JP2000047052A - Manufacture of branch plastic optical fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a branch plastic optical fiber without need to position it and without an interface. SOLUTION: After liquid core material 28a is injected into a clad that the clad 21 of a branch part 20 is connected to the clad 25, 26, 27 of the optical fibers 22, 23, 24 to be integrated, by hardening it with ultraviolet irradiation or heating, the interface between the core 28 of the branch part 20 and the core 28 of the optical fibers 22, 23, 24 are eliminated, and moreover, the positioning between the core 28 of the branch part 20 and the core 28 of the optical fibers 22, 23, 24 becomes unnecessary.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a branched plastic optical fiber.

[0002]

2. Description of the Related Art FIG. 4A is a left side view of a branch portion used in a conventional branch plastic optical fiber.
4B is a plan sectional view, and FIG. 4C is a right side view. FIG. 5A is a left side view of a branch portion used in another conventional branched plastic optical fiber, FIG. 5B is a plan sectional view, and FIG. 5C is a right side view.

In FIGS. 4 and 5, reference numerals 11 and 12 denote cores, and reference numerals 13 and 14 denote claddings.

As shown in FIGS. 4 and 5, Y-shaped and V-shaped branch portions are used for branching optical fibers, and the connection is made by connecting optical fibers to these branch portions.

[0005]

However, it is difficult to align the core of the branch portion with the core of the optical fiber, and the connection portion has special features such as connection of the core by fusion or optical connection by a refractive index matching material. Unless the method is applied, there is a problem that an interface exists and causes a loss.

Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide a method of manufacturing a branched plastic optical fiber which does not require alignment and has no interface.

[0007]

In order to achieve the above object, a method of manufacturing a branched plastic optical fiber according to the present invention comprises:
Manufacture of a branched plastic optical fiber by connecting a branch core made of a transparent resin with a cladding made of a transparent resin having a lower refractive index than the branch core and an optical fiber core to manufacture a branched plastic optical fiber In the method,
Form the cladding of the branch and the cladding of the optical fiber,
After connecting and integrating the two claddings, a liquid core is injected into the cladding and then cured.

[0008] In addition to the above structure, the method for manufacturing a branched plastic optical fiber of the present invention is characterized in that the cladding of the optical fiber is made of polytetrafluoroethylene, tetrafluoroethylene / tetrafluoroethylene.
Hexafluoropropylene copolymer, ethylene / tetrafluoroethylene copolymer, tetrafluoroethylene /
Any one of a vinylidene fluorolide copolymer and a tetrafluoroethylene / hexafluoropropylene / vinylidene fluorolide copolymer, wherein the cladding of the branch portion is a tetrafluoroethylene / hexafluoropropylene copolymer, a tetrafluoroethylene / perfluoro It is preferably one of alkyl vinyl ether copolymers.

In addition to the above construction, in the method of manufacturing a branched plastic optical fiber according to the present invention, it is preferable that the core of the optical fiber is made of a thermosetting silicone resin or an ultraviolet curing silicone resin.

[0010] In addition to the above structure, in the method of manufacturing a branched plastic optical fiber of the present invention, it is preferable that the cladding of the branch portion is formed by injection molding.

According to the present invention, a liquid core is injected into a clad in which the cladding of the branch portion and the cladding of the optical fiber are connected and integrated, and then cured.
There is no interface between the core of the branching part and the core of the optical fiber, and the alignment of the core of the branching part with the core of the optical fiber becomes unnecessary.

[0012]

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

FIG. 1 is a plan sectional view showing an embodiment of a branched plastic optical fiber to which the method for manufacturing a branched plastic optical fiber of the present invention is applied.

A method for manufacturing a branched plastic optical fiber according to the present invention will be described.

The cladding 21 of the branch portion 20 is formed by injection molding using a mold (not shown). Optical fiber 22,
23, 24 cladding (tubular) 25, 26, 27
(Eg, extrusion molding).

The claddings 21 of the optical fibers 22, 23 and 24 are connected to the cladding 21 of the branching section 20 and integrated.

After the liquid core material 28a is injected into the claddings 21, 25, 26, and 27, the core material 28a is irradiated with ultraviolet rays (or heated) to be hardened to form the core 28, thereby branching. A plastic optical fiber 29 is obtained.

The cladding 2 of the optical fibers 22, 23, 24
5, 26 and 27 are polytetrafluoroethylene, tetrafluoroethylene / hexafluoropropylene copolymer, ethylene / tetrafluoroethylene copolymer, tetrafluoroethylene / vinylidene fluoride copolymer, tetrafluoroethylene / hexafluoropropylene / Vinylidene fluoride copolymer.

The cladding 21 of the branch portion 20 is made of one of a tetrafluoroethylene / hexafluoropropylene copolymer and a tetrafluoroethylene / perfluoroalkylvinyl ether copolymer.

The cores of the optical fibers 22, 23, and 24 are made of a thermosetting silicone resin or an ultraviolet-curing silicone resin.

Such a branched plastic optical fiber 2
Reference numeral 9 denotes a core 28 of the branch section 20 and optical fibers 22 and 2.
There is no interface between cores 3 and 24 (regions indicated by broken lines). Moreover, the core 28 of the branch section 20 and the optical fiber 2
There is no need to position the 2, 23, 24 with the core 28.

[0022]

EXAMPLE A branched plastic optical fiber was manufactured using the cladding shown in FIG.

The number of branches of this branched plastic optical fiber is 2, and the cladding material of the branch portion is tetrafluoroethylene /
Hexafluoropropylene copolymer (refractive index 1.3
4) The core material of the optical fiber is a thermosetting silicone rubber resin (refractive index: 1.50).

The cladding 21 of the branching section 20 is formed by injection molding, and the cladding 2 of the optical fibers 22, 23, 24 is formed.
5, 26 and 27 are connected to the cladding 21 of the branch portion 20,
The core material 28a is injected into the claddings 25, 26, 27 of the optical fibers 22, 23, 24 and the cladding 21 of the branch portion 20, and is irradiated with ultraviolet rays to cure the core material 28a. The length of each optical fiber 22, 23, 24 of the formed branched plastic optical fiber 29 is 1 m, and the length of the branch portion 20 is 0.05 m.

When light is incident on the incident end (right end in the figure) of the branched plastic optical fiber, about 63% of the incident light
% Was emitted from the emission end (the left end in the figure). The loss of this branched plastic optical fiber was about 2 dB in total.

Comparative Example 1 FIG. 6 is a plan sectional view showing a comparative example of a branched plastic optical fiber.

As in the conventional method, the branch 30 and the optical fibers 31, 32, and 33 are separately formed, and then the branch 3 is formed.
0 core 34 and each core 3 of optical fibers 31, 32, 33
After alignment with 5, 36 and 37, connection is made.
The lengths of the optical fibers 31, 32, and 33, the branch structure, and the length of the branch portion 30 are the same as those in the embodiment.

The number of branches of the branched plastic optical fiber 38 is two, and the material of the cladding 39 at the branch portion is a tetrafluoroethylene / hexafluoropropylene copolymer (refractive index 1.34). Optical fibers 31, 32, 3
The material of the cores 35, 36, and 37 is a thermosetting silicone rubber resin (refractive index: 1.50).
The materials 1 and 42 are tetrafluoroethylene / hexafluoropropylene copolymers (refractive index 1.34). The core diameter / cladding diameter of the optical fibers 31, 32, and 33 is 7 m.
m / 8.5 mm.

About 50% of the light incident from the incident end (the right end in the figure) of the branched plastic optical fiber 38 is emitted from the outgoing end (the left end in the figure), and the loss is about 3 dB as a whole. It was about 1 dB larger than that of the plastic optical fiber 29.

In the above-described embodiment, the number of branches is not limited to two, but may be three, four, five,... Further, the core material may be an ultraviolet curing type. The core material is not limited to a silicone resin, but may be a resin such as acryl, polycarbonate, or polystyrene.

FIG. 2A is a view showing a modified example of an optical fiber core used for a branched plastic optical fiber to which the method for manufacturing a branched plastic optical fiber according to the present invention is applied, and FIG. It is a right view of a).

The optical fibers connected to the optical fibers 22, 23, 24 (see FIG. 1) of the branch plastic optical fiber 29 have a core diameter not the same as the core diameters of the optical fibers 22, 23, 24, and the light travels. What is necessary is just to increase with respect to the direction.

In the figure, the arrow A indicates the traveling direction of light. 50 is an optical fiber connected to the core 28 of the branching section 20.

FIG. 3A is a view showing a modified example of a core used for a branched plastic optical fiber to which the method for manufacturing a branched plastic optical fiber of the present invention is applied.
FIG. 3B is a right side view of FIG.

The optical fiber 51 connected to the branch portion 20 of the branch plastic optical fiber 29 only needs to have a larger sum of the core cross-sectional areas in the light traveling direction.

In the drawing, arrows B and C indicate the traveling directions of light. 28 is a core of the branching unit 20.

The branched plastic optical fiber of the present invention comprises:
The loss is smaller than that of the conventional example, and it can be applied to the lighting field such as a light guide and the information field such as a short-distance LAN.

[0038]

In summary, according to the present invention, the following excellent effects are exhibited.

It is possible to provide a method of manufacturing a branched plastic optical fiber having no interface and no interface.

[Brief description of the drawings]

FIG. 1 is a plan sectional view showing an embodiment of a branched plastic optical fiber to which a method for manufacturing a branched plastic optical fiber according to the present invention is applied.

FIG. 2A is a diagram showing a modified example of an optical fiber core used for a branched plastic optical fiber to which the method for manufacturing a branched plastic optical fiber of the present invention is applied;
(B) is a right side view of (a).

3A is a diagram showing a modified example of a core used for a branched plastic optical fiber to which the method for manufacturing a branched plastic optical fiber of the present invention is applied, and FIG.
FIG.

4A is a left side view of a branch portion used in a conventional branch plastic optical fiber, FIG. 4B is a plan sectional view, and FIG. 4C is a right side view.

FIG. 5A is a left side view of a branch portion used in another conventional branch plastic optical fiber, FIG. 5B is a plan sectional view, and FIG. 5C is a right side view.

FIG. 6 is a plan sectional view showing a comparative example of a branched plastic optical fiber.

[Explanation of symbols]

 Reference Signs List 20 branch part 21 clad 22, 23, 24 optical fiber 25, 26, 27 clad

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Bunken Middle East 5-1-1 Hidakacho, Hitachi City, Ibaraki Prefecture Inside the Hidaka Plant, Hitachi Cable Co., Ltd. (72) Inventor Yoshikazu Hayakawa Hidakacho, Hitachi City, Ibaraki Prefecture 5-1-1 F-term in the Hidaka Plant of Hitachi Cable, Ltd. F-term (reference) 2H050 AA14 AB42X AB43X AB45X AB46X AB48Y AC03 AC81

Claims (4)

[Claims] 1. A branch plastic optical fiber is manufactured by connecting a core of an optical fiber and a core of a branch portion in which a transparent resin branch core is covered with a transparent resin clad having a lower refractive index than the branch core. In the method for manufacturing a branched plastic optical fiber, the clad of the branch portion and the clad of the optical fiber are formed, and after connecting and integrating the two clads, a liquid core is injected into the clad and cured. Of manufacturing a branched plastic optical fiber. 2. The cladding of the optical fiber is made of polytetrafluoroethylene, tetrafluoroethylene / hexafluoropropylene copolymer, ethylene / tetrafluoroethylene copolymer, tetrafluoroethylene / vinylidene fluoride copolymer, tetrafluoroethylene Either an ethylene / hexafluoropropylene / vinylidenefluoride copolymer, wherein the cladding of the branch is one of a tetrafluoroethylene / hexafluoropropylene copolymer and a tetrafluoroethylene / perfluoroalkylvinyl ether copolymer The method for manufacturing a branched plastic optical fiber according to claim 1, wherein 3. The method according to claim 1, wherein the core of the optical fiber is a thermosetting silicone resin or an ultraviolet-curing silicone resin. 4. The method for manufacturing a branched plastic optical fiber according to claim 1, wherein the cladding of the branch portion is formed by injection molding.