JPH05333215A - Method for connecting optical fiber to chip for fixation - Google Patents

Abstract

PURPOSE:To stabilize the connection of an optical fiber with a chip for fixation and to improve the reliability by removing the jacket part of the connection end of the optical fiber, and then heating the jacket and performing stress reduction and adhesion. CONSTITUTION:A notch is made in a jacket surface at a boundary 12 between a jacket removed part 10 where a coated optical fiber 1 is exposed and a residual jacket part 11 by using a cutting edge 3 and the jacket removed part 10 is drawn to pull and tear a jacket layer 9 nearby the coated optical fiber 1 which is not notched, thereby drawing the removed jacket part 10 out. Shrinkage stress is left in the vicinity of the elongated part 4 of the residual jacket part 11, so the shrinkage stress in the residual jacket part 11 is relaxed by a heating process so that the length of the elongated part 4 becomes zero. In such a state, the exposed coated optical fiber 13 is inserted into a ferrule 5, the outer peripheral edge part of the exposed coated optical fiber 13 and the inner peripheral wall of the ferrule 5 are adhered with an adhesive, and one end surface 15 of the ferrule, the cutting surface of the residual jacket part 11, and the outer peripheral surface of the residual jacket part 11 in the vicinity of the cutting surface 14 are adhered with the adhesive 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for connecting an optical fiber having a protective coating to a fixing chip, and more particularly to bonding due to stress release due to temperature change after the bonding between the optical fiber and the fixing chip. The present invention relates to a method of connecting an optical fiber to a fixing chip that prevents peeling of a portion.

[0002]

2. Description of the Related Art A commonly used optical fiber has a thickness of 1
It is a wire with a small diameter of 00 μm or less, and is easily broken, so it is protected by a coating. This coating is not necessarily a single layer, and may be formed of several types of layers and the materials of the layers may be different. When connecting the optical fiber to a fixing chip such as an optical fiber connector with a ferrule or a grooved carrier, the coating of the connecting end is usually several mm to several c.
It is removed at a length of m, and the core (main body) of the optical fiber is exposed and processing such as adhesion is performed.

FIG. 2 shows an example of a conventional connection method for adhering the ends of the core 1 and the coating 2 of an optical fiber to a fixing chip.
In this connection method, the boundary 1 between the removal coating portion 10 and the residual coating portion 11 where the core 1 of the optical fiber (FIG. 2A) is to be exposed.
A cut is made from the coated surface of No. 2 with a blade 3 (FIG. 2B), tension is applied to the coated surfaces of the removed coating portion 10 and the residual coating portion 11 and the coating surfaces are pulled in opposite directions, and The coating layer 9 close to the core 1 is torn off to remove the unnecessary removed coating portion 10 (FIG. 2C).

In one conventional example shown in FIG. 2E, an exposed core 13 of an optical fiber is inserted into a ferrule 5 used for an optical fiber connector, and an outer peripheral edge portion of the exposed core 13 and an inner wall surface of the ferrule 5 are bonded with an adhesive. It is glued at 7. Further, one end surface (adhesive surface) 15 of the ferrule 5, the cut surface 14 of the residual coating portion 11 and the outer peripheral surface of the residual coating portion 11 near the cut surface 14 are bonded with the adhesive 7. During actual use, the other end surface 17 of the ferrule 5 and the tip surface 1 of the exposed core 13 are further used.
8 is ground to form a smooth coplanar surface perpendicular to the axis of the exposed core 13.

In another conventional example shown in FIG. 2G, the exposed core 13 of the optical fiber is inserted into the groove 19 of the grooved carrier 6 for connecting to an optical integrated circuit and the like, and the outer peripheral portion of the exposed core 13 and the groove. The inner wall surface of 19 is bonded with the adhesive 7. Further, one end surface (adhesive surface) 20 of the grooved carrier 6, the cut surface 14 of the residual coating portion 11 and the outer peripheral surface of the residual coating portion 11 close to the cut surface 14 are bonded with the adhesive 7. In actual use,
Further, the other end surface 21 of the grooved carrier 6 and the tip end surface 22 of the exposed core 13 are polished so as to form a smooth coplanar surface perpendicular to the axis of the exposed core 13.

[0006]

By the way, in the case where the optical fiber is connected to the fixed chip by the above-mentioned conventional method, as shown in FIGS. In addition, peeling may occur on the bonding surface 15 of the ferrule 5 or the bonding surface 20 of the grooved carrier 6 to generate the peeling portion 8. In rare cases, the core portion of the optical fiber exposed at the peeling portion 8 is generated. 23 was sometimes broken.

Even if such breakage does not occur, if the peeling portion 8 occurs, the fixed chip and the optical fiber may be bent suddenly at that portion, making precise and stable optical connection difficult. In addition, the ferrule 5, the grooved carrier 6 and the exposed core are
Precise and stable due to the fact that the tip surface does not become the same plane, the core of the optical fiber rotates from the original state inside the ferrule 5 or the groove, and their deviation fluctuates due to temperature changes. It was sometimes difficult to make a simple optical connection.

It is also conceivable that the adhesion between the inner wall surface of the ferrule 5 or the grooved carrier 6 and the outer peripheral edge of the exposed core may be separated. In this way, the peeling portion 8 is generated, and at that portion, the core portion 23
As a result of various experiments and research, it was found that it was based on the following reasons. That is, when the removal coating portion 10 is pulled out in FIG. 2C, the remaining coating layer 9 not cut by the blade 3 is torn off, but the residual coating portion 11 is pulled and stretched for that reason, and the removal coating portion 10 is stretched.
The extension 4 is formed as shown in FIG. The length of the extension 4 depends on the strength of the coating layer 9 left uncut by the blade 3. Adhesion to the ferrule 5 and the grooved carrier 6 was performed in the state in which the extended portion 4 was present. Therefore, the stress accumulated in the vicinity of the extension portion 4 of the residual coating portion 11 is released by the heating in the subsequent steps or the heating brought during use as a product, and the residual coating portion 11 is in the original state (extension portion). The length of 4 contracts to return to 0). When this contracting force is larger than the adhesive force on the adhesive surfaces 15 and 20, peeling occurs, and in some cases, the core portion 23 also breaks.

The object of the invention of claim 1 is to reduce the latent contraction stress in the vicinity of the extended portion 4 of the residual coating portion 11 remaining after the removal coating portion 10 of the optical fiber is removed, before bonding the optical fiber and the fixed chip. Another object of the present invention is to provide a method of connecting an optical fiber to a fixing chip, which is improved in stability and reliability of its adhesive portion. The object of the invention of claim 2 is to claim 1.
Another object of the present invention is to provide a connecting method for further stabilizing the method for connecting an optical fiber to a fixing chip.

[0010]

According to the invention of claim 1, the coating of the connecting end of the optical fiber is removed, the stress of the coating is relieved by the heating step, and then the optical fiber and the end of the coating are fixed. It is bonded to the chip with an adhesive. In the invention of claim 2, the heating step in claim 1 is below the maximum heat resistant temperature of the optical fiber, its coating and the adhesive,
In addition, the temperature is maintained above the maximum operating temperature of the fixing chip to which the optical fiber is connected.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will now be described with reference to the drawings. FIG. 1 shows a method of connecting an optical fiber and a fixed chip according to the first and second aspects of the invention. The parts corresponding to those of the conventional connection method shown in FIG.
Also, FIGS. 1A, B, C and D are shown in FIGS. 2A, B, C and D, respectively.
, And the processing steps are exactly the same, so they will not be repeated here.

FIG. 1D shows a state in which the coating (removal coating portion 11) on the connection end of the optical fiber is removed, and the residual coating portion 11 is shown.
A contraction stress is left in the vicinity of the extension 4 of the. In the present invention, the optical fiber in this state is heated. As a result, as shown in FIG. 1E, the contraction stress in the residual coating portion 11 is relaxed, that is, the length of the extension portion 4 becomes almost 0, and a stable state is achieved.

In one example shown in FIG. 1F, this extension 4
Of the exposed core 13 of the optical fiber in a stable state where the length of the
Is inserted into the ferrule 5, and the outer peripheral edge portion of the exposed core 13 and the inner wall surface of the ferrule 5 are bonded with the adhesive 7. Further, one end surface (adhesive surface) 15 of the ferrule 5, the cut surface 14 of the residual coating portion 11 and the outer peripheral surface of the residual coating portion 11 near the cut surface 14 are bonded with the adhesive 7.

In another example shown in FIG. 1G, the exposed core 13 of the optical fiber is inserted into the groove 19 of the grooved carrier 6 in a stable state where the length of the extension portion 4 is almost 0, and the outside of the exposed core 13 is inserted. The peripheral edge portion and the inner wall surface of the groove 19 are bonded to each other with the adhesive 7. In addition, one end surface 20 of the grooved carrier 6 and the cut surface 1 of the residual coating portion 11
4 and the outer peripheral surface of the residual coating portion 11 close to the cut surface 14 thereof are bonded with the adhesive 7.

In the embodiment of the method for connecting an optical fiber and a fixed chip according to the invention of claim 2, in the embodiment of the invention of claim 1, the heating step performed in the process of shifting from FIG. 1D to FIG. The temperature is not higher than the maximum heat resistant temperature of the optical fiber 1, its coating 2 and the adhesive 7, and is not lower than the maximum operating temperature of the fixing chip 5 or 6 to which the optical fiber is connected.

[0016]

As described above, according to the method of connecting an optical fiber to a fixed chip of the first aspect of the present invention, after the coating of the connecting end of the optical fiber is removed, the stress of the coating is applied by a heating process. Since the ends of the optical fiber and the coating are adhered to the fixing chip after the relaxation, the stability and reliability of the adhered portion are improved.

In the invention of claim 2, the heating step in claim 1 is performed at a temperature not higher than the maximum heat resistant temperature of the optical fiber, its coating and an adhesive, and not lower than the maximum operating temperature of the fixing chip to which the optical fiber is connected. Being retained, the stability and reliability of the bond are further improved.

[Brief description of drawings]

FIG. 1 shows each step of a method of connecting an optical fiber to a fixed chip according to the present invention, A is a view showing an optical fiber before processing, B is a view showing a state where a cut is made in a covering portion with a blade,
C is a drawing in which tension is applied to the coatings on both sides of the cut, and D is a drawing in which the coating at the connection end of the optical fiber is removed, and E is a drawing which shows the state of the optical fiber after thermal processing. , F
Is a connection diagram between the optical fiber and the ferrule of the optical fiber connector, and G is a connection diagram between the optical fiber and the grooved carrier.

2A and 2B show each step and a state after that according to a conventional connecting method of an optical fiber to a fixed chip, A is a view showing an optical fiber before processing, and B is a state in which a cut is made in a covering portion with a blade. The figure, C is a figure in which tension is applied to the coating portions on both sides of the notch and is pulled, D is a state in which the coating at the connection end of the optical fiber is removed, and E is the ferrule of the optical fiber and the optical fiber connector. , F is a view showing a state where an adhesive portion is peeled off after the connection between the optical fiber and the ferrule of the optical fiber connector, G is a connection diagram between the optical fiber and the grooved carrier, and H is a connection diagram.
FIG. 4 is a diagram showing a state in which an adhesive portion is peeled off after a lapse of connection between an optical fiber and a carrier with grooves.

Claims (2)

[Claims] 1. The coating of the connecting end of the optical fiber is removed, the stress of the coating is relieved by a heating step, and the optical fiber and the end of the coating are bonded to a fixing chip with an adhesive. How to connect an optical fiber to a fixing chip. 2. The heating step is performed at a temperature not higher than the maximum heat resistant temperature of the optical fiber, its coating and an adhesive, and not lower than the maximum operating temperature of the fixing chip to which the optical fiber is connected. 1. A method for connecting the optical fiber to the fixing chip according to 1.