JP2003035851A - Optical fiber ribbon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical fiber ribbon improving a polarization dispersing property and suitable for large-capacity communication including wavelength multiplexing communication. SOLUTION: The optical fiber ribbon is characterized by having a plurality of jacketed optical fibers not in contact with each other and coated in a lump.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber ribbon used mainly for communication. 2. Description of the Related Art As shown in FIG. 3, an optical fiber ribbon used for conventional optical communication applications is an optical fiber core 21.
Are arranged in a state where the optical fiber cores 21 are in contact with each other, and these cores 21 are collectively covered with a coating layer 22 made of an ultraviolet curable resin. In order to manufacture an optical fiber cable using such an optical fiber ribbon 20, a plurality of the above-described optical fiber ribbons 20 are assembled into a cable. Multiple optical fiber ribbons 2
The set of zeros is configured to be dropped into a slot having a groove that is spirally or twisted. On the other hand, in optical communication technology, strict management of dispersion characteristics has been required due to the increase in capacity including wavelength multiplex communication in recent years. For this reason, a situation has arisen in which the polarization dispersion (PMD) characteristics and the like must be managed even in an optical fiber cable. [0004] The polarization dispersion characteristic is strongly affected by the lateral pressure from the outside of the optical fiber. Therefore, in order to improve the polarization dispersion characteristics of the optical fiber ribbon, the polarization dispersion characteristics are improved by twisting the optical fiber ribbon and randomizing the polarization plane. However, in the optical fiber ribbon, as shown in FIG. 3, since a plurality of optical fiber cores are arranged in parallel in a state of contact with each other, the optical fiber cores at both ends and those other than both ends are located at a middle position. The polarization dispersion behavior differs from that of the optical fiber core, and the optical fiber core located in the middle receives side pressure from the cores located on both sides of the core, and the polarization dispersion characteristic tends to deteriorate. (See FIG. 4 described later). In the process of manufacturing an optical fiber cable, if the slot is helical, a twisting stress is applied to the optical fiber from the outside of the optical fiber ribbon. Even if it has deteriorated, by dropping the optical fiber ribbon into the spiral groove, lateral pressure may be applied to the optical fiber ribbon and the polarization dispersion may be reduced. On the other hand, in a slot having a twisted groove, even if the optical fiber ribbon is dropped into the twisted groove, no torsional stress is applied, so that the polarization dispersion is not relaxed. The characteristics will continue as an optical fiber cable. As described above, the deterioration of the polarization dispersion characteristics of the optical fiber ribbons hinders the increase in capacity in wavelength division multiplexing communication, and in particular, the polarization dispersion characteristics of an optical fiber cable using a twisted groove type slot. Improvement is strongly desired. The present invention improves the polarization dispersion characteristic which has been a problem in the conventional optical fiber ribbon, and has good polarization dispersion characteristics even in an optical fiber cable using a twisted groove type slot. An object of the present invention is to provide an optical fiber ribbon which can manufacture a fiber cable. [0008] That is, the present invention is an optical fiber tape, wherein a plurality of optical fiber cores are collectively coated without contacting each other. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an optical fiber ribbon according to the present invention will be described with reference to the drawings. FIG. 1 shows an embodiment of the present invention, in which 10 is an optical fiber ribbon, and the optical fiber ribbon 10 is a plurality of optical fiber ribbons 1 (four in the figure). A plurality of optical fiber core wires 1 arranged in parallel are collectively covered with a coating layer 2 with a predetermined interval between them. The coating layer 2 is made of, for example, an ultraviolet curable resin and is configured to wrap the optical fiber core wire 1 without any gap. By separating the optical fibers 1 and 2 without contacting them,
The side pressure from the adjacent optical fiber core 1 is eliminated, and the deterioration of the polarization dispersion characteristic is improved. FIG. 2 shows a second embodiment of the present invention, in which a coating layer 2 covering an optical fiber 1 is provided with a gap 3 between the coating layer 2 and the optical fiber 1. Thus, by providing a gap between the optical fiber cores 1 and 1, the side pressure from the adjacent optical fiber cores 1 is further reduced, and the polarization dispersion characteristics are further improved. FIG. 4 shows the optical fiber ribbon 10 shown in FIG. 1 manufactured by separating the optical fibers 1 and 1 shown in Table 1, and the polarization dispersion value (p) of the optical fiber ribbon 10 shown in FIG.
s / rkm). As is clear from FIG. 4, by processing the optical fiber core 1 into an optical fiber tape, the polarization dispersion value is slightly higher than the polarization dispersion value at the time of the optical fiber core. The polarization dispersion value is remarkably improved as compared with the optical fiber ribbon in which the optical fiber core is contacted. [Table 1] As shown in FIG. 4, as the spacing between the optical fiber ribbons 1 and 1 is increased up to 20% of the outer diameter of the optical fiber, the polarization dispersion value is improved. No further improvement is seen. Therefore, the distance between the optical fiber cores 1 and 20 is 20% of the outer diameter of the optical fiber core 1.
It is preferable that they are separated from each other. According to the present invention, there is provided an optical fiber ribbon, wherein a plurality of optical fibers are coated at a time without contacting each other.
By providing an interval between the two, the polarization dispersion characteristic can be remarkably improved, and an excellent effect of providing an optical fiber ribbon suitable for large capacity such as wavelength division multiplexing communication can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view showing an embodiment of the optical fiber ribbon of the present invention. FIG. 2 is a sectional view showing a second embodiment of the optical fiber ribbon according to the present invention. FIG. 3 is a cross-sectional view showing a conventional optical fiber ribbon. FIG. 4 is a graph showing a relationship between an interval between optical fiber core wires and a polarization dispersion value in the optical fiber tape core wire. [Description of Signs] 1 Optical fiber core 2 Coating layer 10 Optical fiber tape core

Claims (1)

Claims: 1. An optical fiber ribbon, wherein a plurality of optical fibers are coated collectively without contacting each other.