JP3274582B2 - Optical fiber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber having a novel structure which can be advantageously used for high-density optical communication and the like. More specifically, the present invention provides an optical fiber that can effectively protect an optical fiber core wire and is convenient to handle when manufacturing a multi-core optical fiber core or connecting to another optical fiber core or the like. Regarding the structure of the cord.

[0002]

2. Description of the Related Art With the recent progress of information communication, there is an increasing demand for faster signal transmission. Practical use of optical communication technology is mentioned as a materialization of such a high-speed signal transmission technology. That is, optical signal transmission has advantages in communication technology such as realization of high-speed transmission by the characteristics of light itself, light weight of an optical fiber as a transmission line, and little influence of a magnetic field, an electric field, and the like. I have.

[0003] However, even with such an optical fiber transmission line, a demand for transmission of a larger amount of signal still remains.
In response to this, various devices have been proposed for optical fibers for signal transmission. One developed under such a technical background is a multi-core optical fiber core (batch-coated optical fiber core). In other words, a multi-core optical fiber is usually formed by integrating a plurality of optical fiber single-core fibers, which are optical waveguides, with a common coating layer to form, for example, a tape-shaped optical fiber core. Attention has been paid to realizing high-density signal transmission.

[0004]

However, in the conventional multi-core optical fiber core, a coating layer of an ultraviolet curing resin or the like is provided on the optical fiber to form a single optical fiber, and a plurality of such cores are further provided. Single optical fibers were arranged in parallel and used with a common batch coating layer. In the case of such a multi-core optical fiber, there are the following problems. In other words, when connecting a multi-core optical fiber to another optical fiber, it is difficult to handle it as it is in the form of a single tape such as a tape, and there is a problem of transmission loss due to the connection. And it is necessary to perform connection processing for each single optical fiber.

However, in many cases, the single optical fiber constituting the multi-core optical fiber does not always have the same diameter as the optical fiber single core on the connection side. The dimensions were adjusted by removing the release layer of the dimensions, but at present it is not possible to sufficiently cope with single-core optical fibers because they have grades of various diameters. Also, when manufacturing a multi-core optical fiber by arranging a plurality of single-core optical fibers in parallel and applying a common coating layer, a single-core optical fiber having the same diameter is often used. There was a problem that it was necessary to prepare many kinds and many pieces, and it was costly.

[0006]

As a result of various studies on the above problems, the present inventor has designed in advance the thickness of each coating layer constituting the single-core optical fiber, and removed the outermost coating layer. By exposing the coating layer, which was the conventional inner layer, to form a new outermost layer, the coating of the outermost layer to be further removed is cut in a substantially axial direction or a substantially spiral shape of the optical fiber, whereby The inventors have found that the problem can be solved, and have completed the present invention.

[0007] That is, the present invention is:
In an optical fiber cable with multiple coating layers, a single
Core wire, the cure shrinkage of the outer layer coating is lower than that of the inner layer.
SmallerCoating outer diameter setting is 0.25 ± 0.01mm
Is approximately an integral multiple ofAnd removing the outermost coating layer
As a result, the coating layer,
To provide a new outermost optical fiber core. Ma
Was  The outermost layer to be removed is coated in the
Or a spiral cut into the optical fiber
This feature makes the removal of the coating easy.
I do. Also,  50% or more of the thickness of the outer coating layer to be cut
It also has a feature in that it is cut.

[0008]

The following is a specific description based on the drawings. FIG. 1 is a schematic view showing a cross section of a single-core three-layer coated optical fiber designed in advance to a predetermined coating diameter. In FIG. 1, A is a glass fiber, B is an optical fiber single-core fiber having a coating layer 1 to 4 provided thereon, and the coating layers 1 to 4 are designed to have a predetermined coating diameter in advance.

The present invention is directed to an optical fiber single core B having a plurality of coating layers 1 to 4 designed to have a predetermined diameter and made of an ultraviolet-curable resin, wherein the outermost coating layer, for example, the coating layer 4 By removing the coating layer, the coating layer 3 which was conventionally the inner layer is exposed and becomes a new outermost layer, and it becomes easy to arrange a plurality of coated fibers at a predetermined pitch, thereby facilitating the production of a collectively coated core wire. It is characterized by the following.

More specifically, a single optical fiber B having a plurality of coating layers 1 to 4 designed in advance to a predetermined diameter is converted into a glass fiber A drawn to a constant diameter.
It can be easily manufactured by repeatedly applying and curing the ultraviolet curable resin in a predetermined manner at a constant linear speed and for a constant time so as to have a predetermined coating diameter. Of the coating layers 3 and 4,
The coating layers other than the coating layers 1 and 2 which are in close contact with the glass fiber A, that is, the coating layers 3 and 4 are all removed at the time of processing described later so that the optical fiber single core fiber has a desired diameter. The diameter was easily reduced.

That is, when arranging a plurality of single-core optical fibers B having the coating in parallel to form a collectively coated electric wire, the single-core optical fiber B has a predetermined constant diameter, Coating layers 3 to 4 so that they have the same diameter when connected to a collectively covered electric wire or a single optical fiber.
Either or both may be removed to form a blanket coated optical fiber ribbon or to be connected to another batch coated optical fiber ribbon or a single optical fiber.

The coating material constituting the plurality of coating layers is not particularly limited as long as it is an ultraviolet curable resin, but it is possible to use the same coating material or to use coating materials having different compositions according to purposes. It is good. Usually, a soft layer acting as a cushion, for example, a UV-curable silicone, a UV-curable urethane acrylate, a UV-curable epoxy acrylate, an ester acrylate, or the like is used for the coating layer 1 in contact with the glass fiber A, and the outer layer (the coating layer 2) is used. ), It is desirable to use a hard layer for protecting the glass fiber A, for example, an ordinary ultraviolet curable resin.

Further, in order to facilitate the removal and peeling of the coating layer to be removed or the coating layer immediately before it in the processing described later, a material for imparting lubricity to make the coating layer easily peelable, for example, ultraviolet curing It may be composed of a mold silicon resin, silicon oil or fluorine resin, or may be partially blended. In such a case, it is necessary to select the composition and the amount of the material to provide the lubricating property so that the coating layer to be removed and peeled is not easily detached from the single fiber of the optical fiber so as to be easily peeled. There is.

Further, in the present invention, the set value of the outer diameter of the coating to be removed / stripped is substantially an integral multiple of 0.25 ± 0.01 mm.
It is suitable for connection because it was designed to Furthermore, in the present invention, it is necessary from the viewpoint of removal that the outer layer should have a smaller curing shrinkage than the inner layer in order to remove and peel off the outer layer during subsequent processing.

FIG. 2 is a schematic view showing a case where a cut is provided in the outermost layer of the single-core optical fiber coated with four layers in FIG. In FIG. 2, a notch 5 for facilitating removal and peeling is provided in the outermost layer of the single-core optical fiber coated with four layers in FIG. The cut 5 is desirably formed substantially in the axial direction of the optical fiber or substantially spirally with respect to the optical fiber from the viewpoint of removing and peeling the outer layer. And the cut 5 is 50% or more, preferably 70% of the thickness of the coating outer layer.
It is desirable from the point of removal and peeling that it is above.

[0017]

The present invention is illustrated in more detail by the following examples, which do not limit the scope of the invention. (Embodiment 1) An optical fiber core of the present invention will be described in detail with reference to FIG. Each of the coating layers 1, 2, 3, and 4 having a diameter of 0.18 m around a glass fiber A having a diameter of 125 μm.
m, 0.25 mm, 0.50 mm, and 0.75 mm are concentrically surrounded.

Since the coating layer 1 is in direct contact with the glass fiber A, the modulus of elasticity is 0.1 kg /
mm ² of UV-curable urethane acrylate, and the coating layer 2 is made of UV-curable urethane acrylate having an elasticity of 6 × 10 kg / mm ^2.
X10 kg / mm ² of UV-curable urethane acrylate to which about 1% by weight of silicone oil is added as a release agent. Further, the coating layer 4 has an elastic modulus of 6 × 10 kg / mm ^2.
It is composed of an ultraviolet-curable urethane acrylate of mm ² . However, the curing shrinkage of the coating layer 3 was adjusted to be about 4% while the curing shrinkage of the coating layer 3 was about 6%. Since the coating layer 1 is a cushion layer, it is usually not exposed, and the coating diameter to be exposed is 0.25 mm, 0.5 mm,
Since it is composed of 0.75 mm, it is an integral multiple of 0.25 mm. Further, as shown in Table 1 below, it can be seen that the curing shrinkage of the outermost coating layer 4 is smaller than that of the inner coating layer 3.

[0019]

[Table 1]

Embodiment 2 A method of removing a coating will be described in detail with reference to FIG. FIG. 2 schematically illustrates a state in which a cut 5 is made in the outermost coating 4 of the optical fiber of the present invention. Attempting to remove only the coating layer 4 when the cuts 5 are not made may remove or damage some or all of the other coating layers. The degree of cut of the coating is preferably small (shallow) from the step of cutting, and larger (deep) is preferable from the step of removing. No significant effect was observed when the degree of cut of the coating did not reach 50% of the coating layer, but desirably, when the cut of 70% or more was made, removal of the coating layer was facilitated.

[0021]

As described above, according to the present invention, the thickness of each coating layer constituting the single optical fiber is designed in advance,
By removing the outermost layer and exposing the inner layer to form a new outermost layer, the outermost layer to be further removed is coated in a substantially axial direction or a substantially spiral shape of the optical fiber. By making a cut in the shape, the coating can be easily removed, and a batch-coated optical fiber core wire or a single optical fiber core wire of various diameters can be easily manufactured, and can be combined with another optical fiber core wire having a different diameter. Provided is an optical fiber core structure that is easy to connect and easy to handle.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a cross section of a single-core four-layer coated optical fiber designed in advance to a predetermined coating diameter.

FIG. 2 is a schematic view showing a case where a cut is provided in the outermost layer of the single-core optical fiber coated with four layers in FIG.

[Explanation of symbols]

Reference Signs List A Glass fiber B Single-core optical fiber Coating layer 1-4 Coating layer designed to a predetermined coating diameter in advance on glass fiber strand A 5 Cut

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shigekazu Hayami 1-1-6 Uchisaiwaicho, Chiyoda-ku, Kanagawa Nippon Telegraph and Telephone Corporation (72) Inventor Yu Yu Nozawa 1-16-1 Uchisaiwaicho, Chiyoda-ku, Kanagawa Nippon Telegraph and Telephone Corporation (72) Inventor Hideyuki Iwata 1-1-6 Uchisaiwaicho, Chiyoda-ku, Kanagawa Prefecture Nippon Telegraph and Telephone Corporation (56) References JP-A-2-24610 (JP, A) JP-A-62 JP-A-131212 (JP, A) JP-A-6-43345 (JP, A) JP-A-3-69907 (JP, A) JP-A-3-155510 (JP, A) JP-A-5-45546 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G02B 6/00 G02B 6/10 G02B 6/16-6/22 G02B 6/44

Claims (3)

(57) [Claims] An optical fiber core having a plurality of coating layers designed to have a predetermined diameter and made of an ultraviolet-curable resin, wherein a single core wire has a curing shrinkage rate of a coating of an outer layer and that of an inner layer. The outer diameter of the coating is set to 0.25 ± 0.0
An optical fiber core wire which is approximately an integral multiple of 1 mm and is newly formed as an outermost layer by exposing a coating layer which has been a conventional inner layer by removing the outermost coating layer. 2. The removal of the outermost layer coating to be removed is facilitated by making a cut substantially in the axial direction of the optical fiber or substantially spirally with respect to the optical fiber. The optical fiber core according to claim 1 . 3. The optical fiber core according to claim 2 , wherein 50% or more of the thickness of the outer coating layer to be cut is cut.