JP2003014970A - Mechanical splice - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reliable mechanical splice. SOLUTION: Opposed optical fibers 2a and 2b are butted and connected in the state where coated optical fiber 2aa and 2ba at the tip part are bent. Because each coated optical fiber 2aa and 2ba comes into contact with either a V-grooved substrate 4 or a presser foot substrate 5, bending does not advance from an initial state, and optical loss is not increased. Thereby, the breaking of wire of the optical fibers 2a and 2b is prevented, and the initial state is maintained with high reliability.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a mechanical splice for connecting optical fibers to each other.

[0002]

2. Description of the Related Art In the field of communication, optical fibers capable of high-speed and large-capacity transmission have become the mainstream of transmission lines, and most of medium- and long-distance trunk lines have already replaced conventional metal cables with optical cables. Furthermore, commercialization of an optical subscriber transmission system, in which the lines up to each household are also made into optical fibers, has begun.

Conventionally, fusion splicing has been performed for connecting optical fibers. The fusion splicing is highly reliable because the splicing surfaces of the optical fibers are melted and connected, but on the other hand, it takes time to reinforce after splicing, the equipment is expensive, and current is required. Was there.

Therefore, a mechanical splice, such as disclosed in Japanese Patent Laid-Open No. 9-31886, which proposes an optical fiber that is axially aligned with a V-groove or the like and fixed for easy connection, has been proposed and developed. It is being advanced. This mechanical splice is expected to reduce the cost of connection due to the structure and the simplicity of the connection method.

FIG. 3 is an external perspective view of a conventional mechanical splice. 4A to 4C are explanatory views of the optical fiber connection method of the mechanical splice shown in FIG. 3, and FIG. 4D is a cross-sectional view taken along the line AA of FIG. 4A.
4E is a sectional view taken along line BB of FIG. 4B, and FIG. 4F is a sectional view taken along line CC of FIG. 4C.

As shown in FIG. 3, the conventional mechanical splice 31 includes cores 33a of optical fibers 32a and 32b,
A V-groove substrate 35 in which a V-groove 34 for aligning 33b is formed, and three-divided pressing substrates 36a, 36b, 36 for pressing and fixing from the upper portion of the V-groove substrate 35.
c, and a clamp spring 37 for gripping and fixing the V-groove substrate 35 and the pressing substrate 36 from above and below.

When the optical fibers 32a and 32b are connected to each other, a wedge 39 is inserted into the wedge insertion groove 38 between the V-groove substrate 35 and the pressing substrate 36 to spread the wedge (FIG. 4).
(A)), mechanical splice 3 when a gap is created
The optical fibers 32a and 32b are respectively inserted from both ends of the optical fiber 1, and the core wires 33a and 33b are butted (see FIG. 4).
(B)) By pulling out the wedge 39 after the core wires 33a, 33b are butted against each other, the restoring force of the clamp spring 37 causes the optical fibers 32a, 32b to reach the V groove 34.
Are positioned and gripped (FIG. 4 (c)).

The mechanical splice shown in FIG. 3 is φ
It is intended for connection between optical fibers of 0.25 mm single-core wire.

[0009]

By the way, a single-core wire having a diameter of 0.9 mm is widely used as a single-core wire of an optical fiber, and is intended for connection between optical fibers having a single-core wire having a diameter of 0.9 mm. Mechanical splicing has become a necessity. Among the optical fibers having a diameter of 0.9 mm, the optical fiber coating portion may be made of a material having a large shrinkage ratio such as nylon.

FIGS. 5 and 6 are partially enlarged views of the mechanical splice shown in FIG.

As shown in FIG. 5, φ0.9 mm having the same structure as the mechanical splice 31 for φ0.25 mm.
In the mechanical splice 41 for use, when the optical fiber coating portions 52a and 52b contract due to a change in environment, the optical fiber coating portions 52a and 52b are fixed between the V groove substrate 42 and the pressing substrate 43 by the clamp spring 44. Since the bare fibers (cores) 51a and 51b are projected and the ends of the cores 51a and 51b are also fixed, the bend 53 as shown in FIG. Occurs, and the light loss increases. Further, when the protrusion amount is large, there is a problem that the core wires of the optical fibers 51a and 51b cannot be endured and are broken due to stress due to bending.

Therefore, an object of the present invention is to solve the above problems and provide a mechanical splice with high reliability.

[0013]

In order to achieve the above object, the mechanical splice of the present invention has a core wire V arranged in a state where the core wires of the optical fibers whose end portions have been removed are butted against each other. A V-groove substrate integrally formed with a V-groove for a covering portion, in which the groove and each covering portion of the optical fiber are arranged;
A core wire pressing substrate in which a core wire flat surface portion is formed for pressing the core wires of the optical fibers arranged in the grooved substrate in abutment state, and a covering portion flat surface portion for pressing the covering portion, respectively. A mechanical splice including a formed cover pressing board and a clamp spring for sandwiching the V groove board and each pressing board at the same time to hold an optical fiber. So that the optical axis of the optical fiber between them and the optical axis of the optical fiber between the V groove for the covering portion and the flat surface portion for the covering portion intersect with each other It is inclined with respect to the groove and the flat portion for the core wire.

In addition to the above structure, in the mechanical splice of the present invention, in the optical axis converting portion in which the core of the optical fiber is bent in the V groove, the outer peripheral surface of the core is either the V groove substrate or the pressing substrate. Is preferably in contact with.

According to the present invention, the opposing optical fibers are
The core wires at the tip are butt-connected in a bent state, but since each core wire is in contact with either the V-groove substrate or the pressing substrate, the core wires do not bend more than in the initial state. The light loss does not increase. Therefore, it is possible to prevent disconnection of the optical fiber and maintain the initial state with high reliability.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 (a) is an external perspective view of the mechanical splice of the present invention, and FIG. 1 (b) is D- of FIG. 1 (a).
FIG. 1C is a sectional view taken along line D, and FIG. 1C is a partial sectional view when an optical fiber is inserted into the mechanical splice shown in FIG. In addition, in order to simplify the description, FIG.
Then, only the right half is shown.

The present mechanical splice 1 has core wires 2aa and 2b of the optical fibers 2a and 2b from which the coatings on the ends are removed.
A connector for connecting a by butting each other,
The V-grooves 3a for the cores arranged in a state where the cores 2aa, 2ba of the optical fibers 2a, 2b are arranged in abutment with each other, and the V-grooves 3c, 3e for the cover parts in which the coatings 2ac, 2bc of the optical fibers 2a, 2b are arranged. A V-groove substrate 4 integrally formed with
The core wire 2 of the optical fibers 2a and 2b arranged on the V-groove substrate 4
A core wire pressing board 5a in which a core wire flat portion 5aa for pressing the aa and the ba together is formed.
A cover portion holding substrate 5b, 5c having flat portion portions 5ba, 5ca for holding the covering portions 2ac, 2ba of the optical fibers 2a, 2b, a V-groove substrate 4 and each holding substrate 5a, 5b. And a clamp spring 6 for gripping the optical fibers 2a and 2b by sandwiching 5c at the same time,
The optical axes of the optical fibers 2aa and 2ba between the core V groove 3a and the core flat portion 5aa, and the optical fibers 2a and 2 between the covering V grooves 3c and 3e and the covering flat portions 5ba and 5ca.
The V-grooves 3c and 3e for the covering portion are arranged so that the optical axis of b may intersect.
The flat portions 5ba and 5ca for the covering portion are inclined by an angle θ with respect to the V-groove 3a for the core wire and the flat portion 5aa for the core wire.

V-groove 3 (3a, 3b, 3c, 3d, 3e)
Is a core wire 2a of the optical fibers 2a and 2b to be butted.
It is formed along the longitudinal direction of the V-groove substrate 4 in the same number as that of a and 2ba (the number is one but not limited in the figure). Of the V-shaped groove 3, the V-shaped groove 3a is a portion for positioning and aligning the optical fibers 2a and 2b, and the V-shaped grooves 3b and 3d are for guiding to the V-shaped groove 3a for aligning the optical fibers 2a and 2b. The V-grooves 3c and 3e are guide grooves, and the optical fibers 2 are
It is a V groove for aligning and positioning the covering portions 2ac and 2bc of a and 2b. The optical axis converting portion is formed between the V grooves 3b and 3d and the flat surface portion 5aa.

The portions of the V-groove substrate 4 for positioning and aligning the optical fibers 2a, 2b are located in the central portion in the longitudinal direction and are formed to have substantially the same depth and width, and both sides of the mechanical splice 1 are formed. Optical fiber 2a, 2b inserted from
Are aligned and matched.

Inside the clamp spring 6, there are formed convex portions (concave portions when viewed from the outside) 9 extending toward the V-groove substrate 4 and the pressing substrates 5a, 5b, 5c. The protrusions 9 are formed by extruding the clamp springs 6 in a circular shape at predetermined intervals in the longitudinal direction.

The cross sectional shape of the V groove is not limited to the V shape, but may be a U shape, a semicircle or a rectangle.

The V-groove substrate 4 and each pressing substrate 5a, 5b, 5
The wedge insertion groove 8 is provided at the open end of the overlapping portion with c.
By inserting a wedge (not shown) into the wedge insertion groove 8, the V-groove substrate 4 and the pressing substrates 5a, 5b, 5c are opposed to the restoring force of the clamp spring 6.
And open to form a gap. After inserting the end-treated optical fibers 2a and 2b into the gap from both ends and abutting the core wires 2aa and 2ba in the V groove 3,
The wedge is removed and the optical fibers 2a and 2b are connected to the V-groove substrate 4
The holding boards 5a, 5b, and 5c are gripped and fixed and connected. The optical fibers 2a and 2b are
The V-groove substrates 4 are abutted at the central portion in the longitudinal direction.

In the mechanical splice 1 of the present invention, the optical fibers 2a and 2b are connected in a bent state.

In this embodiment, the V grooves 3c and 3e formed on the V groove substrate 4 are formed at an angle θ with respect to the V groove 3a, and the insertion portions of the optical fibers 2a and 2b are bent. The case of being connected is explained.

The V groove 3a formed on the V groove substrate 4 of the mechanical splice 1 is formed substantially parallel to the bottom surface of the V groove substrate 4, whereas the V grooves 3c and 3e are formed on the V groove 3a. Is formed linearly in a direction forming an angle of θ ° with respect to.

On the other hand, the pressing substrate 5a has a flat surface portion 5aa horizontal to the V groove 3a, and the pressing substrates 5b and 5c are V-shaped.
It has plane portions 5ba and 5ca which are horizontal to the grooves 3c and 3e, respectively. When the optical fibers 2a and 2b are connected to each other, the optical fibers 2a and 2b have a V groove 3a and a V groove 3 respectively.
It is in a state of being bent between c and 3e, that is, a portion located in the guide grooves 3b and 3d.

Here, as shown in FIG. 1 (c), since the outer peripheral surfaces of the cores 2ba of the optical fibers 2a and 2b are in contact with the pressing substrate a5, it is difficult for the bending to proceed in the bent direction. Even if the core wire (naked optical fiber) tries to stick out, it cannot buckle, so that it is possible to prevent disconnection of the optical fibers 2a and 2b and maintain the initial connection state with high reliability.

Specifically, the mechanical splice 1 is
When 0 pieces were manufactured and a temperature cycle test (−40 ° C., 6 h / cycle × 10 cycles) was carried out, in the mechanical splice 31 which is a conventional prototype, the optical fibers 32a and 32b are broken. On the other hand, in the mechanical splice 1 of the present invention, there was no disconnection, and the good result that the increase in optical loss was 0.3 dB or less was obtained.

FIG. 2 (a) is a sectional view showing another embodiment of the mechanical splice of the present invention, and FIG. 2 (b) is a partially enlarged view of FIG. 2 (a). In order to simplify the description, only the right half is shown in FIG.

V-groove substrate 24 of mechanical splice 21
The V groove 23a formed in the center of the V groove and the V grooves 23c and 23e formed on both sides of the V groove 23a are the core wire 22a of the optical fiber 22c and the core wire of the optical fiber not shown in the figure. Optical fiber 22 when and are butt-connected
The depths of both V grooves 23c and 23e are set so that the optical axis of c is displaced. At this time, the optical fiber 22c is connected in a bent state at the optical axis converting portion between the guide groove 23b and the flat surface portion 25aa of the pressing substrate 25, as shown in FIG.
The same effect as the mechanical splice 1 shown in (c) can be obtained.

In the above, according to the present invention, the optical fiber is already bent while being connected, but since the optical fiber is in contact with either the V-groove substrate or the pressing substrate, the initial stage It is possible to provide a mechanical splice in which bending does not proceed further than in the state, optical loss does not increase, breakage of the optical fiber can be prevented, and the initial state can be maintained with high reliability.

[0033]

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

It is possible to realize the provision of a mechanical splice with high reliability.

[Brief description of drawings]

1A is an external perspective view of a mechanical splice of the present invention, FIG. 1B is a sectional view taken along the line D-D of FIG. 1A, and FIG. 1C is the mechanical splice shown in FIG. It is a fragmentary sectional view when inserting an optical fiber.

FIG. 2 (a) is a cross-sectional view showing another embodiment of the mechanical splice of the present invention, and FIG. 2 (b) is a partially enlarged view of (a).

FIG. 3 is an external perspective view of a conventional mechanical splice.

4A to 4C are explanatory views of an optical fiber connecting method of the mechanical splice shown in FIG. 3, FIG. 4D is a sectional view taken along line AA of FIG. 4A, and FIG. 7B is a sectional view taken along line BB, and FIG. 6F is a sectional view taken along line CC of FIG.

5 is a partially enlarged view of the mechanical splice shown in FIG.

6 is a partially enlarged view of the mechanical splice shown in FIG.

[Explanation of symbols]

1 mechanical splice 2a, 2b optical fiber 3 V groove 4 V groove substrate 5 pressing board 6 Clamp spring

Continued front page    (72) Inventor Kazuya Murakami             Hitachi, 1-1 Hidaka-cho, Hitachi City, Ibaraki Prefecture             Electric Cable Co., Ltd., Optro System Research Center (72) Inventor Masaaki Takatani             2-3-1, Otemachi, Chiyoda-ku, Tokyo             Inside Telegraph and Telephone Corporation (72) Inventor Shinji Nagasawa             2-3-1, Otemachi, Chiyoda-ku, Tokyo             Inside Telegraph and Telephone Corporation F-term (reference) 2H036 LA03 LA08 MA01 NA01

Claims (2)

[Claims] 1. A V-groove for a core wire which is arranged in a state where the core wires of an optical fiber whose end portions are not covered with each other are butted against each other, and a V-groove for a cover portion in which each cover portion of the optical fiber is arranged. A V-groove substrate integrally formed with the core substrate, and a core-fiber pressing substrate having a core-fiber flat portion for pressing the optical fibers arranged in the V-groove substrate in a state where the core fibers are abutted against each other. A cover pressing substrate for forming a cover flat portion for pressing the cover, and a clamp spring for holding the optical fiber by simultaneously sandwiching the V groove substrate and each pressing substrate. In the provided mechanical splice, the optical axis of the optical fiber between the V-groove for the core wire and the flat portion for the core wire and the optical axis of the optical fiber between the V-groove for the covering portion and the flat surface portion for the covering portion are The V-groove for the covering part and the upper part so that they intersect. A mechanical splice characterized in that the flat portion for the covering portion is inclined with respect to the V-groove for the core wire and the flat surface portion for the core wire. 2. The outer peripheral surface of the core wire of the optical axis conversion part in which the core wire of the optical fiber is bent in the V groove,
The mechanical splice according to claim 1, which is in contact with either the groove substrate or the pressing substrate.