JP3051524B2 - Joint between optical fiber and ferrule and method for manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spliced product of an optical fiber and a ferrule having an improved connection portion, and a method of manufacturing the same.

[0002]

2. Description of the Related Art FIG. 3 is a cross-sectional view of a conventional joint product of an optical fiber and a ferrule. As described above, the joined product is composed of the optical fiber 11, the ferrule 12, and the adhesive 13 from which the fiber core wire 11c is exposed at the distal end by removing the primary coating 11a and the secondary coating 11b.

[0003] The manufacturing steps (a) to (e) of this bonded article are as follows. (A) Perform fiber seasoning. This is a step of applying a temperature cycle to the optical fiber 11 to shrink the coating in advance (seasoning). Since the coating of the optical fiber shrinks depending on the temperature depending on the material, this shrinkage is minimized after bonding with the ferrule. Do it to keep it low.

Since this step is performed until the rate of shrinkage of the coating is reduced by the temperature cycle, the shrinkage occurs even after the completion of the joined product, although slightly, and when a temperature cycle is applied, the force is applied in the direction of the arrow in FIG. Is added.

It is not necessary to perform this step if the coating does not shrink due to a temperature change.

(B) Fill the inside of the ferrule 12 with the adhesive 13.

(C) Fiber strip portion (core wire 11)
Apply adhesive to c).

(D) Insert the optical fiber 11 into the ferrule 12.

(E) The adhesive is cured.

[0010] However, in the conventional bonded product, air remains inside the ferrule. When the bonded product after completion was halved, 50% of the bonded product was φ1 μm to φ200.
0 μm air remained. This air repeats thermal expansion and contraction when a temperature cycle is applied, and separates between the adhesive 13 and the ferrule 12 and between the secondary coating 11b and the adhesive 13, and the shrinkage of the primary coating 11a and the secondary coating 11b is also applied. Peeling proceeds. When such a joint is used, a loss failure occurs at an early stage, and finally, a crack and breakage of the fiber and a rear protrusion of the adhesive 13 occur as shown in FIG. As a result of the test, 10% of the joined articles in which the presence of the air was found had such a problem.

Conventionally, this problem was thought to be caused by a problem in the process of filling the ferrule with the adhesive, and that air remained, but this time, this problem was caused by the shrinkage of the coating caused by the shrinkage of the coating during fiber seasoning. It has been found that peeling is largely caused by peeling between the fiber core wire and the primary coating and between the primary coating and the secondary coating. In other words, if the coating of the optical fiber is peeled off, the filled adhesive expands during curing and presses on the optical fiber, and the air accumulated at the coating peeling portion in the optical fiber comes out of the fiber and becomes an air reservoir 14. Was formed. In addition,
When the fiber coating was subjected to 50 cycles and 200 cycles of the optical fiber with the secondary coating being Hytrel and the primary coating being a UV curable resin, the length of the peeling generated in the fiber was about 3 cm in 50 cycles, and about 3 cm in 200 cycles. 7 cm. In addition, the peel length here is
For convenience, it is the length L shown in FIG.

In order to solve the above problems, the present invention provides a spliced product of a ferrule and an optical fiber which is resistant to temperature change without leaving air in the ferrule, and a method of manufacturing the same.

[0013]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, according to the present invention, an optical fiber having a coating removed portion at an end is inserted into a ferrule and fixed with an adhesive filled in the ferrule. The spliced product is a spliced product of an optical fiber and a ferrule in which a coating stripping portion generated in the optical fiber is filled with an adhesive. Further, the manufacturing method is such that the coating of the end of the optical fiber is removed, an adhesive is applied to the remaining coating end surface of the end, and the coating peeling portion generated in the optical fiber by evacuation from the end side. After the adhesive is filled in the ferrule, the optical fiber is inserted into a ferrule and fixedly adhered.

[0014]

Since no adhesive has been previously filled into the coating stripping portion generated in the optical fiber, no air is trapped in the bonded product.

[0015]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a spliced product of a ferrule and an optical fiber according to an embodiment of the present invention.

The optical fiber 1 shown in FIG. 1 has a primary coating 1a,
A secondary coating 1b, a fiber core wire 1c, and a coating portion of the optical fiber 1 generated in the fiber seasoning process, which is located in the ferrule 3 and is filled with the adhesive 2, and thus the adhesive 2 As shown in FIG. 1, the optical fiber 1, which has been previously filled in the exfoliated portion 2, is inserted into the ferrule 3 and fixed with the adhesive 4 filled in the ferrule 3 to complete a bonded product.

Next, the step of filling the coating stripping portion of the optical fiber 1 with an adhesive will be described.

FIG. 2 is a cross-sectional view of an optical fiber for explaining a method of manufacturing a bonded product of the optical fiber and the ferrule. The manufacturing is performed in the following steps (a) to (f).

(A) In the fiber seasoning step, the optical fiber 1 from which the end coatings 1a and 1b have been removed is seasoned. (B) In the step of filling the adhesive 2, the adhesive 2 is applied to the coated end face of the optical fiber 1 as shown in FIG. 2, and the adhesive 2 is filled into the coating stripped portion of the optical fiber by vacuuming from the end side. I do. (C) Fill the inside of the ferrule 3 with the adhesive 4. (D) The adhesive 4 is applied to the fiber strip portion (core wire 1c). (E) Insert the optical fiber 1 into the ferrule 3. (F) The adhesive 2 and the adhesive 4 are cured.

Through the above steps, a joined product of the optical fiber 1 and the ferrule 3 according to one embodiment of the present invention is manufactured.

As described above, in the bonded product according to one embodiment of the present invention, the adhesive 2 is applied to the exfoliated portion located in the ferrule 3 among the exfoliated portions generated in the optical fiber 1 in advance in the step (b). By filling by evacuation, the air does not accumulate due to the pressure on the optical fiber 1 due to the expansion of the adhesive 4 in the step of curing the adhesive 4 in (f) as in the prior art. Further, by filling the adhesive in the coating peeling portion generated in the optical fiber, an adhesive force for preventing a backward force due to shrinkage of the coating due to a temperature change after completion of the bonded product can be obtained. Therefore, the problems of the prior art, such as connection loss due to temperature change, fiber breakage, and protrusion of the adhesive at the rear can be solved.

Incidentally, in the joined product manufactured according to the above-described embodiment, no defect such as loss failure, fiber crack, fiber breakage, or protrusion of the rear portion of the adhesive occurred.

In this embodiment, an example in which fiber seasoning is performed has been described, but the present invention is not limited to this. In other words, slight peeling occurs even when the coating is removed at the end of the optical fiber. The same effects as above can be obtained.

[0024]

According to the present invention, a joint product between an optical fiber and a ferrule and a method of manufacturing the same are filled with an adhesive in advance at a coating stripping portion generated in the optical fiber as described above, so that the ferrule is completed after the joint product is completed. No air pockets are generated, and thus no defects such as loss failure due to severe temperature changes, cracks and breaks in the fiber, and rear protrusion of the adhesive do not occur.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a joint product of an optical fiber and a ferrule according to an embodiment of the present invention.

FIG. 2 is a sectional view of an optical fiber showing one embodiment of the present invention.

FIG. 3 is a cross-sectional view of a conventional joined product of an optical fiber and a ferrule.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical fiber 1a Primary coating 1b Secondary coating 1c Fiber core wire 2, 4 Adhesive 3 Ferrule

Claims (2)

(57) [Claims] An optical fiber having an uncoated portion formed at an end thereof is inserted into a ferrule and fixed by an adhesive filled in the ferrule. A spliced product of an optical fiber and a ferrule, which is filled with an adhesive. 2. The coating on the end of the optical fiber is removed, an adhesive is applied to the remaining coating end face of the end, and the coating is peeled off from the end on the stripped portion generated in the optical fiber by evacuation. A method for manufacturing a joined product of an optical fiber and a ferrule, wherein the optical fiber is inserted into a ferrule and fixed by bonding after filling the adhesive.