JPS6191046A - Production of bunch-type light-transmission material - Google Patents

Abstract

PURPOSE:To prevent the deformation and the lowering of the strength of an optical fiber and to improve the transmission characteristics and dimensional accuracy, by separately coating plural optical fibers arranged in parallel and integrating the primary-coated optical fibers by secondary coating. CONSTITUTION:A plurality of preform rods 21, 22 placed in parallel keeping a space therebetween are drawn simultaneously to obtain a plurality of optical fibers 23, 24. The circumferences of the fibers 23, 24 are coated with primary coating layers 28, 29 to obtain primary-coated optical fibers 25, 26. The fibers 25, 26 are bundled, and integrated together by the secondary coating layer 30 applied to the circumference of the bundle.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application 1 The present invention relates to a method for manufacturing a bunch-type coated optical transmission body suitable for use in high-density optical cables.

I Conventional Technology j An optical transmission body called a bunch fiber is a type of optical fiber, but from a structural perspective, it consists of multiple ready-made optical fibers with a core and cladding bundled together. Since these are integrated, it is suitable for constructing high-density optical cables.

FIGS. 3 and 4 illustrate conventional examples of bunch-type coated optical transmission bodies with two cores, and these will be briefly explained below.

The ones in Figure 3 are core la, 1b and cladding 2a, respectively.
, 2b are circumscribed with each other, and a plastic coating layer 4 integrally covers these optical fibers 3a, 3b.

In the case of FIG. 3, depending on the coating layer 4, each optical fiber 3a,
3b is focused, but these optical fibers 3a, 3
b are simply circumscribed without being fused (or bonded), and the optical fibers rub against each other at the circumscribed portion and are damaged, causing strength deterioration.

The one in Figure 4 is the cladding 2a of each party's fibers 3a and 3b.
, 2b are fused to each other, whereby the optical fibers 3a,
3b is focused, so there is no problem of scratches as described above, but such a bunch-type coated optical transmitter also has problems due to its manufacturing.

In other words, the bunch-type coated optical transmission body shown in Fig. 4 is manufactured by bundling and spinning a plurality of preform rods, but in the process of spinning and fusing each optical fiber, these optical fibers are pressed against each other. A matching force acts, which brings the optical fibers into close contact with each other.

The temperature at this time is high and each optical fiber is softened, so the cladding, which is initially in line contact between the adjacent parts of the optical fibers, loses its shape while exhibiting a surface contact state due to the pressing force. The deformation at this time spreads to the core.

In this way, the optical fibers 3a and 3b, which have such distortion that the cores 1a and 1b are deformed, have poor transmission properties as well as strength, and since each preform rod is spun at the same time, the optical fibers obtained in the fused state are The cross-sectional shape is dumbbell-shaped, with a short axis diameter and a long sleeve diameter, making it difficult to control both axis diameters simultaneously, making it impossible to obtain a bunch-type coated optical transmission body with high dimensional accuracy.

Problems to be Solved by the Invention In view of the above problems, the present invention provides a method for manufacturing a bunch-type coated optical transmission body that does not cause deformation or strength deterioration of optical fibers, and satisfies high transmission characteristics and dimensional accuracy. This is what we are trying to provide.

"Means for Solving the Problems" The method of the present invention involves simultaneously heating and stretching a plurality of preform rods arranged in parallel without contacting each other to produce a plurality of optical fibers, and then A primary coat is formed on the outer periphery of the primary coated optical fiber,
Thereafter, these primary coated optical fibers are bundled and a secondary coat is formed around the bundle, and each of the primary coated optical fibers is integrated by the secondary coat to obtain a bunch type coated optical transmission body.

T effect j In the case of the method of the present invention, each optical fiber is kept in a non-contact state from the spinning process to the end of the primary coating process. There is no pressing force between the optical fibers, so there is no deformation of the core and cladding, and the spinning state of each optical fiber can be controlled individually to improve their dimensional accuracy.Furthermore, it is possible to form a secondary coat. 1 each
When integrating the next coated optical fibers, the primary coat has already been formed between the optical fibers, so there is no strength deterioration due to contact between the optical fibers, and overall there is no deformation of the optical fibers, no strength deterioration, etc. transmission characteristics,
A bunch-type coated optical transmission body that satisfies dimensional accuracy can be obtained.

``Example 1'' Hereinafter, regarding an example of a bunch type optical transmission body according to the present invention,
This will be explained with reference to the drawings.

In FIG. 1, 10.11 is a known feeding mechanism equipped with a screw shaft and a clamp member that is moved up and down via the screw shaft, and 12 is a spinning furnace equipped with a ring-shaped heater 13 inside. be.

14 and 15 are outer diameter measuring devices located below the spinning furnace 12, 16 is a coater of a spray set located below the outer diameter measuring device 14 and 15, and 17 is a coating device 1.
B and a pair of curing furnaces, 18 is a die-type coater disposed below the curing furnace 17, 19 is a coater 1B and a pair of curing furnaces, and 20 is a take-up machine.

21 and 22 are quartz-based preform lofts equipped with a core glass layer and a cladding glass layer.

When carrying out the method of the present invention in FIG. 1, the preform rods 21.22 are clamped by the feed mechanism 10.11, and in the outgoing clamped state, the preform rods 21.22 are juxtaposed without contacting each other.

The preform rods 21 and 22 are fed into the spinning furnace 12 at a low speed through mutually synchronized feeding mechanisms 1O111, where they are heated and softened sequentially from the lower end by the heater 13, and the heated and softened preform rods 21 The lower ends of the optical fibers 23.22 are pulled out at high speed to become optical fibers 23.24, and then the optical fibers 23.24 pass through an outer diameter measuring device 14.15 to measure their outer diameters.

After measuring the outer diameter, an uncured primary coat is formed by spraying an ultraviolet curable or thermosetting resin (uncured) onto the outer periphery of each optical fiber 23, 24 via a spray set coater 16. The primary coat is cured by receiving curing energy in the next stage curing furnace 17, thus obtaining a primary coated optical fiber 25.2B.

In this way, until the primary coated optical fibers 25.2B are obtained, they are in a non-contact state with each other, so the optical fibers 23.24 do not come into direct contact with each other, and therefore, these optical fibers 23. .24 variant,
No damage will occur.

Next, the primary coated optical fibers 25.2G are introduced into the dice-shaped coater 18, where the respective primary coated optical fibers 25.2B merge with each other to form a converged state, and these primary coated optical fibers 25. On the outer circumference of .28,
The ultraviolet curable or thermosetting resin (uncured) in the coater 18 is applied to form an uncured secondary coat, and the focused primary coated optical fiber 25.2B passes through the coater 18. When it enters the next stage curing furnace 19, the secondary coat receives curing energy and is cured, thus obtaining a predetermined bunch-type coated light transmitting body 27.

At this time of focusing coating, since a primary coat has already been formed on the outer periphery of the optical fibers 23 and 24, the optical fibers will not be damaged by the focusing.

Thereafter, the bunch-type coated optical transmission body 27 is wound up by a winding machine (not shown) via a take-up 920.

FIG. 2 is a sectional view of a bunch-type coated optical transmission body 27 manufactured by the method of the present invention described above, in which 28.2θ is a primary coat and 30 is a secondary coat.

The thickness of the primary coat 28.29 is, for example, 1~
The thickness of the secondary coat 30 is approximately 10 g, and the secondary coat 30 is made thicker than the primary coat 28 and 29.

In the illustrated example, two optical fibers are used as a bunch type coated optical transmission body.
Although a two-core type is shown, a bundle-type coated optical transmission body having three or more cores in which three or more optical fibers are bundled can also be manufactured in the same manner as described above.

In the illustrated embodiment, when controlling the outer diameter of the optical fiber 23, 24, the pulling plate speed by the pulling machine 20 is kept constant, and the measurement signal from the outer diameter measuring device 14, 15 is sent to the sending mechanism 1.
0.11 to the speed control system to control these feed mechanisms 10.
11, that is, the feeding speed of the preform rods 21 and 22, may be adjusted as appropriate.

The preform rows 21 and 22 can also be clamped and fed into the spinning furnace 12 by a single feeding mechanism, in which case only one outside diameter measuring device may be used.

The primary coats 28 and 29 can be formed by a coating method other than the spray method, such as a die coating method, but the spray method is preferable because it can form a thin primary coat and does not damage the optical fiber. .

A coating layer made of thermoplastic resin may be formed on the outer periphery of the bunch-type coated optical transmitter 27 obtained as described above, and the coating layer may be formed in tandem with the manufacturing method shown in FIG. It is formed in a separate process from the manufacturing method of .

As explained above, when using the method of the present invention, the spinning process and coating process are skillful, and these processes are rationally combined, so there is no deformation or strength deterioration of the optical fiber. Moreover, a bunch-type coated optical transmission body that satisfies high transmission characteristics and dimensional accuracy can be manufactured.

[Brief explanation of drawings]

FIG. 1 is a sectional view schematically showing an embodiment of the method of the invention;
The figure is a sectional view showing a bunch-type coated optical transmission body manufactured by the method of the present invention, and FIGS. 3 and 4 are sectional views showing conventional examples of bunch-type coated optical transmission bodies. l0111...Feeding mechanism l2...Spinning furnace 13, fist...-Heater 14.15...Outer diameter measuring device lθ...Coating device 17, fist...Curing furnace 18... ... fist coach ink machine 19 ... war hardening furnace 20 ... take-up machine 21.22 ... Φ preform rod 23.24 ... optical fiber 25, 28 - ... primary coated optical fiber 27...Bunch type coated optical transmission body 28.29...Primary coat 30...Secondary coat Agent Patent attorney Yoshio Saifuji Figure 2

Claims (2)

[Claims] (1) A plurality of preform rods arranged in parallel without contacting each other are simultaneously heated and stretched to create a plurality of optical fibers, and then a primary coat is formed on the outer periphery of these optical fibers for primary coating. Optical fiber and then
Bunch-type coated optical transmission characterized in that these primary coated optical fibers are bundled to form a secondary coat around the bundle, and each primary coated optical fiber is integrated by the secondary coat to obtain a bunch-type coated optical transmission body. How the body is manufactured. (2) A method for manufacturing a bunch-type coated optical transmission body according to claim 1, wherein the primary coat is formed by a spray method.