JP2008059001A - Method for manufacturing optical waveguide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical waveguide that is inexpensive with high use efficiency of a core material, and to provide a method for manufacturing the optical waveguide. <P>SOLUTION: The method for manufacturing an optical waveguide comprises: a step of forming a first clad (2) by applying a resin on a substrate (20) and curing the resin; a step of holding a core material (1') between a recessed mold (10) having a recess identical to a shape of the core and the first clad on the substrate; a step of curing the core material thus applied, thereby forming a core pattern (1) having a shape identical to that of the recess on the first clad; and a step of peeling the recessed mold (10) from the core pattern and the first clad. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method of manufacturing an optical waveguide used for optical interconnection or the like.

  In recent years, the advance of optical communication technology has demonstrated the superiority of optical communication compared to telecommunication. In addition, with the increase in the speed of signals from LSIs and the like, development of techniques for replacing electrical signals with optical signals is underway. As an optical signal transmission medium, a polymer optical waveguide that has been developed in recent years is expected.

  The polymer optical waveguide can be formed in a large area, and is applied to an optical interconnection on the order of 1 cm to 1 m. In the polymer optical waveguide, an optical component can be mounted on the surface of the optical path conversion mirror by forming an optical path conversion mirror at the end of the waveguide.

(Waveguide manufacturing method)
As a method for producing a polymer optical waveguide, a method using dry etching as shown in FIG. 44 and a method using pattern exposure and development as shown in FIG. 45 are generally used.

  Specifically, in the method using dry etching, as shown in FIG. 44A, a first clad 2 and a core 1 are sequentially formed on a substrate 50. As shown in FIG. 44B, a silicon-containing resist 51 is partially formed on the core 1. As shown in FIG. 44C, the silicon-containing resist 51 and the core 1 are irradiated with reactive ions 52, and the core 1 exposed from the silicon-containing resist 51 is etched. As shown in FIG. 44 (d), the silicon-containing resist 51 is removed, and the convex core 1 is formed. As shown in FIG. 44 (e), the second cladding 3 is formed on the convex core 1 and the first cladding 2.

  On the other hand, in the method using pattern exposure and development, as shown in FIGS. 45A and 45B, the first clad 2 and the core material 1 ′ are sequentially formed on the substrate 50. As shown in FIG. 45C, the core material 1 'is irradiated with ultraviolet rays 53 through a photomask 35 to selectively cure the core material 1'. As shown in FIG. 45 (d), the core material 1 'that is not cured is removed by development to form a convex core 1. As shown in FIG. 45 (e), the second cladding 3 is formed on the convex core 1 and the first cladding 2.

  In addition, as shown in FIG. 46, the optical path conversion mirror is generally formed by machining with a dicing saw. In machining by a dicing saw, as shown in FIG. 46 (a), as shown in FIG. 44 (e) or 45 (e), the core 1 has claddings 2 and 3 embedded therein. A substrate 50 is prepared. As shown in FIG. 46 (b), both ends of the core 1 are cut obliquely together with the clads 2 and 3 by a dicing blade 54. As shown in FIG. 46 (c), both end portions of the core 1 are formed on the total reflection mirror 55. At this time, an optical path is formed so that the signal light 8 incident on one end of the core 1 is emitted from the other end through the inside of the core 1.

  However, the manufacture of the waveguide shown in FIGS. 44 and 45 and the processing of the optical path conversion mirror shown in FIG. 46 are performed separately, which complicates the manufacturing process and increases the cost.

  Therefore, a method using a mold is considered as a method for simultaneously producing a waveguide and a mirror (for example, see pages 8 to 9 and FIGS. 2 to 3 of Japanese Patent Application Laid-Open No. 2001-154049). reference.). In the method using a mold, a core is applied to the entire surface of a substrate having a recess, and the core other than the recess is removed. Next, a first cladding is formed on the entire surface of the substrate so as to cover the core, and the core and the first cladding are transferred to another substrate. Thereafter, a second cladding is formed on the core and the first cladding.

  However, this method removes the cores other than the recesses among the cores applied to the entire surface of the substrate, so that the use efficiency of the core material is low and the cost is increased.

  On the other hand, there is a method in which the use efficiency of the core material is good (for example, see page 7 and FIGS. 1 to 5 of Japanese Patent Application Laid-Open No. 10-90544). In this method, a concave member formed by forming a light shielding film in addition to the depression (concave portion) is used in the concave member having light transmittance. For this reason, only the core pattern can be cured by light irradiation through the concave mold. However, since the resin of the concave member is easily deformed by heat, the core pattern is easily deformed.

  Similar technologies include “WJOh, MSKim, HHByum, JWKim, KSHan, JHOh, MSKwon, and SYShin,“ Fabrication of Multimode Polymer Optical Waveguides by Using UV Curable Resins and Transfer Molding Process ”. , Seventh Optoelectronics and Communications Conference (OECC 2002) Technical Digest, pp.534-535, July 2002. ”. This technology also uses light irradiation through a concave mold as described in “the PDMS mold is transparent to UV light” (page 534, right column, lines 11-12), so that the resin of the concave mold is deformed by heat. It is considered easy.

(Optical component mounting)
In the optical waveguide, a mirror that changes the optical path is formed on the core, and an optical component that is a light receiving element or a light emitting element is mounted on the surface of the optical waveguide on the optical axis of the mirror.

  Usually, a plane mirror is used as an optical path conversion mirror.

  For connection from the light emitting element to the core, normally, divergent light from the light emitting element is converted into convergent light by a convex lens and condensed on an optical path conversion mirror. For connection from the core to the light receiving element, in order to improve the connection efficiency and the positional deviation margin of the light receiving element, the light emitted from the optical path conversion mirror at the end of the core is converged by a convex lens (lens) and then incident on the PD. The method is used (for example, see Japanese Patent Application Laid-Open No. 2001-185752).

  On the other hand, as shown in FIG. 47, both the light-emitting element 40 and the light-receiving element 41 are placed close to the optical path conversion mirrors 4 and 6, and the light-emitting diameter <core diameter <light-receiving diameter is reached. There is also a method of omitting the convex lens.

(Waveguide mounting)
Conventionally, in an optical waveguide, as shown in FIG. 48, a straight waveguide, a curved waveguide, and an oblique mirror at the end of the waveguide are used (for example, Journal of the Institute of Electronics, Information and Communication Engineers, Vol. 84, No. 9, pp. 656-662, September 2001 (see p.661, Fig. 8)). Specifically, a linear waveguide is basically used, and a curved waveguide is used when changing the position and orientation of the linear waveguide. An oblique mirror is used for connecting each waveguide to a surface light emitting element or a light receiving element (also referred to as an external element).

(Lamination with another substrate)
Next, the case where the optical waveguide 7 is formed in a film shape and bonded to another substrate will be described.

  As shown in FIGS. 49A to 49F, a film of the optical waveguide 7 is manufactured. That is, as shown in FIG. 49A, the first clad 2 is formed on the substrate 20, and as shown in FIG. 49B, the alignment mark (alignment mark) is partially formed on the first clad 2. ) 70 is formed.

  Next, as shown in FIG. 49C, the core 1 having a predetermined pattern is formed on the first clad 2 so as not to overlap the alignment mark 70. In FIG. 49 (c), the core 1 and the alignment mark 70 are depicted side by side, but in reality, the core 1 and the alignment mark 70 are in a position shifted from each other in the direction perpendicular to the paper surface. In addition, as shown in FIG. 49D, the second cladding 3 is formed on the core 1 and the first cladding 2. Thereby, the optical waveguide 7 is formed on the substrate 20.

  Thereafter, as shown in FIG. 49E, inclined total reflection mirror surfaces 55 are formed at both ends of the core 1. When the substrate 20 is peeled from the optical waveguide, a film-like optical waveguide 7 is manufactured as shown in FIG.

  Next, as shown in FIG. 49G, the alignment mark 70 of the optical waveguide 7 is aligned with the alignment mark 61 of another substrate (eg, electric wiring substrate) 60, and the optical waveguide 7 and the separate substrate 60 are aligned. Are bonded with an adhesive 62. Thereby, the bonding structure of the optical waveguide 7 and the separate substrate 60 is completed.

  As described above, the conventional method for manufacturing an optical waveguide has a problem that the use efficiency of the core material is low and the cost is increased. There is also a problem that the core pattern is easily deformed.

  An object of the present invention is to provide an inexpensive optical waveguide manufacturing method in which the core material is used efficiently and the core is not easily deformed.

  A first aspect of the present invention is a method of manufacturing an optical waveguide composed of a core and a clad, the step of forming a first clad by applying and curing a resin on a substrate, and the core pattern shape. A step of sandwiching a core material between a concave mold having a recess and a backing material on the back and a first clad on the substrate; and a core pattern corresponding to the recess is cured by curing the sandwiched core material. An optical waveguide manufacturing method comprising: a step of forming on one clad; and a step of peeling a concave mold from the core pattern and the first clad.

  As described above, since the core material is put in the depression, the use efficiency of the core material is good, and since the light is not irradiated from the concave mold side, an inexpensive optical waveguide manufacturing method in which the core is not easily deformed is provided. Can do.

  A second aspect of the present invention is an optical waveguide structure in which a core is sandwiched between clads, and is provided with a concave mirror that is provided at one end of the core and converts the signal light incident from the vertical direction into the core. The focal point of the concave mirror is an optical waveguide that substantially matches the distance from the central point of the concave mirror to the light emitting point of the light emitting element that generates the signal light.

  As described above, since the concave mirror is used, the connection efficiency of the optical path conversion mirror is good, the element displacement margin can be increased, the structure is simple, and an inexpensive optical waveguide can be provided.

  A third aspect of the present invention is an optical waveguide in which a plurality of cores are sandwiched between clads, and the first core of the plurality of cores has at least two extending directions and is in-plane with each other. A plurality of linear waveguides connected by mirrors, and the other core of the plurality of cores is an extension direction of any one of the linear waveguides included in the first core Is an optical waveguide provided with a straight waveguide having an extension direction substantially coinciding with.

  As described above, since the area required for the direction change can be reduced due to the use of the in-plane mirror, and the plurality of cores are standardized to include the linear waveguide having one of the two extending directions, the laser processing The number of setting times can be reduced. Therefore, it is possible to provide an optical waveguide suitable for manufacturing a core connecting a large number of arbitrary points.

  A fourth aspect of the present invention is an optical waveguide structure that can be bonded to another substrate, and includes a first clad, a core partially formed on the first clad, and a part on the first clad. A base member having a top portion at a position equal to or higher than the height of the core, an alignment mark formed on the top portion of the base member, and the first clad so as to cover the base member and the core. And an optical waveguide provided with the second clad formed on the substrate.

  As described above, since the base member and the alignment mark are provided, it is possible to improve the distance and alignment accuracy between the optical waveguide and another substrate, and to provide an optical waveguide suitable for bonding to another substrate. it can.

  Further, the following 43 inventions are described in the claims at the beginning of the application of the basic application (Japanese Patent Application No. 2004-537571) of the divisional application.

  1st invention is a manufacturing method of the optical waveguide which consists of a core and a clad, Comprising: The process of apply | coating and hardening resin on a board | substrate (20), and forming the 1st clad (2), The said core pattern shape A step of sandwiching a core material (1 ′) between a concave mold (10) having a depression and a first clad on the substrate, and a core pattern (1) corresponding to the depression by curing the sandwiched core material Is formed on the first cladding, and the concave mold (10) is peeled off from the core pattern and the first cladding.

  According to a second aspect of the present invention, in the method of manufacturing an optical waveguide corresponding to the first aspect of the invention, the step of curing the sandwiched core material (1 ′) includes passing ultraviolet light into the core material through the substrate and the first cladding. It is the manufacturing method of the optical waveguide including the ultraviolet curing process to irradiate.

  A third invention is a method for manufacturing an optical waveguide corresponding to the first invention, wherein the step of sandwiching the core material (1 ') is a method for manufacturing an optical waveguide using a press roll (11).

  According to a fourth aspect of the present invention, there is provided an optical waveguide manufacturing method corresponding to the third aspect of the present invention, wherein the angle formed by the substrate movement direction of the press roll and the main straight line portion of the concave recess is approximately 45 ° or less. It is a manufacturing method of a waveguide.

  According to a fifth aspect of the present invention, in the optical waveguide manufacturing method corresponding to the first aspect, a resin is applied and cured so as to cover the core pattern (1) and the first cladding (2). And a step of forming an optical waveguide.

  According to a sixth aspect of the present invention, in the method of manufacturing an optical waveguide corresponding to the first aspect, after the step of peeling the concave mold (10) is completed, the step of removing the thin remaining core on the first cladding surface is further performed. A manufacturing method of an optical waveguide provided.

  According to a seventh aspect of the present invention, in the optical waveguide manufacturing method corresponding to the sixth aspect of the invention, the step of removing the thin remaining core is an optical waveguide manufacturing method using oxygen plasma treatment.

  According to an eighth aspect of the present invention, there is provided an optical waveguide manufacturing method corresponding to the first aspect, wherein the concave mold (10) has an inclined mirror equivalent surface having an end of the depression of approximately 45 °, and the core pattern. (1) is a method of manufacturing an optical waveguide having an end portion to which the oblique mirror equivalent surface is transferred.

  According to a ninth invention, in the optical waveguide manufacturing method corresponding to the eighth invention, a reflective film is formed in advance on the mirror equivalent surface of the concave mold (10) before the step of sandwiching the core material (1 ′). The step of forming a film and the step of peeling off the concave mold (10) is a method of manufacturing an optical waveguide, including a step of transferring the reflective film to an end of a core pattern.

  According to a tenth aspect of the present invention, in the method of manufacturing an optical waveguide corresponding to the first aspect, the recess in the concave mold (10) includes two straight portions formed so that one ends thereof are connected to each other at right angles, and these straight lines. A method of manufacturing an optical waveguide comprising: an in-plane mirror equivalent surface for optically connecting the portions; and the core pattern (1) is formed by transferring the linear portions and the in-plane mirror equivalent surface. It is.

  An eleventh aspect of the invention is the method for manufacturing an optical waveguide according to the first aspect, wherein the concave mold (10) has a concave curved end portion.

  A twelfth aspect of the invention is a method of manufacturing an optical waveguide corresponding to the first aspect of the invention, wherein the depression in the concave mold (10) is formed deeper than the depth of the core pattern shape separately from the core pattern shape. A manufacturing method of an optical waveguide having a shape.

  According to a thirteenth aspect of the present invention, in the method for manufacturing an optical waveguide corresponding to the first aspect of the invention, the recess in the concave mold (10) is formed to a depth equal to or greater than the depth of the core pattern shape separately from the core pattern shape. It is a manufacturing method of the optical waveguide which has the base member shape made.

  A fourteenth invention is a method for manufacturing an optical waveguide corresponding to the first invention, wherein the concave mold (10) has at least a surface material of silicone resin or fluororesin.

  According to a fifteenth aspect of the present invention, in the method of manufacturing an optical waveguide corresponding to the first aspect, the core material (1 ′) and the core material (1 ′) are previously placed in the concave mold (10) before the step of sandwiching the core material (1 ′). And a step of performing a surface treatment for increasing the affinity of the optical waveguide.

  A sixteenth aspect of the invention is a method for manufacturing an optical waveguide corresponding to the fifteenth aspect of the invention, wherein the surface treatment is an oxygen plasma treatment.

  According to a seventeenth aspect of the present invention, in the optical waveguide manufacturing method corresponding to the fifteenth aspect of the invention, the surface treatment is a treatment for setting the contact angle of the core material (1 ′) to the concave mold (10) to 45 ° or less. It is a manufacturing method of an optical waveguide.

  According to an eighteenth aspect of the invention, in the method of manufacturing an optical waveguide corresponding to the first aspect of the invention, the step of forming the convex mold (30) by forming the core pattern-shaped convex section (32) on the substrate (31). And a step of applying and curing a resin to the convex mold and peeling the convex mold from the resin to produce a concave mold (10).

  According to a nineteenth aspect of the present invention, there is provided an optical waveguide manufacturing method corresponding to the eighteenth aspect of the present invention, wherein the convex portion of the convex mold (30) includes two linear portions formed so that one ends thereof are connected at right angles to each other. And an optical waveguide manufacturing method including an in-plane mirror equivalent surface for optically connecting these linear portions.

  A twentieth aspect of the invention is a method of manufacturing an optical waveguide corresponding to the nineteenth aspect of the invention, wherein the surface corresponding to the convex in-plane mirror is formed by laser processing.

  A twenty-first aspect of the invention is a method of manufacturing an optical waveguide according to the nineteenth aspect of the invention, wherein the convex portion has an end portion corresponding to an oblique mirror.

  According to a twenty-second aspect of the invention, there is provided an optical waveguide manufacturing method according to the twenty-first aspect of the invention, wherein the inclined mirror-corresponding surface of the convex portion is formed as an inclined convex curved surface.

  A twenty-third aspect of the invention is a method of manufacturing an optical waveguide corresponding to the twenty-first aspect of the invention, wherein the surface corresponding to the convex oblique mirror is formed by laser processing.

  According to a twenty-fourth aspect of the invention, in the optical waveguide manufacturing method corresponding to the twenty-second aspect of the invention, the step of producing the convex mold (30) is performed by photolithography from a resist pattern having a core pattern shape on the substrate (31). A step of forming a convex portion, and a laser beam having a substantially circular shadow is obliquely applied to the end portion of the convex portion, and the end portion is partially evaporated, whereby the slope-shaped convex portion is formed. And a step of forming a curved surface.

  According to a twenty-fifth aspect of the invention, in the optical waveguide manufacturing method corresponding to the twenty-second aspect of the invention, the step of producing the convex mold (30) is performed by photolithography from a resist pattern having a core pattern shape on the substrate (31). Forming the convex portion, and irradiating the end portion of the convex portion with laser light a plurality of times from different directions and partially evaporating the end portion, thereby forming the inclined convex curved surface. And an optical waveguide manufacturing method.

  According to a twenty-sixth aspect of the invention, in the method of manufacturing an optical waveguide corresponding to the twenty-second aspect of the invention, the step of producing the convex mold (30) is performed by photolithography from a resist pattern having a core pattern shape on the substrate (31). A step of forming a convex portion, a step of obliquely irradiating the end portion of the convex portion with laser light and partially evaporating the end portion, thereby forming the end portion into a slope shape, and the laser And a step of forming the sloped convex curved surface by increasing the temperature and causing the resist to flow after light irradiation.

  A twenty-seventh aspect of the invention is an optical waveguide in which a plurality of cores (A, B) are sandwiched between clads (2, 3), and among the plurality of cores, the first core (A) includes at least two A plurality of linear waveguides (45) having extension directions (X, Y) and connected to each other by in-plane mirrors (5) are provided. Among the plurality of cores, the other core (B) 1 is an optical waveguide including a linear waveguide (45) having an extension direction (X) substantially coincident with the extension direction (X) of any one of the linear waveguides included in one core.

  In a twenty-eighth aspect of the present invention, in the optical waveguide corresponding to the twenty-seventh aspect, the width (b) of the in-plane mirror (5) projected on the plane perpendicular to the linear waveguide (45i) on the light incident side is The optical waveguide is larger than the width (a) of the core of the linear waveguide (45i) on the incident side.

  In a twenty-ninth aspect of the present invention, in the optical waveguide corresponding to the twenty-eighth aspect, the width (c) of the in-plane mirror (5) projected on the plane perpendicular to the linear waveguide (45o) on the light emitting side is the light This is an optical waveguide that is equal to or smaller than the width (d) of the core of the output side straight waveguide (45o).

  A thirtieth aspect of the invention is an optical waveguide corresponding to the twenty-seventh aspect of the invention, wherein both ends of each core (A, B) are provided with oblique mirrors (4) for connection to external elements.

  According to a thirty-first aspect, in the optical waveguide corresponding to the thirtieth aspect, the width (f) of the oblique mirror (4) is larger than the width (e) of the core of the linear waveguide (45) in contact with the oblique mirror. It is a large optical waveguide.

  A thirty-second invention is an optical waveguide corresponding to the thirty-first invention, wherein the oblique mirror (4) having the width (f) is formed on the light emitting side.

  In a thirty-third aspect of the invention, in the optical waveguide in which the core (1) is sandwiched between the clads (2, 3), the signal light (8) that is provided at one end of the core and is incident from the vertical direction enters the core (1). A concave mirror (4, 6) for changing the optical path is provided, and the focal length (9) of the concave mirror substantially coincides with the distance from the central point of the concave mirror to the light emitting point of the light emitting element (40) that generates the signal light. It is an optical waveguide.

  In a thirty-fourth aspect of the present invention, an optical waveguide in which a core (1) is sandwiched between clads (2, 3) is provided at one end of the core and optically converts light (8) passing through the core in the vertical direction. A concave mirror (4, 6) for emitting light, and the focal length (9) of the concave mirror is from the center point of the concave mirror to the light receiving element (41) installed on the optical axis in the vertical direction. The optical waveguide is in the range of 1/2 to 1 times the distance.

  In a thirty-fifth aspect of the present invention, in an optical waveguide that can be bonded to another substrate (60), a first clad (2), a core (1) partially formed on the first clad, and the first clad And a spacer (71) partially formed thereon and having a top at a position higher than the core.

  A thirty-sixth invention is the optical waveguide corresponding to the thirty-fifth invention, wherein the spacer (71) is formed of the same material as the core (1).

  In a thirty-seventh aspect of the present invention, in the optical waveguide corresponding to the thirty-fifth aspect, the second cladding (3) formed on the first cladding and the second cladding (3) are used so as to cover the core. And another substrate (60) bonded to the top of the spacer (71).

  A thirty-eighth aspect is the optical waveguide according to the thirty-seventh aspect, wherein the separate substrate (60) has a recess, and the spacer (71) is fitted in the recess.

  According to a thirty-ninth aspect of the present invention, in an optical waveguide that can be bonded to another substrate (60), a first cladding (2), a core (1) partially formed on the first cladding, and the first cladding A base member (72) partially formed on the top and having a top at a position higher than the height of the core, an alignment mark (70) formed on the top of the base member, and so as to cover the core, An optical waveguide comprising: the second cladding (3) formed on the first cladding.

  A 40th invention is the optical waveguide according to the 39th invention, wherein the alignment mark (70) is formed at a position equal to or higher than the height of the core.

  A forty-first aspect of the invention is the optical waveguide corresponding to the forty-first aspect of the invention, further comprising an optical path conversion mirror formed by depositing a metal on the end of the core, and the alignment mark is the same metal as the optical path conversion mirror It is the optical waveguide formed into a film from.

  A forty-second invention is the optical waveguide according to the forty-first invention, wherein the metal contains at least one of Al, Au, Pt, Ag, Cu, and Ti.

  In a forty-third aspect of the present invention, in the optical waveguide corresponding to the thirty-ninth aspect, an alignment mark (61) is formed at a position facing the alignment mark (70) and bonded onto the second cladding (3). An optical waveguide provided with a substrate (60).

  As described above, according to the present invention, it is possible to provide an inexpensive optical waveguide manufacturing method in which the core material is used efficiently and the core is not easily deformed.

  Hereinafter, embodiments and examples of the present invention will be described in detail with reference to the drawings. The embodiments can be combined with each other, and the first and second embodiments mainly relate to a method for manufacturing an optical waveguide. The third embodiment mainly relates to a case where an external element is mounted. The fourth embodiment mainly relates to a case where a complicated circuit is formed. The fifth embodiment mainly relates to the case of bonding to another substrate. Hereinafter, it will be described in order.

(First embodiment)
FIG. 1 is a process sectional view showing a method of manufacturing an optical waveguide according to the first embodiment of the present invention.

  First, as shown in FIG. 1A, a concave mold 10 having a core pattern-shaped depression and having at least a surface material made of silicone or fluorine resin is prepared. . Further, as shown in FIG. 1B, a substrate 20 is prepared, and a first clad 2 is applied and cured on the substrate 20.

  Then, as shown in FIG. 1C, a core material 1 ′ is sandwiched between the concave mold 10 and the first clad 2 of the substrate 20, and pressure is applied by, for example, a roll 11. Thereby, the core material 1 ′ is confined in the recess.

  Thereafter, as shown in FIG. 1D, for example, the core material 1 ′ is cured by irradiating the ultraviolet rays 12 from the substrate 20 side to form the core pattern 1 corresponding to the recess.

  When the concave mold 10 is peeled off, the core pattern 1 is placed on the first cladding 2 as shown in FIG.

  Even in this state, air acts as a waveguide by acting as an upper clad. However, it is preferable to form the waveguide 7 by covering the core pattern 1 and the first cladding 2 with the second cladding 3 as shown in FIG. In the case of a waveguide without a mirror, the input / output portion of the waveguide 7 is exposed as shown in FIG.

  2 and 3, the waveguide 7 may be formed by using a concave mold 10 having an inclined mirror equivalent surface 4 'in which the end of the core pattern-shaped depression is approximately 45 °. The concave mold 10 is created as shown in FIGS. 4A to 4E, which will be described later. The concave mold 10 is not limited to the configuration having the inclined mirror equivalent surfaces 4 ′ at both ends as shown in FIG. 4 (f), but is an in-plane mirror in the middle of the core pattern-shaped recess as shown in FIG. 4 (g). It may have a corresponding surface 5 ′.

  When the concave mold 10 having the inclined mirror equivalent surface 4 ′ as shown in FIG. 4 (f) is used when forming the waveguide 7, as shown in FIGS. An oblique mirror surface 4 for optical path conversion can be formed at the end of the core pattern 1.

  Further, when the concave mold 10 having the in-plane mirror equivalent surface 5 ′ as shown in FIG. 4G is used, as shown in FIG. The conversion mirror surface 5 can be formed.

  Here, a method of manufacturing the concave mold 10 will be described.

  First, as shown to (a)-(c) of FIG. 4, the convex part of a core pattern shape is formed on the board | substrate 31. FIG. The core pattern shape can be easily produced by applying a photosensitive resin 32 (for example, a photoresist) on the substrate 31 and exposing and developing.

  An inclined mirror equivalent surface 4 ′ of approximately 45 ° for optical path conversion can be formed at the end of the core pattern. Specifically, the oblique mirror equivalent surface 4 ′ is formed by laser processing in which a laser beam 33 is incident obliquely, as shown in FIG. For laser processing, KrF excimer laser, ArF excimer laser, femto second laser, UV-YAG laser, etc., laser light having a wavelength in the ultraviolet region that can cut molecules with high energy of photons. 33 is used. An in-plane mirror equivalent surface 5 ′ for in-plane optical path conversion can be formed in the middle of the core pattern. This in-plane mirror equivalent surface 5 'may be produced by exposure and development simultaneously with the production of the core pattern shape, or may be produced by laser processing after the production of the core pattern shape.

  As described above, as shown in FIG. 4C, the convex mold 30 having the convex portions having the inclined mirror equivalent surfaces 4 'at both ends is formed.

  Next, as shown in FIG. 4D, the concave mold 10 is produced by filling and curing the liquid silicone or fluororesin 34 in the convex mold 30. The liquid silicone or fluororesin 34 can be cured at room temperature or by heating.

  When the curing is completed, the concave mold 10 can be formed as shown in FIG.

  According to the shape of the convex mold 30, the concave mold 10 has a mirror equivalent surface 4 ′ or 5 ′ formed in the core pattern-shaped depression as shown in FIG. 4 (f) or (g).

  Returning to the discussion of waveguide fabrication. As shown in FIG. 2, when the waveguide 7 is formed using the concave mold 10 having the inclined mirror equivalent surface 4 ′, the mirror surface 4 or 5 of the core pattern 1 is formed on the mirror surface 4 or 5 as shown in FIG. It is desirable to provide the reflective film 6. The reflective film 6 is preferably a metal (for example, Al, Ag, Cu, etc.), but may be a multilayer film. As a formation method, various methods such as a mask vapor deposition method, an (after the entire film formation) etching method, a lift-off method, and the like are applicable.

  Alternatively, as shown in FIG. 3, when the reflective film 6 is formed in advance on the mirror equivalent surface 4 ′ or 5 ′ of the concave mold 10 and the concave mold 10 is peeled from the core pattern 1, the mirror equivalent surface of the core pattern 1. It is also possible to transfer the reflective film 6 to 4 or 5.

  As the cladding 2 or 3, epoxy is preferably used. As a method for curing the clad 2 or 3, ultraviolet curing, heat curing, or a combination of both can be used.

  Note that a press roll is preferable as a method of sandwiching the core material 1 ′. That is, the area is moved by the rotation of the roll 11 while applying pressure by the roll 11. The core material 1 ′ can be confined in the core pattern-shaped recess by the press roll, and it is possible to prevent bubbles from remaining. 1 to 3, the concave mold 10 is on the bottom. However, the orientation is not limited to this, and the substrate 20 may be on the bottom, for example.

  As shown in FIG. 7, the angle θ formed by the substrate movement direction 11a of the press roll and the main straight line portion of the waveguide is preferably as small as possible. Further, a case will be described in which a linear waveguide has two main linear portions orthogonal to each other as shown in FIG. In this case, as shown in FIG. 8, the angle between the two directions of the linear waveguide and the substrate movement direction 11a of the press roll is set to approximately 45 °, whereby satisfactory embedding can be achieved.

  As the core material 1 ′, epoxy or acrylic resin is preferably used. As a method for curing the core, ultraviolet curing, thermal curing, or a combination of both is possible. In particular, ultraviolet curing is important for obtaining good dimensional accuracy because temperature changes can be minimized.

  Further, in order to obtain better dimensional accuracy, it is necessary to suppress curing shrinkage of the concave mold 10. For this purpose, it is effective to use a concave mold 10 having a backing material 15 as shown in FIG. 9A. If a material having a smaller thermal expansion coefficient than the resin 34 of the concave mold 10 is used as the backing material 15, for example, an inorganic material such as a metal, a dimensional change due to a temperature change during core curing can be suppressed. Most preferably, the thermal expansion coefficient of the backing material 15 is matched with the thermal expansion coefficient of the substrate 20 with the clad 2.

  In order to use such a concave mold 10, it is important to irradiate the ultraviolet rays 12 from the substrate 20 side when the core is cured. The reason is that a metal suitable for the backing material 15 is difficult to transmit the ultraviolet rays 12. The substrate 20 needs to be an ultraviolet ray transmissive substance. For example, glass is suitable as the ultraviolet transmissive substance.

  In addition, when the core material 1 ′ is sandwiched, as shown in FIG. 10A, strictly, the core 13 that remains thin is present in the entire portion other than the core pattern 1. The thickness of the remaining core 13 can be reduced to about 1 μm by optimization, and there is almost no problem with optical waveguide. However, when the interval between the adjacent core patterns 1 is narrow, the core 13 causes cross talk.

  In that case, as shown in FIG. 10B, after the concave mold 10 is peeled off, the thin remaining core 13 is removed. For example, the core 13 can be removed by treating the whole with an oxygen plasma. Alternatively, the whole may be lightly treated with chemicals. Thereby, even when the interval between adjacent core patterns 1 is narrow, crosstalk can be reduced. Further, since the thin remaining core 13 is only about 1 μm, it can be removed in a short time and the manufacturing load is small.

  As shown in FIG. 11B, when the release layer 14 is formed on the substrate 20 in advance and the substrate 20 is removed from the release layer 14 after the waveguide 7 is manufactured, the process shown in FIG. As shown, the waveguide 7 can be made into a film.

  When irradiating with ultraviolet rays from the substrate 20 side in the core curing, the release layer 14 desirably transmits the ultraviolet rays 12. As the release layer 14, a thin photoresist layer, a water-soluble adhesive, or the like can be used.

  Next, Examples 1 to 9 of the first embodiment as described above will be described. Here, Examples 1, 4, and 9 relate to a concave type, and Examples 2, 3, and 5 relate to an optical waveguide. Examples 6 and 7 relate to the direction of the press roll and the waveguide. Example 8 relates to film formation of a waveguide. The following will be described sequentially.

<Example 1>
[Concave type 1]
Example 1 of the first embodiment will be described with reference to FIG. First, as shown in FIG. 4 (a), a dry film resist is attached on a substrate 31 (glass), exposed and developed to form a photosensitive resin 32 pattern in cross section. Formed a waveguide-like convex pattern of 40 μm square.

  Next, as shown in FIG. 4 (b), an oblique mirror equivalent surface 4 ′ is produced by obliquely irradiating a KrF excimer laser as the laser light 33, and a convex shape as shown in FIG. 4 (c). 30 was formed.

  Then, as shown in FIG. 4D, a liquid silicone resin 34 was layered on the convex mold 30 and cured at room temperature. Thereafter, the convex mold 30 was peeled from the silicone resin 34 to produce the concave mold 10 as shown in FIG.

<Example 2>
[Optical waveguide 1]
Example 2 of the first embodiment will be described with reference to FIG. First, as shown to (a) of FIG. 2, the concave mold 10 (silicone resin) produced in Example 1 is prepared.

Next, a substrate 20 (glass) was prepared, and an ultraviolet curable epoxy resin as a clad material was spin coated on the substrate 20. The clad material was cured by irradiating the entire surface of the substrate with ultraviolet rays of 4 J / cm ² , and a film of the first clad 2 having a thickness of 30 μm was formed on the substrate 20 as shown in FIG.

  Then, an ultraviolet curable epoxy resin was dropped on the concave mold 10 as the core material 1 ′. As shown in FIG. 2C, the substrate 20 with the clad 2 was placed on the concave mold 10 and passed through a roll laminater.

  The concave mold 10 and the substrate 20 with the clad 2 were pressed by the roll 11, and the core material 1 ′ was embedded in the recess of the concave mold 10.

As shown in FIG. 2D, by irradiating 8 J / cm ² of ultraviolet rays 12 from the substrate 20 side in this state, the core material 1 ′ was cured and the core pattern 1 was formed.

  As shown in FIG. 2E, the concave mold 10 was peeled off, and as shown in FIG. 2F, Al was mask-deposited on the oblique mirror surface 4 of the core pattern 1 as the reflective film 6.

Further, an ultraviolet curable epoxy resin was applied as the second clad 3 and the entire surface was irradiated with ultraviolet rays of 4 J / cm ² to complete the waveguide 7 as shown in FIG.

<Example 3>
[Optical waveguide 2]
Example 3 of the first embodiment will be described with reference to FIG. First, as shown in FIG. 3A, the concave mold 10 (silicone resin) prepared in Example 1 is prepared, and as shown in FIG. 6, Al was mask-deposited. Thereafter, similarly to (b) to (d) of FIG. 2 described above, the core pattern 1 was formed on the first cladding 2 as shown in (c) to (e) of FIG. However, an ultraviolet curable acrylic resin was used as the core material 1 ′.

  Next, when the concave mold 10 is peeled off, as shown in FIG. 3 (f), Al that is the reflection film 6 on the oblique mirror equivalent surface 4 ′ of the concave mold 10 is transferred to the oblique mirror surface 4 of the core pattern 1. did. Thereafter, as described above, as shown in FIG. 3G, the second cladding 3 was formed, and the waveguide 7 was completed.

<Example 4>
[Concave type 2]
Example 4 of the first embodiment will be described with reference to FIG. First, as shown in FIG. 4A, an ultraviolet curable epoxy was applied on a substrate 31 (glass), exposed, and subjected to solvent development to form a pattern of convex portions of the photosensitive resin 32.

  This pattern has a waveguide shape with a cross section of 40 μm square. The pattern was provided with not only a straight line but also an in-plane mirror equivalent surface 5 '(not shown).

  Next, as shown in FIG. 4B, an oblique mirror equivalent surface 4 ′ was formed by obliquely irradiating the pattern of the photosensitive resin 32 with a femtosecond laser as the laser light 33. Thereby, as shown in (c) of Drawing 4, convex mold 30 was obtained.

  Then, as shown in FIG. 4D, the liquid fluororesin 34 is stacked on the convex mold 30 and thermally cured, and the fluororesin 34 is peeled from the convex mold 30, so that it is shown in FIG. Thus, the concave mold 10 of fluororesin was produced.

<Example 5>
[Optical waveguide 3]
Example 5 of the first embodiment will be described with reference to FIG. In Example 5, as shown in FIG. 2 (a), the concave mold 10 (fluororesin) produced in Example 4 was prepared, and the concave mold 10 was used to convert the concave mold 10 into (b) to (g) of FIG. As shown, the waveguide 7 is created in the same manner as in the second embodiment.

<Example 6>
[Press roll and waveguide direction 1]
As shown in FIG. 4F, a concave mold 10 having a linear core pattern shape was used.

  In FIG. 2C and FIG. 7 of Example 2, a test was performed by changing the angle θ between the direction of the linear depression of the concave mold 10 and the conveyance direction by the roll laminator.

  When the angle θ = 0 °, 30 °, and 45 °, the core material 1 ′ was successfully embedded. When the angle θ = 60 °, a small amount of bubbles was observed. When the angle θ was 90 °, a large amount of bubbles was observed.

<Example 7>
[Press roll and waveguide direction 2]
A concave mold 10 having two orthogonal straight lines and an in-plane mirror equivalent surface 5 ′ connecting them was used as shown in FIG.

In FIG. 2C of Example 2, the press roll was performed in such a direction that the direction of the linear depression of the concave mold 10 and the conveying direction by the roll laminator were approximately 45 °.
As a result, the core material 1 ′ was successfully embedded.

<Example 8>
[Film]
FIG. 11 (a) is the same as FIG. 2 (a). Next, as shown in FIG. 11B, after applying 1 μm of a positive resist as a release layer 14 on the substrate 20 and heating, as shown in FIGS. 11C to 11H. A waveguide 7 was manufactured by the same method as in Example 2.

  By immersing the completed waveguide 7 in a stripping solution, the stripping layer 14 was dissolved and the waveguide 7 was made into a film as shown in FIG.

  With respect to the film-like waveguide 7, infrared light having a wavelength of 0.85 μm was incident on the oblique mirror surface 4 at one end through a fiber, and emission from the oblique mirror surface 4 at the other end was confirmed.

<Example 9>
[Concave 3]
First, the convex mold 30 was formed in the same manner as in Example 1. Next, a liquid silicone resin 34 was stacked on the convex mold 30, and a stainless plate as a backing material 15 was stacked.

  In this state, the silicone resin 34 was cured at room temperature, and the convex mold 30 was peeled off to produce the concave mold 10 as shown in FIG. 9A.

  Then, using the concave mold 10 with the backing material 15, the waveguide 7 was manufactured in the same manner as in Example 2. The core pattern 1 of the waveguide 7 has almost the same dimensions as the mask pattern.

  On the other hand, as shown in FIG. 9B, the core pattern 1 produced using the concave mold 10 without the backing as in Example 2 was contracted by about 0.5% compared to the mask pattern.

  As described above, according to the first embodiment and Examples 1 to 9 thereof, the following effects can be obtained.

  First, the deformation of the core pattern 1 can be reduced by using silicone or fluororesin 34 as the concave mold 10. Further, since the core material resin 1 ′ is sandwiched in the recess of the concave mold 10, the core material can be used efficiently and can be formed at low cost.

  Second, by using the concave mold 10 having the mirror surfaces 4 and 5, the mirror surfaces 4 and 5 can be formed simultaneously with the formation of the core pattern 1.

  Thirdly, since the core 1 remaining on the entire surface after peeling the concave mold 10 is thin, the remaining core 1 can be easily removed.

(Second Embodiment)
FIG. 12 is a cross-sectional view showing an example of a method for manufacturing an optical waveguide according to the second embodiment of the present invention. First, as shown in FIG. 12A, the concave mold 10 is prepared.

  The concave mold 10 serves as a mold when forming the optical waveguide. Not only the core pattern of the optical waveguide but also a portion corresponding to a mirror and an optical circuit such as a diffraction grating, a branch circuit, and an array waveguide diffraction grating can be incorporated into the pattern-shaped recess of the concave mold 10.

  As a material of the concave mold 10, a silicone resin is suitable. This is because the silicone resin is flexible, so that the core pattern is easily bonded and peeled off when it is transferred to another clad substrate, and the core pattern is not easily damaged.

  The concave mold 10 may be entirely made of a silicone resin, and at least the surface having the pattern-shaped concave portion is preferably a silicone resin.

  Next, as shown in FIG. 12B, the concave mold 10 is subjected to a surface treatment. The affinity for the core material 1 ′ of the concave mold 10 can be increased by the surface treatment. Specifically, the core material 1 ′ can be stably embedded in the concave mold 10 by setting the contact angle of the core material 1 ′ to 45 ° or less. As the surface treatment, oxygen plasma treatment is suitable.

  Next, as shown in FIGS. 12C to 12D, only the pattern-shaped concave portion of the substrate is filled with the core material 1 '. As the core material 1 ′, for example, an epoxy resin, particularly an ultraviolet curable epoxy resin is suitable.

  As a filling method, a method of scraping off an excess core material using a blade after applying the entire surface, for example, a method of scraping using a spatula 46 as a blade is possible. Then, the core material 1 ′ is cured by ultraviolet irradiation to form the core pattern 1.

  Here, as shown in FIG. 12E, the substrate 20 is prepared, and the clad material 2 ′ is applied to the entire surface of the substrate 20. Then, as shown in FIG. 12 (f), the concave mold 10 on which the core pattern 1 is formed and another substrate 20 coated with the clad material 2 ′ are overlapped. In this state, the clad material 2 ′ is cured by irradiating with ultraviolet rays to form the first clad 2. Thereafter, the concave mold 10 is peeled off and the core pattern 1 is transferred to the substrate 20 side.

  As the cladding material 2 ', for example, an ultraviolet curable epoxy resin is suitable. Further, the curing method of the core material 1 ′ and the clad material 2 ′ is not limited to curing by ultraviolet irradiation.

  As shown in FIG. 12G, the optical path conversion mirror is formed as metal mirrors 4 and 6 by depositing metal on the inclined surface 4 of the core pattern 1. In order to attach metal only to the inclined surface, a mask vapor deposition method or a lift-off method can be used. The optical path conversion mirror is not limited to the configuration that converts the optical path in the direction perpendicular to the optical waveguide layer as shown in FIG. 5, but the optical path conversion at an arbitrary angle within the plane of the optical waveguide layer as shown in FIG. It is also possible to use a configuration that does this.

  Next, as shown in FIG. 12 (h), the clad material 3 'is applied to the entire surface and cured to form the second clad 3, whereby the single-layer optical waveguide 7 is completed. Alternatively, air can be substituted for the clad without providing the second clad 3.

  Further, as shown in FIG. 13, before the clad material 3 is cured, the core pattern 1A is formed on another concave mold 10A and transferred, whereby the optical waveguide 7 having a multilayer structure can be formed. (H) in FIG. 13 corresponds to (h) in FIG.

  When forming the multilayer optical waveguide 7 or when transferring the single-layer or multilayer optical waveguide 7 to another substrate (eg, electrical wiring substrate), alignment marks (on the substrate 20 or the first cladding 2) It is desirable to provide a not-shown).

  Further, when the single-layer or multilayer optical waveguide 7 is used as a film, a release layer (not shown) is provided between the substrate 20 and the clad material 2, and the optical waveguide is manufactured and then released to form a film. Is desirable. The substrate 20 and the release layer or the concave mold 10 are desirably transparent to ultraviolet rays.

  For the manufacture of the concave mold 10, as shown in FIG. 4, a method in which the convex mold 30 is produced and the mold is made with the silicone resin 34 or the like can be used.

  The aspect ratio (height / width) of the core pattern is usually about 1. In this case, the mirror that changes the optical path in the direction perpendicular to the optical waveguide layer is substantially square when viewed from above, and is approximately the same in the XY direction of the component alignment request. However, even if the aspect ratio is not 1, there is no problem with wave guiding. In fact, the present inventor has confirmed the waveguide at an aspect ratio of 0.27 to 2.

  Further, instead of filling the core material 1 ′ only in the pattern-like recesses and overlapping with the separate substrate 20 with the clad material after curing, the core material 1 ′ is placed between the concave substrate 10 and the clad substrate 20 as shown in FIG. It is also possible to produce a waveguide by sandwiching. That is, the concave mold 10 is prepared as shown in FIG. 14A, and surface treatment is performed as shown in FIG. Next, as shown in FIG. 14C, a substrate 20 with a clad 2 is prepared, and as shown in FIG. 14D, the core material 1 ′ is sandwiched between the concave mold 10.

  As shown in FIG. 14E, the core material 1 ′ is cured by a method such as ultraviolet irradiation from the substrate 20 side and / or the concave mold 10 side to form the core pattern 1. The concave mold 10 is peeled off, and the core pattern 1 is transferred to the substrate 20 side. And as shown to (f) of FIG. 14, metal is vapor-deposited on the inclined surface of the core pattern 1, and it is set as the metal mirrors 4 and 6. FIG. Normally, the core pattern 1 and the first cladding 2 are covered with the second cladding 3 as shown in FIG. Also in this case, stable core formation is possible by surface treatment. Also, this method can form a multilayer optical waveguide.

  Furthermore, not only the concave mold 10 but also a convex mold 16 can be used as a mold as shown in FIG. For example, as shown in FIGS. 15A to 15E, the clad 2 having a pattern-like concave portion is manufactured by molding using a convex die 16 subjected to surface treatment. Next, as shown in FIGS. 15 (f) to 15 (i), after forming the metal mirror 6 on the inclined surface of the recess, the core 1 is buried and covered with the clad 3 to produce a waveguide.

  Below, the manufacturing method of the optical waveguide by this invention is demonstrated in detail in Examples 10-13.

<Example 10>
[Production of concave mold]
The concave mold 10 was produced as shown in FIG. However, the convex pattern 32 on the substrate 31 before being molded was formed into a plurality of optical waveguide shapes having a height of 40 μm and a width of 20 μm to 150 μm.

[Production of Optical Waveguide 1]
This will be described with reference to FIGS. First, as shown in FIG. 12A, a concave mold 10 (silicone resin) was prepared. Next, as shown in FIG. 12B, oxygen plasma treatment was performed on the substrate having the pattern-shaped recesses. The apparatus used is OPM-SQ600 (model number) manufactured by Tokyo Ohka Kogyo Co., Ltd. The oxygen flow rate was 100 SCCM, the pressure was 60 Pa, the plasma power was 100 W, and the time was 2 minutes.

  Then, as shown in FIGS. 12C to 12D, an ultraviolet curable epoxy resin was applied to the entire surface as the core material 1, and the core material 1 ′ other than the recesses was scraped off with a spatula 46. By irradiating the entire surface with ultraviolet rays, the core material 1 ′ was cured to form the core pattern 1.

  As shown in FIG. 16, the core pattern 1 was able to continuously form all types of core widths of 20 μm to 150 μm without any problem.

  On the other hand, as shown in FIG. 12 (e), another substrate 20 (glass) was prepared, and an ultraviolet curable epoxy resin was spin-coated as a clad material 2 'on the entire surface.

  Here, as shown in FIG. 12 (f), the core pattern 1 ′ and the clad material 2 ′ are brought into close contact with each other by irradiating ultraviolet rays from the side of the separate substrate 20 with the two 10 and 2 being overlapped. Then, the clad material 2 ′ was cured to obtain a clad 2.

  As shown in FIG. 12G, after the concave mold 10 was peeled off, metal Al was vapor-deposited on the inclined surface by mask vapor deposition to form metal mirrors 4 and 6. Further, as shown in FIG. 12 (h), the entire surface was coated with an ultraviolet curable epoxy resin as a clad material 3 'and irradiated with ultraviolet rays to complete the optical waveguide 7.

<Example 11>
[Fabrication of optical waveguide 2]
The contact angle of the core material on the silicone was measured by changing the oxygen plasma treatment conditions such that the oxygen flow rate was 100 SCCM and the pressure was constant at 60 Pa, the plasma power was 20 W to 400 W, and the time was 1 second to 10 minutes.

  As shown in FIG. 17, it was confirmed that the contact angle of silicone was about 60 ° when not treated, but changed to about 40 ° to 25 ° when oxygen plasma treatment was performed. Then, using any of the concave molds 10 subjected to the oxygen plasma treatment shown in FIG.

<Example 12>
[Fabrication of optical waveguide 3]
This will be described with reference to FIG. First, in the same manner as in Example 10, a concave mold 10 was prepared as shown in FIG. 14A, and oxygen plasma treatment was performed on the concave mold as shown in FIG. 14B.

  On the other hand, as shown in FIG. 14 (c), a substrate 20 (glass) is prepared, and the entire surface is spin-coated with an ultraviolet curable epoxy resin as a clad material 2 ′ and irradiated with ultraviolet rays to form the first clad 2. .

  Then, as shown in FIGS. 14D to 14E, the core material 1 ′ is sandwiched between the concave mold 10 and the substrate 20 with the clad 2, and the core pattern is irradiated by irradiating ultraviolet rays from the substrate 20 side. 1 was formed.

  After removing the concave mold 10, as shown in FIG. 14 (f), metal Al was deposited on the inclined surface by mask deposition to form metal mirrors 4 and 6. Further, as shown in FIG. 14 (g), an ultraviolet curable epoxy resin was applied to the entire surface as a clad material 3 'and cured with ultraviolet rays to complete the optical waveguide 7.

<Example 13>
[Fabrication of optical waveguide 4]
This will be described with reference to FIG. First, as shown in FIG. 15A, a convex mold (silicone) 16 is prepared by a method similar to Example 10, and as shown in FIG. 15B, the convex mold 16 is subjected to oxygen plasma treatment. Went.

  On the other hand, as shown in FIG. 15C, a substrate 20 (glass) was prepared, and an ultraviolet curable epoxy resin as a clad material 2 'was spin coated on the entire surface. Next, as shown in FIG. 15 (d), this clad material 2 ′ was placed on the convex mold 16 and irradiated with ultraviolet rays to form the clad 2.

  Then, as shown in FIG. 15 (e), the convex mold 16 was peeled off, and as shown in FIG. 15 (f), metal Al was deposited on the inclined surface by mask deposition to form metal mirrors 4 and 6.

  Further, as shown in FIGS. 15 (g) to 15 (h), an ultraviolet curable epoxy resin was applied over the entire surface as the core material 1 ′, and the core material 1 ′ other than the recesses was scraped off with a spatula 46. By irradiating the entire surface with ultraviolet rays, the core material 1 ′ was cured to form the core pattern 1.

  Finally, as shown in FIG. 15 (i), an ultraviolet curable epoxy resin was applied to the entire surface as a clad material 3 'and cured with ultraviolet rays to complete the optical waveguide 7.

<Comparative Example 1>
[Fabrication of optical waveguide 5]
This will be described with reference to FIG. First, as in Example 10, a substrate 10 (silicone resin) having a pattern-shaped recess as shown in FIG.

  Next, as shown in FIGS. 18B to 18C, without performing the surface treatment of Example 10, an ultraviolet curable epoxy resin was applied to the entire surface as the core material 1 ′, and the spatula 46 was used to apply a portion other than the concave portion. The core material 1 ′ was scraped off. By irradiating the entire surface with ultraviolet rays, the core material 1 ′ was cured to form the core pattern 1.

  At this time, the core pattern 1 having a core width of 100 μm or more could be formed without any problem. However, as shown in FIG. 18C, the core pattern 1 having a core width of 50 μm or less is likely to be disconnected, and it is difficult to form a continuous waveguide.

  As described above, according to the second embodiment and Examples 10 to 13, since the substrate is subjected to the surface treatment that increases the affinity of the core material before filling only the pattern-shaped concave portion of the substrate with the core material, it is stable. The core pattern thus formed can be easily formed. In addition, since the inclined surface serving as the optical path conversion mirror is provided in the core pattern, it is not necessary to form the inclined surface again. For this reason, the vapor deposition of the metal to an inclined surface can be performed in the process continuous with the manufacturing process of the core pattern. Moreover, the use efficiency of a core material is good like 1st Embodiment.

  As described above, a stable polymer optical waveguide can be manufactured at low cost.

(Third embodiment)
Next, a third embodiment of the present invention will be described. In the third embodiment, connection efficiency is improved by connecting to the core 1 while converting light from the light source into substantially parallel light. When the plane mirrors 4 and 6 as shown in FIG. 47 are used, the light from the light emitting element 40 is incident on the core 1 with an angular distribution, so that the signal light 8 travels with an angle and is emitted at the time of emission. Bring a big spread.

  On the other hand, as shown in FIG. 19, the focal point of the concave mirror is made to substantially coincide with the light emitting point of the light emitting element 40 arranged in the vertical direction of the optical waveguide. Thereby, the light reflected by the concave mirrors 4 and 6 enters the core as substantially parallel light, so that the spread of the emitted light is small and the connection efficiency from the core to the light receiving element is improved.

  Since FIG. 19 is a cross-sectional view, only the light condensing in the paper surface is shown. However, by making the concave surface also in the direction perpendicular to the paper surface, the component perpendicular to the paper surface has a light condensing action. It should be noted that the condensing of either one in the plane of the paper or in the direction perpendicular to the plane of the paper has a partial effect and is included in the present invention. When the radius of curvature of the concave mirror is 300 μm, the focal length is about 100 μm. Also, “substantially coincide” means that the error is within 30%.

  Usually, the term “focal length” means the distance from the center of the mirror to the point where the reflected light is collected from the direction perpendicular to the mirror. However, the term “focal length” according to the present embodiment refers to the distance from the center of the mirror to the point where the reflected light is collected from the direction inclined by 45 ° with respect to the direction perpendicular to the mirror. is there. This focal length can be measured, but can also be calculated from the shape of the mirror.

  Further, in the present embodiment, it is possible to increase the positional deviation margin of the light receiving element 41 by irradiating the light receiving element while condensing the light from the core 1. That is, as shown in FIG. 20, when the concave mirrors 4 and 6 are used and the focal length 9 of the concave mirror is set to 1/2 or more of the distance to the light receiving element 41 installed in the vertical direction of the optical waveguide, the light 8 is generated. Since it enters the light receiving element 41 in a condensed state, a positional deviation margin increases. In particular, when the focal length is substantially equal to the distance to the light receiving element, the positional deviation margin can be maximized.

  Since FIG. 20 is a cross-sectional view, only the light condensing in the paper surface is shown. However, by making the concave surface also in the direction perpendicular to the paper surface, the component perpendicular to the paper surface has a light condensing action. It should be noted that light collection in only one of the direction in the plane of the paper and the direction perpendicular to the plane of the paper has a partial effect and is included in the present invention.

  When the focal length 9 is set to ½ or less of the distance to the light receiving element 41, the light diverges, and the positional deviation margin or the connection efficiency is reduced. Also, “substantially coincide” means that the error is within 30%.

  Usually, the term “focal length” often means the distance from the center of the mirror to the point where the reflected light is collected from the direction perpendicular to the mirror. However, the term “focal length” according to the present embodiment refers to the distance from the center of the mirror to the point where the reflected light is collected from the direction inclined by 45 ° with respect to the direction perpendicular to the mirror. means. This focal length can be measured, but can also be calculated from the shape of the mirror. The positions of the elements 40 and 41 can be easily adjusted according to the dimensions of the electrodes or spacers 42 and 43.

  Here, a method for easily producing an optical waveguide having a concave mirror will be described. First, as shown in FIG. 21A, a prototype having a core-patterned photosensitive resin 32 having a mirror-equivalent surface (convex surface) 4 'at an end portion on a substrate 31 is manufactured.

  Next, as shown in FIG. 21 (b), a concave mold 10 having at least a surface made of a silicone resin is produced based on the original mold. Then, an optical waveguide is produced from the concave mold.

  Specifically, as shown in FIG. 21 (c), a method for producing an optical waveguide from the concave mold is obtained by sandwiching a liquid core material 1 ′ between the substrate 20 with the clad 2 and the concave mold, as shown in FIG. As shown in (d), it is cured, and as shown in (e) of FIG. 21, the concave pattern is peeled off to form a core pattern having a mirror surface 4.

  Next, as shown in FIG. 21F, the reflective film 6 is formed on the mirror portion. Furthermore, as shown in FIG. 21 (g), the whole is covered with the clad 3.

  By this method, it is possible to form a core pattern having an oblique convex portion at the end. This oblique convex portion becomes a concave mirror. A convex surface when viewed from the outside is a concave surface for light passing through the core pattern. The reflective film may be a metal or a dielectric multilayer film. However, metals that are not affected by the film thickness distribution are easier to use.

  Next, three methods for producing a prototype having an oblique convex portion will be described as first to third methods.

  In the first method, for example, a resist pattern of a photosensitive resin is formed by photolithography. Thereafter, as shown in FIGS. 22A to 22C, the end portion of the photosensitive resin 32 on the substrate 31 is irradiated with a laser beam 33 having a substantially circular shadow through a mask. Thereby, the mirror equivalent surface 4 ′ is produced by evaporating the end of the photosensitive resin 32. Therefore, it is possible to collect light in a direction perpendicular to both optical axes. The term “having a substantially circular shadow” means that the outside of the approximately circular shadow is a light irradiation region. The approximate circle includes an arbitrary curve such as a quadratic curve.

  In the second method, as shown in FIG. 23A, after a resist pattern is formed by photolithography, as shown in FIGS. 23B to 23F, a plurality of different directions are formed at the resist end. A slanted convex part is produced by performing laser processing of times. As shown in FIG. 23, the rectangular laser beam 33 may be irradiated many times. However, as shown in FIGS. 24A to 24D, the laser beam 33 having a substantially circular shadow is used. You can do it a few times.

  In the third method, as shown in FIG. 25A, a resist pattern is formed by photolithography. Thereafter, as shown in FIGS. 25B to 25C, an oblique surface is formed by laser processing. Subsequently, as shown in FIG. 25D, the temperature is further raised to cause the resist to flow and deform into a convex shape. The resist may be a positive type or a negative type.

<Example 14>
[Laser processing with roughly circular shadow]
Example 14 according to the third embodiment will be described with reference to FIG. As shown in FIG. 22A, a dry film resist was bonded onto a substrate 31 (glass), and a photosensitive resin 32 was formed in a core pattern shape having a 40 μm square cross section by exposure and development.

  Next, the KrF excimer laser beam 33 is irradiated obliquely. At that time, as shown in FIG. 22B, the laser beam 33 is shaped into a beam shape having a substantially circular shadow using a mask. Thereby, as shown in FIG. 22C, a convex oblique mirror equivalent surface 4 ′ was produced, and a convex mold 30 was obtained. The radius of curvature of the circular shadow of the laser beam 33 used was 300 μm, and the radius of curvature of the processed resist was approximately 300 μm.

<Example 15>
[Multiple irradiation]
Example 15 according to the third embodiment will be described with reference to FIG. As shown in FIG. 24A, a dry film resist was bonded onto a substrate 31 (glass), and a photosensitive resin 32 was formed into a core pattern shape having a cross section of 40 μm square by exposure and development.

  Next, the KrF excimer laser beam 33 is irradiated obliquely. At that time, as shown in FIG. 24B, a laser beam 33 was shaped into a beam shape having a substantially circular shadow using a mask, and the first laser processing was performed.

  Next, as shown in FIG. 24C, the second laser processing is performed by changing the angle of oblique irradiation by 10 °. Thereby, as shown in FIG. 24D, a convex oblique mirror equivalent surface 4 ′ was produced, and a convex mold 30 was obtained. The radius of curvature of the circular shadow of the laser beam 33 used was 300 μm, and the radius of curvature of the processed resist was almost 300 μm.

<Example 16>
[Reflow]
Example 16 according to the third embodiment will be described with reference to FIG. As shown in FIG. 25A, a liquid resist was applied on a substrate 31 (glass), and a photosensitive resin 32 pattern was formed into a core pattern shape having a cross section of 40 μm square by exposure and development.

  Next, the KrF excimer laser beam 33 is irradiated obliquely. At this time, as shown in FIG. 25 (b), the laser beam 33 has a rectangular beam shape, and the photosensitive resin 32 is processed into an oblique plane. Next, by performing heat treatment at 130 ° C. for 10 minutes, the photosensitive resin 32 flowed and changed to a convex oblique mirror equivalent surface 4 ′ as shown in FIG. The radius of curvature of the processed resist was approximately 300 μm.

<Example 17>
[Fabrication of optical waveguide]
As shown in FIG. 21 (b), as shown in FIG. 21 (a), a liquid silicone resin 34 is layered on the convex mold 30 produced by the method of Example 15 and cured at room temperature, followed by peeling. A concave mold 10 was produced.

Next, the substrate 20 (glass) was prepared, and an ultraviolet curable epoxy resin was spin-coated as the clad material 2 ′. By irradiating the entire surface with ultraviolet rays of 4 J / cm ² , the clad material 2 ′ was cured to form a 30 μm thick film (not shown).

Then, as shown in FIG. 21 (c), an ultraviolet curable epoxy resin was dropped onto the concave mold 10 as the core material 1 ', and the substrate 20 with the clad 2 was stacked and pressed. As shown in FIG. 21 (d), the core material 1 ′ was embedded in the recess of the concave mold 10. In this state, the core material 1 ′ was cured to the core pattern 1 by irradiating the substrate 12 with the ultraviolet rays 12 of 8 J / cm ² . As shown in FIG. 21E, the concave mold 10 was peeled off, and as shown in FIG. 21F, Al was mask-deposited on the oblique mirror surface 4 of the core pattern 1 as the reflective film 6. As shown in FIG. 21 (g), an ultraviolet curable epoxy resin was further applied as the second cladding 3 ′, and the entire surface was irradiated with ultraviolet rays of 4 J / cm ² to complete the optical waveguide 7.

<Example 18>
[Evaluation of incident side mirror]
By the method of Example 17, an optical waveguide including a core having a concave mirror at one end and a plane mirror at the other end was produced. A VCSEL (surface emitting laser) having a wavelength of 850 nm was installed at a position 100 μm from the center of the optical waveguide on the concave mirror side (50 μm from the waveguide surface).

  On the other hand, a PD having a diameter of 80 μm was installed at a position 100 μm from the center of the optical waveguide on the plane mirror side (50 μm from the waveguide surface).

  The gap between the VCSEL and the optical waveguide and between the optical waveguide and the PD was sealed with a transparent resin having a refractive index substantially equal to that of the cladding.

  The optical signal from the VCSEL was emitted to the PD through the optical waveguide in the order of the concave mirror, the inside of the core, and the plane mirror. The signal light received by the PD has a signal strength that is 1.5 times that of the case where both ends of the core are plane mirrors.

<Example 19>
[Evaluation of output side mirror]
An optical waveguide including a concave mirror core at both ends was produced by the method of Example 17. At both ends of the core, a VCSEL having a wavelength of 850 nm and a PD having a diameter of 80 μm were installed at a position of 100 μm from the center of the core (50 μm from the surface of the optical waveguide).

  The space between the VCSEL and the optical waveguide was sealed with a transparent resin having a refractive index substantially equal to that of the cladding. The space between the optical waveguide and PD was filled with a liquid whose refractive index was almost equal to that of the cladding.

  The signal light from the VCSEL passed through the optical waveguide in the order of the concave mirror at one end, the inside of the core, and the concave mirror at the other end in this order, and was emitted to the PD.

  The lateral displacement margin of PD (the amount of positional deviation at which the signal intensity drops to 90%) was 30 μm. On the other hand, the margin of misalignment when the exit side is a plane mirror was 10 μm.

  As described above, according to the third embodiment and Examples 14 to 19, the following effects can be obtained.

  First, the connection efficiency and misalignment allowance can be increased by a simple structure using a concave mirror as an optical path conversion mirror.

  Second, a core having a concave mirror can be easily manufactured by using a mold.

  Third, a core mold having a concave mirror can be produced by using laser processing having a substantially circular shadow, laser processing multiple times, or reflowing.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. The fourth embodiment is for easily mounting the optical waveguide described in the first to third embodiments.

  As shown in FIG. 26, the first point of the fourth embodiment is the extension direction of at least two linear waveguides 45 included in the first core A and at least one of the other cores B. That is, the extending direction of the straight waveguide 45 substantially coincides.

  Here, that the extension directions substantially coincide means that the difference in direction is within 10 °. An in-plane mirror 5 that connects the straight waveguides is provided at the intersection of the two straight waveguides of the first core. Preferably, an oblique mirror 4 connected to an external element is provided at the waveguide end.

  Such a structure has the following merit.

  The first merit is that the area required for the direction change can be reduced by using the in-plane mirror 5.

  The second merit is that the direction of the in-plane mirror 5 can be limited to four types and the conversion angle can be limited to two types by limiting the direction of the straight waveguide 45 to, for example, two types.

  For example, as shown in FIG. 27A, if the extending direction of the linear waveguide 45 is the X direction and the Y direction, the in-plane mirror 5 is “+ X⇔ + Y”, “+ X⇔−Y”, “−X⇔ + Y” and There are four types of “−X⇔−Y”. There are two types of conversion angles because “+ X⇔ + Y” and “−X⇔−Y” are equal, and “+ X⇔−Y” and “−X⇔ + Y” are equal. In addition, as shown in FIG. 27B, the oblique mirror 4 can also be limited to four types of “+ X”, “−X”, “+ Y”, and “−Y”.

  27A and 27B, the X direction and the Y direction are not necessarily orthogonal to each other. However, as shown in FIG. 28A, if the X direction and the Y direction are orthogonal, the conversion angle of the in-plane mirror 5 is one type (90 °). There are four types of oblique mirrors 4 as shown in FIG. 28B.

  Such a structure facilitates processing of the in-plane mirror equivalent surface 5 ′ and the oblique mirror equivalent surface 4 ′.

  For example, when the mirror equivalent surface is collectively processed with a laser, the processing is completed in a total of eight times, four times for the in-plane mirror equivalent surface 5 'and four times for the oblique mirror equivalent surface 4'. If the in-plane mirror equivalent surface 5 ′ is processed by another method, the laser processing may be performed four times.

  On the other hand, even when the mirror-equivalent surface is point-processed one by one with a laser, the sample can be set up only 8 times. When the in-plane mirror equivalent surface 5 ′ is processed by another method, the setting may be performed four times.

  It goes without saying that some patterns are less than that. For example, in FIG. 26, since there are four types of in-plane mirrors and three types of oblique mirrors, the laser processing or setting for producing the prototype is seven times. In addition, when the surface 5 'corresponding to the in-plane mirror is processed by another method, the laser processing or setting may be performed three times.

  On the other hand, in the conventional pattern as shown in FIG. 48, since the curved waveguide 44 is used, the area becomes large, and the direction of the oblique mirror 4 varies, so that the number of times of laser processing or setting increases.

  The second point of the fourth embodiment relates to the core width of the in-plane mirror 5. As shown in FIG. 29, the core 1 is formed on the first clad 2, and the reflection film 6 is formed on the portion that becomes the oblique mirror 4 and the portion that becomes the in-plane mirror 5 at the end of the core 1, and the second clad In the case of the waveguide fabrication method covered with 3, the mirror shape is important.

  At this time, as shown in FIG. 30, the width b projected from the core of the in-plane mirror 5 onto the plane orthogonal to the incident-side linear waveguide 45i is made larger than the core width a of the incident-side linear waveguide 45i. In this case, the loss in the in-plane mirror 5 can be reduced.

  Furthermore, as shown in FIG. 31, even if the core width d of the output-side straight waveguide 45o is made larger than the width c projected from the core of the in-plane mirror 5 onto the surface orthogonal to the output-side straight waveguide 45o. Good.

  The principle will be described. In the waveguide, most of the light enters the core, but part of the light penetrates into the cladding and is guided. Here, when the width b of the core of the in-plane mirror 5 projected onto the plane orthogonal to the incident-side linear waveguide 45i is equal to the core width a of the incident-side linear waveguide 45i, the amount of the portion that has oozed out into the cladding is optical path conversion. It will be lost or crosstalk.

  On the other hand, as in the present embodiment, the width b of the in-plane mirror 5 projected onto the plane orthogonal to the incident-side linear waveguide 45i is larger than the core width a of the incident-side linear waveguide 45i. In other words, the amount of light that has penetrated into the clad and guided into the core temporarily enters the core and is optically converted by the in-plane mirror 5, so that the loss is small.

  There is also another effect. An example of producing a core pattern based on a photolithography method will be described. As shown in FIG. 32A, when the convex mold 30 is formed using a photomask 35 of b ″ = a ″, the photosensitive resin 32 of the convex mold 30 is formed as shown in FIG. Occurs such that b ′ <a ′. This phenomenon is due to the fact that the development easily proceeds at the exposure blur (diffraction of defocus) or at the folded portion.

  Note that b ″ of the photomask 35 is a width obtained by projecting the mask pattern 5 ″ of the in-plane mirror onto the incident-side straight waveguide. A ″ of the photomask 35 is the width of the incident-side straight waveguide 45i ″. Further, b ′ of the photosensitive resin 32 of the convex mold 30 is the projection width of the in-plane mirror equivalent surface 5 ′ located at the waveguide bending portion. The a ′ of the photosensitive resin 32 of the convex mold 30 is the straight waveguide width a ′.

  Now, because of the tendency of b '<a', as shown in FIG. 32C, the projection width b of the in-plane mirror surface 5 of the core 1 is also smaller than the linear waveguide width a.

  Here, as shown in FIGS. 30 and 31, this phenomenon can be eliminated if the pattern of the core of the photomask 35 has a shape b ″> a ″.

  It is preferable to use a photomask having a plurality of linear waveguide patterns and in-plane mirror patterns for forming the core pattern by photolithography.

  The third point of the fourth embodiment relates to the core width of the oblique mirror 4. As shown in FIG. 29, in the case of the waveguide fabrication method in which the core 1 is formed on the first cladding 2, the reflective film 6 is formed on the mirror portions 4 and 5 of the core 1, and then covered with the second cladding 3. The mirror shape of 1 is important. At this time, as shown in FIG. 33, if the core width f of the oblique mirror 4 is made larger than the core width e of the linear waveguide 45, the loss in the oblique mirror 4 can be reduced. As shown in FIG. 34, this may be performed only on the exit side mirror 4o.

  The principle will be described. In the waveguide, most of the light enters the core, but part of the light penetrates into the cladding and is guided. If the core width f of the oblique mirror 4 is equal to the core width e of the straight waveguide 45, the portion that has oozed out into the cladding is not converted into an optical path, resulting in loss or crosstalk. As shown in FIG. 33 (d), if the core width f of the oblique mirror 4 is larger than the core width e of the linear waveguide 45, the amount of light that has penetrated into the clad and has been guided. Since it temporarily enters the core and the optical path is changed by the oblique mirror 4, the loss is small.

  There is also another effect. When the core pattern is formed based on photolithography, as shown in FIG. 35A, the width f ″ of the oblique mirror pattern 4 ″ of the photomask 35 is equal to the width e ″ of the linear waveguide pattern 45 ″. Even if they are equal, as shown in FIGS. 35B to 35C, the projection width f ′ of the oblique mirror equivalent surface 4 ′ of the photosensitive resin 32 of the convex mold 30 is smaller than the linear waveguide width e ′. A phenomenon occurs. Therefore, as shown in FIG. 35 (d), the projection width f of the oblique mirror 4 of the core 1 is also smaller than the straight waveguide width e. This phenomenon is due to exposure blur and the tendency of development to proceed at the edge. However, as shown in FIGS. 33 and 34, if the core width f ″ of the oblique mirror 4 ″ in the photomask 35 is made larger than the core width e ″ of the linear waveguide 45 ″, this phenomenon will occur. Can be countered.

<Example 20>
[process]
Example 20 according to the fourth embodiment will be described with reference to FIG. FIG. 29 shows one core of the optical waveguide as shown in FIG.

  First, a 40 μm-thick dry film resist is bonded onto a substrate 31 (glass), and a photo having a plurality of linear waveguide patterns whose extending directions are orthogonal to each other and in-plane mirror patterns included in these linear waveguides. Exposure and development using a mask.

  As a result, as shown in FIG. 29A, a convex pattern having a linear waveguide equivalent 45 ′ and an in-plane mirror equivalent surface 5 ′ was formed as the photosensitive resin pattern 32.

  Next, by obliquely irradiating laser light, an oblique mirror equivalent surface 4 ′ was produced as shown in FIG.

  And the concave silicone 10 was produced as shown to (c) of FIG. 29 by making the liquid silicone resin 34 overlap and harden | cure on the convex mold 30, and peeling.

  Next, as shown in FIG. 29 (d), a substrate 20 (glass) is prepared, and an epoxy resin layer having a thickness of 30 μm is formed as the clad 2, and then the epoxy resin core 1 is formed using the silicone concave mold 10. Formed.

  Then, as shown in FIG. 29 (e), aluminum was deposited on the mirrors 4 and 5 as a reflective film 6 by mask vapor deposition. As shown in (f) of FIG. 29, an epoxy resin layer is further formed as the second cladding 3, and the waveguide 7 is completed by peeling from the substrate.

<Example 21>
[Waveguide 1]
A waveguide as shown in FIG. 26 was produced by the process of Example 20. When the prototype was produced, the in-plane mirror equivalent surface 5 ′ was formed by photolithography, and the oblique mirror equivalent surface 4 ′ was formed by oblique laser irradiation. Since there are only three types of tilted mirrors, the setting of the sample was completed three times. It was confirmed that infrared light having a wavelength of 0.85 μm was incident from a single mode fiber close to the oblique mirror 4 of the completed waveguide, and that infrared light was emitted from the oblique mirror 4 at the other end. .

<Example 22>
[In-plane mirror 1]
In the process of Example 20, using the photomask 35 shown in FIG. 30A, the in-plane mirror 5 was manufactured as shown in FIGS. 30B to 30C. a is 40 μm and b is 50 μm. Infrared light having a wavelength of 0.85 μm was incident from a single mode fiber close to the waveguide end, and light from the other end was received by a hard polymer clad fiber. By subtracting the loss of the waveguide having the same length from the loss of the waveguide having the in-plane mirror 5, the loss in the in-plane mirror 5 was estimated to be about 1 dB.

<Example 23>
[In-plane mirror 2]
In the process of Example 20, using the photomask 35 shown in FIG. 31A, the in-plane mirror 5 was produced as shown in FIGS. 31B to 31C. a is 40 μm, b is 50 μm, c is 50 μm, and d is 50 μm. Infrared light having a wavelength of 0.85 μm was incident from a single mode fiber close to the waveguide end, and light from the other end was received by a hard polymer clad fiber. By subtracting the loss of the waveguide having the same length from the loss of the waveguide having the in-plane mirror 5, the loss in the in-plane mirror 5 was estimated to be about 1 dB.

<Comparative example 2>
[In-plane mirror 3]
In the process of Example 20, using the photomask 35 shown in FIG. 32A, the in-plane mirror 5 was manufactured as shown in FIGS. 32B to 32C. a was 40 μm and b was 35 μm. Infrared light having a wavelength of 0.85 μm was incident from a single mode fiber close to the waveguide end, and light from the other end was received by a hard polymer clad fiber. By subtracting the loss of the waveguide having the same length from the loss of the waveguide having the in-plane mirror 5, the loss in the in-plane mirror 5 was estimated to be about 2 dB.

<Example 24>
[Slant mirror 1]
In the process of Example 20, using the photomask 35 shown in FIG. 33 (a), the oblique mirror 4 was produced as shown in FIGS. 33 (b) to (d). a is 40 μm and b is 50 μm. Infrared light having a wavelength of 0.85 μm was incident from a single mode fiber close to the end of the waveguide, and light from the oblique mirror 4 at the other end was received by a hard polymer clad fiber. By subtracting the loss of the waveguide of the same length from the loss measured with the oblique mirror 4 as the exit side, the loss at the oblique mirror 4 was estimated to be about 1 dB.

<Comparative Example 3>
[Angle mirror 2]
In the process of Example 20, using the photomask 35 shown in FIG. 35A, the oblique mirror 4 was fabricated as shown in FIGS. a was 40 μm and b was 35 μm. Infrared light having a wavelength of 0.85 μm was incident from a single mode fiber close to the end of the waveguide, and light from the oblique mirror 4 at the other end was received by a hard polymer clad fiber. The loss at the in-plane mirror 4 was estimated to be about 2 dB by subtracting the loss of the waveguide of the same length from the loss measured with the oblique mirror 4 as the exit side.

<Example 25>
[Angle mirror 2]
In the process of Example 20, using the photomask 35 shown in FIG. 34A, the oblique mirror 4 was produced as shown in FIGS. 34B to 34C. a is 40 μm and b is 50 μm. Infrared light having a wavelength of 0.85 μm was incident from a single mode fiber close to the oblique mirror 4, and light from the oblique mirror 4 at the other end was received by a hard polymer clad fiber. Compared to the loss when light is passed in the design direction, the loss in the reverse direction is about 1 dB larger.

  As described above, according to the fourth embodiment and Examples 20 to 25, the following effects can be obtained.

  First, by using an in-plane mirror, the area required for direction change can be reduced. Second, by limiting the direction of the straight waveguide group to several types, the directions of the in-plane mirror and the oblique mirror can be limited (four when the direction is 2), and the processing becomes easy. Third, the loss can be reduced by increasing the width of the in-plane mirror or the oblique mirror.

  Therefore, it is possible to provide an optical waveguide suitable for manufacturing a core connecting a large number of arbitrary points.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described. In the fifth embodiment, when the optical waveguide described in the first to fourth embodiments is bonded to another substrate, the spacer for defining the distance from the other substrate and / or for alignment with the other substrate is used. An alignment table is provided.

  As shown in FIG. 36A, the optical waveguide 7 has a spacer 71 that is higher than the height of the core 1. When this optical waveguide 7 is bonded to another substrate 60 using the clad material 3 ′ as shown in FIG. 36B, the difference (hs) between the height hs of the spacer 71 and the height hc of the core 1 is obtained. -Hc) determines the second cladding 3 thickness. Therefore, the distance from the separate substrate 60 to the core 1 can be precisely controlled. If the substrate 20 is peeled from the optical waveguide 7, a bonded structure can be obtained as shown in FIG.

  The spacer 71 material may be different from the core 1 material, but the process can be simplified if they are the same. For example, a process as shown in FIG. 38 is possible. As shown in FIG. 38 (a), a resist pattern 32 having a core shape is formed on the substrate 31 by photolithography, and as shown in FIG. 38 (b), the resist pattern 32 is formed by oblique irradiation with a laser beam 33. An oblique surface 4 ′ is formed at the end. Next, as shown in FIG. 38C, the convex mold 30 is manufactured by attaching a member 71 'having a predetermined thickness to a portion other than the core. As shown in (d) of FIG. 38, the silicone mold 10 is produced using the mold taking silicone for the convex mold 30. Then, as shown in FIG. 38 (e), the core material 1 'is sandwiched between the separately prepared substrate 20 with the first clad 2 and cured as shown in FIG. 38 (f). As shown in FIG. 38G, when the silicone mold 10 is peeled off, the spacer 71 is also formed at the same time as the core pattern 1. As shown in FIG. 38 (h), a metal 6 is formed on the oblique surface 4 of the core pattern 1 to form a mirror.

  Arbitrary processes, such as (i) mask vapor deposition, (ii) photolithography and etching after metal film formation, or (iii) photolithography, metal film formation, lift-off, etc., can be used for the metal 6 film formation. When the metal 6 is a simple substance or alloy of Al, Au, Pt, Ag, Cu, Ti, a good mirror can be formed.

  Alternatively, for example, a process as shown in FIG. 39 is possible. As shown in FIG. 39A, a first negative type resist layer is formed on the substrate 31, and the core pattern 32 and the spacer pattern 71a 'are exposed. A second negative resist layer is formed, the spacer master 71a 'on the spacer master 71a' is exposed, and the whole is developed. As a result, a spacer pattern 71 ′ that is higher than the height of the core-shaped photosensitive resin 32 by the thickness of the second negative resist layer is formed.

Then, as shown in FIG. 39B, the oblique mirror equivalent surface 4 ′ is formed at the end of the core pattern 32 by oblique irradiation of the laser beam 33, and the convex mold 30 is manufactured. Thereafter, the core 1 and the spacer 71 are formed on the first clad 2 of the substrate 20 as shown in FIGS. 39 (c) to (f) by the same steps as in FIGS. 38 (c) to (g). Form.

  Next, as shown in FIG. 39 (g), a reflective film 6 is formed by depositing a metal on the oblique mirror equivalent surface 4 of the core pattern.

  Further, as shown in FIGS. 37A to 37C, when the clad material 3 ′ is used for bonding to the separate substrate 60, the concave portion 63 and the spacer 71 included in the separate substrate 60 are automatically fitted together. It is possible to obtain a bonded structure that is aligned with each other.

  Further, the fifth embodiment includes an alignment mark 70 for aligning the optical waveguide 7 and the separate substrate 60. As shown in FIG. 40A or 41A, the optical waveguide 7 according to the present embodiment has an alignment mark 70 at the same height as the core 1 or higher. .

  As shown in FIG. 40B or 41B, when the optical waveguide 7 is bonded to another substrate 60, since the distance between the alignment marks 70 and 61 is small, the alignment is performed precisely. be able to. If the substrate 20 is peeled from the optical waveguide 7, a bonded structure as shown in FIG. 40C or 41C can be obtained.

  The alignment mark 70 material may be different from the metal 6 of the mirror part, but if it is the same, the process can be simplified. For example, a process as shown in FIG. 42 is possible. As shown in FIG. 42A, a resist pattern to be the core shape 32 and the alignment mark base 72 'is formed on the substrate 31 by photolithography. The core shape 32 and the alignment mark base 72 'are formed at the same height by the same resist. Thereafter, the core pattern 1 and the alignment mark base 72 are formed in the first step of the substrate 20 as shown in FIGS. 42B to 42F through the same steps as in FIGS. It is formed on the clad 2.

  Next, as shown in FIG. 42G, a mirror and the alignment mark 70 are formed by forming a metal film on the oblique surface 4 of the core pattern 1 and the alignment mark 70 portion of the base 72. Thereafter, as shown in FIG. 42 (h), the core pattern 1, the base 72, and the first cladding 2 may be covered with the second cladding 3. Thus, the optical waveguide 7 is completed on the substrate 20 as shown in FIG.

  Alternatively, for example, a process as shown in FIG. 43 is possible. As shown in FIG. 43A, a first negative type resist layer is formed on the substrate 31, and the core pattern 32 and the alignment mark base 72a 'are exposed. A second negative resist layer is formed, the stage 72b 'on the stage 72a' is exposed, and the whole is developed. As a result, a base 72 ′ that is higher than the height of the core pattern 32 by the thickness of the second negative resist layer is formed.

  Then, as shown in FIG. 43 (b), the oblique mirror equivalent surface 4 ′ is formed at the end of the core pattern 32 by oblique irradiation of the laser beam 33, and the convex mold 30 is manufactured. Thereafter, the core pattern 1 and the alignment mark base 72 are formed on the first substrate 20 as shown in FIGS. 43 (c) to 43 (f) through the same steps as in FIGS. It is formed on the clad 2.

  Next, as shown in FIG. 43 (g), the reflective film 6 and the alignment mark 70 are formed by forming a metal film on the oblique surface 4 and the table 72 of the core pattern. In this case, the alignment mark base 72 can also serve as the spacer 71.

  The formation of the metals 6 and 70 can use the above-described arbitrary steps (i) to (iii). As the metal, when the above-described elemental material alone or an alloy thereof is used, a satisfactory mirror and alignment mark 70 can be formed. The position of the alignment mark 70 is determined based on the position of the core pattern 1 and the position of the mirror 4. Or you may position a metal alignment mark based on another alignment mark (not shown) produced with the core material.

  Moreover, although the optical waveguide with an end mirror has been illustrated so far, an optical waveguide without an end mirror or an optical waveguide with an in-plane mirror may be used.

<Example 26>
[Optical waveguide with spacers]
Example 26 according to the fifth embodiment will be described with reference to FIG. As shown in FIG. 38 (a), a waveguide resist pattern 32 having a cross section of 40 μm square was formed by bonding, exposing, and developing a dry film resist on a substrate 31 (glass).

  Next, as shown in FIG. 38 (b), a laser beam 33 of a KrF excimer laser was obliquely irradiated to form an oblique surface 4 ′ at the end of the resist pattern 32.

  Next, as shown in FIG. 38 (c), a small piece of tape having a thickness of 70 μm was attached to the substrate 31 to form a spacer shape 71 '. Thereby, the convex mold 30 was produced.

Subsequently, a liquid silicone resin was layered on the convex mold 30 and cured at room temperature, followed by peeling, thereby producing the concave mold 10 as shown in FIG. Next, the substrate 20 (glass) was prepared, and an ultraviolet curable epoxy resin was spin-coated as the clad material 2 ′. By irradiating the entire surface with ultraviolet rays of 4 J / cm ² , the clad material 2 ′ was cured to form a 30 μm thick film (not shown).

And as shown to (e)-(f) of FIG. 38, the ultraviolet curable epoxy resin was dripped as the core material 1 'on the concave mold 10, and the board | substrate 20 with the clad 2 was piled up and pressurized. The core material 1 ′ was embedded in the recess of the concave mold 10. In the state shown in FIG. 38 (f), the core material 1 ′ was cured to the core pattern 1 by irradiating with 8 J / cm ² of ultraviolet rays 12 from the substrate 20 side.

  As shown in FIG. 38 (g), the concave mold 10 was peeled off, and as shown in FIG. 38 (h), Al was mask-deposited on the oblique mirror surface 4 of the core pattern 1 as the reflective film 6.

<Example 27>
[Transfer of optical waveguide with spacer]
Example 27 according to the fifth embodiment will be described with reference to FIG. As shown in FIG. 36 (a), an ultraviolet curable epoxy resin is applied to the optical waveguide 7, overlapped with another substrate 60, and irradiated with ultraviolet rays of 4 J / cm ^{2 over} the entire surface from the substrate 20 side. As shown in (b), the second clad 3 / adhesive 62 was cured. As shown in FIG. 36 (c), the substrate 20 was finally peeled off to complete the bonded structure.

<Example 27A>
[Optical Waveguide 2 with Spacer]
Example 27A of the fifth embodiment will be described with reference to FIG. As shown to (a) of FIG. 39, the dry film resist was bonded together on the board | substrate 31 (glass), and the core shape 32 and spacer original pattern 71a 'were exposed. Further, a second dry film resist was bonded to expose the spacer pattern 71a ′. Thereafter, a core shape 32 having a cross section of 40 μm square and a spacer prototype 71 ′ having a height of 70 μm were formed by development.

  Next, as shown in FIG. 39B, a laser beam 33 of a KrF excimer laser was obliquely irradiated to form an oblique mirror equivalent surface 4 ′ on the core-shaped photosensitive resin 32. Thereby, the convex mold 30 was produced.

  A concave mold 10 was produced as shown in FIG. 39 (c) by overlaying a liquid silicone resin on the convex mold 30 and curing it at room temperature, followed by peeling.

Next, the substrate 20 (glass) was prepared, and an ultraviolet curable epoxy resin was spin-coated as the clad material 2 ′. By irradiating the entire surface with ultraviolet rays of 4 J / cm ² , the clad material 2 ′ was cured to form a 30 μm thick film (not shown).

  Then, as shown in (d) to (e) of FIG. 39, an ultraviolet curable epoxy resin was dropped as the core material 1 ′ on the concave mold 10, and the substrate 20 with the clad 2 was stacked and pressed. The core material 1 ′ was embedded in the recess of the concave mold 10.

In the state shown in FIG. 39 (e), the core material 1 ′ was cured on the core 1 and the spacer 71 by irradiating the substrate 20 side with ultraviolet rays of 8 J / cm ² . Next, as shown in FIG. 39 (f), the concave mold 10 is peeled, Al is vapor-deposited on the entire surface, a resist pattern is formed on the surface 4 corresponding to the oblique mirror, phosphoric acid nitric acid etching, and resist removal are performed. As shown in (g) of 39, the reflective film 6 was formed.

<Example 27B>
[Transfer of optical waveguide with spacer 2]
Example 27B according to the fifth embodiment will be described with reference to FIG. As shown in FIG. 37 (a), an ultraviolet curable epoxy resin was applied to the optical waveguide 7, overlapped with another substrate 60 having a recess 63, and the recess 63 and the spacer 71 were fitted together. As a result, alignment was automatically performed. Then, the entire surface of the substrate 20 was irradiated with ⁴ J / cm ² of ultraviolet rays to cure the second clad 3 and adhesive 62 as shown in FIG. As shown in FIG. 37 (c), the substrate 20 was finally peeled off to complete the bonded structure.

<Example 28>
[Optical waveguide with alignment mark]
Example 28 of the fifth embodiment will be described with reference to FIG. As shown in FIG. 42 (a), a dry film resist is bonded onto a substrate 31 (glass), and exposure and development result in a waveguide-shaped resist pattern 32 having a cross section of 40 μm square and an alignment mark trapezoidal shape 72 ′. Formed.

  Next, as shown in FIG. 42 (b), a laser beam 33 of a KrF excimer laser was obliquely irradiated to form an oblique surface 4 ′ at the end of the resist pattern 32. Thereby, the convex mold 30 was produced.

  A concave mold 10 was produced as shown in FIG. 42C by overlapping a liquid silicone resin on the convex mold 30 and curing at room temperature, and peeling the silicone resin from the convex mold 30.

Next, the substrate 20 (glass) was prepared, and an ultraviolet curable epoxy resin was spin-coated as the clad material 2 ′. By irradiating the entire surface with ultraviolet rays of 4 J / cm ² , the clad material 2 ′ was cured to form a 30 μm thick film (not shown).

  Then, similarly to (e) to (g) of FIG. 38 described above, the core pattern 1 and the base 72 are formed on the first cladding 2 of the substrate 20 as shown in (d) to (f) of FIG. did.

Next, Al is vapor-deposited on the entire surface, a resist pattern is formed on the alignment mark base 72 and the oblique mirror surface 4 of the core pattern 1, and phosphoric acid is etched and the resist is removed, as shown in FIG. Then, the alignment mark 70 and the reflective film 6 were formed. An ultraviolet curable epoxy resin was applied to the entire surface and irradiated with ultraviolet rays of 4 J / cm ² , thereby forming the second cladding 3 as shown in FIG.

<Example 29>
[Transfer of optical waveguide with alignment mark]
Example 29 according to the fifth embodiment will be described with reference to FIG. As shown in FIG. 40A, an ultraviolet curable epoxy resin is applied to the optical waveguide 7, overlapped with another substrate 60, aligned using the alignment mark 70, and 4 J / cm ^{2 over the} entire surface from the substrate 20 side. As shown in FIG. 40B, the adhesive 62 was cured by irradiating the ultraviolet rays. Finally, the substrate 20 was peeled off, and the bonded structure was completed as shown in FIG.

<Example 30>
[Optical waveguide with spacer and alignment mark]
Example 30 according to the fifth embodiment will be described with reference to FIG. As shown in FIG. 43 (a), the first dry film resist was bonded onto the substrate 31 (glass), and the core pattern 32 and the alignment mark base pattern 72a ′ (also serving as the spacer pattern) were exposed. Further, a second dry film resist was bonded, and the alignment mark base pattern 72b ′ (also serving as a spacer pattern) was exposed. Thereafter, a core shape 32 having a cross section of 40 μm square and an alignment mark base pattern 72 ′ (also serving as a spacer pattern) having a height of 70 μm were formed by development.

  Next, as shown in FIG. 43 (b), an oblique mirror equivalent surface 4 ′ was formed on the core pattern 32 by obliquely irradiating laser light 33 of a KrF excimer laser. Thereby, the convex mold 30 was produced.

  Next, as shown in FIG. 43 (c), the concave mold 10 was produced by stacking a liquid silicone resin on the convex mold 30 and curing it at room temperature, followed by peeling.

Next, the substrate 20 (glass) was prepared, and an ultraviolet curable epoxy resin was spin-coated as the clad material 2 ′. By irradiating the entire surface with ultraviolet rays of 4 J / cm ² , the clad material 2 ′ was cured to form a 30 μm thick film (not shown).

  Then, as shown in FIGS. 43D to 43E, an ultraviolet curable epoxy resin was dropped on the concave mold 10 as the core material 1 ′, and the substrate 20 with the clad 2 was stacked and pressed. The core material 1 ′ was embedded in the recess of the concave mold 10.

In the state shown in FIG. 43 (e), the core material 1 ′ is cured on the core pattern 1 and the alignment mark base 72 (also serving as the spacer 71) by irradiating the substrate 12 with the ultraviolet rays 12 of 8 J / cm ² . . Next, as shown in FIG. 43 (f), the concave mold 10 is peeled off, Al is vapor-deposited on the entire surface, a resist pattern is formed on the alignment mark position and the oblique mirror surface 4, phosphoric acid nitric acid etching, and resist removal. Thus, as shown in FIG. 43G, the alignment mark 70 and the reflective film 6 were formed.

<Example 31>
[Transfer of optical waveguide with spacer and alignment mark]
Example 31 according to the fifth embodiment will be described with reference to FIG. As shown in FIG. 41 (a), an ultraviolet curable epoxy resin is applied to the optical waveguide 7, overlapped with another substrate 60, aligned using an alignment mark, and 4 J / cm ^{2 on} the entire surface from the substrate 20 side. By irradiating with ultraviolet rays, the second clad 3 and adhesive 62 was cured as shown in FIG. As shown in FIG. 41 (c), the substrate 20 was finally peeled off to complete the bonded structure.

  As described above, according to the fifth embodiment and Examples 26 to 31, the following effects can be obtained.

  First, by using the spacer, the height of the optical waveguide can be precisely controlled, and the process can be simplified by serving as the second cladding and the adhesive layer. Second, the position of the optical waveguide can be precisely controlled by using an alignment mark formed at a height higher than the core height.

  Therefore, the distance between the optical waveguide and another substrate and the accuracy of alignment can be improved, and an optical waveguide suitable for bonding to another substrate can be provided.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide an inexpensive optical waveguide manufacturing method in which the core material is used efficiently and the core is not easily deformed. In addition, it is possible to provide an optical waveguide with good connection efficiency of the optical path conversion mirror, a large element displacement margin, a simple structure, and an inexpensive structure. Furthermore, it is possible to provide an optical waveguide suitable for producing a core connecting many and arbitrary points. In addition, the distance between the optical waveguide and another substrate and the accuracy of alignment can be improved, and an optical waveguide suitable for bonding to another substrate can be provided.

FIG. 1 is a cross-sectional view showing an example of a method of manufacturing an optical waveguide according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view showing a modification of the optical waveguide manufacturing method according to the embodiment. FIG. 3 is a cross-sectional view showing a modification of the optical waveguide manufacturing method according to the embodiment. FIG. 4 is a cross-sectional view and a perspective view showing an example of the concave manufacturing method in the embodiment. FIG. 5 is a perspective view showing an example of an optical waveguide in the embodiment. FIG. 6 is a perspective view showing an example of an optical waveguide in the embodiment. FIG. 7 is a schematic diagram for explaining an angle of a press roll in the embodiment. FIG. 8 is a schematic diagram for explaining an angle of a press roll in the embodiment. FIG. 9A is a perspective view showing an example of a concave shape in the embodiment. FIG. 9B is a perspective view showing an example of a concave shape in the embodiment. FIG. 10 is a cross-sectional view showing a modification of the optical waveguide manufacturing method according to the embodiment. FIG. 11 is a cross-sectional view showing a modification of the method for manufacturing an optical waveguide in the embodiment. FIG. 12 is a cross-sectional view showing an example of a method for manufacturing an optical waveguide according to the second embodiment of the present invention. FIG. 13 is a cross-sectional view showing a modification of the method of manufacturing an optical waveguide in the same embodiment. FIG. 14 is a cross-sectional view showing a modification of the optical waveguide manufacturing method according to the embodiment. FIG. 15 is a cross-sectional view showing a modification of the optical waveguide manufacturing method according to the embodiment. FIG. 16 is a cross-sectional view of a core pattern in the same embodiment. FIG. 17 is an explanatory diagram showing a change in contact angle due to oxygen plasma treatment in the same embodiment. FIG. 18 is a cross-sectional view showing a method for manufacturing an optical waveguide of a comparative example in the embodiment. FIG. 19 is a cross-sectional view schematically showing an optical waveguide according to the third embodiment of the present invention. FIG. 20 is a cross-sectional view schematically showing an optical waveguide according to the third embodiment of the present invention. FIG. 21 is a cross-sectional view showing an example of a method for manufacturing an optical waveguide in the embodiment. FIG. 22 is a perspective view showing each example of a method for forming a convex surface in the embodiment. FIG. 23 is a perspective view showing each example of a method for forming a convex surface in the embodiment. FIG. 24 is a perspective view showing each example of a method for forming a convex surface in the embodiment. FIG. 25 is a perspective view showing each example of a method for forming a convex surface in the embodiment. FIG. 26 is a perspective view showing an example of an optical waveguide according to the fourth embodiment of the present invention. FIG. 27A is an explanatory diagram showing types of in-plane mirrors and oblique mirrors in the embodiment. FIG. 27B is an explanatory diagram showing types of in-plane mirrors and oblique mirrors in the embodiment. FIG. 28A is an explanatory diagram showing types of in-plane mirrors and oblique mirrors in the embodiment. FIG. 28B is an explanatory diagram showing types of in-plane mirrors and oblique mirrors in the embodiment. FIG. 29 is an explanatory diagram illustrating an example of a method of manufacturing an optical waveguide according to the embodiment. FIG. 30 is a perspective view showing an example of an in-plane mirror shape and a method for forming the same in the embodiment. FIG. 31 is a perspective view showing an example of an in-plane mirror shape and a method for forming the same in the embodiment. FIG. 32 is a perspective view showing an example of a normal in-plane mirror shape and a method for forming the same. FIG. 33 is a perspective view showing an example of an oblique mirror shape and a method for forming the same in the embodiment. FIG. 34 is a perspective view showing an example of an oblique mirror shape and a method for forming the same in the embodiment. FIG. 35 is a perspective view showing an example of a normal oblique mirror shape and a method for forming the same. FIG. 36 is a cross-sectional view showing an example of a method of manufacturing an optical waveguide according to the fifth embodiment of the present invention. FIG. 37 is a cross-sectional view showing an example of an optical waveguide manufacturing method according to the fifth embodiment of the present invention. FIG. 38 is a cross-sectional view showing an example of a method of manufacturing an optical waveguide according to the fifth embodiment of the present invention. FIG. 39 is a cross-sectional view showing an example of an optical waveguide manufacturing method according to the fifth embodiment of the present invention. FIG. 40 is a cross-sectional view showing an example of a method for manufacturing an optical waveguide according to the fifth embodiment of the present invention. FIG. 41 is a cross-sectional view showing an example of a method of manufacturing an optical waveguide according to the fifth embodiment of the present invention. FIG. 42 is a cross-sectional view showing an example of a method for manufacturing an optical waveguide according to the fifth embodiment of the present invention. FIG. 43 is a cross-sectional view showing an example of a method of manufacturing an optical waveguide according to the fifth embodiment of the present invention. FIG. 44 is a cross-sectional view showing an example of a conventional method for manufacturing an optical waveguide. FIG. 45 is a cross-sectional view showing another example of a conventional method for manufacturing an optical waveguide. FIG. 46 is a cross-sectional view showing an example of a conventional mirror manufacturing method. FIG. 47 is a sectional view schematically showing a conventional optical waveguide. FIG. 48 is a perspective view showing an example of a conventional optical waveguide. FIG. 49 is a cross-sectional view showing an example of a conventional method for manufacturing an optical waveguide.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Core pattern, 1 '... Core material, 2 ... 1st clad, 3 ... 2nd clad, 10 ... Concave type, 11 ... Press roll, 20 ... Substrate.

Claims (28)

An optical waveguide manufacturing method comprising a core and a cladding,
Applying and curing a resin on the substrate (20) to form the first cladding (2);
Sandwiching a core material (1 ′) between a concave mold (10) having a recess in the core pattern shape and having a backing material (15) on the back surface and a first cladding on the substrate;
Curing the sandwiched core material to form a core pattern (1) corresponding to the depression on the first cladding;
Peeling the concave mold (10) from the core pattern and the first cladding;
A method for manufacturing an optical waveguide, comprising: In the manufacturing method of the optical waveguide according to claim 1,
The method of manufacturing an optical waveguide, wherein the backing material is an inorganic material. In the manufacturing method of the optical waveguide according to claim 1,
A method of manufacturing an optical waveguide, wherein a thermal expansion coefficient of the backing material and a thermal expansion coefficient of a substrate on which the first cladding is formed coincide with each other. In the manufacturing method of the optical waveguide according to claim 1,
The method of manufacturing an optical waveguide, wherein the step of curing the sandwiched core material (1 ′) includes an ultraviolet curing step of irradiating the core material with ultraviolet rays through the substrate and the first cladding. In the manufacturing method of the optical waveguide according to claim 1,
The method of manufacturing an optical waveguide, wherein a press roll (11) is used in the step of sandwiching the core material (1 ′). In the manufacturing method of the optical waveguide according to claim 5,
An optical waveguide manufacturing method, wherein an angle formed between a substrate moving direction of the press roll and a main straight line portion of the concave depression is approximately 45 ° or less. In the manufacturing method of the optical waveguide according to claim 1,
Applying and curing a resin so as to cover the core pattern (1) and the first cladding (2) to form a second cladding (3);
An optical waveguide manufacturing method, further comprising: In the manufacturing method of the optical waveguide according to claim 1,
A method of manufacturing an optical waveguide, further comprising a step of removing a thin core remaining on the surface of the first cladding after the step of peeling the concave mold (10) is completed. In the manufacturing method of the optical waveguide according to claim 8,
The method of manufacturing an optical waveguide, wherein the step of removing the thin remaining core uses an oxygen plasma treatment. In the manufacturing method of the optical waveguide according to claim 1,
The concave mold (10) has an inclined mirror-equivalent surface whose end of the depression is approximately 45 °,
The said core pattern (1) has the edge part to which the said diagonal mirror equivalent surface was transcribe | transferred, The manufacturing method of the optical waveguide characterized by the above-mentioned. In the manufacturing method of the optical waveguide according to claim 10,
Prior to the step of sandwiching the core material (1 ′), a step of forming a reflective film in advance on the mirror equivalent surface of the concave mold (10),
The method of manufacturing an optical waveguide, wherein the step of peeling the concave mold (10) includes a step of transferring the reflective film to an end portion of the core pattern. In the manufacturing method of the optical waveguide according to claim 1,
The recess in the concave mold (10) includes two linear portions formed so that one ends thereof are connected at right angles to each other, and an in-plane mirror equivalent surface for optically connecting these linear portions,
The said core pattern (1) is a manufacturing method of the optical waveguide characterized by transferring each said linear part and the said surface equivalent to an in-plane mirror. In the manufacturing method of the optical waveguide according to claim 1,
The method of manufacturing an optical waveguide, wherein the concave mold (10) has a concave curved end portion. In the manufacturing method of the optical waveguide according to claim 1,
The recess in the concave mold (10) has a spacer shape that is formed deeper than the depth of the core pattern shape separately from the core pattern shape. In the manufacturing method of the optical waveguide according to claim 1,
The recess in the concave mold (10) has a base member shape formed at a depth equal to or greater than the depth of the core pattern shape separately from the core pattern shape. In the manufacturing method of the optical waveguide according to claim 1,
The concave mold (10) is a method for producing an optical waveguide, wherein at least a surface material is a silicone resin or a fluororesin. In the manufacturing method of the optical waveguide according to claim 1,
Before the step of sandwiching the core material (1 ′), the method further comprises a step of subjecting the concave mold (10) to a surface treatment for increasing the affinity with the core material (1 ′) in advance. An optical waveguide manufacturing method. In the manufacturing method of the optical waveguide according to claim 17,
The method for manufacturing an optical waveguide, wherein the surface treatment is an oxygen plasma treatment. In the manufacturing method of the optical waveguide according to claim 17,
The method for manufacturing an optical waveguide, wherein the surface treatment is a treatment for reducing a contact angle of the core material (1 ′) to the concave mold (10) to 45 ° or less. In the manufacturing method of the optical waveguide according to claim 1,
Forming a convex pattern (30) by forming a core pattern-shaped convex section (32) on the substrate (31);
Applying and curing a resin to the convex mold, peeling the convex mold from the resin to produce a concave mold (10);
An optical waveguide manufacturing method, further comprising: In the manufacturing method of the optical waveguide according to claim 20,
The convex portion in the convex mold (30) is
Two straight portions formed so that one ends thereof are connected at right angles to each other;
An in-plane mirror equivalent surface for optically connecting these linear portions;
A method for manufacturing an optical waveguide, comprising: In the manufacturing method of the optical waveguide according to claim 21,
A method of manufacturing an optical waveguide, wherein the convex equivalent surface mirror is formed by laser processing. In the manufacturing method of the optical waveguide according to claim 21,
The convex portion has an end portion having a surface corresponding to an oblique mirror. In the manufacturing method of the optical waveguide according to claim 23,
The method of manufacturing an optical waveguide, wherein the surface corresponding to the oblique mirror of the convex portion is formed into a sloped convex curved surface. In the manufacturing method of the optical waveguide according to claim 23,
A method of manufacturing an optical waveguide, wherein the convex oblique mirror equivalent surface is formed by laser processing. In the manufacturing method of the optical waveguide according to claim 24,
The step of producing the convex mold (30) includes:
Forming a convex portion formed of a resist pattern having a core pattern shape on the substrate (31) by photolithography;
The step of forming the sloped convex curved surface by obliquely irradiating the end of the convex with a laser beam having a substantially circular shadow and partially evaporating the end;
An optical waveguide manufacturing method, further comprising: In the manufacturing method of the optical waveguide according to claim 24,
The step of producing the convex mold (30) includes:
Forming a convex portion formed of a resist pattern having a core pattern shape on the substrate (31) by photolithography;
Irradiating laser light multiple times from different directions to the end of the convex part, and partially evaporating the end part, thereby forming the sloped convex curved surface;
An optical waveguide manufacturing method, further comprising: In the manufacturing method of the optical waveguide according to claim 24,
The step of producing the convex mold (30) includes:
Forming a convex portion formed of a resist pattern having a core pattern shape on the substrate (31) by photolithography;
Irradiating laser light obliquely to the end of the convex part and partially evaporating the end part, thereby forming the end part into a sloped shape; and
After the laser light irradiation, the step of forming the sloped convex curved surface by increasing the temperature and flowing the resist;
An optical waveguide manufacturing method, further comprising:

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