JPH0669916U - Fiber optic cable - Google Patents

Abstract

(57) [Abstract] [Purpose] Due to the restriction of the cable structure, the actual length of the optical fiber is prevented from being varied and the diameter can be reduced. [Structure] An optical fiber cable has a central body 8 composed of a tension member 5 and a tension member coating 6 at the center thereof. The optical fiber sheet 9 is wound around the outer periphery of the central body 8 to form the cable core 10, and the sheath 7 is further provided on the cable core 10 to form a cable. In the optical fiber sheet 9, the optical fiber tape 1 and the protective strip 2 having a thickness larger than this are alternately attached at equal intervals and parallel to one surface of the base tape 4 on which the adhesive is applied. The optical fiber tape 1 is formed by arranging a plurality of optical fibers in parallel and collectively covering them. When the base tape 4 is wound around the central body 8 with the protective strip 2 on the outside, the sheath 7 contacts only the protective strip 2 and the optical fiber tape 1 is protected.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an optical fiber cable composed of an optical fiber tape, and more particularly to an optical fiber cable having a small variation in the optical fiber length for use in high-speed transmission such as a computer link connecting between computers. is there.

[0002]

[Prior art]

 In recent years, computers have become more sophisticated and the demands on their transmission lines have become stricter. For example, when ordinary electrical signal cables are used for the links that connect computers (hereinafter referred to as computer links), signal delay is a factor that limits the overall speed, and mutual induction of adjacent wiring also poses a noise source. Becomes Therefore, for computer links, optical fiber cables that do not cause signal delay even in high-speed transmission and do not generate adjacent noise are used. Since a multi-fiber cable is generally desired, a spacer type optical fiber cable containing an optical fiber tape is used.

In a conventional spacer type optical fiber cable, as shown in FIG. 3, an optical fiber tape 12 formed by arranging a plurality of optical fibers 11 in a row and collectively covering them is provided as a spiral strip on the outer periphery of a spacer 13. It is accommodated and twisted in the slot 14 of the. As shown in the figure, the optical fiber tapes 12 may be stacked and housed in order to increase the multiplicity.

[0004]

[Problems to be solved by the device]

 However, when the above-mentioned conventional spacer type optical fiber cable is used for high speed transmission such as computer link, the actual length of each optical fiber in the cable varies, so that the difference in the arrival time of the optical signal between the arithmetic elements is different. There was a problem of getting out of sync. The reason why the actual length of each optical fiber in the cable varies is as follows.

(1) Since the structure is such that the optical fiber tape is stored in the slot, the accuracy of the slot, the fluctuation of the back tension when the optical fiber tape is stored in the slot, and the fluctuation of the optical fiber tape in the slot due to the vibration of the cable There are many factors causing variations in actual length, such as movement.

(2) As a matter of course, when the optical fiber tapes are stacked and housed in one slot in the radial direction, the twisting is different due to the difference in the layer core diameter, and the actual length varies. To avoid this, it is uneconomical to store only one optical fiber tape in one slot.

(3) Further, in manufacturing the slot, variations in its shape and dimensional variations in the longitudinal direction cannot be avoided. For this reason, the size of the cable becomes large due to the allowance of the size of the slot, making it difficult to reduce the diameter of the cable.

For this reason, in the conventional spacer type optical fiber cable, variations in the actual length of each optical fiber are inevitable in cable manufacturing. Therefore, when used in a computer link or the like, the optical path length during installation is reduced. I was forced to do the complicated work of matching.

The object of the present invention is not to store an optical fiber tape in a slot to form a cable, but to attach the optical fiber tape to a sheet and roll it to form a cable. An object of the present invention is to provide an optical fiber cable that solves the drawbacks of the technology, has a small variation in the actual length of a multi-core optical fiber, and can be made thin.

[0010]

[Means for Solving the Problems]

 The optical fiber cable of the present invention is one in which a single optical fiber sheet in which a plurality of optical fibers are arranged in parallel and covered is wound around a central body and a sheath is provided on the outside. The optical fiber sheet may consist of a single optical fiber tape that is formed by coating a plurality of optical fibers together, and may be wound directly on the central body, or may be formed by coating a plurality of optical fibers together. The optical fiber tapes may be arranged in parallel on the base tape and attached to form a sheet, and the optical fiber tapes may be wound around the central body through the sheet. In this case, in order to protect the optical fiber from contact with the central body or sheath, a part of the optical fiber sheet is raised more than the optical fiber portion, and a protective strip is provided to cut off the contact with the central body or sheath. It is preferable.

In order to minimize the variation in the actual length of the optical fiber, it is preferable that the optical fiber sheet has only one winding and its edges do not overlap. However, as long as it is allowed, the continuous sheet may have multiple windings, or the cut sheet may have multiple layers. When an optical fiber tape is attached to form an optical fiber sheet, the optical fiber tape can be attached to both sides of the base tape, but it is desirable to attach the optical fiber tape to only one side.

In addition, the optical fiber cable of the present invention is configured by arranging a plurality of optical fiber tapes in which a plurality of optical fibers are arranged in parallel and collectively covered. An optical fiber sheet is formed by alternately sticking the above-mentioned optical fiber tape and protective strips thicker than this optical tape on one surface of one base tape at equal intervals and in parallel. A base tape with the above-mentioned optical fiber tape and a protective strip attached, with one surface facing outward and wrapped around the central body to form a cable core, and a sheath on the cable core that contacts only the protective strip. Is. The protective strip may have any cross-sectional shape as long as it is thicker than the optical fiber tape.

[0013]

[Action]

 If an optical fiber sheet with multiple optical fibers arranged in parallel and coated is simply wrapped around the center body, the effect of slot and back tension fluctuation when the slot is housed are different from when the optical fiber tape is housed in the slot. There is no such factor as the actual length variation.

In addition, when a protective strip thicker than the optical fiber tape is attached to the base tape, the optical fiber tape is protected without coming into contact with the sheath, and therefore loss due to microbending or the like due to the contact of the sheath. Is avoided.

In particular, when only one optical fiber sheet having one layer of optical fiber is wound around the central body, variations in actual length due to differences in layer core diameter are eliminated.

[0016]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a sectional view of an optical fiber cable according to the present embodiment, and FIG. 2 is a developed view of an optical fiber sheet showing a main part thereof. The optical fiber cable shown in FIG. 1 has a central body 8 composed of a tension member 5 and a tension member coating 6 at the center. For example, a tensile strength member such as FRP, steel wire, and steel stranded wire is coated with PE, PVC, or the like. The optical fiber sheet 9 is directly wound around the outer periphery of the central body 8 to form the cable core 10. The winding of the optical fiber sheet 9 is performed so that the axial direction of the optical fiber tape 1 and the axial direction of the central body 8 which constitute the optical fiber sheet 9 are parallel to each other, and the edges do not overlap with each other only once. To do. The cable core 10 is further provided with a sheath 7 to be cabled. The sheath may have one layer or two or more layers. The optical fiber sheet 9 wound around the central body 8 has the following structure.

As shown in FIG. 2, the optical fiber sheet 9 includes an optical fiber tape 1 and a protection strip 2 thicker than the optical fiber tape 1 alternately on one surface of the base tape 4. It is configured by being attached in parallel at intervals. The sticking is performed with the adhesive 3, but an adhesive may be used. The optical fiber tape 1 is formed by arranging a plurality of optical fibers in parallel and collectively covering them, as in the conventional case. Usually, a curable resin is used as the collective coating material. The protection strip 2 disposed between the optical fiber tapes has a circular cross section, whereby the contact with the sheath 7 is cut off to eliminate microbend loss, and the optical fiber tape 1 is effectively prevented from being crushed by the cable. Protect.

As shown in FIG. 1, the optical fiber sheet 9 thus configured has a central body with one surface of the base tape 4 to which the optical fiber tape 1 and the protective strip 2 thicker than this are adhered as an outer side. Wrapped around 8. Therefore, the sheath 7, which is further provided on the outside as a jacket, does not contact the optical fiber tape 1 but contacts only the protective strip 2.

As described above, according to the optical fiber cable of the above-described embodiment, the optical fiber sheet formed by adhering a plurality of optical fiber tapes to the base tape is wound around the central body without using the slot to form a cable. Therefore, it is possible to reduce the variation in the actual length, which is unavoidable in the cable manufacturing such as the conventional spacer type optical fiber cable. In addition, since there is no room for optical fiber tape movement due to cable vibration even after manufacturing, variations in actual length can be greatly reduced, and as a result, adjustment of the optical path length during cable laying becomes easier and workability improves. .

Next, the above embodiment will be specifically described. Since it is desirable that the optical fiber cable for the computer link has a large number of fibers, a multi-fiber optical fiber tape of 8 to 12 fibers is used. In the case of a 12-core tape, 12 cores of optical fiber coated with a UV-curable resin of φ0.25 mm are arranged in parallel in parallel with each other, and this is coated all together with the UV-curable resin to form a tape core. The size is about 0.3 mm × 3.5 mm.

Twelve optical fiber tapes and twelve φ1 mm polyethylene strings were alternately attached to a polyester tape having a width of 54 mm and an adhesive on one side. The optical fiber sheet in which these were attached and integrated was wrapped around a central body having an outer diameter of 18 mm at a pitch of 500 m so that the edges would not overlap only once, and a sheath was further applied to form a cable. The finished outer diameter was 23 mm. In addition, in the above specific example, the polyester tape and the optical fiber tape are bonded together by using an adhesive, but an adhesive may be used as described above.

When the completed optical fiber cable was examined, it was thinner than the conventional concentric unit type optical fiber cable, and there was little variation in the actual length of each optical fiber in the cable. When this was used for a computer link, there was no difference in the arrival time of the optical signal without adjusting the optical path length, and it was possible to synchronize the arithmetic elements.

[0023]

[Effect of device]

 (1) According to the optical fiber cable of claim 1, the optical fiber sheet in which a plurality of optical fibers are arranged in parallel is wound around the central body to form a cable, so that the optical fiber is stored in the slot. As a result, the back tension of the optical fiber can be stabilized and made uniform, and there are no factors that cause variations in the actual length in subsequent steps, so variations in the actual length of the optical fiber in the cable can be reduced. In addition, since the slot, which requires a large dimensional tolerance, is not used, a small-diameter multi-fiber optical cable can be obtained.

(2) According to the optical fiber cable of the second aspect, in addition to the above effect, the optical fiber tape is protected from the sheath by a protective strip that is thicker than the optical fiber tape. Can be good.

[Brief description of drawings]

FIG. 1 is a sectional view of an optical fiber cable according to an embodiment of the present invention.

FIG. 2 is a sectional view of an optical fiber sheet according to this embodiment.

FIG. 3 is a cross-sectional view showing a conventional spacer type optical fiber cable.

[Explanation of symbols]

 1 Optical Fiber Tape 2 Protective Stripe 3 Adhesive 4 Base Tape 5 Tension Member 6 Tension Member Cover 7 Sheath 8 Center Body 9 Optical Fiber Sheet 10 Cable Core

Claims (2)

[Scope of utility model registration request] 1. An optical fiber cable characterized in that an optical fiber sheet having a plurality of optical fibers arranged in parallel and coated is wound around a central body and a sheath is provided on the outside. 2. An optical fiber cable comprising an optical fiber tape in which a plurality of optical fibers are arranged in parallel and collectively covered, wherein the optical fiber tape and a protective strip having a thickness thicker than the optical fiber tape are base tapes. To form an optical fiber sheet by alternately arranging parallel arrangement on one surface, and winding the optical fiber sheet on the central body with one surface of the base tape having the optical fiber tape and the protective strip attached to the outside. Furthermore, an optical fiber cable characterized by being provided with a sheath that contacts only the above-mentioned protective strip.