JPH02208241A - Production resin-coated optical fiber - Google Patents

Abstract

PURPOSE:To make the surface of resin-coated optical fiber uniform and not to let elongated strain readily occur by forming unevenness on the surface of outer peripheral coated layer of resin-coated optical fiber prepared by coating optical fiber with a resin. CONSTITUTION:Glass 1 is coated with a coating resin such as ultraviolet-curing resin of urethane acrylate base to give optical fibers 2. The plural optical fibers (e.g. four optical fibers in one row) are commonly passed through a resin coating device of a die 40 for tape core wire equipped with unevenness on the inner surface of the die. Then the coating layer 3 having formed unevenness on the outer periphery of the optical fiber 2 is treated to produce resin-coated optical fiber of tape core wire 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a resin-coated optical fiber, and more particularly, to a method for manufacturing a resin-coated optical fiber in which a coating layer having excellent bending properties is formed.

[Conventional technology]

FIG. 3 shows the cross-sectional structure of a ribbon spacer cable using optical fibers. 31 is a rod-shaped grooved spacer provided with a groove 32 on the outer periphery, and usually at least one groove 32 is provided with a groove 32.
A structure (hereinafter referred to as a spacer structure) in which a laminate of resin-coated optical fibers (hereinafter referred to as optical fibers) arranged in rows and laminated with tape-shaped optical fiber cores that are collectively coated in common is housed.

The optical fiber unit 33 of ) has excellent characteristics such as high density and easy connection because it can be made for each optical fiber.

In Figure 3, 34 is the presser tape, 35 is the cable sheath,
36 is a tensile strength member.

When an optical fiber unit with a spacer structure is bent, stretching strain occurs in the optical fiber located on the outside of the bend.
Compressive strain occurs in the optical fiber located in the bent inner portion.

Since elongation strain promotes the elongation of cracks on the optical fiber surface,
Continuing to apply large strain for a long period of time is not desirable from the viewpoint of long-term reliability. Furthermore, since the spacer-structured optical fiber unit has a structure in which the optical fiber core wire laminate is wound, lateral pressure is applied to the optical fiber when stretching strain occurs. Therefore, it is necessary to suppress the elongation strain to a small level in view of the increase in transmission loss due to lateral pressure. In order to suppress bending strain, there is an example in which the outermost coating layer of an optical fiber is made of a material having a coefficient of static friction of 0.9 or less, as disclosed in Japanese Patent Application Laid-Open No. 62-89915. Further, as a method for forming the outermost coating layer using a material having a static friction coefficient of 0.9 or less, for example, Japanese Patent Publication No. 42247/1984 (Q) discloses a method of applying powder around an optical fiber.

[Problem to be solved by the invention]

The conventionally proposed method of coating an optical fiber with fine powder of a material whose coefficient of static friction is below a certain value to form an outermost coating layer increases the number of manufacturing steps for the optical fiber, reduces productivity, and
There is a problem that not only does the manufacturing cost become high, but there are also restrictions on handling in order to prevent the applied fine powder from falling off or being damaged in the next process.

Further, it is not easy to uniformly apply fine powder to the surface of the optical fiber coating material, and there is also a problem in terms of working environment conditions in which dust is likely to be generated.

Furthermore, the current situation is that there is no suitable material that has sufficiently low friction without applying any treatment to the surface of the coating material.

The present invention solves the conventional problems and provides a resin-coated optical fiber that makes the surface of the coated optical fiber uniform and easily creates a structure that does not cause elongation distortion without applying fine powder or the like to the coated surface of the optical fiber. The purpose of this invention is to provide a method for manufacturing.

[Failure to solve the problem]

In order to achieve the above object, the present invention provides a method for manufacturing a resin-coated optical fiber by coating an optical fiber with a resin.
The step of coating the optical fiber with resin is characterized in that it includes the step of forming irregularities on the surface of the outer peripheral coating layer of the resin-coated optical fiber.

Further, the step of forming irregularities on the surface of the outer circumferential coating layer of the resin-coated optical fiber is effective by applying a step of inserting the resin-coated optical fiber through a die of a resin coating device having irregularities on the inner surface of the die.

Further, as the resin-coated optical fiber, it is effective to use a tape core in which a plurality of optical fibers are coated with a common coating.

[For production]

The method for manufacturing a resin-coated optical fiber of the present invention is such that when coating a bare optical fiber or a resin-coated optical fiber with a coating resin, a resin coating device having an uneven die inner surface is used. , since the surface of the outer coating layer of a resin-coated optical fiber is uneven, the number of manufacturing steps required for surface treatment of the outer coating layer using other materials, such as a method of applying fine powder, is increased; There are no problems such as decreased productivity or increased manufacturing prices, and there are no restrictions on handling. Furthermore, the surface of the outer peripheral coating layer can be uniformly made to have low friction, and there is no adverse effect of dust generation on the working environment conditions. Examples will be described below based on the drawings.

〔Example〕

FIGS. 1a and 1b are cross-sectional structural views of an embodiment of a coated optical fiber manufactured by the manufacturing method of the present invention. FIG. 1a shows an example of a tape core 4 in which a plurality of optical fibers 2 coated on a glass 1 are arranged in a row (four in this example), and a coated layer 3 is commonly coated. It has a structure in which unevenness is formed on the outer periphery. FIG. 1 shows an example of an optical fiber wire 5 in which a coating layer 3 having irregularities formed on the outer periphery is applied to a single glass 1.

FIGS. 2a and 2b are diagrams showing the structure of an embodiment of an optical fiber coating quis applied to the manufacturing method of the present invention, and FIG. 2a is a tape for manufacturing the ribbon core 4 illustrated in FIG. 1a. As an example of the core wire die 40, FIG. 2 is an example of the optical fiber wire die 50 for manufacturing the optical fiber wire 5 illustrated in FIG. 1.

Below, examples of tape core wires, optical fiber core wires, and optical fiber strands that were experimentally manufactured by the manufacturing method of the present invention as shown in FIGS. 1A and 1S will be described.

Example 1: A urethane acrylate-based ultraviolet curable resin was coated on the outer periphery of four coated optical fibers using a tape core die having the structure illustrated in FIG. Samples of tape core wires with different structures and coating resin viscosities 1. Sample 2 was prototyped.

As a comparative example, sample 1. With the same structure as Sample 2, Conventional Example 1 in which the outermost layer coating was not subjected to surface treatment as an example of a conventional manufacturing method, and Conventional Example 2 in which talc powder of another example was applied to the outermost layer coating surface were prepared.

Sample 1 according to the invention. Conventional example of sample 2 and comparative example],
Static friction coefficient of the surface of the tape core wire of Conventional Example 2 and Sample 1
．． Sample 2. Conventional example 1. Third example using conventional example 2
Table 1 shows the results of measuring the transmission characteristics of the Sveza cable shown in the figure after it was made into a cable. Note that the prepared sample 1. Sample 2. Conventional example 1. Conventional example 2 is both 15
The transmission loss of a product with a length of 00 m after being made into a cable is a measured value at an optical wavelength λ=i55 μm.

Table 1 As can be seen from the results shown in Table 1, both Sample 1 and Sample 2 manufactured according to the present invention had unevenness uniformly formed on the coating resin surface over the entire length, and the coefficient of static friction was small. The transmission loss after making the cable was also low and good.

There are also no particular problems in handling.

On the other hand, Conventional Example 1 which was not subjected to surface treatment as a comparative example had a large friction coefficient, and a slight increase in transmission loss was observed after being made into a cable. Conventional Example 2, in which talc powder was applied to the coating surface, had a small coefficient of friction and no increase in transmission loss was observed after being made into a cable, which was good; however, when applying talc,
The process of applying it uniformly to the surface was difficult, and in addition, dust was generated, creating problems in the working environment.

As four examples of optical fiber strands produced by the manufacturing method of the present invention, Samples 1 to 4 having different coating resin viscosities were experimentally manufactured using the optical fiber strand die shown in FIG. 2.

As a comparative example, static friction was measured for Samples 1 to 4 according to the present invention, which have the same structure as Samples 1 to 4, but are an example of a conventional method in which no treatment is applied to the outer peripheral coating surface, and in addition to the conventional single-core optical fiber strand. The coefficients and transmission characteristics were adjusted. The results are shown in Table 2.

The manufactured samples 1 to 4 and the conventional example are all products with a length of 2000 m, and the transmission characteristics are based on the wavelength of light λ-1, 5.
The transmission characteristics were measured at temperatures of 23°C and -40°C. Example 2: An urethane acrylate-based ultraviolet curable resin was used as the optical fiber coating resin, and the resin was applied to the outer periphery of a bare glass fiber with a diameter of 125 μmψ. As can be seen from the results in Table 2 for the structure shown in Figure 1, in which the diameter is approximately 240 to 25071 mφ, all of Samples 1 to 4 manufactured according to the present invention have Uniform unevenness is formed on the coating resin surface, and the coefficient of static friction is small even when using resins with different viscosity, and the transmission characteristics are good from room temperature to low temperatures, and the transmission characteristics are equivalent to those of conventional examples. It is obtained by applying a resin with a resin viscosity of a seed, and is suitable for manufacturing. Furthermore, from the results in Table 2, the unevenness formed on the surface of the resin coating layer is more uniform when using a high viscosity resin than when using a low viscosity resin. For example, when tension fluctuation occurs, local distortion remains in the optical fiber, degrading transmission characteristics. On the other hand, in Sample 1 manufactured according to the present invention, no strain remained in the optical fiber even when tension fluctuation occurred, and it was confirmed that there was no problem in terms of transmission characteristics.

〔Effect of the invention〕

As explained above, in the method for manufacturing a resin-coated optical fiber of the present invention, in the step of coating an optical fiber with a resin, the coefficient of static friction is reduced by forming irregularities on the outer periphery of the coating layer when applying the coating resin. , it is possible to realize an optical fiber unit structure with low transmission loss after being made into a cable, there is no increase in the number of manufacturing steps, and the method is extremely effective as a method for manufacturing a resin-coated optical fiber with excellent productivity and transmission characteristics.

[Brief explanation of the drawing]

It can be seen from FIGS. 1a and 1b that the coated optical fiber manufactured by the manufacturing method of the present invention has a small optical static friction coefficient and a small tape fiber, and is excellent in bending properties. Furthermore, in this example, sample 1 prototyped according to the present invention
For the conventional example, we investigated the transmission characteristics due to tension fluctuations during winding of the optical fiber wire. The results are shown in Table 3. Table 3 is a cross-sectional structural diagram of a fiber strand, and Figures 2a and 2b are structural explanations of a tape core die and an optical fiber strand die, which are examples of the optical fiber coating die applied to the manufacturing method of the present invention. 3 are cross-sectional structural diagrams of a tape core spacer cable using optical fibers. DESCRIPTION OF SYMBOLS 1...Glass, 2...Optical fiber, 3...Coating layer, 4...Tape core wire, 5...Optical fiber wire, 40
...Dice for tape core wire, 50...Dice for optical fiber bare wire, 31...Grooved spacer, 32...Groove, 3
3... Optical fiber unit, 34... Pressure wrapping tape, 35... Cable sheath, 36... Tensile body patent applicant Sumitomo Electric Industries Co., Ltd. agent Patent attorney Tama Mushi Kugobe 4-tape core wire 5. Optical fiber strand Figure 40: Cross-sectional structure of coated optical fiber manufactured by the manufacturing method of the present invention; Figure 40; Die for tape core wire

Claims (3)

[Claims] (1) In a method of manufacturing a resin-coated optical fiber by coating an optical fiber with a resin, the step of coating the optical fiber with a resin includes a step of forming irregularities on the surface of the outer peripheral coating layer of the resin-coated optical fiber. A method for manufacturing a resin-coated optical fiber, characterized by: (2) The step of forming irregularities on the surface of the outer peripheral coating layer of the resin-coated optical fiber comprises a step of inserting the resin-coated optical fiber through a die of a resin coating device having irregularities on the inner surface of the die. The method for manufacturing a resin-coated optical fiber according to claim 1. (3) The method for manufacturing a resin-coated optical fiber according to claim 1 or 2, wherein the resin-coated optical fiber is made of a tape core in which a plurality of optical fibers are coated with a common coating.