JP2010139526A - Method of manufacturing optical connector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing an optical connector which is useful in the case that the outer diameter of an optical fiber applied to an optical connector is widely different from the diameter of a fine hole formed in a ferrule. <P>SOLUTION: In manufacturing an optical connector with an optical fiber built in for a roughly columnar ferrule with a fine hole formed longitudinally, an optical fiber with a coating removed at the tip end is inserted from one end of the fine hole, and the tip end of the optical fiber is exposed from the other end thereof by a prescribed length to form an increased diameter part having an isotropic shape in the radial direction of the optical fiber, at the tip end of the optical fiber. Then, with the ferrule held, the optical fiber is pulled back to seal the other end of the fine hole, by the increased diameter part. Thereafter, the ferrule and the optical fiber are bonded to each other, the end face of the other end of the ferrule is polished, and alignment of the end faces of the optical fiber is performed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an optical connector, and more particularly to a technique useful when the outer diameter of an optical fiber applied to the optical connector is far from the hole diameter of a fine hole formed in a ferrule.

Conventionally, various optical connectors have been put to practical use in order to detachably connect optical fibers in an optical fiber connection section such as an optical transmission device. For example, JIS C 5973 defines a single-fiber optical connector called a SC type (so-called SC connector).
For example, Patent Documents 1 and 2 are known as conventional techniques related to this optical connector.

FIG. 7 is a cross-sectional view showing a schematic configuration of a conventional optical connector.
As shown in FIG. 7, the optical connector 10 includes an optical fiber core wire (hereinafter referred to as an optical fiber) 11 in which an optical fiber 111 is covered with a coating layer 112, an optical fiber holding fitting 12, and a ferrule 13. And.
The optical fiber holding metal fitting 12 has an insertion hole 12 a for inserting the optical fiber 11 and a ferrule holding portion 12 b for holding the ferrule 13.
The ferrule 13 has an introduction part 13b for introducing the optical fiber 11 and a pore 13a that is connected to the introduction part 13b and passes through the optical fiber element 111. The ferrule 13 is fitted into the optical fiber holding metal fitting 12 and fixed integrally therewith. Is done. The introduction portion 13b is formed in a tapered shape so as to reduce the diameter from the diameter capable of introducing the optical fiber 11 to the diameter of the pore 13a.
By inserting the optical fiber 11 from which the coating layer 112 at the front end portion is removed into the insertion hole 12a of the optical fiber holding fitting 12, and further inserting the optical fiber 111 into the pore 13a of the ferrule 13, FIG. The optical connector 10 shown in FIG. In addition, although illustration is abbreviate | omitted, the outer peripheral surface of the optical fiber strand 111 and the inner surface of the pore 13a are adhere | attached with adhesives, such as a thermosetting resin.

  In an optical fiber connection portion such as an optical transmission device, two optical connectors 10 are inserted from both sides into an adapter incorporating a cylindrical split sleeve for aligning the ferrules 13, and the end surfaces of the ferrules 13 are abutted so that the optical fiber The strand 111 is connected by PC (Physical Contact). That is, the ferrule 13 is inserted into the split sleeve of the adapter, and the optical connector 10 is aligned by the outer peripheral surface of the ferrule 13.

At this time, since the optical fiber strands 111 inserted into the fine holes 13a of the ferrule 13 need to be PC-connected with high accuracy, the inner peripheral surface accuracy of the split sleeve and the outer peripheral surface accuracy of the ferrule 13 (outer diameter accuracy). ) Is very highly controlled.
The fine holes 13a of the ferrule 13 are formed so that the center of the fine holes 13a and the center of the outer diameter of the ferrule 13 coincide with each other with high accuracy. Further, the diameter of the pore 13a is substantially the same as the diameter of the optical fiber 111 so that the central axis of the optical fiber 111 is stably positioned at the center of the pore 13a. Since the conventional optical fiber 111 has an outer diameter of 0.125 ± 0.001 mm, the pore 13a of the ferrule 13 is, for example, about 0.1255 mm.
Thus, by controlling the shape (outer diameter dimension) of the ferrule 13 and the hole diameter dimension / position of the pore 13a with extremely high accuracy, high optical characteristics are realized in the optical fiber connection portion.
JP-A-61-63806 Japanese Patent Laid-Open No. 55-22707

  As described above, the conventional optical fiber strands are standardized to have an outer diameter of 0.125 ± 0.001 mm, and the manufacturer manufactures optical fiber strands based on this. Therefore, in the manufacture of an optical fiber, a technique for realizing a standardized outer diameter with high accuracy has been established. Further, since a standardized optical fiber strand with an outer diameter is applied to the optical connector, it is possible to form fine holes with high precision in the ferrule, and it is provided as a general-purpose ferrule.

By the way, in recent years, research and development of special optical fibers having an outer diameter (for example, 0.400 mm) different from the above-described standardized outer diameter has been advanced.
However, with the current optical fiber manufacturing technology, the outer diameter of the optical fiber cannot be freely controlled with high accuracy. For example, even if an optical fiber is manufactured with an outer diameter of 0.400 mm as a target, an error of several tens of μm or more may occur.
And since the outer diameter of an optical fiber strand cannot be controlled with high precision, it is also difficult to manufacture an optical connector to which this optical fiber strand is applied. In other words, the ferrule pores need to be formed so as to be approximately the same as the outer diameter of the optical fiber, but in order to form a highly accurate pore according to the outer diameter of the optical fiber. A dedicated processing facility is required, and the manufacturing cost of the ferrule becomes expensive.

On the other hand, if the pore diameter of the ferrule pores is made relatively large, an optical fiber strand having an outer diameter smaller than the pores can be inserted. However, in this case, since the gap between the fine hole and the optical fiber strand is large, it is extremely difficult to fix them so that the center axis of the optical fiber strand coincides with the center of the fine hole.
For example, when a 0.380 mm optical fiber strand is inserted and fixed in a pore having a pore diameter of 0.430 mm, the center axis of the optical fiber strand is biased toward the edge of the pore, and the center-to-center distance is 0.03 to 0. .04mm.
If the center axis of the optical fiber is displaced from the center of the pore, even if the end face of the ferrule 13 is abutted on the adapter, a good PC connection cannot be obtained, and it is difficult to realize high optical characteristics. It becomes.

  The present invention is a method for manufacturing an optical connector, and in particular, provides a technique useful when the outer diameter of an optical fiber applied to the optical connector is far from the hole diameter of the pore formed in the ferrule. And

In order to achieve the above object, the present invention is a method of manufacturing an optical connector in which an optical fiber is built in a substantially cylindrical ferrule having pores formed in the length direction,
A first step of inserting the optical fiber from which the coating of the tip portion is removed from one end side of the pore and exposing the tip portion of the optical fiber from the other end side by a predetermined length;
A second step of forming a diameter-increased portion having an isotropic shape in the radial direction of the optical fiber at the tip of the optical fiber;
A third step of holding the ferrule, pulling back the optical fiber, and sealing the other end of the pore with the increased diameter portion;
A fourth step of bonding the ferrule and the optical fiber;
A fifth step of polishing the end face of the other end side of the ferrule to end the end face of the optical fiber;
It is characterized by providing.

  Preferably, in the second step, a resin solution droplet is attached to the tip of the optical fiber, and the diameter-enlarged portion is formed by curing the droplet while the optical fiber is held vertically. It is characterized by doing.

  Preferably, in the second step, the liquid droplets are adhered by dipping the tip of the optical fiber in a resin solution and then pulling it up.

  Preferably, in the second step, when the droplet is cured, the optical fiber is rotated about an axis.

  Preferably, the resin solution is a UV curable resin.

  Preferably, before performing the first step or the second step, the end surface of the end portion of the optical fiber is subjected to an end surface treatment so as to have a uniform surface property.

  According to the present invention, even if the outer diameter of the optical fiber and the pore diameter of the ferrule are far apart, the optical fiber is aligned with the ferrule so that the center of the optical fiber coincides with the center of the pore. Therefore, an optical connector to which various optical fibers having different outer diameters are applied can be manufactured relatively easily.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an explanatory view showing each step in the method of manufacturing an optical connector according to this embodiment, and FIG. 2 is a cross-sectional view showing a schematic configuration of the optical fiber holding metal 12 and the ferrule 13 used in this embodiment. In addition, the same code | symbol as FIG. 7 is attached | subjected about the member or site | part similar to the past.

In the present embodiment, as shown in FIG. 1, an optical fiber 11 in which an optical fiber 111 having a core and a clad (both not shown) is covered with a coating layer 112 is used as an optical fiber holding bracket (flange) 12. A case where a single-fiber optical connector (so-called SC connector) is manufactured by attaching to the ferrule 13 will be described.
Here, the outer diameter of the optical fiber 11 is, for example, 0.5 mm, and the outer diameter of the optical fiber 111 is, for example, 0.380 mm. Further, the tip of the optical fiber 11 (the optical fiber 111) is cut with a fiber cutter and subjected to an end face treatment so as to have a uniform surface property.

As shown in FIG. 2, the optical fiber holding metal fitting 12 has an insertion hole 12 a for inserting the optical fiber 11 and a ferrule holding portion 12 b for holding the ferrule 13.
The hole diameter of the insertion hole 12a of the optical fiber holding fitting 12 is not particularly limited as long as the optical fiber 11 can be inserted. In this embodiment, in order to simplify the description, the hole diameter of the insertion hole 12a of the optical fiber holding metal fitting 12 and the outer diameter of the optical fiber 11 are the same.

The ferrule 13 is a substantially cylindrical zirconia molded body, and has an introduction portion 13b for introducing the optical fiber 11 and a pore 13a that is connected to the introduction portion 13b and through which the optical fiber 111 is inserted. The fiber holding fitting 12 is fitted and fixed integrally.
The pore 13 a is formed in the length direction of the ferrule 13. The hole diameter of the fine holes 13a is, for example, 0.430 mm, and the difference from the outer diameter of the optical fiber 111 is 0.05 mm.
The introduction portion 13b is formed in a tapered shape so as to reduce the diameter from the diameter capable of introducing the optical fiber 11 to the diameter of the pore 13a. That is, the end surface 112a of the coating layer 112 of the optical fiber 11 is stopped at the introduction portion 13b.
In order to bond the optical fiber 11 (the optical fiber 111) and the ferrule 13, the pores 13a are filled with a thermosetting resin 15 in advance.

  As shown in FIG. 1A, first, the coating layer 112 is removed from the one end of the optical fiber 11 by a predetermined length. At this time, the length of the exposed optical fiber 111 is determined according to the length of the pore 13a of the ferrule 13 and the like. For example, when the optical fiber 111 is inserted into the pore 13a and the end surface 112a of the coating layer 112 of the optical fiber 11 is stopped by the introduction portion 13b, the tip 111a of the optical fiber 111 is formed in the pore 13a. To a predetermined length exposed to the outside.

Next, in FIG. 1B, the optical fiber 11 from which the coating layer 112 has been removed and the optical fiber 111 is exposed is inserted into the insertion hole 12a of the optical fiber holding metal fitting 12, and further the pore 13b through the introduction portion 13b. The tip end portion 111a of the optical fiber 111 is exposed by a predetermined length (for example, 10 mm) from the other end side.
At this time, since the pores 13 a of the ferrule 13 are filled with the thermosetting resin 15 as shown in FIG. 2, the thermosetting resin 15 adheres to the tip 111 a of the optical fiber 111. Therefore, the thermosetting resin 15 attached before the process of FIG. 1C is removed.

FIG. 3 is a cross-sectional view of the optical fiber holding metal fitting 12, the ferrule 13, and the optical fiber 11 after the process shown in FIG.
As shown in FIG. 3, after the step of FIG. 1B, the end surface 112a of the coating layer 112 of the optical fiber 11 is stopped at the introducing portion 13a, and the tip portion 111a of the optical fiber 111 is exposed to the outside. It becomes a state. Further, the gap between the optical fiber 111 and the pore 13 a is filled with a thermosetting resin 15.

  Next, in FIG. 1C, after the tip 111a of the optical fiber 111 is immersed in the UV resin solution 14, the tip 111a is pulled up from the UV resin solution 14 so that the UV resin solution 14 is applied to the tip 111a. Droplet is attached. At this time, since the shape of the droplet is governed by the surface tension and gravity of the UV resin solution 14, if the optical fiber 11 is held vertically, the droplet is isotropic in the radial direction of the optical fiber 11. It becomes a shape. Since the end face treatment is performed on the optical fiber 111, there is no possibility that the shape of the droplet depends on the surface property of the end face of the optical fiber 111.

  Here, the UV resin solution 14 has a diameter in which the droplets adhering to the surface of the optical fiber 111 are thicker than the diameter of the pores 13a (however, the diameter can be press-fitted into the openings 13c of the pores 13a). And having wettability and viscosity so as to have an isotropic shape in the radial direction of the optical fiber 11 in accordance with surface tension and gravity. In addition, it is desirable that the surface has an appropriate elasticity (can be deformed) after the droplets are cured by the process shown in FIG.

In FIG.1 (d), the droplet of the UV resin solution adhering to the front-end | tip part 111a of the optical fiber strand 111 is irradiated with an ultraviolet-ray, and is hardened. At this time, by holding the optical fiber 11 vertically, a diameter-increasing portion 14a having an isotropic shape in the radial direction of the optical fiber 11 is formed at the distal end portion 111a.
Further, by curing the droplet while rotating the optical fiber 11, the diameter of the increased diameter portion 14a can be controlled while maintaining the isotropic shape in the radial direction of the optical fiber 11.
In the step of FIG. 1D, only the UV resin droplets are cured, and the thermosetting resin 15 in the pores 13a is not cured.

In FIG.1 (e), the optical fiber 11 is pulled back in the state which hold | maintained the ferrule 13, the enlarged diameter part 14a is press-fit in the opening 13c of the fine hole 13a, and it seals.
At this time, the end face of the ferrule 13 is in the state shown in FIG. That is, the opening 13c of the pore 13a is sealed by the top of the increased diameter portion 14a. Further, since the increased diameter portion 14a has an isotropic shape in the radial direction of the optical fiber 11, the optical fiber 111 is positioned at the center of the pore 13a.
And the ferrule 13 and the optical fiber 11 (optical fiber strand 111) are adhere | attached by performing the heat processing (for example, 100 degreeC, 1h) and hardening to the thermosetting resin 15 with which the pore 13a was filled. Thereby, the optical fiber 111 is fixed in a state of being located at the center of the pore 13a.

  In FIG. 1 (f), the end surface of the optical fiber 111 is exposed by polishing the side sealed by the increased diameter portion 14 a of the ferrule 13. And the optical connector 10 is completed according to the above process. The optical connector 10 is distributed as a product by being housed in a housing (not shown).

FIG. 5 is a cross-sectional view of the optical connector 10 after the step shown in FIG. FIG. 6 is a bottom view of the optical connector 10 as viewed from below.
As shown in FIG. 5, after the step of FIG. 1 (f), the end surface 112a of the coating layer 112 of the optical fiber 11 is slightly lifted upward from the introduction portion 13a. As shown in FIGS. 5 and 6, the bottom surface of the ferrule 13 has the optical fiber 111 and the pore 13a concentrically positioned, and the gap between the optical fiber 111 and the pore 13a is UV curable resin (increase). (Diameter portion) 14a is sealed.

  As described above, in the method of manufacturing the optical connector according to the present embodiment, the optical fiber 11 (optical fiber strand 111) from which the coating of the tip portion is removed is inserted from one end side of the pore 13a, and the other end side is inserted. From the first step (FIGS. 1A and 1B) in which the tip 111a of the optical fiber 111 is exposed by a predetermined length, the tip 111a of the optical fiber 111 is connected to the tip of the optical fiber 11 A second step (FIGS. 1C and 1D) for forming an enlarged diameter portion 14a having an isotropic shape in the radial direction is provided. Next, the ferrule 13 is held, the optical fiber 11 is pulled back, and the pores 13a are formed. A third step (FIG. 1 (e)) for sealing the other end of the optical fiber with the increased diameter portion 14a; a fourth step (FIG. 1 (e)) for bonding the ferrule 13 and the optical fiber 111; The end face of the optical fiber 111 is polished by polishing the end face on the end side. Fifth step of performing tooth (Fig. 1 (f)), comprising a.

  Thereby, even if the outer diameter of the optical fiber 111 and the hole diameter of the fine hole 13a of the ferrule are separated from each other, the center of the optical fiber 111 coincides with the center of the fine hole 13a. Can be fixed to the ferrule 13. Therefore, it is not necessary to use the ferrule 13 in which the pores 13a are formed according to the outer diameter of the optical fiber 111.

And the optical connector which applied various optical fibers from which an outer diameter differs can be manufactured comparatively easily using the ferrule 13 in which the pore 13a of the same diameter was formed. For example, in this embodiment, since the ferrule 13 having the pores 13a having the hole diameter of 0.430 mm is used, the optical fiber 11 is applied if the outer diameter of the optical fiber 111 is 0.430 mm or less. An optical connector can be manufactured.
In the future, when manufacturing an optical connector to which a small-diameter optical fiber (for example, 0.080 mm) is applied, a currently used general-purpose ferrule (pore diameter 0.125 mm) may be used. It becomes possible.

As mentioned above, although the invention made by this inventor was concretely demonstrated based on embodiment, this invention is not limited to the said embodiment, It can change in the range which does not deviate from the summary.
In the above-described embodiment, the UV resin solution 14 is attached to the distal end portion 111a of the optical fiber 111 and cured to form the increased diameter portion 14a. However, the diameter of the optical fiber 10 can be increased by other methods. You may make it form the enlarged diameter part 14a which has an isotropic shape in a direction.
For example, a thermosetting resin can be used instead of the UV resin. In this case, care should be taken so that the thermosetting resin 15 that bonds the ferrule 13 and the optical fiber 111 is not cured by the curing process of the thermosetting resin constituting the increased diameter portion 14a.

  Further, for example, the increased diameter portion 14a can be formed by heating and melting the tip portion 111a of the optical fiber 111 by electric discharge or the like. In addition, a member (for example, a conical or bell-shaped member) formed in an isotropic shape in advance to form the increased diameter portion 14 a may be attached to the distal end portion 111 a of the optical fiber 111. Good.

Moreover, although the said embodiment demonstrated the manufacturing method of the optical connector for single cores, it is applicable also when manufacturing the optical connector for multi-fibers.
In the above embodiment, the optical connector 10 using the optical fiber 11 having the optical fiber 111 composed of the core and the clad has been described. However, a photonic crystal fiber (PCF) can also be applied. . In this case, before inserting the optical fiber 111 into the ferrule 13, it is desirable that the holes of the PCF are embedded in advance with UV resin or the like. Thereby, it can prevent that a fiber characteristic falls by the thermosetting resin 15 and refuse entering a void | hole.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is explanatory drawing shown about each process in the manufacturing method of the optical connector which concerns on this embodiment. It is sectional drawing shown about schematic structure of the optical fiber holding | maintenance metal fitting 12 and the ferrule 13 used by this embodiment. It is sectional drawing of the optical fiber holding metal fitting 12, the ferrule 13, and the optical fiber 11 after the process shown in FIG.1 (b). It is an enlarged view which shows the sealing state by the enlarged diameter part 14a in the lower end part of the ferrule 13. FIG. It is sectional drawing of the optical connector 10 after the process shown in FIG.1 (f). It is the bottom view which looked at the optical connector 10 from the downward direction. It is sectional drawing which shows schematic structure of the conventional optical connector.

Explanation of symbols

10 Optical connector 11 Optical fiber (optical fiber core wire)
111 Optical Fiber Strand 111a Tip 112 Cover Layer 12 Optical Fiber Retaining Bracket (Flange)
13 Ferrule 14 UV resin solution 14a Increased diameter part

Claims (6)

An optical connector manufacturing method in which an optical fiber is built in a substantially cylindrical ferrule having pores formed in a length direction,
A first step of inserting the optical fiber from which the coating of the tip portion is removed from one end side of the pore and exposing the tip portion of the optical fiber from the other end side by a predetermined length;
A second step of forming a diameter-increased portion having an isotropic shape in the radial direction of the optical fiber at the tip of the optical fiber;
A third step of holding the ferrule, pulling back the optical fiber, and sealing the other end of the pore with the increased diameter portion;
A fourth step of bonding the ferrule and the optical fiber;
A fifth step of polishing the end face of the other end side of the ferrule to end the end face of the optical fiber;
An optical connector manufacturing method comprising:   In the second step, a droplet of a resin solution is attached to the tip of the optical fiber, and the diameter-enlarged portion is formed by curing the droplet while the optical fiber is held vertically. The method of manufacturing an optical connector according to claim 1.   3. The method of manufacturing an optical connector according to claim 2, wherein, in the second step, the liquid droplets are attached by dipping the tip of the optical fiber in a resin solution and then pulling it up.   4. The method of manufacturing an optical connector according to claim 2, wherein, in the second step, when the droplet is cured, the optical fiber is rotated about an axis. 5.   The method for manufacturing an optical connector according to claim 2, wherein the resin solution is a UV curable resin.   6. The end surface of the end portion of the optical fiber is treated so as to have a uniform surface property before performing the first step or the second step. 6. Optical connector manufacturing method.

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