JP2016102883A - Optical waveguide, manufacturing method of optical waveguide module, and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical waveguide which includes formation lines capable of recognizing their positions more accurately than ever before so as to be able to function as alignment marks, and a manufacturing method of an optical waveguide module using the optical waveguide.SOLUTION: An optical waveguide 1 includes a core layer 11 including a long core part 111, and waveguide pattern formation lines 113. Average values of a refractive index in a thickness direction of the core layer 11 change in a line width direction of the waveguide pattern formation lines 113, so that the waveguide pattern formation lines 113 are formed. A difference in the average values of the refractive index in the thickness direction at both end parts in the line width direction of the waveguide pattern formation lines 113 is a range in which the waveguide pattern formation lines 113 function as alignment marks.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an optical waveguide, a method for manufacturing an optical waveguide module, and an electronic device.

  Conventionally, in an optical communication technology for transferring data using an optical carrier wave, an optical waveguide is known as a means for guiding the optical carrier wave from one point to another point. This optical waveguide has a long core part and a clad part provided so as to cover the periphery thereof. The core portion is made of a material that is substantially transparent to the optical carrier wave. The cladding part is made of a material having a lower refractive index than the core part.

  In the optical waveguide, light introduced from one end of the core portion is propagated to the other end while being reflected at the boundary between the core portion and the clad 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 and is received by the light receiving element, and optical communication is performed based on the flickering pattern of the received light or its intensity pattern.

  By the way, an optical waveguide is generally used for short-distance optical communication, and an optical fiber is used for long-distance optical communication. Therefore, when connecting the local network and the backbone network, it is necessary to optically connect the optical waveguide and the optical fiber.

  For example, FIG. 8 of Patent Document 1 discloses a structure in which an optical waveguide and an optical fiber are connected. In this structure, an optical fiber is disposed above an optical waveguide in which an optical path conversion mirror is formed, and the optical fiber is optically connected to the optical waveguide via an optical connector.

  More specifically, the optical fiber is optically connected to the optical waveguide by fitting a guide pin formed on the lower surface of the optical connector connected to the optical fiber into a guide hole formed on the upper surface of the optical waveguide. At this time, since it is necessary for the optical axis of the optical waveguide and the optical axis of the optical fiber to coincide with each other via a mirror, the positional accuracy of the guide hole formed in the upper surface of the optical waveguide is extremely important. Similarly, the positional accuracy of the mirror processed and formed in the optical waveguide is extremely important.

  By the way, when processing and forming guide holes and mirrors in the optical waveguide, a core portion provided in the optical waveguide has been used as a reference point for these processing positions. However, since the core part is a very thin line, it is difficult to accurately recognize its position. Therefore, when the core portion is used as a reference point, there is a problem that the position accuracy of the guide hole and the mirror cannot be sufficiently increased as a result of the position of the reference point being unstable.

International Publication No. 2006/054569

  Therefore, it has been proposed to provide an alignment mark on the optical waveguide and use this as a reference point. However, in the case of an alignment mark whose position cannot be accurately recognized, it cannot function sufficiently as an alignment mark, and the same problem as in the case where the core portion is used as a reference point has occurred.

  An object of the present invention is to provide an optical waveguide provided with a forming line that can recognize its position more accurately and function as an alignment mark, and a method for manufacturing an optical waveguide module using the optical waveguide.

  (1) An optical waveguide provided with a core layer (for example, a core layer 11 to be described later) having a long core portion (for example, a core portion 111 to be described later) having a refractive index in the thickness direction of the core layer. A formation line (for example, a waveguide pattern formation line 113 described later) formed by changing the average value in the line width direction is provided, and both end portions (for example, both end portions P1 described later) of the formation line in the line width direction are provided. , P2), an optical waveguide in which the formation line functions as an alignment mark (for example, optical waveguide 1 described later).

  (2) The optical waveguide according to (1), wherein the difference between the average values is 0.01 to 0.05.

  (3) The optical waveguide according to (1) or (2), wherein the formed line has a line width of 1 to 7 μm.

  (4) The optical waveguide according to any one of (1) to (3), wherein a width of the core portion is 20 to 100 μm, and a height of the core portion is 20 to 100 μm.

  (5) The optical waveguide according to any one of (1) to (4), wherein a pitch, which is a distance between the central axes of the adjacent core portions, is 50 to 500 μm.

  (6) A core layer (e.g., described later) having a long core (e.g., core unit 111 described later) and a cladding part (e.g., side cladding unit 112 described later) adjacent to the side surface of the core unit. An optical waveguide provided with at least one of an inclined surface and a curved surface functioning as a forming line as an alignment mark at the interface between the core portion and the cladding portion (for example, described later) Optical waveguide 1).

  (7) A method of manufacturing an optical waveguide module using the optical waveguide according to any one of (1) to (6) (for example, an optical waveguide 1 described later), wherein the formation line (for example, a waveguide pattern described later) A manufacturing method of an optical waveguide module including a processing step of determining a processing position on the basis of the position of the forming line 113) and processing the optical waveguide.

  (8) An electronic device including the optical waveguide according to any one of (1) to (6) (for example, an optical waveguide 1 described later).

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the optical waveguide provided with the formation line which can recognize the position more correctly than before, and can function as an alignment mark, and this optical waveguide can be provided. In addition, according to the present invention, various processing can be performed on the optical waveguide with high positional accuracy.

It is a perspective view showing some optical waveguides concerning one embodiment of the present invention. It is a figure which shows the relationship between the average value of the refractive index of the thickness direction, and a waveguide pattern formation line in case the refractive index distribution in the cross section of the core part which concerns on the said embodiment is SI type. It is a figure which shows the relationship between the alignment mark formation line and a cross-sectional shape in an alignment mark whose refractive index distribution in a cross-section is SI type. It is a figure which shows the relationship between the average value of the refractive index of the thickness direction, and a waveguide pattern formation line in case the refractive index distribution in the cross section of the core part which concerns on the said embodiment is a W type. It is a figure which shows an example of the process of the optical waveguide which concerns on the said embodiment.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
[Optical waveguide]
FIG. 1 is a perspective view showing a part of an optical waveguide 1 according to an embodiment of the present invention. As shown in FIG. 1, the optical waveguide 1 has a band shape and functions as an optical wiring that transmits an optical signal from one end to the other end. The optical waveguide 1 includes a core layer 11, a lower clad layer 12, and an upper clad layer 13, and is formed by laminating the lower clad layer 12, the core layer 11, and the upper clad layer 13 in this order from below. Is done.

  In addition, the optical waveguide 1 according to the present embodiment includes a plurality of waveguide pattern forming lines 113 constituting the outline of a waveguide pattern formed by a core part 111 and a side cladding part 112 described later in plan view. The waveguide pattern forming line 113 can be accurately recognized by, for example, an image recognition system in a plan view of the optical waveguide 1 and can function as an alignment mark. Therefore, various processing can be performed with high positional accuracy with respect to the optical waveguide 1 with reference to the position of the waveguide pattern forming line 113. The waveguide pattern forming line 113 will be described in detail later.

  First, the basic configuration of the optical waveguide 1 will be described in detail.

  The core layer 11 includes a plurality of long core portions 111 provided in parallel and a plurality of side clad portions 112 provided adjacent to both side surfaces of each core portion 111. That is, the side clad portion 112 is provided in the core layer 11 so as to fill a space between the plurality of core portions 111. The side clad portion 112 is formed of a member having a refractive index lower than that of the core portion 111, similarly to the lower clad layer 12 and the upper clad layer 13 described later. Thereby, in each core part 111 surrounded by the side clad part 112, the lower clad layer 12, and the upper clad layer 13 (hereinafter, these clads are simply referred to as “clad parts”), the light introduced from one end thereof. Are confined in each core part 111, and the confined light is propagated to the other end while being reflected at the boundary with the clad part.

  The refractive index of the core part 111 is set larger than the refractive index of the cladding part, and the difference is preferably 0.3% or more, more preferably 0.5% or more. The upper limit is preferably 5.5% or less. When the difference in refractive index is less than 0.3%, the effect of propagating light may be reduced. On the other hand, when the refractive index difference exceeds 5.5%, further improvement in the light propagation efficiency cannot be expected.

The above refractive index difference is expressed by the following equation (1), where A is the refractive index of the core 111 and B is the refractive index of the cladding.
[Equation 1]

Refractive index difference (%) = | A / B-1 | × 100 (1)

Further, the refractive index distribution in the cross section of the core portion 111 (the cross section in the direction orthogonal to the extending direction of the core portion 111; the same applies hereinafter) may be any shape distribution. Specifically, it may be a so-called step index (SI) type distribution in which the refractive index changes discontinuously, a so-called graded index (GI) type distribution in which the refractive index changes continuously, or a W type distribution. There may be. The SI type distribution is easy to form because the refractive index distribution is formed from different materials. In the case of the GI type distribution, the probability that the signal light is collected in a region having a high refractive index is increased, so that the propagation efficiency is improved. Further, in the case of the W-type distribution, the probability that the signal light is collected in a region having a high refractive index is increased as in the GI-type distribution, so that the propagation efficiency is improved and the crosstalk can be further suppressed because the light hardly leaks.

  The GI type distribution and the W type distribution include a high refractive index region including a maximum value and a low refractive index region having a refractive index lower than that of the high refractive index region, and at least partially or entirely. The refractive index changes continuously. In the GI type distribution, there is a region where the refractive index is constant in the low refractive index region, whereas in the W type distribution, as disclosed in, for example, Japanese Patent Application Laid-Open No. 2012-123254, the low refractive index region is low. Even in the refractive index region, the refractive index continuously changes and changes in a W shape as a whole. With such a refractive index distribution, the core layer 111 is positioned in the core layer 11 corresponding to the high refractive index region, and the side clad portion 112 is positioned corresponding to the low refractive index region.

  In FIG. 1, only the two core portions 111 are shown. However, the number of the core portions 111 is preferably 2 to 100, more preferably 2 to 50, as the entire optical waveguide 1. When the number of core portions 111 is large, the optical waveguide 1 may be multilayered as necessary. Specifically, the optical waveguide 1 shown in FIG. 1 may be multilayered by alternately stacking core layers and cladding layers.

  Moreover, in FIG. 1, the linear core part 111 was shown by planar view, However, It is not limited to this, A curved shape may be sufficient. Moreover, the core part 111 may cross | intersect in the middle and may branch.

  Moreover, although the cross-sectional shape of the core part 111 showed the rectangular shape in FIG. 1, taper shape (trapezoid shape) may be sufficient, for example. The cross-sectional shape of the core part 111 will be described in detail later.

  Next, the waveguide pattern forming line 113 will be described in detail.

  As described above, the optical waveguide 1 according to this embodiment includes the plurality of waveguide pattern forming lines 113 that form the outline of the waveguide pattern formed by the core part 111 and the side cladding part 112. The waveguide pattern forming line 113 is formed by changing the average value of the refractive index in the thickness direction of the core layer 11 in the line width direction. That is, the waveguide pattern forming line 113 exhibits a color different from that of the adjacent core part 111 and the side cladding part 112 when the average value of the refractive index in the thickness direction of the core layer 11 changes in the line width direction. . For example, when the planar image is binarized by an image recognition system, the waveguide pattern forming line 113 is recognized as blacker than the adjacent core part 111 and side cladding part 112. Therefore, the position of the waveguide pattern forming line 113 can be accurately recognized by an image recognition system or the like in plan view of the optical waveguide 1.

  Since the waveguide pattern forming line 113 is formed in the core layer 11, when the waveguide pattern forming line 113 is recognized by an image recognition system or the like, the upper clad layer 13 laminated on the core layer 11 or the core layer 11. It will be recognized through the lower clad layer 12 laminated below. Therefore, depending on the external environment, it may be difficult to recognize due to the influence of reflection and scattering of external light. However, the waveguide pattern forming line 113 of the present embodiment may be used by an image recognition system or the like even under such an environment. The position can be accurately recognized and can sufficiently function as an alignment mark.

  More specifically, in the waveguide pattern forming line 113, the difference in the average refractive index in the thickness direction (the thickness direction of the core layer 11; the same applies hereinafter) at both ends in the line width direction is the waveguide pattern forming line 113. Is set in a range that functions as an alignment mark.

  Here, the range functioning as an alignment mark means a range in which the position of the waveguide pattern forming line 113 can be accurately recognized by an image recognition system described later and high processing accuracy can be obtained.

  Specifically, the difference in the average refractive index in the thickness direction (thickness direction of the core layer 11; the same applies hereinafter) at both ends in the line width direction of the waveguide pattern forming line 113 is 0.01 to 0.05. Is preferably set, and more preferably 0.02 to 0.04. Thereby, the waveguide pattern forming line 113 can be accurately recognized by an image recognition system or the like, and functions sufficiently as an alignment mark.

  The average value of the refractive index in the thickness direction of the core layer 11 is obtained by measuring the refractive index at predetermined intervals in the thickness direction of the core layer 11 in the cross section of the core layer 11 and integrating the obtained measured values. Can be obtained by calculating. Specifically, for example, it can be obtained by setting 10 measurement points at equal intervals in the thickness direction of the core layer, measuring and integrating the refractive index at each measurement point, and then calculating an average value.

  In addition, as a refractive index measuring apparatus, conventionally well-known apparatuses, such as a laser interference microscope, can be used.

  Further, both end portions in the line width direction of the waveguide pattern forming line 113 mean both end portions in the line width direction in a plan view of the waveguide pattern forming line 113 recognized by the image recognition system described later.

  Note that a pattern matching method and an edge detection method, which will be described later, are employed as the image recognition system. The position of the waveguide pattern forming line 113 of this embodiment can be accurately recognized by any method.

  In the image recognition system, the position and shape of the waveguide pattern forming line 113 are usually recognized by imaging the optical waveguide 1 with an imaging device (for example, CCD, CMOS, etc.) in plan view and processing the captured image. The

  As an image pickup apparatus of the image recognition system, an image pickup apparatus including an optical lens having a numerical aperture (NA) of 0.4 or less is preferably used.

  Here, FIG. 2 is a diagram showing the relationship between the average value of the refractive index in the thickness direction and the waveguide pattern forming line 113 when the refractive index distribution in the cross section of the core portion 111 is the SI type. More specifically, the upper part of FIG. 2 shows the waveguide pattern forming line 113 in plan view, the middle part shows the cross-sectional shape of the core part 111, and the lower part shows the average value of the refractive index in the thickness direction. Yes.

  As shown in the middle part of FIG. 2, the core part 111 whose refractive index distribution in the cross section is the SI type is formed by exposure or etching, and then the side cladding part 112 is formed of a material different from that of the core part 111. Therefore, the cross-sectional shape is not a rectangular shape but actually a tapered shape (trapezoidal shape). That is, in the SI type, the boundary surface between the core portion 111 and the side cladding portion 112 is an inclined surface.

  Therefore, in the SI type, since the refractive index changes discontinuously at the boundary between the core portion 111 and the side cladding portion 112, as shown in the lower stage of FIG. Tapered (trapezoidal).

  Further, it can be seen that the position in the width direction of the waveguide pattern forming line 113 shown in the upper part of FIG. 2 corresponds to a part of the inclined portion in the tapered distribution of the average value of the refractive index in the thickness direction. That is, it can be seen that the positions in the width direction of both end portions P1 and P2 in the line width direction of the waveguide pattern forming line 113 are located in the inclined portions in the tapered distribution of the average value of the refractive index in the thickness direction.

  The difference in the average value of the refractive index in the thickness direction at both ends P1, P2 in the line width direction of the waveguide pattern forming line 113 is the difference between R2 and R1 shown in the lower part of FIG. Therefore, in this embodiment, the difference between R2 and R1 is set within the above-described range of 0.01 to 0.05, so that the waveguide pattern forming line 113 is accurately recognized by the image recognition system or the like. And can function sufficiently as an alignment mark.

  As described above, when the refractive index distribution in the cross section is the SI type, an inclined surface or curved surface capable of functioning the waveguide pattern forming line 113 as an alignment mark is formed at the interface between the core portion 111 and the side cladding portion 112. It means that it is important to provide.

  The difference between R2 and R1 is that the cross-sectional shape of the core part 111 is changed by changing the constituent material of the core part 111 and the constituent material of the side cladding part 112, or by changing the exposure conditions, development conditions, etching conditions, etc. It can be adjusted by adjusting.

  By the way, when forming an alignment mark on the core layer 11, the alignment mark is formed by a manufacturing method similar to the manufacturing method of the core part 111 described later, using the same material as the material of the core part 111 described later. Specifically, by performing exposure or the like, the refractive index of the core layer 11 is changed relative to the side cladding portion 112 by changing a partial refractive index of the core layer 11 or by changing a partial composition. A high alignment mark is formed. That is, the composition of the alignment mark and the core part 111 is the same. Similarly, the plurality of waveguide pattern forming lines 113 constituting the outline of the waveguide pattern formed by the core part 111 and the side clad part 112 and the alignment mark forming lines constituting the outline of the alignment mark are the same. It is. Therefore, the above-mentioned definition of the difference in the average value of the refractive index in the thickness direction at both ends in the line width direction of the waveguide pattern forming line 113 can also be applied to the alignment mark forming line.

  FIG. 3 is a diagram showing a relationship between an alignment mark formation line and a cross-sectional shape in an alignment mark whose refractive index distribution in the cross-section is an SI type. More specifically, in FIGS. 3A to 3C, alignment mark formation lines are shown in each upper stage, and the cross-sectional shape of the alignment mark is shown in each lower stage. In FIG. 3, a perfect alignment mark is shown as an example in plan view.

  As described above, when the refractive index distribution in the cross section is the SI type, if the cross sectional shape of the core part 111 is tapered, the distribution of the average value of the refractive index in the thickness direction is also tapered. That is, there is a correlation between the cross-sectional shape and the distribution shape of the average refractive index in the thickness direction, and the same can be said for the SI type alignment mark.

  Therefore, as shown in FIG. 3A, when the cross-sectional shape of the alignment mark 114a is rectangular, that is, when the average refractive index distribution in the thickness direction is also rectangular, the alignment mark forming line The line width is thin and it is difficult to get contrast with the surroundings. Therefore, the position cannot be accurately recognized by an image recognition system or the like, and high position accuracy cannot be obtained.

  On the other hand, as shown in FIG. 3B, when the cross-sectional shape of the alignment mark 114b is a moderately tapered shape, that is, the distribution of the average refractive index in the thickness direction is also a moderately tapered shape. In the case of the shape, the line width of the alignment mark forming line becomes an appropriate thickness, and the contrast with the surroundings is easily added. Therefore, the position can be accurately recognized by an image recognition system or the like, and high position accuracy can be obtained.

  On the other hand, as shown in FIG. 3C, when the cross-sectional shape of the alignment mark 114c is a gently inclined tapered shape, that is, when the distribution of the average value of the refractive index in the thickness direction is also a gently inclined tapered shape. In some cases, the line width of the alignment mark forming line becomes too thick. For this reason, it is difficult to accurately recognize the position by an image recognition system or the like, and it is difficult to obtain high position accuracy.

  From the above, it is preferable that the line width L (see FIG. 2) of the waveguide pattern forming line 113 is within a predetermined range as well as the alignment mark forming line. Specifically, the line width L of the waveguide pattern forming line 113 is preferably 1 μm to 7 μm, and more preferably 2 μm to 5 μm. Thereby, the position of the waveguide pattern forming line 113 can be accurately recognized by an image recognition system or the like, and high position accuracy can be obtained.

  In the case of the SI type, by adjusting exposure conditions, development conditions, etching conditions, and the like, the cross-sectional shape of the core part 111 (alignment mark) can be tapered with an appropriate slope, and the waveguide pattern forming line The line width L of 113 (alignment mark forming line) can be within the above range.

  Next, FIG. 4 is a diagram showing the relationship between the average value of the refractive index in the thickness direction and the waveguide pattern forming line 113 when the refractive index distribution in the cross section of the core 111 is W-type. More specifically, the upper part of FIG. 4 shows the waveguide pattern forming line 113 in plan view, the middle part shows the cross-sectional shape of the core part 111, and the lower part shows the average value of the refractive index in the thickness direction. Yes.

  As described above, in the W type, the refractive index distribution in the cross section continuously changes in a W shape, and the tendency is the same in the thickness direction of the core layer 11. Therefore, as shown in the lower part of FIG. 4, the distribution of the average value of the refractive index in the thickness direction is also W-shaped as a whole.

  Further, it can be seen that the position in the width direction of the waveguide pattern forming line 113 shown in the upper part of FIG. 4 corresponds to a part of the inclined portion in the W-shaped distribution of the average value of the refractive index in the thickness direction. That is, it can be seen that the positions in the width direction of both end portions P1 and P2 in the line width direction of the waveguide pattern forming line 113 are located in the inclined portions in the W-shaped distribution of the average refractive index in the thickness direction.

  The difference in the average value of the refractive index in the thickness direction at both ends P1, P2 in the line width direction of the waveguide pattern forming line 113 is the difference between R2 and R1 shown in the lower part of FIG. Therefore, in this embodiment, the difference between R2 and R1 is set within the above-described range of 0.01 to 0.05, so that the waveguide pattern forming line 113 is accurately recognized by the image recognition system or the like. And can function sufficiently as an alignment mark.

  Note that the difference between R2 and R1 is that the materials used for the core 111 and the side cladding 112 are changed, or the exposure conditions are changed to adjust the refractive indexes of the core 111 and the side cladding 112. It can be adjusted.

  Returning to FIG. 1, the width of the core portion 111 is preferably 20 to 100 μm, and more preferably 30 to 75 μm. Thereby, when the optical waveguide 1 is viewed in plan, the waveguide pattern forming line 113 constituting the outline of the waveguide pattern can be recognized more accurately. In addition, the density of the core 111 can be increased while suppressing a decrease in the transmission efficiency of the optical waveguide 1, and the transmission capacity of the optical waveguide 1 can be increased.

  The height of the core part 111, that is, the thickness of the core layer 11, is preferably 20 to 100 μm, and more preferably 30 to 75 μm. Thereby, when the optical waveguide 1 is viewed in plan, the waveguide pattern forming line 113 constituting the outline of the waveguide pattern can be recognized more accurately. Moreover, the core part 111 can be densified while suppressing a decrease in transmission efficiency of the optical waveguide 1, and the transmission capacity of the optical waveguide 1 can be increased.

  The pitch, which is the distance between the central axes of adjacent core parts 111, that is, the total width of core part 111 and side clad part 112 is preferably 50 to 500 μm, more preferably 60 to 300 μm. Thereby, when the optical waveguide 1 is viewed in plan, the pattern forming line 113 constituting the outline of the waveguide pattern can be recognized more accurately. In addition, mixing of optical signals (crosstalk) generated between the two core portions 111 can be suppressed, and the optical waveguide 1 can be densified.

  Note that the width of the side cladding portion 112 may be narrower than the width of the core portion 111 adjacent to the side cladding portion 112. Thereby, while being able to suppress crosstalk, the optical waveguide 1 can be densified. Specifically, the width of the side cladding part 112 may be 5 to 95% of the width of the adjacent core part 111, and may be 10 to 90%.

  The constituent material (main material) of the core layer 11 is, for example, (meth) acrylic resin, polycarbonate resin, polystyrene resin, cyclic ether resin such as epoxy resin or oxetane resin, polyamide resin, polyimide resin, polybenzoxazole resin, polysilane Resins, polysilazane resins, silicone resins, fluororesins, polyurethane resins, polyolefin resins, polybutadiene resins, polyisoprene resins, polychloroprene resins, polyester resins such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), polyethylene succinate resins, In addition to various resin materials such as polysulfone resin, polyether resin, cyclic olefin resin such as benzocyclobutene resin and norbornene resin, such as quartz glass and borosilicate glass Las material or the like is used. These main materials may be used alone or in combination of two or more.

  Among these main materials, at least one selected from the group consisting of (meth) acrylic resins, epoxy resins, silicone resins, polyimide resins, fluororesins, polyolefin resins and norbornene resins is preferably used. In particular, (meth) acrylic resin, epoxy resin, and norbornene resin are more preferably used. Since these resin materials have particularly high light transmittance, the optical waveguide 1 with particularly small transmission loss can be obtained by forming the core layer 11 using these resin materials.

  Note that the core portion 111 constituting the core layer 11 and the side clad portion 112 having a refractive index smaller than that of the core portion 111 are both formed using these main materials. That is, the refractive index is changed by changing the refractive index of a part of the core layer 11 or changing the composition of a part thereof by a photolithography method, a direct exposure method, a direct drawing method, a nanoimprint method, etc., which will be described later. A core part 111 having a high refractive index and a side cladding part 112 having a relatively low refractive index are formed.

  The lower clad layer 12 and the upper clad layer 13 may both be made of the same material as the constituent material of the core layer 11 described above. Is preferably made of the same material as the side cladding portion 112 having a low refractive index.

  The thickness of the lower cladding layer 12 and the upper cladding layer 13 is preferably 0.05 to 1.5 times the thickness of the core layer 11, more preferably 0.1 to 1.25 times. Specifically, the thicknesses of the lower cladding layer 12 and the upper cladding layer 13 are each preferably 1 to 150 μm, and more preferably 2 to 125 μm. Thereby, it is suppressed that the optical waveguide 1 thickens more than necessary, and the function as a clad part is ensured.

  In the present embodiment, a support film (not shown) may be provided on the lower surface of the optical waveguide 1 as necessary. Further, a cover film (not shown) may be provided on the upper surface of the optical waveguide 1 as necessary.

  As a constituent material of the support film and the cover film, for example, various resin materials such as polyolefin resins such as polyethylene terephthalate (PET), polyethylene, and polypropylene, polyimide resins, and polyamide resins are used.

  The average thickness of the support film and the cover film is preferably 5 to 500 μm, and more preferably 10 to 400 μm. Thereby, since a support film and a cover film will have moderate rigidity, while being able to support the optical waveguide 1 reliably, the optical waveguide 1 can be reliably protected from external force and an external environment.

  Next, a method for manufacturing the optical waveguide 1 according to this embodiment will be described.

  The optical waveguide 1 is manufactured by laminating the lower clad layer 12, the core layer 11, and the upper clad layer 13 in this order, and then pressure bonding or bonding them. As a method for forming the core part 111 and the side clad part 112 in the core layer 11, for example, a photolithography method, a direct exposure method, a direct drawing method, and a nanoimprint method are used.

  Among them, in the photolithography method and the direct exposure method, after irradiation with radiation such as light, development and etching are performed to form the core portion, and then the cladding portion is formed of a material different from that of the core portion. By these photolithography methods and direct exposure methods, an optical waveguide having a refractive index distribution in the cross section can be formed.

  In the direct drawing method, irradiation with radiation such as light locally irradiates radiation toward a film having a refractive index modulation ability capable of forming a refractive index difference between an exposed area and an unexposed area, and then refracts. The core part 111 and the side clad part 112 are formed by forming the rate difference. At this time, an alignment mark can be formed simultaneously with the core part 111 as needed. By this direct drawing method, an optical waveguide having a W-type or GI-type refractive index distribution in the cross section can be formed.

  Examples of the principle of refractive index modulation include monomer diffusion, photobleaching, photoisomerization, photodimerization, and the like, and one or a combination of two or more of these is used. Of these, monomer diffusion is particularly preferably employed as the principle of refractive index modulation. In monomer diffusion, light is exposed (exposed) partially to a layer composed of a material in which a photopolymerizable monomer having a refractive index different from that of the polymer is dispersed in the polymer to polymerize the photopolymerizable monomer. In addition to causing the photopolymerizable monomer to move and be unevenly distributed, the refractive index is biased in the layer. That is, a difference in refractive index occurs between the exposed area and the non-exposed area of the layer. At this time, the refractive index of the exposure region may be high or low depending on the refractive index relationship between the polymer and the photopolymerizable monomer. In this way, of the exposed region and the non-exposed region, the region on the high refractive index side becomes the core portion 1111 and the alignment mark, and the region on the low refractive index side becomes the side cladding portion 112.

  In the refractive index modulation based on such a principle, the core portion 111 having any shape can be easily formed only by selecting a region to be irradiated with light, and thus the optical waveguide 1 can be manufactured very efficiently. In addition, since the refractive index distribution formed by such a principle is formed corresponding to the concentration distribution of the photopolymerizable monomer, the refractive index distribution in the cross section of the formed core portion 111 has a smooth refractive index change. Will be accompanied. As a result, the manufactured optical waveguide 1 has a W-type or GI-type refractive index distribution, and has high transmission characteristics.

  Examples of a material that causes such monomer diffusion include a photosensitive resin composition described in Japanese Patent Application Laid-Open No. 2010-090328.

  On the other hand, in the case of refractive index modulation based on principles such as photobleaching, photoisomerization, and photodimerization, the amount of change in refractive index can be adjusted according to the amount of irradiated light (radiation amount). In photobleaching, the molecular structure in the material is cleaved by light irradiation, and the leaving group is detached from the main chain. Thereby, the refractive index of the material is changed, and the core portion 111 and the alignment mark are formed. Further, in photoisomerization and photodimerization, photoirradiation of a material causes photoisomerization or photodimerization, and the refractive index of the material changes. Thereby, the core part 111 and the alignment mark are formed.

  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. Examples of the material that causes photodimerization include a photosensitive resin composition described in JP2011-105791A.

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

  Alternatively, the refractive index difference may be formed by diffusing the refractive index adjusting agent in the polymer and continuously changing the concentration of the refractive index adjusting agent. Examples of a method for supplying the refractive index adjusting agent into the polymer include methods such as coating, spraying, adhesion, dipping, and deposition. When supplying the refractive index adjusting agent by such a supply method, an arbitrary refractive index distribution can be formed by adjusting the supply amount for each region. In addition, as a refractive index regulator, what was described in Unexamined-Japanese-Patent No. 2006-276735 is mentioned, for example.

  As an exposure apparatus, an exposure apparatus that uses a photomask corresponding to the optical waveguide pattern to be formed may be used, but the area to be irradiated with light is finely controlled so that only an area to be exposed without using a photomask is used. An apparatus (maskless exposure apparatus) that selectively irradiates light is preferably used. According to this maskless exposure apparatus, it is possible to perform the exposure process efficiently with high spatial resolution. In addition, since a photomask is not required, the cost of the exposure process can be reduced, and switching to a different optical waveguide pattern can be performed quickly, which is suitable for high-mix low-volume production.

  As mentioned above, according to the optical waveguide 1 which concerns on this embodiment, the following effects are show | played.

  In this embodiment, the average value of the refractive index in the thickness direction of the core layer 11 is changed in the line width direction so as to include the waveguide pattern forming line 113 (when the alignment mark is formed, the alignment mark forming line is also included). The same shall apply hereinafter). In addition, the difference in the average refractive index in the thickness direction at both ends in the line width direction of the waveguide pattern forming line 113 was defined as a range in which the waveguide pattern forming line 113 functions as an alignment mark.

As a result, the waveguide pattern forming line 113 can be accurately recognized by the image recognition system and can function as an alignment mark. Therefore, processing can be performed at an accurate position with reference to the waveguide pattern forming line 113.
[Method of manufacturing optical waveguide module]
Next, a method for manufacturing the optical waveguide module according to this embodiment will be described.

  In the method for manufacturing an optical waveguide module according to this embodiment, the above-described optical waveguide 1 is used. The optical waveguide module manufacturing method according to the present embodiment is processed based on the position of the above-described waveguide pattern forming line 113 (the alignment mark forming line may be used when the above-described alignment mark is formed; the same applies hereinafter). It has a processing step for determining the position and processing the optical waveguide 1.

  FIG. 5 is a diagram illustrating an example of processing of the optical waveguide 1 according to the present embodiment.

  As shown in FIG. 5, as a processing step for processing the optical waveguide 1, for example, a mirror processing step in which a part of the core part 111 is recessed to form a mirror, and a guide hole in a part of the side cladding part 112. And a guide hole processing step of forming Hereinafter, these processing steps will be described in detail.

  In the mirror processing step, the light conversion mirror 17 is formed on a part of the core portion 111. The mirror 17 is formed using a part of the inner surface of the recess 170 obtained by recessing a part of the core part 111. By this mirror 17, the optical path of the signal light propagating through the core portion 111 is converted, and the signal light can be taken out of the optical waveguide 1. Since the reflection angle of the signal light varies greatly depending on the position and angle of the mirror 17, the formation position of the recess 170 is extremely important from the viewpoint of optical coupling efficiency between the optical waveguide 1 and other optical components.

  For the formation of the mirror 17, for example, a cutting / grinding machine such as a dicer, a molding machine that presses a molding die, a laser beam machine, an electron beam machine, or the like is used. Each of these processing machines includes a stage on which a workpiece is placed and a processing tool, and performs processing of an arbitrary shape by processing the workpiece while relatively moving at least one of them. In addition, these processing machines are provided with the above-described image recognition system, and the processing is performed by recognizing the waveguide pattern forming line 113 of the optical waveguide 1 by the imaging device (for example, CCD, CMOS, etc.) of the image recognition system. The coordinate system inside the machine is made to correspond to the coordinate system of the optical waveguide 1. Such correspondence of the coordinate system enables accurate processing to be performed at an arbitrary position of the optical waveguide 1 with the waveguide pattern forming line 113 as a reference point.

  Specifically, first, the image recognition system of these processing machines is caused to recognize the waveguide pattern forming line 113 of the optical waveguide 1. The recognition of the waveguide pattern forming line 113 is performed by the imaging device of the stage and the image recognition system so that the pattern stored in the image recognition system in advance matches the image of the waveguide pattern forming line 113 captured by the imaging device. These are performed by a method of relatively moving at least one of them (pattern matching method), a method of detecting the contrast of the edge of the waveguide pattern forming line 113 (edge detection method), or the like.

  Next, the recess 170 is processed in the optical waveguide 1 based on the coordinate system inside the processing machine and the coordinates of the processing position by optical design. Thereby, processing is performed at the designed position, and the mirror 17 is formed.

  Next, a guide hole 18 is formed in the optical waveguide 1 in the guide hole processing step. For the formation of the guide hole 18, a machine tool such as a micro drill, a molding machine, a laser beam machine, an electron beam machine, or the like is used.

  To form the guide hole 18, as in the case of forming the mirror 17, first, the waveguide pattern forming line 113 of the optical waveguide 1 is recognized by the image recognition system of the processing machine, and the coordinate system inside the processing machine is guided to Corresponding to the coordinate system of the waveguide 1. Next, a guide hole 18 is formed in the optical waveguide 1 on the basis of the coordinate system inside the processing machine and the arrangement of the guide pins provided in other optical components and the arrangement of the light receiving and emitting portions.

  The guide hole 18 can match the optical axis of the core portion of another optical component (for example, an optical fiber) optically connected to the optical waveguide 1 and the optical axis of the core portion 111 of the optical waveguide 1.

  Specifically, as shown in FIG. 5, the guide pin 911 of the optical connector 91 attached to the end of the optical fiber 9 is inserted into the formed guide hole 18. Thereby, the optical axis of the core part 111 of the optical waveguide 1 and the optical axis of the core part of the optical fiber can be matched and optically connected.

  The waveguide pattern forming line 113 is not only used as a reference for processing, but also with respect to the optical waveguide 1, various optical components such as a lens, a diffraction grating, a filter, and a polarizer, a light emitting element (VCSEL), a light receiving element. It is also used as a reference for mounting various optical elements such as an element (PD), various electric elements such as LSI and IC, various electric circuit boards and the like. When mounting these components and elements, various bonders such as a die bonder and a flip chip bonder and various mounters such as a chip mounter can be used as necessary. Even in these apparatuses, the image recognition system may recognize the waveguide pattern forming line 113 so that the coordinate system inside the apparatus corresponds to the coordinate system of the optical waveguide 1.

  As mentioned above, according to the manufacturing method of the optical waveguide module concerning this embodiment, the following effects are produced.

That is, a waveguide that can be accurately recognized by the image recognition system and functions as an alignment mark by determining a processing position based on the position of the waveguide pattern forming line 113 and processing the optical waveguide 1. Since various types of processing can be performed with reference to the pattern forming line 113, processing can be performed at an accurate position. As a result, an optical waveguide module having high optical coupling efficiency can be manufactured.
[Electronics]
Next, the electronic apparatus according to the present embodiment will be described.

  The electronic device according to the present embodiment includes the optical waveguide 1 described above. Specifically, electronic devices according to the present embodiment include electronic devices such as mobile phones, game machines, router devices, WDM devices, personal computers, televisions, home servers, and the like. In these electronic devices, since the large-capacity data needs to be transmitted at high speed between an arithmetic device such as an LSI and a storage device such as a RAM, the above-described optical waveguide 1 is preferably used. .

  The electronic device according to this embodiment has the following effects.

  As described above, since the optical waveguide 1 can be subjected to various types of processing with high positional accuracy, it is possible to increase the optical coupling efficiency when connecting to other optical components. Therefore, according to the electronic device according to the present embodiment, problems such as noise and signal degradation peculiar to the electrical wiring are solved, and a highly reliable electronic device that can perform high-quality optical communication is obtained. Further, in the optical waveguide 1, the amount of heat generation is greatly reduced as compared with the conventional electric wiring. Therefore, the power required for cooling can be reduced, and the power consumption of the entire electronic device can be reduced.

  It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements, etc. within a scope that can achieve the object of the present invention are included in the present invention.

Next, examples of the present invention will be described, but the present invention is not limited to these examples.
[Manufacture of optical waveguides]
<Example 1>
As Example 1, an optical waveguide having an SI refractive index distribution in the cross section of the core portion was manufactured by the following procedure.

(1) Production of Cladding Layer Forming Resin Composition Daicel Chemical Industries Co., Ltd. alicyclic epoxy resin, 20 g of Celoxide 2081, ADEKA Co., Ltd. cationic polymerization initiator, Adekaoptomer SP-170 0 .6 g and 80 g of methyl isobutyl ketone were mixed with stirring to prepare a solution.

  Next, 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 epoxy polymer, phenoxy resin manufactured by Nippon Steel Chemical Co., Ltd., 20 g of YP-50S, and 5 g of Celoxide 2021P manufactured by Daicel Chemical Industries, Ltd. as a photopolymerizable monomer, Then, 0.2 g of Adeka optomer SP-170 manufactured by ADEKA Co., Ltd. was added as a polymerization initiator 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 Cladding Layer After the clad layer forming resin composition prepared in (1) was uniformly applied onto a polyimide film having a thickness of 25 μm with a doctor blade, it was put into 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 clad layer having a thickness of 20 μm was obtained. The cumulative amount of ultraviolet light was 500 mJ / cm ² .

(4) Production of core layer On the clad layer produced in (3), the photosensitive resin composition prepared in (2) was uniformly applied with a doctor blade, and then placed in a dryer at 40 ° C for 5 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 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. Thereafter, the core pattern was developed using a developer (propylene glycol monomethyl ether acetate / cyclohexanone = 7/3, mass ratio).

(5) Production of optical waveguide The clad layer produced in (3) was laminated on the core layer produced in (4) to obtain an optical waveguide.

(6) Measurement of refractive index About the optical waveguide obtained by (5), the refractive index of the thickness direction in the both ends of the line | wire width direction of a waveguide pattern formation line was implemented. The measurement was performed at 10 points at equal intervals in the thickness direction using a laser interference microscope. Subsequently, the difference of the average value of the refractive index obtained by measurement was calculated | required. As a result, the difference in the average refractive index in the thickness direction at both ends in the line width direction of the waveguide pattern forming line was 0.05. The line width of the waveguide pattern forming line was 6 μm.

(7) Fabrication of mirror Next, the optical waveguide obtained in (5) was set in a laser processing machine, and a waveguide pattern forming line was recognized by an image recognition system. Next, based on the position of the waveguide pattern forming line, a recess was processed at a position designed according to the position of the core by laser processing. This produced a mirror. The mirror formation positions were as shown in FIG. As described above, an optical waveguide having a length of 10 cm was obtained.
<Example 2>
As Example 2, an optical waveguide having a W-shaped refractive index distribution in the cross section of the core portion was manufactured by the following procedure.

(1) Synthesis of a polyolefin-based resin having a leaving group In a glove box filled with dry nitrogen, both moisture and oxygen concentrations are controlled to 1 ppm or less, and 7.2 g (40.1 mmol) of hexylnorbornene (HxNB) Then, 12.9 g (40.1 mmol) of diphenylmethylnorbornenemethoxysilane 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 for 1 hour at room temperature, 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, 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 polymer # 1 was Mw = 100,000 and Mn = 40,000 as a result of 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 a result of identification by NMR measurement.

(2) Production of composition for forming core layer 10 g of the purified polymer # 1 was weighed into a 100 mL glass container, and 40 g of mesitylene, 0.01 g of an antioxidant Irganox 1076 (manufactured by Ciba Geigy), cyclohexyloxetane monomer ( Toagosei CHOX, CAS # 48333-3-25-9, molecular weight 186, boiling point 125 ° C./1.33 kPa) 2 g, polymerization initiator (photoacid generator) “Rhodosil Photoinitiator 2074” (manufactured by Rhodia, CAS # 178233-72 2) (0.0125 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 core layer forming composition.

(3) Production of Cladding Layer A norbornene-based resin composition containing a cyclic olefin-based resin (20 wt% 2-heptanone solution of A vatel 2590 manufactured by Promeras, 10 g) was added to 2-undecylmethylimidazole (manufactured by Shikoku Chemical Industries, Ltd. , Product number C11Z) (0.06 g) was added and mixed to obtain an optical waveguide coating solution. The optical waveguide coating solution was uniformly applied onto the two polyimide films with a doctor blade, and then dried in a dryer at 45 ° C. for 15 minutes. After completely removing the solvent, the coating film was cured by heating in a dryer at 160 ° C. for 2 hours to form two optical waveguide forming films (cladding layers).

(4) Preparation of core layer The composition for core layer formation was uniformly apply | coated with the doctor blade on the mold release process PET film, Then, it injected | threw-in to the dryer of 40 degreeC for 5 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 cumulative amount of ultraviolet light was 1300 mJ / cm ² .

  Next, the photomask was removed and placed in an oven at 150 ° C. for 30 minutes. When taken out from the oven, it was confirmed that a clear waveguide pattern having a rectangular cross section appeared on the coating. The thickness of the obtained core layer was 50 μm.

(5) Production of optical waveguide The clad layer was laminated on both surfaces of the core layer with a laminator to obtain a laminate. The obtained laminate was heat-treated at 160 ° C. for 2 hours to obtain an optical waveguide.

(6) Measurement of refractive index About the optical waveguide obtained by (5), the refractive index of the thickness direction in the both ends of the line | wire width direction of a waveguide pattern formation line was implemented. The measurement was performed at 10 points at equal intervals in the thickness direction using a laser interference microscope as in Example 1. Subsequently, the difference of the average value of the refractive index obtained by measurement was calculated | required. As a result, the difference in the average refractive index in the thickness direction at both ends in the line width direction of the waveguide pattern forming line was 0.02. The line width of the waveguide pattern forming line was 3 μm.

(7) Production of Mirror Next, a mirror was produced in the same manner as in Example 1.
<Comparative Example 1>
Using the same material as in Example 1, an optical waveguide was obtained in the same manner as in Example 1 except for the exposure conditions. Further, in the same manner as in Example 1, the refractive index in the thickness direction was measured at both ends of the waveguide pattern forming line in the line width direction. As a result, the difference in the average refractive index in the thickness direction at both ends in the line width direction of the waveguide pattern forming line was 0.005. The line width of the waveguide pattern forming line was 8 μm.
[Evaluation of optical waveguide]
For the optical waveguides obtained in Examples 1 and 2 and Comparative Example 1, the maximum deviation between the designed position of the mirror formed corresponding to each core part and the actual position by processing was measured. And the maximum deviation | shift amount in eight core parts was averaged, and this was made into the parameter | index of processing accuracy.

  When the above-mentioned index was compared for each optical waveguide, it was found that the average maximum deviation amount of Examples 1 and 2 was smaller than the average maximum deviation amount of Comparative Example 1. From this result, it was confirmed that the optical waveguide of the present invention has high stability and reliability as a reference point of the waveguide pattern forming line. Therefore, according to the optical waveguide of the present invention, it was confirmed that the waveguide pattern forming line functions as an alignment mark and can be processed with high positional accuracy.

DESCRIPTION OF SYMBOLS 1 ... Optical waveguide 11 ... Core layer 12 ... Lower clad layer 13 ... Upper clad layer 111 ... Core part 112 ... Side clad part (clad part)
113 ... Waveguide pattern formation line (formation line)

Claims (8)

An optical waveguide having a core layer having a long core portion,
Comprising a forming line formed by changing the average value of the refractive index in the thickness direction of the core layer in the line width direction;
An optical waveguide in which the difference between the average values at both ends in the line width direction of the forming line is a range in which the forming line functions as an alignment mark.   The optical waveguide according to claim 1, wherein the difference between the average values is 0.01 to 0.05.   The optical waveguide according to claim 1, wherein the formed line has a line width of 1 to 7 μm.   4. The optical waveguide according to claim 1, wherein a width of the core portion is 20 to 100 μm, and a height of the core portion is 20 to 100 μm.   The optical waveguide according to any one of claims 1 to 4, wherein a pitch, which is a distance between central axes of adjacent core portions, is 50 to 500 µm. An optical waveguide comprising a core layer having an elongated core portion and a cladding portion adjacent to a side surface of the core portion,
An optical waveguide in which at least one of an inclined surface and a curved surface functioning as a forming line as an alignment mark is provided at an interface between the core portion and the cladding portion. A method of manufacturing an optical waveguide module using the optical waveguide according to any one of claims 1 to 6,
A method of manufacturing an optical waveguide module, comprising a processing step of determining a processing position on the basis of the position of the forming line and processing the optical waveguide.   An electronic device comprising the optical waveguide according to claim 1.