JPH1010368A - Optical connector, manufacturing method thereof and molding tool - Google Patents

Abstract

(57) [Problem] An optical connector for connecting a plurality of optical fibers collectively using a ferrule manufactured by molding a resin,
The position of the outer fiber hole is more likely to deviate from a predetermined position due to thermal contraction and the like than the position of the inner fiber hole, and the connection loss tends to increase. A ferrule has a plurality of optical fibers.
By disposing a plurality of fiber holes 3 formed in parallel for inserting and fixing -1 and at least one dummy fiber hole 2 on both sides of the fiber holes 3, displacement of the fiber holes 3 is prevented. doing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical connector capable of connecting a plurality of optical fibers at a time with high precision, a method of manufacturing the same, and a tool therefor.

[0002]

2. Description of the Related Art As a low-cost method of manufacturing an optical connector for connecting a ribbon-type optical fiber composed of a plurality of optical fibers, a method using a ferrule molded from plastic has been developed (for example, Japanese Patent Application Laid-Open No. H11-163, 1988). JP-A-61-52612). FIG. 5 is a perspective view showing an example of the ribbon-type optical fiber 5 having a width (D1) of 1.5 m.
This shows a configuration in which four optical fibers 5-1 having a diameter of 125 μm are arranged in a line at a pitch of 0.3 mm in a ribbon-shaped coating 5-2 having a m and a thickness (t) of 0.25 mm. As shown in FIG. 6, such a connector for the ribbon-type optical fiber 5 is formed by a flat ferrule 1 for positioning and fixing the end of the ribbon-type optical fiber 5 and two guide pins 6. . As shown in FIG. 2B, the flat ferrule 1 has a guide pin hole 4 having a diameter of 0.7 mm.
The optical fibers 5-1 are arranged in a line at a pitch of 0.25 mm between the guide pin holes so as to match the ribbon-type optical fiber 5. In connection, the ferrule 1 is moved in the direction of the arrow 9 in FIG. 2A, and two guide pins 6 are inserted into the guide pin holes 4 of the ferrule 1 to perform mutual positioning and connection of the ferrules. Press and fix with a rear clip (not shown). Such a ferrule 1 is formed by press-fitting a resin into a molding die.

[0003]

A plurality of optical fibers 5-1 are formed using a ferrule 1 manufactured by molding a resin.
As shown in FIG. 2A, the position of the outer fiber hole 3-1 tends to be larger than the position of the inner fiber hole due to thermal shrinkage or the like from the predetermined position. There is. For this reason, the connection loss of the optical fiber at the end is increased, which is an obstacle in achieving a low connection loss of the optical connector. For example, as shown in FIG. 2, the displacement of the inner fiber hole is about 0.4 μm, while the displacement of the outer fiber hole is as large as about 1 μm. This means that the inner connection loss is about 0.2 dB,
The outer connection loss is as large as about 0.4 dB. Accordingly, an object of the present invention is to provide an optical connector capable of solving such a problem and suppressing an outer connection loss to be substantially equal to an inner connection loss, and a method of manufacturing the same.

[0004]

SUMMARY OF THE INVENTION An optical connector according to the present invention is an optical connector in which ferrules holding the tips of a plurality of optical fibers arranged in parallel are brought together and connected collectively to each other. A plurality of fiber holes are provided in parallel for inserting and fixing an optical fiber, and at least one dummy fiber hole is provided on both sides of the fiber hole.

Further, a method of manufacturing an optical connector according to the present invention is a method of manufacturing an optical connector, comprising the steps of: inserting a plurality of optical fibers into a plurality of fiber holes in parallel for inserting and fixing the plurality of optical fibers; A method of manufacturing an optical connector having a ferrule with a dummy fiber hole, wherein the ferrule is formed by processing a hard resin, and the dummy fiber hole is formed in the same step as a plurality of fiber holes. Features.

Further, the molding tool according to the present invention comprises a plurality of fiber holes drilled in parallel for inserting and fixing a plurality of optical fibers, and at least one dummy fiber on each side of the fiber holes. A molding tool for forming a ferrule with a hole, wherein the molding die has an inlet for press-fitting a resin, an outlet for overflowing, and a space for forming a ferrule, and a center of the die. A core corresponding to a plurality of optical fibers to be connected and a pin having substantially the same outer diameter and the same interval provided on both sides thereof at the tip of the core. Features.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the description of the drawings, the same elements will be denoted by the same reference symbols, without redundant description. FIG.
FIG. 2A is a perspective view showing an optical connector according to one configuration of the present embodiment, and shows a plurality of optical fibers 5 arranged in parallel.
As shown in FIG. 6, in an optical connector in which the ferrules 1 holding the distal end portions are butted together as shown in FIG. 6, a plurality of ferrules 1 are opened in parallel to insert and fix a plurality of optical fibers 5-1. And at least one dummy fiber hole 2 on each side of the fiber hole 3 (FIG. 2). FIG. 2B shows a case where a guide pin hole 4 is provided outside the dummy fiber hole 2.

The optical fiber used in this embodiment is a ribbon type optical fiber 5 in which four optical fibers 5-1 are arranged in parallel and covered with a coating 5-2 as shown in FIG. The coating 5-2 at the tip was removed with a remover, and the tip and the coating near the tip were fixed to the ferrule 1.

The ferrule 1 is provided with a fiber hole 3 for inserting four optical fibers 5-1 and at least one dummy fiber hole 2 on both sides of the hole, so as to have abrasion resistance and deformation resistance. It is formed of a hard resin rich in properties. FIG.
Is a cross-sectional view of a forming tool for forming a ferrule,
The molding die is composed of two upper and lower dies 7 and a core 8 shown in FIG. A core 8 for inserting and fixing the ribbon-shaped optical fiber 5 and the optical fiber 5-1 is arranged at the center,
The hard resin is pressed into the space provided in the center of the mold 7 from the resin inlet 7-1 and filled while overflowing from the outlet 7-2, and the ferrule 1 is formed by the resin filled in the space. Is done. The core 8 is provided with pins 8-2 corresponding to the four optical fibers 5-1 at the distal end and pins 8-2 having substantially the same outer diameter and the same interval on both sides thereof.
The root of the pin is formed of a tape-shaped plate 8-1 slightly larger than the ribbon-shaped optical fiber 5.

FIG. 2B is a cross-sectional view of the ferrule 1 formed as described above, and the fiber hole 3 is formed at a substantially predetermined position. However, the pins 8-2 having the same outer diameter and the same interval are used.
There is a tendency that the dummy fiber hole 2 formed by the above-mentioned method is opened at a position where it is displaced. As a result of examining this point, it was found that the inner hole is formed under substantially the same conditions, but the hole at the end is generated because the flow of the resin or the state of hardening of the resin is different from that at the inner side. Therefore, holes are formed on both sides of the fiber hole at the same time, but this hole is not used as a fiber hole. Accordingly, the inner diameter of the dummy fiber hole 2 is 0.124 to 0.127 mm, and the distance between the dummy fiber hole 2 and the adjacent fiber hole 3 is ± 0.05 m with respect to the distance between the fiber holes 3.
It is necessary to be equal in the range of m. If it is further away, it will not serve as a dummy fiber hole. Since the dummy fiber hole is not used after it has been formed, it is preferable to fill only the end portion in order to prevent the optical fiber from being inserted and assembled by mistake if it is open.

That is, in the method for manufacturing an optical connector according to the present invention, a hard resin is press-fitted from a resin inlet 7-1 of a mold.
The ferrule 1 is formed while the hard resin overflows from the resin discharge port 7-2. Multiple optical fibers 5
For manufacturing an optical connector having a plurality of fiber holes 3 arranged in a row for inserting and fixing the fiber holes 1 and a ferrule having at least one dummy fiber hole 2 on each side of the fiber holes 3. The ferrule 1 is formed of a hard resin, and a dummy fiber hole 2 is formed.
Are formed in the same step as the plurality of fiber holes 3.

[0012]

The present invention is embodied in the form described above and has the following effects.

Since the resin is formed by molding, it is suitable for mass production.

Further, since a plurality of fiber holes are inserted in a row for inserting and fixing a plurality of optical fibers, and at least one dummy fiber hole is provided on both sides of the fiber holes, the inner fiber holes are formed. The resin flows and hardens under substantially the same conditions, so that it can be opened at a predetermined position. Therefore, in the optical connector formed by abutting such ferrules, the connection loss does not increase because the optical fiber has a small axial deviation, and the variation in the connection loss between the optical fibers can be suppressed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of an optical connector according to the present invention.

FIG. 2 is a side view of a ferrule for explaining the operation and effect of the optical connector according to the present invention.

FIG. 3 is a cross-sectional view of a mold for molding a ferrule and a core.

FIG. 4 is a perspective view showing a configuration of a core.

FIG. 5 is a perspective view illustrating a configuration of a ribbon-type optical fiber.

FIG. 6A is a plan view for explaining the configuration of a conventional optical connector, and FIG. 6B is a side view of a ferrule.

[Explanation of symbols]

 1: ferrule 2: dummy fiber hole 3: fiber hole 3-1: outer fiber hole 4: guide pin hole 5: ribbon type optical fiber 5-1: optical fiber 5-2: coating 6: guide pin 7: gold Mold 7-1: Resin inlet 7-2: Resin outlet 8: Core 8-1: Tape-shaped plate 8-2: Pin 9: Arrow

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toru Yamanishi 1 Tayacho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Sumitomo Electric Industries, Ltd. Yokohama Works (72) Inventor Shinji Nagasawa 3--19 Nishishinjuku, Shinjuku-ku, Tokyo No. 2 Nippon Telegraph and Telephone Corporation

Claims (6)

[Claims] 1. An optical connector for connecting a plurality of optical fibers arranged in parallel with each other by abutting ferrules holding the end portions of a plurality of optical fibers, wherein the ferrules are opened in parallel to insert and fix the plurality of optical fibers. An optical connector comprising: a plurality of provided fiber holes; and at least one dummy fiber hole on each side of the fiber holes. 2. The optical connector according to claim 1, wherein the ferrule is formed of a hard resin. 3. The dummy fiber hole has an inner diameter of 0.124.
The optical connector according to claim 1, wherein the distance between the dummy fiber hole and the adjacent fiber hole is equal to the distance between the fiber holes within a range of ± 0.05 mm. 4. The optical connector according to claim 1, wherein holes for guide pins are provided outside the dummy fiber holes. 5. A ferrule having a plurality of fiber holes drilled in parallel for inserting and fixing a plurality of optical fibers, and at least one dummy fiber hole on each side of the fiber holes. A method for manufacturing an optical connector, wherein the ferrule is formed of a hard resin, and the dummy fiber hole is formed in the same step as a plurality of fiber holes. 6. A ferrule having a plurality of fiber holes drilled in parallel for inserting and fixing a plurality of optical fibers and at least one dummy fiber hole on each side of the fiber holes. A molding tool having an inlet for press-fitting the resin, a discharge port for overflowing, and a space for forming a ferrule, and a core held in a space of the mold. A molding tool comprising: a pin corresponding to a plurality of optical fibers to be connected; and a pin having substantially the same outer diameter and the same interval provided on both sides thereof at the tip of the core.