JP2002267881A - Optical fiber-branched coated optical fiber with multi- fiber optical connector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an action of excessive bending force from being applied to the connector master part of an optical fiber-branched coated optical fiber. SOLUTION: An optical fiber-branched coated optical fiber 1 with a multi-fiber optical connector is directly branched from the opening part of a connector hinder part by making a plurality of optical fibers 11 whose ends are fixed to the ferrule 2 of a fitting pin positioning system into a single core coated optical fiber. The single core coated optical fiber to be directly branched has a tube structure including the optical fibers in which the optical fibers 11 are covered with tubes 12. The group of the tube 12 including the optical fiber (optical fiber-branched coated optical fiber) is adhered and fixed at the connector side (the adhered and fixed part is indicated by 14), at the inner position with a fixed distance from the opening end of a protective boot 9. The region (size b of Figure 1) from the opening end of the protective boot 9 to the adhered and fixed part is present as a region where a little bending of the tube 12 including the optical fiber is tolerated. Accordingly, when bending force acts on the tube 12 including the optical fiber outside the connector, the action of excessive bending force to the connector master part can be prevented, and the occurrence of the bending of the optical fibers 11 which deteriorates transmission characteristics can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber branch core with a multi-core optical connector in which an optical fiber core is branched in a connector.

[0002]

2. Description of the Related Art Conventionally, when an optical fiber fan-out (connecting part) having a multi-core optical connector at one end and a single-core optical connector at the other end is to be constructed, a multi-core optical connector is mounted. In the middle of the optical fiber, the optical fiber is branched into individual optical fibers. That is, as shown in FIG. 8, the optical fiber cord 22 to which the multi-core optical connector 21 is attached is branched (the branch portion is indicated by 23), and the branched single-core optical fiber (or the single-core optical fiber cord) is branched. ) 24 are attached with single-core optical connectors 25 such as SC optical connectors. 22a is an optical fiber ribbon.

[0003]

The above-described conventional branching method uses the branching section 2 reinforced in the middle of the optical fiber cord 22.
3, the space for the branch portion 23 is required, and the structure is not compact. Therefore, in order to make the structure more compact, a structure in which the multi-core optical connector 21 and the branch portion 23 are integrated, that is, each optical fiber is connected to a single-core optical fiber core through an opening at the rear of the multi-core optical connector 21. It is conceivable that the optical fiber is a multi-core optical connector-branched optical fiber directly branched. In this case, as a single-core optical fiber that is directly branched, a structure in which a tube is covered with an optical fiber can be considered. The tube must be fixed to the connector side with an adhesive at the opening at the rear of the connector.

When a single-core optical fiber is directly branched from an opening at the rear of the connector, the separated single-core optical fiber has a reduced rigidity, unlike a taped state. In particular, an excessive bending force is apt to act on the connector mouth portion of the single-core optical fiber cable (near the rear end of the connector), so that the optical fiber is bent at the connector mouth portion and the transmission characteristics are likely to deteriorate. There is a problem. As described above, when the tube is bonded and fixed at the opening at the rear of the connector, if the tube is bonded and fixed at the entire opening up to the opening end face at the rear of the connector, an excessive bending force is applied to the connector opening portion of the optical fiber tube. It is easy to act, and the optical fiber is easily bent to deteriorate the transmission characteristics.

The present invention has been made in view of the above circumstances, and is directed to a case where each optical fiber is directly branched as a single-core optical fiber from an opening at the rear of the connector. When using an optical fiber tube structure, it is possible to prevent the tube from coming off, and at the same time, an excessive bending force acts on the connector opening of the optical fiber tube, causing the optical fiber to bend and the transmission characteristics to deteriorate. It is an object of the present invention to provide an optical fiber branch core cable with a multi-core optical connector without a core.

[0006]

According to a first aspect of the present invention, there is provided an optical connector comprising: a plurality of optical fibers having ends fixed to a fitting pin positioning type ferrule; A protective fiber is attached to the rear end of the connector housing accommodating the ferrule. The rear end portion of the elastic tube to which is attached is bonded and fixed to the optical fiber core group to be branched directly.

According to a second aspect of the present invention, there is provided a multi-fiber optical connector having a plurality of optical fibers each having an end fixed to a fitting pin positioning type ferrule and directly branching from an opening at a rear portion of the connector as optical fiber cores. A fiber branch core,
The optical fiber to be directly branched is bonded and fixed to the connector side at a position within a predetermined distance from the opening end surface of the protective boot attached to the rear end of the connector housing for housing the ferrule. .

According to a third aspect of the present invention, there is provided a multi-fiber optical connector having a plurality of optical fibers, the ends of which are fixed to a ferrule of a fitting pin positioning system, which are directly branched from an opening at a rear portion of the connector as optical fiber cores. A fiber branch core,
An optical fiber cord to be directly branched is formed by covering a tube on an optical fiber, and each optical fiber-containing tube is placed at a fixed distance from an opening end surface of a protective boot attached to a rear end portion of a connector housing containing the ferrule. It is characterized in that it is bonded and fixed to the connector side at the position where it enters.

According to a fourth aspect of the present invention, in the optical fiber branch cable with the multi-core optical connector according to the third aspect, the rear end side of the elastic tube in which the front end side is attached to the rear end of the connector housing in the protective boot is a group of tubes containing optical fibers. And
The optical fiber-containing tube is bonded and fixed to the elastic tube only at the rear end of the elastic tube.

FIG. 1 is a block diagram showing an embodiment of the present invention.
This will be described with reference to FIGS. The present invention relates to a multi-core optical connector-equipped optical fiber branch cable in which a plurality of optical fibers whose ends are fixed to a fitting pin positioning type ferrule are directly branched as single-core optical fiber core wires from an opening at the rear of the connector. It is. FIG. 1 is a cross-sectional plan view showing a portion of a multicore optical connector 10 for branching in an optical fiber branch core 1 with a multicore optical connector according to one embodiment. FIG. 2 is a perspective view showing the general appearance of the multicore optical connector 10 for branching. This multi-core optical connector for branching 10 has a built-in ferrule 2 of a fitting pin positioning system in which 12 optical fibers are internally fixed in one horizontal row. This ferrule 2 is an MT ferrule, that is,
It roughly corresponds to the ferrule of the F12 type multi-core optical fiber connector of JISC5981. The basic structure itself of the multi-core optical connector 10 for branching is equivalent to a general F13 type multi-core optical fiber connector commonly called a so-called MPO optical connector. 1 is slidably stored rearward (right side in FIG. 1) from the position in FIG. 1, and is urged forward (left in FIG. 1) by an internal spring 5 received by a rear housing 4. Note that the connector housing 3 and the rear housing 4 constitute a front part and a rear part of the connector housing in a broad sense. The rear housing 4 is attached to the connector housing 3 with claws 4a fitted into engagement holes 3a provided in the connector housing 3. A coupling 6 is put on the outer periphery of the connector housing 3, and the coupling 6 is urged forward by an external spring 7 arranged between the connector housing 3 and the coupling 6.

A tube 12 is loosely covered with each of the twelve optical fibers 11 whose ends are internally fixed to the ferrule 2 as shown in an enlarged sectional view of FIG. Here, loose refers to a difference between the inner diameter of the tube and the outer diameter of the optical fiber, whereby the optical fiber can bend or move within the tube. The optical fiber 11 housed therein has, for example, an outer diameter of 0.25.
mm. The tube 12 is made of plastic (specifically, made of Hytrel) and has an outer diameter of about 0.9 mm and an inner diameter of 0.5 mm.
mm. The tube (tube with optical fiber) 12 containing the optical fiber 11 forms an optical fiber branch core 13.

As shown in FIGS. 3 to 5, the twelve optical fiber tubes 12 (optical fiber branch cores 13) are attached to elastic tubes (elastic tubes (fiber tubes) 13) attached to the rear outer periphery of the rear housing 4 so as to cover the front end side. For example, the rear end side of the heat-shrinkable tube 8) is covered along the shape of the mounting portion by heat shrinkage. At this time, for example, 2 mm from the rear end of the heat-shrinkable tube 8
The heat-shrinkable tube 8 is covered with the adhesive 14 applied to the outer periphery of the group of optical fiber tubes 12 in a region of an appropriate dimension a (see FIG. 3) such as
2 are bonded and fixed to the heat-shrinkable tube 8, and the optical fiber-containing tubes 12 are bonded and fixed to each other. The adhesive 14 may be, for example, an alpha cyanoacrylate-based instantaneous adhesive. In the illustrated example, the optical fiber-containing tubes 12 are held in a two-dimensional array of three-tiered bales. A flexible protective boot 9 made of an elastic material such as rubber is mounted on the heat-shrinkable tube 8 and at the rear of the rear housing 4.

The vicinity of the rear end of the opening of the protective boot 9 becomes a step 9a as shown in FIG. 3 and becomes narrow, and directly surrounds and holds the optical fiber tube 12 group. Is located at a position close to the step 9a (a distance b from the end face of the protective boot 9 is, for example, 5.3 mm).
Degree position). The area a to be bonded with the adhesive 14 is suitably about 2 mm as described above, but the amount c of the adhesive protruding from the heat-shrinkable tube 8 is desirably kept within about 2 mm. Thus, a certain distance (for example, 3.3 (= b in this example) from the open end face of the protective boot 9
-C) Prevent the adhesive from adhering to the area up to mm).

As described above, the optical fiber tube 1
Since the two groups are elastically wrapped by the heat-shrinkable tube 8 attached to the rear housing 4 and fixed by the adhesive 14, the tube 12 can be reliably prevented from coming off. The group of optical fiber tubes 12 is not fixed to the opening end of the protective boot 9 but is fixed at a position slightly inside from the opening end. 1, the dimension b in FIG. 3) exists as an area where slight bending is allowed. Therefore, when a bending force acts on the optical fiber tube 12 outside the connector, it is possible to prevent a local bending force from acting near the connector mouth (the opening end of the protective boot 9), and the light inside the tube 12 can be prevented. Bending of the fiber 11 can be prevented, and deterioration of transmission characteristics can be prevented. Further, the dispersion of the bending force is also effective in preventing the optical fiber 11 from bending. That is, an external force (bending force) acts on the protective boot 9 first, then acts on the elastic tube 8, and then the tube 12 as an outer peripheral portion of the optical fiber core (in the case of an optical fiber core without using a tube, It acts on a normal optical fiber core wire having a diameter of 0.9 mm, for example, and the bending force diverges in the above order. In this embodiment,
The optical fiber-containing tube 12 is not bonded and fixed directly to the protective boot 9, but only about 2 mm of the end of the heat-shrinkable tube 8 attached to the rear housing 4. It is suitable as a structure that does not apply an excessive bending force to the connector mouth.

In the present invention, the optical fiber 11 is housed in the tube 12 as a single-core optical fiber to be branched. However, this tube structure with the optical fiber has an unreasonable compression on the optical fiber 11 when the connector is connected. This is suitable because no force acts. To explain this, the above-described multi-core optical connector for branching 10 is fitted to the connection adapter 15 shown in FIG. )
Connect with At the time of this connector mating operation (at the time of connection operation)
In addition, the front end engaging projection 6a of the coupling 6 is
The ferrule 2 contacts the ferrule of the mating multi-core optical connector fitted to the adapter 15 from the opposite side and is pushed, and receives the reaction force of the internal spring 5 in FIG. Step back slightly to the right. At this time, the optical fiber 11 whose end is fixed to the receding ferrule 2
Is loosely housed in the tube 12 and is not restrained, so there is no need to absorb the retreat of the ferrule 2 only in the internal space of the optical connector, and in particular, no compressive force acts. Therefore, there is no possibility that the optical fiber 11 will be locally bent in the optical connector and the transmission characteristics will be degraded.
That is, the retracted length of the ferrule is absorbed by the movement of the optical fiber inside the loose tube inside and outside the optical connector.

In the embodiment, the optical fiber tube 12
Although the group is held by the heat-shrinkable tube 8, the optical fiber-containing tube 12 may be directly adhered and fixed to the inner surface of the protective boot 9. In this case, it is preferable not to adhere and fix the protective boot 9 from the open end to, for example, about 3 mm. Further, the mode of holding the group of optical fiber tubes 12 is not limited to the bale stacking arrangement shown in the drawing, but may be held in another bale stacking arrangement, or may be held in a single horizontal row arrangement. . Further, in the embodiment, the tube (tube with optical fiber) 12 is fixed to the heat-shrinkable tube 8, but an optical fiber core wire having a certain thickness may be directly bonded and fixed to the heat-shrinkable tube. A single-core optical connector is attached to the end of the single-core branched optical fiber, or a single-core optical connector is provided as it is, or a fusion spliced portion with another optical fiber is provided.

[0016]

According to the optical fiber branch cable with the multi-core optical connector of the present invention, a protective boot is mounted on the rear end of the connector housing for accommodating the ferrule. Since the rear end of the elastic tube to which the front end is attached is bonded and fixed to the optical fiber core group for directly branching, an excessive bending force acts on the connector mouth portion of the optical fiber branch core. Thus, it is possible to prevent the transmission characteristics from deteriorating due to bending of the optical fiber.

According to the second and third aspects of the present invention, the optical fiber to be directly branched (optical fiber branch) is:
It is glued and fixed to the connector side at a fixed distance from the opening end of the protective boot, so similarly, it is possible to prevent excessive bending force from acting on the connector mouth of the optical fiber branch cable. In addition, it is possible to prevent the transmission characteristics from deteriorating due to bending of the optical fiber.

According to a fourth aspect of the present invention, the elastic tube having the front end attached to the connector housing is put on the optical fiber tube group, and the optical fiber tube is bonded and fixed to the elastic tube only at the rear end of the elastic tube. The configuration is appropriate as a structure that does not apply an excessive bending force to the connector mouth portion of the optical fiber tube.

[Brief description of the drawings]

FIG. 1 is a plan sectional view of a portion of a multi-core optical connector for branching in a multi-core optical fiber with a multi-core optical connector according to an embodiment of the present invention.

FIG. 2 is a perspective view of the branching multi-core optical connector portion and the connection adapter.

FIG. 3 is an enlarged view of a main part of FIG. 1;

FIG. 4 is a sectional view taken along line AA of FIG. 3;

FIG. 5 is a sectional view taken along line BB of FIG. 3;

FIG. 6 is a sectional view taken along the line CC of FIG. 3;

FIG. 7 is an enlarged cross-sectional view of one optical fiber branch core in the optical fiber branch core with a multi-core optical connector.

FIG. 8 is an explanatory diagram of a configuration of a conventional optical fiber branch cable with a multi-core optical connector.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Multi-core optical connector for branching 2 Ferrule 3 Connector housing 4 Rear housing 8 Shrinkable tube (elastic tube) 9 Protective boot 9a Stepped portion 10 Optical fiber branch core wire with multi-core optical connector 11 Optical fiber (optical fiber wire) 12 tube 13 Optical fiber branch core wire 14 Adhesive

Claims (4)

[Claims] An optical fiber with a multi-fiber optical connector, wherein a plurality of optical fibers whose ends are fixed to a ferrule of a fitting pin positioning type are directly branched from an opening at a rear portion of the connector as an optical fiber. A protective boot is attached to the rear end of the connector housing that houses the ferrule, and a light for directly branching the rear end of the elastic tube having the front end attached to the rear of the connector housing in the protective boot. An optical fiber branch cable with a multi-core optical connector, which is bonded and fixed to a fiber core group. 2. A multi-fiber optical connector-equipped optical fiber branch having a plurality of optical fibers whose ends are fixed to a fitting pin positioning type ferrule and directly branched from an opening at the rear of the connector as optical fiber cores. The optical fiber cord to be directly branched is bonded and fixed to the connector side at a position within a predetermined distance from the opening end face of the protective boot attached to the rear end of the connector housing for housing the ferrule. Characteristic optical fiber branch cable with multi-core optical connector. 3. A multi-fiber optical connector-equipped optical fiber branch having a plurality of optical fibers whose ends are fixed to a ferrule of a fitting pin positioning method and which is directly branched from an opening at the rear of the connector as an optical fiber. An optical fiber core to be directly branched is formed by covering a tube with an optical fiber, and each optical fiber-containing tube is fixed at a predetermined distance from an opening end surface of a protective boot attached to a rear end of a connector housing for housing the ferrule. An optical fiber branch core cable with a multi-core optical connector characterized in that it is adhesively fixed to the connector only at the position where it enters. 4. A rear end side of an elastic tube having a front end attached to a rear portion of a connector housing in the protective boot, and a rear end side of the elastic tube is put on the optical fiber tube group. 4. An optical fiber branch cable with a multi-core optical connector according to claim 3, wherein the optical fiber branch cable is bonded and fixed to an elastic tube.