JPH05181032A - Fiber clamping for uniform coating of thin film for high-strength connection - Google Patents

Abstract

PURPOSE:To obtain the fiber clamping device for coating ribbon fibers with a UV curing resin for the purpose of high-strength connection of the ribbon fibers coated at a uniform thickness between the ribbons in the fibers. CONSTITUTION:Two analogous fiber clamps 2, 3 are used to directly clamp the original coating parts above and below the exposed parts of the fibers, by which the spacings-between the fibers f1 to f8 are held at the certain spacings of the coating from the beginning of the fiber ribbons 4. These two fiber clamps 2, 3 are mounted onto fiber clamp guides G1, G2 of a fiber clamp stand 1 for simultaneously and mechanically clamping the fibers with two pieces by using magnetic force. As a result, the linearity of the fiber ribbons is maintained without arraying the fiber clamps even if the type of the fibers to be coated or the number of the fibers varies. The fibers are easily mountable and removable to and from the fiber clamp guides by utilizing magnetic force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a uniform ultraviolet curable resin thin film (hereinafter, UV curable resin thin film) on each fiber when connecting each fiber in a fiber ribbon and each fiber in a mating fiber ribbon. The present invention relates to a uniform thin-film coating fiber clamp device for high-strength connection, which is suitable for increasing the strength of the connection part by coating (hereinafter, referred to as).

[0002]

BACKGROUND OF THE INVENTION In a typical submarine optical cable system,
Repeater stations are typically 70 to 200 km away. At present, the length of each individual optical fiber is at most 50 km.
Since there are only a few, you have to connect optical fibers to make a longer cable. These connecting parts must withstand stresses such as relatively high tension during cable production and cable laying.

In the conventional connection method, the strength at the connection point is very weak. Generally, the strength of an optical fiber coated with 125 μm is about 70 N (Newton), but it drops to about 7 N after splicing. The primary cause of this is believed to be mechanical damage to the bare fiber in contact with peripheral members such as blades for stripping coatings, blades for cutting or V-grooves for alignment. These mechanical damages cause micro-scratches on the surface of the fiber, resulting in strong local stresses. In addition, when additional stress is concentrated on these scratches when the optical fiber is made into a cable or handled, the optical fiber is easily broken.

At present, various connection technologies have been developed to obtain high strength technology. For example, Miyajima proposes a method in which after making a conventional connection, the surface of the fiber is exposed by etching with hydrofluoric acid to expose it, and then the connection point is covered. This is described in detail in "Long-distance fiber having high strength connection" by Miyajima et al. (Electronic Letter, Vol. 17, 670-672, September 1981). In addition, Clause proposed flame fusion connection using hydrogen chloride gas, and used UV curing material to save the connection point. Regarding this, J. T. `` Fiber Splices with Perfect Fiber Strengths o
f 5.5 GPa V> 0.01 ”(Electronics Letters, vo
l.21, N.12, Jun.6,1985 PP.533-535).

As a more general method, a non-contact method is used. Bare fiber must be handled with great care during the entire splicing process, from pre-splicing to post-splicing, without any mechanical damage.
For example, in Yamada et al., "Arc Fusion Splicer with Profile Alignment System for High Strength Low Loss Submarine Optical Cables" (IEEE, 1986), the fiber coating is chemically removed using methylene chloride. The fiber is also clamped for cleaving, aligning and final arc fusion splicing the cladding. The connection portion is coated again with an ultraviolet curing resin (hereinafter referred to as a UV curing resin) for protection. In 1990, Arthur R. Tynes, "Method and apparatus for making high strength connections in optical fibers" (US Pat. No. 4,958,905)
No.), the optical fiber also has its coating chemically removed, but the alignment is made by a V-groove block coated with a non-friction material and the connection is made by heating a tungsten or tantalum ribbon. Utilizes heat. Moreover, the connection part is again covered with UV curable resin for protection.

Further, for example, K. “1.55 by Osaka, etc.
Development of high-strength connection technology using field for μm diffusion-shifted fiber ”(IWCS Proceedings
1988) another contactless method has been proposed. According to this, the fiber coating is removed with a hot stripper,
Bare fiber is approximately 5μ (excluding a few mm from the cut end)
The UV curable resin thin film is coated to a thickness of about m. The coated fibers are then spliced with a conventional arc discharge fusion resin machine and the spliced fibers are reinforced with heat shrink tubing.

The methods described herein are all applicable to high strength connections to a single fiber. However, for high strength connections of fiber ribbons, the coating of fiber ribbons cannot be chemically removed. One practical removal method is to use a hot stripper. Moreover, the fiber ribbon cannot clamp the coating for alignment.

At present, as a fiber aligning means applicable to the multi-core fusion splicing, only a highly accurate V groove block is used. That is, the pair of fibers to be connected are arranged such that the clad portions are arranged on the V-groove block and aligned, and the V-groove block is fixed so as not to move in any direction. Therefore, if the V-groove blocks were not aligned and were used to clamp the coated portion of the fiber ribbon, there would be excessive alignment error (eg, due to fiber curl) for individual fibers, resulting in large splice losses. will do.

Further, when the fiber ribbon is aligned with the V-groove block coated with a non-abrasive material, dust on the V-groove, S
Micro-contaminants such as deposits of iO ₂ vapor can cause mechanical damage to the bare fiber, which causes microscratches on the fiber surface which results in a significant loss of strength.

In view of the above circumstances, one of the effective methods for realizing a high strength fiber ribbon connection is to remove the coated portion from the original fiber ribbon with a hot stripper and then mechanically damage it. In order to prevent this, the bare part where the coating is removed is coated with a UV-curing resin thin film with a thickness of about 5 μm, and then the conventional multi-core fusion splicing that uses a highly accurate V groove block for fiber alignment at the time of splicing. Connection using a machine. Then, the connection points are recoated with UV curable resin for protection. In single fiber thin film coatings, the linearity of the exposed bare fiber to be coated is less important. This is because, as described above, most effective single fiber splicers have the XY alignment function of the core or cladding of the fiber, so that the non-linearity of the thin film caused by the non-linearity of the fiber is caused. Is because it does not have a serious connection result. Therefore, only the lower part of the single fiber needs to be vertically clamped by a fiber clamp means or the like.

[0011]

However, in the thin film coated fiber ribbon 100 as shown in FIG. 3, if the exposed fiber 101 is not clamped to maintain its linearity, the UV curable resin The adhesive force will cause a bridge 102 between the fibers 101. Once the bridge 102 is formed on the fiber ribbon 100, it cannot be used for connection. For thin film coatings of fiber ribbons, if each fiber is clamped with the spacing between the fibers wider or narrower than the spacing before coating, the spacing between the fibers after coating thin may be less than that before coating. It becomes narrower and it becomes impossible to secure the initial interval. As a result, trying to align the fiber ribbon with the correct V-groove block would be very difficult. Therefore, the fiber ribbon thin film coating clamping device will be less able to maintain the initial spacing throughout the entire coating process.

In the conventional clamping method, a two-individual fiber clamp is usually mounted on a thin film coating apparatus to clamp the exposed fiber upper side and the exposed fiber lower original fiber ribbon coating portion. Careful alignment of the two fiber clamps is required to maintain the linearity of the exposed fiber. Further, each time the type of fiber ribbon to be coated or the number of fibers in the ribbon is changed, another thin film clamp must be mounted on the thin film coating device, and each time the fiber clamp needs to be aligned. One clamping method involves clamping the upper side of the exposed fiber with a fiber clamp with precise V-groove blocks to maintain the initial fiber-to-fiber spacing. However, such an accurate V
The use of groove blocks is costly and it is not easy to vertically position the exposed fiber on the V groove blocks. Therefore, an object of the present invention is to provide a fiber clamp device for uniform thin film coating for high-strength connection, which can coat a uniform thickness of coating between fibers for high-strength connection of fiber ribbons. Is.

[0013]

That is, the present invention has a fiber clamp stand having a wall surface arranged in the vertical direction and provided with an opening for irradiating a light ray for curing a thin film coating on the wall surface. The fiber clamp guide is provided by sandwiching the opening of this fiber clamp stand so as to face the upper and lower edges of the opening, and the fiber clamp guide is fitted and attached to remove part of the fiber ribbon coating. A plurality of bare exposed bare fibers to clamp the coated portion of the bare fibers for placement in the opening. Further, according to the present invention, the upper and lower fiber clamps are magnetically attracted to the fiber clamp guide.

[0014]

Two similar fiber clamps are used to clamp the original coating directly above and below the exposed portion of the fiber, with the initial spacing between the fibers being equal to the initial coating of the fiber ribbon. Since the fibers are held, uniform thin film coating can be performed on each fiber as long as the fibers in the ribbon are uniformly coated from the beginning.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. As shown in FIG. 1, a fiber clamp device for uniform thin film coating according to the present invention (a part of the bare fibers f1 to f8 to be exposed and the original coating C1 on the upper and lower sides of the bare fibers f1 to f8 respectively exposed). , C2) is a protruding fiber clamp guide G1.
And a fiber clamp stand 1 comprising G2, an attachable lower fiber clamp 2 for holding the (first) coating of the fiber ribbon below the exposed fiber, and a fiber ribbon 4 above the exposed fiber. It consists of a removable upper fiber clamp 3 for holding the (first) coated part.

The fiber clamp stand 1 is made of an arbitrary magnetic material such as iron, and has a wall surface 1A standing upright in the vertical direction. The wall 1A has an opening 1B.
The lower fiber clamp 2 can be easily attached and detached therefrom. Therefore, it is very easy to use, and is particularly effective for different types of fiber ribbons to be coated and different numbers of fibers.
Further, clamp guides G1 and G2 are formed on one surface of the wall surface 1A in a straight line in the vertical direction with the opening 1B sandwiched therebetween. The upper and lower protruding fiber clamp guides G1 and G2 are manufactured mechanically at the same time, and their arrangements match each other with high precision. As a result, when the upper and lower protruding fiber clamps 2 and 3 are attached to the fiber clamp guides G1 and G2 in a fitted state, the exposed fibers f1 to f8 are already in a good alignment. .. In order to secure stable positioning in the vertical direction at the same time when the fiber clamps 2 and 3 are attached to the fiber clamp guides G1 and G2 and are attracted by magnetic force, a locking step is provided on the wall surface 1A near the fiber clamp guides G1 and G2. Portions 1B and 1C are formed.

The lower fiber clamp 2 uses the conventional fiber holder for holding the fiber ribbon 4 as it is for connection by the fiber ribbon splicing machine.
A groove 2A (which may be a dovetail groove) for fitting with the protruding fiber clamp guide G1 is formed. There is a small magnet inside the lower fiber clamp 2 so that it can be easily attached to or detached from the surface of a magnetic material such as iron. Since the offset of the fiber center of the lower fiber clamp 2 varies depending on the type of fiber ribbon to be clamped and the number of fiber ribbons, the upper fiber clamp 3 should be designed in the same shape (that is, the fiber ribbon to be clamped). The fiber center offset should vary depending on the number of optical fibers). Therefore, the type and number of fiber ribbons to be coated should correspond to the set of upper and lower fiber clamps. The upper fiber clamp 3 also has a small magnet inside so that it can be easily attached to and detached from the fiber clamp guide G2.

From the beginning of the fiber ribbon 4 coatings C1, C
Since the two portions are clamped by the fiber clamps 2 and 3, respectively, the distance between the exposed fibers is kept to be the same as the fiber distance of the portion coated from the beginning of the fiber ribbon. This eliminates the need for expensive V-groove blocks to maintain fiber spacing. In short, the fiber clamp device for uniform thin film coating in this embodiment has a simple structure, is low in cost, is easy to operate, and can maintain linearity. Very effective when kept the same. Further, even if the type of fiber ribbon to be coated changes or the number of fibers changes, the alignment work of the fiber clamp is not particularly required. Any of the techniques described herein can be used when the fiber is to be clamped vertically according to the present invention.

When applying the thin film coating resin 5 (for example, UV curing resin) in this embodiment, a substantially U-shaped holder 6 is used and the thin film coating resin 5 is filled with the slots 6A.
Then, the holder 6 may be moved vertically downward as shown in FIG.

[0020]

As described above, according to the fiber clamp device for uniform thin film coating for high-strength connection of the first aspect of the present invention, the original coating is directly clamped above and below the exposed portion of the fiber. Two similar clamps have been used to maintain the fiber de-spacing the same as the fiber ribbon's initial coating spacing so that the fibers in the ribbon are uniformly coated from the beginning. As long as it is possible to carry out a uniform thin film coating on each fiber, and thus a high-strength connection of ribbon fibers can be achieved. That is, according to the present invention, two fiber clamps are mechanically mounted on the fiber clamp guides of the fiber clamp stand, even if the types of fibers to be coated are different or the number of fibers is different. The fiber straightness can be maintained without the need to purposely align the two fiber clamps. According to the fiber clamp device for uniform thin film coating for high-strength connection of claim 2 of the present invention, since the fiber clamp is attached to the fiber clamp guide by utilizing magnetic force,
Easy to install and position.

[Brief description of drawings]

FIG. 1 is a perspective view showing an entire fiber clamp device according to the present invention.

FIG. 2 is an explanatory diagram showing a state in which a thin film is coated on a fiber ribbon by using the apparatus shown in FIG.

FIG. 3 is an explanatory diagram showing a state in which a bridge is formed on each fiber in a ribbon coated with a UV curable resin.

[Explanation of symbols]

 1 Fiber Clamp Stand 2, 3 Clamp 4 Fiber Ribbon 5 UV Curing Resin 6 UV Curing Resin Holder 6A Slots f1 to f8 Bare Fiber C1, C2 Original Coating G1, G2 Fiber Clamp Guide

Claims (2)

[Claims] 1. A fiber clamp stand having a wall arranged vertically and provided with an opening for irradiating a light beam for curing a thin film coating on the wall, and an opening sandwiching the opening of the fiber clamp stand. A fiber clamp guide is provided so as to face the upper and lower edges of the opening, and a plurality of bare fibers exposed by partially removing the coating portion of the fiber ribbon are attached by fitting the fiber clamp guide to the fiber clamp guide. A fiber clamp device for uniform thin film coating for high strength connection, comprising upper and lower fiber clamps for clamping the coated portion of the bare fiber for placement in a section. 2. The fiber clamp device for uniform thin film coating as claimed in claim 1, wherein the upper and lower fiber clamps are magnetically attracted to the fiber clamp guide.