JP2000009948A - Optical fiber bundle and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical fiber bundle which is unified in the angle of polarization axes with high accuracy and is high in tensile strength by using an adhesive which is slow in a curing rate in adhesion of optical fibers to each other and using an adhesive having a high adhesion property into the spacings exclusive thereof. SOLUTION: The coatings 12 at the ends of polarization maintaining type coated optical fibers 10 are removed about several mm. A plurality of bare fibers 14 are bundled round and the portions of about 2/3 from the front ends are adhered to each other by the adhesive 30A which is slow in the curing rate. The polarization axes of the respective optical fibers are aligned to a specified direction by end face observation. The adhesive 30B having the high adhesion property is previously packed into a capillary 20 or is applied to the inside surface thereof and the optical fibers adhered to each other by the adhesive 30A which is slow in the curing rate are inserted therein. The adhesive 30b is then cured. The material of the capillary 20 is borosilicate glass or quartz, etc., and is formed of material transparent to UV rays at the time of using a UV curing resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarization-maintaining optical fiber bundle and a method of manufacturing the same, and an apparatus using the same is used as a component of an optical signal processing system using polarization.

[0002]

2. Description of the Related Art As shown in FIG.
Within 0, collect a plurality of polarization-maintaining optical fibers,
An optical fiber bundle has been proposed in which the polarization directions of the respective polarization-maintaining optical fibers are arranged at least at the end face, and an adhesive 30 is filled in the capillary 20.

FIG. 3 is an enlarged view schematically showing an end face of the bundle, wherein 15 is a core, 16 is a clad, and 18 is a stress applying portion.

[0004]

The properties of the adhesive include:
There are items such as curing speed and adhesion. For use in bundling polarization-maintaining optical fibers, a fiber having a low curing rate and high adhesion is desirable. The reason is as follows.

[0005] If the curing speed is high, the adhesive will be cured with insufficient time for adjusting the angle of the polarization axis of the optical fiber, and the angle of the polarization axis cannot be adjusted with high accuracy. In addition, when the adhesion is low, a problem such as a decrease in tensile strength occurs.

[0006] An adhesive having a low curing rate and high adhesion is generally difficult to obtain. Conventionally, an adhesive having a low curing speed has been used in order to precisely align the angles of the polarization axes.
However, this type of adhesive also has low adhesion. for that reason,
The tensile strength of the product was low.

[0007]

According to the present invention, as shown in FIG. 1, an adhesive 30A having a low curing speed is used for bonding the bare optical fibers 14, and the curing speed is low. It is characterized in that a highly adhesive adhesive 30B is used in a gap between a portion where the adhesive 30A is used and the capillary 20.

[0008] One mode of a fast and slow curing speed of the adhesive is, for example, a condition at normal temperature (not heated) and without irradiation with light, UV, or the like for promoting curing.

When the adhesive 30A having a slow curing speed is used only for a part of the length of the bare fiber 14 inserted into the capillary 20 as described in claim 2, the other properties of the bare fiber 14 Since the adhesive 30B having high adhesion is directly in contact with the portion, the tensile strength is further increased.

The invention according to claim 3 relates to a manufacturing method,
Outside the capillary 20, the optical fibers are adhered to each other with an adhesive 30A having a low curing speed, the polarization directions of the respective polarization-maintaining optical fibers are aligned, and then the polarization directions are aligned. An optical fiber is present in the capillary 20, and an adhesive 30B having high adhesion is provided in a gap between the capillary 20 and the adhesive 30A having a low curing speed.
Is set to exist.

In the above description, "the optical fiber whose polarization direction is aligned exists in the capillary 20, and the capillary 20 and the adhesive 30A having a low curing speed are used.
The adhesive 30B having a high adhesiveness is present in the gap between the adhesive 30B and the adhesive 30B having a high adhesiveness in the capillary 20. Insert a group of optical fibers that are fixed in direction and are hardened with an adhesive 30A with a slow curing speed, or insert an optical fiber into the capillary 20 first, and then fill the adhesive 30B with high adhesion with a syringe or the like. Yes, etc.

If the bare fibers 14 are adhered to each other with the adhesive 30A having a low curing speed, the polarization directions of the respective polarization-maintaining optical fibers can be aligned with high accuracy over time.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Object itself] At the ends of a plurality of polarization-maintaining optical fiber cores 10, a coating 12 is removed by several mm (FIG. 1), and a bare fiber 14 that is led out is polarized. It is inserted into the capillary 20 with the wave axes aligned. The material of the capillary 20 is borosilicate glass, quartz, or the like, and is a material that transmits ultraviolet light when using an ultraviolet curable resin.

The range of about 2/3 from the end of the bare fiber 14 in the capillary 20 is the adhesive 30 having a low curing speed.
By A, they are bonded to each other. Regarding the adhesiveness of the adhesive used in this portion, FC0708 (Dainippon Ink) or the like can be used as an adhesive having a low curing speed (usually low adhesiveness) regardless of its value.

A portion of the capillary 20 other than the portion of the bare fiber 14 hardened with the adhesive 30A having a low curing speed is filled with an adhesive 30B having high adhesion. Regarding the curing speed of the adhesive in this portion, R1159VN (JSR) or the like can be used as the adhesive 30B having a high adhesion (usually a high curing speed), regardless of particular.

[Manufacturing Method] The coating 12 on the end of the polarization maintaining optical fiber 10 is removed by about 5.5 mm. A plurality of bare fibers 14 are bundled in a round shape, and a portion of about 3 mm from the tip is bonded to each other with an adhesive 30A having a low curing speed (FIG. 1B). Then, each optical fiber polarization axis is
Align in a certain direction by observing the end face

The capillary 20 is filled with an adhesive 30B having high adhesion or applied to the inner surface thereof (FIG. 1).
(C)) The adhesive 30 having a low curing rate as described above.
The optical fibers bonded to each other in A are inserted, and the adhesive is cured.

Thereafter, the tip of the capillary 20 is polished.

[0019]

EXAMPLE As an adhesive 30A having a slow curing speed, FC0 was used.
708 (Dainippon Ink) was used. This has low adhesion. As the adhesive 30B having high adhesion, R11
59VN (JSR) was used. It has a fast curing speed. Samples according to the conventional method and the method according to the present invention were manufactured, and the tensile strength was measured. In the method of the present invention, a portion of 3 mm from the end of the bare fiber 14 in the capillary 20 having a length of 5 mm and having a low curing speed is used as the adhesive 3 having the structure shown in FIG.
The other parts were filled with an adhesive 30B having high adhesion. In the conventional method, only the adhesive 30A having a slow curing speed is used in the structure of FIG.

The polarization-maintaining optical fiber is a so-called panda-type, glass-based optical fiber.

As the adhesive, a photo-curing type is preferably used, but a room temperature-curing type, a one-component type, or a two-component type may be used. As the material, an epoxy-based or acrylate-based material can be suitably used.

The results are shown in the table below. Prototype Tensile strength Angle of polarization axis Conventional method 0.2 kg <± 2 degrees Inventive method 0.9 kg <± 2 degrees

It can be seen that the tensile strength of the sample according to the present invention is high.

[0024]

According to the present invention, it is possible to manufacture an optical fiber bundle in which the angles of the polarization axes are aligned with high precision and the tensile strength is large.

[Brief description of the drawings]

FIG. 1 is an explanatory view of the present invention, wherein (a) shows a state of a finished product viewed from a side, and (b) and (c) show a state of being manufactured.

FIG. 2 is an explanatory diagram of a conventional technique.

FIG. 3 is an explanatory view in which an end face of a conventional optical fiber bundle is enlarged.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Polarization-maintaining optical fiber core wire 12 Coating 14 Bare fiber 15 Core 16 Cladding 18 Stress applying part 20 Capillary 30A Adhesive with slow curing speed 30B Adhesive with high adhesion

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideyuki Hosoya 1440, Misaki, Sakura City, Chiba Prefecture Fujikura Co., Ltd. Sakura Plant F-term (reference) 2H046 AA03 AA42 AC28 AZ01

Claims (4)

[Claims] 1. A plurality of polarization-maintaining optical fibers are assembled in a capillary, and are arranged so that the polarization directions of the respective polarization-maintaining optical fibers are aligned at least at an end face.
In the optical fiber bundle formed by filling the capillary with an adhesive, an adhesive 30A having a slow curing speed is used for bonding the optical fibers, and a portion where the adhesive 30A having the slow curing speed is used. An optical fiber bundle, wherein an adhesive 30B having high adhesion is used in a gap between the capillary and the capillary. 2. The light according to claim 1, wherein the adhesive 30A having a low curing speed is used only for a part of the optical fiber inserted into the capillary 20 in the length direction. Fiber bundle. 3. A plurality of polarization-maintaining optical fibers are arranged in a capillary, and are arranged so that the polarization directions of the respective polarization-maintaining optical fibers are aligned at least at an end face, and an adhesive is provided in the capillary. When the optical fiber bundle is filled, the optical fibers are bonded to each other with the adhesive 30A having a low curing speed outside the capillary 20, and the polarization of each polarization-maintaining optical fiber is adjusted. The gap between the capillary 20 and the portion fixed by the adhesive 30A having a low curing speed, in which the optical fiber whose polarization direction is aligned is present in the capillary 20 and the polarization direction is aligned. A method of manufacturing an optical fiber bundle, wherein an adhesive 30B having high adhesion is present. 4. The optical fiber according to claim 3, wherein the optical fibers inserted into the capillary 20 are bonded to each other only in a part of the length direction by an adhesive 30A having a low curing speed. The method of manufacturing the bundle.