JP2002350654A - Plastic optical fiber, manufacturing method thereof, optical package and optical wiring device using the same - Google Patents

Abstract

(57) Abstract: A plastic optical fiber with improved coupling efficiency in an optical connection with an optical element, a method of manufacturing the same, an optical package and an optical wiring device using the same. A plastic optical fiber has a forward tapered shape in which a distal end region is narrowed in a forward tapered shape toward the distal end. By processing the tip into a convex shape, or by filling the material 106 having a higher refractive index than that of the optical fiber core 101 after making the tip into a concave or flat shape, the tip has a convex lens action. To exert a light convergence function.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic optical fiber for realizing optical coupling with a light emitting element or a light receiving element with high efficiency, a method of manufacturing the same, and an optical package using the same (light emitting element and / or light receiving element). Optical interconnection module in which a plastic optical fiber is optically coupled) and an optical wiring device.

[0002]

2. Description of the Related Art In recent years, in the fields of optical communication and optical interconnection, plastic optical fibers capable of easily performing optical connection and optical mounting have been developed, and optical modules using the same have been developed. Plastic optical fibers have a core diameter of 100μ compared to quartz-based optical fibers.
Since the diameter can be increased from m to 1 mm, there is an advantage that the optical coupling efficiency with the light emitting element can be increased with a simple mounting technique.

On the other hand, in the optical coupling with the light receiving element, there is a problem that the plastic optical fiber has a large diameter, and the coupling is performed with high efficiency. In particular, in order to realize high-speed optical transmission, it is necessary to reduce the area of the light receiving element, so that there is a problem that the coupling efficiency from the plastic optical fiber to the light receiving element is reduced. Further, there is also a demand for higher efficiency in the connection between the plastic optical fiber and the light emitting element.

Therefore, a method of inserting a spherical lens or a graded index lens (GI lens) for converging light between the optical fiber and the light emitting / receiving element, or a so-called tip spherical fiber having a tip processed into a lens shape. Are disclosed in, for example, JP-A-5-107427 and JP-A-10-239538. FIG. 11 shows an example. Light from the light emitting element 5 is converged on the lens-shaped optical fiber end face 1 and is coupled to the optical fiber 2.

Further, as disclosed in Japanese Patent Application Laid-Open No. 10-111415, a method has been proposed in which a graded index optical fiber chip is bonded to the tip of a single mode optical fiber and the tip is spherically processed. . Here, as shown in FIG. 12, a GI lens piece in which only the core portion 8 protrudes from the flat cladding surface 7 by removing the portion 9 to make the core tip 10 spherical is formed by the smoothness of the optical fiber core wire 12. Adhered to the end face.

[0006]

However, the method of separately mounting the light converging lens complicates the mounting process and increases the cost because the alignment accuracy is maintained. In addition, the method of providing another optical fiber chip at the tip requires a step of bonding the optical fiber chip and a step of spherically processing the tip, which is disadvantageous in terms of yield and cost.

[0007] In the case of an optical fiber whose tip is simply processed into a spherical surface, a large improvement in the coupling efficiency between the light emitting element or the light receiving element and the optical fiber cannot be expected. This is because the core diameter does not change. Furthermore, a fiber with a low refractive index (about 1.35), such as a plastic optical fiber made of a fluoropolymer, can be obtained by simply processing the tip to a spherical surface.
Its refracting power is weak.

In view of these problems, an object of the present invention is to
Provided are a plastic optical fiber processed into a forward tapered shape in which the tip of the plastic optical fiber is formed into a lens and the tip region narrows toward the tip of the optical fiber, a method of manufacturing the same, an optical package and an optical wiring device using the same. It is in.

[0009]

In the plastic optical fiber of the present invention which achieves the above object, a lens function is provided at the tip of the optical fiber by shaping, adding a high refractive material, or a combination of both. At the same time, the above problem is solved by forming the front end region into a forward tapered shape by a process of heat-forming the front end region and a process of putting the front end region in a softener and putting it in a mold. That is, the plastic optical fiber of the present invention has a forward tapered shape in which the distal end region is narrowed in a forward taper shape toward the distal end, and the distal end is processed into a convex shape, or a concave or planar shape. Then, a material having a higher refractive index than that of the optical fiber core is filled so that the tip has a convex lens function, thereby exhibiting a light converging function.

The material having a high refractive index filled in the concave portion may be filled by being raised in a convex shape, may be filled by forming a planar end face, or may be filled by being concaved.
When the high refractive index material is filled on the planar portion,
The lens body is formed so as to protrude.
These forms may be determined according to the application.

The plastic optical fiber in the present invention refers to an optical fiber in which the entire core portion composed of a core and a clad is a polymer, or an optical fiber in which only the clad or the core is a polymer. The periphery of the core wire may be covered with a reinforcing layer or a jacket. Further, the core portion may be a step index (SI) type (refractive index step type) optical fiber or a graded index (GI) type (refractive index distribution type) optical fiber. The core diameter of the plastic optical fiber generally ranges from about 100 μm to about 1 mm.

[0012] In such a plastic optical fiber, as for the incidence from the light emitting element to the optical fiber, the numerical aperture increases, so that the coupling efficiency is improved. In addition, regarding the incidence from the optical fiber to the light receiving element, even in a plastic optical fiber having a large core diameter, the core diameter can be narrowed toward the tip, so that the emitted light from the optical fiber can be sufficiently collected, The coupling efficiency can be improved. Furthermore, by the light convergence action of the lens body provided at the tip of the optical fiber,
Optical coupling to a light receiving element having an extremely small light receiving area, for example, a waveguide light receiving element, can also be efficiently performed.

From the above, the work of fixing the plastic optical fiber of the present invention to the light emitting element or the light receiving element is facilitated, the productivity of the optical package and the optical wiring device is improved, and the cost is reduced. The distance between the optical fiber and the light emitting element or the light receiving element can be freely set,
A structure that improves the ease of mounting and the degree of freedom can be realized.
Furthermore, by improving the coupling efficiency between the plastic optical fiber of the present invention and the light emitting element or the light receiving element, it is possible to reduce the insertion loss, that is, to reduce the power consumption of the entire optical communication system or optical interconnection system, Further, the transmission speed can be increased and the signal-noise characteristics (SN ratio) can be improved.

As the material having a high refractive index for forming the lens body, curable resins such as room temperature curing type, thermosetting type, ultraviolet ray curing type, visible light curing type, electron beam curing type, etc .; There are adhesives of curable type, ultraviolet curable type, visible light curable type, electron beam curable type and the like. These materials may be determined according to the application.

The plastic optical fiber is composed of an optical fiber containing a fluorine-containing polymer, a polymethyl methacrylate optical fiber, a polystyrene optical fiber, or a polycarbonate optical fiber. Or a Teflon (trade name) based optical fiber, or a CYTOP (trade name) based optical fiber. These may be determined according to the application.

As the curable resin or the optical adhesive used in the above-mentioned embodiment, it is preferable to use a transparent resin or a synthetic resin adhesive which is excellent in transparency and has little foaming or shrinkage and expansion during curing. For the thermosetting synthetic resin adhesive, a low-temperature curable adhesive which does not cause softening of the plastic optical fiber is preferable. For a fluoropolymer-based plastic optical fiber and a polystyrene-based plastic optical fiber, 70 ° C. or less, polymethyl methacrylate The temperature is preferably 80 ° C. or less for a plastic optical fiber, and 125 ° C. or less for a polycarbonate plastic optical fiber.

Further, in the method for producing a plastic optical fiber according to the present invention, which achieves the above object, a forward taper in a tip region of the plastic optical fiber is formed by pulling and cutting the plastic optical fiber while heating the plastic optical fiber. Or the forward taper of the tip region of the plastic optical fiber is formed by pressing the tip region of the plastic optical fiber against a heated smooth plate while inserting the tip region into a mold or sleeve having a forward tapered hollow portion. Or the tip of the plastic optical fiber is formed by heating and pressing the tip of the plastic optical fiber against a convex mold to form a concave portion, and then comparing the optical fiber core to the concave portion. And forming a lens body made of a material having a high refractive index by using the plastic optical fiber. The tip surface of the plastic optical fiber is characterized by being processed by heating and pressing the tip of the plastic optical fiber against a concave mold, or the tip region of the plastic optical fiber softens the tip of the plastic optical fiber. After being softened with an agent, it is formed by processing in a mold or sleeve having a forward tapered hollow portion.

In these manufacturing methods, typically,
The tapered shape of the tip of the plastic optical fiber can be obtained by a method of pulling and cutting the plastic optical fiber in a heated state or a method of heating and molding in a cylindrical mold. By making the mold flat, concave, or convex, any tip shape can be formed. The spherical or aspherical mold diameter is preferably equal to or larger than the core diameter of the plastic optical fiber. At the same time, the forward tapered tip region can also be formed by inserting the optical fiber into a mold or sleeve having a funnel-shaped hollow portion and pressing the optical fiber during heating. Of course, these steps may be different steps.

A resin having a higher refractive index than that of the core material is adhered to the processed end portion, particularly, a flat or concaved front end surface.
The resin is adhered so as to be raised, and is adhered so as to fill the concave front end surface. At that time, the upper surface of the resin only needs to have a curvature capable of exerting a convex lens effect.
The resin tip may be adhered until it becomes flat, or may be adhered until it rises further. Of course, if the light converging power may be low, the resin upper surface may be concave like a meniscus lens.

The method for producing a plastic optical fiber according to the present invention can be applied to plastic optical fibers of any size. In these manufacturing methods, typically, both the forward taper and the tip lens are heated, so that the tip region of the plastic optical fiber can be accurately formed into an arbitrary shape in combination with a mold, a sleeve, or a smooth plate. can do. Therefore, it is possible to omit a precision polishing process, a chemical treatment process, or a process such as a separate alignment with a minute lens.

Further, the optical package using the plastic optical fiber of the present invention, which achieves the above object, is characterized in that the plastic optical fiber is optically controlled by a light emitting element, a light receiving element, or both a light emitting element and a light receiving element and a guide means. It is characterized in that it is combined in a typical manner.

Here, as for the guide means such as a guide hole for fixing the plastic optical fiber, the forward tapered shape of the plastic optical fiber is used to make it difficult for the optical fiber to be separated from the guide hole, so that the distance between the element and the optical fiber is reduced. Or can be fixed.

For the light emitting element combined with the plastic optical fiber, a surface emitting laser, a light emitting diode, a Fabry-Perot type laser or a DF is used in accordance with the transmission speed and the used wavelength band of the transmission system and the interconnection system.
B (distributed feedback) or DBR (distributed
An edge-emitting laser which is a Bragg reflector laser is used. According to the present invention, since the acceptance angle of the plastic optical fiber can be designed according to the light emitting element, high efficiency coupling to various light sources is possible.

As for the light receiving element, a pin type photodiode, a metal-insulating layer-metal type (MSM type) photodetector, and the like include a surface light receiving type and a waveguide type. In particular, to perform high-speed detection, it is necessary to reduce the light receiving area.
The light focusing effect of the plastic optical fiber according to the present invention can be effectively utilized for such a light receiving element.

The gap between the plastic optical fiber and the light emitting element or the light receiving element may be filled with air or an inert gas, or may be filled with a resin or an adhesive.

At this time, when the space between the light emitting / receiving element and the end face of the optical fiber is filled with an inert gas such as air or nitrogen gas, the surrounding refractive index is almost 1, and the lens body (core or core) at the end of the optical fiber is filled. It is sufficient if it is formed of a clad or a resin) that produces a convex lens effect. On the other hand, when a curable resin or an optical adhesive or the like is filled between the light emitting / receiving element and the end face of the optical fiber, in consideration of the magnitude relationship between the refractive index of the optical fiber and the curable resin or the optical adhesive, The end face of the optical fiber is made convex or concave.

Particularly, in the case of an optical fiber having a low refractive index of about 1.35, such as a fluorinated polymer plastic optical fiber, the periphery of the convex optical fiber end face is filled with resin to obtain a convex lens effect. Then, it is necessary to select a resin having a lower refractive index. However, there is hardly any resin having such a low refractive index, and even if realized, the refractive index difference from the optical fiber is too small,
Only a convex lens with extremely weak refracting power is realized. Therefore, in the present invention, the end surface of the plastic optical fiber is formed into a concave shape, and the concave surface is immersed in a curable resin or an optical adhesive having a relatively high refractive index, so that the resin side exhibits a light converging function as a convex lens. Let it. In this case, as compared with a method in which the end surface of the optical fiber is a convex lens, the center portion of the end surface of the optical fiber is recessed, so that even when the end surface of the optical fiber is brought close to the light emitting or light receiving element, the optical fiber is easily contacted without contact. It can be implemented.

In any of the above cases, the optical fiber itself can exhibit a convex lens function having convergence without mounting a separate lens after positioning.

Further, the light emitting and light receiving elements may be formed in a plurality of arrays, and correspondingly, plastic optical fibers may be formed in an array. The plurality of light-emitting / light-receiving elements may be only light-emitting elements, only light-receiving elements, or a combination of light-emitting elements and light-receiving elements.

Further, an optical wiring device of the present invention for achieving the above object is an optical wiring device including an optical package using the above plastic optical fiber, wherein the light emitting element or the light receiving element is drivable. And an electrical connection to a drive electronic circuit, and is mounted on a mounting substrate.

More specifically, the mounting board is configured to be mounted on a board in an electronic device via a connection lead, and signals are transmitted and received between the boards by light. The mounting board is housed in the electrical connector,
An electrical connection to the driving electronic circuit is made by a connection pin for a detachable connector, and transmission and reception of signals between electronic devices are performed by light.

[0032]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) A plastic optical fiber according to a first embodiment of the present invention is shown in a sectional view of FIG.
As the plastic optical fiber of this embodiment, the core 10
A fluoropolymer-based plastic optical fiber 103 having a diameter of 120 μm, a diameter of the cladding 102 of 230 μm, and a total diameter of 500 μm including a reinforcing layer (not shown) is used.

The fabrication of this embodiment is performed as follows. Figure
As shown in FIG. 2, the plastic optical fiber 103 is cut into a forward tapered shape 105 by removing the reinforcing layer, fixing both sides to a fixing jig, heating the surroundings with a heater 202 and pulling it. Next, a concave spherical structure 104 is formed on the distal end surface of the optical fiber by pressing against a convex spherical mold 201 made of Ni having a diameter of 200 μm and heated in the range of 100 ° C. to 180 ° C. It is not preferable that the length of the front end region of the forward tapered shape 105 is too short because light propagation loss occurs. In this example, 400 to 600, which is about twice the diameter of the clad 102,
It is about μm.

Subsequently, as shown in FIG. 1, the core 10 of the plastic optical fiber 103 is
A curable resin 106 having a refractive index higher than one material is filled. By adjusting the filling amount, the lens body at the tip of the optical fiber can be controlled from a plano-convex lens to a biconvex lens or a meniscus lens. In this embodiment, a biconvex lens is used. Of course, the material of the cladding 102 has a lower refractive index than the material of the core 101, so that the refractive index of the curable resin 106 is larger than the refractive index of the cladding 102. The refractive index of the filled curable resin 106 can be selected in the range of about 1.4 to 1.7. In the present example, the one with 1.54 was used. Fluoropolymer-based optical fiber material (eg, Cytop, trade name, manufactured by Asahi Glass)
(CYTOP)) has a refractive index of about 1.35, and a refractive index difference (typically about 0.2 to 0.3) between the curable resin 106 and the optical fiber material sufficient to obtain a lens function is obtained.

The curable resin 106 is classified into a room-temperature curing type, a thermosetting type, and a photo-curing type. In the present embodiment, since the softening temperature of the fluorine-containing polymer optical fiber 103 is relatively low, the room-temperature curing type is used in this embodiment. used. Of course, a thermosetting resin having a curing temperature lower than the softening temperature of the plastic optical fiber 103 can be cured by heating. In addition, a photo-curing type of ultraviolet, visible light or electron beam curing may be used. As long as it is a curable resin, an adhesive can of course be used. In this case, an optical adhesive that is transparent to the wavelength used and is optically stable (a property that does not cause color change or scattering due to heat or temperature) is more preferable. .

A laser beam 107 having a wavelength of 830 μm (a wavelength suitable for light transmitted by the fluoropolymer-based plastic optical fiber 103) is incident from the other end face of the plastic optical fiber 103 subjected to the above-mentioned tip processing. The outgoing light 108 from the processed optical fiber tip was observed. As a comparison, the same was performed with a plastic optical fiber having a flat end face polished after cutting the tip with a razor. As a result, the emitted light spreads out in the optical fiber of the flat end face, but the optical fiber 1 of this embodiment having the tip processed.
In 03, the mode conversion gradually progressed due to the forward tapered shape 105 toward the tip, and the emitted light 108 converged. As a result, it was possible to efficiently make light incident on the light receiving element 109 separated from the end face of the optical fiber by about 500 μm.

(Second Embodiment) A second embodiment will be described with reference to FIGS.
The plastic optical fiber 301 of the embodiment will be described.
In the second embodiment, the same plastic optical fiber 301 as in the first embodiment is used.

The fabrication was performed as follows. As shown in FIG. 3, after inserting the distal end region of the optical fiber 301 into a cylindrical sleeve 302 having a forward tapered hollow portion,
The end face of the optical fiber was pressed against the concave spherical mold 303 produced by transferring the Ni mold described in the first embodiment, and the sleeve 302 and the mold 303 were heated. As a result, as shown in FIG.
Was produced.

As compared with the first embodiment, the refractive index of the tip lens body is substantially as low as about 1.35 because it is substantially the same as that of the optical fiber core. Therefore, the refracting power of the lens is weak, but the numerical aperture increases due to the taper.
3 can be efficiently coupled to the plastic optical fiber 301.

As the plastic optical fiber 301,
In addition to the fluorinated polymer-based optical fiber, those using polymethyl methacrylate (PMMA), those using polystyrene, polycarbonate, and the like can also be used.
The present embodiment can be manufactured by controlling the heating temperature according to the material. The sleeve 302 and the concave spherical mold 3
The form 03 may be, for example, a form in which the sleeve is in the form of a split sleeve and one half-cylindrical split sleeve and a concave spherical mold are integrated.

Third Embodiment An optical package according to a third embodiment of the present invention will be described with reference to FIGS.

In this embodiment, a surface emitting laser 501 in which four resonator layers each including an active layer are arranged at a pitch of 750 μm and sandwiched between DBR mirrors is bonded to a mounting substrate 502 via a common electrode 503. Have been. In FIG.
An element isolation groove of each surface emitting laser is indicated by 504, and a portion corresponding to a light emitting point is indicated by 505. As electric wiring for driving the surface emitting laser 501, a wiring 506 for a common electrode and a wiring 507 for independent driving are formed on a mounting substrate 502. The wiring 507 for independent driving is connected to the independent electrode 508 for driving the surface emitting laser. A driver IC 509 for driving a surface-emitting laser, which is connected to a wiring 507 for independent driving, is flip-chip mounted on the same mounting substrate 502. The driver IC 509 has a wiring 510
To another electronic device (not shown).

The plastic optical fiber 511 is provided with a fixing jig 512 having a V-groove formed by a plastic mold.
Is sandwiched by the flat jig 513 and the adhesive 5
14 fixed. The V-groove enables the periodic interval and the center position of the plastic optical fiber 511 to be aligned. The tip of the plastic optical fiber protrudes from the surface formed by the fixing jigs 512 and 513 as shown in FIG. 5, and in this embodiment, the protruding amount is 500 μm.

The four plastic optical fibers 511 are
After the adhesive is fixed by using the fixing jigs 512 and 513, it is cut at once by a razor, and the end face is flattened by polishing. Thereafter, the tip of the plastic optical fiber 511 was processed into a concave spherical structure 515 and the tip region was processed into a forward taper by the method described in the first embodiment.

Such a plastic optical fiber 511
Can be set in the guide hole 516 for inserting an optical fiber.
After injecting 17, it is inserted and fixed here. Here, by heating at 60 ° C. to cure the curable resin 517, the convex lens function of the end face of the optical fiber 511 is exhibited.

As shown in FIG. 6, the plastic optical fiber 511 has a flat region around the concave spherical structure 515 at the tip.
It is fixed at a position where it comes into contact with the element surface. Therefore, the end face of the optical fiber does not directly hit the crystal surface of the surface emitting laser 501, and does not damage the crystal surface.

On the receiving side at the other end of the plastic optical fiber 511, a coupling form is produced by using a surface type photodiode similarly to the surface emitting laser. In the present embodiment, an example is shown in which the number of arrays of the surface emitting lasers, the surface type photodiodes, and the optical fibers is four, but the number is of course not limited. Four or more of them may be used, or only one set of a surface emitting laser, a surface type photodiode, and one optical fiber may be used.

The plastic optical fiber 511 used in this embodiment is an optical fiber using a fluoropolymer capable of transmitting up to the 1.3 μm band (Lucina, trade name, manufactured by Asahi Glass).
However, there is no restriction on the material.

The diameter of the guide hole 516 and the V of the fixing jig 512
The shape of the groove may be designed according to the fiber diameter. The guide hole 516 is preferably, for example, a hole formed in a Si substrate by etching, a hole formed in a resin by etching, or a hole formed by patterning a thick film resist. Although a thermosetting resin is used as the curable resin 517, various curable resins and optical adhesives may be used as long as the resin has a higher refractive index than the optical fiber core.

The laser drive circuit 509 and the receiving amplifier circuit chip (used on the receiving side) are sequentially bonded by a flip chip bonder. The mounting body may be one in which only the surface emitting laser is integrated on the transmission side, one in which only the surface type photodiode is integrated on the receiving side, or one in which both of the transmitting and receiving devices are provided. When the transmitting device and the receiving device are separated, one-way transmission is performed. On the other hand, when the transmitting device and the receiving device are housed in one module, bidirectional transmission is possible.

(Fourth Embodiment) An optical package according to a fourth embodiment of the present invention will be described with reference to FIG. In this embodiment, a polymetal methacrylate (PMMA) -based optical fiber 7 is used.
01 is formed in a convex shape. PMM shown in FIG.
The diameter of the A-type plastic optical fiber 701 is 98 core diameter.
The thickness is 0 μm, the cladding diameter is 1 mm, and the tip is heated and pressed against a concave metal mold to be shaped as a convex tip 702 (see the second embodiment). A flat step is formed around the optical fiber 701 by the periphery of the concave spherical mold. Due to the presence of this step, the optical fiber 701
The center convex portion 702 is designed so as not to contact the light emitting / receiving element mounted thereon.

The PMMA-based optical fiber 701 has a core refractive index of about 1.5 to 1.51, which is higher than that of the fluoropolymer-based optical fiber.
The gap with the light receiving element is sealed with nitrogen. The optical fiber 701 is fixed to the guide hole 709 by using an ultraviolet-curing adhesive to solidify the periphery. Of course, as long as the resin has a low refractive index of about 1.35, a curable resin for sealing the tip of the optical fiber may be used.

The light emitting device of this embodiment has an oscillation wavelength of 65
A red light emitting diode 703 of 0 nm (a wavelength suitable for light transmitted through the PMMA optical fiber 701) is used. On the surface of the light emitting diode 703, p
An electrode / electric wiring and an electrode pad 704 are formed. A light extraction window 705 is formed at a position corresponding to the light emitting point of the p electrode. The electrode pad 707 and the p-electrode 7 on the mounting substrate 706 electrically connected to the IC 710
04 are wired by wire bonding 708. This wiring may use a flexible wiring board or the like.

The optical fiber guide hole 709 is formed after forming the light emitting diode 703 and the p electrode on the GaAs substrate.
Before cutting into chips, they are collectively formed on the surface.
Therefore, there is no process such as photolithography after the chip of the light emitting diode 703 is mounted on the mounting substrate 706, but only surface mounting by batch reflow and wiring by wire bonding.

In this embodiment, since the light emitting diode is driven, the speed is inferior to that of the surface emitting laser according to the third embodiment. However, in the structure of the present embodiment, the number of arrays is small and 100 to 2 because the number of process steps is reduced and the manufacturing cost can be reduced and the yield can be improved.
It is suitable for transmission of about 00 Mbps. The receiving side is pi
An n-type photodiode is mounted in an arrangement equivalent to the light emitting diode 703. Here, the difference from the above configuration is that an amplifier IC is mounted instead of the driving IC 710.

(Fifth Embodiment) An optical package according to a fifth embodiment of the present invention will be described with reference to FIG. In this embodiment,
The optical fiber guide hole is formed in a two-stage configuration, and the light emitting element 811 is formed.
This defines the distance between the light emitting surface of the optical fiber 801 and the light receiving surface of the light receiving element 812 and the tip of the optical fiber 801.

This will be described with reference to FIG. The plastic optical fiber 801 has a core 8 made of a fluoropolymer.
02 and a cladding 803, and after removing a reinforcing layer (not shown) made of acrylic, a core 802 is formed.
And the clad 803 are heated and pressed against a mold whose inner periphery is a tapered cylinder and whose bottom is a convex surface made of a fine metal hemisphere, thereby forming a concave tip 804. The curable resin 805 is made of an epoxy resin having a higher refractive index than that of the fluoropolymer, and is dropped on the concave end portion 804 of the plastic optical fiber 801 and then cured by ultraviolet rays to form a convex lens on the optical fiber end portion. It is.

The optical fiber guide hole is provided for the optical fiber 801.
A light-emitting element 811 and a light-receiving element 812 are formed by forming a photosensitive resin layer 807 having a hole 806 with a diameter of 150 μm
A 200 μm thick photosensitive resin layer 809 having a 280 μmφ hole 808 into which a core including the cladding 803 of the optical fiber 801 can be inserted is formed as a first layer with a thickness of 200 μm from the top.
The second layer. To fix the plastic optical fiber 801, insert it into the optical fiber guide hole 808 and remove all the gaps around the plastic optical fiber 801 with the adhesive 8.
It is filled with ten.

Even when the optical fiber guide hole structure of the two-stage structure is used so that the periphery of the concave end portion 804 of the optical fiber abuts on the photosensitive resin layer 807, the optical fiber 801 can be used as the light emitting element 811 or the light receiving element. 812
It does not cause damage by colliding with. The curable resin 805 filled in the concave portion 804 at the tip of the optical fiber serves as a light convergence lens, and the light coupling with the light emitting element 811 or the light receiving element 812 immediately below is efficiently performed. in this way,
The thickness of the first resin layer 807 can be controlled according to the focal length of the light converging lens.

(Sixth Embodiment) The sixth embodiment according to the present invention relates to a high-speed optical wiring device formed by modularizing the above-mentioned plastic optical fiber and light-emitting / light-receiving element mounting body. .

FIG. 9 shows an optical wiring device or connector module using an optical package in which a light emitting element or a light receiving element and an optical fiber are fixed by an optical fiber guide hole made of a thick film photosensitive resin as in the above-described embodiment. Is shown. FIG.
9A, reference numeral 901 denotes a ribbon fiber in which four fibers are bundled, 902 denotes a plastic optical fiber of the present invention (the tip region is not drawn in a forward tapered shape in FIG. 9),
Reference numeral 903 denotes an optical fiber fixing jig, and reference numeral 904 denotes an optical fiber fixing jig which covers the whole to increase the fixing strength of the optical fiber 902.
Although reference numeral 905 denotes a mounting substrate, peripheral circuits are formed at the same time, and chip resistors and capacitors are integrated. Reference numeral 906 denotes a pedestal for fixing the connection lead 907, which is adhered to the back surface of the mounting board 905 to form the mounting board 905.
Are connected to the tops of the leads 907 by wire bonding. Fiber 902 and mounting substrate 90
The fixation between 5 and 5 is performed last after performing the wire bonding. The connection between the connection lead 907 and the mounting board 905 may be performed by flip-chip mounting by forming a through hole in the mounting board 905.

On the other hand, FIGS. 9B and 9C show a mounting form of the connector module and the circuit board 908. FIG.
In (b), the socket 909 is fixed on the substrate 908 with the lead 910 and the solder 911, so that the connection lead 907 of the connector module and the leaf spring 912 of the socket 909 can be in contact with each other. It is possible. In (c), the connection leads 907 are directly soldered (911) to the circuit board 908.

With such a configuration, it is possible to provide an optical wiring device in a case where high-speed signals are transmitted between boards. Further, an optical package in which the plastic optical fiber of this embodiment and the light emitting / receiving element are mounted can be mounted on a motherboard, and data can be transmitted between the devices via an optical fiber coupler.

Further, the bonding between the mounting substrate 905 and the optical fiber fixing jig 903 is not performed, and the thick film photosensitive resin 920 is not used.
The optical fiber guide hole may be detachable. In that case, it is sufficient to provide a nail or the like on the outer frame of the optical fiber fixing jig 903 to produce a detachable mechanism. In addition,
921 is a cover.

Such an optical wiring device has 1 Gbps per channel.
This is effective for high-speed transmission exceeding s and transmission / wiring systems in which electromagnetic radiation noise is a problem.

(Seventh Embodiment) In a seventh embodiment of the present invention, an optical package in which a plastic optical fiber and a light emitting / receiving element are mounted as in the sixth embodiment is directly mounted on a motherboard. Instead, as shown in FIG. 10, it is housed in an electric connector 1001 so that it can be connected to and detached from an interface unit of an electronic device such as a personal computer, a monitor, a printer, a digital camera, a digital video camera, etc. via an electric connection lead 1002. I have to. The electrical connector 1001 can be manufactured according to the required device standard. For example, it is possible to use a 26-pin MDR connector according to the standard of a digital monitor interface for connecting a personal computer and a liquid crystal monitor, or to conform to a standard such as IEEE1394 or USB. Further, the present invention can be applied to an internal connection between a scanner unit and a photosensitive unit of a digital copier.

By using the optical wiring device of the present invention to connect these electronic devices, 1 Gbps per channel can be achieved.
At about 2.5 Gbps, signal transmission of 4 to 5 channels becomes possible over 50 m. Thus, electric cables can be used in place of the limited high-speed video transmission. In addition, since the optical connection is used, there is no electromagnetic radiation noise generated from the transmission line, and it is possible to reduce noise measures particularly in high-speed digital transmission.

[0069]

According to the present invention, the following effects are expected. In the plastic optical fiber of the present invention, in order to increase the optical coupling efficiency, the distal end region of the optical fiber is tapered forward, and the optical fiber distal end is filled with a high refractive index resin with a concave surface, or the optical fiber distal end is made a convex surface. Thus, the light converging function is provided at the tip. Thus, the insertion loss associated with the optical connection can be reduced, and as a result, an optical package and an optical wiring device with low power consumption can be provided. Furthermore, since the reflected return light from the optical fiber connection point can be suppressed, the signal
There is also an effect of improving noise characteristics (SN ratio).

Further, by providing a manufacturing method capable of mass-producing a structure for such highly efficient mounting,
An optical wiring device that can be reduced in cost can be realized. Therefore, in the area of electronic equipment that handles high-speed digital signals, or in the signal connection between electronic equipment, it is possible to transmit signals of about 2.5 Gbps in a limited area of electric transmission, that is, about 50 Gbps or more, Easy transmission, etc.
It can be performed without any special measures against electromagnetic noise.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a plastic optical fiber according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a method for manufacturing a plastic optical fiber according to a first embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a method for manufacturing a plastic optical fiber according to a second embodiment of the present invention.

FIG. 4 is a view illustrating a plastic optical fiber according to a second embodiment of the present invention.

FIG. 5 is a perspective view illustrating an optical package including a plastic optical fiber and a light emitting element or a light receiving element according to a third embodiment of the present invention.

FIG. 6 is a sectional view showing an embodiment in which a plastic optical fiber according to a third embodiment of the present invention is mounted on a light emitting element or a light receiving element.

FIG. 7 is a perspective view illustrating an optical package including a plastic optical fiber and a light emitting element or a light receiving element according to a fourth embodiment of the present invention.

FIG. 8 is a sectional view showing an embodiment in which a plastic optical fiber according to a fifth embodiment of the present invention is mounted on a light emitting element or a light receiving element.

FIG. 9 is a diagram illustrating an optical package including a plastic optical fiber and a light-emitting element or a light-receiving element according to a sixth embodiment of the present invention and an optical wiring device using the same.

FIG. 10 is a diagram illustrating an optical wiring device using an optical package including a plastic optical fiber and a light emitting element or a light receiving element according to a seventh embodiment of the present invention.

FIG. 11 is a view showing a conventional example regarding processing of a front end lens of an optical fiber.

FIG. 12 is a diagram showing another conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... End face of optical fiber 2 ... Optical fiber 5 ... Light emitting element 7 ... Flat clad surface 8 ... Core part 10 ... Spherical core tip 12 ... Optical fiber core wire 101,802 ... Core 102,803 ... Clad 103,301,511 , 701, 801, 902, 1003 ... plastic optical fibers 104, 515, 804 ... concave structure 105, 402 ... forward taper 106, 517, 805 ... curable resin 107 ... laser beam 108 ... emission light 109, 812 ... light receiving element 201 ... Convex mold 202 ... Header 302 ... Sleeve 303 ... Concave mold 401,702 ... Convex structure 403,811 ... Light emitting element 404 ... Incident light 501 ... Surface emitting laser 502,706,905 ... Mounting board 503,508,704,707 … Electrode 504… Element separation groove 505… Emission point 506, 507, 510… Electrode wiring 509, 710… IC 512, 513, 903, 904… Fixing jig 514… Adhesive 516, 709, 806, 808… Optical fiber guide Hole 703: Light-emitting diode 705: Light extraction window 708: Wire bonding 807, 809, 920: Photosensitive resin layer 901: Ribbon fiber Bar 906 ... connection leads fixed pedestal 907,910,1002 ... connecting leads 908 ... circuit board 909 ... socket 911 ... solder 921 ... Cover 1001 ... electrical connector

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01S 5/183 H01L 31/02 CF term (Reference) 2H037 AA01 BA03 BA12 CA02 CA07 CA08 CA12 CA20 2H050 AC87 AC90 5F041 CA12 CB22 EE03 FF14 5F073 AB02 AB17 AB28 BA02 EA29 FA07 5F088 BB01 EA02 JA05 JA14

Claims (34)

[Claims] 1. A plastic optical fiber in which at least one of a core and a clad is made of a polymer material, wherein the tip region of the plastic optical fiber narrows in a forward tapered shape toward the tip, and And a lens body having a light converging function. 2. The plastic optical fiber according to claim 1, wherein a lens body made of a material having a higher refractive index than the optical fiber core is formed at the tip of the plastic optical fiber. 3. The plastic optical fiber according to claim 1, wherein the tip end surface is concavely concave, and the concave portion is filled with a material having a higher refractive index than the optical fiber core to form a lens body. 3. The plastic optical fiber according to claim 2, wherein: 4. The plastic optical fiber according to claim 3, wherein said high refractive index material is raised in a convex shape. 5. The plastic optical fiber according to claim 3, wherein said high refractive index material forms a flat end face. 6. The plastic optical fiber according to claim 3, wherein said high refractive index material is concavely concave. 7. The plastic optical fiber has a flat distal end surface, and a lens body made of a material having a higher refractive index than that of the optical fiber core is formed in a convex shape on the flat surface portion. 3. The plastic optical fiber according to claim 2, wherein 8. The plastic optical fiber according to claim 1, wherein the tip of the plastic optical fiber is made of the same material as the plastic optical fiber wire and protrudes into a convex lens shape. 9. The plastic optical fiber according to claim 1, wherein said lens body is made of a curable resin. 10. The lens body according to claim 1, wherein said lens body is made of a curable resin of a room temperature curing type, a thermosetting type, an ultraviolet ray curing type, a visible light curing type, or an electron beam curing type. A plastic optical fiber according to any one of the above. 11. The plastic optical fiber according to claim 1, wherein said lens body is made of an adhesive. 12. The lens body according to claim 1, wherein said lens body is made of an adhesive of room temperature curing type, thermosetting type, ultraviolet ray curing type, visible light curing type, or electron beam curing type.
A plastic optical fiber according to any one of the above. 13. The plastic optical fiber according to claim 1, wherein said plastic optical fiber comprises an optical fiber containing a fluoropolymer. 14. The plastic optical fiber according to claim 1, wherein said plastic optical fiber comprises a polymethyl methacrylate-based optical fiber. 15. The plastic optical fiber according to claim 1, wherein said plastic optical fiber comprises a polystyrene-based optical fiber. 16. A plastic optical fiber according to claim 1, wherein said plastic optical fiber comprises a polycarbonate optical fiber. 17. The plastic optical fiber according to claim 1, wherein said plastic optical fiber comprises a Teflon (registered trademark) optical fiber. 18. The plastic optical fiber according to claim 1, wherein said plastic optical fiber comprises a Cytop optical fiber. 19. The method of manufacturing a plastic optical fiber according to claim 1, wherein the forward taper in the tip region of the plastic optical fiber is formed by pulling and cutting the plastic optical fiber while heating the plastic optical fiber. A method for producing a plastic optical fiber. 20. The method of manufacturing a plastic optical fiber according to claim 1, wherein the forward taper of the distal end region of the plastic optical fiber is a forward tapered hollow portion. A method for producing a plastic optical fiber, wherein the plastic optical fiber is formed by being pressed into a heated smooth plate while being inserted into a mold or a sleeve having the following. 21. The method of manufacturing a plastic optical fiber according to claim 3, wherein the tip of said plastic optical fiber is heated and pressed against a convex mold to form a concave portion. A method for manufacturing a plastic optical fiber, comprising forming a lens body made of a material having a higher refractive index than an optical fiber core on a concave surface portion. 22. The method of manufacturing a plastic optical fiber according to claim 8, wherein a tip of the plastic optical fiber is processed by heating and pressing the tip of the plastic optical fiber against a concave mold. Characteristic method for producing plastic optical fiber. 23. The method of manufacturing a plastic optical fiber according to claim 1, wherein the tip region of the plastic optical fiber has a forward tapered shape after the tip of the plastic optical fiber is softened with a softener. A method for producing a plastic optical fiber, characterized by being formed by processing in a mold or sleeve having a hollow part. 24. A plastic optical fiber according to claim 1, wherein the plastic optical fiber is optically coupled to a light emitting element, a light receiving element, or both the light emitting element and the light receiving element by guide means. Optical package using plastic optical fiber. 25. The optical package according to claim 24, wherein the light emitting element is a surface emitting laser, a light emitting diode, or an edge emitting laser. 26. The optical package according to claim 24, wherein the light receiving element is a surface type photodiode, a waveguide type photodiode, or a metal-insulating layer-metal type photodetector. 27. The plastic optical fiber according to claim 24, wherein a gap between the plastic optical fiber and a light emitting element or a light receiving element is filled with air or an inert gas. The optical package used. 28. An optical package using a plastic optical fiber according to claim 24, wherein a resin is filled in a gap between said plastic optical fiber and a light emitting element or a light receiving element. body. 29. The plastic optical fiber according to claim 29, wherein the tip end surface is processed into a concave shape, and the resin to be filled is a resin having a higher refractive index than the core of the plastic optical fiber. Item 29. An optical package using the plastic optical fiber according to item 28. 30. The plastic optical fiber according to claim 30, wherein a tip surface of the plastic optical fiber is processed into a convex shape, and the resin to be filled is a resin having a lower refractive index than a core of the plastic optical fiber. Item 29. An optical package using the plastic optical fiber according to item 28. 31. A plastic according to claim 24, wherein a plurality of said plastic optical fibers are arrayed, and a light emitting element and a light receiving element are also arrayed correspondingly. An optical package using an optical fiber. 32. An optical wiring device including an optical package using a plastic optical fiber according to claim 24, wherein said light emitting element or light receiving element is driven by a driving electronic device. An optical wiring device having an electrical connection to a circuit and mounted on a mounting substrate. 33. The optical device according to claim 32, wherein the mounting board is configured to be mounted on a board in an electronic device via a connection lead, and transmits and receives signals between the boards by light. Wiring device. 34. The mounting board is housed in an electric connector, and is electrically connected to the driving electronic circuit by a connection pin for a detachable connector. 33. The method according to claim 32, wherein the step is performed by light.
An optical wiring device as described in the above.