JP-7856928-B2 - Fiber optic cable

JP7856928B2JP 7856928 B2JP7856928 B2JP 7856928B2JP-7856928-B2

Inventors

櫻井信
小林駿
菊池雅
松尾崇司
前原泰弘
山田裕介
宝満貞治

Assignees

ＮＴＴ株式会社

Dates

Publication Date: 20260512
Application Date: 20221219

Claims (6)

Optical fiber core and The optical fiber core is surrounded and housed on the inner surface, and the inner surface has a circular cross-sectional shape. It includes four or more tensile strength members embedded in the outer sheath so as to extend along the optical fiber core, Of the four or more tensile strength members mentioned above, four are laid at the vertices of a rectangle centered on the cross-sectional center of the inner surface. An optical fiber cable in which, of the four tensile strength members, the planes that are in contact with the outside of at least one pair of adjacent tensile strength members are arranged to be in contact with the inner surface of the outer sheath.
Optical fiber core and A sheet surrounding the optical fiber core, The optical fiber core is housed by surrounding it on the inner surface via the aforementioned sheet, and the inner surface has a circular cross-sectional shape. It includes four or more tensile strength members embedded in the outer sheath so as to extend along the optical fiber core, Of the four or more tensile strength members mentioned above, four are laid at the vertices of a rectangle centered on the cross-sectional center of the inner surface. An optical fiber cable in which, of the four tensile strength members, the planes that are in contact with the outside of at least one pair of adjacent tensile strength members are arranged to pass through a range from the inner surface of the outer sheath to the inner surface of the sheet.
Optical fiber core and The optical fiber core is surrounded and housed on the inner surface, and the inner surface has a circular cross-sectional shape. It includes four or more tensile strength members embedded in the outer sheath so as to extend along the optical fiber core, Of the four or more tensile strength members mentioned above, four are laid at the vertices of a rectangle centered on the cross-sectional center of the inner surface. An optical fiber cable in which, of the four tensile strength members, the planes that are in contact with the outside of at least one pair of adjacent tensile strength members are parallel to the axis that minimizes the second moment of the cross-section in a cross-section perpendicular to the longitudinal direction of the outer sheath, and are arranged to be in contact with the inner surface of the outer sheath.
The optical fiber cable according to claim 1 or 2, wherein the outer surface of the outer sheath is processed to indicate a position of a plane that is in contact with the inner surface of the outer sheath.
The optical fiber cable according to any one of claims 1 to 3, wherein the tensile strength member has a different color from the outer sheath.
Optical fiber core and An outer sheath that surrounds and houses the optical fiber core on its inner surface, It includes a plurality of tensile strength members embedded in the outer sheath so as to extend along the optical fiber core, Of the plurality of tensile strength members, the planes that are in contact with the outside of at least one pair of adjacent tensile strength members are arranged to be in contact with the inner surface of the outer covering. An optical fiber cable in which the outer surface of the outer sheath has a circular cross-section, and the inner surface has an extremely thin wall thickness at the point where it contacts the plane.

Description

This disclosure relates to optical fiber cables. Optical fiber cables are widely used in the construction of optical communication networks. Patent Document 1 discloses an optical fiber cable in which optical fiber cores are bundled at high density. The outer sheath of the optical fiber cable is provided with a tensile strength member to prevent damage and suppress the increase in transmission loss. In addition, as shown in Patent Document 2, multiple tensile strength members may be used. When removing an optical fiber core housed in an optical fiber cable, it is necessary to remove the outer sheath to expose the optical fiber core. This removal of the outer sheath must be carried out in a manner that does not damage the optical fiber. To remove the outer sheath and extract the optical fiber core, it is necessary to continuously cut the outer sheath along its longitudinal direction. To facilitate this process, the outer sheath has sometimes been provided with a tearing string (see Patent Document 1). Patent No. 4774337Patent No. 6182091 This is a cross-sectional view showing an optical fiber cable according to the first embodiment.This is a cross-sectional view of the optical fiber cable in the first embodiment when the outer sheath is being trimmed.Figure 2 shows a cross-sectional view after further trimming of the outer sheath of the optical fiber cable and removing two adjacent tensile strength members.This is a cross-sectional overhead view showing a modified example of the optical fiber cable according to the first embodiment.This is a cross-sectional view showing an optical fiber cable according to a second embodiment.This is a partially enlarged cross-sectional view of the optical fiber cable according to the second embodiment.This is a cross-sectional view showing an optical fiber cable according to a third embodiment.This is a cross-sectional view showing a modified example of the optical fiber cable according to the third embodiment. The optical fiber cable of this embodiment will be described below, in order from the first embodiment to the fourth embodiment, with reference to the drawings. (First Embodiment) Figure 1 is a cross-sectional view showing an optical fiber cable 10 according to a first embodiment. The optical fiber cable 10 according to the first embodiment includes an optical fiber core 12, an outer sheath 11 that surrounds the optical fiber core 12 and houses the optical fiber core 12 in a space 14 formed by its inner surface 11a, and a plurality of tensile strength members 13 embedded in the outer sheath 11 so as to extend along the optical fiber core 12. The optical fiber core 12 is composed of one or more optical fiber cores 12. The optical fiber core 12 may also be formed by bundling together multiple optical fiber tapes, each tape-shaped in which multiple optical fiber cores 12 are arranged. For example, an optical fiber tape composed of four optical fiber cores 12 may be used, and six of these optical fiber tapes may be bundled together to form the optical fiber core 12. The outer covering 11 is a tubular member having a generally cylindrical shape with predetermined inner and outer diameters for its inner surface 11a and outer surface 11b. The outer covering 11 may be made of a polyolefin synthetic resin, such as polyethylene (PE). The tensile strength members 13 may be positioned in a substantially rotationally symmetrical manner with respect to the axis of the outer sheath 11, which has a substantially cylindrical shape. The tensile strength members 13 may consist of, for example, four tensile strength members 13. The tensile strength members 13 may extend in the longitudinal direction of the outer sheath 11 along the optical fiber core 12 and may have a substantially cylindrical shape. The tensile strength members 13 may be made of fiber-reinforced plastic (FRP) made of aramid fibers or glass fibers, or they may be made of steel wire. In the optical fiber cable 10 of the first embodiment, the plurality of tensile strength members 13 include two adjacent tensile strength members 13 interposed between them such that the plane 21 in contact with the two tensile strength members 13 facing the optical fiber core 12 is in contact with the inner surface 11a of the outer sheath 11. The outer surface 11b of the outer sheath 11 of the optical fiber cable 10 may be processed with protrusions or markings to indicate the position of such plane 21. The process of extracting the optical fiber core 12 from the optical fiber cable 10 of the first embodiment will be explained using Figures 2 and 3. Figure 2 is a cross-sectional view when the outer sheath 11 of the optical fiber cable 10 of the first embodiment is being shaved. As shown in Figure 2, the outer sheath 11 of the optical fiber cable 10 is shaved from the outer surface 11b with a cutting tool toward the plane 21 that is in contact with the two adjacent tensile strength members 13 facing the optical fiber core 12. The position of