 is formed by forming a waveguide 132 in the thickness direction of the sheet base material, and is provided between the light emitting element 101 and the optical transmission path 102 to realize optical coupling between them. Also in this conventional example, optical coupling is performed at two locations between the light emitting element 101 and the waveguide sheet 131 and between the waveguide sheet 131 and the optical transmission path 102.
Patent Publication 5-241044 Patent Publication 2001-185752 Patent Publication 2002-189137 Patent Publication 2004-85913 WO2003 / 032035

However, the conventional optical coupling means has the following problems. Although the conventional lens-type optical coupling means has an advantage that high coupling efficiency can be realized, there is a problem that two lenses and optical elements must be mounted with high accuracy.
In addition, when the resin is used between the optical element and the optical transmission line, it is necessary to select a lens having a greater lens effect as a lens used for optical coupling. However, there is a problem that the cost is high because a material with a very small radius of curvature and processed with high accuracy is required.

  If the resin between the optical element and the optical transmission path is not filled with resin, the range of lens materials that can provide the required lens effect is widened, but the optical signal propagates in the air between the optical element and the optical transmission path. Therefore, there is a problem that the optical signal is attenuated and deteriorated.

On the other hand, the conventional transmission line type optical coupling means can have a simpler structure than the conventional lens type optical coupling means, but it is generally reduced in terms of optical coupling efficiency. . Since the optical coupling waveguide structure used for optical coupling needs to be mounted so that the optical axis thereof matches the optical axis of the optical element and the optical axis of the optical transmission path, high mounting position accuracy is required.
Furthermore, if the distance between the optical element and the optical coupling waveguide structure is increased, the optical coupling effect is reduced, and therefore it is necessary to make the two as close as possible. However, it is difficult to make an optical element and the optical coupling waveguide structure close to each other and to easily control the mounting position.

In the conventional example using the optical pin 121 in FIG. 12 and the conventional example using the waveguide sheet 131 in FIG. 13, two optical couplings are required, and high-precision alignment is required for both mountings. . Furthermore, in the case of wire bonding, since it is necessary to secure a bonding loop, it is difficult to mount it at a position close to the optical element.
Accordingly, the present invention has been made to solve these problems, and an object thereof is to provide an optical coupler that facilitates optical coupling between an optical element and an optical transmission path and realizes high coupling efficiency. And

According to a first aspect of the present invention, there is provided an optical coupler for optically coupling an optical element to a substrate with an optical transmission path comprising a substrate and an optical transmission path having an end face that changes the optical axis in a direction orthogonal to the substrate. The first optical coupling waveguide structure comprising: a first optical coupling waveguide structure having an optical axis orthogonal to the optical axis of the optical transmission line; and a second optical coupling waveguide structure. Is attached to the optical element, and a part or all of the second optical coupling waveguide structure is located at a position on the substrate with the optical transmission path facing the end face by a predetermined distance. The optical coupler is mounted.

In the second aspect , only the cladding of the first optical coupling waveguide structure and the second optical coupling waveguide structure is attached to the optical element and the substrate with an optical transmission path, respectively. The first optical coupling waveguide structure and the core of the second optical coupling waveguide structure are formed integrally with each other.

In a third aspect , the core diameter of the first optical coupling waveguide structure on the light output side or the second optical coupling waveguide structure on the light output side is the second optical coupling waveguide structure on the light input side. Alternatively, the optical coupler is smaller than the core diameter of the first optical coupling waveguide structure.

In a fourth aspect , the core diameter of the first optical coupling waveguide structure on the optical output side or the second optical coupling waveguide structure on the optical output side is the second optical coupling waveguide structure on the optical input side. Or it is larger than the core diameter of the said 1st waveguide structure for optical couplings, It is an optical coupler characterized by the above-mentioned.

According to a fifth aspect of the present invention, in the optical coupler, the input end of the first optical coupling waveguide structure or the second optical coupling waveguide structure on the optical output side has a lens shape. It is.

According to a sixth aspect of the present invention, in the optical coupler, the output end of the first optical coupling waveguide structure or the second optical coupling waveguide structure on the optical input side has a lens shape. It is.

  As described above, according to the present invention, the first optical coupling waveguide structure and the second optical coupling waveguide structure are mounted in advance on the optical element and the substrate with the optical transmission path, respectively. In the optical coupling, it is only necessary to position the first optical coupling waveguide structure 1 and the second optical coupling waveguide structure 2, and it is possible to easily realize highly accurate positioning. .

  In addition, since the first optical coupling waveguide structure and the second optical coupling waveguide structure are separately mounted in advance on the optical element and the substrate with the optical transmission path, respectively, positional accuracy is improved. Therefore, the length of each waveguide structure can be easily adjusted without being limited to wire bonding. Therefore, the length is adjusted so that the end portions of the first optical coupling waveguide structure and the second optical coupling waveguide structure approach the optical element and the optical transmission line, respectively, at the time of optical coupling. By doing so, high coupling efficiency can be obtained.

  In addition, the fact that the first and second optical coupling waveguide structures are individually mounted on the optical element and the substrate with the optical transmission path, for example, in a batch state in a wafer state or a state before the substrate is cut out. Can be formed. Furthermore, after the waveguide structure is formed, an optical transmission system can be realized only by mounting the optical element and the substrate with the transmission path, so that the process may be the same as that for mounting an ordinary electronic component, which is excellent in mass productivity. There is.

Furthermore, as a material used for the optical coupler of the present invention comprising the first optical coupling waveguide structure and the second optical coupling waveguide structure, the materials conventionally used for the waveguide structure are Similar materials can be used, and the material selectivity is excellent.
When the core diameter of the optical coupling waveguide structure on the light output side is smaller than the core diameter of the optical coupling waveguide structure on the light input side with respect to the first and second optical coupling waveguide structures Can achieve high coupling efficiency without performing highly accurate positioning.

  Conversely, if the core diameter of the optical coupling waveguide structure on the optical input side is made smaller than the core diameter of the optical coupling waveguide structure on the optical output side, only the necessary mode light is removed by removing high frequency components. It is possible to focus on the light input side and realize high-quality light propagation.

  Furthermore, by forming the end portions of the first optical coupling waveguide structure and the second optical coupling waveguide structure in a lens shape, a lens effect can be realized at each of the end portions, The coupling efficiency can be increased.

  The configuration of the optical coupler in a preferred embodiment of the present invention will be described in detail with reference to the drawings. In addition, about each structural part which has the same function, the same code | symbol is attached | subjected and shown for simplification of illustration and description.

An optical coupler according to the present invention is an optical coupler for optically coupling an optical element to a substrate with an optical transmission path including a substrate and an optical transmission path, and an optical axis orthogonal to the optical axis of the optical transmission path. A waveguide structure for optical coupling having the above is mounted on at least the optical element.
A first embodiment of the optical coupler of the present invention will be described below with reference to FIG. The optical coupler of the present embodiment includes a first optical coupling waveguide structure formed on the optical element side and a second optical coupling waveguide structure formed on the substrate side with an optical transmission path. . The optical element and the optical transmission path are optically coupled by coupling the first optical coupling waveguide structure and the second optical coupling waveguide structure.

  FIG. 1 shows an embodiment in which a light emitting element 11 and an optical transmission path 13 provided on a substrate 12 with an optical transmission path are optically coupled. FIG. 1A shows the mounting of the light emitting element 11 on the substrate 12 with an optical transmission path. (B) shows a state before mounting, and a state after mounting. In this embodiment, an example in which the light emitting element 11 is mounted on the substrate 12 with an optical transmission path is shown, but the same applies to the case where another optical element such as a light receiving element is mounted.

As shown in FIG. 1B, the light emitting element 11 and the optical transmission line 13 are optically coupled so that their optical axes are orthogonal to each other. That is, the optical axis of the light emitting element 11 is set to the vertical direction in the drawing, and the optical axis of the optical transmission path 13 is set to the horizontal direction in the drawing. Then, the light in the optical axis direction of the light emitting element is propagated through the optical transmission line 13 by changing the direction in the horizontal direction at the end face 14 of the optical transmission line 13.
A first optical coupling waveguide structure 1 and a second optical coupling waveguide structure 2 are formed on the light emitting element 11 and the substrate 12 with an optical transmission path, respectively. The optical coupler 10 of the present embodiment includes: The first optical coupling waveguide structure 1 and the second optical coupling waveguide structure 2 are configured.

  The first optical coupling waveguide structure 1 and the second optical coupling waveguide structure 2 are respectively formed in the light emitting element before the light emitting element 11 and the optical transmission line 13 shown in FIG. 11 and a substrate 12 with an optical transmission path are mounted in advance. That is, the first optical coupling waveguide structure 1 is individually attached to the light emitting element 11, and the second optical coupling waveguide structure 2 is also individually attached to the substrate 12 with an optical transmission path.

  As described above, since the first optical coupling waveguide structure 1 and the second optical coupling waveguide structure 2 are individually attached to the light emitting element 11 and the substrate 12 with an optical transmission path, the light emitting element 11 And the first optical coupling waveguide structure 1 and the optical transmission line 13 and the second optical coupling waveguide structure 2 can both be positioned with high accuracy and easily.

  As shown in FIG. 1B, the first optical coupling waveguide structure 1 and the second optical coupling waveguide structure 2 mounted in advance on the light emitting element 11 and the substrate with optical transmission path 12 respectively. By coupling, the light emitting element 11 and the optical transmission line 13 are optically coupled. In this coupling, only the positioning of the first optical coupling waveguide structure 1 and the second optical coupling waveguide structure 2 may be performed, and the positioning can be performed with high accuracy and easily.

  As shown in FIG. 1B, the coupling portion between the first optical coupling waveguide structure 1 and the second optical coupling waveguide structure 2 is covered with a sealing resin 15. As the sealing resin 15, it is preferable to use a resin having a refractive index similar to that of the cores 1 a and 2 a of each optical coupling waveguide structure. As a result, it is possible to avoid a reduction in coupling efficiency at the coupling surface between the first optical coupling waveguide structure 1 and the second optical coupling waveguide structure 2.

As described above, the optical coupler 10 of the present embodiment has the first optical coupling waveguide structure 1 and the second optical coupling waveguide structure 2 provided in advance on the light emitting element 11 and the substrate 12 with an optical transmission path, respectively. By attaching the first optical coupling waveguide structure 1 to the second optical coupling waveguide structure 1, it is only necessary to position the first optical coupling waveguide structure 1 and the second optical coupling waveguide structure 2 at the time of optical coupling. It becomes possible.
Further, since the first optical coupling waveguide structure 1 and the second optical coupling waveguide structure 2 are individually mounted on the light emitting element 11 and the substrate 12 with an optical transmission path, respectively, Can be easily adjusted. Therefore, the lengths are adjusted so that the end portions of the first optical coupling waveguide structure 1 and the second optical coupling waveguide structure 2 are close to the light emitting element and the optical transmission path, respectively, at the time of optical coupling. Thus, it is easy to obtain high coupling efficiency.

  The first optical coupling waveguide structure 1 and the second optical coupling waveguide structure 2 are individually mounted on the light emitting element 11 and the substrate 12 with an optical transmission path, for example, in a wafer state. Or in a state before the substrate is cut out. Furthermore, after the waveguide structure is formed, an optical transmission system can be realized only by mounting the optical element and the substrate with the transmission path, so that the process may be the same as that for mounting an ordinary electronic component, which is excellent in mass productivity. There is.

Further, the material used for the optical coupler 10 composed of the first optical coupling waveguide structure 1 and the second optical coupling waveguide structure 2 is the same as that conventionally used for the waveguide structure. Can be used, and the material selectivity is excellent.
A second embodiment of the optical coupler of the present invention will be described below with reference to FIG. In this embodiment, an example in which the light emitting element 11 is mounted on the substrate 12 with the optical transmission path is shown, but the same applies to the case where other optical elements such as a light receiving element are mounted. The optical coupler 20 of the present embodiment includes a clad 1b of each of the first optical coupling waveguide structure 1 and the second optical coupling waveguide structure 2 on each of the light emitting element 11 and the optical transmission path-equipped substrate 12. Only 2b is attached in advance.

  2A, after filling the uncured clad material 22 in the optical axis direction of the light emitting element 11 and forming the shape of the clad 1b with the mold material 21 having the shape of the core 1a, the clad material 22 is formed. Is cured (FIG. 2 (a) bottom). In the present embodiment, the positioning of the light emitting element 11 and the first optical coupling waveguide structure 1 is performed by positioning the mold 21 and the light emitting element 11 when forming the shape of the core 1a in the clad 1b. it can.

  The clad 2 b is formed on the substrate 12 with an optical transmission path in the same manner as the clad 1 b is formed on the light emitting element 11. Also in this case, the positioning of the optical transmission path 13 provided on the optical transmission path-equipped substrate 12 and the second optical coupling waveguide structure 2 is performed when the core 2a is formed in the cladding 2b. The positioning can be performed by positioning another mold material having a shape and the optical transmission line 13.

  In this embodiment, the respective cores 1a and 2a of the first optical coupling waveguide structure 1 and the second optical coupling waveguide structure 2 are mounted or mounted when the light emitting element 11 is mounted on the optical transmission line 12. Later formed. As shown in FIG. 2B, the clad 1b formed on the light emitting element 11 and the clad 2b formed on the substrate 12 with an optical transmission path are positioned, and then a core material is applied to the portion formed in the core shape. Fill. Thereby, the respective cores 1a and 2a of the first optical coupling waveguide structure 1 and the second optical coupling waveguide structure 2 are integrally formed.

  As described above, since the cores 1a and 2a are integrally formed, no interface is formed between the cores 1a and 2a, and high coupling efficiency and high transmission quality can be realized. Moreover, the said core material can be used as sealing resin which seals the coupling | bond part of the light emitting element 11 and the optical transmission path 12, and forms the cores 1a and 2a and seals the said coupling | bond part integrally. Is possible. Thereby, the mounting process of the light emitting element 11 to the board | substrate 12 with an optical transmission path is simplified.

  A third embodiment of the optical coupler of the present invention will be described below with reference to FIG. Also in this embodiment, an example is shown in which the light emitting element 11 is mounted on the substrate 12 with an optical transmission path, but the same applies to the case where another optical element such as a light receiving element is mounted.

  The optical coupler 30 according to the present embodiment positions the mold 31 having the shape of the core 1a and the light emitting element 11 before filling the uncured clad material in the optical axis direction of the light emitting element 11 (FIG. 3 ( a)). Thereafter, the clad material is filled around the mold material 31 and cured to form the clad 1b.

  The clad 2 b is formed on the substrate 12 with an optical transmission path in the same manner as the clad 1 b is formed on the light emitting element 11. Also in this case, the positioning of the optical transmission path 13 provided on the substrate 12 with the optical transmission path and the second optical coupling waveguide structure 2 is performed between the optical transmission path 13 and another mold having the shape of the core 2a. Can be done by positioning.

After the clads 1b and 2b are formed on the light emitting element 11 and the optical transmission line 12, respectively, the cores 1a and 2a are formed by filling the core agent in the same manner as in the second embodiment. The optical transmission line 12 can be optically coupled (FIG. 3B).
A fourth embodiment of the optical coupler of the present invention will be described below with reference to FIG. In this embodiment, an example in which the light emitting element 11 is mounted on the substrate 12 with the optical transmission path is shown, but the same applies to the case where other optical elements such as a light receiving element are mounted. The optical coupler 40 of the present embodiment includes a first optical coupling waveguide structure 1 having a substantially convex core 1a, 2a on each of the light emitting element 11 and the substrate 12 with an optical transmission path, and a second optical coupling. The waveguide structure 2 for use is attached in advance.

As shown in FIG. 4 (a), an uncured clad material is filled in the optical axis direction of the light-emitting element 11, a hard core 1a having a substantially convex shape is inserted into the clad 1b, and then the clad material is cured. Let In the present embodiment, the positioning of the light emitting element 11 and the first optical coupling waveguide structure 1 can be performed when the core 1a is inserted into the clad 1b.
Similarly, by inserting a core 2a having a substantially convex shape into the clad 2b and curing, the second optical coupling waveguide structure 2 can be formed on the substrate 12 with an optical transmission path. Further, the positioning of the optical transmission path 13 provided on the optical transmission path-equipped substrate 12 and the second optical coupling waveguide structure 2 can be performed when the core 2a is inserted into the clad 2b.

  The optical coupling between the light emitting element 11 and the optical transmission path 13 can be performed by positioning the ends of the substantially convex core 1a and core 2a (FIG. 4B). The end portions of the core 1a and the core 2a are substantially convex bottom portions that are located outside the clads 1b and 2b, respectively. Therefore, the two end portions can be easily positioned.

  Since the end portions of the core 1a and the core 2a are not covered with the clads 1b and 2b, it is preferable to reduce the thickness of the end portions as much as possible. As a result, it is possible to avoid a decrease in coupling efficiency at the end portions of the core 1a and the core 2a. The coupling portion between the first optical coupling waveguide structure 1 and the second optical coupling waveguide structure 2 formed as described above is sealed and fixed with the sealing resin 15.

A fifth embodiment of the optical coupler of the present invention will be described below with reference to FIG. In this embodiment, an example in which the light emitting element 11 is mounted on the substrate 12 with the optical transmission path is shown, but the same applies to the case where other optical elements such as a light receiving element are mounted. The optical coupler 50 of this embodiment forms the clads 1b and 2b after forming the cores 1a and 2a on the light emitting element 11 and the substrate 12 with an optical transmission path, respectively, and at the interface between the clads 1b and 2b. It is designed to be optically coupled.
An uncured core material 51 is filled in the direction of the optical axis of the light emitting element 11, and the shape of the core 1 a is formed with the mold material 52 having the shape of the clad 1 b, and then the core material 51 is cured (the lower stage in FIG. 5A). . In the present embodiment, the light emitting element 11 and the first optical coupling waveguide structure 1 are positioned by positioning the mold material 52 and the light emitting element 11 when forming the shape of the cladding 1b on the core 1a. it can. Thereafter, the cladding 1b is formed.

The core 2a and the clad 2b are formed on the substrate 12 with an optical transmission line in the same manner as the core 1a and the clad 1b are formed on the light emitting element 11. Also in this case, the positioning of the optical transmission path 13 provided on the substrate with optical transmission path 12 and the second optical coupling waveguide structure 2 is performed between the optical transmission path 13 and another mold having the shape of the clad 2b. Can be done by positioning.
Optical coupling between the light emitting element 11 and the optical transmission line 13 can be performed by positioning the ends of the core 1a and the core 2a and joining the clad 1b and the clad 2b (FIG. 5B). Since the distance from the joint portion to the core 1a and the core 2a is not a waveguide structure, the thickness of this distance is preferably as small as possible. As a result, it is possible to avoid a decrease in coupling efficiency at the end portions of the core 1a and the core 2a. The coupling portion between the first optical coupling waveguide structure 1 and the second optical coupling waveguide structure 2 formed as described above is sealed and fixed with the sealing resin 15.

  A sixth embodiment of the optical coupler of the present invention will be described below with reference to FIG. Also in this embodiment, an example is shown in which the light emitting element 11 is mounted on the substrate 12 with an optical transmission path, but the same applies to the case where another optical element such as a light receiving element is mounted. The optical coupler 60 of the present embodiment is formed using a mixed material 61 of two kinds of resins having different refractive indices from the curing start point.

  A light-emitting element 11 is filled with a mixed material 61 of two types of resins having different refractive indices from the curing start point in the optical axis direction, cured with light 62 using the light path of the light-emitting element as a core 1a, and an uncured material The clad 1b is cured by light 63 having characteristics different from those of the light 62 (FIG. 6A). When the light 62 has the same characteristics as the light from the light emitting element, the core 1a can be formed by the light from the light emitting element. Since the core 1a and the clad 1b have different refractive indexes, a waveguide structure is formed.

  The core 2a and the clad 2b are formed on the substrate 12 with an optical transmission line in the same manner as the core 1a and the clad 1b are formed on the light emitting element 11. In this case, the light 62 forming the core 2a may be propagated through the optical transmission line 13 and irradiated.

The optical coupling between the light emitting element 11 and the optical transmission line 13 can be performed by positioning the ends of the core 1a and the core 2a (FIG. 6B). The coupling portion between the first optical coupling waveguide structure 1 and the second optical coupling waveguide structure 2 formed as described above is sealed and fixed with the sealing resin 15.
A seventh embodiment of the optical coupler of the present invention will be described below with reference to FIG. In the optical coupler 70 of the present embodiment, the diameter of the core 1a of the first optical coupling waveguide structure 1 mounted on the light emitting element 11 is the same as that of the second optical coupling mounted on the substrate 12 with optical transmission path. It is formed smaller than the diameter of the core 2 a of the waveguide structure 2.

  As described above, the core diameter of the first optical coupling waveguide structure 1 on the light emitting side (output side) is smaller than the core diameter of the second optical coupling waveguide structure 2 on the light receiving side (input side). By doing so, high coupling efficiency can be ensured without positioning the first optical coupling waveguide structure 1 and the second optical coupling waveguide structure 2 with high accuracy.

  The same can be done when the light receiving element 81 is mounted on the substrate 12 with the optical transmission path instead of the light emitting element 11. FIG. 8 is a schematic diagram showing an embodiment in which the light receiving element 81 is mounted on the substrate 12 with an optical transmission path. In the figure, the core diameter of the second optical coupling waveguide structure 2 on the output side is made smaller than the core diameter of the first optical coupling waveguide structure 1 on the input side. Accordingly, high coupling efficiency can be ensured without positioning the first optical coupling waveguide structure 1 and the second optical coupling waveguide structure 2 with high accuracy.

  The eighth embodiment of the optical coupler of the present invention will be described below with reference to FIG. In the present embodiment, an example in which the light receiving element 81 is mounted on the substrate 12 with an optical transmission path is shown, but the same applies to the case where another optical element such as a light emitting element is mounted. Contrary to the seventh embodiment, in the optical coupler 90 of the present embodiment, the diameter of the core 1a of the first optical coupling waveguide structure 1 mounted on the light receiving element 81 on the input side is the output side. The diameter of the core 2a of the second optical coupling waveguide structure 2 mounted on the optical transmission line 12 is smaller.

  When the core diameter on the output side (core 2a in FIG. 9) is relatively large, for example, 40 to 50 μm, it becomes multimode light during propagation of the core 2a. Therefore, as in the present embodiment, the core diameter on the input side is made smaller than the core diameter on the output side, so that high frequency components are removed and only the necessary mode light is focused on the input side (core 1a in FIG. 9). It is possible to achieve high quality light propagation.

  A ninth embodiment of the optical coupler of the present invention will be described below with reference to FIG. Also in this embodiment, an example is shown in which the light emitting element 11 is mounted on the substrate 12 with an optical transmission path, but the same applies to the case where another optical element such as a light receiving element is mounted.

  In the optical coupler 100 of the present embodiment, in the first optical coupling waveguide structure 1 attached to the light emitting element 11, an end portion 71 of the core 1a adjacent to the light emitting element 11 is formed in a lens shape. Similarly, in the second optical coupling waveguide structure 2 attached to the substrate 12 with an optical transmission path, an end portion 72 of the core 2a close to the optical transmission path 13 is formed in a lens shape.

  As described above, by forming the end 71 close to the light emitting element 11 of the core 1a and the end 72 close to the optical transmission path 12 of the core 2a into a lens shape, respectively, the lens effect is achieved at the end 71 and the end 72. Can be realized. As an example, as shown in FIG. 10 (b), the light output from the core 2a can be narrowed to reach the end face 14 at the end 72, and the coupling efficiency can be increased.

  A tenth embodiment of the optical coupler of the present invention will be described below with reference to FIG. In the optical coupler 110 of the present embodiment, the exit side of the core 2a of the second optical coupling waveguide structure 2 mounted on the substrate 12 with an optical transmission path is branched into two. That is, the second optical coupling waveguide structure 2 forms a demultiplexing waveguide circuit.

  As in the optical coupler 110 of the present embodiment, by forming a demultiplexing waveguide circuit with the first optical coupling waveguide structure 1 or the second optical coupling waveguide structure 2, the module has a high density. It is possible to manufacture a structure having the characteristics of a simple waveguide circuit. Although FIG. 11 shows an example of the second optical coupling waveguide structure 2 branched into two, it is possible to form a higher-density waveguide circuit by further increasing the number of branches. .

  Note that the description in the present embodiment shows an example of the optical coupler according to the present invention, and the present invention is not limited to this. The detailed configuration and detailed operation of the optical coupler in the present embodiment can be changed as appropriate without departing from the spirit of the present invention.

FIG. 1 is a schematic diagram showing a first embodiment of the present invention in which a light emitting element and an optical transmission line are optically coupled. (A) has shown the state before mounting a light emitting element on a board | substrate with an optical transmission path, (b) has each shown the state after mounting. FIG. 2 is a schematic view showing a second embodiment of the optical coupler of the present invention. (A) has shown the state of the light emitting element before mounting in a board | substrate with an optical transmission path, (b) has each shown the state after mounting. FIG. 3 is a schematic view showing a third embodiment of the optical coupler of the present invention. (A) has shown the state of the light emitting element before mounting in a board | substrate with an optical transmission path, (b) has each shown the state after mounting. FIG. 4 is a schematic view showing a fourth embodiment of the optical coupler of the present invention. (A) has shown the state of the light emitting element before mounting in a board | substrate with an optical transmission path, (b) has each shown the state after mounting. FIG. 5 is a schematic view showing a fifth embodiment of the optical coupler of the present invention. (A) has shown the state of the light emitting element before mounting in a board | substrate with an optical transmission path, (b) has each shown the state after mounting. FIG. 6 is a schematic view showing a sixth embodiment of the optical coupler of the present invention. (A) has shown the state of the light emitting element before mounting in a board | substrate with an optical transmission path, (b) has each shown the state after mounting. FIG. 7 is a schematic view showing a seventh embodiment of the optical coupler of the present invention. FIG. 8 is a schematic view showing a seventh embodiment of the optical coupler of the present invention. FIG. 9 is a schematic view showing an eighth embodiment of the optical coupler of the present invention. FIG. 10 is a schematic view showing a ninth embodiment of the optical coupler of the present invention. FIG. 11 is a schematic diagram showing a tenth embodiment of the optical coupler of the present invention. FIG. 12 is a schematic diagram showing a typical example of a conventional lens-type optical coupling means. FIG. 13 is a schematic diagram showing an example of a conventional transmission line type optical coupling means. FIG. 14 is a schematic diagram showing another example of a conventional transmission line type optical coupling means.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... 1st optical coupling waveguide structure 2 ... 2nd optical coupling waveguide structure 1a, 2a ... Core 1b, 2b ... Cladding 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110 ... optical coupler 11 ... light emitting element 12 ... substrate with optical transmission path 13 ... optical transmission path 14 ... end face 15 ... sealing Resin 21 ... Mold material 22 ... Cladding material 31 ... Mold material 51 ... Core material 52 ... Mold material 61 ... Resin mixture 62 ... Light 63 ... Light 71, 72 ... End 81: light receiving element 101 ... light emitting element 102 ... optical transmission path 103, 104 ... micro lens 105 ... end face 121 ... optical pin 131 ... waveguide sheet 132 ... Waveguide structure

Claims (6)

An optical coupler for optically coupling an optical element to a substrate with an optical transmission path comprising a substrate and an optical transmission path having an end face that changes the optical axis in a direction orthogonal to the optical axis ,
A first optical coupling waveguide structure and a second optical coupling waveguide structure having an optical axis orthogonal to the optical axis of the optical transmission line; a part of the first optical coupling waveguide structure; All attached to the optical element ,
An optical coupler, wherein a part or all of the second optical coupling waveguide structure is mounted at a position on the substrate with an optical transmission path facing the end face by a predetermined distance . In the first optical coupling waveguide structure and the second optical coupling waveguide structure, only the cladding is mounted on the optical element and the substrate with the optical transmission path, respectively.
The optical coupler of claim 1 wherein the first core of the optical coupling waveguide structure and said second optical coupling waveguide structure is characterized by being formed integrally. The core diameter of the first optical coupling waveguide structure on the optical output side or the second optical coupling waveguide structure on the optical output side is equal to the second optical coupling waveguide structure on the optical input side or the first light. The optical coupler according to claim 1 , wherein the optical coupler is smaller than a core diameter of the coupling waveguide structure. The core diameter of the first optical coupling waveguide structure on the optical output side or the second optical coupling waveguide structure on the optical output side is equal to the second optical coupling waveguide structure on the optical input side or the first light. The optical coupler according to claim 1 , wherein the optical coupler is larger than a core diameter of the coupling waveguide structure. 5. The input end of the first optical coupling waveguide structure or the second optical coupling waveguide structure on the light output side has a lens shape. 5 . The optical coupler according to claim 1. 5. The output end of the first optical coupling waveguide structure or the second optical coupling waveguide structure on the optical input side has a lens shape. 5 . The optical coupler according to claim 1.

Images