JPH09133822A - End surface structure of optical fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a connection with an opposite-side optical component safely with low connection loss. SOLUTION: The end surface structure of an optical fiber having its core 3 coated with a clad 4 is formed by providing a slanting surface 6 which extends at an obtuse angle from one end side of the outer peripheral surface 9 of the optical fiber beyond the position of the core 3 and a vertical surface 8 which is formed from a position beyond the core 3 in the slanting surface 6 almost at right angles to the optical axis of the optical fiber 5. The connection end surface of the core 3 is formed into the slanting surface 6 slanting to a plane R perpendicular to the optical axis Z, and then light which is propagated in the core 3 and reflected by the connection end surface of the core 3 is reflected in a direction off the core 3 to suppress the return of the reflected light to the transmission side of the light, and this end surface structure is provided with no acute part having an acute angle to the outer peripheral surface 9 to prevent the end surface side from being broken.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an end face structure of an optical fiber used for optical communication or the like.

[0002]

2. Description of the Related Art For example, when inspecting and inspecting an optical transmission line or an optical transmission abnormality of a plurality of optical fiber cores (optical lines) of an optical circuit, an inspection device is applied to an optical line of each core on a wiring or circuit side. The optical line (optical fiber) on the side is switched and connected to inspect and inspect each heart, and an optical switch is used for the switching connection of the optical line.

FIG. 6 shows an example of a recently proposed optical switch. In the same figure, the optical fiber 5 on the receiving side is arranged and fixed in the optical fiber array member 1 formed by arranging a plurality of V-grooves 15 with the connecting end face 20 side thereof being depressed in the longitudinal direction of each V-groove 15. There is. This receiving optical fiber 5
A master optical fiber 16 fixed to a movable stage (not shown) movable in, for example, the X direction and the Y direction in the drawing is provided on the connection end face 20 side of the master optical fiber 16 by the movement of the master optical fiber 16. Connection end face of optical fiber 16
The 21 side is selectively inserted into one of the V grooves 15 of the optical fiber array member 1.

In this optical switch, for example, when the master optical fiber 16 is inserted in the V groove 15a,
The master optical fiber 16 and the receiving side optical fiber 5a are optically connected, and when the master optical fiber 16 is inserted into the V groove 15b as shown by the chain line in the figure, the master optical fiber 16 and the receiving side optical fiber 5b are separated from each other. The master optical fiber 16 and the receiving side optical fiber 5 are switchably connected in this way.

As is well known, a master optical fiber
As shown in FIG. 8, the optical fibers such as 16 and the optical fiber 5 on the receiving side are surrounded by the core 3 which is an optical path having a high refractive index.
It is formed so as to be covered with a clad 4 having a lower refractive index than the core 3, and the propagation light of the optical fiber propagates in the core 3.

By the way, in the above optical switch, it is necessary to align the end faces (connection end faces) 20 of the plurality of receiving side optical fibers 5 arranged and fixed in the optical fiber array member 1. Therefore, for example, as shown in FIG. 7, after the optical fibers 5 on the receiving side are inserted into the plurality of V-shaped grooves 15 arranged in a direction perpendicular to the paper surface and fixed by the adhesive 10, A plurality of optical fibers 5 are collectively cut by a dicing saw 11 or the like. With this arrangement, when the optical fiber 5 is arranged in the V-shaped groove 15, even if the connecting end face 20 side is not aligned like the optical fiber 5a, the cut surface by the dicing saw 11 connects the optical fiber 5 to each other. The end face 20 is formed, and the connection end faces 20 of all the optical fibers 5 are aligned.

[0007]

However, when the optical fiber 5 is cut by using the dicing saw 11 or the like as described above, the optical fiber 5 is cut when the dicing saw 11 cuts it.
Since a high-refractive index layer called a work-affected layer is formed on the cut surface of the optical fiber 5, when the light is propagated to the optical fiber 5, the light is reflected by the connection end surface 20 of the optical fiber 5 and the light transmitting side. Will return to. This causes a problem because it has an adverse effect when performing optical communication or inspection / inspection of an optical line using the optical switch having the optical fiber 5.

Therefore, when the optical fiber 5 is cut,
For example, as shown in FIG. 9, the connection end face 20 of the optical fiber 5 is
It is conceivable to form the optical fiber 5 on the oblique end face by inclining it by an angle θ (for example, θ = 8 °) from a plane R perpendicular to the optical axis Z of the optical fiber 5. Then, when the light propagates through the core 3 of the optical fiber 5 as shown in A of the figure and reaches the connection end face 20, the reflected light is reflected in a direction away from the core 3 as shown in A'of the figure. It will not return to the light transmission side.

However, as shown in the figure, when the connecting end face 20 of the optical fiber 5 is formed as an oblique end face, an acute angle portion 18 is formed in which the angle between the oblique end face and the outer peripheral surface 9 of the optical fiber 5 is an acute angle. Since the acute angle portion 18 is very easily chipped, for example, when the master optical fiber 16 is moved and inserted into the V groove 15 of the optical fiber array member 1 in the optical switch, the master optical fiber 16 is There was a problem in that the sharp corner 18 would be chipped if it made a slight contact with the sharp corner 18. Then, this chipped sharp edge 18
Exists as a foreign substance in the optical switch and adversely affects the accuracy of the optical switch, or when the acute angle portion 18 is missing, the core 3 side is also damaged, and the optical fiber 5 and the master optical fiber are damaged. Not only does it increase the optical connection loss with 16, but it is also dangerous when inspecting the optical switch.

Therefore, the master optical fiber 16 has an acute angle portion 18
It may be possible to increase the distance between the connection end faces of the optical fiber 5 on the receiving side and the master optical fiber 16 in order to prevent even a slight contact with the optical fiber. 5 and the master optical fiber 16 will be increased in connection loss.

The present invention has been made to solve the above-mentioned problems, and an object thereof is to prevent an adverse effect on the optical transmission side due to the reflection of light at the end face, and to connect an optical fiber on the other side. Another object of the present invention is to provide an end face structure of an optical fiber that can be safely connected to the above optical component with low connection loss.

[0012]

Means for Solving the Problems To achieve the above object, the present invention provides means for solving the problems by the following constitution. That is, the first aspect of the present invention is an end face structure of an optical fiber formed by covering a circumference of a core with a cladding, wherein the end face of the optical fiber has an obtuse angle from one end side of an outer peripheral face of the optical fiber. It is formed by having an oblique inclined surface extending beyond the core position and a vertical surface formed substantially perpendicular to the optical axis of the optical fiber from the position of the inclined surface beyond the core. Is configured.

The second aspect of the present invention is an end face structure of an optical fiber formed by covering a core with a clad, wherein the end face of the optical fiber extends from the outer peripheral side of the optical fiber toward the center. It is characterized in that it has a vertical surface formed substantially perpendicular to the optical axis of the optical fiber, and an oblique inclined surface that penetrates from the inner end side of the vertical surface to the inside beyond the core. There is.

In the first aspect of the present invention having the above-mentioned structure, an oblique inclined surface extending from the one end side of the outer peripheral surface of the optical fiber beyond the core 1 at an obtuse angle is formed, and the end surface (connection end surface) of the core is formed. Is in this inclined surface, when the light propagating through the core is reflected at the end face of the optical fiber, the reflected light is suppressed from being reflected in the direction away from the core and returning to the transmission side of the light. The light does not adversely affect the sender of the light.

Further, in the first aspect of the present invention, from the position beyond the core of the inclined surface, a vertical surface formed substantially perpendicular to the optical axis of the optical fiber is formed. Like an optical fiber having an end surface, the inclined surface extends beyond the core to the other end side of the outer peripheral surface of the optical fiber and forms an acute angle portion (formed by the inclined surface and the other end side of the outer peripheral surface of the optical fiber. It does not have an acute angle portion). Therefore, in the first aspect of the present invention, the acute-angled portion is not damaged unlike the conventional end face structure of an optical fiber having an oblique end face, and the damage of the core is not caused by the damage of the acute-angled portion. There is no risk of damage to the.

Therefore, when the optical fiber having the end face structure of the first aspect of the present invention is connected to an optical component such as an optical fiber on the other end of the connection, optical connection can be safely performed, and adverse effects due to reflection at the connection end face are exerted. No increase in connection loss or the like due to damage to the connection end surface or the like. Moreover, in the first aspect of the present invention, a vertical surface is formed from a position beyond the core of the inclined surface, and the end face of this optical fiber is connected to the connection partner side rather than the end face of the optical fiber having an acute angle portion. Since it is possible to bring it closer to the end face, it becomes possible to perform optical connection with a low connection loss, and the above problem is solved.

Also in the second aspect of the present invention having the above-mentioned structure, the connecting end face of the core is an inclined face that goes into the inside beyond the core from the inner end side of the vertical face formed from the outer peripheral edge side of the optical fiber toward the center. In addition, since the surface formed inside the optical fiber and in contact with the outer peripheral edge does not form an acute-angled portion whose angle with the outer peripheral edge forms an acute angle, the connection partner Side optical components are safely connected, and
The above problem is solved without adverse effects of reflected light on the connection end face and damages of the connection end face.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. In the description of the present embodiment, the same reference numerals are given to the same parts as those in the conventional example, and the overlapping description will be omitted. FIG. 1 is a sectional view showing a first embodiment of the end face structure of an optical fiber according to the present invention, and FIG. 2 is a perspective view thereof. The optical fiber of the present embodiment is arranged and fixed in the optical fiber array member 1 as the optical fiber 5 on the receiving side of the optical switch as shown in FIG. 6, for example.

In FIGS. 1 and 2, the end face (connection end face 20) of the optical fiber 5 exceeds the position of the core 3 with an obtuse angle α (α = 98 °) from one end side of the outer peripheral face 9 of the optical fiber 5. The slanting inclined surface 6 that extends and the core 3 of this inclined surface 6
And a vertical surface 8 that is formed substantially perpendicular to the optical axis Z of the optical fiber 5 from a position beyond the above position. The inclined surface is inclined by an angle θ from the surface R perpendicular to the axis Z, and the vertical surface 8 is formed by removing the acute angle portion 18 as shown in FIG.

The embodiment is constructed as described above. Next, a method of forming the end face structure of the optical fiber 5 will be described with reference to FIG. Note that, also in the present embodiment example, as in the conventional example shown in FIG. 7, the optical fiber 5 is arranged in each V groove 15 of the optical fiber arranging member 1 and the adhesive is applied.
After being fixed at 10, the operation of collectively cutting the plurality of optical fibers 5 by the dicing saw 11 is performed.
In the figure, the V groove of the optical fiber array member 1 is omitted. Further, in the present embodiment example, the escape groove 13 is formed in the optical fiber array member 1 so as to correspond to the position where the optical fibers 5 are collectively cut by the dicing saw 11.

First, as shown in FIG. 3A, an adhesive
The connection end face 20 side of the optical fiber 5 fixed to the optical fiber array member 1 by 10 is obliquely cut by the dicing saw 11. In the present embodiment example, the optical fiber 5
The adhesive 10 used to fix the optical fiber array member 1 to the optical fiber array member 1 is a water-soluble ultraviolet curable adhesive,
After applying the adhesive 10 to the connection end face side of the optical fiber 5,
The adhesive 10 is hardened by ultraviolet rays to fix the optical fiber 5, but the adhesive 10 can be easily removed after that if necessary. Then, when the cut end of the optical fiber 5 and the adhesive 10 cut by the dicing saw 11 are removed, the connection end face 20 of the optical fiber 5 is formed on the slanted inclined face 6 as shown in FIG. .

Next, as shown in (c) of FIG.
In order to prevent the chip 18 from being chipped, the entire connecting end face 20 side of the optical fiber 5 including the inclined surface 6 is covered again with the adhesive 10, and the dicing saw 11 is placed in a direction perpendicular to the optical axis Z of the optical fiber 5. As shown in (d) of the same figure, the vertical surface 8 is moved from the position beyond the core 3 of the inclined surface 6 to remove the acute angle portion 18 formed in the state of (b) of the same figure. To form. Then, if necessary, the adhesive 10 on the connection end face side of the optical fiber 5 is partially removed.

According to the present embodiment, as described above, the inclined surface 6 extending from the one end side of the outer peripheral surface of the optical fiber 5 beyond the core 3 is formed, and the end surface of the core 6 is within this inclined surface. Since it is inclined at an angle, it becomes possible to reflect the reflected light at the connection end face of the optical fiber 5 in the direction away from the core 3 as in the optical fiber 5 shown in FIG. It is possible to suppress the adverse effect of returning to the transmission side of.

Moreover, according to this embodiment, unlike the optical fiber 5 shown in FIG. 9, the outer peripheral surface 9 of the optical fiber 5 is different.
Since the acute angle portion 18 having an acute angle is not formed, the acute angle portion 18 is not chipped, and the risk of damage to the acute angle portion 18 and damage to the core 3 can be suppressed. Therefore, the optical fiber 5 is not adversely affected by the breakage of the acute angle portion 18, and in the optical switch to which the optical fiber 5 is applied, the connection between the optical fiber 5 and the master optical fiber 16 can be performed safely and with low connection. Can be connected at loss.

Further, according to the present embodiment, the acute angle portion 18
Since the vertical surface 8 which is substantially perpendicular to the optical axis Z of the optical fiber 5 is removed, the master optical fiber 16 can be brought closer to the optical fiber 5 as compared with an optical fiber having an acute angle portion 18. It is also possible to reduce the connection loss due to the gap between the connection end faces of the optical fiber 5 and the master optical fiber 16. Therefore, this optical fiber 5
It is possible to further reduce the connection loss between the master optical fiber 16 and the master optical fiber 16. By applying the optical fiber 5 to the optical switch, the switchable optical connection with the master optical fiber is safe and low in connection. It is possible to construct an excellent optical switch that can be performed with loss.

FIG. 4 is a sectional view showing a second embodiment of the end face structure of an optical fiber according to the present invention.
In the figure, the end face (connection end face 20) of the optical fiber 5 is
From the outer peripheral edge side (edge side of the outer peripheral surface 9) of the optical fiber 5 toward the center, the vertical surfaces 8 (8a, 8b) formed substantially perpendicular to the optical axis Z of the optical fiber 5 and the vertical surface 8a. It has a slanted inclined surface 6 that goes into the inside from the inner end side beyond the core 3, and the slanted surface 7 is provided between the inner end side of this inclined surface 6 and the inner end side of the vertical surface 8b. ing. Since the example of the present embodiment is configured as described above, in the example of the present embodiment as well, similarly to the example of the first embodiment described above, the end surface of the core 3 is formed as an inclined surface formed in the inclined surface 6. In addition, this embodiment also has a configuration that does not have the acute angle portion 18 as shown in FIG.

The example of the present embodiment is configured as described above. Next, the manufacturing method of the example of the present embodiment will be described with reference to FIG. In the present embodiment, as in the case of the first embodiment, the optical fiber 5 on the receiving side of the optical switch as shown in FIG. 6 is arranged and fixed to the optical fiber arranging member 1. Also in FIG. 5, the V groove of the optical fiber array member 1 is omitted. First, FIG. 5 (a)
As shown in FIG. 6, in the present embodiment as well, the connection end face 20 side of the optical fiber 5 is fixed to the optical fiber arranging member 1 by the adhesive 10 as in the first embodiment, and the dicing saw 11
Is used to make an oblique cut on the connection end face 20 side of the optical fiber 5. Unlike this first embodiment, this cut is made in a direction in which the angle β formed by the outer peripheral surface 9 of the optical fiber 5 becomes an acute angle, and the dicing saw 11 is stopped at a position beyond the core 3.

Then, as shown in FIG.
On the connection end face 20 side of the optical fiber 5, an inclined surface 6 extending from one end side of the outer peripheral surface 9 to a position beyond the core 3 is formed. Next, as shown in (c) of the figure, as in the first embodiment, the connecting end face 20 side of the optical fiber 5 is again covered with the adhesive 10, and the dicing saw 11 is covered with the optical fiber 5.
The optical fiber 5 is cut down by being lowered perpendicularly to the optical axis Z of. Then, as shown in (d) of the same figure, a vertical surface 8a is formed between the outer end side of the inclined surface 6 and the outer peripheral side of the optical fiber 5, and also from the inner end side of the inclined surface 6 via the inclined surface 7. A vertical surface 8b is formed on the outer peripheral surface 9 of the optical fiber 5.

According to this embodiment, the connection end face of the core 3 is formed in the inclined surface 6 which is inclined with respect to the optical axis Z of the optical fiber 5, as in the first embodiment. Since it has an inclined surface and does not have an acute angle portion 18 like the conventional optical fiber 5 shown in FIG. 9, the same effect as that of the first embodiment can be obtained. it can.

Further, according to the present embodiment, the inclined surface 6 is formed as an inclined surface which penetrates from the inner end side of the vertical surface 8a to the inner side beyond the core 3, so that the connecting end surface of the core 3 faces outward. The connection end face of the core 3 is less likely to be damaged than in the case where the core 3 is formed so as not to increase the connection loss due to the damage of the core 3. It is possible to more reliably prevent an increase in connection loss with components.

The present invention is not limited to the above-described embodiment, but can adopt various embodiments. For example,
In the second embodiment, the slope 7 is formed between the inclined surface 6 and the vertical surface 8b, but instead of the slope 7, for example,
The surface 23 (for example, a vertical surface) and the surface 24 (for example, a horizontal surface) of FIG. 5D may be provided between the inclined surface 6 and the vertical surface 8b.

Further, in the above-mentioned embodiment example, FIG.
And, as shown in FIG. 5B, after forming the inclined surface 6 on the connection end face side of the optical fiber 5, as shown in FIG. 3C and FIG. The vertical end faces 8, 8a, 8b were formed by the dicing saw 11 after covering the connecting end face side of the optical fiber 5 with the adhesive 10, but the sharp corner portion 18 was removed without covering the connecting end face side of the optical fiber 5 with the adhesive 10. The vertical surfaces 8, 8a, 8b may be formed.

Further, in the above-mentioned embodiment, the adhesive 10 is an ultraviolet curable water-soluble adhesive, but the nature of the adhesive 10 is not particularly limited, and the end face structure of the optical fiber 5 can be changed. Any material may be used as long as it can be easily removed from the connection end face side of the optical fiber 5 after being formed.

Further, in the above embodiment, the inclined surface 6 has an angle θ (θ = 8) from the surface R perpendicular to the optical axis Z of the optical fiber 5.
Although the inclined surface is inclined at an angle, the angle of the inclined surface 6 with respect to the optical axis Z or the surface R is not particularly limited, and may be an angle inclined from the surface R by 4 ° or more, for example.

Further, in the above embodiment, the end face structure of the receiving side optical fiber 5 arranged and fixed to the optical fiber array member 1 of the optical switch as shown in FIG. 6 has been described as an example. The end face structure of the optical fiber of the present invention is also applied as an end face structure of various optical fibers used for optical components other than the optical switch, and the end face structures of the plurality of optical fibers 5 are collectively formed. Not only when
It is also applied as an end face structure of an independent optical fiber of a book.

[0036]

According to the present invention, in the first aspect of the present invention, an oblique inclined surface extending beyond the core position at an obtuse angle from one end side of the outer peripheral surface of the optical fiber, and the optical axis of the optical fiber. And a vertical surface formed substantially perpendicular to the optical fiber. In the second aspect of the present invention, the end surface of the optical fiber is oriented from the outer peripheral side of the optical fiber toward the center with respect to the optical axis of the optical fiber. In each case, the connecting end surface of the core is formed as an inclined surface because it has a vertical surface that is formed substantially vertically and an inclined inclined surface that goes inward from the inner end side of the vertical surface beyond the core. The reflected light that propagates through the core and is reflected by the connection end face can be reflected in a direction away from the core. Therefore, it is possible to prevent the reflected light from returning to the light transmitting side to adversely affect the optical communication and the inspection and inspection of the optical system.

Further, according to the present invention, with the above-described structure, the angle between the vertical surface and the inclined surface formed from the outer peripheral surface of the optical fiber toward the center is substantially vertical or obtuse. Since the optical fiber does not have an acute angle portion where the angle formed between the outer peripheral surface of the optical fiber and the connection end surface is an acute angle portion, unlike the conventional optical fiber having this acute angle portion, It is possible to suppress the danger due to the lack of the connector and increase in the connection loss with the optical component on the connection partner side. Moreover, since the optical fiber having the end face structure of the present invention can be brought closer to the connection end face of the optical component on the other end of the connection, the loss due to the gap between the connection end faces can be reduced by the amount not having the acute angle portion. Therefore, it is possible to obtain an excellent optical fiber that can be connected to the optical component on the connection partner side with low connection loss.

[Brief description of the drawings]

FIG. 1 is a sectional configuration diagram showing a first embodiment of an end face structure of an optical fiber according to the present invention.

FIG. 2 is a perspective view of the example embodiment.

FIG. 3 is an explanatory diagram showing an example of an end face structure forming method of the embodiment.

FIG. 4 is a sectional configuration diagram showing a second embodiment of the end face structure of the optical fiber according to the present invention.

FIG. 5 is an explanatory diagram showing an example of an end face structure forming method of the second embodiment.

FIG. 6 is an explanatory diagram of an optical switch of a type that directly moves a master optical fiber.

FIG. 7 is an explanatory diagram showing a method for forming an end face structure of an optical fiber on the receiving side used in the optical switch shown in FIG.

FIG. 8 is an explanatory diagram showing a cross-sectional structure of a general optical fiber.

FIG. 9 is an explanatory view showing an end face structure of a conventional optical fiber in which a connection end face is formed as an oblique end face.

[Explanation of symbols]

 3 core 4 clad 5 optical fiber 6 inclined surface 8, 8a, 8b vertical surface 9 outer peripheral surface

Front page continuation (72) Inventor Naoki Nakao 3-19-2 Nishishinjuku, Shinjuku-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Takashi Ebihara 3-19-3 Nishishinjuku, Shinjuku-ku, Tokyo Nippon Telegraph and Telephone Corporation Phone Co., Ltd.

Claims (2)

[Claims] 1. An end face structure of an optical fiber formed by covering a core with a clad, wherein the end face of the optical fiber exceeds the core position with an obtuse angle from one end side of an outer peripheral face of the optical fiber. And a vertical surface that is formed substantially perpendicular to the optical axis of the optical fiber from a position beyond the core of the inclined surface. Optical fiber end face structure. 2. An end face structure of an optical fiber formed by covering a core with a clad, the end face of the optical fiber being directed from the outer peripheral edge side of the optical fiber toward the center with respect to the optical axis of the optical fiber. An end face structure of an optical fiber, which has a vertical surface formed substantially vertically and an inclined surface inclined from the inner end side of the vertical surface to the inside beyond the core.