JPH0862459A - Single coated optical fiber - Google Patents

Abstract

PURPOSE: To provide a single coated optical fiber having good workability at the time of connection and excellent in the handling characteristic at a junction at a low cost by applying a concentric cover with a ultraviolet-ray hardening resin on the outside of a strand having the same cover material and outer diameter as those of an optical fiber core in an optical fiber tape into a specific outer diameter. CONSTITUTION: A concentric coating 19 is applied with a ultraviolet-ray hardening resin on the outside of a core having the same coating material and outer diameter as those of an optical fiber core 12 in an optical fiber tape 7 to form a single coated optical fiber having the outer diameter of 0.6mm or above. When the single coated optical fibers are to be connected to the optical fiber tape 7, only the outside coatings 19 of the cores 12 are removed by 15cm or above with a simple tool. The same number of single coated optical fibers as the cores of the optical fiber tape 7 are linearly aligned, portions 13 of the optical fiber cores 12 are linearly aligned and fixed with no gap, thus they can be easily connected to the optical fiber tape 7, and the handling characteristic is improved because the outer diameter of each core is made 0.6mm or above.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single-core coated optical fiber in an optical fiber cable which is mainly used for constructing an optical fiber network for optical communication.

[0002]

2. Description of the Related Art In future telecommunications, it is assumed that, in addition to telephone services, intelligent services using computers and high-performance telephones, video communication services such as high-definition televisions or videophones will spread. In order to provide such a service, it is important to introduce an optical fiber having the characteristics of low loss and wide band into the subscriber line network. For this reason, research and development for constructing and maintaining the subscriber optical fiber network are actively underway.

First, FIG. 1 shows the equipment configuration of a subscriber system.
1 is an intra-station transmission device, 2 is an optical fiber cable terminal rack, 3
Is a subscriber transmission device, 4 is an outdoor transmission device, 5 is an optical fiber cable, 6 is a metal cable or a coaxial cable. In the subscriber system, there is an intra-station transmission device 1 in the telephone station,
Optical signals are transmitted between the subscriber transmission device 3 or the outdoor transmission device 4 via the plurality of optical fiber cables 5. When the transmission device is located outdoors, the signal is transmitted to the terminal by the metal cable or the coaxial cable 6. To construct a subscriber optical line, a plurality of optical fiber cables are connected in this way, branched at a connection point in the middle, and finally one or two optical fibers are wired to the subscriber. It

A multi-fiber, high-density optical fiber cable is required between the telephone station and this branch point, and an optical fiber cable having a structure as shown in FIG. 2 is used. FIG. 2a is a cross-sectional view of the cable, in which 7 is a 4-fiber optical fiber tape, 8 is an optical fiber cable jacket, 9 is a center tension member, 10 is a slot rod, and 11 is a copper wire for a meeting at the time of construction. 2b is a sectional view of the optical fiber tape 7, in which 12 is an optical fiber, 13 is a concentric coating on the outer circumference of the optical fiber, and 14 is a collective coating. The optical fiber cable of FIG. 2 has a structure in which a plurality of optical fiber tapes 7 are stacked and tightly accommodated in a groove (slot) provided in a spiral shape on the outer circumference of the plastic rod 10 in advance. This is 3
It is an example of a 00-core optical fiber cable.

As shown in FIG. 2b, the optical fiber tape 7
Is a structure in which a plurality of optical fiber element wires, each of which has a coating 13 concentrically formed on the outer circumference of the optical fiber 12, are arranged linearly and are collectively coated. Usually, the outer diameter of the optical fiber is 0.25 mm,
A large number of four-core optical fiber tapes or eight-core optical fiber tapes are mounted in order to realize a high-density optical fiber cable of several hundreds to thousands. Further, an ultraviolet curable resin is used as a coating material for the optical fiber tape. The features of the optical fiber cable of this structure are that it uses an optical fiber tape to enable multi-core batch connection, good connection efficiency, high density and multiple cores,
It is easy to take out the optical fiber tape when connecting the optical fiber.

However, in order to wire one or two optical fibers to a subscriber, the optical fiber tape is the minimum wiring unit at a branch point in the middle of the optical line or a drop point immediately before being pulled into the subscriber's house. That is, it is necessary to use one or two optical fibers. As this method, a method of separating an optical fiber tape into a coated optical fiber of a minimum wiring unit or a method of converting to a minimum wiring unit using a core number conversion code is used.

[0007]

However, in the former method, since the optical fiber tape cannot be easily separated into the minimum wiring unit, it takes a lot of time for this separation work, and the coating after separating the optical fiber tape is performed. Since the optical fiber becomes thin, there is a problem that workability at the time of connection is significantly deteriorated. In the latter method, a core number conversion code as shown in FIG. 3 is used. In the figure, 15 is a multi-fiber optical connector plug, 16 is an optical fiber tape separating section, 17 is a single fiber optical connector, and 18 is a single fiber coated optical fiber. However, this core number conversion cord is expensive because it is poor in manufacturability and the number of optical connectors attached to both ends of the cord is large, and the number of connection points is increased by using the core number conversion cord. There is a problem in that the workability is not good because the connection loss of 1) occurs, and the connection part including the core number conversion code needs to be housed in a closure or a cabinet.

Therefore, an object of the present invention is to provide a single-core coated optical fiber which is low in cost, can be connected with an optical fiber tape with good workability, and has excellent handling characteristics at the connecting portion. .

[0009]

In order to achieve the above object, the present invention is concentrically formed by using an ultraviolet curable resin on the outside of a wire having the same coating material and outer diameter as the optical fiber wire in the optical fiber tape. Provided is a coated single-core optical fiber having an outer diameter of 0.6 mm or more.

[0010]

When the single coated optical fiber of the present invention is connected to the optical fiber tape, it is possible to easily remove only the coating applied to the outside of the strand of 15 cm or more by using a simple tool. That is, it is possible to use a strand having the same outer diameter as the optical fiber strand in the optical fiber tape. Then, the single-core coated optical fibers having the same number of cores as the optical fiber tape are arranged in a straight line, and the outer coating is removed, and the portions which have become the optical fiber strands are arranged in a straight line without any gaps and fixed. Easy to connect with. Therefore, it can be connected to the optical fiber tape at low cost and with good workability. Furthermore, since the outer diameter of the core wire is set to 0.6 mm or more, the handling property at the connecting portion is also good.
Therefore, the cost for constructing the subscriber optical line can be reduced.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. 4A and 4B are views showing the structure of the single-core coated optical fiber of the present invention, FIG. 4A shows the cross-sectional structure, and FIG. 4B shows the appearance when the coating is removed. Reference numeral 19 is a coating that is concentrically applied to the outside of the optical fiber strand using an ultraviolet curable resin. This is the same coating material as the optical fiber strand in the optical fiber tape and a coating 19 in a concentric circle on the outside of the strand with the outer diameter, using a UV curable resin, and a single-core coated light with an outer diameter of 0.6 mm or more. It is a fiber.

When connecting the single-core coated optical fiber to the optical fiber tape, it is possible to easily remove only the coating 19 on the outside of the strand of 15 cm or more by using a simple tool. That is, it is possible to use a strand having the same outer diameter as the optical fiber strand in the optical fiber tape. Then, the single-core coated optical fibers are arranged in a straight line having the same number of cores as the optical fiber tape, and the outer coating is removed to form the optical fiber strand 13
It can be easily connected to the optical fiber tape by arranging and fixing them in a straight line without a gap.

The optical fiber in the coated single-core optical fiber according to the embodiment of the present invention is a single mode optical fiber, and the coating material is an ultraviolet curing resin. In connection, as shown in FIG. 5, the coating 19 on the outside of the single-core coated optical fiber strand is removed by 15 cm or more, and the same number of cores as the optical fiber tape to be connected are arranged in a straight line to form an optical fiber strand. Place 13 in a straight line with no gaps and tape. Then, the coating of the taped portion is removed, and the collective fusion splicing (FIG. 5a) or the multi-core collective optical connector connection (FIG. 5b) is performed. Here, the coating 19 on the outer side of the strand is removed by 15 cm or more because the above-mentioned length is required for arranging the portion 13 that has become the optical fiber strand linearly without gaps and forming a tape and collectively connecting. Is.

Table 1 shows the measurement results when the single-core coated optical fiber of the present invention and the four-core optical fiber tape were connected, in comparison with the results of the conventional mutual connection of the four-core tapes.

[Table 1]

As a result, there is an additional step of removing only the coating on the outside of the strand of 15 cm or more to form an optical fiber tape with the same number of cores, but this shows that the connection time only increases by about 2 minutes. ing. This means that by adding the above function to the single-core coated optical fiber, it is possible to connect the optical fiber tape easily and with good workability. In addition, the optical loss characteristic of the connection portion is the same as the characteristic of the conventional mutual connection of the optical fiber tapes. From the above results, it can be seen that the single-core coated optical fiber having the above function can be easily connected to the optical fiber tape, and the connecting portion has stable characteristics. Although many structures of single-core coated optical fibers have been proposed so far, it has been impossible to easily form a bare fiber in a few minutes with a simple tool.

Furthermore, since the operator handles the connection portion of the coated optical fiber, the handling characteristic of the optical fiber is an important item. As one of the methods for evaluating the handling characteristics of the optical fiber, there is a method shown in FIG. this is,
This is a method in which a coated optical fiber with a weight is dropped, the increase in optical loss at that time is measured, and the handling characteristics are evaluated from the increase in optical loss. The weight used for the measurement is 1 g. This is a measurement method assuming that the coated optical fiber is hooked during handling of the coated optical fiber in the connection portion due to trouble relocation work or the like.

The results measured by this method are shown in FIG. From this, it is understood that when the outer diameter of the coated single-core optical fiber is set to 0.6 mm or more, it has the same handling characteristics as the four-core optical fiber tape. For single-core coated optical fibers with an outer diameter of 0.6 mm or more, change in optical loss during the coated optical fiber manufacturing process and heat cycle test (-30 to 60 ° C)
The change in optical loss due to the measurement was measured. In each case, the change in optical loss was about 0.02 dB / km, indicating stable characteristics. From the above results, the outer diameter of the coated single-core optical fiber was set to 0.
Even if it is 6 mm or more, there is no practical problem.

[0018]

As described above, the single-core coated optical fiber of the present invention has stable optical loss characteristics, and by using a simple tool, only the coating outside the strand of 15 cm or more can be obtained. Since it can be easily removed, that is, it can be made into an optical fiber strand, it has a feature that it can be connected to an optical fiber tape at low cost and with good workability. Since the outer diameter of the core wire is 0.6 mm or more and the handling property at the connecting portion is good, the cost for constructing the subscriber optical line can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a facility configuration of a subscriber system.

FIG. 2 is a diagram showing a structural example of a high-density, multi-core optical fiber cable.

FIG. 3 is a diagram showing a core number conversion code.

FIG. 4 is a diagram showing a single-core coated optical fiber of the present invention.

FIG. 5 is a diagram showing an outline of connection between a single-core coated optical fiber of the present invention and an optical fiber tape.

FIG. 6 is a diagram showing a method for measuring a handling characteristic of a coated optical fiber.

FIG. 7 is a diagram showing measurement results of handling characteristics of a coated optical fiber.

[Explanation of symbols]

 1 Intra-station transmission device 2 Optical fiber cable terminal rack 3 Subscriber transmission device 4 Outdoor transmission device 5 Optical fiber cable 6 Metal cable or coaxial cable 7 4 core optical fiber tape 8 Optical fiber cable jacket 9 Center tension member 10 Slot rod 11 Construction Copper wire for meetings at times 12 Optical fiber 13 Concentric coating of optical fiber 14 Collective coating 15 Multi-core collective optical connector plug 16 Optical fiber tape separating section 17 Single-core optical connector 18 Single-core coated optical fiber 19 Optical fiber element wire Outer concentric coating

Claims (1)

[Claims] 1. An optical fiber element wire having the same coating material and outer diameter as an element fiber used for an optical fiber tape having a structure in which a plurality of optical fiber element wires coated with an ultraviolet curable resin are arranged in a straight line and collectively covered. The single-core coated optical fiber is characterized in that an outer diameter of 0.6 mm or more is further coated with a UV curable resin in a concentric shape with no gaps.