JPH10274721A - Method of connecting optical fibers, optical fiber connector, and method of grinding optical fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve an optical fiber coupling with a simple and small structure, a low reflection and a low loss. SOLUTION: An end face of a naked optical fiber 1 of an optical coated fiber 3 is made as a slope 2 tilted to an optic axis, and two slopes 2 are abutted against each other so as to be in parallel in a hole of a hollow member 6 fixed on a substrate 4 with an adhesive 7, etc. And, the two optical fibers 1 are bent or one of the optical fibers 1 is bent and are fixed at their heels on the substrate 4 by fixing members 5, 5A.

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, an optical fiber connector, and an optical fiber polishing method.

[0002]

2. Description of the Related Art FIG. 5 shows a first conventional example, and FIG.
The following shows a conventional example.

In the first conventional example, as shown in FIG. 5A, a ferrule 24 is used for reinforcing an optical fiber, and the optical fiber 1 of the optical fiber core 3 is inserted into a through hole at the center of the ferrule 24. The end face of the optical fiber 1 is polished together with the ferrule 24 into a slope. Reference numeral 25 indicates an obliquely polished surface. As shown in FIG. 5B, the two ferrules 24 to which the optical fiber 1 is fixed abut each other with the slopes parallel in a sleeve 26, and from the respective rear ends by the spring members (not shown) by arrows 27 and 28. To ensure the connection.

In the first conventional example, even if the light is reflected on the inclined surface, the rate of recombination with the core of the optical fiber 1 is reduced, so that a low-reflection optical fiber connection is realized. For example, when the slope has a slope of 8 degrees, a return loss of 70 dB or more can be realized. Splice loss is inferior to vertical polished end face,
By increasing the manufacturing accuracy of the ferrule 24 and the sleeve 26, even when a single mode optical fiber in a long wavelength band for communication is used, it can be suppressed to 0.5 dB or less. An optical fiber connector is realized by adding a latch mechanism or the like to this connection form.

Next, in the second conventional example, as shown in FIG. 6 (b), two optical fibers 1 whose end faces are vertically cleaved or polished are cut into holes each slightly larger than the optical fiber outer diameter. The optical fibers 1 are bent at their rear ends as shown in FIG. 6A, and are fixed to the substrate 4 by the fixing members 5 and 5A. At this time, the end faces of the optical fiber 1 come into close contact with each other due to the elastic restoring force of the bent portion,
An optical fiber connection is realized. This elastic restoring force can be controlled by the length of the bent portion. For glass optical fiber,
The elastic restoring force is about 70 g when the length of the bent portion is 7 mm.
With such an elastic force, the end faces of the optical fiber 1 sufficiently adhere to each other. The hollow member 6 is fixed on the substrate 4 with an adhesive 7.

In the second conventional example, when an optical fiber 1 having an outer diameter of 125 μm is connected in a hollow member 6 having an inner diameter of 126 μm, a connection loss of 0.3 dB is obtained when a single mode optical fiber in a long wavelength band for communication is used. The following is realized. The return loss is about 60 dB when the end face is a cleavage plane. When the end face is a polished surface, a polishing layer having a different refractive index is formed on the surface, so that the return loss slightly deteriorates to about 55 dB. According to the second conventional example, since the ferrule 24 and the spring member are not used unlike the first conventional example, a small optical fiber connector can be realized.

[0007]

However, in the first conventional example, it is necessary to process the outer diameter of the ferrule 24 and the inner diameter and center position of the optical fiber through-hole thereof with high precision. In addition, it is necessary to grind the inclined surface at a high precision. Further, a spring member is required. From the above, the cost was high and miniaturization was difficult.

On the other hand, in the second conventional example, although it is possible to reduce the size, it is difficult to achieve a return loss of 60 dB or more, and when it is open, all reflections from air become return light. I will. Therefore, there is a problem that the reflection becomes large even if there is small dust.

Accordingly, the present invention provides an optical fiber connection method, an optical fiber connector, and an optical fiber polishing method capable of realizing an optical fiber connector having a simple structure and stable and low reflection and low connection loss characteristics. The task is to

[0010]

According to a first aspect of the present invention, there is provided an optical fiber connecting method, wherein the end faces of the two optical fibers are inclined, and the end faces of the two optical fibers are connected to each other. Abutment is performed in a hole having an inner diameter slightly larger than the outer diameter of the optical fiber, and at least one optical fiber is bent and fixed at the rear end.

According to a second aspect of the present invention, in the optical fiber connecting method, at least one of the end faces of the two optical fibers is chamfered.

Further, in the invention according to claim 3, in the single-core or multi-core optical fiber connector, the tips of the optical fibers obliquely inclined with respect to the optical axis are parallel to each other, and the outer diameter of the optical fiber is smaller than the outer diameter of the optical fiber. The optical fiber at the rear end is bent and abutted in a hole having a slightly larger inner diameter.

In the optical fiber connector for a tape optical fiber according to the fourth aspect of the present invention, an optical fiber having each end face inclined obliquely with respect to the optical axis is attached, and the direction of each inclined face is set in the tape optical fiber. Are aligned with one direction of the alignment direction of the optical fibers, and the tips of the respective optical fibers are mounted so that the slopes of the respective optical fibers are parallel to each other and have an inner diameter slightly larger than the outer diameter of the optical fibers. An optical fiber connector, wherein an optical fiber at a rear end is bent and abutted in the hole.

According to a fifth aspect of the present invention, in the method for polishing an optical fiber end face, the optical fiber is gripped at a position of a certain length from the end face, and the distance between the grip portion and the polishing member is set to be equal to or less than this length. The gripper and the polishing member are relatively linearly moved.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 shows a first embodiment (optical fiber connection method), FIG. 2 shows a second embodiment (optical fiber connection method), FIG. 3 shows a third embodiment (optical fiber connector), FIG. 4 shows a fourth embodiment (optical fiber polishing method).

(First Embodiment) An embodiment of an optical fiber connection method according to the first aspect of the present invention will be described as a first embodiment with reference to FIG. In the present embodiment, the end face of the bare optical fiber 1 of the optical fiber core 3 is a slope 2 obliquely inclined with respect to the optical axis as shown in FIG. As shown in FIG. 1C, two optical fibers 1 each having such an end face formed on a slope are used to form two slopes 2 in a hole of a hollow member 6.
The two optical fibers 1 are butted so that they are parallel to each other, and the two optical fibers 1 are bent as shown in FIG.
As shown in (b), one of the optical fibers 1 is bent and fixed on the substrate 4 by the fixing member 5 at the rear end thereof. At this time, even if the directions of the slopes 2 of the two optical fibers 1 are slightly shifted and are not initially parallel, the optical fibers 1 are twisted by themselves and come into contact with each other.

The hollow member 6 has a hole having an inner diameter slightly larger than the outer diameter of the optical fiber 1, and is shown in FIG.
As shown in (b), it is fixed on the substrate 4 with an adhesive 7 or the like. In the hole of the hollow member 6, tapered portions are formed at the inlets on both sides for alignment as required. The fixing member 5A is for fixing the optical fiber core 3 on the substrate 4, and according to the difference between the outer diameters of the optical fiber core 3 and the optical fiber 1, the installation site of the fixing member 5A is that of the fixing member 5. Has been lower than.

In the optical fiber connecting method of this embodiment, since the end face of the optical fiber is the slope 2, the end faces are strongly adhered to each other to suppress reflection as in the case of the right-angled end face of the second conventional example (FIG. 6). It is not necessary to make the optical fiber 1 bent.
This is effective for absorbing the displacement of the abutting positions of each other. Accordingly, the length of the bent portion can be increased in order to suppress bending loss and allow a margin for bending failure.

When the optical fiber 1 is gripped by the fixing member 5 for a short time, as shown in FIG.
Bends. Also, if the optical fiber 1 is gripped by the fixing member 5 with substantially the same length, the two members are balanced by the friction between the hollow member 6 and the optical fiber 1 as shown in FIG. Bend. In the former case (FIG. 1 (b)), since the optical fiber 1 is bent at one point, the bending loss is suppressed and the margin for bending breakage is further increased. The latter (Fig. 1 (a))
Then, when a connector is formed, the versatility is improved because the connector is the same on both sides.

In this embodiment, a single-mode optical fiber having an outer diameter of 125 μm and a long wavelength band for communication is polished to an inclination of 8 degrees (θ = 8 degrees in FIG.
When they are connected to each other in the 6 μm hollow member 6, an optical fiber connection having optical characteristics of about 70 dB in return loss and about 0.4 dB in connection loss can be realized with a simple structure.

(Second Embodiment) Next, an embodiment of an optical fiber connection method according to the second aspect of the present invention will be described as a second embodiment with reference to FIG. In this embodiment, FIG.
In addition to the connection structure of the first embodiment shown in FIG.
As shown in (a), (b) and (c), a chamfered portion 8 is formed on the slope 2 of the end face of the two optical fibers.

That is, two bare optical fibers 1 each having a chamfered portion 8 formed by cutting the corner of the edge on the slope 2 at the tip end are used.
As shown in FIG. 2 (c), two slopes 2 are joined so as to be parallel in the hole of the hollow member 6, and the two optical fibers 1 are bent as shown in FIG. 2
As shown in (b), one of the optical fibers 1 is bent and fixed on the substrate 4 by the fixing member 5 at the rear end thereof.
The optical fiber core 3 is fixed on the substrate 4 by a fixing member 5A. The hollow member 6 has a hole having an inner diameter slightly larger than the outer diameter of the optical fiber 1.

In the present embodiment, since the area of the connection surface (slope) is reduced by the chamfered portion 8, the gap immediately before the elastic restoring force of the optical fiber 1 is applied to the unevenness of the surface not less than a little on the slope 2. Is smaller than that of the first embodiment in which chamfering is not performed. Thus slope 2
Since the gap between them is small, a lower loss optical fiber connection can be realized, and a connection loss of 0.2 dB or less can be realized.

Further, as an effect of the chamfered portion 8, since it is easy to insert into the alignment hole, the diameter of the tapered portion to be provided at the entrance on both sides of the hole of the hollow member 6 can be reduced. In particular, when connecting tape optical fibers in which a plurality of optical fibers are arrayed, the outer diameter of the hollow member 6 can be reduced by reducing the diameter of the hole tapered portion of the hollow member 6. The spacing between the fibers can be made as small as possible, and an optical fiber connector with an improved mounting density can be realized as shown in FIG.

In the optical fiber connection example shown in FIG.
The outer diameter of the hollow member 6 and the tapered portion at the hole entrance are both reduced in diameter, and the same number of hollow members 6 as the number of optical fibers in the tape optical fiber 9 are placed on the substrate 4 at the same or less than the optical fiber alignment interval. The two bare optical fibers 1 each having a chamfered portion formed at the tip of the hollow member 6 are abutted in each hole so that the two slopes are parallel to each other, and the optical fiber 1 is bent. Instead, it is fixed to the substrate 4 by a fixing member 5 at the rear end. Needless to say, even when the chamfered portion is not formed on the tip slope as in the first embodiment, the optical fibers in the two tape optical fibers 9 can be connected by arranging a plurality of hollow members.

Although the two optical fibers 1 are connected to each other in each of the optical fiber connecting methods of the first and second embodiments, the application of these optical fiber connecting methods is performed by using an optical waveguide on one side. There may be. In this case, the end face of the optical waveguide is inclined, and the hollow member is mounted on the end face of the optical waveguide so that the center thereof coincides with the core of the optical waveguide, and an optical fiber having a beveled tip is inserted into the hollow member. It is realized by. Of course, the inclined end faces of the optical waveguide and the optical fiber may be chamfered. Regardless of the connection between the optical fibers 1 and the connection between the optical fiber and the optical waveguide, if the chamfered portion is formed on at least one of the two inclined surfaces that abut each other, the gap between the inclined surfaces is reduced, so that lower loss is achieved. The operation and effect of realizing a simple optical fiber connection can be achieved.

(Third Embodiment) Next, an optical fiber connector according to a fourth embodiment of the present invention will be described as a third embodiment with reference to FIG. In this embodiment, FIG.
As shown in (a), the connector plug 10 holds the tape optical fiber 9 attached thereto with an optical fiber holding portion 11 and fixes it via an adhesive 7. Then, FIG.
As shown in FIG. 2, by connecting two connector plugs 10 in opposition to each other via a connector adapter 12 having a tapered through hole 13, the ends of the bare optical fibers 1 are parallelized in each tapered through hole 13. Then, the rear ends are bent and abutted to connect multi-core optical fibers such as an optical fiber array or a tape optical fiber 9. The connector adapter 12 has a flat shape, and has a plurality of tapered through-holes 13 having an inner diameter slightly larger than the outer diameter of the optical fiber 1 formed in parallel inside.

At this time, the tip end surface of each optical fiber 1 in the tape optical fiber 9 is the inclined surface 2 which is obliquely inclined with respect to the optical axis, and the direction 14 of each inclined surface is one direction of the optical fiber alignment direction of the tape optical fiber 9. The directions are aligned with each other, and the tip positions of the optical fibers 1 are aligned.

Therefore, when two optical fiber connectors (connector plugs) are opposed to each other, the slopes 2 of the optical fibers 1 are always parallel to each other as shown in FIG. It becomes possible.

Further, in this embodiment, as shown in FIG. 3C, the slope 2 at the tip of each optical fiber 1 is chamfered so that the interval between the tapered through holes 13 of the connector adapter 12 can be made as small as possible. It is. Reference numeral 8 denotes a chamfer. Thereby, a smaller optical fiber connector with lower loss is realized.

Here, a specific example of the connector plug 10 will be described. The optical fiber gripping portion 11 of this embodiment grips the tape optical fiber 9 by passing each bare optical fiber 1 through a plurality of holes formed therein. The tape optical fiber 9 is fixed at the rear end with an adhesive 7.
Each hole of the optical fiber holding portion 11 is formed at the same interval as the optical fiber alignment interval of the tape optical fiber 9.

A passage 15 having a flat cross section is formed in the longitudinal direction of the connector plug 10, a notch 16 is formed at the tip of the passage 15, and a notch 17 is formed on the upper surface so as to communicate with the passage 15. It is. Passage 15 is tape optical fiber 9
A plurality of optical fibers 1 are collectively used to pass through, a notch 16 is used to receive a part of the connector adapter 12, and a notch 17 is used for the adhesive 7 and the optical fiber gripper 11. Used to fit. The optical fiber holding portion 11 may be formed integrally with the connector plug 10.

Next, a specific example of the connector adapter 12 will be described. Each of the tapered through holes 13 has the same optical fiber alignment interval as the interval between the optical fibers 1 gripped by the optical fiber gripper 11 and is parallel to each other. It is formed.

The connector adapters 12 are inserted into the cutouts 16 of the two connector plugs 10 and the two connector plugs 10 are connected. Then, two connector plugs 10
The rear end portions of the optical fiber 1 attached to the connector adapter 12 are abutted in parallel with each other in the through hole 13 of the connector adapter 12 in a state where the rear end portions are bent. At this time, as described above, since the slope direction 14 of the optical fiber 1 in the tape optical fiber 9 coincides with one direction of the alignment direction of the optical fiber, the slopes of the opposing optical fibers are always parallel and inverted upside down. The connection can be made without the connection. Further, since the chamfered portion 8 is provided on the inclined end surface 2 of each optical fiber 1, low-loss optical fiber connection can be realized. In addition, the interval between the tapered through holes 13 of the connector adapter 12 can be made equal to or less than the alignment interval of the optical fibers in the tape optical fiber 9, and the optical fiber connector can be downsized accordingly.

Although the optical fiber connector of this embodiment is suitable for an optical fiber array, one hole in the optical fiber gripper 11 and one through-hole 13 with a taper in the connector adapter 12 are provided.
If it is made into individual pieces, it becomes the single core optical fiber connector according to the invention of claim 3. In this case, the widths of the connector plug 10 and the connector adapter 12 are reduced as necessary. Also, the slope direction 1 of the optical fiber 1 in the tape optical fiber 9
Even if the optical fibers 4 do not coincide with one direction of the optical fiber alignment direction, even if the optical fibers 1 are twisted by themselves and the inclined surfaces 2 come into contact with each other and the tip positions of the optical fibers 1 are not aligned, The bent portion absorbs the displacement of the abutting position of the optical fibers 1 and the slopes 2 come into contact with each other, so that good connection is possible, and an arbitrary multi-core optical fiber connector according to the invention of claim 3 is obtained. .

In each of the first, second, and third embodiments, the means for forming the end face of the optical fiber 1 into the slope 2 and the means for forming the chamfer 8 on the slope 2 are basically arbitrary. Means are good.

(Fourth Embodiment) Next, an embodiment of an optical fiber polishing method according to the fifth aspect of the present invention will be described as a fourth embodiment with reference to FIG. In this embodiment, FIG.
As shown in (a), each optical fiber 1 in the tape optical fiber 9 is gripped by an optical fiber gripper 11 at a length L1 from the tip, and the gripper 11 is perpendicular to a polishing member such as a polishing plate 18. The distance between the holding portion 11 and the polishing plate 18 is made close to the length L2 (L2 <L1), and the optical fiber 1 is bent. In this state, for example, the gripper 11 is linearly moved in a direction 19 opposite to the direction of bending, or
The polishing plate 18 is linearly moved in the bending direction 20, and both are relatively linearly moved. At this time, since the tip of the optical fiber 1 is obliquely abutted against the polishing plate 18, the end faces of the optical fibers are collectively polished obliquely in the same direction.

According to the optical fiber polishing method of this embodiment,
Since the linear motion directions 19 and 20 are in one direction of the alignment direction of the tape optical fiber 9, a slope matching the one direction of the alignment direction of the tape optical fiber 9 is obtained, and is optimal for the optical fiber connector shown in FIG. .

Of course, the gripper 11 or the polishing plate 18
4A is not limited to the directions 19 and 20 shown in FIG. 4A, but may be any direction such as a direction perpendicular to the directions. An optical fiber inclined surface having a uniform direction can be formed.

Further, in this embodiment, as shown in FIG. 4B, each optical fiber 1 in the tape optical fiber 9 is gripped by the optical fiber gripper 11 at a length L1 'from the tip, and The part 11 is perpendicular to the polishing plate 18, and the distance between the gripping part 11 and the polishing plate 18 is set to a length L2 ′ (L2 ′ <L
1 ′) to bend the optical fiber 1, and in this state, the gripper 11 is made to circularly move in one direction 21, or the polishing plate 18 is made to circularly move in the opposite direction 22, By relatively making a circular motion between them, the tips of all the optical fibers 1 in the tape optical fiber 9 are chamfered at once.

Therefore, according to the present embodiment, there is an advantage that the chamfering of each slope can be performed continuously from the polishing in which the tip end faces of all the optical fibers 1 in the tape optical fiber 9 are sloped in the same direction.

The angle of the slope can be controlled by setting the ratio between L1 and L2, and the amount of chamfer is L1 'and L2'.
Can be controlled by setting the ratio of

The above optical fiber polishing method is applicable not only to the tape optical fiber 9 but also to a single-core optical fiber core wire. Beveling of slopes can be performed.

[0044]

As described above, according to the optical fiber connecting method, the optical fiber connector and the optical fiber polishing method of the present invention, a simple and small optical fiber having low reflection, low loss and capable of being arrayed. A connector can be provided.

That is, according to the optical fiber connecting method of the first aspect, an optical fiber having an inclined end surface is abutted in a hole having an inner diameter slightly larger than the outer diameter of the optical fiber without using a ferrule and a spring. By bending and fixing at the rear end, the slopes are surely connected in parallel by the elastic force of the optical fiber itself, so that a small-sized, low-reflection, low-loss optical fiber connection can be realized with a simple structure.

According to the optical fiber connection method of the second aspect, by chamfering the end face of the optical fiber having the slope, the area of the connection surface is reduced and the degree of adhesion of the connection surface is further increased. Thus, a lower loss optical fiber connection can be realized.

Further, according to the optical fiber connector according to the third aspect, without using a ferrule and a spring, an optical fiber having an inclined end face can be inserted into a hole having an inner diameter slightly larger than the outer diameter of the optical fiber. When the ends are bent and abutted, the slopes are securely connected in parallel by the elastic force of the optical fiber itself, so that a compact, low-reflection, low-loss optical fiber connector can be realized with a simple structure.

According to the optical fiber connector of the fourth aspect, since the inclined direction of the optical fiber in the tape optical fiber coincides with one direction of the alignment direction of the optical fiber, 2
When two optical fiber connectors are opposed to each other, the opposing optical fiber slopes always go down and can be connected without being turned upside down.

According to the optical fiber polishing method of the present invention, since the end face is polished by bending the optical fiber and moving linearly, the tip of the optical fiber can be set to a tape optical fiber in which a plurality of optical fibers are arrayed. With the alignment, the direction of the slope can be arbitrarily set and polished at once.

[Brief description of the drawings]

FIG. 1 is a view showing an optical fiber connection method according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an optical fiber connection method according to a second embodiment of the present invention.

FIG. 3 is a diagram showing an optical fiber connector according to a third embodiment of the present invention.

FIG. 4 is a diagram showing an optical fiber polishing method according to a fourth embodiment of the present invention.

FIG. 5 is a diagram showing a first conventional example.

FIG. 6 is a diagram showing a second conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical fiber 2 Bevel 3 Optical fiber core 4 Substrate 5, 5A Fixing member 6 Hollow member 7 Adhesive 8 Chamfering part 9 Tape optical fiber 10 Connector plug 11 Optical fiber holding part 12 Connector adapter 13 Tapered through hole 14 Slope direction 15 Passage 16, 17 Notch 18 Polishing plate 19, 20 Linear motion direction 21, 22 Circular motion direction LI, LI 'Length from optical fiber end face to gripping portion L2, L2' Distance between gripping portion and polishing plate θ Slant Every time

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Shigeyuki Mitachi 3-19-2 Nishishinjuku, Shinjuku-ku, Tokyo Nippon Telegraph and Telephone Corporation

Claims (5)

[Claims] In an optical fiber connecting method, the end faces of two optical fibers are inclined, and the end faces of two optical fibers are abutted with each other in a hole having an inner diameter slightly larger than the outer diameter of the optical fiber. An optical fiber connection method, wherein at least one optical fiber is bent and fixed. 2. The optical fiber connection method according to claim 1, wherein at least one of the end faces of the two optical fibers is chamfered. 3. A single-core or multi-core optical fiber connector, wherein the ends of the optical fibers obliquely inclined with respect to the optical axis are parallel to each other and have an inner diameter slightly larger than the outer diameter of the optical fiber. An optical fiber connector characterized in that the optical fiber at the rear end is bent and abutted. 4. An optical fiber connector for a tape optical fiber, wherein an optical fiber having each end face inclined obliquely with respect to an optical axis is mounted, and the direction of each inclined face is one direction of an optical fiber alignment direction in the tape optical fiber. In the hole having the inner diameter slightly larger than the outer diameter of the optical fiber, the slopes of the respective optical fibers are mounted in parallel, and the slopes of the respective optical fibers are parallel to each other. An optical fiber connector, wherein an optical fiber is bent and joined. 5. A method for polishing an end face of an optical fiber, wherein the optical fiber is gripped at a position of a certain length from the end face, a distance between the grip portion and the polishing member is set to be equal to or less than this length, and the grip portion and the polishing member are relatively positioned. An optical fiber polishing method, characterized in that the optical fiber is moved linearly.