JP2002311260A - Plastic optical fiber, production method therefor, optical package using the same and optical wiring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plastic optical fiber, a production method therefor, an optical package using the same and an optical wiring device, by which coupling efficiency is improved and the tolerance of connection deviation is extended in an optical connection with an optical element. SOLUTION: In the plastic optical fiber 103, a top end area is made into inverse tapered shape 105 spread in the shape of inverse taper toward a top end. Further, that top end part is machined into convex surface or made into concave surface or plane and afterwards filled with materials 106 of a higher refraction factor in comparison with an optical fiber core 101 so that the top end part has convex lens operation to exhibit 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, in the connection between the plastic optical fiber and the light emitting element, further improvement in efficiency and expansion of an allowable range for connection deviation are required.

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.

In addition, in the case of an optical fiber whose tip is simply processed into a spherical surface, the tolerance of misalignment at the time of connection alignment between the light emitting element or the light receiving element and the optical fiber cannot be improved.
This is because the core diameter does not change. In addition, a fiber with a low refractive index (about 1.35), such as a plastic optical fiber made of a fluoropolymer, has a weak refracting power and can obtain a large numerical aperture by simply processing the tip with a spherical surface. difficult. In particular, the degree of improvement in the efficiency of light coupling from a light emitting element having a large spread angle to an optical fiber is small.

In view of these problems, an object of the present invention is to
Provided are a plastic optical fiber in which the tip of a plastic optical fiber is processed into a reverse tapered shape while forming the tip of the plastic optical fiber into a lens, and the tip region extends 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 tip region into a reverse taper shape by a process of heat molding the tip region and a process of putting the tip region in a softener and putting it in a mold. That is, the plastic optical fiber of the present invention has a distal end region formed in a reverse tapered shape expanding in a reverse tapered shape toward the distal end, and further processing the distal end portion into a convex shape, or a concave or planar shape. After that, the light converging function is exhibited by a method in which a material having a higher refractive index than that of the optical fiber core is filled so that the tip has a convex lens effect.

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.

In such a plastic optical fiber, with respect to the incidence from the light emitting element to the optical fiber, the coupling angle is improved by widening the acceptance angle, and the position range where high efficiency is obtained is expanded. As a result, the alignment tolerance during mounting can be improved. Further, with respect to the incidence from the optical fiber to the light receiving element, even in a plastic optical fiber having a large core diameter, the emitted light from the optical fiber can be sufficiently collected, and the coupling efficiency can be improved. Furthermore, since the lens diameter at the tip can be enlarged, the light converging diameter can be reduced to a small value, and light can be efficiently incident on a light receiving element having an extremely small light receiving area, for example, a waveguide type light receiving element.

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-to-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) optical fiber or a CYTOP (trade name) 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, the reverse taper of the tip region of the plastic optical fiber presses the tip surface of the plastic optical fiber against a heated smooth plate. The reverse taper of the tip region of the plastic optical fiber is characterized by being formed by inserting the tip region of the plastic optical fiber into a mold or sleeve having a reverse tapered hollow portion, and then heating and smoothing. It is characterized in that it is formed by pressing against a plate, or the tip of the plastic optical fiber is heated and pressed against the tip of the plastic optical fiber against a convex mold to form a concave portion. Characterized in that a lens body made of a material having a higher refractive index than that of a fiber core is formed. The tip surface of the optical fiber may be 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 may be a tip of the plastic optical fiber. Is softened with a softening agent, and then processed by placing it in a mold or sleeve having an inverted tapered hollow portion.

In these manufacturing methods, typically,
The shape of the tip of the plastic optical fiber is as follows:
It is possible to mold freely by pressing against a heated mold. By making the mold flat, concave, 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 formation of the tip region of the reverse taper shape can be formed by inserting the optical fiber into a mold or a sleeve having a trumpet-shaped hollow portion and heating the optical fiber when the optical fiber is heated. 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, since both the reverse taper and the lens are heated, the tip region of the plastic optical fiber is accurately manufactured in an arbitrary shape in combination with a mold, a sleeve, or a smooth plate. be able to. 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, for the guide means such as a guide hole for fixing the plastic optical fiber, the inversely tapered shape of the plastic optical fiber is used to make it difficult for the optical fiber to separate from the guide hole, and to provide a space between the element and the optical fiber. 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. The core 101 is used as the plastic optical fiber of this embodiment.
120 μm in diameter, 230 μm in diameter of clad 102, reinforcing layer
A fluorine-containing polymer optical fiber 103 having a total diameter of 500 μm (not shown) is used.

The fabrication of this embodiment is performed as follows. Figure
As shown in FIG. 2, after removing the reinforcing layer, the plastic optical fiber 103 was cut into a flat surface with a razor or the like using a fixing jig, and heated at a temperature in the range of 100 to 180 degrees.
The concave spherical structure 104 is formed on the tip surface of the optical fiber by pressing against a convex spherical mold 201 made of 200 μm Ni.
The diameter of the convex spherical mold 201 may be larger, and in the illustrated example, the convex spherical mold 201 has a diameter larger than the diameter of the clad 102. At this time, the tip region of the plastic optical fiber 103 naturally has an inverse tapered shape 105 due to the thermal deformation of the tip of the optical fiber. Although the length of the tip region of the inverse tapered shape 105 is not so short in light propagation, it is about 500 to 600 μm, which is about twice the diameter of the cladding 102 here.

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. 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. The refractive index of a fluorinated polymer-based optical fiber material (eg, Asahi Glass, Cytop) is about
1.35, sufficient curable resin 1 to obtain lens function
06 and the refractive index difference between the fiber optic materials (typically 0.2
From about 0.3).

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. .

The wavelength of 830 μm is measured from the other end face of the plastic optical fiber 103 whose tip is processed.
A laser beam 107 (having a wavelength suitable for light transmitted through the fluoropolymer-based plastic optical fiber 103) was incident, and the emitted 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 in the optical fiber of the flat end face, but the emitted light 108 converges in the optical fiber 103 of the present embodiment whose tip is processed. As a result, light could be efficiently incident on the light receiving element 109 1 mm away from the end face of the optical fiber.

(Second Embodiment) A plastic optical fiber 301 according to a second embodiment will be described with reference to FIGS. In the second embodiment, the same plastic optical fiber 301 as in the first embodiment is used. The fabrication was performed as follows. FIG.
After the tip region of the optical fiber 301 is inserted into a cylindrical sleeve 302 having a reverse tapered hollow portion as in the manufacturing method shown in FIG. 1, a concave spherical surface manufactured by transferring the Ni mold described in the first embodiment. The sleeve 302 and the mold 303 were heated by pressing the end face of the optical fiber against the mold 303 in the shape of a circle. As a result, as shown in FIG. 4, a convex spherical structure 401 with a bulged tip at an inverted tapered shape 402 was produced.

Since the refractive index of the tip lens body is substantially the same as that of the optical fiber core 101 as compared with the first embodiment, 1.
As low as 35. Therefore, the refracting power of the lens is weak, but the incident light 404 from the light emitting element 403 can be efficiently coupled to the plastic optical fiber 301 because of the inverted tapered shape 402 toward the tip.

In the reverse tapered region 402, the core 1
Since the diameter of 01 is increased, the effect of reducing the coupling efficiency due to misalignment between the light emitting element 403 and the plastic optical fiber 301 is also reduced.

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
Is connected to other electronic devices.

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 formed into a reverse 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 (made by Asahi Glass, trade name Lucina) using a fluoropolymer capable of transmitting light up to the 1.3 μm band, but the material is not limited.

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 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 70 is used.
1 is processed to have a convex surface. PMMA shown in FIG.
The system plastic optical fiber 701 has a core diameter of 980.
μm and a clad diameter of 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. The presence of this step is designed so that the central convex portion 702 of the optical fiber 701 does not come into contact with the mounted light emitting / receiving element.

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 has a two-stage configuration, and the light emitting surface of the light emitting element 811 and the light receiving surface of the light receiving element 812 are connected to the optical fiber 8.
01 defines the distance to the tip of the ０１01.

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.
The clad 803 is heated and pressed against a convex surface made of a fine metal hemisphere to form a concave front end portion 804. The curable resin 805 is made of an epoxy resin having a higher refractive index than that of the fluoropolymer. After dripping the curable resin onto the concave tip 604 of the plastic optical fiber 801, it is subjected to ultraviolet curing to form a convex lens on the optical fiber tip. It is.

The optical fiber guide hole is provided for the optical fiber 801.
280μmφ which can insert core wire including cladding 803
300 μm thick photosensitive resin layer 807 with holes 806 formed
To be the first layer, and 150 mm smaller than the core wire diameter of the optical fiber 801.
The second photosensitive resin layer 8 having a thickness of 200 μm and a hole 808 of μmφ
09. The plastic optical fiber 801 is fixed by inserting it into the optical fiber guide hole 806 and filling the gap around the plastic optical fiber 801 with the adhesive 810.

Even when the optical fiber 801 is mounted so that the periphery of the concave end portion 804 of the optical fiber abuts on the photosensitive resin layer 809 by the optical fiber guide hole structure of the two-stage structure, the light emitting element 811 or the light receiving element can be used. 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 second resin 809 can be controlled according to the focal length of the light converging lens.

(Sixth Embodiment) A sixth embodiment of the present invention relates to the plastic optical fiber described above,
The present invention relates to a high-speed optical wiring device formed by modularizing a 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.
In (a), 901 is a ribbon fiber in which four fibers are bundled, 902 is a plastic optical fiber of the present invention,
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. 9 (b) and 9 (c) show how the connector module and the circuit board 908 are mounted. In (b), a socket 909 is connected to a lead 91 on a substrate 908.
0 and solder 911, so that contact is obtained between the connection lead 907 of the connector module and the leaf spring 912 of the socket 909, and it is detachable.
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 / light-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 section 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, a 26-pin MDR connector according to the digital monitor interface standard for connecting a personal computer to an LCD monitor,
It is also possible to conform to standards such as EEE1394 and 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 reverse-tapered, 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 formed with 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,
There is also an effect of improving noise characteristics (SN ratio).

Further, the tolerance for the positioning error between the optical fiber, the light emitting element and the light receiving element is improved, the work of fixing the optical fiber is facilitated, and the productivity can be improved.

Further, by providing a manufacturing method capable of mass-producing such a structure for 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 diagram illustrating the operation of 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 ... Optical fiber end surface 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 ... inverted taper 106, 517, 805 ... curable resin 107 ... laser beam 108 ... outgoing light 109, 812 ... light receiving element 201 ... convex mold 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 substrate 503, 508, 704, 707 ... electrode 504 ... Element separation groove 505 ... Light emitting 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 emission Diode 705… Light extraction window 708… Wire bonding 807,809,920… Photosensitive resin layer 901… Ribbon fiber 906… Contact Lead-fixing pedestal 907,910,1002 ... connecting leads 908 ... circuit board 909 ... socket 911 ... solder 921 ... Cover 1001 ... electrical connector

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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 extends in a reverse tapered shape toward the tip, and A plastic optical fiber, wherein a lens body having a light converging function is formed. 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. A method for manufacturing a plastic optical fiber according to claim 1, wherein the reverse taper of the tip region of the plastic optical fiber is such that the tip surface of the plastic optical fiber is formed on a heated smooth plate. A method for producing a plastic optical fiber, characterized by being formed by pressing. 20. The method of manufacturing a plastic optical fiber according to claim 1, wherein the tip of the plastic optical fiber has a reverse taper, and the tip of the plastic optical fiber has a reverse tapered hollow portion. A method for producing a plastic optical fiber, comprising: inserting a molded optical fiber into a mold or a sleeve, and pressing the molded optical fiber against a heated smooth plate. 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 an inverted tapered shape after softening the tip of the plastic optical fiber 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 portion. 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.