JP2002022996A - Mechanical splice - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mechanical splice that can prevent the surface of a guide groove from being scraped off by the tip end of a coated optical fiber in inserting an optical fiber and that, therefore, can reduce connecting loss. SOLUTION: The mechanical splice 20 is equipped with a V-grooved base plate 21 which is provided with an aligning mechanism for positioning and aligning the optical axes of the optical fibers, with the purpose of connecting these optical fibers having one or more coated fibers a, by butting them against each other, equipped with a holding base plate 22 which holds the optical fibers inserted into the V-grooved base plate 21, and also equipped with a U-shaped clamp spring 23 which clamps the optical fibers abutted by the V-grooved base plate 21 and by the holding base plate 22. In this mechanical splice 20, a guide groove 27 is provided in the V-grooved base plate 21 for the purpose of guiding the optical fibers to be inserted and abutted for connection to the aligning mechanism. In addition, in a part or all of the guide groove 27, a coating layer 29 is formed composed of a material harder than that of the guide groove 27.

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have become the mainstream of transmission lines, and most of middle- and long-distance trunk lines have already been replaced by optical fiber cables from conventional metal cables.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

[0003] Splicing of optical fibers has been conventionally performed. Fusion splicing is highly reliable because it melts the butted surface of the optical fiber for connection.However, it requires time for reinforcement after connection, expensive equipment, and the need for a power supply. Had become.

[0004] Therefore, a mechanical splice has been devised to easily connect the optical fiber by aligning and fixing the optical fiber by a centering mechanism such as a V-groove or the like, and its development has been advanced (for example, Japanese Patent Laid-Open No. Hei 8-234037). JP-A-9-73023, JP-A-9-90148, JP-A-9-96733, JP-A-9-318836, etc.).

[0005] Above all, the mechanical splice disclosed in Japanese Patent Application Laid-Open No. 9-318836 is expected to reduce the cost of connection because of its simple structure and connection method.

Such a mechanical splice is shown in FIG.
This will be described with reference to FIG.

FIGS. 5 and 6 show a single-core mechanical splice for connecting optical fibers having one core, and FIGS. 7 and 8 show a four-core mechanical splice.
4 shows a four-core mechanical splice for connecting optical fibers.

Single core mechanical splices 30 and 4
The mechanical splice for core 40 has the same basic configuration, and has V-groove substrates 31 and 4 having V-grooves 36 and 46 which are alignment mechanisms for positioning and aligning the optical axis of the optical fiber.
1, holding substrates 32 and 42 for holding the optical fibers inserted in the V-groove substrates 31 and 41, and a V-groove substrate 3
Clamp springs 33, 43 for sandwiching the holding substrates 32, 42 from above and below to generate a clamping force.
It is roughly composed of

As shown in FIGS. 6 and 8, the single-core mechanical splice 30 and the four-core mechanical splice 40 are connected between V-groove substrates 31 and 41 and holding substrates 32 and 42, respectively. Slit 34,4
4, a wedge 50 is inserted to leave a gap, and the optical fibers 10, 10 whose terminal wires are exposed and whose core wires 11 are exposed, are inserted and butted from both ends, and then the wedge 50 is removed and the clamp springs 33, 43 are removed. The optical fibers 10, 10 are positioned and gripped by the restoring force.

A single-core mechanical splice 30 has a V-groove substrate 31 and an optical fiber insertion port 35 at both ends of a holding substrate 32 which are formed in a conical shape. It is guided by a V-groove 36 formed in the center of the splice 30.

The four-core mechanical splice 40 is provided with a guide groove 47 for guiding the optical fiber 10 and the core wire 11 to the V groove 46 on the longitudinal extension of the V groove 46 of the V groove substrate 41. The optical fiber 10 and the core 11 are inserted into the guide groove 47.

The size of the mechanical splices 30, 40 is 4 mm × about the same size as the reinforcing member used for fusion splicing.
The size of 4 mm x 40 mm is used for common storage and the like after connection. To date, single-core and 4-core mechanical splices have been developed.

On the other hand, an optical fiber having eight cores is used for a main trunk line or the like due to an increase in information amount, and a mechanical splice for eight cores is required.

[0014] The mechanical splice for the 8-core is 4
The V-groove substrate 41 has the same shape as that of the mechanical splice 40, and has eight V-grooves 46 and eight guide grooves 47 formed on the V-groove substrate 41.

[0015]

However, an eight-core optical fiber has a higher bending rigidity than a four-core optical fiber.
When the core of the optical fiber is aligned with the guide groove, a large force is applied to a portion where the core and the guide groove are in contact.

In order to reduce the cost, the mechanical splice uses a resin molded product except for the clamp spring, and since the tip of the core wire is a surface obtained by cutting glass at a right angle, the mechanical splice is If a large force is applied to the portion in contact with the guide groove, the tip of the core wire may cut the surface of the guide groove during the insertion process, and the shaved residue may have the following effects.

(1) The optical path adheres to the core on the end face of the optical fiber to block the optical path.

(2) There is an interval between the abutting portions of the core wires.

(3) The optical axis is shifted between the V-groove and the core wire.

For this reason, the conventional mechanical splice has a problem that the connection loss increases.

An object of the present invention is to solve the above-mentioned problems and to provide a mechanical splice which can prevent the surface of the guide groove from being cut off by the tip of the optical fiber when inserting the optical fiber and has a small connection loss.

[0022]

SUMMARY OF THE INVENTION In order to achieve the above object, the invention according to claim 1 is directed to butt-connecting optical fibers having one or a plurality of core wires so as to face each other.
A V-groove substrate having an alignment mechanism for positioning and aligning the optical axis of the optical fiber, a holding substrate for holding the optical fiber inserted into the V-groove substrate, and the V-groove substrate and the holding substrate. A guide for guiding an optical fiber inserted and butt-connected to the V-groove substrate to the centering mechanism in a mechanical splice having a U-shaped clamp spring for holding the butted optical fiber. A mechanical splice in which a groove is provided and a coating layer made of a material harder than the material of the guide groove is formed on part or all of the guide groove.

According to the above configuration, since the surface of the guide groove is formed of a material having a high hardness, it is possible to prevent the tip of the core wire from shaving off the surface of the guide groove at the time of insertion, and to perform connection by the influence of shavings. An increase in loss can be prevented.

The material of the coating layer formed in the guide groove is silicon (Si), silicon carbide (SiC), silicon nitride (Si ₃ N ₄ ), alumina (Al ₂ O ₃ ), and glass (SiO ₂ ). Either one may be used.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view showing a V-groove substrate of the mechanical splice of the present embodiment, FIG. 2 is an enlarged partial sectional view of a portion A in FIG. 1, and FIG. 3 is a perspective view of the mechanical splice. FIG. 4 is a perspective view showing a method for connecting an optical fiber of a mechanical splice according to the present embodiment.

As shown in FIG. 3, the mechanical splice 20 includes a V-groove substrate 21 having a V-groove 26 as an alignment mechanism for aligning and aligning the optical axis of an optical fiber,
A holding substrate 22 for holding the optical fibers 10 and 10 inserted in the groove substrate 21 and a clamp spring 23 for holding the V-groove substrate 21 and the holding substrate 22 from above and below to hold the optical fiber 10 are schematically constituted. You.

As shown in FIG. 1, the V-groove 26 extends in the longitudinal direction substantially at the center of the V-groove substrate 21.

The V-groove 26 is used to connect the optical fiber 10 to be connected.
The same number or more than the number of core wires 11 (eight in this embodiment) are formed, and the optical fibers 10 to be connected are
The ten core wires 11 are inserted into the V-groove 26 and positioned and centered on the basis of the outer diameter of each core wire 11.

The cores 11 of the optical fibers 10, which are inserted into the V-groove substrate 21 and butt-connected, are placed on the V-groove 26 along the longitudinal extension of each V-groove 26 of the V-groove substrate 21.
A guide groove 27 for guiding the wire is provided, and the respective core wires 11 are inserted along the guide groove 27 and guided to the V groove 26.

As shown in FIG. 2, on the surface of the guide groove 27, a coating layer 29 made of a material harder than the resin that is the material of the V-groove substrate 21 is formed.

In the present embodiment, the coating layer 29 is
Silicon (Si) is 0.2 to 0.3 μm by vacuum evaporation
It was formed by coating.

As shown in FIG. 3, the holding substrate 22 of the present embodiment has a three-part structure, and engages with a groove 23a formed in the clamp spring 23 to adjust its position. It has a projection 22a for matching.

Next, the operation of the present invention will be described.

As shown in FIG. 4, a wedge 50 is inserted into a slit 24 formed between the V-groove substrate 21 and the holding substrate 22 of the mechanical splice 20 to form a gap, and the tape is processed by terminal processing. The optical fibers 10 with the exposed wires 11 are inserted from both ends of the mechanical splice 20.

At the time of insertion, the optical fiber ribbons 11 of the optical fibers 10 are inserted along the guide grooves 27 of the V-groove substrate 21.

At this time, a large force is applied to the portion where the tape core wires 11 and 11 and the guide groove 27 are in contact with each other, but the surface of the guide groove 27 is made of a material harder than the resin used as the material of the V-groove substrate 21. Since the coating layer 29 made of silicon is formed, the surface of the guide groove 27 is
It will not be scraped off by the tip.

After that, the wedge 50 is pulled out, and the optical fibers 10, 10 are positioned and gripped by the restoring force of the clamp spring 23.

When the optical fibers 10, 10 are inserted, the tape cores 11, 11 do not scrape the surface of the guide groove 27, so that no shavings are generated.

As a result, the shavings do not exert the following effects.

(1) The optical path adheres to the core on the end face of the optical fiber and interrupts the optical path.

(2) There is an interval between the abutting portions of the core wires.

(3) The optical axis is shifted between the V groove and the core wire.

Therefore, the connection loss when connecting the optical fiber is reduced.

Specifically, connection loss was measured by preparing 30 samples of the mechanical splice 20 of the present embodiment and 30 samples of the conventional mechanical splice for eight cores, respectively. As a result, the connection loss of the conventional mechanical splice was reduced.
While three things that exceeded 0.5dB occurred,
In the mechanical splice 20 of the present embodiment, the connection loss
None exceeded 0.5 dB.

Although the material of the V-groove 26 of the V-groove substrate 21 is also resin, a refractive index matching agent is applied to the V-groove 26 to reduce reflection after butt connection. Since the agent also serves as a lubricant, shaving by the ends of the core wires 11 does not occur.

In the present embodiment, the coating layer has been described as being coated with silicon (Si) by 0.2 to 0.3 μm by vacuum deposition, but the present invention is not limited in this respect, and other materials and methods may be used. Is also good.

For example, the material of the coating layer may be silicon carbide (SiC), silicon nitride (Si ₃ N ₄ ), alumina (Al ₂ O ₃ ), glass (SiO ₂ ), or the like.

The coating layer 29 is formed in the guide groove 1
7 may be formed, or the guide groove 27 may be formed.
It may be formed in a part other than the above.

Further, in the present embodiment, the mechanical splice 20 has been described and illustrated as having eight cores. However, the present invention is not limited to this point, and is applicable to a mechanical splice or the like for connecting a single-core or four-core optical fiber. It can also be applied.

[0051]

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

(1) When the optical fiber is inserted, no shaving is caused by the tip of the core wire.

(2) Connection loss is small.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a V-groove substrate of a mechanical splice of the present invention.

FIG. 2 is an enlarged partial sectional view of a portion A in FIG.

FIG. 3 is a perspective view of a mechanical splice of the present invention.

FIG. 4 is a perspective view showing a method for connecting an optical fiber to a mechanical splice according to the present invention.

FIG. 5 is a perspective view of a conventional single-core mechanical splice.

FIG. 6 is a perspective view showing a conventional optical fiber connecting method for a single-core mechanical splice.

FIG. 7 is a perspective view of a conventional four-core mechanical splice.

FIG. 8 is a perspective view showing a conventional optical fiber connection method for a four-core mechanical splice.

[Explanation of symbols]

 Reference Signs List 20 mechanical splice 21 V-groove substrate 22 holding substrate 23 clamp spring 27 guide groove 29 coating layer

 ──────────────────────────────────────────────────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 Shinji Nagasawa Tokyo 2-3-1 Otemachi, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation F-term (reference) 2H036 JA02 LA03 LA05 LA08 MA01 NA01

Claims (2)

[Claims] A V-groove substrate having a centering mechanism for positioning and aligning an optical axis of the optical fiber so that optical fibers having one or a plurality of optical fibers are opposed to each other and butt-connected; In a mechanical splice having a holding substrate for holding the optical fiber inserted into the V-groove substrate and a U-shaped clamp spring for holding the optical fiber abutted between the V-groove substrate and the holding substrate, The V-groove substrate is provided with a guide groove for guiding the optical fiber to be inserted and butt-connected to the alignment mechanism, and part or all of the guide groove is provided.
A mechanical splice, wherein a coating layer made of a material harder than the material of the guide groove is formed. 2. The material of the coating layer formed in the guide groove is silicon (Si), silicon carbide (SiC), silicon nitride (Si ₃ N ₄ ), alumina (Al ₂ O ₃ ), and glass (SiO ₂ ). The mechanical splice according to claim 1, which is any one of the above.