JPH06201955A - Optical unit and optical cable - Google Patents

Abstract

PURPOSE:To house optical fibers at a high density by arranging these fibers on a tensile wire having a resin layer having a prescribed Young's modulus formed on its outer periphery and providing this resin layer or resin tape thereon. CONSTITUTION:The optical unit is constituted of the tensile wire 1 on the outer periphery of which the resin coating layer 2 is formed, the optical fibers 3 which are placed longitudinally on this wire or spirally wound thereon and the resin coating body 4 which fix the respective fibers. A glass fiber reinforced plastic or steel wire etc., which have a high mechanical strength and are stable to temp., etc., are used for the tensile wire 1 in such a case. The optical unit 5 is formed by using the resin having <=40kg/mm<2> Young's modulus for the coating layer 2 and the resin coating body 3 and has 35 to 120mum thickness of the thin layer. The resin of the coating layer 2 and the coating body 3 is preferably a polyamide resin or fluororesin and the m.p. of the thermosetting or UV-curing type resin is preferably >=150 deg..

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical unit in which optical fiber strands are housed in high density and an optical cable using the same.

[0002]

2. Description of the Related Art An optical fiber, which is made of glass as a transmission medium, is not affected by electromagnetic induction, has a wide usable band, and has a small fiber outer diameter, so that the transmission amount per unit cross-section area is remarkably increased. It has the feature of being able to However, this optical fiber also needs to be mechanically reinforced, and even if the outer diameter of the glass fiber is as small as 125 μm, the outer diameter of the optical fiber strand is 400 μm because the thermosetting resin is covered thereover. Was there. Further, as a method of assembling these, for example, as shown in FIG. 4, six optical fiber strands 12 are twisted around a tensile strength wire 1 and a coating 4 is provided thereon to provide an outer diameter 1.
It formed an 8 mm optical unit.

[0003]

Not only is it desirable to reduce the cross-sectional area of an optical cable because the cost is reduced, but in the case where there is a limited space for accommodating optical fibers, such as an optical fiber composite overhead wire, that is not the case. The storage density must be increased. Further, the optical fiber composite overhead wire requires a structure capable of withstanding at least 140 ° C. because a large current flows due to a short circuit accident and the temperature rises. Therefore, an object of the present invention is to provide an optical unit and an optical cable using the same that solves the above problems.

[0004]

According to the present invention, an optical fiber wire coated with a thin layer of thermosetting or ultraviolet curable resin is arranged around a tensile strength wire covered with a resin coating layer,
The outer periphery of the optical unit is covered with a resin coating, and the resin of the coating layer and the coating has a Young's modulus of 40.
kg / mm ² or less, and the thin layer has a thickness of 35 μm to
It is an optical unit of 120 μm. Here, it is preferable that the resin of the coating layer and the coating is a polyamide resin or a fluororesin, and the melting point of the thermosetting or ultraviolet curable resin is 150 ° C. or higher.

Further, the present invention is an optical cable in which a plurality of the optical units are gathered around a resin-coated tensile strength wire and are covered with an outer jacket.

The present invention is also an optical cable in which the optical unit is introduced into a groove formed in a spiral shape on the surface of a metal filament, and the opening of the groove is covered with a metal jacket.

[0007]

According to the present invention, since the optical fiber element wire is arranged on the tensile strength wire on the outer periphery of which the resin layer having a predetermined Young's modulus is applied, and the resin layer or the resin tape is provided thereon, The glass fiber is protected from the inside and the outside. Therefore, it is possible to reduce the thickness of the coating of the wire and, even if the outer diameter of the tensile strength wire increases due to the coating, it is possible to arrange as many wires as possible. Can be stored at high density. Further, by applying the above-mentioned resin having heat resistance, the present invention can exert an effect where high temperature characteristics are required such as an optical fiber composite overhead wire.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view showing the configuration of this embodiment,
Reference numeral 1 is a tensile strength wire having a resin coating layer (2) on its outer periphery, 3 is an optical fiber element wire vertically attached or spirally wound thereon,
Reference numeral 4 denotes a resin coating body fixing these, and the optical unit 5 is formed. The tensile strength wire 1 has a large mechanical strength,
Glass fiber reinforced plastic or steel wire, which is stable to temperature, is used.

The optical fiber strand 3 is formed by applying a thin layer of thermosetting resin or ultraviolet curing resin on a glass fiber having an outer diameter of 125 μm. Acrylic resin or silicone resin is suitable for the resin used for coating the strands, but silicone resin is more preferable because it can impart heat resistance of 150 ° C. or higher. The resin coating 4 is extrusion-coated with resin or is wrapped with a resin tape to fix the fiber strand. The resin coating layer 2 or the resin coating 4 is preferably made of a material having a high cushioning property. Further, since it is often used in a high temperature state like a composite overhead wire, a polyamide resin or a fluorine-based resin having a high melting point (tetrafluoroethylene-hexafluoropropene copolymer, tetrafluoroethylene-perfluoro copolymer, A heat resistant resin such as AFLON) is preferable.

With this structure, since the optical fiber strand is surrounded by the soft resin material, the transmission loss does not increase even if the strand coating is a thin layer, and therefore the strand density is increased. You can That is, since the outer diameter of the strand can be changed from the conventional 400 μm to 250 μm, the outer diameter of the optical unit is the same as the conventional 1.8 m.
Twelve can be stored in m (see FIGS. 1 and 4).

As shown in FIG. 5, the increase in transmission loss after forming an optical fiber and an optical unit using the same is affected by the Young's modulus of the resin, and tends to increase when it exceeds 60 kg / mm ² . On the other hand, when the Young's modulus of the resin is within the above range, the thin layer of the thermosetting resin or the ultraviolet curable resin can be further thinned, but 35 μm is a practical limit, and 50 to 100 μm is a preferable thickness.

FIG. 2 shows an optical cable in which six optical units 5 are assembled on a tensile strength wire 6 having the above-mentioned resin applied thereto and a jacket 8 is provided. Further, FIG. 3 shows an optical cable in which the optical unit 5 is housed in a groove of a spacer 9 in which four grooves 10 are spirally provided on the outer circumference of an aluminum wire, and the periphery of the spacer is covered with a metal jacket 11. These cables can store the optical fiber wires in high density, and can be used as an optical fiber composite overhead wire by applying a heat resistant resin. The softer the lower limit, the higher the effect, but 1 kg / mm ² or more is required to maintain the structure. The preferred range is 5 to 40 kg / mm ^2.
Is.

[0013]

As described above, according to the present invention, an optical fiber element wire is arranged on a tensile strength wire having a resin layer having a predetermined Young's modulus applied to the outer periphery thereof, and the resin layer or the resin tape described above is arranged thereon. Is provided, the glass fiber is protected from the inside and the outside. Therefore, it is possible to reduce the thickness of the coating of the wire and, even if the outer diameter of the tensile strength wire is increased due to the coating, it is possible to arrange as many wires as possible. Can be stored at high density. Further, by applying the above-mentioned resin having heat resistance, the present invention can exert an effect where high temperature characteristics are required such as an optical fiber composite overhead wire.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration according to an embodiment of an optical unit.

FIG. 2 is a perspective view showing a configuration according to an example of an optical cable.

FIG. 3 is a perspective view showing a configuration of an optical cable according to another embodiment.

FIG. 4 is a perspective view showing a configuration of a conventional optical unit.

FIG. 5 is a diagram showing measured values of a relationship between Young's modulus of a resin applied to the present invention and increase of transmission loss.

[Explanation of symbols]

 1, 6: tensile strength wire 2: resin coating layer 3, 12: optical fiber element wire 4: coating body 5: optical unit 8, 11: jacket 9: spacer 10: groove

Front page continued (72) Inventor Yuichi Masami 1 Taya-cho, Sakae-ku, Yokohama-shi, Kanagawa Sumitomo Electric Industries, Ltd. Yokohama Works (72) Inventor Takashi Saito 1 Taya-cho, Sakae-ku, Yokohama, Kanagawa Sumitomo Electric Industries Yokohama Works Co., Ltd.

Claims (5)

[Claims] 1. An optical fiber element wire coated with a thin layer of a thermosetting or ultraviolet curable resin is arranged around a tensile strength wire covered with a resin coating layer, and the outer periphery thereof is covered with a resin coating body. In the optical unit, the coating layer and the coating resin have a Young's modulus of 1 kg / mm ^{2 to} 40 kg / m.
m ² , and the thin layer has a thickness of 35 μm to 120 μm. 2. The optical unit according to claim 1, wherein the resin of the coating layer and the coating is a polyamide resin or a fluorine resin. 3. The optical unit according to claim 1, wherein a melting point of the thermosetting or ultraviolet curable resin is 150 ° C. or higher. 4. An optical cable in which the optical units according to claims 1 to 3 are gathered around a tensile strength wire, and the upper part thereof is covered with an outer cover. 5. The optical unit according to claim 1 is introduced into a groove formed in a spiral shape on the surface of the metal filament,
An optical cable characterized in that the opening of the groove is covered with a metal coating.