JP2015025953A - Optical fiber connector, manufacturing method therefor, and optical fiber cable with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide; an optical fiber connector which offers reduced variation in thickness of a plurality of optical transmission core patterns, a minor difference between a height of an optical waveguide up to an upper cladding layer surface and a height of an optical fiber guide section, and reduced variation in optical coupling loss with optical fibers; a manufacturing method therefor; and an optical fiber cable with the same; as well as a manufacturing method for the optical fiber connector, which suppresses generation of air bubbles during the manufacturing process.SOLUTION: An optical fiber connector comprises an optical waveguide section having lower cladding layers 3, a plurality of optical transmission core patterns 7, and an upper cladding layer, and an optical fiber guide section having optical fiber mounting grooves for fixing optical fibers, which are located side-by-side on a substrate 1. The optical waveguide section has at least one lower cladding groove 5 formed at one location between the plurality of optical transmission core patterns 7. The optical fiber guide section has the optical fiber mounting grooves arranged such that optical fibers fixed thereto are coupled with the optical transmission core patterns 7 in a way that enables optical signal transmission.

Description

  The present invention relates to an optical fiber connector and a manufacturing method thereof, in particular, a thickness variation of a plurality of core patterns for light transmission, and a difference between the height to the surface of the upper clad layer of the optical waveguide and the height of the optical fiber guide portion is small The present invention relates to an optical fiber connector capable of reducing variations in coupling loss with an optical fiber, a manufacturing method thereof, and an optical fiber cable in which an optical fiber is mounted on the optical fiber connector. Furthermore, it is related with the manufacturing method of the optical fiber connector which can suppress generation | occurrence | production of the bubble in a manufacturing process.

In general, optical fibers are widely used for home and industrial information communication because they can perform high-speed communication of a large amount of information. For example, automobiles are equipped with various electrical components (for example, a car navigation system), and are also used for optical communication of these electrical components. As an optical cable connector for connecting the ends of optical fibers included in such an optical cable, there is one disclosed in Patent Document 1.
In addition, with the increase in information capacity, development of optical interconnection technology using optical signals not only for communication fields such as trunk lines and access systems but also for information processing in routers and servers is underway. Specifically, since light is used for short-distance signal transmission between boards in a router or server device, the optical transmission path has a higher degree of freedom of wiring and higher density than optical fibers. Possible optical waveguides are used.
And when joining this optical waveguide and an optical fiber, an optical fiber connector as described in patent document 2 is mentioned, for example.
However, in such an optical fiber connector, since the optical fiber mounting groove needs to be cut by dicing, the work efficiency is poor, and the optical waveguide core is formed by photolithography and etching in a process different from the groove cutting process. Due to the production, the optical fiber may be misaligned. Further, in the above-described method, if the substrate is not formed on a hard substrate having good dimensional stability such as a silicon wafer, a larger positional shift of the optical fiber occurs.
Also, an optical waveguide substrate on which an optical waveguide described in Patent Document 3 is formed and an optical connector in which an optical fiber is carried are attached to different holders, and the optical fibers and optical fibers that fix the end faces of each holder are fixed. There is a method for connecting waveguides, but the number of steps until connection is large and complicated.
As a method for solving them, there is an optical fiber connector in which a side wall of an optical fiber mounting groove and a core pattern for light transmission are formed in the same process as described in Patent Document 4.

JP 2010-48925 JP 2001-201646 A Japanese Patent Laid-Open No. 7-13040 JP 2009-198803 A

However, in the thing of patent document 4, since the several core pattern for light transmission is formed on the lower clad layer which is one pattern, when resin for core pattern formation is laminated | stacked, each core for light transmission Since the resin flow (fluidity) of the pattern varies depending on the location, there is a concern that the height of the core pattern may vary. This causes variations in coupling loss between the optical fiber and the optical waveguide. The same applies to the upper clad layer after the core pattern is formed, and there is a concern that the height from the substrate surface to the upper clad layer provided on the optical fiber guide part and the height from the upper clad layer of the optical waveguide may vary. . As a result, the optical fiber cannot be pressed well against the optical fiber mounting groove, resulting in variations in coupling loss. The optical fiber mounting groove is a layer lower than the surface of the lower clad layer, and when forming the core pattern forming resin layer and the upper clad layer forming resin layer during manufacture, bubbles are formed near the optical fiber mounting groove. Occurs and it is difficult to form a good pattern.
In addition, in the description of Patent Document 4, the adhesive introduction groove is formed simultaneously with the core pattern. However, if the optical fiber is connected to the end face of the optical waveguide, the optical fiber becomes a wall that hinders the flow of the adhesive, which is good. There is also a concern that the adhesive does not flow and the connection is poor.
The present invention has been made in order to solve the above-described problems, and there is little variation in the thickness of a plurality of core patterns for light transmission, and the difference between the height to the surface of the upper cladding layer of the optical waveguide and the height of the optical fiber guide portion. The present invention provides an optical fiber connector that can reduce variations in coupling loss with an optical fiber, a method for manufacturing the same, and an optical fiber cable in which the optical fiber is mounted on the optical fiber connector. The present invention provides a method for manufacturing an optical fiber connector capable of suppressing the occurrence of the above.

The present invention provides the following inventions.
(1) An optical waveguide portion having a lower clad layer, a plurality of light transmission core patterns and an upper clad layer, and an optical fiber guide portion having an optical fiber mounting groove for fixing the optical fiber are provided on the substrate. In the optical fiber connector, the optical waveguide portion has a lower clad groove formed at least at one position between a plurality of optical transmission core patterns, and the optical fiber guide portion includes the optical fiber to be fixed and the optical transmission portion. An optical fiber connector in which the fiber mounting groove is arranged so that the core pattern is bonded to a position where an optical signal can be transmitted.
(2) The optical fiber connector according to (1), wherein the lower clad groove is formed so as to divide the lower clad layer at least at one position between a plurality of optical transmission core patterns.
(3) The optical fiber connector according to (1) or (2), wherein the lower cladding groove and the core pattern for light transmission extend in a substantially parallel direction.
(4) The optical fiber connector according to any one of (1) to (3), wherein a bottom surface of the optical fiber mounting groove and a bottom surface of the lower cladding groove are on the same plane.
(5) The optical fiber connector according to any one of (1) to (4), wherein variation in height of the plurality of optical transmission core patterns is ± 5 μm or less.
(6) The optical fiber connector according to any one of (1) to (5), wherein a difference between a height from the substrate surface to the upper surface of the optical waveguide and a height from the upper surface of the optical fiber guide portion is 10 μm or less.
(7) An optical waveguide portion having a lower clad layer, a plurality of light transmission core patterns, an upper clad layer, and an optical fiber guide portion having an optical fiber mounting groove for fixing the optical fiber are provided on the substrate. An optical fiber connector manufacturing method comprising:
Forming a resin layer for forming a lower clad layer on a substrate, and forming, by etching, a lower clad layer removing portion including an optical fiber mounting groove in the optical fiber guide portion and a lower clad groove in the optical waveguide portion;
A resin layer for forming a core pattern is formed from the lower clad layer forming surface side, and an optical transmission core pattern on the lower clad layer in the optical waveguide portion and light on the lower clad layer in the optical fiber guide portion are etched. Forming a side wall of the fiber mounting groove; and forming an upper cladding layer forming resin layer from the light transmitting core pattern forming surface side and etching the upper cladding layer on the optical fiber mounting groove in the optical fiber guide portion The manufacturing method of the optical fiber connector which has the process C which removes.
(8) The optical fiber connector according to (7), wherein in the step A, the lower cladding layer removing portion including the optical fiber mounting groove in the optical fiber guide portion and the lower cladding groove in the optical waveguide portion are connected to each other. Production method.
(9) The method of manufacturing an optical fiber connector according to (7) or (8), wherein an optical path conversion mirror is formed on an optical axis of a core pattern for light transmission in the optical waveguide portion,
(10) Any of (7) to (9), wherein at least one of the lower clad layer forming resin layer, the core pattern forming resin layer, and the upper clad layer forming resin layer is a photosensitive resin layer. The manufacturing method of the optical fiber connector of description.
(11) At least one of the lower clad layer forming resin layer, the core pattern forming resin layer, and the upper clad layer forming resin layer is a dry film according to any one of (7) to (10). Manufacturing method of optical fiber connector.
(12) A substrate groove is formed on the substrate so as to sandwich the core pattern for light transmission and the optical fiber mounting groove forming portion, or a substrate groove at an end of the optical fiber mounting groove forming portion on the optical waveguide side The optical fiber connector manufacturing method according to any one of (7) to (11), further including step D, wherein step D is performed before step B or step C.
(13) An optical fiber connector obtained by the method for manufacturing an optical fiber connector according to any one of (7) to (12).
(14) An optical fiber cable in which an optical fiber is mounted in the optical fiber mounting groove of the optical fiber connector according to any one of (1) to (6) and (13).

  The optical fiber connector of the present invention, the manufacturing method thereof, and the optical fiber cable obtained thereby can reduce variations in the thickness of a plurality of core patterns for light transmission, and the height to the surface of the upper cladding layer of the optical waveguide and the optical fiber guide There is little difference with the height of the part, and variation in coupling loss with the optical fiber can be reduced. Furthermore, in the manufacturing method of the optical fiber connector of this invention, generation | occurrence | production of the bubble in a manufacturing process can be suppressed.

It is a top view which shows an example of the manufacturing method of the optical fiber connector of this invention, and the manufacturing method is shown in order from (a) to (f) (shown (a)-(c)). It is a top view which shows an example of the manufacturing method of the optical fiber connector of this invention, and the manufacturing method is shown in order from (a) to (f) (it shows (d)-(f)). It is optical fiber mounting groove | channel perpendicular | vertical A-A 'sectional drawing which shows an example of the optical fiber connector of this invention. It is a core pattern vertical direction B-B 'cross section for optical transmission of an optical waveguide showing an example of an optical fiber connector of the present invention. It is a core pattern coaxial direction C'-C sectional view for optical transmission of an optical waveguide showing an example of an optical fiber connector of the present invention. It is optical fiber mounting groove coaxial direction D'-D sectional drawing which shows an example of the optical fiber connector of this invention.

  The optical fiber connector of the present invention will be described with reference to FIGS. An optical fiber connector according to the present invention is mounted on an optical fiber for fixing an optical fiber 14 and an optical waveguide portion 12 having a lower cladding layer 3, a plurality of optical transmission core patterns 7, and an upper cladding layer 9 on a substrate 1. This is an optical fiber connector provided with an optical fiber guide portion having a groove 11. In the optical waveguide portion 12, the lower cladding groove 5 is formed in the lower cladding layer 3 at least at one place among the plurality of core patterns 7 for light transmission, preferably every two to three core patterns. Optical fiber connector. Further, the optical fiber guide portion is arranged with the optical fiber mounting groove 11 so that the optical fiber 14 to be fixed is joined to the optical transmission core pattern 7 of the optical waveguide portion 12 at a position where the optical signal can be transmitted. The structure is as follows.

By forming the lower cladding groove 5, it is possible to obtain a groove that can suppress the warping of the pattern of the lower cladding layer 3. It is preferable that the lower cladding layer 3 is partly or partially divided by the lower cladding groove 5 by the lower cladding groove 5. The division means that a portion where the lower cladding layer does not exist is formed by forming the lower cladding groove (the sectional view of FIG. 3 is in this state). That all are divided means that the lower clad layer is completely divided into a plurality of lower clad layer patterns by the lower clad groove. By dividing the lower clad layer in this way, the contraction of the lower clad layer 3 is also divided into each pattern, and the warpage of the optical fiber connector can be suppressed. This effect has the advantage of improving the handling properties during the process.
Further, when the core pattern and the resin layer for forming the upper clad layer are formed and then the optical transmission core pattern 7, the optical fiber guide core 8, and the upper clad layers 9 and 10 are formed by etching, the lower clad groove 5 is formed. As a result, when the resin layer for forming the core pattern and the resin layer for forming the upper cladding layer are formed, the flow of the resin to the lower cladding groove 5 occurs, and the fluidity of the resin on the entire substrate 1 is improved. Even if the optical transmission core pattern 7 is formed, it is possible to make the thickness of the optical transmission core pattern 7 uniform, and it is possible to send and receive a good optical signal to and from the optical fiber 14. In the present invention, it is preferable to suppress the variation of the core pattern for light transmission to ± 5 μm or less, and this is possible. This effect is the same when the upper cladding layers 9 and 10 are formed, and the difference between the height from the surface of the substrate 1 to the upper surface of the optical waveguide portion 12 and the upper surface of the optical fiber guide portion can be suppressed to 10 μm or less. Thus, when the optical fiber 14 is mounted in the optical fiber mounting groove 11, the inclination of the glass block can be reduced even if it is suppressed by a glass block or the like so as to straddle the optical waveguide and the optical fiber guide portion. Good alignment with the core pattern 7 for light transmission can be achieved.
If the lower clad groove 5 is not formed, the lower clad layer removal portion 6 including the optical fiber mounting groove (also referred to as the removal portion 6 when the lower clad layer is not formed in advance) becomes a concave portion, and the core pattern forming resin layer When forming the upper cladding layer forming resin layer, bubbles are likely to be generated. When bubbles are generated, it becomes difficult to form a well-shaped optical fiber guide core and the upper clad layer 10 thereon.

The optical fiber connector of the present invention preferably has a substrate groove 2 between the optical waveguide portion 12 and the optical fiber guide portion as shown in FIGS. It is preferable that both portions are sandwiched. From a structural point of view, the formed light transmission core pattern 7 and the optical fiber mounting groove forming portion (the lower clad layer removing portion including the optical fiber mounting groove) 6) or at the end of the optical fiber mounting groove forming portion (the lower clad layer removing portion 6 including the optical fiber mounting groove) on the optical waveguide side. preferable. By having the substrate groove 2, when the optical fiber 14 is bonded using an adhesive or the like, it functions as a groove through which the adhesive flows, and the mounting time of the optical fiber 14 can be shortened. Even after the optical fiber 14 is abutted against the optical waveguide portion 12, the liquid around the adhesive is good.
In addition, when the core pattern 7 and the upper cladding layer forming resin layer are formed and then the optical transmission core pattern 7, the optical fiber guide core 8, and the upper cladding layers 9 and 10 are formed by etching, the substrate groove 2 is formed in advance. Therefore, when the resin layer is formed as described above, bubbles are generated in the lower cladding layer removing portion 6 including the optical fiber mounting groove. However, since the bubbles can be discharged through the substrate groove 2, the resin layer is laminated with a high yield. And an optical fiber guide portion having a good shape can be formed.

In the present invention, the optical fiber guide portion represents a portion having a member forming the side surface of the optical fiber mounting groove 11, and the optical fiber mounting groove 11 is made of the same material as the optical transmission core pattern 7. The optical fiber guide core 8 may include a dummy lower cladding layer 4 formed of the same material as the lower cladding layer and an upper cladding layer 10. When the upper clad layer 10 is provided in at least one optical fiber guide core 8, it is easy to match the height (maximum height) of the surface of the upper clad layer 9 of the optical waveguide, and when the optical fiber 14 is mounted in the optical fiber mounting groove 11. The optical fiber 14 can be pressed (suppressed) well.
In the present invention, the optical fiber guide core 8 is for fixing the optical fiber 14 and does not function as a core for light transmission.
Further, although there is no limitation on the optical fiber to be used, when it is expressed as “optical fiber diameter” below, it represents the cladding outer diameter of the optical fiber or the coating outer diameter of the optical fiber.

  In the optical fiber connector of the present invention, the lower clad groove 5 and the light transmission core pattern 7 described above preferably extend in a substantially parallel direction. Here, the substantially parallel direction means that the portion of the light transmitting core pattern 7 where light propagates and the lower cladding groove 5 do not cross each other, and meandering even when the lower cladding groove 5 is divided. Even in this case, the direction is almost parallel. If the optical transmission core pattern 7 and the lower cladding groove 5 do not intersect, the thickness of the optical transmission core pattern 7 is substantially constant, so that an optical signal can be propagated satisfactorily.

In the optical fiber connector of the present invention, the bottom surface of the optical fiber mounting groove 11 and the bottom surface of the lower cladding groove are preferably flush with each other. If they are on the same plane, the warpage of the substrate 1 can be reduced.
Furthermore, when the core pattern forming resin layer and the upper clad layer forming resin layer are formed, the generation of bubbles can be further reduced. The same plane may be the surface of the substrate.
Hereinafter, each member of the optical fiber connector of the present invention will be described in detail.

[substrate]
The material of the substrate is not particularly limited, and examples thereof include a glass epoxy resin substrate, a ceramic substrate, a glass substrate, a silicon substrate, a plastic substrate, a metal substrate, a substrate with a resin layer, a substrate with a metal layer, a resin film, and an electric wiring board. Is mentioned. As resin films, polyesters such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate, polyolefins such as polyethylene and polypropylene, polyamide, polycarbonate, polyphenylene ether, polyether sulfide, polyarylate, liquid crystal polymer, polysulfone, polyethersulfone and polyether Ether ketone, polyether imide, polyamide imide, polyimide and the like are preferable.
The thickness of the substrate is not particularly limited, but the thickness of the substrate is preferably 5 μm to 1 mm, more preferably 10 to 100 μm, from the viewpoint of securing strength and reducing optical loss due to shortening of the optical path.
When the optical signal is transmitted through the substrate 1, the substrate 1 that can transmit the optical signal to be used may be used. For example, when the optical signal to be used is infrared light, the resin substrate that transmits infrared light A silicon substrate or the like may be used. In the case of the substrate 1 that does not transmit an optical signal, it is preferable to provide an opening in a portion that transmits the optical signal.
If the substrate 1, the lower cladding layer 3, and the optical fiber guide core 8 have no or weak adhesive force, the substrate 1 with an adhesive layer may be used.

[Substrate groove]
The optical transmission core pattern 7 and the optical fiber mounting groove forming part (the lower cladding layer removing part 6 including the optical fiber mounting groove) are sandwiched, or the optical fiber mounting groove forming part (the lower part including the optical fiber mounting groove). The substrate groove 2 is preferably provided at the end of the cladding layer removing portion 6) on the optical waveguide portion 12 side. The substrate groove 2 may be a substrate in which a groove is formed directly on the substrate 1 or a substrate 1 formed by forming a grooved resin layer on the substrate. When the optical transmission core pattern 7 and the optical fiber mounting groove forming portion (the lower cladding layer removing portion 6 including the optical fiber mounting groove) are formed to be sandwiched, the optical transmission core pattern 7 is patterned by etching. In addition, even if skirting due to insufficient development or residual development occurs in the skirt, the skirting can be made in the substrate groove 2, so that the end face of the optical waveguide is flattened using a dicing saw or the like in a later step. Even if it is not necessary, the optical fiber 14 and the optical waveguide can be bonded satisfactorily.
As a method of directly forming the groove, for example, a method of forming the substrate groove 2 by deforming the substrate 1 using press or injection molding, a method of providing the substrate groove 2 on the substrate 1 using dicing or laser ablation, or the like. Is mentioned.
As a method for forming a resin layer with a groove on the substrate to form the substrate 1, for example, a photosensitive resin layer is formed on the substrate, and the resin in the substrate groove 2 is removed by photolithography and formed. it can. The formation of the substrate groove 2 by photolithography is preferred from the viewpoint that collective processing generates less foreign matter such as cutting scraps.
Even after the optical waveguide portion 12 and the optical fiber mounting groove 11 are formed, the substrate groove 2 sandwiches the end portion of the optical waveguide or is formed at the end portion of the optical fiber mounting groove 11 on the optical waveguide portion 12 side. It should be exposed. The term “end portion” as used herein generally means that the distance from the end face of the optical waveguide section 12 to the beginning of the recess of the substrate groove 2 is 0 μm. In the present invention, the end face of the optical waveguide section 12 of the optical fiber mounting groove 11 is used. The end and the vicinity of the end within 0 to 200 μm are defined as ends in a broad sense. Further, the width of the substrate groove 2 (width in the optical axis direction) may be in a range where the tip of the optical fiber 14 is bent and cannot be satisfactorily connected to the optical waveguide, and is preferably 5 to 300 μm. More preferably, it is 25-200 micrometers, More preferably, it is 50-150 micrometers. In other words, the substrate groove 2 is preferably formed within 5 to 500 μm from the optical waveguide. By forming the substrate groove 2 at the end on the optical waveguide portion 12 side, the adhesive can be efficiently filled when the optical waveguide portion 12 and the optical fiber 14 are bonded.
The depth of the substrate groove 2 may be appropriately selected depending on the thickness and strength of the substrate 1 and the fluidity of the adhesive, and is preferably 5 to 50 μm, more preferably 5 to 30 μm, and more preferably 5 to 25 μm. More preferably it is.

[Lower cladding layer / Upper cladding layer]
Hereinafter, the lower clad layer 3, the dummy lower clad layer 4, and the upper clad layers 9 and 10 used in the present invention will be described. As the lower clad layer 3, the dummy lower clad layer 4, and the upper clad layers 9 and 10, a clad layer forming resin or a clad layer forming resin film can be used.

  The resin for forming the clad layer used in the present invention is not particularly limited as long as it is a resin composition that has a lower refractive index than that of the light transmitting core pattern 7 and is cured by light or heat, and is not limited. A resin composition can be suitably used. The resin composition used for the resin for forming the cladding layer may be the same or different in the components contained in the resin composition in the lower cladding layer 3, the dummy lower cladding layer 4, and the upper cladding layers 9 and 10. The refractive index of the resin composition may be the same or different.

  The dummy lower clad layer 4 is not limited in refractive index or the like, but if it is formed at the same time as the lower clad layer 3, it is preferable from the viewpoint of positional accuracy. Therefore, the dummy lower clad layer 4 is preferably a resin composition similar to the lower clad layer 3. In addition, the dummy lower cladding layer 4 may not be disposed. However, when the dummy lower cladding layer 4 is disposed, the pattern area of the lower cladding layer with the lower cladding layer 3 (optical waveguide portion) can be made the same or close, and the core pattern forming resin or Since the flatness of the resin for forming the upper clad layer is more easily secured, it is preferably provided.

In the present invention, the method for forming the clad layer is not particularly limited. For example, the clad layer may be formed by applying a clad layer forming resin or laminating a clad layer forming resin layer (dry film).
In the case of application, the method is not limited, and the clad layer forming resin composition may be applied by a conventional method.
The clad layer-forming resin layer (dry film) used for laminating can be easily manufactured by, for example, dissolving the clad layer-forming resin composition in a solvent, applying it to a support film, and removing the solvent. Can do.

The thicknesses of the lower cladding layer 3, the dummy lower cladding layer 4, and the upper cladding layers 9 and 10 are not particularly limited, but the thickness after drying is preferably in the range of 5 to 500 μm. When the thickness is 5 μm or more, a clad thickness necessary for light confinement can be secured, and when the thickness is 500 μm or less, it is easy to control the film thickness uniformly. From the above viewpoint, the thickness of the lower cladding layer 3 and the upper cladding layers 9 and 10 is more preferably in the range of 10 to 200 μm. Further, the lower clad layer 3 has a cured film thickness of {(radius of the optical fiber) − (light transmission formed on the lower clad layer 3) in order to align the center of the optical fiber and the center pattern of the light transmission core. It is more preferable to use a film having a thickness of core pattern thickness) / 2}. When a gap is formed between the optical fiber mounting groove 11 and the optical fiber 14 when the optical fiber 14 is fixed with an adhesive or the like, a film having a thickness obtained by adding the thickness of the gap to the above value is further used. Good.
A specific example shows a preferable thickness of the lower cladding layer 3 when an optical fiber having an optical fiber diameter of 80 μm and an optical fiber core diameter of 50 μm is used. First, when the optical signal propagates from the optical fiber to the optical transmission core pattern, a square circumscribing the core diameter of the optical fiber can propagate without optical loss. In this case, the core of the optical waveguide is 50 μm × 50 μm (core height: 50 μm). Applying the above formula, the optimum thickness of the lower cladding layer 3 is 15 μm (= 40-50 / 2). In addition, when an optical signal is propagated from the optical fiber to the optical transmission core pattern using the same optical fiber as described above, a square inscribed in the core diameter of the optical fiber can propagate without optical loss. In this case, the core of the optical waveguide is 36 μm × 36 μm (core height: 36 μm). Applying the above formula, the optimum thickness of the lower cladding layer 3 is 22 μm (= 40−36 / 2). When a gap is formed between the optical fiber mounting groove 11 and the optical fiber 14, it is better to use a film having a thickness obtained by adding the thickness of the gap to the above value.
In the optical waveguide, the thickness of the upper cladding layers 9 and 10 for embedding the light transmission core pattern 7 is preferably equal to or greater than the thickness of the core pattern 7. When the optical fiber 14 is suppressed by a block or the like, the height from the surface of the substrate 1 to the upper surface of the upper cladding layer may be adjusted as appropriate so that the height is equal to or less than the diameter of the optical fiber 14. When a lid is formed in advance on the optical fiber mounting groove 11 to form a hole and the optical fiber is inserted into the hole, the diameter is preferably equal to or larger than the diameter of the optical fiber 14.

[Lower cladding groove]
The lower cladding groove 5 is a groove provided in the lower cladding layer between the light transmission core patterns 7, and is located between at least one set of the light transmission core patterns 7 of the plurality of light transmission core patterns 7 (that is, one place). ), More preferably 2 to 3 light transmission core patterns and one core pattern (same as above), and more preferably for all light transmission. It may be provided between the core patterns 7. The width of the lower clad groove 5 is preferably 5 μm to the distance between the light transmission core patterns 7, more preferably 30 μm to the distance between the light transmission core patterns 7, and 50 μm to the light transmission core pattern. It is even better if the distance is less than 7.
The depth of the lower cladding groove 5 is not particularly limited, but is preferably 10 to 100 μm, more preferably 15 to 100 μm, and even more preferably the same thickness as the lower cladding layer 3 described later.

[Core pattern for light transmission]
In the present invention, the light transmission core pattern 7 and the optical fiber guide core 8 formed on the lower clad layer 3 and the substrate 1 are formed by coating a core pattern forming resin or a core pattern forming resin layer (dry layer). A resin layer may be formed by laminating a film and a core pattern may be formed by etching.
In the present invention, an optical fiber connector can be efficiently manufactured by forming the core pattern forming resin layer and then simultaneously etching to form the optical transmission core pattern 7 and the optical fiber guide core 8 at the same time. .

  The core pattern forming resin, in particular, the core pattern forming resin used for the light transmitting core pattern 7 is designed to have a higher refractive index than that of the cladding layer 3, and uses a resin composition that can form the core pattern with actinic rays. be able to.

The thickness of the core pattern forming resin layer (film) is not particularly limited, and the thickness of the dried core pattern forming resin layer is usually adjusted to be 10 to 200 μm. When the thickness of the core pattern 7 for light transmission formed on the lower cladding layer 3 is 10 μm or more, there is an advantage that the alignment tolerance can be increased in coupling with the light emitting / receiving element or the optical fiber after the optical waveguide is formed. When the thickness is 100 μm or less, there is an advantage that the coupling efficiency is improved in coupling with the light emitting / receiving element or the optical fiber after the optical waveguide is formed. From the above viewpoint, the thickness of the light transmission core pattern 7 formed on the lower cladding layer 3 is preferably in the range of 30 to 90 μm, and if the film thickness is appropriately adjusted to obtain the thickness, good.
In addition, when the thickness of the light transmission core pattern after curing is from the optical fiber to the light transmission core pattern, the loss of light is less if the light transmission core pattern exceeds the core diameter of the optical fiber. In the case of transmitting light from the optical fiber to the optical fiber, it is better to adjust so that the rectangle composed of the thickness and width of the core pattern for light transmission is inside the core diameter of the optical fiber within a range that does not adversely affect the optical loss.
Among the plurality of light transmission core patterns 7, the difference between the thickest light transmission core pattern 7 and the thinnest light transmission core pattern 7 can be reduced with the optical fiber connector of the present invention. The difference may be within a range in which light propagation and coupling loss with an optical fiber are good, preferably 0 to 10 μm (variation ± 5 μm), more preferably 0 to 5 μm (variation ± 2.5 μm), more preferably 0 to 3 μm (variation ± 1.5 μm).

  The resin layer for forming a cladding layer (dry film) and the resin layer for forming a core pattern (dry film) are preferably formed on a support film. Examples of the support film include flexible and tough support films such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate and other polyesters, polyethylene, polypropylene and other polyolefins, polyamides, polycarbonates, polyphenylene ethers and polyethers. Preferred examples include sulfide, polyarylate, liquid crystal polymer, polysulfone, polyethersulfone, polyetheretherketone, polyetherimide, polyamideimide, and polyimide. The thickness of the support film is preferably 5 to 200 μm. When it is 5 μm or more, there is an advantage that the strength as a support film is easily obtained, and when it is 200 μm or less, there is an advantage that a gap with the mask at the time of pattern formation becomes small and a finer pattern can be formed. From the above viewpoint, the thickness of the support film is more preferably in the range of 10 to 100 μm, and particularly preferably 15 to 50 μm.

[Optical fiber mounting groove, optical fiber guide, optical fiber guide core]
In the present invention, the method for fixing the optical fiber 14 to the optical fiber mounting groove 11 is not particularly limited. For example, the optical fiber 14 is pressed into the optical fiber mounting groove 11 by holding the fiber with a glass block, and the center of the light transmitting core pattern 7 is centered. And the center of the optical fiber 14 may be aligned and fixed with an adhesive or the like.
At this time, alignment in the direction parallel to the substrate 1 can be performed by the optical fiber guide core 8, and alignment in the direction perpendicular to the substrate 1 can be performed by the substrate 1.

If the distance from the substrate 1 surface of the optical fiber guide portion to the upper surface of the upper cladding layer 9 of the optical waveguide portion 12 is equal to or less than the diameter of the optical fiber 14, the optical fiber is suppressed by a glass block and pushed into the optical fiber mounting groove 11 or the like. Easy to work.
Further, when the height (thickness) of the optical fiber guide core 8 in the optical fiber guide portion is equal to or larger than the radius of the optical fiber 14, the optical fiber 14 is hardly displaced.
The width of the optical fiber mounting groove 11 between the optical fiber guide cores 8 may be equal to or larger than the diameter of the optical fiber. From the viewpoint of the mountability and tolerance of the optical fiber, it is 0.1 to 10 μm from the diameter of the optical fiber. A wider width is better. The height of the optical fiber guide core 8 may be higher than the radius of the optical fiber, and may be lower than the diameter of the optical fiber. The height of the optical fiber guide portion (including the upper clad layer 10) is more preferably 5 μm or more than the radius of the optical fiber and 3 μm or more lower than the diameter, which is more preferable because the mountability when holding the optical fiber 14 with a glass block or the like is good.
The height of the optical fiber guide portion (including the upper clad layer 10) when the optical fiber mounting groove 11 is previously covered with a lid to form a hole and the optical fiber is inserted into the hole for mounting is the optical fiber. It is sufficient if it is equal to or larger than the diameter. It is preferable that the diameter is higher than the diameter of the optical fiber by 5 μm or more and the diameter +15 μm or less because the displacement between the optical fiber and the optical waveguide can be suppressed.
The optical fiber connector of the present invention has a height (maximum height) from the surface of the substrate 1 to the upper cladding layer 9 of the optical waveguide portion 12 and a height from the surface of the substrate 1 to the upper cladding layer 10 of the optical fiber guide portion ( The difference in maximum height can be reduced. The difference may be within a range in which the optical fiber can be satisfactorily suppressed or the lid can be installed well, and the coupling loss between the optical fiber 14 and the optical waveguide portion 12 is good, preferably 0 to 10 μm, more preferably 0. It is -5 micrometers, More preferably, it is 0-3 micrometers.

[Optical fiber]
In the present invention, specifically, if the diameter of the optical fiber is 200 μm or less, it is preferable from the viewpoint that the film thickness of the resin layer (film) for forming the core pattern is easy to control, and an optical fiber having a diameter of 125 μm or 80 μm is used. More preferably, it is used.

[Optical path conversion mirror]
An optical path conversion mirror 13 may be provided on the optical axis of the core pattern 7 for light transmission. The optical path conversion mirror 13 is not particularly limited as long as the light propagated through the light transmission core pattern 7 can be optically converted in a direction substantially perpendicular to the substrate 1, and the optical path is preferably 45 to 135 °. The optical path is preferably changed to 75 to 105 °, more preferably 87 to 93 °. The direction of the optical path conversion may be on the lower clad layer 3 side or the upper clad layer 9 side. When the light path is changed to the lower clad layer 3 side and transmitted through the substrate 1, it has transparency with respect to the wavelength of the light transmitted through the substrate 1, or the portion where the light is transmitted is transparent or opening. It is preferable.
The optical path conversion mirror 13 may be an air reflection mirror in which an inclined surface of approximately 45 ° is formed on the optical axis of the light transmission core pattern 7 or a metal reflection mirror in which a reflective metal layer is formed on the inclined surface.

A method for forming the optical path conversion mirror 13 is not particularly limited, and a method of forming an inclined surface for the optical path conversion mirror 13 by using laser ablation or cutting such as a dicing saw is preferable. It is preferable to form the optical path conversion mirror 13 on the optical axis of the core pattern 7 for light transmission in the same process because a plurality of optical path conversion mirrors 13 can be efficiently formed and the correlation between these positions can be easily obtained.
In the present invention, an air reflecting mirror using a difference in refractive index between resin and air is preferable, but a metal reflecting mirror having a reflecting metal layer on the reflecting surface may be used. The method for forming the reflective metal layer is not particularly limited, and examples thereof include vapor deposition, sputtering, and plating. As the type of the reflective metal layer, various metals such as Au, Ag, Cu, Al, Cu, Ni, Ti, and alloys thereof are preferably used.
Hereinafter, the manufacturing method of the optical fiber connector of this invention is demonstrated in detail.

(Process A)
In the method for manufacturing an optical fiber connector of the present invention, a lower clad layer forming resin layer is formed on the substrate 1 as step A, and the lower clad layer removing portion 6 including the optical fiber mounting groove in the optical fiber guide portion is formed by etching. And a lower cladding groove 5 in the optical waveguide portion. By forming these simultaneously, the lower cladding layer removing portion 6 and the lower cladding groove 5 with high positional accuracy can be formed. At this time, if the lower clad layer removing portion 6 and the lower clad groove 5 are connected, the flowability of the resin is improved when forming the resin layer for forming the core pattern and the resin layer for forming the upper clad layer later. It is easy to obtain flatness and the generation of bubbles is also suppressed.

(Process B)
In the method for manufacturing an optical fiber connector of the present invention, as step B, a core pattern forming resin layer is formed from the lower clad layer 3 formation surface side, and a light transmission core pattern 7 is formed on the lower clad layer 3 by etching. At the same time, the optical fiber guide core 8 is formed. The optical fiber guide core 8 becomes a side wall of the optical fiber mounting groove 11. In the present invention, these can be formed simultaneously. As a result, high positional accuracy between the optical fiber mounting groove 11 and the optical transmission core pattern 7 can be ensured. When the optical fiber 14 is mounted in the optical fiber mounting groove 11, the optical waveguide portion 12 and the optical fiber 14 are satisfactorily formed. Can be aligned.

(Process C)
In the method for manufacturing an optical fiber connector of the present invention, as step C, a resin layer for forming an upper clad layer is formed from the light transmitting core pattern 7 forming surface side, and etching is performed to form an upper portion on the optical fiber mounting groove in the optical fiber guide portion Remove the cladding layer.

(Process D)
In the optical fiber connector manufacturing method of the present invention, as step D, the substrate groove 2 is formed so as to sandwich the optical transmission core pattern 7 and the optical fiber mounting groove 11 forming portion in the substrate 1, or the optical fiber mounting groove. It is preferable to form the substrate groove 2 at the end of the 11 forming portion on the optical waveguide portion side.
In addition, the process D is performed before the process B or the process C from a viewpoint of suppressing generation | occurrence | production of the bubble at the time of forming the resin layer for core pattern formation, and the resin layer for upper clad layer formation.

[etching]
In the present invention, the core pattern forming resin layer or the cladding layer forming resin layer is etched and patterned. Examples of the etching method include dry etching such as RIE (Reactive Ion Etching), and wet etching in which a resin is dissolved or swelled and removed using a solvent or an alkaline solution. Before performing dry etching and wet etching, an etching resist pattern that is not or hardly etched is formed on the core pattern forming resin layer or the clad layer forming resin layer, and the core pattern forming resin layer or the portion without the etching resist pattern is formed. A method of removing the clad layer forming resin layer and then removing the etching resist pattern may be used. When wet etching is performed, a resin that can be etched with a solution or an alkaline solution may be used for the core pattern forming resin layer or the clad layer forming resin layer.
As another wet etching method, there is a method in which the core pattern forming resin layer or the upper clad layer forming resin layer is a photosensitive resin layer, photocured with actinic rays, and wet etched. If this method is used, a step of forming an etching resist pattern on the resin layer and a step of removing the etching resist pattern are unnecessary.
Wet etching is preferable because patterns with different depths (such as a light transmission core pattern and an optical fiber guide core) can be easily formed.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited.
Example 1
<Preparation of a resin film for forming a cladding layer>
[Production of (A) (meth) acrylic polymer (base polymer)]
46 parts by mass of propylene glycol monomethyl ether acetate and 23 parts by mass of methyl lactate were weighed in a flask equipped with a stirrer, a cooling pipe, a gas introduction pipe, a dropping funnel, and a thermometer, and stirred while introducing nitrogen gas. . The liquid temperature was raised to 65 ° C., 47 parts by mass of methyl methacrylate, 33 parts by mass of butyl acrylate, 16 parts by mass of 2-hydroxyethyl methacrylate, 14 parts by mass of methacrylic acid, 2,2′-azobis (2,4-dimethylvaleronitrile ) A mixture of 3 parts by mass, 46 parts by mass of propylene glycol monomethyl ether acetate and 23 parts by mass of methyl lactate was added dropwise over 3 hours, followed by stirring at 65 ° C. for 3 hours, and further stirring at 95 ° C. for 1 hour. A) A (meth) acrylic polymer solution (solid content: 45% by mass) was obtained.

[Measurement of weight average molecular weight]
(A) The result of having measured the weight average molecular weight (standard polystyrene conversion) of (meth) acrylic polymer using GPC ("SD-8022", "DP-8020", and "RI-8020" by Tosoh Corp.). It was 3.9 × 10 ⁴ . As the column, “Gelpack GL-A150-S” and “Gelpack GL-A160-S” manufactured by Hitachi Chemical Co., Ltd. were used.
[Measurement of acid value]
As a result of measuring the acid value of (A) (meth) acrylic polymer, it was 79 mgKOH / g. The acid value was calculated from the amount of 0.1 mol / L potassium hydroxide aqueous solution required to neutralize the (A) (meth) acrylic polymer solution. At this time, the point at which the phenolphthalein added as an indicator changed color from colorless to pink was defined as the neutralization point.

[Preparation of resin varnish for forming clad layer]
As a base polymer, 84 parts by mass (solid content 38 parts by mass) of the (A) (meth) acrylic polymer solution (solid content 45% by mass), (B) urethane (meth) acrylate having a polyester skeleton as a photocuring component ( Shin-Nakamura Chemical Co., Ltd. “U-200AX”) 33 parts by mass, and urethane (meth) acrylate having a polypropylene glycol skeleton (Shin-Nakamura Chemical Co., Ltd. “UA-4200”) 15 parts by mass, (C ) As a thermosetting component, a polyfunctional block isocyanate solution (solid content 75% by mass) obtained by protecting isocyanurate type trimer of hexamethylene diisocyanate with methyl ethyl ketone oxime (“Sumijour BL3175” manufactured by Sumika Bayer Urethane Co., Ltd.) 20 1 part by mass (solid content 15 parts by mass), (D) 1- [4- 2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one (“Irgacure 2959” manufactured by Ciba Japan Co., Ltd.), 1 part by weight, bis (2,4,6-trimethylbenzoyl) ) 1 part by mass of phenylphosphine oxide (“Irgacure 819” manufactured by Ciba Japan Co., Ltd.) and 23 parts by mass of propylene glycol monomethyl ether acetate as an organic solvent for dilution were mixed with stirring. After pressure filtration using a polyflon filter having a pore size of 2 μm (“PF020” manufactured by Advantech Toyo Co., Ltd.), degassing was performed under reduced pressure to obtain a resin varnish for forming a cladding layer.

[Preparation of resin film for forming clad layer]
The resin varnish for forming a clad layer obtained above is coated on a non-treated surface of a PET film (“Cosmo Shine A4100” manufactured by Toyobo Co., Ltd., thickness 50 μm) as a support film. MC, manufactured by Hirano Tech Seed Co., Ltd., dried at 100 ° C. for 20 minutes, and then a surface release treated PET film (“Purex A31” manufactured by Teijin DuPont Films Co., Ltd., thickness 25 μm) is pasted as a protective film. A resin film for forming a cladding layer was obtained.
At this time, the thickness of the resin layer formed from the clad layer forming resin varnish can be arbitrarily adjusted by adjusting the gap of the coating machine, and the thickness after drying will be described later.

<Preparation of resin film for core pattern formation>
(A) As a base polymer, 26 parts by mass of a phenoxy resin (trade name: Phenotote YP-70, manufactured by Toto Kasei Co., Ltd.), and (B) 9,9-bis [4- (2- Acrylyloxyethoxy) phenyl] fluorene (trade name: A-BPEF, Shin-Nakamura Chemical Co., Ltd.) 36 parts by mass, and bisphenol A type epoxy acrylate (trade name: EA-1020, Shin-Nakamura Chemical Co., Ltd.) 36 parts by mass, (C) 1 part by mass of bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (trade name: Irgacure 819, manufactured by Ciba Specialty Chemicals) -[4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one (trade name: Irgacu 2959, manufactured by Ciba Specialty Chemicals Co., Ltd.), and the core pattern was prepared in the same manner and under the same conditions as in the above-mentioned preparation of the resin varnish for forming a clad layer, except that 40 parts by mass of propylene glycol monomethyl ether acetate was used as the organic solvent. A forming resin varnish was prepared. Thereafter, pressure filtration and degassing under reduced pressure were performed in the same manner and conditions as described above.
On the non-treated surface of the PET film (trade name: Cosmo Shine A1517, manufactured by Toyobo Co., Ltd., thickness: 16 μm) as a support film, the core pattern-forming resin varnish obtained above is After applying and drying in the same manner, a release PET film (trade name: PUREX A31, Teijin DuPont Films Co., Ltd., thickness: 25 μm) is attached as a protective film so that the release surface is on the resin side. A resin film for forming a core pattern was obtained.
At this time, the thickness of the resin layer formed from the resin varnish for core pattern formation can be arbitrarily adjusted by adjusting the gap of the coating machine, and the thickness after drying will be described later.

[Production of Substrate 1]
The protective film of the 15 μm-thick clad layer-forming resin layer (film) obtained above was peeled off, and a 100 mm × 100 mm polyimide film (polyimide; Upilex RN (manufactured by Ube Nitto Kasei Co., Ltd.), thickness: 25 μm) Placed on top. Then, after vacuuming to 500 Pa or less using a vacuum pressurization type laminator (MVLP-500, manufactured by Meiki Seisakusho Co., Ltd.), thermocompression bonding is performed under conditions of a pressure of 0.4 MPa, a temperature of 80 ° C., and a pressurization time of 30 seconds. And laminated.
Next, ultraviolet light (wavelength 365 nm) was irradiated from the support film side with 250 mJ / cm ² through a negative photomask having a light-shielding part of 100 μm with an ultraviolet exposure machine (EXM-1172, manufactured by Oak Manufacturing Co., Ltd.). Thereafter, the support film was peeled off, and the resin layer for forming the clad layer was etched using a developing solution (1 mass% potassium carbonate aqueous solution). Subsequently, the substrate 1 was washed with water, dried and cured by heating at 170 ° C. for 1 hour, and a substrate 1 with a substrate groove 2 having a width of 100 μm and a thickness of 15 μm was produced.

[Fabrication of optical fiber connector]
The protective film of the 37.5 μm-thick clad layer forming resin film obtained above was peeled off and laminated under the same conditions as described above using the vacuum laminator from the substrate groove 2 forming surface side. 110 μm × 10 mm × 12 locations (250 μm pitch) openings (lower cladding layer) and 110 μm × 30 mm × 10 mm × 13 locations (250 μm pitch) openings (dummy lower cladding layer 4) are separated by 100 μm, and each is half pitch ( 125 μm) The shifted negative type photomask is aligned so that the part separated by 100 μm overlaps the substrate groove 2, and ultraviolet light (wavelength 365 nm) from the support film side with an ultraviolet exposure machine (EXM-1172, manufactured by Oak Manufacturing Co., Ltd.) Was irradiated with 250 mJ / cm ² . Thereafter, the support film was peeled off, and the lower clad layer forming resin was etched using a developer (1 mass% potassium carbonate aqueous solution). Subsequently, it was washed with water, dried by heating at 170 ° C. for 1 hour, and cured to form a lower cladding layer 3 and a dummy lower cladding layer 4. In addition, in order to make the pattern density uniform in portions other than the described pattern, dummy patterns with a width of 110 μm were formed at a pitch of 250 μm.

[Production of core pattern]
Next, the 71 μm-thick core pattern forming resin film from which the protective film has been peeled is placed on the lower clad layer 3 forming surface side, SUS304 having a thickness of 1 mm is applied thereon, and the substrate 1 side is further thickened. 1 mm of SUS304 was applied, and lamination was performed under the same conditions as described above using the vacuum laminator. Next, using the above-described vacuum pressurization type laminator (MVLP-500, manufactured by Meiki Seisakusho Co., Ltd.), after vacuuming to 500 Pa or less, thermocompression bonding under conditions of pressure 0.4 MPa, temperature 70 ° C., pressurization time 30 seconds. did. Thereafter, each of the optical transmission core patterns is opened through a negative photomask having an opening having a width of 50 μm (pitch: 250 μm, 12) and an optical fiber guide core 8 having a width of 121 μm (pitch: 250 μm, 13). The core pattern 7 is aligned so that the optical fiber guide core 8 embeds the dummy lower clad layer 4 on each lower clad layer 3, and ultraviolet rays (wavelength 365 nm) are 700 mJ / cm by the ultraviolet exposure machine. ² exposures, followed by post-exposure heating at 80 ° C. for 5 minutes. Thereafter, the PET film as the support film was peeled off, and the core pattern was etched using a developer (propylene glycol monomethyl ether acetate / N, N-dimethylacetamide = 8/2, mass ratio). Then, it wash | cleaned using the washing | cleaning liquid (isopropanol), and it heat-dried for 10 minutes at 100 degreeC, and formed the core pattern 7 for optical transmission, and the optical fiber guide core 8. FIG. The size of each pattern in the optical fiber guide core 8 is such that when the optical fiber is fixed to the optical fiber mounting groove 11, the optical fiber 14 is bonded to the optical transmission core pattern 7 at a position where an optical signal can be transmitted and received. Designed to be
The cross-sectional shape of the optical transmission core pattern 7 was 50 μm × 50 μm, the height of the optical fiber guide core was 87.4 μm, and the width was 121 μm (the distance between the optical fiber guide cores was 129 μm).
In addition, in order to make the pattern density uniform in portions other than the described pattern, dummy patterns having a width of 50 μm were formed at a pitch of 250 μm.

Next, a 92 μm-thick clad layer-forming resin layer (film) from which the protective film has been peeled off is placed, SUS304 with a thickness of 1 mm is applied from the top, and SUS304 with a thickness of 1 mm is further applied to the substrate 1 side. Lamination was performed using a laminator under the same conditions as described above. Further, the negative photomask used in forming the lower clad layer 3 is exposed to 150 J / cm ^{2 of} ultraviolet rays (wavelength 365 nm) using a negative photomask having the entire optical waveguide portion opened, and then the support film. The upper cladding layer forming resin layer (film) in the optical fiber mounting groove 11 portion was removed by etching using a developer (1 mass% potassium carbonate aqueous solution). Subsequently, it was washed with water, heated and dried at 170 ° C. for 1 hour, and cured to produce an optical fiber connector for 250 channels with a pitch of 250 μm and a fiber diameter of 125 μm.
In the obtained optical fiber connector, the distance from the substrate 1 surface to the upper surface of the optical waveguide was 122 μm at the maximum, and the height from the substrate 1 surface of the optical fiber guide portion to the upper cladding layer 10 was 123 μm at the maximum. The maximum thickness of the 12 light transmission core patterns was 51 μm, the minimum value was 49.2 μm, and the variation was ± 0.9 μm. When ten optical fiber connectors were manufactured by this manufacturing method, bubbles were never generated in the optical fiber mounting groove 11 both when the core pattern was formed and when the upper clad layer was formed.

[Formation of optical path conversion mirror]
A 45 ° optical path conversion mirror 13 was formed using a dicing saw (DAC552, manufactured by DISCO Corporation) from the upper clad layer 9 side of the obtained optical waveguide section 12.
Further, the substrate 1 was processed to 3 mm × 20.1 mm using the above dicing saw provided with a rectangular blade.
In the optical fiber mounting groove 11 of the optical fiber connector obtained as described above, a 250 μm pitch, 12-channel optical fiber 14 (core diameter: 50 μm, cladding diameter: 125 μm) is suppressed by a glass block, and the optical fiber mounting groove 11 is used. The optical fiber 14 is bonded to the light transmission surface of the optical transmission core pattern 7 of the optical waveguide portion 12 so that an optical signal can be transmitted from the optical fiber 14, and the optical fiber 14 may be displaced. There wasn't. The variation in optical loss was also ± 0.2 dB.
When the core pattern forming resin varnish obtained above as an adhesive for fixing the optical fiber 14 was dropped onto the optical fiber mounting groove 11, it satisfactorily went around all the optical fiber mounting grooves 11 through the substrate groove 2.

Comparative Example 1
In Example 1, the lower cladding layer 3 is formed directly on the polyimide without forming the substrate groove 2, and the negative photomask used for patterning the lower cladding layer 3 is patterned into the upper cladding layers 9, 10. An optical fiber connector was fabricated in the same manner except that the negative photomask used in Step 1 was changed and the lower cladding groove 5 was not formed.
In the obtained optical fiber connector, the distance from the substrate 1 surface to the upper surface of the optical waveguide was 134 μm at the maximum, and the height from the substrate 1 surface of the optical fiber guide portion to the upper cladding layer 10 was 126 μm at the maximum. The maximum thickness of the 12 light transmitting core patterns was 58.0 μm, the minimum value was 46.0 μm, and the variation was ± 6.0 μm. The core pattern for light transmission at the center tends to be thick. Furthermore, when 10 optical fiber connectors were produced by this manufacturing method, 9 bubbles were generated in the optical fiber mounting groove 11 when the core pattern was formed, and 8 bubbles were generated when the upper cladding layer was formed. It was.
In the optical fiber mounting groove 11 of the optical fiber connector obtained as described above, the optical fiber mounting groove 8 is obtained by holding the optical fiber 14 (core diameter: 50 μm, clad diameter: 125 μm) of 250 μm pitch and 12 channels with a glass block. The optical fiber 14 is bonded to the light transmission surface of the optical transmission core pattern 7 of the optical waveguide portion 12 so that an optical signal can be transmitted from the optical fiber 14, and the optical fiber 14 may be displaced. Although there was no variation, the variation in optical loss was ± 0.6 dB.

  Further, when the core pattern forming resin varnish obtained above as an adhesive for fixing the optical fiber 14 is dropped on the optical fiber mounting groove 11, it takes time to wrap around all the optical fiber mounting grooves 11. Bubbles remained between the optical waveguides.

As described above in detail, the optical fiber connector of the present invention can reduce the thickness variation of a plurality of core patterns for light transmission, and the difference between the height to the surface of the upper cladding layer of the optical waveguide and the height of the optical fiber guide portion. Therefore, variation in coupling loss with the optical fiber can be reduced.
Therefore, it is useful as a photoelectric conversion substrate for optical fibers.

1. Substrate 2. 2. substrate groove Lower clad layer 4. 4. Dummy lower cladding layer 5. Lower cladding groove 6. Lower clad layer removal section including optical fiber mounting groove 7. Core pattern for light transmission 8. Optical fiber guide core Upper cladding layer (optical waveguide)
10. Upper cladding layer (optical fiber guide)
11. 10. Optical fiber mounting groove Optical waveguide section 13. Optical path conversion mirror 14. Optical fiber

Claims (14)

  An optical fiber in which an optical waveguide portion having a lower clad layer, a plurality of light transmission core patterns, an upper clad layer, and an optical fiber guide portion having an optical fiber mounting groove for fixing the optical fiber is provided on a substrate. The optical waveguide portion has a lower clad groove formed in at least one position between a plurality of light transmission core patterns, and the optical fiber guide portion includes an optical fiber to be fixed and the light transmission core pattern. An optical fiber connector in which the optical fiber mounting groove is arranged so that the optical fiber can be joined to a position where the optical signal can be transmitted.   2. The optical fiber connector according to claim 1, wherein the lower clad groove is formed so as to divide the lower clad layer at at least one location between a plurality of core patterns for light transmission.   The optical fiber connector according to claim 1, wherein the lower cladding groove and the core pattern for light transmission extend in a substantially parallel direction.   The optical fiber connector according to any one of claims 1 to 3, wherein a bottom surface of the optical fiber mounting groove and a bottom surface of the lower cladding groove are flush with each other.   The optical fiber connector according to any one of claims 1 to 4, wherein a variation in height of the plurality of core patterns for light transmission is ± 5 µm or less.   The optical fiber connector according to any one of claims 1 to 5, wherein a difference between a height from the substrate surface to an upper surface of the optical waveguide portion and a height from the upper surface of the optical fiber guide portion is 10 µm or less. An optical fiber in which an optical waveguide portion having a lower clad layer, a plurality of light transmission core patterns, an upper clad layer, and an optical fiber guide portion having an optical fiber mounting groove for fixing the optical fiber is provided on a substrate. A method for manufacturing a connector, comprising:
Forming a resin layer for forming a lower clad layer on the substrate, and forming, by etching, a lower clad layer removing portion including an optical fiber mounting groove in the optical fiber guide portion, and forming a lower clad groove in the optical waveguide portion;
A resin layer for forming a core pattern is formed from the lower clad layer forming surface side, and an optical transmission core pattern on the lower clad layer in the optical waveguide portion and light on the lower clad layer in the optical fiber guide portion are etched. Forming a side wall of the fiber mounting groove; and
Manufacturing of an optical fiber connector comprising a step C of forming a resin layer for forming an upper clad layer from the light transmission core pattern forming surface side and removing the upper clad layer on the optical fiber mounting groove in the optical fiber guide portion by etching. Method.   8. The method of manufacturing an optical fiber connector according to claim 7, wherein in step A, the lower clad layer removing portion including the optical fiber mounting groove in the optical fiber guide portion and the lower clad groove in the optical waveguide portion are connected to each other.   The method of manufacturing an optical fiber connector according to claim 7 or 8, wherein an optical path conversion mirror is formed on an optical axis of a core pattern for light transmission in the optical waveguide portion.   The optical fiber according to any one of claims 7 to 9, wherein at least one of the lower clad layer forming resin layer, the core pattern forming resin layer, and the upper clad layer forming resin layer is a photosensitive resin layer. A method for manufacturing a connector.   The optical fiber connector production according to any one of claims 7 to 10, wherein at least one of the lower clad layer forming resin layer, the core pattern forming resin layer, and the upper clad layer forming resin layer is a dry film. Method.   A substrate groove is formed on the substrate so as to sandwich the optical transmission core pattern and the optical fiber mounting groove forming portion, or a substrate groove is formed at the end of the optical fiber mounting groove forming portion on the optical waveguide portion side. The method of manufacturing an optical fiber connector according to claim 7, further comprising a step D, wherein the step D is performed before the step B or the step C.   The optical fiber connector obtained by the manufacturing method of the optical fiber connector in any one of Claims 7-12.   An optical fiber cable in which an optical fiber is mounted in the optical fiber mounting groove of the optical fiber connector according to any one of claims 1 to 6.

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