JP2004078019A - Optical fiber, its processing method, and metallic mold for optical fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make laser beams outputted from a semiconductor laser efficiently incident on an optical fiber. <P>SOLUTION: A waveguide 2 which comprises a core layer 4 for guiding laser beams outputted from a laser diode 3 to the end surface of the optical fiber 2 and a cladding layer 5, wherein one end of the core layer 4 is positioned at an incidence opening of the end face of the optical fiber 1 and the other end is formed at a prescribed position that can be positioned on the light emitting surface of the laser diode 3, is formed integrally with the end face side of the optical fiber 1. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical fiber for causing a laser beam output from a laser diode to enter an entrance of an optical fiber, a method of processing the same, and a mold for an optical fiber used in the processing method.
[0002]
[Prior art]
An edge-emitting semiconductor laser outputs a laser beam with a spread. In order to optically couple the semiconductor laser and the optical fiber, optical means such as a lens is widely used in order to efficiently input a widened laser beam output from the semiconductor laser to the optical fiber.
[0003]
In such an optical coupling method between a semiconductor laser and an optical fiber, it is necessary to position a plurality of lenses with extremely high precision, and it takes a long time to perform the adjustment, and the manufacturing cost increases.
[0004]
On the other hand, a method using a waveguide as an optical coupling method between a semiconductor laser and an optical fiber is described in, for example, JP-A-2001-156377. In this method, since the waveguide is configured to absorb the temperature expansion and contraction of the peripheral components, the elastic modulus of the waveguide is low. It is difficult to increase the alignment accuracy of the axis.
[0005]
[Problems to be solved by the invention]
As described above, it is difficult to increase the alignment accuracy between the optical fiber and the waveguide, and it is not possible to efficiently cause the widened laser beam output from the semiconductor laser to enter the optical fiber.
[0006]
Therefore, an object of the present invention is to provide an optical fiber capable of efficiently entering a laser beam output from a semiconductor laser into an optical fiber, a method of processing the same, and a mold for an optical fiber used in the processing method.
[0007]
[Means for Solving the Problems]
The present invention relates to an optical fiber, a core layer formed integrally with the end face of the optical fiber and guiding a laser beam output from a laser diode to the end face of the optical fiber, and a core layer formed around the core layer and the end face of the optical fiber. One end of the core layer is positioned at the entrance of the end face of the optical fiber, and the other end is provided with a waveguide formed at a predetermined position that can be positioned on the light emitting surface of the laser diode. An optical fiber having a structure.
[0008]
The present invention provides an optical fiber, a laser diode mounted on a substrate, a core layer integrally formed on the end face of the optical fiber, and guiding a laser beam output from the laser diode to the end face of the optical fiber, And a cladding layer formed on the outer periphery of the optical fiber end face side, one end of the core layer is positioned at the entrance of the optical fiber end face, and the other end is formed at a predetermined position that can be positioned on the light emitting surface of the laser diode. And a tip structure comprising an optical fiber fixing jig for positioning the other end of the core layer on the light emitting surface of the laser diode and fixing the waveguide and the optical fiber on the substrate. Optical fiber.
[0009]
According to the present invention, a clad layer having a groove for forming a core layer, one end of which is positioned at an entrance of an optical fiber end face and the other end of which can be positioned at a light emitting surface of a laser diode, is integrally formed on the outer periphery of the optical fiber end face. And a step of forming a core layer by injecting a core material into a core layer forming groove.
[0010]
In the optical fiber processing method of the present invention, when the clad layer is formed on a part of the outer periphery of the optical fiber end face side, after the core layer forming step, a step of forming a clad layer on the remaining half circumference of the optical fiber end face side. The cladding layer is formed of an optical two-component curable silicone resin, and the core layer is formed of an optical two-component curable silicone resin having a higher refractive index than the silicone resin.
[0011]
The present invention provides a core layer forming part that forms a core layer for guiding a laser beam output from a laser diode, an optical fiber guide that positions an entrance of an optical fiber end face to the core layer forming part, and an optical fiber end face part. An optical fiber holding jig pressed against a fiber guide, a mold for integrally molding a cladding layer having a core layer forming groove by a core layer forming portion on an outer periphery of an optical fiber end face side, and using this mold A core material molding die for mounting the core material into a core layer forming groove formed by the core layer forming portion, the core material forming die being mounted on the clad layer formed by molding. This is a fiber mold.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0013]
1A and 1B are configuration diagrams of an optical fiber. FIG. 1A is a top view and FIG. 1B is a cross-sectional view. A waveguide 2 is integrally provided at the tip of the optical fiber 1. The waveguide 2 includes a core layer 4 for guiding a laser beam output from the laser diode 3 and a clad layer 5 formed on the outer periphery of the core layer 4. The core layer 4 has a light emitting surface side of the laser diode 3 formed in a rectangular shape of, for example, 1 × 200 μm, and an optical fiber 1 side formed in a quadrangular pyramid of, for example, 30 × 30 μm.
[0014]
The substrate 6 includes a pedestal portion 6a of the laser diode 3 and a mounting portion 6b of the optical fiber 1. The pedestal portion 6a is formed higher than the mounting portion 6b of the optical fiber 1 by a predetermined height. The upper surfaces of the pedestal portion 6a and the mounting portion 6b are formed to be flat. The laser diode 3 is mounted on the base 6a.
[0015]
The optical fiber 1 is fixed by an optical fiber fixing jig 7 on the mounting portion 6b. To fix the optical fiber 1, the waveguide 2 formed at the tip of the optical fiber 1 is brought into close contact with the light emitting surface of the laser diode 3. That is, in the laser diode 3, the spread angle of the output laser beam is, for example, 40 ° in one direction (X direction) and 10 ° in the other direction (Y direction) perpendicular to the one direction. Therefore, the waveguide 2 is fixed in close contact with the light emitting surface of the laser diode 3. At this time, the core layer 4 in close contact with the light emitting surface side of the laser diode 3 in the waveguide 2 is positioned on the light emitting surface of the laser diode 3. That is, the height position of the core layer 4 formed in the waveguide 2 is formed so as to match the height position of the light emitting surface of the laser diode 3 mounted on the pedestal 6a. Therefore, the core layer 4 of the optical fiber 1 can be roughly positioned on the light emitting surface of the laser diode 3 only by being placed on the mounting portion 6b, and then finely adjusted for positioning.
[0016]
After this positioning, the optical fiber 1 is fixed on the mounting portion 6b of the substrate 6 via the optical fiber fixing jig 7. At this time, the optical fiber fixing jig 7 is fixed on the mounting portion 6b by, for example, an ultraviolet curable adhesive 8.
[0017]
Next, an optical fiber tip processing mold used in the method of processing the optical fiber tip structure will be described.
[0018]
2A to 2C are configuration diagrams of an optical fiber mold. FIG. 2A is a top view, FIG. 2B is a cross-sectional view, and FIG. 2C is a front view. . The mold body 10 is formed in a box shape with an open top.
[0019]
An optical fiber guide 11 and a core layer forming base 12 are formed on the bottom surface of the mold body 10. The optical fiber guide 11 is formed in a V-shaped groove as shown in FIG. A core shape transfer portion 13 is formed on the upper surface of the core layer forming base 12. In order to form the core layer 4, the core shape transfer section 13 has a light emitting surface side of the laser diode 3 on one end side of, for example, a rectangle of 1 × 200 μm and an optical fiber 1 side on the other end side of, for example, 30 ×. It is formed on a convex part of a quadrangular pyramid of 30 μm. When the optical fiber 1 is placed on the optical fiber guide 11, the height of the core shape transfer unit 13 above the bottom surface of the mold body 10 is determined by the core layer of the optical fiber 1 and the optical fiber of the core shape transfer unit 13. It is formed so that the other end which is one side coincides with the other side.
[0020]
An optical fiber insertion packing 14 for inserting the optical fiber 1 into the mold body 10 and mounting the optical fiber 1 on the optical fiber guide 11 is formed on the side surface of the mold body 10 on the side of the optical fiber guide 11. . The optical fiber insertion packing 14 is formed in a circular shape having substantially the same diameter as the outer diameter of the optical fiber 1, and the center of the packing 14 coincides with the height position of the core shape transfer unit 13 on the optical fiber 1 side. Further, the lower part of the outer peripheral edge of the optical fiber insertion packing 14 substantially coincides with the height position of the optical fiber guide 11.
[0021]
The upper ends of both sides of the mold body 10 are provided with fixing ends 15a and 15b, respectively. An optical fiber holding jig 16 is attached between these fixing ends 15a and 15b by optical fiber holding jig fixing brackets 17a and 17b. These optical fiber holding jig fixing brackets 17 a and 17 b are composed of, for example, bolts 18 and nuts 19. The optical fiber holding jig 16 has a bar shape, and an optical fiber holding end 16a is formed below the center.
[0022]
Next, a method of processing an optical fiber will be described with reference to manufacturing process diagrams shown in FIGS. 3A to 3F show a cross-sectional view in a plane direction including the traveling direction of light on the left side, and a cross-sectional view including a plane perpendicular to the traveling direction of light on the right side.
[0023]
First, the optical fiber 1 is inserted into the mold main body 10 from the optical fiber insertion packing 14 and placed on the optical fiber guide 11 as shown in FIG. At this time, the core layer 1a of the optical fiber 1 is aligned with the core shape transfer portion 13, and the end face of the optical fiber 1 is brought into close contact with the core shape transfer portion 13. Then, the optical fiber 1 is held down on the optical fiber guide 11 by the optical fiber holding end 16a of the optical fiber holding jig 16 by the optical fiber holding jig fixtures 17a and 17b, and is fixed. 1b is a cladding layer of the optical fiber 1.
[0024]
Next, for example, a two-component curable silicone resin for optics is poured into the mold body 10, and as shown in FIG. 3B, a cladding layer of the waveguide 2 (hereinafter, referred to as a lower cladding layer). 5a is formed integrally with the end of the optical fiber 1. The lower clad layer 5a may be formed by, for example, injection molding or transfer molding. The lower cladding layer 5a is formed in a portion approximately half of the optical fiber 1 in the radial direction.
[0025]
The material for forming the lower cladding layer 5a may be, for example, an acrylic resin or a polycarbonate resin.
[0026]
Next, the lower clad layer 5a and the optical fiber 1 are taken out of the mold body 10 as shown in FIG. 3C. In the lower cladding layer 5a, a core shape transfer groove 20 to which the shape of the core shape transfer portion 13 is transferred is formed. The end portion of the core shape transfer groove 20 on the optical fiber 1 side is formed so as to coincide with the core layer 1a of the optical fiber 1 as a matter of course.
[0027]
Next, as shown in FIG. 3D, the lower clad layer 5a and the optical fiber 1 are integrally mounted on a core material forming die 21. The core material forming die 21 has an L-shaped cross section, and a core material injection gate 22 is provided at a portion corresponding to the core shape transfer groove 20. In addition, since the core material is injected into the core shape transfer groove 20, the core shape transfer groove 20 is directed upward as an integral part of the lower cladding layer 5a and the optical fiber 1.
[0028]
Next, as shown in FIG. 3E, a core material 23, for example, an optical two-component curing type silicone resin having a higher refractive index than the silicone resin used for forming the lower clad layer 5a is injected into the core material. The gate 22 is injected into the core shape transfer groove 20. Then, the core material 23 is cured, whereby the core layer 4 is formed.
[0029]
Next, the lower clad layer 5 a on which the core layer 4 is formed and the optical fiber 1 are taken out of the core material forming die 21.
[0030]
Next, the lower clad layer 5a on which the core layer 4 is formed and the optical fiber 1 are integrated into an upper clad layer forming mold 24 as shown in FIG. The upper cladding layer forming die 24 is formed in a box shape with an open top. In the upper cladding layer forming die 24, the lower cladding layer 5a is mounted on the bottom surface of the upper cladding layer forming die 24. Then, for example, an optical two-component curing type silicone resin is poured into the upper cladding layer molding die 24, and the upper cladding layer 5b is integrally formed on the end of the optical fiber 1 by curing the silicone resin. The upper clad layer 5b is formed by, for example, injection molding or transfer molding.
[0031]
Thus, the lower clad layer 5a and the upper clad layer 5b are integrated, and the lower clad layer 5a and the upper clad layer 5b form the clad layer 5.
[0032]
When the clad layer 5 may be air, the upper clad layer 5b need not be formed.
[0033]
Thereafter, the optical fiber 1 with the waveguide 2 formed at the tip is mounted on the mounting portion 6b of the substrate 6 on which the laser diode 3 is mounted, as shown in FIGS. 1A and 1B. The waveguide 2 is in close contact with the light emitting surface of the laser diode 3, and the core layer 4 is easily positioned on the light emitting surface of the laser diode 3.
[0034]
After this positioning, the optical fiber 1 is fixed on the mounting portion 6b of the substrate 6 via the optical fiber fixing jig 7. At this time, the optical fiber fixing jig 7 is fixed on the mounting portion 6b by, for example, an ultraviolet curable adhesive 8.
[0035]
As a result, the light emitting surface of the laser diode 3 and one end of the core layer 4 of the waveguide 2 (for example, a rectangular shape of 1 × 200 μm) are positioned, and the other end of the core layer 4 (for example, a rectangular shape of 30 × 30 μm). ) And the core layer (for example, φ30 μm) of the optical fiber 1 are positioned, so that the laser beam output from the laser diode 3 can efficiently enter the core layer 1 a of the optical fiber 1.
[0036]
Next, application examples of the above optical fiber will be described.
[0037]
FIG. 4 is a configuration diagram of a rear projection television. The rear projection television is provided with a projection optical system 30 including R (red), G (green), and B (blue). The projection optical system 30 projects a color image on a screen 31 by outputting each light beam of RGB. A mirror 32 is provided in a projection direction of the projection optical system 30, and a screen 31 is provided in a reflection direction of the mirror 32.
[0038]
As shown in FIG. 5, the projection optical system 30 has a configuration in which a plurality of optical fiber tip structures (hereinafter, referred to as optical fiber tip structures 33) shown in FIG. 1 are arranged. These optical fiber tip structures 33 are assigned to any of R, G, and B, and are provided in accordance with the arrangement of R, G, and B output from the projection optical system 30.
[0039]
The laser diode 3 used in such a projection optical system 30 has an outer size of, for example, 5 mm × 0.6 mm, and the outer size of the waveguide 2 is, for example, 10 mm × 10 mm × 20 mm. The light emitting surface side of the laser diode 3 is formed in a rectangular shape of, for example, 5 × 200 μm, and the optical fiber 1 side is formed in a rectangular shape of, for example, 30 × 30 μm. In the plurality of optical fiber tip structures 33, the light emitting surface of the laser diode 3 and one end of the core layer 4 (for example, a rectangular shape of 5 × 200 μm) are positioned, and the other end of the core layer 4 (for example, a rectangular shape of 30 × 30 μm). ) And the core layer (for example, φ30 μm) of the optical fiber 1 are positioned. By integrally forming the waveguide 2 at the end of the optical fiber 1, the positioning can be easily performed. Performance can be improved.
[0040]
Further, the efficiency of incidence of the laser beam from the laser diode 3 to the core layer of the optical fiber 1 in the projection optical system 30 can be improved.
[0041]
As described above, in the embodiment, the core layer 4 and the cladding layer 5 for guiding the laser beam output from the laser diode 3 to the end face of the optical fiber 1, and one end of the core layer 4 is formed on the end face of the optical fiber 1. Since the waveguide 2 formed at a predetermined height position that can be positioned at the entrance and the other end can be positioned at the light emitting surface of the laser diode 3 is integrally formed on the end face side of the optical fiber 1, the laser diode 3 is When mounted on the mounted substrate 6, the light emitting surface of the laser diode 3 and one end of the core layer 4 can be easily positioned, and the other end of the core layer 4 and the core layer of the optical fiber 1 can be easily positioned. As a result, the optical coupling efficiency between the laser diode 3 and the optical fiber 1 can be improved.
[0042]
Further, since the light emitting surface of the laser diode 3 and one end of the core layer 4 and the other end of the core layer 4 and the core layer of the optical fiber 1 can be easily positioned, the productivity of the optical fiber tip structure is improved. it can. If this optical fiber tip structure 33 is applied to the projection optical system 30 of the rear projection television shown in FIG. 4, the productivity of the projection optical system 30 can be improved, and the optical coupling efficiency between the laser diode 3 and the optical fiber 1 can be improved. The brightness of the image projected on the screen 31 can be improved by the improvement of the image quality.
[0043]
The present invention is not limited to the above-described embodiment, and can be variously modified in an implementation stage without departing from the scope of the invention.
[0044]
Furthermore, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent features. For example, even if some components are deleted from all the components shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and the problem described in the column of the effect of the invention can be solved. In the case where the effect is obtained, a configuration from which this configuration requirement is deleted can be extracted as an invention.
[0045]
For example, the optical fiber tip structure of the present invention can be applied not only to a rear projection television but also to a portion that performs optical coupling in a field such as optical communication.
[0046]
Further, the mold body 10 is not limited to the box shape, and may be any shape such as a cylindrical shape. In any case, as long as the height position of the core shape transfer portion 13 matches the core layer of the optical fiber 1. Good.
[0047]
【The invention's effect】
As described above in detail, according to the present invention, it is possible to provide an optical fiber capable of efficiently entering a laser beam output from a semiconductor laser into an optical fiber, a method of processing the same, and a mold for an optical fiber used in the processing method.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an embodiment of an optical fiber according to the present invention.
FIG. 2 is a configuration diagram showing an embodiment of an optical fiber mold used in the optical fiber processing method according to the present invention.
FIG. 3 is a manufacturing process diagram showing one embodiment of a method for processing an optical fiber according to the present invention.
FIG. 4 is a configuration diagram of a rear projection television using one embodiment of the optical fiber according to the present invention.
FIG. 5 is a configuration diagram of a projection optical system of a rear projection television using an optical fiber according to an embodiment of the present invention.
[Explanation of symbols]
1: optical fiber 1a: optical fiber core layer 1b: optical fiber cladding layer 2: waveguide 3: laser diode 4: waveguide core layer 5: waveguide cladding layer 5a: lower cladding layer 5b: upper cladding Layer 6: substrate 6a: pedestal 6b: mounting part 7: optical fiber fixing jig 8: adhesive 10: mold body 11: optical fiber guide 12: core layer forming base 13: core shape transfer part 14: optical fiber Insertion packings 15a, 15b: fixing end 16: optical fiber holding jigs 17a, 17b: optical fiber holding jig fixing bracket 18: bolt 19: nut 20: core shape transfer groove 21: core material forming die 22: Core material injection gate 23: Core material 24: Upper cladding layer molding die 30: Projection optical system 31: Screen 32: Mirror 33: Optical fiber tip structure

Claims (5)

Optical fiber,
A core layer formed integrally with the optical fiber end face and guiding a laser beam output from a laser diode to the optical fiber end face, and a clad layer formed on the outer periphery of the core layer and the optical fiber end face. One end of the core layer is positioned at the entrance of the end face of the optical fiber, and the other end is formed at a predetermined position that can be positioned on the light emitting surface of the laser diode,
An optical fiber having a tip structure comprising: Optical fiber,
A laser diode mounted on the substrate,
A core layer integrally formed on the optical fiber end face side and guiding a laser beam output from the laser diode to the optical fiber end face, and a cladding layer formed on the outer periphery of the core layer and the optical fiber end face side. One end of the core layer is positioned at the entrance of the end face of the optical fiber, and the other end is formed at a predetermined position that can be positioned on the light emitting surface of the laser diode,
An optical fiber fixing jig for fixing the other end of the core layer to the light emitting surface of the laser diode and fixing the waveguide and the optical fiber on the substrate;
An optical fiber having a tip structure comprising: A step in which one end is positioned at the entrance of the optical fiber end face, and the other end is formed integrally with the outer periphery of the optical fiber end face side with a clad layer having a core-shaped transfer groove that can be positioned on the light emitting surface of the laser diode. ,
A step of molding a core layer by injecting a core material into the core shape transfer groove,
A method for processing an optical fiber, comprising: When the clad layer is molded on a part of the outer periphery of the optical fiber end face side, after the core layer molding step, a step of molding a clad layer on the remaining half circumference of the optical fiber end face side,
The cladding layer is formed of a two-component curable silicone resin for optics,
The optical fiber processing method according to claim 3, wherein the core layer is formed of an optical two-component curing type silicone resin having a higher refractive index than the silicone resin. A core shape transfer portion for forming a core layer for guiding a laser beam output from a laser diode; an optical fiber guide for positioning an entrance of an optical fiber end face to the core shape transfer portion; and the optical fiber end face portion for the optical fiber. An optical fiber holding jig pressed against a guide, and a mold for integrally molding a clad layer having a core shape transfer groove by the core shape transfer portion on the outer periphery of the optical fiber end face side,
A core material molding die attached to the clad layer molded using this mold, and molding the core layer by injecting a core material into the core shape transfer groove formed by the core shape transfer portion. ,
A mold for an optical fiber, comprising:

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