JP2772346B2 - How to connect optical fiber to fixing chip - Google Patents

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 an adhesion caused by a stress change due to a temperature change after the connection between the optical fiber and the fixing chip. The present invention relates to a method for connecting an optical fiber to a fixing chip for preventing separation of a portion.

[0002]

2. Description of the Related Art The core of an optical fiber generally used is a thin wire having a thickness of several hundred μm or less and is easily broken and protected by a coating. This coating is not necessarily one layer, but may be formed of several types of layers, and the material of each layer may be different. When connecting this optical fiber to a fixing chip such as an optical fiber connector with a ferrule or a grooved carrier, the coating at the connection end is usually several mm to
It is removed with a length of several cm, and the core (main body) of the optical fiber is exposed and processed such as bonding.

FIG. 2 shows an example of a conventional connection method for bonding the ends of an optical fiber core 1 and a coating 2 to a fixing chip.
In this connection method, the boundary 1 between the removed coating 10 and the remaining coating 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 the blade 3 (FIG. 2B), and tension is applied to the coated surfaces of the removed coated portion 10 and the residual coated portion 11 and pulled in opposite directions to each other. The coating layer 9 near the core 1 is torn off to remove an unnecessary removal 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 portion of the exposed core 13 and an inner wall surface of the ferrule 5 are bonded with an adhesive. 7 is adhered. Further, one end surface (adhesive surface) 15 of the ferrule 5 and the cut surface 14 of the residual covering portion 11 and the outer peripheral surface of the residual covering portion 11 close to the cut surface 14 are adhered by the adhesive 7. In actual use, the other end face 17 of the ferrule 5 and the tip face 1 of the exposed core 13
8 is polished so as to form a smooth flush plane perpendicular to the axis of the exposed core 13.

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

[0006]

By the way, in the optical fiber connected to the fixed chip by the above-mentioned conventional method, while the optical fiber is used as a subsequent process or product, as shown in FIGS. In some cases, peeling may occur on the bonding surface 15 of the ferrule 5 or the bonding surface 20 of the grooved carrier 6 to form a peeled portion 8. 23 may be broken.

If the peeling portion 8 occurs even without such breakage, the fixed chip and the optical fiber may be suddenly bent at that portion, and precise and stable optical connection becomes difficult. Also, the ferrule 5 or the grooved carrier 6 and the exposed core are
Precise and stable due to the fact that the tip surface no longer becomes the same plane, the core of the optical fiber rotates from the original state inside the ferrule 5 or groove, and the deviation fluctuates due to temperature change. Optical connection sometimes becomes difficult.

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 peeled off. In this manner, the peeled portion 8 is generated, and the core portion 23 is formed at that portion.
In pursuit of the cause of the fracture, various experiments and studies have revealed that it is based on the following reasons. That is, when the removal coating portion 10 is pulled out in FIG. 2C, the remaining coating layer 9 that has not been cut by the blade 3 is torn off. Therefore, the remaining coating portion 11 is pulled and extended, and FIG.
The extension 4 is formed as shown in FIG. The length of the extension portion 4 depends on the strength of the coating layer 9 left by the blade 3. The adhesion to the ferrule 5 and the grooved carrier 6 was made in a state where the extension portion 4 was present. For this reason, the stress accumulated near the extension 4 of the residual coating 11 is released by heating in a subsequent step or heating provided during use as a product, and the residual coating 11 is returned to its original state (extension portion). (The length of 4 is 0). If the contraction force is greater than the adhesion force at the bonding surfaces 15 and 20, peeling will occur, and in some cases, the core 23 will break.

An object of the present invention is to reduce the contractive stress in the vicinity of the extension portion 4 of the residual coating portion 11 remaining after the removal coating portion 10 of the optical fiber is removed before the bonding between the optical fiber and the fixed chip. It is another object of the present invention to provide a method of connecting an optical fiber to a fixing chip with improved stability and reliability of the bonded portion. A second object of the present invention is to provide a first embodiment.
Another object of the present invention is to provide a connection method for further stabilizing the connection method of the optical fiber to the fixing chip according to the invention.

[0010]

In the invention of claim 1 [SUMMARY OF], covering the connection end of the optical fiber is removed, the stress of the residual coating of the optical fiber is reduced by a heating process, the core and remaining after which the optical fiber The end of the coating is glued to the fixing tip with an adhesive. According to the second aspect of the present invention, the heating step in the first aspect is performed so that the temperature of the core of the optical fiber, its coating and the adhesive is not higher than the maximum heat resistance temperature, and is higher than the maximum use temperature of the fixing chip to which the optical fiber is connected. Dripping.

[0011]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a method for connecting an optical fiber and a fixed chip according to the first and second aspects of the present invention. Parts corresponding to those of the conventional connection method shown in FIG. 2 are denoted by the same reference numerals.
1A, 1B, 1C, and 1D are FIGS. 2A, 2B, 2C, and 2D, respectively.
, And are exactly the same processing steps, and will not be described again here.

[0012] Figure 1D shows a state in which coating of the connecting end of the optical fiber (removing the coating unit 1 0) has been removed, a residual coating portion 11
The contraction stress is left in the vicinity of the extension part 4 of the above. In the present invention, the heating process is performed on the optical fiber in the residual covering portion 11 in this state. As a result, as shown in FIG.
The contraction stress in 1 is relaxed, that is, the length of the extension portion 4 becomes almost 0, and a stable state is obtained.

In one example shown in FIG. 1F, the extension 4
In a stable state in which the length of the optical fiber
Is inserted into the ferrule 5, and the outer peripheral edge 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 and the cut surface 14 of the residual covering portion 11 and the outer peripheral surface of the residual covering portion 11 close to the cut surface 14 are adhered by 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 in which the length of the extension portion 4 is almost 0, and The peripheral portion and the inner wall surface of the groove 19 are bonded with the adhesive 7. Also, one end surface 20 of the grooved carrier 6 and the cut surface 1 of the residual covering portion 11
4 and the outer peripheral surface of the residual covering portion 11 near the cut surface 14 are bonded with the adhesive 7.

In the embodiment of the method for connecting an optical fiber and a fixed chip according to the second aspect of the present invention, in the embodiment of the first aspect of the present invention, the heating step performed in the process of shifting from FIG. 1D to FIG. The temperature is lower than the maximum heat-resistant temperature of the optical fiber core 1, its coating 2, and the adhesive 7, and is higher than the maximum use temperature of the fixing chip 5 or 6 to which the optical fiber is connected.

[0016]

As described above, according to the method for connecting an optical fiber to a fixed chip according to the first aspect of the present invention, after the coating on the connection end of the optical fiber is removed, the remaining coating is removed by a heating step. After the stress is relieved ,
Since the core and the end of the residual coating are bonded to the fixing chip, the stability and reliability of the bonded portion are improved.

According to a second aspect of the present invention, in the heating step in the first aspect, the heating temperature of the core of the optical fiber, its coating and the adhesive is not higher than the maximum temperature, and the maximum operating temperature of the fixing chip to which the optical fiber is connected. Since the above is maintained, the stability and reliability of the bonded portion are further improved.

[Brief description of the drawings]

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

FIGS. 2A and 2B show each step of a conventional connection method of an optical fiber to a fixed chip and a state after that, where A is a view showing the optical fiber before processing, and B is a state where a cut is made in a coating portion with a blade. FIG. 1C shows a state in which the coating on both sides of the cut is tensioned and pulled, FIG. 2D shows a state in which the coating on the connection end of the optical fiber has been removed, and FIG. 2E shows a ferrule between the optical fiber and the optical fiber connector. F is a diagram showing the state of peeling of the bonded portion after the lapse of time of connection between the optical fiber and the ferrule of the optical fiber connector, G is a connection diagram of the optical fiber and the grooved carrier, H
FIG. 4 is a view showing a state of peeling of an adhesive portion after a lapse of time of connection between the optical fiber and the grooved carrier.

Claims (2)

(57) [Claims] 1. A removal of the coating of the connecting end of the optical fiber, to relax the stress of the residual coating of the optical fiber by the heating step, adhesive fixing tip ends of the core and the residual coating of the optical fiber A method for connecting an optical fiber to a fixing chip, characterized in that the optical fiber is bonded by a bonding method. 2. The heating step is performed at a temperature not higher than the maximum heat resistance of the core of the optical fiber, its coating and the adhesive, and at a temperature equal to or higher than the maximum use temperature of the fixing chip to which the optical fiber is connected. A method for connecting an optical fiber according to claim 1 to a fixing chip.