JP2001201668A - Mechanical splice - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive mechanical splice capable of securely clamping the whole body even if an object to be clamped is a multiple optical fiber. SOLUTION: Projected parts 11 extending to the side of a V groove substrate 4 and the side of a pressing substrate 5 are formed in the inside of a clamp spring 6, a recessed part 12 having the width narrower than the width of the optical fiber 2 is formed along the optical axis over part or the whole of the surface opposite to the surface coming into contact with the inserted optical fiber 2 of at least one of the V groove substrate 4 and the pressing substrate 5, and a planar spacer substrate 14 is provided between the substrates 4, 5 in which the recessed part 12 is formed and the clamp spring 6.

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 fibers.

[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have become the mainstream of transmission lines, and most of middle- and long-distance trunk lines have already been replaced by optical fiber cables from conventional metal cables. Further, several years later, efforts are being made at a rapid pace to realize an optical subscriber transmission system in which a line to each home is converted to an optical fiber.

[0003] Splicing of optical fibers has been conventionally performed. Fusion splicing is highly reliable because it melts the butted surface of the optical fiber to make the connection, but on the other hand, it takes time to reinforce after the connection, the equipment is expensive, and the power supply is required. Had become.

Therefore, a mechanical splice as disclosed in Japanese Patent Application Laid-Open No. 9-318836 has been devised, which is designed to easily connect an optical fiber by aligning the optical fiber with a V-groove or the like and fixing the optical fiber. ing. This mechanical splice is expected to reduce the cost of connection because of its simple structure and connection method.

As shown in FIG. 5, a conventional mechanical splice 51 includes a V-groove substrate 55 in which a V-groove 54 for aligning a core 53 of an optical fiber 52 is formed, and a core 53 from above. Holding substrate 56 that holds down and fixes
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, a wedge 59 is inserted into a wedge insertion groove 58 between the V-groove substrate 55 and the holding substrate 56 to spread it out, and the optical fiber 52 is inserted into the gap from both ends. After the core wires 53 are butted against each other, the wedge 59 is pulled out, and the positioning and holding of the optical fiber 52 in the V-groove 54 are performed by the restoring force of the clamp spring 57.

The mechanical splice 5 shown in FIG.
1 is for a single core, but there is also a mechanical splice 61 for a four core as shown in FIG. The mechanical splice 61 is formed with four rows of V grooves 62, and each core 63 is inserted into each V groove 62.

[0008]

By the way, in recent years, a cable using an eight-core optical fiber has been often used for a main trunk line or the like due to an increase in the amount of information. Therefore, 8
A mechanical splice for the heart has become necessary.

Therefore, the present inventors have proposed a method as shown in FIG.
It has the same structure as the mechanical splice 61 for 4 cores,
A mechanical splice 65 in which eight rows of grooves 64 were formed was prototyped.

However, in the mechanical splice 65 described above, the resin is used for the V-groove substrate 67 and the holding substrate 68 in order to reduce the cost, so that the rigidity is not high.

Therefore, the V-groove substrate 67 and the holding substrate 6
8 are warped on both sides in the width direction.
Although the core wire 72a located within the width of the convex portion 71 of No. 9 can be reliably gripped, no force is applied to the outer core wire 72b, gripping becomes insufficient, and when subjected to a temperature cycle, There is a problem in that a gap is generated in the abutting portion of the optical fiber to increase the connection loss, and that the connection loss is large due to 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 completely match. Otherwise, the convex portion 71 of the clamp spring 69
It has been found that the V-groove substrate 67 and the holding substrate 68 are in a one-sided contact state, and that the gripping force of the optical fiber varies. Therefore, there has been a problem that the manufacturing accuracy of the mechanical splice 65 must be increased, which leads to an increase in cost.

Accordingly, the present invention has been devised in order to solve the above-mentioned problem, and an object of the present invention is to provide a mechanical splice which can securely hold the entirety of a multi-core optical fiber at low cost. To provide.

[0014]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a V-groove substrate having a V-groove for abutting and supporting opposing optical fibers and positioning and aligning them. In a mechanical splice having a holding substrate having a flat surface for holding the inserted optical fiber, and a clamp spring for holding the optical fiber by holding the V-groove substrate and the holding substrate, the inside of the clamp spring Forming a convex portion extending to the V-groove substrate and the holding substrate side, at least one of the V-groove substrate and the holding substrate, on the surface opposite to the surface in contact with the inserted optical fiber,
A concave portion having a width smaller than the width of the optical fiber is formed over part or all of the concave portion along the optical axis direction, and a flat spacer substrate is provided between the substrate having the concave portion and the clamp spring. It is provided.

According to the above configuration, the clamping force of the clamp spring is transmitted to the outside in the width direction of the V-groove substrate or the pressing substrate via the spacer substrate. Even in the case where the number of core wires of the fiber is large, the fiber can be uniformly and reliably held to the outside in the width direction. Further, the manufacturing accuracy may be equal to the conventional one, so that an increase in cost can be prevented.

Further, the present invention has a V-groove substrate having a V-groove for abutting and aligning and aligning opposing optical fibers, and a flat surface for holding the optical fiber inserted in the V-groove. In a mechanical splice having a holding substrate and a clamp spring for holding the optical fiber by sandwiching the V-groove substrate and the holding substrate, a protrusion extending toward the V-groove substrate and the holding substrate inside the clamp spring. A hole having a width smaller than the width of the optical fiber is formed in at least one of the V-groove substrate and the holding substrate along the optical axis direction.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One preferred embodiment of 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 the 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 butt-connecting an optical fiber 2 by inserting the optical fiber 2 from opposite sides and supporting and aligning the optical fiber 2. A V-shaped grooved substrate 4 having a V-shaped groove 3 having a substantially V-shaped cross section, and a holding substrate 5 which is superposed on the V-shaped grooved substrate 4 and has a flat surface for holding the optical fiber 2 inserted into the V-shaped groove 3. , A clamp spring 6 having a U-shaped cross section for gripping the optical fiber 2 by sandwiching the V-groove substrate 4 and the holding substrate 5.

Inside the clamp spring 6, a V-groove substrate 4 and a convex portion 11 extending to the holding substrate side 5 are formed. The protrusions 11 are formed by extruding the clamp spring 6 into a circle at predetermined intervals in the longitudinal direction.

The holding substrate 5 is divided into a portion for holding the exposed core wire 7 by stripping the optical fiber 2 and a portion not to be stripped, and is integrally supported by the clamp spring 6. Have been.

The V-grooves 3 are formed along the longitudinal direction of the V-groove substrate 4 as many as the number of core wires 7 of the optical fiber 2 to be abutted (eight in this case). The longitudinal center portion of the V-groove 3 is formed to have a depth and a width substantially equal to those of the core wire 7 so that the optical fibers 2 inserted from both sides are aligned and abutted. On the other hand, both ends in the longitudinal direction of the V-groove 3 are formed deeper than the center portion, and the connection portion is formed in a tapered shape and connected.

The 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 at the overlapping portion of the V-groove substrate 4 and the holding substrate 5, and the wedge insertion groove 8 has a wedge (not shown). 3), the clamp spring 6 is inserted.
Open the V-groove substrate 4 and the holding substrate 5 against the spring force of
A gap is formed. The optical fiber 2 having been subjected to terminal treatment is inserted into the gap from both ends, and after the cores 7 are abutted in the V-groove 3, the wedge is removed and the optical fiber 2 is removed.
Is held and fixed / connected by the V-groove substrate 4 and the holding substrate 5. The optical fiber 2 is abutted at a substantially central portion in the longitudinal direction of the V-groove substrate 4.

According to the present invention, at least one of the V-groove substrate 4 and the holding substrate 5 has a width smaller than the width of the optical fiber 2 on the surface opposite to the surface in contact with the inserted optical fiber 2. The recessed part 12 is formed along the optical axis direction over a part or the whole thereof, and the flat plate-shaped spacer substrate 1 is provided between the substrate having the recessed part 12 and the clamp spring 6.
4 is provided.

In this embodiment, a case where the depression 12 is formed in the holding substrate 5 will be described.

In this case, the holding substrate 5 is formed to be half the thickness of the conventional one. The above-described recess 12 is formed on the upper surface opposite to the plane for holding the optical fiber 2.
Are formed at substantially the center in the width direction.

The concave portion 12 is formed over the entire length of the holding substrate 5 located at a portion where the core wire 7 is held. Note that the concave portion 12 may be formed partially in accordance with the position of the convex portion 11 of the clamp spring 6.

A spacer substrate 14 having a thickness equivalent to that of the holding substrate 5 is provided on the holding substrate 5. The spacer substrate 14 is formed in a flat plate shape having the same width and length as the holding substrate 5, and the lower surface of the spacer substrate 14 and the upper surface of the holding substrate 5 are in surface contact. Note that the upper surface, which is on the far side (left side in the figure) with respect to the clamp spring 6, is chamfered.

Next, the operation of the mechanical splice 1 having the above configuration 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 holding substrate 5 via the spacer substrate 14.

At this time, at the center of the pressing substrate 5 in the width direction,
The provision of the concave portion 12 causes the clamping force to be transmitted from the spacer substrate 14 to the outside of the pressing substrate 5 in the width direction. As a result, both outer sides of the holding substrate 5 are urged downward, so that the outer sides do not warp upward.

Therefore, the flat surface on the lower side of the holding substrate 5 is kept flat, the core wire 7 of the optical fiber 2 can be held uniformly, and the holding can be surely performed. Therefore,
Even when subjected to a temperature cycle, no gap is generated at the butted portion of the optical fibers, and an increase in connection loss can be reduced.

More specifically, 20 mechanical splices 1 for 8 cores were manufactured, and a temperature cycle test of 10 cycles was performed at -40 to 70 ° C./6h for 1 cycle. While the mechanical splice 65 for an eight-core fiber had a loss increase of 0.3 dB or more, the mechanical splice 1 of the present invention obtained a favorable result that the loss increase was 0.1 dB or less.

The holding substrate 5 has a thickness half that of the conventional one, and a spacer substrate 14 equivalent to the thickness of the holding substrate 5 is provided on the holding substrate 5. The clamp force of the clamp spring 6 is transmitted to the core wire 7 in a well-balanced manner, and the gripping force can be effectively kept large.

Further, according to the present invention, the V-groove substrate 4, the holding substrate 5, and the spacer substrate 14 can be manufactured with the same inexpensive resin as the conventional one, and the manufacturing accuracy can be the same as the conventional one. 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 has a holding substrate 22 in which a hole 23 having a width smaller than the width of the optical fiber 2 is formed along the optical axis direction. is there. The hole 23 is formed so as to penetrate substantially the center of the pressing substrate 22 in the width direction and the thickness direction, and is positioned above the substantially center of the V groove 3 in the width direction.

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

The other parts are the same as those of the mechanical splice 1 shown in FIG.

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

At this time, by providing the holes 23 in the holding substrate 5, the clamping force is dispersed and transmitted to the outside of the holes 23 in the center of the holding substrate 5 in the thickness direction, and is transmitted to the lower flat surface. It is transmitted. Therefore, both outer sides of the holding substrate 5 are urged downward, and the outer sides do not warp upward.

Therefore, the mechanical splice 1 shown in FIG.
The same operation and effect as described above can be obtained.

In the above embodiment, the recess 12 or the hole 23 is formed on the side of the holding substrate 5, 22. However, the present 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.
In addition, the concave portions 1 are formed in both the V-groove substrate 4 and the holding substrates 5 and 22.
2 or a hole 23 may be formed.

In the above embodiment, the V-shaped groove 3
Are formed in eight rows, but are not limited to this. When connecting an optical fiber having a larger number of cores, V-grooves may be provided for the number of the cores.

[0047]

In summary, according to the present invention, since the V-groove substrate or the holding substrate does not warp, even if the optical fiber is a multi-core optical fiber, the entirety can be securely gripped and a low-cost material can be used. Can manufacture V-groove substrates, holding substrates, etc.
Further, since the manufacturing accuracy may be the same as the conventional one, an excellent effect that cost increase can be prevented is exhibited.

[Brief description of the drawings]

FIG. 1 is a 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 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 prototype mechanical splice of a prototype.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 mechanical splice 2 optical fiber 3 V groove 4 V groove substrate 5 holding substrate 6 clamp spring 11 convex portion 12 concave portion 14 spacer substrate 21 mechanical splice 22 holding substrate 23 hole

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Yoshihiro Nakatani 5-1-1, Hidaka-cho, Hitachi City, Ibaraki Prefecture Inside the Opto-System Laboratory, Hitachi Cable, Ltd. (72) Hidekazu Abe Hidaka-cho, Hitachi City, Ibaraki Prefecture 5-1-1, Hitachi Cable, Ltd. Opto-System Research Laboratory (72) Inventor Masaaki Takaya 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 F-term (reference) 2H036 LA03 LA08 NA01

Claims (2)

[Claims] 1. A V-groove substrate having a V-groove for abutting and supporting opposing optical fibers and aligning and positioning them.
A mechanical splice comprising: a holding substrate having a flat surface for holding the optical fiber inserted into the V-groove; and a clamp spring for holding the optical fiber by holding the V-groove substrate and the holding substrate. A convex portion extending toward the V-groove substrate and the holding substrate is formed inside a spring, and at least one of the V-groove substrate and the holding substrate, on a surface opposite to a surface in contact with the inserted optical fiber,
A concave portion having a width smaller than the width of the optical fiber is formed over part or all of the concave portion along the optical axis direction, and a flat spacer substrate is provided between the substrate having the concave portion and the clamp spring. A mechanical splice characterized by being provided. 2. A V-groove substrate having a V-groove for supporting and aligning and positioning opposing optical fibers against each other,
A mechanical splice comprising: a holding substrate having a flat surface for holding the optical fiber inserted into the V-groove; and a clamp spring for holding the optical fiber by holding the V-groove substrate and the holding substrate. A convex portion extending toward the V-groove substrate and the holding substrate is formed inside the spring, and a hole having a width smaller than the width of the optical fiber is formed in at least one of the V-groove substrate and the holding substrate. A mechanical splice formed along a direction.