JP3523553B2 - Mechanical splice - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanical splice for butt-connecting opposing optical fiber core wires.

[0002]

2. Description of the Related Art In the field of communications, optical fibers capable of high-speed and large-capacity transmission have become the mainstream of transmission lines, and most of the medium and long distance trunk lines have already replaced conventional metal cables with optical fiber cables. Furthermore, in a few years, efforts are being made at a rapid pace to realize an optical subscriber transmission system in which the lines up to homes are also made into optical fibers.

Conventionally, fusion splicing has been performed for connecting optical fibers. The fusion splicing is highly reliable because the butt 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 a power source is required. Was becoming.

Therefore, a mechanical splice as disclosed in Japanese Patent Application Laid-Open No. 9-318863 was devised and developed in which a mechanical splice for axially aligning an optical fiber with a V groove or the like and fixing the optical fiber for easy connection is devised. ing. This mechanical splice is expected to reduce the cost of connection because of the simplicity of its structure and connection method.

As shown in FIG. 5, in a conventional mechanical splice 51, a V-groove substrate 55 having a V-groove 54 for aligning a core wire 53 of an optical fiber 52, and a core wire 53 from the upper portion thereof. Presser board 56 for pressing and fixing
And a clamp spring 57 for holding and fixing the V-groove substrate 55 and the pressing substrate 56 from above and below.

When connecting the optical fiber 52, the wedge 59 is inserted into the wedge insertion groove 58 between the V-groove substrate 55 and the pressing substrate 56 to push it out, and the optical fiber 52 is inserted from both ends into the gap. After the core wires 53 are butted against each other, the wedge 59 is pulled out, and the optical fiber 52 is positioned and gripped in the V groove 54 by the restoring force of the clamp spring 57.

Incidentally, the mechanical splice 5 shown in FIG.
Although 1 is for a single core, there is also a mechanical splice 61 for 4 cores as shown in FIG. In this mechanical splice 61, four rows of V grooves 62 are formed, and each core wire 63 is inserted into each V groove 62.

[0008]

By the way, in recent years, a cable using an eight-core optical fiber is often used for a main trunk line or the like because of an increase in the amount of information. Therefore, 8
There is a need for a mechanical splice for your heart.

Therefore, the inventors of the present invention, as shown in FIG.
With the same structure as the mechanical splice 61 for 4 cores, V
A mechanical splice 65 having eight rows of grooves 64 was prototyped.

However, in the above-mentioned mechanical splice 65, since the resin is used for the V-groove substrate 67 and the pressing substrate 68 in order to reduce the cost, its rigidity is not high.

Therefore, the V-groove substrate 67 and the pressing substrate 6
Since both widthwise outer sides of 8 are warped, the clamp spring 6
Although the core wire 72a positioned within the width of the convex portion 71 of 9 can be reliably gripped, no force is applied to the core wire 72b outside the core wire 72a, and gripping becomes insufficient, and when the core wire 72b is subjected to a temperature cycle. There is a problem in that a gap is generated in the abutting portion of the optical fibers, and the increase in connection loss is large, and the increase in connection loss is large during handling such as storage after connection.

As a method for preventing this, it is conceivable to increase the width of the convex portion 71. In this case, the interval between the convex portions 71 and the total thickness of the V-groove substrate 67 and the pressing substrate 68 are completely the same. Otherwise, the protrusion 71 of the clamp spring 69
It is known that the V-groove substrate 67 and the pressing substrate 68 are in one-sided contact with each other, and the gripping force of the optical fiber varies. Therefore, the manufacturing accuracy of the mechanical splice 65 must be increased, which causes a problem of increasing cost.

Therefore, the present invention has been devised to solve the above problems, and an object thereof is to provide a mechanical splice which is inexpensive and can surely grip the whole even if it is a multi-fiber optical fiber. To provide.

[0014]

In order to solve the above-mentioned problems, the present invention provides a V-groove substrate having V-grooves for abutting and supporting optical fibers facing each other for positioning and alignment, and to the above-mentioned V-grooves. A mechanical splice including a pressing board having a flat surface for pressing the inserted optical fiber, and a clamp spring for holding the optical fiber by sandwiching the V-groove board and the pressing board. A convex portion extending toward the V-groove substrate and the pressing substrate is formed, and at least one of the V-groove substrate and the pressing substrate has a surface opposite to a surface in contact with the inserted optical fiber,
A recess having a width narrower than the width of the optical fiber is formed along the optical axis along a part or the whole of the recess, and a flat spacer substrate is provided between the substrate having the recess and the clamp spring. It is provided.

According to the above structure, the clamping force of the clamp spring is transmitted to the outer side in the width direction of the V-groove substrate or the pressing substrate through the spacer substrate, so that the V-groove substrate or the pressing substrate does not warp and the optical Even if the number of cores of the fiber is large, it is possible to uniformly and surely grip the outer side in the width direction. Further, since the manufacturing accuracy is the same as the conventional one, it is possible to prevent cost increase.

Further, the present invention has a V-groove substrate having V-grooves for abutting and supporting optical fibers facing each other for positioning and alignment, and a flat surface for pressing the optical fibers inserted in the V-grooves. In a mechanical splice including a pressing board and a clamp spring for holding the optical fiber by sandwiching the V-groove board and the pressing board, a protrusion extending toward the V-groove board and the pressing board inside the clamp spring. And a hole having a width narrower than the width of the optical fiber is formed inside at least one of the V-groove substrate and the pressing substrate along the optical axis direction.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment for carrying out the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a sectional view showing an embodiment of a mechanical splice according to the present invention, and FIG. 2 is a perspective view showing an embodiment of a mechanical splice according to the present invention.

First, the structure of the mechanical splice will be described.

As shown in FIG. 1, the mechanical splice 1 is a connector for facing the optical fiber 2 and inserting it from both sides for butt connection, and supports the optical fiber 2 for positioning. A rod-shaped V-groove substrate 4 having a V-groove 3 having a substantially V-shaped cross section, and a holding substrate 5 having a flat surface for overlapping the V-groove substrate 4 and holding the optical fiber 2 inserted in the V-groove 3. , And a clamp spring 6 having a U-shaped cross section for holding the optical fiber 2 by sandwiching the V-groove substrate 4 and the pressing substrate 5.

Inside the clamp spring 6, a convex portion 11 extending toward the V-groove substrate 4 and the pressing substrate side 5 is formed. The convex portions 11 are formed by extruding the clamp spring 6 into a circular shape at predetermined intervals in the longitudinal direction.

The pressing substrate 5 is divided into a portion for pressing the bare core wire 7 which is exposed by peeling the optical fiber 2 and an unpeeled portion, and is integrally supported by the clamp spring 6. Has been done.

The V-grooves 3 are formed along the longitudinal direction of the V-groove substrate 4 in the same number as the number of the core wires 7 of the optical fibers 2 to be abutted (here, eight). The longitudinal center portion of the V groove 3 is formed so that its depth and width are substantially the same as the core wire 7, and the optical fibers 2 inserted from both sides are aligned and abutted. On the other hand, both longitudinal end portions of the V groove 3 are formed deeper than the central portion, and the connecting portions thereof are formed in a tapered shape and are connected to each other.

The cross-sectional shape of the V groove 3 is not limited to the V shape, but may be a U shape, a semicircle or a rectangle.

A wedge insertion groove 8 is formed at the open end of the optical fiber gripping member 7 of the overlapping portion of the V-groove substrate 4 and the pressing substrate 5, and the wedge insertion groove 8 has a wedge (not shown). Clamp spring 6 by inserting
Open the V-groove substrate 4 and the pressing substrate 5 against the spring force of
It is designed to form a gap. The end-treated optical fiber 2 is inserted into this gap from both ends, the core wires 7 are butted against each other in the V-groove 3, and then the wedge is removed.
Is held and fixed and connected by the V-groove substrate 4 and the pressing substrate 5. The optical fiber 2 is abutted at a substantially central portion of the V-groove substrate 4 in the longitudinal direction.

By the way, according to the present invention, a width narrower than the width of the optical fiber 2 is provided on at least one of the V-groove substrate 4 and the pressing substrate 5 on the surface opposite to the surface in contact with the inserted optical fiber 2. The recessed portion 12 having the recessed portion 12 is formed over a part or all of the recessed portion along the optical axis direction, and the flat plate-shaped spacer substrate 1 is provided between the substrate on which the recessed portion 12 is formed and the clamp spring 6.
4 is provided.

In the present embodiment, the case where the depression 12 is formed in the pressing substrate 5 will be described.

The pressing substrate 5 in this case is formed to have a thickness half that of the conventional one. Then, the above-mentioned concave portion 12 is formed on the upper surface opposite to the plane for pressing the optical fiber 2.
Is formed at a substantially central portion in the width direction.

The recess 12 is formed over the entire length of the pressing substrate 5 located at the portion for pressing the core wire 7. The concave portion 12 may be partially formed in accordance with the position of the convex portion 11 of the clamp spring 6.

A spacer substrate 14 having the same thickness as that of the pressing substrate 5 is provided on the pressing substrate 5. The spacer substrate 14 is formed in a flat plate shape having the same width and length as the pressing substrate 5, and the lower surface of the spacer substrate 14 and the upper surface of the pressing substrate 5 are in surface contact with each other. The upper surface on the back side (left side in the drawing) of the clamp spring 6 is chamfered.

Next, the operation of the mechanical splice 1 having the above construction will be described.

When the optical fiber 2 is gripped by the mechanical splice 1, the clamping force of the clamp spring 6 is
It is transmitted to the pressing substrate 5 via the spacer substrate 14.

At this time, at the center of the pressing substrate 5 in the width direction,
By providing the concave portion 12, the clamping force is dispersed and transmitted from the spacer substrate 14 to the outer side in the width direction of the pressing substrate 5. As a result, both outer sides of the pressing board 5 are urged downward, so that the outer sides do not warp upward.

Therefore, the lower plane of the pressing substrate 5 can be kept flat, the core wire 7 of the optical fiber 2 can be pressed uniformly, and the optical fiber 2 can be reliably gripped. Therefore,
Even when subjected to a temperature cycle, no gap is created in the abutted portion of the optical fiber, and an increase in connection loss can be reduced.

Specifically, 20 mechanical splices 1 for 8 cores were manufactured, and a temperature cycle test of 10 cycles was carried out with -40 to 70 ° C / 6h as one cycle. While the loss increase of a certain mechanical splice 65 for 8 cores was 0.3 dB or more, the mechanical splice 1 of the present invention had a good result that the loss increase was 0.1 dB or less.

Further, the pressing substrate 5 has a thickness half that of the conventional one, and the spacer substrate 14 having the same thickness as that of the pressing substrate 5 is provided on the pressing substrate 5, so that the gripping surface of the core wire 7 has the thickness of the clamp spring 6. The clamping force of the clamp spring 6 is transmitted to the core wire 7 in a well-balanced manner in the center, and the gripping force can be effectively kept large.

Further, according to the present invention, the V-groove substrate 4, the pressing substrate 5, and the spacer substrate 14 can be manufactured with the same inexpensive resin as the conventional one, and the manufacturing accuracy is the same as the conventional one, so that the cost is increased. Can be prevented.

FIG. 3 is a sectional view showing another embodiment of the mechanical splice according to the present invention, and FIG. 4 is a perspective view showing another embodiment of the mechanical splice according to the present invention.

As shown in FIG. 3, a mechanical splice 21 according to another embodiment is formed by forming a hole 23 having a width narrower than that of the optical fiber 2 in the pressing substrate 22 along the optical axis direction. is there. The hole 23 is formed so as to penetrate substantially the central portion in the width direction and the thickness direction of the pressing substrate 22, and is located above the approximately central portion in the width direction of the V groove 3.

In other words, in the mechanical splice 21 of the present embodiment, the pressing substrate 5 and the spacer substrate 14 are integrally formed, and the hole 23 plays the same role as the recess 12 of FIG. .

Since the other parts are the same as those of the mechanical splice 1 of FIG. 1, the same reference numerals are given and the description thereof will be omitted.

In this mechanical splice 21, when the optical fiber 2 is gripped, the clamping force of the clamp spring 6 is directly transmitted to the pressing board 5.

At this time, since the pressing board 5 is provided with the holes 23, the clamping force is dispersed and transmitted to the outside of the holes 23 at the central portion in the thickness direction of the pressing board 5, and is transferred to the lower plane. Is transmitted. Therefore, both outer sides of the pressing board 5 are not biased downward and the outer sides do not warp upward.

Therefore, the mechanical splice 1 of FIG.
It is possible to obtain the same operational effect as.

In the above embodiment, the recess 12 or the hole 23 is formed on the side of the pressing substrates 5 and 22, but the invention is not limited to this, and the recess 12 or the hole 23 is formed on the side of the V-groove substrate 4. May be formed.
Further, the concave portion 1 is formed on both the V-groove substrate 4 and the pressing substrates 5 and 22.
2 or a hole 23 may be formed.

Further, in the above embodiment, the V groove 3
Is formed in eight rows, but is not limited to this. When connecting an optical fiber having a larger number of core wires, it is sufficient to provide V grooves for the number of the core wires.

[0047]

In summary, according to the present invention, since the V-groove substrate or the pressing substrate does not warp, even the multi-fiber optical fiber can surely be gripped as a whole and is an inexpensive material. Can manufacture V-groove substrate and pressing substrate,
In addition, since the manufacturing accuracy may be the same as the conventional one, the excellent effect that the cost increase can be prevented is exhibited.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a mechanical splice according to the present invention.

FIG. 2 is a perspective view showing an embodiment of a mechanical splice according to the present invention.

FIG. 3 is a cross-sectional view showing another embodiment of the mechanical splice according to the present invention.

FIG. 4 is a perspective view showing another embodiment of the mechanical splice according to the present invention.

FIG. 5 is a perspective view and a sectional view showing a conventional mechanical splice.

FIG. 6 is a perspective view and a sectional view showing a conventional mechanical splice.

FIG. 7 is a cross-sectional view showing a trial-produced conventional mechanical splice.

[Explanation of symbols]

1 mechanical splice 2 optical fiber 3 V groove 4 V groove substrate 5 pressing board 6 Clamp spring 11 convex 12 recess 14 Spacer substrate 21 mechanical splice 22 Pressing board 23 holes

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshihiro Nakatani 5-1-1 Hidaka-cho, Hitachi City, Ibaraki Pref., Hitachi Systems, Ltd. (72) Inventor Hidekazu Abe Hidaka, Hitachi City, Ibaraki Prefecture 5-1-1, Machi Nititsu Electric Cable Co., Ltd., Optro System Research Center (72) Inventor Masaaki Takatani 2-3-1, Otemachi, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Inventor Toshiaki Katagiri Tokyo 2-3-1, Otemachi, Chiyoda-ku, Nippon Telegraph and Telephone Corporation (56) Reference JP-A-9-96732 (JP, A) JP-A-9-318836 (JP, A) JP-A-2000-9962 ( JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G02B 6/24 G02B 6/36-6/40

Claims (2)

(57) [Claims] 1. A V-groove substrate having V-grooves for abutting and supporting optical fibers facing each other for positioning and alignment.
A mechanical splice including a pressing board having a flat surface for pressing the optical fiber inserted in the V groove, and a clamp spring for holding the optical fiber by sandwiching the V groove board and the pressing board. A convex portion extending toward the V-groove substrate and the pressing substrate is formed inside the spring, and at least one of the V-groove substrate and the pressing substrate has a surface opposite to a surface in contact with the inserted optical fiber,
A recess having a width narrower than the width of the optical fiber is formed along the optical axis direction over a part or all of the recess, and a flat spacer substrate is provided between the substrate having the recess and the clamp spring. A mechanical splice characterized by being provided. 2. A V-groove substrate having V-grooves for abutting and supporting opposing optical fibers to position and align each other,
A mechanical splice including a pressing board having a flat surface for pressing the optical fiber inserted in the V groove, and a clamp spring for holding the optical fiber by sandwiching the V groove board and the pressing board. A convex portion extending toward the V-groove substrate and the pressing substrate is formed inside the spring, and a hole having a width narrower than the width of the optical fiber is formed inside at least one of the V-groove substrate and the pressing substrate. A mechanical splice characterized by being formed along the direction.