JP6364884B2 - Optical waveguide, opto-electric hybrid board, optical module, and electronic device - Google Patents

Description

  The present invention relates to an optical waveguide, an opto-electric hybrid board, an optical module, and an electronic device.

  In the optical waveguide, light introduced from one end of the core portion is transmitted (conveyed) to the other end while being reflected at the boundary with the cladding portion. A light emitting element such as a semiconductor laser is disposed on the incident side of the optical waveguide, and a light receiving element such as a photodiode is disposed on the emission side. Light incident from the light emitting element propagates through the optical waveguide, is received by the light receiving element, and performs communication based on the flickering pattern of the received light or its intensity pattern.

  When optically coupling such an optical waveguide to a light emitting element or a light receiving element, the optical path of the core part is converted via a mirror formed in the core part of the optical waveguide, and the optical path is set in a direction perpendicular to the main surface of the optical waveguide. A structure that optically couples by guiding is studied. For example, Patent Document 1 discloses an optical module having a build-up substrate, an optical waveguide provided on the build-up substrate, and a light emitting element disposed on the optical waveguide. And a core in the optical waveguide are optically connected via a mirror formed in the optical waveguide.

  Since there is a demand for downsizing of the optical module having such a structure, attempts have been made to increase the density of the cores by narrowing the interval between a plurality of cores arranged in parallel in the optical waveguide. As a result, the transmission capacity per unit area of the optical module is increased, and downsizing is possible. However, when the interval between the cores is narrowed, there is a problem that it becomes difficult to secure a space for forming the mirror when the mirror is formed in accordance with the core. Since the size of the mirror affects the optical coupling efficiency between the core and the optical element via the mirror, it is necessary to ensure a certain size.

JP 2006-145789 A

  An object of the present invention is to provide an optical waveguide that can achieve both high density of the core portion and high optical coupling efficiency with an optical component provided outside, and includes such an optical waveguide, enabling high-quality optical communication. To provide an opto-electric hybrid board, an optical module, and an electronic device.

Such an object is achieved by the present inventions (1) to (8) below.
(1) A first core portion and a second core portion that extend in the X-axis direction and are aligned in the Y-axis direction intersecting the X-axis direction;
A first mirror having a width wider than that of the first core portion provided in the middle of the longitudinal direction of the first core portion or on an extension line, and converts a first optical path extending from the first mirror to the −X side. A first mirror that
A second mirror having a width wider than that of the second core portion provided on the middle of the longitudinal direction of the second core portion or on an extension line so as to be shifted to the −X side with respect to the first mirror, A second mirror for converting a second optical path extending from the mirror to the -X side;
Have
The first core part includes a wide part, a first variable width part gradually changing in width so as to be narrower than the wide part, a narrow part having a narrower width than the wide part, and the narrow part A second variable width portion whose width gradually changes so as to be wider than the first portion, in this order, and the second mirror and the narrow width portion correspond to each other at the position in the X-axis direction. An optical waveguide characterized by

  (2) The optical waveguide according to (1), wherein when the virtual line that virtually extends the outer edge of the wide portion is drawn, the virtual line and the second mirror overlap each other.

(3) The shape of the first core portion in plan view is a shape having a line-symmetric relationship with respect to an axis that passes through the center of the width and is parallel to the X axis. Optical waveguide.

  (4) The width of the first mirror and the width of the second mirror are each larger than the distance between the center of the width of the first core part and the center of the width of the second core part, and twice the distance. The optical waveguide according to any one of (1) to (3), which is narrower.

  (5) Said (1) said 1st core part and said 2nd core part are formed by irradiating an energy ray with respect to the member which can change a refractive index by irradiation of an energy ray, respectively. Thru | or the optical waveguide in any one of (4).

  (6) An opto-electric hybrid board comprising the optical waveguide according to any one of (1) to (5) above.

  (7) An optical module comprising the opto-electric hybrid board according to (6) and an optical element.

  (8) An electronic apparatus comprising the optical waveguide according to any one of (1) to (5).

  According to the present invention, it is possible to obtain an optical waveguide that can achieve both high density of the core portion and high optical coupling efficiency with an optical component provided outside.

  Further, according to the present invention, an opto-electric hybrid board, an optical module, and an electronic device that are provided with such an optical waveguide and are capable of high-quality optical communication can be obtained.

It is a top view which shows 1st Embodiment of the optical waveguide of this invention. FIG. 2 is a partially enlarged plan view of the optical waveguide shown in FIG. 1. FIG. 2 is a cross-sectional view of the optical waveguide shown in FIG. 1 taken along line AA. FIG. 2 is a partially enlarged perspective view of the optical waveguide shown in FIG. 1. It is a top view which shows 2nd Embodiment of the optical waveguide of this invention. It is AA sectional view taken on the line of the optical waveguide shown in FIG. FIG. 6 is a partially enlarged perspective view of the optical waveguide shown in FIG. 5. It is sectional drawing which shows 3rd Embodiment of the optical waveguide of this invention. It is sectional drawing which shows 3rd Embodiment of the optical waveguide of this invention. It is a top view which shows 4th Embodiment of the optical waveguide of this invention. It is a top view which shows 5th Embodiment of the optical waveguide of this invention. It is a top view which shows 5th Embodiment of the optical waveguide of this invention. It is a top view which shows 5th Embodiment of the optical waveguide of this invention. It is a top view which shows 6th Embodiment of the optical waveguide of this invention. It is a longitudinal cross-sectional view which shows embodiment of the opto-electric hybrid board | substrate of this invention, and embodiment of the optical module of this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an optical waveguide, an opto-electric hybrid board, an optical module, and an electronic device according to the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

<Optical waveguide>
<< First Embodiment >>
First, a first embodiment of the optical waveguide of the present invention will be described.

  FIG. 1 is a plan view showing a first embodiment of the optical waveguide of the present invention. FIG. 2 is a partially enlarged plan view of the optical waveguide shown in FIG. FIG. 3 is a cross-sectional view of the optical waveguide shown in FIG. 4 is a partially enlarged perspective view of the optical waveguide shown in FIG. 1, 2, and 4, for convenience of explanation, the portions hidden behind the clad layer and the like are shown through. Moreover, in each figure, the dot is attached | subjected with respect to the core part. In the following description, for the sake of convenience of explanation, the upper part of FIG. 3 will be described as “upper” and the lower part thereof will be described as “lower”.

  An optical waveguide 1 shown in FIG. 1 has a sheet shape, and transmits an optical signal between a light incident part and a light emission part to perform optical communication.

  As shown in FIG. 3, the optical waveguide 1 includes a laminate 10 in which a clad layer 11, a core layer 13, and a clad layer 12 are laminated from below. In the core layer 13, a plurality of long core portions 14 (eight core portions 14 in FIG. 1) and side clad portions 15 provided adjacent to the side surfaces thereof are formed. In the optical waveguide 1 shown in FIGS. 1 to 3, the core portion 14 extends in the left-right direction of each drawing, and only the vicinity of the end portion in the longitudinal direction is shown in FIGS. The configuration of the end not shown is not particularly limited, but is preferably the same as the configuration shown in each drawing. 1-3 is the X-axis direction, the vertical direction in FIGS. 1 and 2 is the Y-axis direction, and the direction perpendicular to the X-axis direction and the Y-axis direction is the Z-axis direction (the vertical direction in FIG. 3). ). In the following description, the rightward direction in FIG. 1 is the + X side, and the leftward direction is the −X side. Further, the upward direction in FIG. 1 is the + Y side, and the downward direction is the −Y side.

  Moreover, in the core layer 13 shown to FIG. 1, 2, each core part 14 is formed so that the edge part of the right side of each core part 14 may be located inside the outer edge of the longitudinal direction. The side clad portion 15 occupies a space between the end portion of each core portion 14 and the outer edge of the core layer 13.

  The width (the length in the Y-axis direction) and the height (the thickness of the core layer 13) of the core portion 14 are not particularly limited, but are preferably about 1 to 200 μm, more preferably about 5 to 100 μm. preferable. Thereby, it is possible to increase the density of the core part 14 while increasing the transmission efficiency of the core part 14. That is, since the number of core portions 14 that can be laid per unit area can be increased, large-capacity optical communication can be performed even in a small area.

  Further, the refractive index distribution in the width direction and the refractive index distribution in the thickness direction of the optical waveguide 1 may be so-called step index (SI) type distributions in which the refractive index changes discontinuously, respectively. May be a so-called graded index (GI) type distribution in which the values continuously change.

  Further, the core portion 14 may be linear or curved in plan view. Furthermore, the core part 14 may branch on the way or may mutually cross | intersect.

  Furthermore, the cross-sectional shape of the core portion 14 is not particularly limited, and may be a circle such as a perfect circle, an ellipse, or an oval, or a polygon such as a triangle, a rectangle, a pentagon, or a hexagon. By being (rectangular shape), the core part 14 of the stable quality can be manufactured efficiently.

  On the other hand, the cladding layer 11 is provided below the core layer 13, and the cladding layer 12 is provided above the core layer 13.

  The average thickness of the cladding layers 11 and 12 is preferably about 0.05 to 1.5 times the average thickness of the core layer 13, and more preferably about 0.1 to 1.25 times. Specifically, the average thickness of the cladding layers 11 and 12 is preferably about 1 to 200 μm, more preferably about 3 to 100 μm, and further preferably about 5 to 60 μm. Thereby, the function as a clad part is ensured while preventing the optical waveguide 1 from becoming thicker than necessary.

  The clad layers 11 and 12 may be provided as necessary and may be omitted. Even in this case, for example, outside air functions as a cladding layer.

  The optical waveguide 1 is provided with a recess 170 formed by removing a part of the laminated body 10. That is, the optical waveguide 1 is provided with the laminated body 10 and the recessed part 170 formed in it. The concave portion 170 shown in FIG. 1 is located on the end of the core portion 14 in the longitudinal direction, that is, on the extension line of the core portion 14. A part of the inner surface of the recess 170 is an inclined surface 171 that is inclined with respect to the axis of the core portion 14.

  Further, the inside of the recess 170 is hollow. In other words, it can be said that the concave portion 170 is filled with air having a refractive index lower than that of the core portion 14. Therefore, the inclined surface 171 corresponds to an interface between air and the constituent material of the laminated body 10, and light propagating on the laminated body 10 side that is the high refractive index side is reflected by the inclined surface 171. Therefore, the inclined surface 171 functions as a mirror that converts the optical path of the core portion 14. That is, the inclined surface 171 can change its optical path by reflecting light that enters the core portion 14 from the left end of FIG.

  The vertical cross-sectional shape of the recess 170 shown in FIG. 3 is a trapezoid whose upper base is longer than the lower base. In addition, this longitudinal cross-sectional shape is not specifically limited, For example, a triangle, a parallelogram, etc. may be sufficient.

  3 and 4, the inclined surface 171 is a flat surface formed continuously from the cladding layer 12 through the core layer 13 to the middle of the cladding layer 11. Further, an upright surface 172 is provided at a position facing the inclined surface 171 on the inner surface of the recess 170. The upright surface 172 is a surface orthogonal to the axis of the core portion 14. The upright surface 172 is also a flat surface continuously formed from the clad layer 12 to the middle of the clad layer 11 through the core layer 13, similarly to the inclined surface 171.

  On the other hand, two surfaces of the inner surface of the concave portion 170 that are substantially parallel to the axis of the core portion 14 are also upright surfaces 173 and 174 that are substantially perpendicular to the upper surface of the cladding layer 12, respectively.

  The inclined surface 171 as described above and the three upright surfaces 172, 173 and 174 constitute the inner surface of the recess 170.

  Further, the shape of the opening of the recess 170 is rectangular as shown in FIG. In addition, the shape of this opening is not specifically limited, For example, other polygons, such as a quadrangle, a pentagon, and a hexagon, may be sufficient as a circle like an ellipse.

  A line segment (ridge line) formed by contact between the inclined surface 171 and the upper surface of the cladding layer 12 corresponds to the short side of the opening forming the rectangle of the recess 170. On the other hand, each of the line segments (ridge lines) in which the upright surfaces 172, 173, and 174 are in contact with the upper surface of the cladding layer 12 corresponds to the long side of the opening that forms the rectangle of the recess 170.

  As described above, the inclined surface 171 is inclined with respect to the axis of the core portion 14, but the optical axis conversion direction changes according to the inclination angle of the inclined surface 171. For this reason, the inclination angle of the inclined surface 171 is appropriately set according to the position of the optical component provided outside the optical waveguide 1.

  Here, among the plurality of core portions 14, the core portion 14 shown in FIG. 2 is particularly referred to as “core portion 14a”, and the core portion 14 adjacent to the core portion 14a is particularly referred to as “core portion 14b”. When the core portion 14a corresponds to the “first core portion”, the core portion 14b corresponds to the “second core portion”.

  Further, the inclined surface 171 provided at the right end of the core portion 14a is particularly referred to as an “inclined surface 171a”, and the inclined surface 171 provided at the right end of the core portion 14b is particularly referred to as an “inclined surface 171b”. When the inclined surface 171a corresponds to the “first mirror”, the inclined surface 171b corresponds to the “second mirror”.

  Further, the optical path of each core portion 14 and converted by the inclined surface 171a is particularly referred to as “optical path 140a”, and the optical path converted by the inclined surface 171b is particularly referred to as “optical path 140b”. The optical path 140a extends to the −X side from the inclined surface 171a, and similarly, the optical path 140b extends to the −X side from the inclined surface 171b. In FIG. 2, for convenience of illustration, a line passing through the center of the width of the core part 14 a is illustrated as “optical path 140 a”, and a line passing through the center of the width of the core part 14 b is illustrated as “optical path 140 b”.

  In FIG. 2, the inclined surface 171b is provided so as to be shifted to the −X side from the inclined surface 171a. Therefore, the inclined surface 171a and the inclined surface 171b are prevented from interfering with each other, and each of the inclined surface 171a and the inclined surface 171b can secure a sufficient area. Thereby, the reflection loss in the inclined surface 171a and the inclined surface 171b can be suppressed sufficiently. As a result, an optical waveguide with high optical coupling efficiency can be obtained when optically connected to an external optical component.

  The core portion 14a includes a wide portion 141a having a relatively wide width and a narrow portion 142a having a width smaller than that of the wide portion 141a in a plan view when viewed from the Z-axis direction. The narrow part 142a is located on the right side of the wide part 141a. That is, it can be said that the narrow portion 142a is located between the wide portion 141a and the inclined surface 171a.

  In the core portion 14b adjacent to the core portion 14a, the inclined surface 171b provided at the right end is provided at a position corresponding to the narrow width portion 142a of the core portion 14a in the position in the X-axis direction. In other words, the range occupied by the inclined surface 171b in the X-axis direction and the range occupied by the narrow-width portion 142a of the core portion 14a in the X-axis direction overlap at least partially. Even when the pitch P (see FIG. 2) between the core portion 14a and the core portion 14b is narrowed by overlapping the range occupied in the X-axis direction between the inclined surface 171b and the narrow width portion 142a, the inclined surface 171b. And interference with the core part 14a can be prevented. That is, even when the formation density of the core portions 14 formed in the core layer 13 is increased, it is possible to ensure a sufficient area of the inclined surface 171b while avoiding interference between the inclined surface 171b and the core portion 14a. . Therefore, it is possible to achieve both high density of the core portion 14 and high optical coupling efficiency with an external optical component.

  On the other hand, by increasing the width as much as possible except for the position corresponding to the inclined surface 171b, that is, by disposing the wide portion 141a, the transmission efficiency at that portion can be increased. Further, by applying the wide portion 141a to the portion of the core portion 14b exposed to the inclined surface 171, the area of the core portion 14b exposed to the inclined surface 171 can be secured widely. As a result, the optical coupling efficiency on the inclined surface 171 can be further increased.

The core portion 14a is positioned between the wide portion 141a and the narrow portion 142a, and a variable width portion 143a (first variable width portion) configured to gradually narrow toward the + X side. , And a variable width portion 144a (second variable width portion) that is positioned between the narrow width portion 142a and the inclined surface 171a and is configured to gradually increase in width toward the + X side. By providing the variable width portion 143a, the change in width between the wide width portion 141a and the narrow width portion 142a becomes moderate. For this reason, it is possible to reduce the probability of light leaking from the core portion 14a to the side cladding portion 15 with the change in width, and it is possible to suppress a decrease in transmission efficiency. Further, by providing the variable width portion 144a, the area of the core portion 14a exposed to the inclined surface 171a can be made wider than when the variable width portion 144a is not provided. Thereby, compared with the case where the variable width portion 144a is not provided, the probability that the light reflected on the inclined surface 171a is incident on the core portion 14a can be increased, and the optical coupling efficiency with an external optical component can be further increased. it can.

  On the other hand, in the present embodiment, the core part 14b also includes a wide part 141b having a relatively wide width and a narrow part 142b having a narrower width than the wide part 141b in plan view. The narrow part 142b is located on the right side of the wide part 141b.

  And the core part 14b is also located between the wide part 141b and the narrow part 142b, and between the narrow part 142b and the inclined surface 171b, the width part 143b which becomes narrow gradually as it goes to + X side. And a variable width portion 144b configured to gradually widen toward the + X side.

  With respect to such a core part 14b, in the core part 14 adjacent to the opposite side to the core part 14a, the inclined surface 171 provided at the right end of the core part 14b is also the narrow part 142b of the core part 14b at the position in the X side direction. Is provided at a position corresponding to. Thereby, even when the pitch is narrowed by the core part 14b and the core part 14 adjacent to it, interference with the inclined surface 171 and the core part 14b can be prevented.

  From the above, the relationship as described above that is satisfied between the core portion 14a and the inclined surface 171b provided at the right end of the core portion 14b adjacent thereto is similarly applied to the other core portions 14 and the inclined surface 171. As a result, even in the optical waveguide 1 having three or more core portions 14, the interference between the inclined surface 171 and the core portion 14 can be prevented while the pitch between the adjacent core portions 14 is narrowed. As a result, even when three or more core portions 14 are formed with high density, a sufficient area of the inclined surface 171 can be secured while avoiding interference between the inclined surface 171 and the core portion 14. It is possible to achieve both high density of the portion 14 and high optical coupling efficiency with an external optical component.

  Further, the width of the inclined surface 171a (the length in the Y-axis direction) is wider than the width of the core portion 14a. For this reason, the inclined surface 171a can reflect the light propagating through the core portion 14a in a sufficiently wide area, so that the reflection loss can be sufficiently suppressed. Note that the width of the inclined surface 171a being wider than the width of the core portion 14a means wider than the maximum width (maximum length in the Y-axis direction) of the core portion 14a.

  Similarly, the width of the inclined surface 171b (the length in the Y-axis direction) is wider than the width of the core portion 14b. For this reason, the inclined surface 171b can reflect the light propagating through the core portion 14b with a sufficiently large area, so that the reflection loss can be sufficiently suppressed. In addition, that the width of the inclined surface 171b is wider than the width of the core portion 14b means that it is wider than the maximum width (maximum length in the Y-axis direction) of the core portion 14b.

  In addition, in the wide part 141a of the core part 14a, since the width | variety is substantially constant, it can be paraphrased that the width | variety of the inclined surface 171a which concerns on this embodiment is wider than the width | variety of the wide part 141a.

  The width W2 is preferably about 20 to 95% of the width W1, and more preferably about 30 to 80%. If the width W2 is less than the lower limit value, the width W2 becomes too narrow, so that the transmission efficiency of light propagating through the narrow portion 142a is lowered, and the transmission efficiency of the entire core portion 14a may be lowered. On the other hand, if the width W2 exceeds the upper limit, the difference between the width W2 of the narrow portion 142a and the width W1 of the wide portion 141a becomes small, and accordingly, the separation distance between the inclined surface 171b and the narrow portion 142a. Therefore, it is difficult to sufficiently narrow the pitch P between the core portion 14a and the core portion 14b, and it is difficult to increase the density of the core portion 14.

  The pitch P between the core portion 14a and the core portion 14b is a distance between the center of the width W1 of the core portion 14a and the center of the width W2 of the core portion 14b.

  Here, a case is considered where an imaginary line in which the outer edge of the wide portion 141a is virtually extended along the X-axis direction in FIG. 2 is drawn. Among these, it is preferable that the imaginary line L drawn at a position corresponding to the narrow width portion 142a overlaps the inclined surface 171b in plan view as shown in FIG. Thus, the imaginary line L and the inclined surface 171b overlap each other, so that the pitch P between the core portion 14a and the core portion 14b can be sufficiently shortened, and at the same time, the width of the inclined surface 171b can be sufficiently widened. That is, since the inclined surface 171b having a width that cannot exist when the narrow width portion 142a is not provided can be realized without changing the pitch P, the viewpoint of particularly improving the optical coupling efficiency with an external optical component. It is useful from.

  At this time, the shortest distance S (see FIG. 2) between the inclined surface 171b and the core portion 14a in the Y-axis direction varies depending on the refractive index difference between the core portion 14 and the side cladding portion 15, but is 0.1 × {( W1−W2) / 2} or more and 0.9 × {(W1−W2) / 2} or less is preferable, and 0.2 × {(W1−W2) / 2} or more and 0.8 × {(W1− W2) / 2} or less is more preferable. Thereby, the pitch P is narrowed to the maximum and the width of the inclined surface 171b is maximized while suppressing an increase in defects (for example, crosstalk) due to the inclined surface 171b and the narrow portion 142a being too close to each other. Can do.

  Further, the width of the inclined surface 171a and the width of the inclined surface 171b are preferably set to be wider than the pitch P and smaller than twice the pitch P, respectively. By setting in this way, the inclined surface 171a and the inclined surface 171b having a sufficient area with respect to the core portion 14 are obtained. The inclined surface 171a and the inclined surface 171b having such an area are unlikely to cause an increase in reflection loss even in a harsh environment. That is, for example, when the optical waveguide 1 is used at a high temperature, the inclined surface 171a and the inclined surface 171b tend to be distorted and the reflection loss tends to increase with the thermal expansion of the optical waveguide 1, but the width of the inclined surface 171a is increased. Further, when the width of the inclined surface 171b is within the above range, such distortion can be suppressed. As a result, the optical waveguide 1 can be obtained in which an increase in reflection loss is minimized and a decrease in optical coupling efficiency with an external optical component is suppressed even in a harsh environment.

  The width of the inclined surface 171a and the width of the inclined surface 171b are more preferably 1.1 to 1.9 times the pitch P, and more preferably 1.2 to 1.8 times the pitch P. Is done.

  Moreover, although the pitch P is suitably set according to the width of the core part 14, it is preferable that it is about 10-1000 micrometers, and it is more preferable that it is about 20-500 micrometers. Thereby, the optical waveguide 1 in which the core part 14 is formed with a sufficiently high density is obtained. Such an optical waveguide 1 has a sufficient transmission capacity even if it is narrow.

  The shape of the core portion 14 in plan view is not particularly limited, but is preferably a shape having a line-symmetric relationship with respect to an axis that passes through the center of the width and is parallel to the X axis. The core portion 14 having such a shape can suppress a decrease in transmission efficiency.

  The concave portion 170 may be filled with a material having a lower refractive index than the core portion 14 (low refractive index material) as necessary. Even in this case, the inclined surface 171 reflects light based on the refractive index difference between the constituent material of the recess 170 and the constituent material of the core portion 14. Further, when the low refractive index material is solid, it is difficult to prevent foreign matter from entering the recess 170, and the influence of the external environment of the optical waveguide 1 is difficult to directly reach the vicinity of the recess 170. Therefore, the weather resistance of the optical waveguide 1 is reduced. Can increase the sex.

  The low refractive index material is appropriately selected according to the refractive index of the core portion 14 and is not limited at all. Examples thereof include various resin materials such as silicone resins, polyolefin resins, and polyester resins. The lower the refractive index of the low refractive index material, the better as it is lower than the refractive index of the core portion 14, and it is preferable to be lower than 0.01.

  In addition, a material having light reflectivity, for example, a metallic material having a metallic luster, or the like may be formed on the inclined surface 171 as necessary. In this case, the recess 170 may be filled with various materials, and the refractive index of the material is not particularly limited.

  Examples of the metal material include simple substances or compounds of metals such as aluminum, silver, and nickel.

  The inclined surface 171 is appropriately set according to the position of the optical component optically connected to the core portion 14 as described above. When the lower surface of the core layer 13 is used as the reference surface, the inclined surface 171 and the inclined surface are inclined. The angle formed by the surface 171 is preferably about 30 to 60 °, and more preferably about 40 to 50 °. By setting the tilt angle within the above range, it is possible to efficiently convert the optical path of the core portion 14 on the tilted surface 171 and to suppress the loss accompanying the optical path conversion. The angle formed between the reference surface and the inclined surface 171 refers to an inner angle formed on the side opposite to the concave portion 170 among the inner angles formed by the reference surface and the inclined surface 171.

  On the other hand, the angle formed between the reference surface and the upright surfaces 172, 173, 174 is preferably about 60 to 90 °, more preferably about 70 to 90 °, and still more preferably about 80 to 90 °. The By setting the angle formed by the reference surface and the upright surfaces 172, 173, and 174 within the above range, particularly the stress applied to the interface between the cladding layer 11 and the core layer 13 can be further reduced, and the inclination is caused by this stress. An increase in reflection loss of the surface 171 can be suppressed. In each figure, the angle formed by the reference surface and the upright surfaces 172, 173, 174 is shown as approximately 90 °. Further, the angle formed by the reference surface and the upright surfaces 172, 173, 174 is an inner angle formed on the opposite side to the concave portion 170 side among the angles of the inner angles formed by the reference surface and the upright surfaces 172, 173, 174. This means the angle.

  The maximum depth of the recess 170 is appropriately set from the thickness of the laminated body 10 and is not particularly limited, but is preferably 1 to 500 μm from the viewpoint of mechanical strength and flexibility of the optical waveguide 1. And more preferably about 5 to 400 μm. The concave portion 170 only needs to reach at least the core layer 13 and does not have to reach the cladding layer 11.

  The constituent materials (main materials) of the core layer 13 and the cladding layers 11 and 12 as described above are, for example, acrylic ether, methacrylic resin, polycarbonate, polystyrene, cyclic ether resin such as epoxy resin and oxetane resin. , Polyamide, polyimide, polybenzoxazole, polysilane, polysilazane, silicone resin, fluorine resin, polyurethane, polyolefin resin, polybutadiene, polyisoprene, polychloroprene, polyester such as PET and PBT, polyethylene succinate, polysulfone, poly Various resin materials such as ethers and cyclic olefin resins such as benzocyclobutene resins and norbornene resins can be used. In addition, as cyclic olefin resin, what was described in Unexamined-Japanese-Patent No. 2010-090328 is used, for example.

  Further, the resin material may be a composite material in which materials having different compositions are combined. Since these are relatively easy to process, they are suitable as constituent materials for the core layer 13 and the clad layers 11 and 12 in which the concave portions 170 are formed.

  In addition, the configuration of the left end (not shown) of the optical waveguide 1 is not particularly limited, and as described above, it may be the same as the configuration of the right end, or an optical connector or the like may be attached. Further, even when the optical waveguide 1 is branched in the middle, it is sufficient that the configuration shown in each drawing is applied to at least one end portion, and the configuration of the other end portions is not particularly limited.

  Moreover, the number of the core parts 14 formed in the optical waveguide 1 is not particularly limited, but is about 1 to 100, for example.

  Further, as a method of forming the core portion 14 and the side cladding portion 15 in the core layer 13, for example, a method of repeatedly performing a film forming step, a patterning step combining a photolithography technique and an etching technique, or a film forming process. This method uses a composition having a refractive index modulation ability (for example, refractive index modulation by photobleaching or monomer diffusion) in which a refractive index is changed by irradiation of energy rays, a method of repeatedly performing a process and a patterning process by imprint technology. The method etc. which irradiate an energy beam with the desired pattern to the member which consists of things are mentioned. Photobleaching is a phenomenon in which the refractive index changes by breaking bonds in the molecule as energy is applied, and monomer diffusion uses a polymer and a monomer having different refractive indexes to give energy. Along with this, it is a phenomenon in which a monomer dispersed in a polymer is unevenly distributed to form a refractive index distribution. In addition, the principle of refractive index modulation includes photoisomerization and photodimerization.

Among these, it is preferable to form the core part 14 and the side clad part 15 using the method of irradiating an energy ray to the member which consists of a composition which has refractive index modulation ability. According to this method, even when the pitch P is narrow, the core portion 14 can be formed with high dimensional accuracy. In particular, when the core portion 14a includes the variable width portion 143a and the variable width portion 144a, a smooth shape can be formed, so that light leakage in the variable width portion 143a and the variable width portion 144a can be suppressed. . As a result, the core part 14 with higher transmission efficiency can be formed.
Examples of energy rays include visible light, ultraviolet rays, lasers, and electron beams.

  Here, as a material which produces monomer diffusion, the photosensitive resin composition etc. which were described in Unexamined-Japanese-Patent No. 2010-090328 are mentioned, for example.

  On the other hand, in the case of refractive index modulation based on the principles of photobleaching, photoisomerization, and photodimerization, the amount of change in refractive index can be adjusted according to the irradiation amount of the energy beam to be irradiated. In photobleaching, the molecular structure in the material is cut by irradiation with energy rays, and the leaving group is released from the main chain. This changes the refractive index of the material. In photoisomerization and photodimerization, the material is photoisomerized or photodimerized by irradiation with energy rays, and the refractive index of the material changes.

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

  Examples of materials that cause photoisomerization include norbornene resins described in JP-A-2005-164650.

  Moreover, as a material which produces photodimerization, the photosensitive resin composition etc. which were described in Unexamined-Japanese-Patent No. 2011-105791 are mentioned, for example.

  In addition, by gradually changing the irradiation amount of the energy beam to be irradiated, the formed refractive index distribution also has a smooth refractive index change. As a method of gradually changing the irradiation amount of the energy beam to be irradiated, for example, a method using a multi-tone mask such as a gray tone mask or a half tone mask, a method of scanning an energy beam having a distribution of light intensity, Examples include a method of irradiating while changing the irradiation time.

  In addition, as an apparatus used for energy beam irradiation, an apparatus for irradiating energy beam through a photomask corresponding to a waveguide pattern to be formed may be used, but the region irradiated with energy beam is finely controlled. It is preferable to use an apparatus (maskless irradiation apparatus) that selectively irradiates only an area to be irradiated without using a photomask. Thereby, an energy beam irradiation process can be efficiently performed with high spatial resolution. In addition, since a photomask is not required, the cost of energy beam irradiation processing can be reduced, and different waveguide patterns can be quickly switched, so that a variety of products can be produced in small quantities.

Examples of the maskless irradiation apparatus include various spatial light modulation elements such as a reflective spatial light modulation element such as a digital micromirror device (DMD) and a transmission spatial light modulation element such as a liquid crystal display element (LCD). Is used to emit energy rays from a generation source as a spatially modulated beam.
Among these, as a generation source, a lamp, a laser light source, LED, etc. are used, for example.

  Other spatial light modulators than the above are MEMS (Micro Electro Mechanical System) -type spatial light modulators such as spatial light modulators (SLMs) and electro-optic effects such as PLZT elements. Examples thereof include a spatial light modulation element that modulates light and a liquid crystal light shutter.

  Further, a source in which a plurality of light emitting points are arranged in a grid shape, for example, a laser diode (LD) array, a light emitting diode (LED) array, an organic EL array, or the like can be used for this exposure process. When such a generation source is used, the spatial light modulation element can be omitted.

  In addition to the generation source and the spatial light modulation element, the maskless irradiation apparatus has an XYZ stage that drives the object to be processed, various optical systems, a control unit that controls the operation of the generation source and the spatial light modulation element, and the like. May be.

  Moreover, the recessed part 170 can be formed with the various processing method which can remove a part of laminated body 10. FIG. Examples of such processing methods include mechanical processing such as cutting, laser processing, electron beam processing, imprint processing, and the like.

<< Second Embodiment >>
Next, a second embodiment of the optical waveguide of the present invention will be described.

  FIG. 5 is a plan view showing a second embodiment of the optical waveguide of the present invention. FIG. 6 is a cross-sectional view of the optical waveguide shown in FIG. FIG. 7 is a partially enlarged perspective view of the optical waveguide shown in FIG. In FIGS. 5 and 7, for the convenience of explanation, portions hidden behind the cladding layer and the like are shown in perspective. Moreover, in each figure, the dot is attached | subjected with respect to the core part.

  Hereinafter, although 2nd Embodiment is described, in the following description, it demonstrates centering around difference with 1st Embodiment, The description is abbreviate | omitted about the same matter.

  The optical waveguide 1 according to the second embodiment is the same as the optical waveguide 1 according to the first embodiment, except that the longitudinal cross-sectional shape of the recess is different.

  That is, the vertical cross-sectional shape of the recess 170 shown in FIG. 5 is a trapezoid whose upper base is longer than the lower base, as shown in FIG. In the first embodiment, the surface facing the inclined surface 171 is the “upright surface 172”, whereas in the present embodiment, the surface is an “inclined surface 172 '”. However, the inclined surface 171 is not different from the first embodiment.

  The recess 170 having such an inclined surface 172 ′ has a length in the X-axis direction of the opening that is longer than that in the first embodiment. That is, although the length of the inclined surface 171 in the X-axis direction does not change, the range occupied by the concave portion 170 in the X-axis direction is increased by the amount of the inclined surface 172 '. For this reason, for example, the range that the narrow portion 142a of the core portion 14a provided corresponding to the inclined surface 171b occupies in the X-axis direction is also correspondingly longer.

  As described above, even if the opening of the concave portion 170 becomes long, the inclined surface 171b and the narrow width portion 142a correspond to each other at the position in the X-axis direction as in the first embodiment. For this reason, even when the pitch of the core part 14a and the core part 14b is narrowed, interference with the inclined surface 171b and the core part 14a can be prevented. That is, even when the formation density of the core portions 14 formed in the core layer 13 is increased, it is possible to ensure a sufficient area of the inclined surface 171b while avoiding interference between the inclined surface 171b and the core portion 14a. . Therefore, it is possible to achieve both high density of the core portion 14 and high optical coupling efficiency with an external optical component.

Moreover, when the lower surface of the core layer 13 is used as a reference surface, the angle formed by the reference surface and the inclined surface 172 ′ is preferably about 30 to 60 °, and more preferably about 40 to 50 °. Thereby, it becomes difficult to generate stress in the vicinity of the concave portion 170, and an increase in reflection loss of the inclined surface 171 due to stress concentration can be suppressed. The angle formed by the reference surface and the inclined surface 172 ′ refers to an inner angle formed on the side opposite to the concave portion 170 among the inner angle formed by the reference surface and the inclined surface 172 ′. .
In such a second embodiment, the same operations and effects as in the first embodiment can be obtained.

«Third embodiment»
Next, a third embodiment of the optical waveguide of the present invention will be described.

  8 and 9 are cross-sectional views showing a third embodiment of the optical waveguide of the present invention. 8 and 9, dots are given to the core portion.

  Hereinafter, the third embodiment will be described. In the following description, differences from the first and second embodiments will be mainly described, and description of similar matters will be omitted.

  The optical waveguide 1 according to the third embodiment is the same as the optical waveguide 1 according to the first and second embodiments, except that the formation position of the recess with respect to the core portion is different.

  That is, the concave portion 170 shown in FIG. 8 is formed at a position away from the right end of the core portion 14. For this reason, in the first and second embodiments, the core portion 14 is exposed on the inclined surface 171 of the concave portion 170, whereas in this embodiment, the side cladding formed so as to surround the right end of the core portion 14. The difference is that the portion 15 is exposed.

  In such an optical waveguide 1 shown in FIG. 8, the same operation and effect as the optical waveguide 1 according to the first and second embodiments can be obtained.

  In addition, in the first and second embodiments, both the core portion 14 and the side cladding portion 15 are exposed on the inclined surface 171, whereas in the present embodiment, only the side cladding portion 15 is exposed. Therefore, when the concave portion 170 is formed by various processing methods, the smooth inclined surface 171 can be easily formed. For this reason, it becomes possible to suppress the reflection loss of the inclined surface 171 smaller.

  On the other hand, the concave portion 170 shown in FIG. 9 is formed in the middle of the core portion 14. That is, in the first to third embodiments, the inclined surface 171 is formed on the extension line in the longitudinal direction of the core portion 14, whereas in the present embodiment, the inclined surface 171 is provided in the middle of the core portion 14 in the longitudinal direction. It differs in that it is formed.

  In the optical waveguide 1 shown in FIG. 9 as well, the same operations and effects as those of the optical waveguide 1 according to the first and second embodiments can be obtained.

<< Fourth Embodiment >>
Next, a fourth embodiment of the optical waveguide of the present invention will be described.

  FIG. 10 is a plan view showing a fourth embodiment of the optical waveguide of the present invention. In addition, in FIG. 10, the dot is attached | subjected with respect to the core part.

  Hereinafter, although 4th Embodiment is described, in the following description, it demonstrates centering around difference with 1st-3rd embodiment, The description is abbreviate | omitted about the same matter.

  The optical waveguide 1 according to the fourth embodiment is the same as the optical waveguide 1 according to the first to third embodiments except that the shape of the core portion 14 in plan view is different.

  That is, in the optical waveguide 1 according to the first embodiment, the planar view shape of the core portion 14 is a shape having a line-symmetric relationship with respect to an axis passing through the center of the width and parallel to the X axis. On the other hand, in the optical waveguide 1 according to the present embodiment, the planar view shape of the core portion 14 is different in that it is not line symmetric with respect to the axis.

  Specifically, in the present embodiment, the shape of the core portion 14 is set so as not to change the width in a portion of the core portion 14 that does not interfere with the inclined surface 171 of the adjacent core portion 14. . Therefore, the narrow part is not formed about the core part 14 which there is no possibility that the inclined surface 171 of the adjacent core part 14 may interfere. When the inclined surface 171 is close to the + Y side of the core portion 14 and the inclined surface 171 is not close to the −Y side, the outer edge shape of the core portion 14 on the + Y side is changed. On the other hand, the outer edge shape on the -Y side is not changed, and as a result, a narrow portion is formed. Since the planar view shape of the core portion 14 is set in such a pattern, in the optical waveguide 1 according to the present embodiment, the planar view shape of the core portion 14 includes a portion that is not line symmetric with respect to the axis. It is out.

  However, also in the optical waveguide 1 according to this embodiment, the same operations and effects as those of the optical waveguide 1 according to the first to third embodiments can be obtained.

«Fifth embodiment»
Next, a fifth embodiment of the optical waveguide of the present invention will be described.

  11 to 13 are plan views showing a fifth embodiment of the optical waveguide of the present invention. In addition, in FIGS. 11-13, the dot is attached | subjected with respect to the core part.

  Hereinafter, although 5th Embodiment is described, in the following description, it demonstrates centering around difference with 1st-4th embodiment, and the description is abbreviate | omitted about the same matter.

  The optical waveguide 1 according to the fifth embodiment is the same as the optical waveguide 1 according to the first to fourth embodiments except that the optical waveguide 1 has a through hole 18 provided in the vicinity of the recess 170.

  That is, the optical waveguide 1 shown in FIG. 11 has the through-hole 18 provided so as to overlap with the corner of the opening that forms the rectangle of the recess 170 in plan view. The through hole 18 has a circular shape in plan view, and penetrates the stacked body 10 in the thickness direction. By providing such a through hole 18, when stress is generated in the vicinity of the recess 170, it is possible to suppress an increase in reflection loss of the inclined surface 171 due to the stress.

  In addition, the through-hole 18 should just be provided so that it may overlap with at least one part among four corner | angular parts with which the rectangular opening part of the recessed part 170 is provided. For example, as shown in FIG. 11, through holes 18 are formed in four corners of the opening of the recess 170 including the inclined surface 171a, respectively, but the opening of the recess 170 including the inclined surface 171b is formed. The four corners provided are formed with through holes 18 so as to overlap only two corners located on the opposite side of the core portion 14a, and the remaining two corners are formed with through holes 18. Absent. Even in such a case, the above-described effects can be obtained.

  Further, the shape of the through-hole 18 in plan view is not limited to the perfect circle shown in FIG. 11, but is preferably a rounded shape such as an ellipse or an ellipse.

  The positional relationship between the opening of the recess 170 and the through hole 18 and the shape of the through hole 18 are not limited to those shown in FIG.

  For example, the optical waveguide 1 shown in FIG. 12A has a through hole 18 provided in the vicinity of the rectangular opening of the recess 170 in plan view and on the diagonal extension of the opening. The through hole 18 and the recess 170 are separated from each other. Moreover, the through-hole 18 shown to Fig.12 (a) has a perfect circle shape of the opening planar view similarly to the through-hole 18 shown in FIG.

  On the other hand, the optical waveguide 1 shown in FIG. 12B also has a through hole 18 provided in the vicinity of the rectangular opening of the recess 170 in plan view and on the diagonal extension of the opening. The through hole 18 and the recess 170 are separated from each other. In addition, the through hole 18 shown in FIG. 12B has an elliptical shape in the plan view of the opening, and is arranged so that its long axis and the extension line of the diagonal line are substantially orthogonal.

  Furthermore, the optical waveguide 1 shown in FIG. 12C also has a through hole 18 provided in the vicinity of the rectangular opening of the recess 170 in plan view and on the diagonal extension of the opening. The through hole 18 and the recess 170 are separated from each other. In addition, the through hole 18 shown in FIG. 12C has a linear opening shape in plan view, and is arranged so that the line segment and the extension line of the diagonal line are substantially orthogonal to each other.

  The optical waveguide 1 shown in FIG. 13 has a through hole 18 provided so as to connect the long side of the rectangular opening of the recess 170 in plan view and the outer edge of the optical waveguide 1. The through hole 18 shown in FIG. 13 has a linear shape in the plan view of the opening, and is arranged so that the line segment and the long side are substantially orthogonal.

  In the optical waveguide 1 shown in FIGS. 12 and 13 as described above, when stress is generated in the vicinity of the concave portion 170, it is possible to suppress an increase in reflection loss of the inclined surface 171 due to the stress.

  In addition, also in the optical waveguide 1 according to the present embodiment, the same operations and effects as those of the optical waveguide 1 according to the first to fourth embodiments can be obtained.

<< Sixth Embodiment >>
Next, a sixth embodiment of the optical waveguide of the present invention will be described.

  FIG. 14 is a plan view showing a sixth embodiment of the optical waveguide of the present invention. In FIG. 14, dots are added to the core portion.

  Hereinafter, although 6th Embodiment is described, in the following description, it demonstrates centering on difference with 1st-5th embodiment, and the description is abbreviate | omitted about the same matter.

  The optical waveguide 1 according to the sixth embodiment is formed of the above-described material that causes monomer diffusion, and has the monomer high concentration portion 19 provided in the vicinity of the concave portion 170. This is the same as the optical waveguide 1.

  That is, as described above, the optical waveguide 1 shown in FIG. 14 uses a material that generates monomer diffusion as a composition having a refractive index modulation ability, and irradiates members made of such a material with energy rays to The side clad portion 15 is formed. Such a member includes a polymer and a monomer having different refractive indexes, and for example, by irradiating an energy ray to a region where the side cladding portion 15 is to be formed, the monomer existing in that region is polymerized and non-irradiated. By inducing the migration of the monomer from the region, it is possible to form a monomer concentration difference and thus a refractive index difference. Therefore, it is possible to make a difference in the monomer concentration according to the irradiation amount of energy rays.

  The optical waveguide 1 according to the present embodiment includes a monomer high concentration portion 19 provided in the vicinity of an opening that forms a rectangle of the concave portion 170 in plan view and on an extension line of a diagonal line of the opening. The monomer high concentration portion 19 has a higher monomer concentration than the surrounding side cladding portion 15. Thereby, the local elastic modulus of the monomer high concentration part 19 is larger than the elastic modulus of the surrounding side cladding part 15. As a result, when stress is generated in the vicinity of the recess 170, it is possible to suppress an increase in reflection loss of the inclined surface 171 due to the stress.

  The monomer accumulated at a high concentration in the monomer high concentration portion 19 is polymerized in a subsequent process to become a monomer-derived polymer. Therefore, finally, in the monomer high concentration portion 19, the concentration of the polymer derived from the monomer that has moved based on the concentration difference is higher than that of the surrounding side cladding portion 15. The concentration of the “monomer-derived polymer” in the high monomer concentration portion 19 is preferably 10% by mass or more higher than the surrounding side cladding portion 15. Thereby, the effect mentioned above is exhibited more notably.

  Further, the planar view shape of the monomer high concentration portion 19 is not particularly limited, and in addition to the ellipse shown in FIG. 14, a circle such as a perfect circle or an ellipse, a polygon such as a triangle, a rectangle, a pentagon, or a hexagon. , Parallelogram, rhombus, and other irregular shapes.

  In addition, in the optical waveguide 1 according to the present embodiment, the same operations and effects as those of the optical waveguide 1 according to the first to fifth embodiments can be obtained.

<Opto-electric hybrid board and optical module>
Next, an embodiment of the opto-electric hybrid board of the present invention and an embodiment of the optical module of the present invention will be described.

  FIG. 15 is a longitudinal sectional view showing an embodiment of the opto-electric hybrid board of the present invention and an embodiment of the optical module of the present invention.

  An opto-electric hybrid board 100 shown in FIG. 15 has an optical waveguide 1, an electric wiring board 5 laminated thereon, and an adhesive layer 90 that is interposed between them and adheres them. Hereinafter, the configuration of each part of the opto-electric hybrid board 100 will be sequentially described.

  The optical waveguide 1 shown in FIG. 15 includes a support film 2 provided below the laminate 10 and a cover film 3 provided above the laminate 10 in addition to the laminate 10. By providing these films, the laminate 10 can be protected from the external environment and external force, and the reliability of the optical waveguide 1 can be further increased.

  Examples of the constituent material of the support film 2 and the cover film 3 include various resin materials such as polyethylene terephthalate (PET), polyolefin such as polyethylene and polypropylene, polyimide, and polyamide.

  Moreover, although the average thickness of the support film 2 and the cover film 3 is not specifically limited, It is preferable that it is about 5-500 micrometers, and it is more preferable that it is about 10-400 micrometers. Thereby, the laminated body 10 can be more reliably protected from external force and an external environment.

  The electrical wiring board 5 shown in FIG. 15 has a multilayer board 50 having a core board 51 and build-up layers 52 laminated on both surfaces thereof, and a through hole 53 penetrating the multilayer board 50. .

  Examples of the constituent material of the core substrate 51 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 a base material, and this base material is impregnated with a resin material such as a phenol resin, a polyester resin, an epoxy resin, a cyanate resin, a polyimide resin, or a fluorine resin. In addition to insulating substrates used for composite copper-clad laminates such as glass cloth / epoxy copper-clad laminates, glass nonwoven fabrics / epoxy copper-clad laminates, polyetherimide resin substrates, polyethers It may be a heat-resistant / thermoplastic organic rigid substrate such as a ketone resin substrate or a polysulfone resin substrate, or a ceramic rigid substrate such as an alumina substrate, an aluminum nitride substrate, or a silicon carbide substrate.

  The core substrate 51 is formed with through wirings that electrically connect the build-up layers 52 laminated on both surfaces thereof.

  On the other hand, the buildup layer 52 is formed by alternately laminating insulating layers 521 and conductor layers 522. The conductor layer 522 is patterned to form electrical wiring. Insulating layer 521 is formed with through wiring that connects the electrical wirings provided on both surfaces thereof.

  Each of the conductor layer 522 and the through wiring is made of a conductive material such as a simple metal such as copper, aluminum, nickel, chromium, zinc, tin, gold, silver, or an alloy containing these metal elements. .

  The insulating layer 521 is made of a silicon compound such as silicon oxide or silicon nitride, a resin material such as a polyimide resin or an epoxy resin, or the like.

  In this way, an electrical circuit that extends not only in the plane direction but also in the thickness direction can be constructed in the buildup layer 52, and the density of the electrical circuit can be increased.

  In addition, although such a multilayer substrate 50 may be formed by what kind of construction method, it is formed by various buildup construction methods, such as an additive method, a semi-additive method, and a subtractive method, as an example.

  The electrical wiring board provided in the opto-electric hybrid board of the present invention is not limited to the one including the multilayer board such as the electrical wiring board 5 described above. For example, the multilayer board is a single-layer electrical wiring board (rigid board). It may be replaced, or may be replaced with various flexible substrates such as a polyimide substrate, a polyester substrate, and an aramid film substrate. The multilayer substrate 50 can be replaced with a coreless multilayer substrate that does not include the core substrate 51. In the case of a flexible substrate, since the substrate itself has sufficient light transmittance, the through hole 53 that functions as an optical through hole may not be formed.

  Further, the electrical wiring substrate 5 shown in FIG. 1 has a solder resist layer 54 provided on the upper surface of the multilayer substrate 50. In the solder resist layer 54, an opening is formed at a connection portion with the conductor layer 522.

  The solder resist layer 54 is made of various resin materials and includes an inorganic filler as necessary. The average thickness of the solder resist layer 54 is not particularly limited, but is preferably about 10 to 100 μm, and more preferably about 20 to 50 μm.

  The optical / electrical hybrid substrate 100 is obtained by bonding the optical waveguide 1 and the electric wiring substrate 5 as described above through the adhesive layer 90.

  Also, by mounting the optical element 6 on the opto-electric hybrid board 100, an optical module (optical module of the present invention) 1000 is obtained. The optical element 6 shown in FIG. 15 has an element body 60, a light emitting / receiving portion 61 and a terminal 62 provided on the lower surface of the element body 60, and a bump 63 provided so as to protrude downward from the terminal 62. ing. The light emitting / receiving unit refers to a light receiving unit, a light emitting unit, or a unit having both functions.

  The optical element 6 is disposed such that the optical axis of the light emitting / receiving unit 61 and the optical axis of the core unit 14 coincide with each other via the inclined surface 171. Thereby, the optical waveguide 1 and the optical element 6 are optically connected, and the optical signal propagating through the optical waveguide 1 is received by the optical element 6, or the optical signal emitted from the optical element 6 is incident on the optical waveguide 1. You can do it.

  Further, the bump 63 is connected to the conductor layer 522. Thereby, the optical element 6 is mechanically fixed, the terminal 62 of the optical element 6 and the conductor layer 522 are electrically connected, and the operation of the optical element 6 can be controlled from the electric wiring board 5 side. Has been.

  Examples of the optical element 6 include a light emitting element such as a surface emitting laser (VCSEL), a light emitting diode (LED), and an organic EL element, and a light receiving element such as a photodiode (PD, APD).

  Further, an electric element (not shown) may be mounted on the opto-electric hybrid board 100 shown in FIG. Examples of the electric element include IC, LSI, RAM, ROM, capacitor, coil, resistor, and diode.

  Note that since the adhesive layer 90 is on the optical path, the adhesive layer 90 preferably has translucency. Examples of the constituent material of the adhesive layer 90 include resin materials such as an epoxy resin, an imide resin, a silicone resin, a phenol resin, and a urea resin.

  In such an opto-electric hybrid board 100 and the optical module 1000, the optical coupling efficiency can be increased when the light emitting / receiving unit 61 and the core unit 14 are optically connected via the inclined surface 171. Moreover, since the optical waveguide 1 has a high core capacity 14 and a large transmission capacity, the opto-electric hybrid board 100 and the optical module 1000 have a large communication capacity. Thereby, the fall of the S / N ratio in optical communication can be suppressed, and high-quality and large-capacity optical communication can be realized. Therefore, the opto-electric hybrid board 100 and the optical module 1000 are highly reliable.

<Electronic equipment>
The optical waveguide according to the present invention as described above has high optical coupling efficiency with respect to external optical components. For this reason, by providing the optical waveguide of the present invention, a highly reliable electronic device (electronic device of the present invention) capable of performing high-quality optical communication can be obtained.

  Examples of the electronic device including the optical waveguide of the present invention include electronic devices such as a mobile phone, a game machine, a router device, a WDM device, a personal computer, a television, and a home server. In any of these electronic devices, it is necessary to transmit a large amount of data at high speed between an arithmetic device such as an LSI and a storage device such as a RAM. Therefore, by providing such an electronic device with the optical waveguide of the present invention, problems such as noise and signal degradation peculiar to electric wiring are eliminated, and the performance of the electronic device is dramatically improved. It can contribute to cost reduction.

  In addition, the amount of heat generated in the optical waveguide portion is greatly reduced compared to electrical wiring. For this reason, the electric power required for cooling can be reduced and the power consumption of the whole electronic device can be reduced.

  The optical waveguide, the opto-electric hybrid board, the optical module, and the electronic device of the present invention have been described above. However, the present invention is not limited to this. For example, the optical waveguide and the opto-electric hybrid board according to each of the embodiments described above. In addition, an arbitrary component may be added to the optical module.

  Moreover, the embodiment of the optical waveguide of the present invention may be a combination of any two or more of the above embodiments.

Next, specific examples of the present invention will be described.
1. Optical waveguide manufacturing

Example 1
(1) Synthesis of norbornene-based resin In a glove box whose moisture and oxygen concentrations are both controlled to 1 ppm or less and filled with dry nitrogen, 7.2 g (40.1 mmol) of hexylnorbornene (HxNB), diphenylmethylnorbornenemethoxy 12.9 g (40.1 mmol) of silane was weighed into a 500 mL vial, 60 g of dehydrated toluene and 11 g of ethyl acetate were added, and the top was sealed with a silicon sealer.

  Next, 1.56 g (3.2 mmol) of Ni catalyst and 10 mL of dehydrated toluene were weighed in a 100 mL vial, and a stirrer chip was placed and sealed, and the catalyst was thoroughly stirred to dissolve completely.

  When 1 mL of this Ni catalyst solution was accurately weighed with a syringe, and quantitatively injected into the vial bottle in which the two kinds of norbornene were dissolved and stirred at room temperature for 1 hour, a marked increase in viscosity was confirmed. At this point, the stopper was removed, 60 g of tetrahydrofuran (THF) was added, and the mixture was stirred to obtain a reaction solution.

  In a 100 mL beaker, 9.5 g of acetic anhydride, 18 g of hydrogen peroxide (concentration 30%) and 30 g of ion-exchanged water were added and stirred to prepare an aqueous solution of peracetic acid on the spot. Next, the total amount of this aqueous solution was added to the above reaction solution and stirred for 12 hours to reduce Ni.

  Next, the treated reaction solution was transferred to a separatory funnel, the lower aqueous layer was removed, and then 100 mL of a 30% aqueous solution of isopropyl alcohol was added and vigorously stirred. The aqueous layer was removed after standing and completely separating the two layers. After repeating this water washing process three times in total, the oil layer was dropped into a large excess of acetone to reprecipitate the polymer produced and separated from the filtrate by filtration, and then in a vacuum dryer set at 60 ° C. Polymer # 1 was obtained by heating and drying for 12 hours. The molecular weight distribution of the polymer # 1 was Mw = 100,000 and Mn = 40,000 by GPC measurement. The molar ratio of each structural unit in polymer # 1 was 50 mol% for the hexylnorbornene structural unit and 50 mol% for the diphenylmethylnorbornenemethoxysilane structural unit, as determined by NMR.

(2) Production of composition for forming core layer 10 g of the above-mentioned polymer # 1 was weighed into a 100 mL glass container, and 40 g of mesitylene, 0.01 g of antioxidant Irganox 1076 (manufactured by Ciba Geigy), cyclohexyloxetane monomer (Toa) Synthetic CHOX, CAS # 483303-3-25-9, molecular weight 186, boiling point 125 ° C./1.33 kPa) 2 g, polymerization initiator (photoacid generator) Rhosilsil Photoinitiator 2074 (manufactured by Rhodia, CAS # 178233-72-2) 0.025 g in 0.1 mL of ethyl acetate) was added and dissolved uniformly, and then filtered through a 0.2 μm PTFE filter to obtain a clean composition for forming a core layer.

(3) Manufacture of the composition for forming a clad layer The molar ratio of each structural unit of the purified polymer # 1 was changed to hexylnorbornene structural unit 80 mol% and diphenylmethylnorbornenemethoxysilane structural unit 20 mol%, respectively. A cladding layer forming composition was obtained in the same manner as the core layer forming composition except that it was used in place of polymer # 1.

(4) Production of first clad layer The clad layer-forming composition produced in (3) was uniformly applied with a doctor blade on the base film on which the release layer was formed, and then applied to a dryer at 50 ° C. Added for a minute. After completely removing the solvent, the entire surface was irradiated with UV light by a UV exposure machine to cure the applied composition. As a result, a colorless and transparent first cladding layer having a thickness of 10 μm was obtained. The cumulative amount of ultraviolet light was 500 mJ / cm ² .

(5) Preparation of core layer After apply | coating a core layer resin composition uniformly with a doctor blade on the base film in which the mold release layer was formed, it injected | threw-in to the dryer of 50 degreeC for 10 minutes. After completely removing the solvent to form a film, a photomask having a linear pattern of lines and spaces drawn on the entire surface was pressure-bonded onto the obtained film. Then, ultraviolet rays were irradiated from above the photomask with a parallel exposure machine. The integrated light quantity of ultraviolet rays was 1300 mJ / cm ² .

  Next, the photomask was removed and placed in an oven at 150 ° C. for 30 minutes. Upon removal from the oven, it was confirmed that a clear waveguide pattern appeared on the coating. Moreover, the thickness of the obtained core part was 50 micrometers, and the number of the core parts was eight. The pitch P of the core part is as shown in Table 1.

  In addition, the wide part and the narrow part were formed in the core part. The width W1 of the wide portion and the width W2 of the narrow portion are as shown in Table 1, respectively.

(6) Preparation of second clad layer On the base film on which the release layer is formed, a clad layer forming composition is applied in the same manner as in (4), and a colorless and transparent second clad layer having a thickness of 10 μm is formed. Obtained.

(7) Manufacture of laminated body Next, a core layer was stacked on the first cladding layer. Then, the base film attached to the core layer was peeled off.

  Next, the second cladding layer was overlaid on the core layer. Then, the base film attached to the second cladding layer was peeled off.

  Thereafter, the first cladding layer, the core layer, and the second cladding layer were pressurized, and the layers were pressure-bonded to each other. This obtained the laminated body.

(8) Formation of recessed part Next, the recessed part was formed in the both ends of the core part by laser processing, respectively. Thereby, an optical waveguide having a total length of 10 cm was obtained. In addition, the shape of the formed recessed part is as showing to FIGS. Further, the shortest distance S between the core portion and the recess formed at the end of the core portion adjacent to the core portion is as shown in Table 1. Furthermore, the width of the recess (inclined surface) is as shown in Table 1.

(Examples 2 to 4)
In the production of the core layer, the optical waveguide was changed in the same manner as in Example 1 except that the photomask used for irradiating the ultraviolet rays was changed and the shape of the core part and the arrangement of the recesses were changed as shown in Table 1. Obtained.

(Example 5)
Optical waveguides were obtained in the same manner as in Example 2 except that the shape of the formed recesses was changed as shown in FIGS. 5 to 7 and the manufacturing conditions were changed as shown in Table 1.

(Example 6)
An optical waveguide was obtained in the same manner as in Example 2 except that a through hole as shown in FIG. 11 was further formed.

(Example 7)
An optical waveguide was obtained in the same manner as in Example 2 except that a through hole as shown in FIG.

(Example 8)
An optical waveguide was obtained in the same manner as in Example 2 except that a through hole as shown in FIG.

Example 9
An optical waveguide was obtained in the same manner as in Example 2 except that a through hole as shown in FIG.

(Example 10)
An optical waveguide was obtained in the same manner as in Example 2 except that a through hole as shown in FIG. 13 was further formed.

(Example 11)
An optical waveguide was obtained in the same manner as in Example 2 except that a monomer high concentration portion as shown in FIG. 14 was further formed.

(Example 12)
(1) Production of Cladding Layer Forming Resin Composition Daicel Chemical Industries, Ltd. Alicyclic Epoxy Resin, Celoxide 2081 20 g, ADEKA Co., Ltd. Cationic Polymerization Initiator, Adekaoptomer SP-170 0.6 g A solution was prepared by stirring and mixing 80 g of methyl isobutyl ketone.

  Subsequently, the obtained solution was filtered with a PTFE filter having a pore size of 0.2 μm to obtain a clean and colorless and transparent resin composition for forming a cladding layer.

(2) Manufacture of photosensitive resin composition As an epoxy polymer, phenoxy resin manufactured by Nippon Steel Chemical Co., Ltd., 20 g of YP-50S, 5 g of Celoxide 2021P manufactured by Daicel Chemical Industries, Ltd. as a photopolymerizable monomer, and polymerization As an initiator, 0.2 g of Adekaoptomer SP-170 manufactured by ADEKA Corporation was put into 80 g of methyl isobutyl ketone, and dissolved by stirring to prepare a solution.

  Subsequently, the obtained solution was filtered with a PTFE filter having a pore size of 0.2 μm to obtain a clean, colorless and transparent photosensitive resin composition.

(3) Production of lower clad layer The clad layer-forming resin composition was uniformly applied onto a polyimide film having a thickness of 25 µm by a doctor blade, and then placed in a dryer at 50 ° C for 10 minutes. After the solvent was completely removed, the entire surface was irradiated with ultraviolet rays with a UV exposure machine to cure the applied resin composition. As a result, a colorless and transparent lower cladding layer having a thickness of 10 μm was obtained. The cumulative amount of ultraviolet light was 500 mJ / cm ² .

(4) Production of core layer The photosensitive resin composition was uniformly applied by a doctor blade on the produced lower clad layer, and then placed in a dryer at 40 ° C for 5 minutes. After completely removing the solvent to form a film, ultraviolet rays were irradiated by a maskless exposure apparatus so as to draw a linear pattern of lines and spaces on the obtained film. The cumulative amount of ultraviolet light was 1000 mJ / cm ² .

  Next, the exposed film was placed in an oven at 150 ° C. for 30 minutes. Upon removal from the oven, it was confirmed that a plurality of clear waveguide patterns appeared on the coating. Moreover, the thickness of the obtained core part was 50 micrometers, and the number of the core parts was eight. Further, the pitch P of the core portion is as shown in Table 2.

  In addition, the wide part and the narrow part were formed in the core part. The width W1 of the wide portion and the width W2 of the narrow portion are as shown in Table 2, respectively.

(5) Production of upper clad layer A clad layer-forming resin composition was applied to the produced core layer in the same manner as in (3) to obtain a colorless and transparent upper clad layer having a thickness of 10 μm.

(6) Formation of recessed part Next, the recessed part was formed in the both ends of the core part by laser processing, respectively. Thereby, an optical waveguide having a total length of 10 cm was obtained. In addition, the shape of the formed recessed part is as showing to FIGS. Further, the shortest distance S between the core portion and the concave portion formed at the end portion of the core portion adjacent to the core portion is as shown in Table 2. Furthermore, the width of the recess (inclined surface) is as shown in Table 2.

(Example 13)
An optical waveguide was obtained in the same manner as in Example 12 except that the shape of the formed recess was changed as shown in FIGS. 5 to 7 and the manufacturing conditions were changed as shown in Table 2.

(Comparative Example 1)
In the same manner as in Example 12, except that the narrow width portion is not formed in the core portion and the width of the concave portion is narrowed so that the core portion and the concave portion (inclined surface) do not interfere with each other. Got.

(Comparative Example 2)
In the same manner as in Example 13, except that the narrow width portion is not formed in the core portion and the width of the concave portion is narrowed so that the core portion and the concave portion (inclined surface) do not interfere with each other. Got.

2. 2. Evaluation of Optical Waveguide 2.1 Evaluation of Insertion Loss and Mirror Loss Regarding the optical waveguides obtained in each Example and each Comparative Example, “Testing Method for Polymer Optical Waveguide (JPCA- The insertion loss of the optical path through the inclined surface (mirror) was measured in accordance with the measurement method of 4.6.1 insertion loss of “PE02-05-01S-2008)”.

  Next, the optical propagation loss (transmission loss) is measured for the optical waveguides obtained in each of the examples and the comparative examples in accordance with the method for measuring the optical propagation loss per unit length of 4.6.2 in the above test method. did.

  As a result, it was confirmed that the optical propagation loss was almost the same in each of the optical waveguides obtained in each example and each comparative example.

  Since the insertion loss of the optical waveguide is considered to be the sum of the light propagation loss and the mirror loss, the mirror loss was obtained for the optical waveguides obtained in the respective examples and the comparative examples. The obtained mirror loss was evaluated according to the following evaluation criteria.

<Evaluation criteria for mirror loss>
A: Mirror loss is very small (less than 0.2 dB)
B: Mirror loss is small (0.2 dB or more and less than 0.5 dB)
C: Mirror loss is slightly small (0.5 dB or more and less than 1.0 dB)
D: Mirror loss is slightly large (1.0 dB or more and less than 1.5 dB)
E: Large mirror loss (1.5 dB or more and less than 2 dB)
F: Very large mirror loss (2 dB or more)
The above evaluation results are shown in Tables 1 and 2.

2.2 Evaluation of durability against temperature The optical waveguides obtained in each of Examples and Comparative Examples were subjected to a temperature cycle test. The test conditions of the temperature cycle test are as shown below.

<Test conditions for temperature cycle test>
・ Temperature: -40 to 125 ° C
・ Number of cycles: 500 cycles (30 minutes each for high temperature and low temperature)
・ Evaluation characteristics: Insertion loss

  Next, the insertion loss was compared before and after the test. And the increment of the insertion loss after a test was evaluated according to the following evaluation criteria. In addition, when the optical propagation loss per unit length was measured for the specimen after the test, there was almost no change from before the test, so most of the increase in insertion loss is considered to be due to an increase in mirror loss. It is done.

<Evaluation criteria for increment of insertion loss by temperature cycle test>
A: The increment is very small (less than 0.2 dB)
B: Small increment (0.2 dB or more and less than 0.5 dB)
C: Increment is slightly small (0.5 dB or more and less than 1.0 dB)
D: Slightly large increment (1.0 dB or more and less than 1.5 dB)
E: The increment is large (1.5 dB or more and less than 2 dB)
F: The increment is very large (2 dB or more)
The above evaluation results are shown in Tables 1 and 2.

  As is apparent from Tables 1 and 2, the optical waveguides obtained in the respective examples have relatively small mirror loss even when the core portion pitch P is sufficiently small (for example, 100 μm or less), and the temperature It was found that the amount of increase in mirror loss was relatively small even after exposure to harsh environments such as cycle tests.

  On the other hand, it was confirmed that the optical waveguides obtained in Comparative Examples 1 and 2 have a relatively large mirror loss. In consideration of interference with the core portion, the width of the concave portion (inclined surface) has to be narrower than that in the second embodiment, so that the effective area for light reflection is relatively smaller than that in the second embodiment. This is considered to be the cause. Moreover, it is guessed that durability with respect to a temperature cycling test also fell somewhat because the effective area was small.

DESCRIPTION OF SYMBOLS 1 Optical waveguide 2 Support film 3 Cover film 5 Electrical wiring board 6 Optical element 10 Laminated body 11 Clad layer 12 Clad layer 13 Core layer 14 Core part 14a Core part 14b Core part 15 Side surface clad part 18 Through-hole 19 Monomer high concentration part 50 Multilayer substrate 51 Core substrate 52 Build-up layer 53 Through-hole 54 Solder resist layer 60 Element body 61 Light emitting / receiving unit 62 Terminal 63 Bump 90 Adhesive layer 100 Opto-electric hybrid board 140a Optical path 140b Optical path 141a Wide part 141b Wide part 142a Narrow part 142b Narrow part 143a Wide part 143b Wide part 144a Wide part 144b Wide part 170 Recess 171 Inclined surface 171a Inclined surface 171b Inclined surface 172 Upright surface 172 ′ Inclined surface 173 Upright surface 174 Upright surface 521 Insulating layer 522 Conductive layer 1000 Optical module L Virtual line P Pitch The shortest distance

Claims (8)

A first core portion and a second core portion extending in the X-axis direction and arranged in the Y-axis direction intersecting the X-axis direction;
A first mirror having a width wider than that of the first core portion provided in the middle of the longitudinal direction of the first core portion or on an extension line, and converts a first optical path extending from the first mirror to the −X side. A first mirror that
A second mirror having a width wider than that of the second core portion provided on the middle of the longitudinal direction of the second core portion or on an extension line so as to be shifted to the −X side with respect to the first mirror, A second mirror for converting a second optical path extending from the mirror to the -X side;
Have
The first core part includes a wide part, a first variable width part gradually changing in width so as to be narrower than the wide part, a narrow part having a narrower width than the wide part, and the narrow part A second variable width portion whose width gradually changes so as to be wider than the first portion, in this order, and the second mirror and the narrow width portion correspond to each other at the position in the X-axis direction. An optical waveguide characterized by   The optical waveguide according to claim 1, wherein the virtual line and the second mirror are configured to overlap each other when a virtual line that virtually extends the outer edge of the wide portion is drawn. 3. The optical waveguide according to claim 1, wherein the shape of the first core portion in plan view is a shape having a line-symmetric relationship with respect to an axis that passes through the center of the width and is parallel to the X axis .   The width of the first mirror and the width of the second mirror are each larger than the distance between the center of the width of the first core part and the center of the width of the second core part, and narrower than twice the distance. Item 4. The optical waveguide according to any one of Items 1 to 3.   The said 1st core part and the said 2nd core part are formed by irradiating an energy ray with respect to the member which can respectively change a refractive index by irradiation of an energy ray. The optical waveguide according to claim 1.   An opto-electric hybrid board comprising the optical waveguide according to claim 1.   An optical module comprising the opto-electric hybrid board according to claim 6 and an optical element.   An electronic apparatus comprising the optical waveguide according to any one of claims 1 to 5.

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