JPS59214803A - Optical fiber cable - Google Patents

Abstract

PURPOSE:To improve the efficiency of optical fiber core selection and to reduce the disorder of an optical fiber core array at a connection part by providing a partial set of optical fiber cores which have close transmission characteristics, and discriminating it. CONSTITUTION:A cable consists of parallel optical fiber cores 1 which are not selected according to whether their characteristics are superior or inferior, good optical fiber cores 2 which have superior characterstics higher than a specific standard, a press-winding tape 3, a tensile strength body layer 4, and an LAP sheath 5. The optical fiber cores are classified into the cores 1 and 2 by measuring their transmission characteristics previously. When the optical fiber cores are bundled into the cable, the good optical fiber cores 2 are separated by the press-winding tape 3 and discriminated from the parallel optical fiber cores 1. The numbers of the optical fiber cores 1 and 2 are determined according to the demand of, specially, a cable with superior characteristics. The parallel fiber cores 1 and good fiber cores 2 are connected together separately. Namely, the optical fiber cores having superior characteristics are connected together preferentially.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention utilizes the property that optical fibers have variations in characteristics such as loss and bandwidth to generate optical fibers with excellent characteristics, such as optical loss being smaller than the overall loss average value. The present invention relates to a communication optical fiber cable having a subset of fiber cores.

The characteristics of optical fibers, such as loss and bandwidth, vary and exhibit statistical properties. On the other hand, in a conventional optical fiber cable structure, a plurality of optical fiber cores are simply assembled regardless of their characteristics. Therefore, when connecting multiple cables to configure a long transmission line, if you connect them in the order of the core numbers determined by the cable structure according to the general construction method, the cores will be selected at random from the viewpoint of characteristics, and the overall The optical line characteristics of the transmission line have a limit determined by the statistical properties of the optical fiber characteristics.

In addition, in order to create a transmission path with more desirable characteristics, we actively utilize the statistical properties of optical fibers to measure the characteristics of optical fiber cores and to connect fibers with excellent characteristics or There is a method of selective connection that connects inferior conductors to each other.Figure 1 (a) and (b) are one method of selective connection, and the ← mark means that the wires are connected. Measure all the optical fibers in the cable, number them in order of their characteristics, and then connect the fibers with better characteristics to each other or the fibers with better and worse characteristics to each other in numerical order. The former is called a forward order connection (FIG. 1(a)), and the latter is called a reverse order connection [FIG. 1(b)].

Figures 2 (a) and (b) are conceptual diagrams of another method of selective connection. In the characteristic distribution, the optical 7A/IPA core line belongs to an area whose characteristics are better than a predetermined standard, and the optical line belongs to an area whose characteristics are inferior. The optical fibers are divided into optical fibers, and the optical fibers belonging to the region with excellent characteristics are divided into the optical fibers belonging to the region with excellent characteristics, and the optical fibers belonging to the region with inferior characteristics are divided into the optical fibers (Fig. 2 (a)-), or the optical fibers belonging to the region with excellent characteristics are separated. This is a method of randomly combining and connecting optical fibers belonging to the area and optical fibers belonging to the inferior area [FIG. 2(b)]. The effect of using this type of connection method is that by connecting optical fibers with excellent characteristics, it is possible to create an optical line with lines with particularly excellent characteristics. By connecting a fiber core wire with an inferior optical fiber core wire, an optical line having lines with uniform characteristics with little variation can be realized.

Figure 8 is an example of calculation of the effect when performing a positive order connection as a selective connection.It shows the probability that the allowable loss is satisfied in the total loss distribution when 14 optical fiber cables are connected, and the positive order (
This shows the relationship between the number of times the connection is repeated.

In Figure 8, the allowable loss of the optical fiber cable is 22
dB, and the dotted line in the figure shows the value when no forward order connection is made. In the example of FIG. 8, by performing the normal order connection once, there is an effect of increasing the probability that the allowable loss is satisfied in the total loss distribution from 2.6 inches in the case where the normal order connection is not made to 8.8 days. In this way, selective connection methods such as forward order connection are effective methods.

Now, when applying selective splicing to the conventional optical fiber cable structure, it was necessary to connect and measure the characteristics of all the five optical fibers in the optical fiber cable on site, which had the disadvantage of being inefficient. . In addition, in selective splicing, the optical fibers to be connected are determined based on their characteristics, so the arrangement of the optical fibers at the splicing part is significantly different compared to the case where the optical fibers are connected in the order of the fiber numbers determined by the table structure using the general construction method. There were disadvantages such as confusion, complicated connections, and poor workability.

In order to solve these drawbacks, the present invention actively utilizes the variations in optical fiber characteristics and uses a subset of optical fiber cores with excellent characteristics such as low optical loss to form an optical fiber cable. The present invention will be explained in detail with reference to the drawings below.0 Figure 4 is a book containing a subset of optical fiber cables with excellent characteristics in optical fiber cables. First invention
This is an example of illustrating a cross section of the cable. In Fig. 4, 1 is an average optical fiber that has not been selected based on its characteristics, 2 is a good optical fiber that has excellent characteristics that exceed a predetermined standard, 8 is a rolled tape, and 4 is a tensile strength. Body layer, 5
The transmission characteristics of the 0-optical fibers, which are LAP jackets, are measured in advance, and when the 0-optical fibers are classified into 1 and 2 to be collected and made into a cable, the good optical fibers 2 are wrapped with a push-wrap tape. The number of the zero optical fiber cores 1 and 2, which are separated by 8 so as to be clearly distinguishable from the normal optical fiber core 1, is determined depending on the demand for a line with particularly excellent characteristics.

Since the optical fiber cable structure according to the present invention shown in FIG. When performing a method of splicing by specifically selecting optical fibers that are in the cable, it is possible to save the effort of measuring the characteristics of all the optical fibers in the cable at the connection site.In other words, the characteristics must exceed the specified standards. It is sufficient to use only good optical fiber cores 2.In addition, the optical fiber cores at the joints can be improved by selecting and splicing optical fiber cores with excellent characteristics, which has occurred in conventional optical fiber cable structures. Disturbances in line arrangement can be reduced.

FIG. 5 shows an example of connection when using the optical fiber cable of the first embodiment of the present invention shown in FIG. When connecting optical fiber cables according to the present invention, priority is given to optical fiber cores with excellent characteristics, that is, between the average optical fiber cores l and the good optical fiber cores z. Connection 0 Since such a connection method is performed, the effect is that a line with particularly excellent characteristics can be realized, although the number of lines is small, by using an optical line constructed by connecting only good optical fiber cores 2. In other words, the optical line with excellent characteristics can be realized. By focusing on loss, it is possible to realize the low-loss line required for lines for subscribers far from the telephone office, and apply it to expanding the subscriber coverage area.Also, if we focus on band as a characteristic, It is possible to realize a broadband line necessary for image communication, etc., and it can be applied to the configuration of an economical wideband/non-broadband mixed line when there is little demand for broadband lines.

FIG. 6 shows a second embodiment of the invention and shows a cross section. 6
7 is a standard optical unit consisting of optical fiber cores that are not particularly selected based on their characteristics; The Yoshiko unit 8, which is selected and configured, is a tension member.

In the embodiment of the present invention shown in FIG. 6, there are five Namiko Units Toro and one Ryoko Unit 7, but the Hikari Unit 6.
The allocation ratio of 7 is determined depending on the demand for lines with particularly excellent characteristics.

Since the optical fiber structure according to the present invention shown in FIG. 6 has such a structure, its effect is that the optical unit 7
The same effect as the optical fiber cable structure shown in Fig. 4 can be obtained by using the optical fiber cable belonging to the optical fiber cable structure shown in Fig. 4 in the same manner as the optical fiber cable which has excellent characteristics in the optical fiber cable structure shown in Fig. I can do it.

FIG. 7 shows an eighth embodiment of the present invention, and shows a cross section. The optical fiber cable structure shown in Fig. 7 is a numbered optical fiber core with a number mark attached so that the optical fiber cores with excellent characteristics can be identified in the order of their characteristics. 11 also includes a subset distinguished by the rolled tape 8? 0 FIG. 8(,) shows a fourth embodiment of the present invention and shows a cross section, FIG. 8(b) shows a cross section of the good optical fiber unit shown in FIG. 8(a), and 9 indicates a component. The knit core member 10 is a unit roll. The structure of the optical fiber cable shown in Figure 8 (,) is numbered so that the optical fiber cores with excellent characteristics can be identified in the order of their characteristics as shown in Figure 8 (b). It has a numbered good optical fiber unit 12 in which numbered optical fiber core wires 11 with marks indicating are arranged in numerical order.

Since the optical fiber cable structure of FIGS. 7 and 8 according to the present invention has such a structure, the effect is that optical fibers with excellent characteristics can be used to realize lines with particularly excellent characteristics. When using the method of selecting and connecting fibers, there is no need to measure the characteristics of the optical fiber cores at the splicing site.The optical fiber cores are arranged according to their characteristics, so the optical fiber cores at the splicing area are This has the advantage that the line arrangement will not be disturbed.

As explained above, the optical fiber cable structure according to the present invention has a subset consisting of good optical fiber core wires with excellent characteristics exceeding a predetermined standard, or has a line with particularly excellent characteristics. When selecting and connecting optical fiber cores with excellent characteristics, it is sufficient to use optical fiber cores belonging to a subset consisting of good optical fiber cores; This has the advantage of making the selection more efficient and reducing the disturbance of the optical fiber arrangement at the connection part.

Furthermore, when connecting high-quality optical fiber cores and average optical fiber cores, there are similar advantages in streamlining fiber selection and reducing disturbances in the optical fiber core arrangement at the splicing section, resulting in characteristics with less variation. It can also be applied to optical line configurations for relay systems that require uniform lines.

[Brief explanation of drawings]

Figure 1 (a), (b) and Figure 2 (a),
(b) is a conceptual diagram of selective connection in which optical fiber cores are selected and connected according to their characteristics, Figure 8 is a diagram showing an example of calculating the effect of selective connection using forward order connection as an example, and Figure 4 is a diagram of the present invention. FIG. 5 is a sectional view of a first embodiment of the optical fiber cable structure according to the invention, FIG. 5 is a perspective view of an embodiment for connecting the cable of the invention shown in FIG. Cross-sectional view of the embodiment 1. FIG. 7 is a sectional view of the eighth embodiment of the present invention, FIG.
FIG. 8(b) is a detailed sectional view of the optical fiber unit shown in FIG. 8(a). 1... Average optical fiber coated wire, 2... Good optical fiber coated wire,
8... Press-wound tape, 4 - Tensile strength layer, 5... LA
P outer covering, 6...Noriko unit, 7...Good light unit, 8
...Tension member, 9 ・Unit center member, l
0...Unit push winding, 11...Numbered optical fiber core wire, 12...Numbered Ryoko unit. Patent applicant Nippon Telegraph and Telephone Public Corporation Figure 1 (a) (b) Figure 2 (a) (b) Figure 3 Figure 4 Figure 7 (a)

Claims (1)

[Scope of Claims] 1. In an optical fiber cable having a structure in which a plurality of optical fiber cores having dispersion in optical transmission characteristics are bundled, a subset of fiber cores having similar transmission characteristics is formed and the subset can be identified. An optical fiber cable characterized by: (a) The optical fiber cable according to claim 1, wherein the optical fiber cores in the subset can be identified in the order of their characteristics.