JPH10123349A - Method and device for connecting optical fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the method and device for optical fiber connection which make it possible to precisely set a pressing force along an optical axis and are not affected by thermal expansion due to temperature variation and small in variation in connection loss. SOLUTION: Both optical fibers 1 and 2 to be connected have their rear fixed while held so that they can be made to abut against each other by an optical axis aligning component 4, and in this state, the optical axis aligning component 4 is moved and fixed where at least one of the optical fibers 1 and 2 has a bent part 1' or 2' formed, thereby operating a pressing force on the abutting end surfaces of both the optical fibers 1 and 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber connecting method and apparatus.

[0002]

2. Description of the Related Art Conventionally, optical fibers are connected by a method in which end faces of both optical fibers are connected to each other in a capillary sleeve or on a V-groove.
In this case, a refractive index matching agent is used in the gap to fill the gap between the end faces of the optical fibers on both sides to be connected to reduce the connection loss and to prevent the reflection of the optical signal between the end faces.

However, in the above connection method, the butt and close state of the two optical fibers is insufficient, so that the optical fiber main body having a low coefficient of thermal expansion and the resin optical fiber covering material having a high coefficient of thermal expansion are not covered. Due to the difference in the coefficient of thermal expansion between the components of other optical fiber connection equipment or the temperature change in the environment where the optical fiber cable is laid, the butted end faces of both optical fibers are separated from each other, and the connection loss increases significantly. There is. Further, since the refractive index matching agent has a temperature dependency, the refractive index changes due to a temperature change, and there is a problem that an amount of reflection of an optical signal at an end face of the optical fiber increases.

Therefore, recently, the end faces of both optical fibers are brought into contact with each other in a sleeve fixed on a base component, and thereafter, a pressing force is applied in the optical axis direction from the rear side, so that the end faces of the two optical fibers are interposed. A connection method has been proposed in which a pressing force in the direction of the optical axis is generated, and in this state, the rear portions of both optical fibers are held and fixed to a base component.

[0005]

However, in the above proposed method, a pressing force is applied in the direction of the optical axis from behind the two optical fibers to generate a pressing force in the direction of the optical axis on the butted end faces of the two optical fibers. Therefore, the pressing force from the rear becomes the pressing force in the optical axis direction as it is, and it is difficult to accurately set the pressing force in the optical axis direction at the optical fiber connection site. For example, if the pressing force in the direction of the optical axis is excessive, breakage of the optical fiber or loss or damage of the end face of the butt occurs, and if the pressing force in the direction of the optical axis is too small, a change in the gap causes a connection loss. There are increasing disadvantages.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and an apparatus for connecting an optical fiber in which the pressing force in the direction of the optical axis can be accurately set, is not affected by thermal expansion due to a temperature change, and has little variation in connection loss. Is to do.

[0007]

In order to achieve the above object, a method of the present invention is to maintain both connected optical fibers in a state where they can be butted by an optical axis aligning part, and to set the rear of each of the optical fibers. Fixing, and then moving the optical axis alignment component in this state and fixing it at a position where a bent portion is formed in at least one optical fiber, thereby applying a pressing force to the butted end surfaces of both optical fibers. It is assumed that.

According to the above-mentioned structure, the present invention provides an optical axis aligning component in which the end faces of both optical fibers are butted against each other, the rear of both optical fibers is fixed in this state, and then the optical axis aligning component is moved. It is not necessary to adjust and set the pressing force from the rear of the optical fiber to an accurate predetermined value as in the related art. Therefore, the pressing force in the optical axis direction is
It can be set accurately with the movement amount of the optical axis alignment component. Also, the difference in the thermal expansion coefficient between the members and the variation in the pressing force in the optical axis direction due to the temperature change can be absorbed by the bent portion of the optical fiber, and is not affected by the thermal expansion due to the temperature change. A small number of optical fiber connectors can be provided.

Further, the method of the present invention is particularly preferably applied to a case in which the optical fiber is preliminarily processed so that the core portion of the optical fiber protrudes from the cladding portion. In this case, it is possible to reduce the reflection of the optical signal at the butt end face without using the refractive index matching agent, and to reduce the connection loss without being affected by the temperature change.

Further, the apparatus according to the present invention comprises an optical axis aligning component for holding the two optical fibers to be connected in a state where they can be butted in the optical axis direction, and a support for movably supporting the optical axis aligning component at the center of the upper surface. A base part having a member, and a fixing part for fixing the two optical fibers to each side via a bending formation space of the optical fiber on a side of the member; and a position where the bending part is formed on the optical fiber by aligning the optical axis alignment part with the optical fiber. And a holding part for holding and fixing the moved optical axis alignment part to the base part.

With the above arrangement, the apparatus of the present invention can be used directly for carrying out the above method, and the pressing force of the optical fiber in the optical axis direction can be set accurately by the movement amount of the optical axis alignment component. . Also, the difference in the thermal expansion coefficient between the members and the variation in the pressing force in the optical axis direction due to the temperature change can be absorbed by the bent portion of the optical fiber, and is not affected by the thermal expansion due to the temperature change. An optical fiber connector with less fluctuation can be provided.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to carry out the method of the present invention, first, as shown in FIG. 1 (A), two optical fibers 1 and 2 to be connected are prepared. To do this, both optical fibers 1, 2
The coatings 1a and 2a of the connection side end portions are peeled and removed by a predetermined dimension,
Cut the end face precisely (use a suitable optical fiber cutting tool such as a commercial product). PC (Physical Contact)
When the connection is made, after the end surface is cut, a process of projecting the core portion from the clad portion, such as chamfering of the end surface, chemical etching, or spherical polishing of the end portion (see FIG. 3), is performed. In FIG. 3, reference numerals 1b and 2b denote optical fiber cores, and reference numerals 1c and 2c denote cladding portions. The PC connection is performed by using a pure physical action without using a refractive index matching agent. This is a method for connecting the optical fibers 1 and 2, specifically, the core 1 of the two optical fibers 1 and 2.
b and 2b are connected by applying a pressing force in the optical axis direction to the butted end faces.

Next, as shown in FIG. 1B, the insertion hole 4a of the sleeve 4 illustrated as an optical axis alignment component temporarily held on the base component 3 is prepared as shown in FIG. The end of one of the optical fibers 1 is inserted from one side (left side) of the sleeve 4 to substantially the center thereof, and the rear part of the optical fiber 1, for example, the coating 1 a is placed on the base component 3 by the fixing component 5. Fix it. Subsequently, the end of the other optical fiber 2 is inserted into the insertion hole 4a of the sleeve 4 from the other side (right side) and abuts against the end face of the optical fiber 1 inserted earlier. For example, as shown in FIG.
To fix on the base component 3. The insertion hole 4a of the sleeve 4 has an inner diameter slightly larger than the diameter of the optical fibers 1 and 2, and both ends of the insertion hole 4a are tapered to facilitate insertion of the optical fibers 1 and 2. Have been. As the sleeve 4, a capillary tube made of glass, metal, resin, or the like is used.

Finally, as shown in FIG. 1D, the sleeve 4 is moved in a direction intersecting the optical axis to generate a pressing force in the optical axis direction on the butted end faces of the two optical fibers 1 and 2. The connection is terminated while maintaining this state. In order to generate the pressing force in the optical axis direction, both optical fibers 1 and 2
Of the optical fibers 1 and 2 by the abutting ends and the fixing parts 5 and 6, that is, the coatings 1a and 2a.
A curved flexure 1 ', 2' is formed between the part and its fixed position on the base part 3. After the connection, this state is maintained.

FIG. 2A is a plan view showing an embodiment of the optical fiber connecting device of the present invention, FIG. 2B is a sectional view taken along the line BB of FIG. 2A, and FIG. (B) is a sectional view similar to the figure, wherein 1 and 2 are optical fibers, 3 is a base component, 4 is a sleeve exemplified as an optical axis alignment component, 5,
Reference numeral 6 denotes an optical fiber fixing component, 7 denotes a moving unit of the optical axis aligning component, and 8 denotes a holding component that holds and fixes the optical axis aligning component after being moved by the moving unit.

In the case of the present embodiment, the base component 3 is a supporting member for supporting a sleeve 4 exemplified as an optical axis aligning component at the center of the upper surface so as to be movable in a direction intersecting the optical axis (in FIG. 2, the vertical direction is exemplified). 3a, the rear portions of the two optical fibers 1 and 2, for example, the coatings 1a and 2a, are fixed on the base component 3 via the bending formation spaces 3b and 3c of the two optical fibers 1 and 2 on both sides thereof. It has fixing parts 3d and 3e. The upper surface of the support member 3a of the base component 3 has a V-groove shape, and the sleeve 4 is fixed on the V-groove by an adhesive or the like. In order to facilitate the insertion of the optical fibers 1 and 2 into the sleeve 4, the V-groove guides 3h, 3h
i are provided on both sides of the sleeve 4.

The optical fiber fixing parts 5, 6 corresponding to the fixing parts 3d, 3e of the base part 3 can approach and separate from the fixing parts 3d, 3e via wedge members 5a, 6a having inclined upper surfaces. It is installed in. In addition, on the lower surfaces of the optical fiber fixing parts 5 and 6, inclined surfaces corresponding to the inclined surfaces of the wedge members 5a and 6a are formed. Fixed part 3 of base component 3
d and 3e are formed with grooves or holes 3f and 3g for inserting and holding the rear portions of the optical fibers 1 and 2, for example, the coatings 1a and 2a. On the insertion end side, the optical fibers 1 and 2 are tapered to facilitate insertion.

The moving means 7 of the optical axis aligning component is for moving the sleeve 4 exemplified as the optical axis aligning component in the direction intersecting the optical axis via the support member 3a. A wedge member 7a having an upper surface inclined is movably mounted on the base component 3 corresponding to the lower surface of the support member 3a. An inclined surface corresponding to the inclined surface of the wedge member 7a is formed on the lower surface of the support member 3a. The wedge member 7a can be moved by a driver tool or the like having a minus tip from a window hole 3j formed on the lower surface of the base component 3.

The holding component 8 for holding and fixing the optical axis alignment component after being moved by the optical axis alignment component moving means 7 is illustrated as being fixedly arranged on the base component 3.

When the optical fibers 1 and 2 are connected by the apparatus of this embodiment, the coatings 1a and 2a of the ends to be connected are peeled off by a predetermined size in the manner described with reference to FIG.
Make a precision cut of the end face. Further, in the case of the PC connection, the end face of the optical fiber is selectively etched by chamfering the precision cut end face and chemically etching (using an acidic ammonium fluoride solution or the like to selectively erode the clad portions 1c and 2c of the end face of the optical fiber.
b, 2b) or spherical polishing of the end face (see FIG. 3).

Then, the tip of one optical fiber 1 is inserted from the left side into a groove or hole-like insertion hole 3f between the fixing portion 3d on the left side of the base component 3 and the optical fiber fixing component 5, for example. At this time, the wedge members 5a, 6a are drawn out to both sides in advance, and the optical fiber fixing parts 5, 6 are separated from the fixing parts 3d, 3e of the base part 3. Left optical fiber 1
Is inserted to a substantially central portion in the sleeve 4, and the left wedge member 5a is pushed toward the center of the base component 3 to move the optical fiber fixing component 5 to push the optical fiber 1 against the fixing portion 3d. Fix it. The support member 3a of the sleeve 4 is set at a lower position in advance.

Next, the tip of the right optical fiber 2 is inserted from the left into a groove or hole-shaped insertion hole 3g between the right fixing portion 3e of the base component 3 and the optical fiber fixing component 6, and the light is further transmitted. The distal end of the fiber 2 is inserted until it hits the distal end of the left optical fiber 1 which has been inserted into the end of the sleeve 4. Then, in this state, the right wedge member 6a is pushed toward the center of the base component 3 and moved to raise the right optical fiber fixing component 6, and the optical fiber 2 is fixed to the fixing portion 3e.
Press to fix.

Finally, the sleeve 4 is moved in a direction intersecting the optical axis. More specifically, as shown in FIGS. 2B to 2C, the wedge member 7a of the moving means 7 is moved to the left, and the support member 3a of the base component 3 is pushed up and held by the inclined surface at the tip. The sleeve 4 is pressed against the component 8 and fixed and held in this state. The fixed holding in this state is performed by the moving means 7.
The wedge member 7a is fixed to the base component 3 while the lower surface of the support member 3a is supported by the inclined surface at the tip of the wedge member 7a,
Alternatively, this is achieved by supporting the lower surface of the support member 3a with a flat upper surface following the inclined surface of the tip of the wedge member 7a of the moving means 7.

As described above, the tips of the two optical fibers 1 and 2 are inserted into the sleeve 4, and the rear portions of the two optical fibers 1 and 2, for example, the coating portions 1 a and 2 a are fixed on the base component 3. Thus, the two optical fibers 1 and 2 are
In this state, the sleeve 4 is moved in a direction intersecting the optical axis by the moving means 7 so that the two optical fibers 1 and 2 can be bent in the space 3b of the base component 3. The optical fibers 1 and 2 are bent at positions 3c to form bent portions 1 'and 2', and a pressing force in the optical axis direction can be generated on the butted end faces of the optical fibers 1 and 2.

The pressing force in the optical axis direction generated on the butted end faces of the two optical fibers 1 and 2 is determined by the amount by which the sleeve 4 is moved in a direction intersecting the optical axis, and in the embodiment of the present invention. , Can be accurately set by the size of the gap between the holding member 8 and the sleeve 4 or the height of the inclined surface at the tip of the wedge member 7a of the moving means 7.

Although the wedge member 7a is exemplified as the moving means 7 in the above-described embodiment, the moving means 7 is not limited to the wedge member 7a. Can be adopted.

As means for fixing the rear of the optical fibers 1 and 2 on the base component 3, one or both of the optical fibers 1 and 2 are preliminarily fixed at another place.
After fixing the end of the optical fiber in the optical axis aligning component, it may be fixed to the fixing portions 3d, 3e of the base component 3, or it may be fixed with an adhesive. . However, if the fixed parts 5 and 6 are made movable by the wedge members 5a and 6a as in the present embodiment, one or both of the optical fibers 1 and 2 are exchanged for maintenance inspection and repair of the optical fiber line. In such a case, the connection device can be used repeatedly as it is. In particular, when a PC connection that does not use a refractive index matching agent is employed, the configuration of the present embodiment is preferable.

Although this embodiment exemplifies a single-core (one optical fiber) type connection device having the simplest configuration, the present invention is also applied to a multi-core type (multiple optical fibers) connection device. be able to. For example, when used to connect tape-shaped optical fibers having the same number of cores, the part holding the optical fiber of the optical axis alignment component should be one that matches the number of cores and the pitch of the tape-shaped optical fiber, and the optical fiber fixing component What is necessary is just to make 5 and 6 correspond to the dimension shape of a tape. Further, when connecting optical fibers of independent cables to each other, a plurality of support members 3a, a plurality of optical fiber fixing parts 5, 6, and wedge members 5a, 6a are arranged in parallel with a plurality of sleeves 4, In addition, it is only necessary to dispose the moving means 7 to move the sleeves 4 individually and independently in a direction intersecting the optical axis.

Further, in either case of the single-core type or the multi-core type, the present invention can be applied to a case where one is connected to the bus side of an optical fiber cable and the other is connected to desired equipment of each home or customer. In this case, the bus line side fixes the optical fiber permanently or semi-permanently, and the connection side to the desired equipment of each home or customer can attach and detach the optical fiber. It is preferable to adopt a configuration similar to that of the second embodiment.

The base part 3, the optical fiber fixing parts 5, 6, the moving means 7, and the holding part 8 are made of resin, metal,
Alternatively, the base part 3 may be divided and formed at an appropriate position from the viewpoint of molding or assembling moving parts, and the base part 3 may be fastened by fastening means such as bolts. It is preferable to assemble them. The holding component 8 is detachably attached to the base component 3 with a bolt or the like, or can be opened and closed by a hinge structure. The holding component 8 may be removed from the base component 3 when the optical fiber is inserted into the sleeve 4 and may be fixed on the base component 3 after the insertion of the optical fiber, or may be made of a transparent resin or the like. By configuring, when inserting the optical fiber into the sleeve 4, the insertion state may be made visible.

Although the above embodiment has exemplified the case where the sleeve 4 is pushed down or pushed up and down, the present invention may be arranged such that the sleeve 4 is moved horizontally in the horizontal direction. It may be rotated about the center. Further, in the above-described embodiment, the case where the bending is formed in both of the optical fibers to be connected is illustrated. However, the bending may be formed in only one of the optical fibers (for example, the side opposite to the bus). . In the case where only one of the flexures is formed, for example, the sleeve 4 is initially held in an inclined state at a certain position at the end on the busbar side, and the optical fiber is inserted into the sleeve 4 from the side opposite to the busbar. Only the side opposite to the generatrix is moved by the moving means 7 so as to be in a horizontal state, to bend, and to generate a pressing force in the optical axis direction on the butted end face of the optical fiber.

The optical axis aligning component used in the present invention is not limited to a sleeve, but uses a gap between three rods, holds a V-groove and its holding lid, etc. so that an optical fiber can be abutted in the optical axis direction. Anything that can be done is acceptable.

In the present invention, the phrase “the core portion of the optical fiber end face is processed so as to protrude from the clad portion” means that the clad portion may partially remain on the same surface as the core portion, It is sufficient that the core portions of both optical fibers are in close contact with each other when the pressing force in the direction is applied.

[0034]

According to the optical fiber connecting method and apparatus of the present invention, since a pressing force in the optical axis direction is generated at the butting end faces of the optical fibers on both sides, the connecting end faces of the optical fibers due to the temperature change. It is possible to prevent the generation of a gap between them. In addition, it is possible to provide a margin for the tensile force of the optical fiber from the outside until a gap is generated between the connection end faces of the optical fiber. In addition, a Pp without using a refractive index matching agent between the butted end faces of the optical fibers on both sides.
When the C connection method is adopted, a pressing force in the optical axis direction can always be applied to the butted end faces of the optical fibers, so that separation of the end faces due to a temperature change can be prevented, and an optical fiber connection with little variation in connection loss can be prevented. Can be provided and re-use is easy.

[Brief description of the drawings]

1 (A) to 1 (D) are views for explaining an operation sequence of an optical fiber connection method according to the present invention.

2A is a schematic perspective view showing an embodiment of the optical fiber connecting device of the present invention, FIG. 2B is a sectional view taken along the line BB in FIG. 2A, and FIG. Sectional drawing in the same position as FIG.

FIG. 3 is an explanatory view schematically showing a main part of a PC connection method.

[Explanation of symbols]

 1, 2 optical fiber 1a, 2a coating of optical fiber 3 base component 4 optical axis alignment component (sleeve) 5, 6 optical fiber fixing component 7 moving means 8 optical axis alignment component fixing component

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshimasa Yamaguchi 2-7-1 Hararashi, Otsu City, Shiga Prefecture Nippon Electric Glass Co., Ltd.

Claims (3)

[Claims] 1. An optical axis aligning component holds both connected optical fibers in a state where they can be butted with each other, and fixes the rear of each optical fiber. A method for connecting optical fibers, characterized in that a pressing force is applied to the butted end surfaces of both optical fibers by fixing the optical fibers at a position where a bent portion is formed. 2. The optical fiber connecting method according to claim 1, wherein the butted end surface of the optical fiber is processed in advance so that a core portion thereof protrudes from a clad portion. 3. An optical axis aligning component for holding both connected optical fibers in a state where they can be butted in the optical axis direction, and a support member at the center of the upper surface for movably supporting the optical axis aligning component. A base component having a fixing portion for fixing the two optical fibers via the optical fiber bending formation space to the side of the optical fiber, and moving means for moving the optical axis alignment component to a position where the bending portion is formed in the optical fiber. And a holding component for holding and fixing the moved optical axis alignment component to the base component.