JP2011102915A - Manufacturing method of optical fiber, and the optical fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an optical fiber that has an outside diameter which can pass through coloring dice, and moreover, that has a protective coating in which peeling or breaking does not occur, and to provide the optical fiber by the manufacturing method. <P>SOLUTION: After the glass fiber 11 is exposed, by removing a fiber coating 12 at an end at a side where a pair of optical fibers are connected, end surfaces of the glass fiber 11 are fused and bonded; a protective resin 14 is casted around the exposed portion of the glass fiber 11 for protection; and when the fiber coating 12 of the optical fiber end is removed, the shape of a coating edge 12a of the fiber coating 12 is made into a tapered shape 15, and the protective resin 14 is casted so as to include the coating edge 12a. Additionally, the exposed portion of the glass fiber 11 is colored, by using the coloring dice, after being protected with the protective resin 14. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical fiber manufacturing method in which optical fibers are fusion spliced into a long optical fiber.

  In response to a request from a user, an optical fiber having a length of several tens of kilometers, such as a submarine cable, is manufactured. Such a long optical fiber is usually formed by fusion-connecting a plurality of optical fibers. In this case, it is required that peeling or cracking does not occur at the interface between the protective resin that protects the connecting portion and the original resin. For example, the techniques disclosed in Patent Documents 1 and 2 are known as satisfying such demands.

  FIGS. 4A and 4B are diagrams showing an example of a fusion splicing portion disclosed in Patent Document 1, in which the fiber coating 2 at the ends of a pair of optical fibers is removed to expose the glass fiber 1. The end faces of 1 are fused together. The fusion-bonded portion 3 and the fiber coating on both sides thereof are removed, and the bare glass fiber is covered and protected by the protective resin 4. The protective resin 4 is formed so as to substantially match the outer diameter of the fiber coating 2. In FIG. 4A, the end surface of the fiber coating 2 is a rough surface 5, and in FIG. 4B, the uneven surface 6 is used to strengthen the bonding between the fiber coating 2 and the protective resin 4 to suppress peeling and cracking. I am doing so.

  FIG. 4C is a diagram showing an example of the fusion splicing portion disclosed in Patent Document 2, and the protective resin 4 is formed to be thicker by several μm than the outer diameter of the fiber coating 2. The protective resin 4 is formed so as to have an overlapping portion 7 so as to cover the end of the fiber coating 2 somewhat, so that the end of the fiber coating 2 is not exposed. In addition, Patent Document 2 discloses a mold for molding the protective resin 4 and discloses a technique for preventing bubbles from remaining in the protective resin.

JP-A-10-68838 Japanese Patent Laid-Open No. 2002-120242

  As shown in FIGS. 4A and 4B, even if the joint surface of the fiber coating and the protective resin is rough or uneven, the coating thickness is about 60 μm. There is a limit to obtaining a joint with and is not sufficient. For this reason, as shown in FIG. 4 (C), a part of the protective resin covers the end of the fiber coating. However, when coloring after connection, if the fiber is formed with an outer diameter that passes through a colored die, the fiber There is a problem that the thickness of the protective resin of the overlapping portion 7 of the coating is thin, and the protective resin portion easily peels off when passing through the coloring die.

  For this reason, in many cases, the optical fiber is connected so as to have a predetermined length after coloring the optical fiber. In this case, after coloring the optical fiber strands, rewinding for the purpose of single length alignment, detection and removal of colored bumps, screening and the like, and then conducting a core inspection, then connecting the optical fiber to connect the optical fiber After winding, rewinding and core inspection are performed again for the same purpose as described above. For this reason, since the rewinding of the optical fiber is performed twice and the core wire inspection is also performed twice, there is a problem that the cost is increased and the lead time is increased.

  The present invention has been made in view of the above-described circumstances, and when the protective resin of the fusion spliced portion passes through the coloring die, it is peeled off (interface) between the protective resin of the fusion spliced portion and the original coating. An object of the present invention is to provide an optical fiber manufacturing method capable of reducing the occurrence of abnormalities during coloring so as not to cause cracking and enabling coloring after fusion splicing, and an optical fiber by the manufacturing method.

  The optical fiber manufacturing method according to the present invention and the optical fiber according to the manufacturing method are formed by removing the fiber coating at the end on the side where the pair of optical fibers are connected to expose the glass fibers, and then connecting the end faces of the glass fibers to each other. It is fusion spliced and protected by casting a protective resin around the exposed part of the glass fiber. When removing the fiber coating at the end of the optical fiber, the shape of the fiber coating is tapered, A protective resin is cast so as to include the covering. Moreover, after protecting the exposed part of a glass fiber with a protective resin so that the taper-shaped covering may be included, it colors using a coloring die.

  According to the present invention, it is possible to increase the thickness of the portion of the protective resin that is covered when the fiber is coated. As a result, it is possible to prevent the portion covered with the protective resin from being peeled off by passing through the coloring dies, and to form a long optical fiber having a predetermined length by fusion-bonding in a strand state before coloring the optical fiber. Later, coloring can be applied. As a result, the manufacturing process of the optical fiber can be shortened, and productivity and lead time can be improved.

It is a figure explaining the outline of the optical fiber manufactured by this invention. It is a figure explaining the outline of the manufacturing method of the optical fiber by this invention. (A) is a figure which shows the manufacturing flow by this invention, (B) figure is a figure which shows the manufacturing flow by a conventional method. It is a figure explaining a prior art.

  Embodiments of the present invention will be described with reference to the drawings. In the figure, 10 is an optical fiber, 11 is a glass fiber, 11a is a removal fiber, 12 is a fiber coating, 12a is a coating, 12b is a removal coating, 13 is a fusion splicing part, 14 is a protective resin, 14a is an overlapping part, Reference numeral 15 denotes a tapered surface, 16 denotes a recess, and 17a and 17b denote molding dies.

  As shown in FIG. 1, a long optical fiber manufactured according to the present invention is formed by fusion-connecting a plurality of short optical fibers 10. In the fusion splicing of the optical fibers, the fiber coating 12 at the ends of the pair of optical fibers 10 connected to each other is removed, and the glass fiber 11 is exposed. The end faces of the glass fibers 11 that have been bare by removing the fiber coating 12 are butted together, and the butted end faces are fused and connected by arc discharge or the like.

  Since the fusion splicing portion 13 and the bare glass fiber 11 in the vicinity thereof are easily damaged and mechanically weak, they are recoated with the protective resin 14. The protective resin 14 is an ultraviolet curable resin of the same type as that of the fiber coating. The protective resin 14 can be formed by casting using a molding die as disclosed in Patent Document 2 above.

  In the present invention, the coating 12a of the fiber coating 12 at the end of the optical fiber 10 is a tapered surface 15 having a coating diameter that decreases toward the end. Then, the protective resin 14 is molded so as to cover the portion 12a at the time of coating the tapered fiber coating. With this configuration, the end face of the covering 12a can be covered and not exposed. Further, since the fiber coating 12a is a tapered surface 15, the overlapping portion 14a covered by the protective resin 14 at the time of coating can be thickened, and the adhesion area at this portion can be increased. By making the surface rough, the adhesive force with the protective resin 14 can be increased. As a result, it is possible to form a strong bond without peeling or cracking at the time of coating the fiber coating 12a.

  As a specific example of the optical fiber connecting portion, the exposed length K of the glass fiber 11 of the fusion splicing portion 13 is about 10 mm, and the length L of the overlapping portion 14a of the protective resin 14 at the time of covering the fiber coating 12a is 4 mm. The total length M of the protective resin 14 is about 18 mm to 20 mm. If the outer diameter D of the fiber coating 12 of the optical fiber is 250 μm, the outer diameter E that is several μm larger than this is, for example, 255 μm.

  FIG. 2 is a diagram for explaining an example of a method for manufacturing the above-described optical fiber connection portion. As shown in FIG. 2A, the ends of a pair of optical fibers 10 to be connected to each other are drawn out. Next, as shown in FIG. 2B, in the vicinity of the end of the optical fiber 10, the outer periphery of the fiber coating 12 is cut into an arc shape in the longitudinal direction using a rotary tool T such as a router, and the arc-shaped recess 16 is formed. create. The recess 16 is shaved so that the fiber coating 12 remains so that the deepest portion of the center portion does not reach the glass fiber 11.

  Thereafter, as shown in FIG. 2C, the fiber coating 12 is cut in the vicinity of the center of the dent 16, the fiber coating on the end side is pulled out and removed as the fracture coating 12b, and the end portion of the glass fiber 11 is removed. Expose. Half of the dent 16 remaining on the glass fiber 11 is formed into a tapered surface 15 to form a fiber coating 12a. The bare glass fiber 11 exposed by the removal of the rupture coating 12b is cut at an excess portion as a removal fiber 11a so as to be a predetermined distance from the end of the fiber coating 12a. An end face is formed.

  Next, as shown in FIG. 2D, the exposed end faces of the glass fiber 11 are fusion-bonded by arc discharge or the like, and the pair of optical fibers 10 are physically and optically connected. For fusion splicing, a general fusion splicer is used to hold and fix the optical fiber coating, and then processing steps such as observation of the connection end face, cleaning, core alignment, arc discharge, and indentation are performed. After that.

Thereafter, as shown in FIG. 2 (E), the fusion splicing portion 13 and the vicinity thereof are protected. As described with reference to FIG. 1, the protective resin 14 covers the fusion splicing portion 13, the exposed bare glass fiber portions on both sides thereof, and the covering 12 a of the fiber coating. The protective resin 14 is made of the same type of ultraviolet curable resin as the fiber coating 12 and is formed as described above using the lower mold 17a and the upper mold 17b.
In addition, after this protection treatment, the protective resin 14 is deburred as necessary, a tensile test or loss measurement is performed on the fusion spliced portion, and if the connection treatment is poor, reconnection is performed. .

FIG. 3 is a diagram for explaining a manufacturing flow of a long optical fiber colored on the fiber coating of the optical fiber. FIG. 3 shows a typical flow. Depending on the situation, the rewinding may be performed twice or may be rewinded by the inspection NG after the inspection.
As shown in FIG. 3A, in step S1, a plurality of short optical fiber strands of a predetermined length that are not colored are prepared in a state of being wound around a bobbin.

Next, in step S2, in the state where each of the plurality of optical fibers is wound around the bobbin, the optical fibers at the upper ends of the bobbins are fused and connected by the above-described method, and a protection treatment with a protective resin is performed. A long optical fiber of a book is wound around a bobbin on one side.
Thereafter, the process proceeds to step S3, and the long spliced optical fiber is colored. The optical fiber is colored by passing the optical fiber strand through a coloring die, and the fusion spliced portion protected by the protective resin is also continuously colored.
Next, in step S4, the colored optical fiber is wound for the purpose of single length matching, detection and removal of colored bumps, screening, and the like. Thereafter, the colored optical fiber wound in step S5 is inspected (inspection such as OTDR of a series of optical fibers after connection), and the processing is completed.

FIG. 3B shows a conventional flow for the manufacturing flow of the optical fiber. In this case, step S01 is the same as step S1 in FIG. 3A, and a plurality of short optical fiber strands of a predetermined length that are not colored are wound in a state of being wound around a bobbin.
Next, in the next step S02, each prepared optical fiber is individually colored through a coloring die. In step S03, the colored optical fiber is wound up with another bobbin for the purpose of single length alignment, detection and removal of colored bumps, screening, and the like. In the next step S04, the wound colored optical fiber is inspected ( (Inspection of OTDR etc. of each bobbin before connection).

Thereafter, in step 05, the short colored optical fiber wound around another bobbin is fused and connected to each other at the upper opening of the bobbin, and subjected to reinforcement protection treatment with a protective resin. The optical fiber.
Next, in step S06, the connected optical fiber is wound around a bobbin capable of winding a predetermined long optical fiber. Thereafter, the colored optical fiber wound up in step S07 is inspected (inspection such as OTDR of a series of optical fibers after connection), and is completed.

  If the protective coating of the portion covered by the fiber is not thick regardless of the present invention, coloring after fusion splicing tends to cause peeling or cracking at the interface between the protective resin and the original resin. It is necessary to perform fusion splicing after coloring, which increases rewinding and inspection processes. For this reason, production man-hours increase and it becomes disadvantageous in terms of cost, and the lead time from the start of production to shipment becomes longer.

DESCRIPTION OF SYMBOLS 10 ... Optical fiber, 11 ... Glass fiber, 11a ... Removal fiber, 12 ... Fiber coating, 12a ... During coating, 12b ... Removal coating, 13 ... Fusion splicing part, 14 ... Protective resin, 14a ... Overlapping part, 15 ... Taper Shaped surface, 16 ... dent, 17a, 17b ... mold for molding.

Claims (3)

After removing the fiber coating at the end of the connection side of the pair of optical fibers to expose the glass fiber, the end faces of the glass fiber are fused and connected, and a protective resin is applied around the exposed portion of the glass fiber. An optical fiber manufacturing method for casting and protecting,
When removing the fiber coating at the end of the optical fiber, the shape of the fiber coating is tapered, and the protective resin is cast so as to include the coating. .   The method for producing an optical fiber according to claim 1, wherein after the exposed portion of the glass fiber is protected with the protective resin, the glass fiber is colored using a coloring die. The fiber coating at the end of the pair of optical fibers connected is removed, the exposed end faces of the glass fibers are fusion spliced, and the periphery of the exposed portion of the glass fibers is protected with a protective resin by casting An optical fiber,
An optical fiber, wherein the glass fiber is coated in a tapered shape, and the protective resin is cast so as to include the coated fiber.

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