JP2002174753A - Ferrule for optical fiber connector and structure of optical fiber connector using the ferrule - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical fiber connector ferrule that facilitates and ensures coupling in a part for connecting the end of optical fibers to each other, and also to provide an optical fiber connector structure that employs this ferrule. SOLUTION: This optical fiber connector ferrule unit consists of two ferrules, one that is provided with an optical fiber inserting hole in the optical fiber connector part and the other that is arranged oppositely to the one ferrule on the same axial line. In such a ferrule unit, the front part of the one ferrule is a conical male projected body while that of the other ferrule is a female recessed body equipped with a conical fitting part that is close fitted to the conical male projected part of the one ferrule.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ferrule for an optical fiber connector and an optical fiber connector structure employing the ferrule. The present invention relates to a ferrule for a fiber connector and an optical fiber connector structure employing the ferrule.

[0002]

2. Description of the Related Art Optical fibers are widely used in optical communications, optical devices, LAN equipment, various optical communication systems, and the like. At the time of connection, a detachable connection method using an optical fiber connector is adopted. The coupling structure of the ferrule in the conventional optical fiber connector has been configured as shown in a sectional view of FIG. That is, in the figure, 2A and 2B are left and right ferrules, 3A and 3B are left and right flanged cylinders, and optical fiber insertion holes 1a formed in the ferrules 2A and 2B.
1b and optical fiber introduction hole 1 formed in flanged cylinder 3
c and 1d are connected along the optical axis. The outer peripheral portion near the joint between the ferrules 2A and 2B is protected by the split sleeve 4. The optical fibers 1 and 1 'are inserted into the optical fiber insertion holes 1a and 1b of the ferrules 2A and 2B through the optical fiber introduction holes 1c and 1d of the flanged cylinders 3A and 3B.
It has been inserted until.

In order to connect optical fibers with each other using an optical fiber connector, in order to reduce the reflection loss at the connecting portion, the ends of the optical fibers are connected to each other, so-called physical contact (hereinafter, referred to as PC) connection. Has been done. For PC connection, the end face of the ferrule is polished to a convex spherical surface or oblique convex spherical surface at the same time as the optical fiber tip with the optical fiber loaded in the ferrule, or a flat surface or oblique flat surface is polished. However, in the case of a conventional ferrule such as zirconia or glass, there is a problem that such processing cannot be easily performed. Conventionally, optical communication fiber cables have a misalignment of several μm at their connection.
m, it is necessary to attach a connector to the end of the optical fiber, grind both end faces, and connect the ends of the connection fibers by resilient butting to each other. There was a problem that the accuracy of the fiber connection was not improved due to inaccuracy.

Further, ferrules are manufactured by injection molding a raw material obtained by mixing ceramic particles such as zirconia and alumina, stainless steel or other metal particles with an appropriate binder into a predetermined shape, and sintering the material. Therefore, the flowability of the molding material is low, and it has been difficult to fill the molding material to the end face during injection molding.
Therefore, conventionally, injection molding has been performed with an outer diameter larger than the outer diameter as the ferrule, and the outer diameter has been polished after sintering the molded article to finish the ferrule to a predetermined diameter. In the above-mentioned molding method, the obtained fired body is slightly shrunk and deformed by firing, and its inner diameter is shifted from a desired dimension. For this reason, polishing of the cylindrical through-hole on the fired body using the diamond polishing body was an indispensable treatment. However, this polishing is a very labor-intensive and requires skill because the fired body is ceramic and hard, and has caused a decrease in productivity. Moreover, it is not easy to make the inner diameter of the inner hole of the fired body in the axial direction completely uniform even if polishing is performed because the degree of attachment of the diamond to the linear polishing body is not uniform. In addition, there is a problem in that equipment costs increase due to consumption of expensive diamond polishing bodies.
Also, to perform injection molding or extrusion molding as described above,
Expensive dedicated molding machines and molds are required. In particular, since the extremely hard zirconia powder causes significant wear of the molding machine and the mold, their life is short. Although hard materials can be used for the molding machine and the mold surface, the production cost of these special molding machines and molds becomes extremely high. Further, since the firing is performed at a high temperature of about 1200 ° C. in the firing step, energy costs are increased and energy resources are wasted. Furthermore, in the production of the ferrule of the prior art, it was almost impossible to produce a linear hole having a high roundness of 8 mm or more and an inner diameter of 125 μm or less.

[0005]

Means for Solving the Problems The present invention has been made to solve such a problem, and it is an object of the present invention to provide a ferrule capable of easily and reliably connecting optical fiber ends at a connecting portion thereof, and manufacturing the ferrule. An object of the present invention is to provide an optical fiber connector structure employing the same ferrule. That is, an optical fiber connector ferrule having the following configuration and an optical fiber connector structure employing the same ferrule. (1) In a ferrule for an optical fiber connector comprising a ferrule on one side having an optical fiber insertion hole in an optical fiber connector portion and a ferrule on the other side disposed opposite to the same ferrule on the same axis, The front part of the ferrule was a male conical convex body, and the front part of the other ferrule was provided with a conical fitting part for closely receiving the male conical convex body on the one side. A ferrule for an optical fiber connector, comprising a female concave body. (2) In the ferrule for an optical fiber connector, the ferrule on one side having an optical fiber insertion hole in the optical fiber connector portion and the ferrule on the other side disposed opposite to the same ferrule on the same axis. The front part of the ferrule was a male conical convex body, and the front part of the other ferrule was provided with a conical fitting part for closely receiving the male conical convex body on the one side. The base of the conical male convex body is composed of a female concave body, and the base of the conical male convex body is connected to the edge of the annular step formed by reducing the diameter in the radial direction of the ferrule. The ferrule for an optical fiber connector, wherein a base of the mold concave body is connected to an edge of an annular step portion formed by reducing the diameter in the radial direction at the open end of the ferrule. (3) The optical fiber connector according to (1) or (2), wherein the conical male convex of the one ferrule has a depression angle of inclination of 20 to 80 °. Ferrule. (4) The optical fiber connector according to (1) or (2), wherein the conical male convex body of the one ferrule has a conical depression angle of 30 to 60 °. Ferrule.

(5) The ferrule for an optical fiber connector is made of metal.
The ferrule for an optical fiber connector according to any one of (4). (6) The above (1) to (5), wherein the ferrule for an optical fiber connector is made of a nickel alloy.
The ferrule for an optical fiber connector according to any one of the above. (7) The ferrule for an optical fiber connector is made of stainless steel.
The ferrule for an optical fiber connector according to any one of (6). (8) The ferrule for an optical fiber connector is manufactured by an electroforming method.
The ferrule for an optical fiber connector according to any one of (1) to (7). (9) One ferrule having an optical fiber insertion hole, the other ferrule disposed opposite to the same ferrule on the same axis, a protective sleeve covering these ferrules, and a base end of these ferrules In an optical fiber connector structure comprising a fitted cylindrical body with a flange having an optical fiber conducting hole, the ferrule is a male convex body having a conical front part on one side of the ferrule, and a ferrule on the other side. An optical fiber connector structure, wherein a front part of the ferrule is constituted by a female concave body having a conical fitting portion for closely receiving the one conical male convex body on one side. . (10) The ferrule for an optical fiber connector is as described in (2) above.
(8) The optical fiber connector structure according to the above (9), wherein the optical fiber connector structure is any one of the above (9).

[0007]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a ferrule according to the present invention (a), an explanatory perspective view of the ferrule (b), and a front view (c) showing a conical inclination angle of a front part of the ferrule.
It is. FIG. 2 is a sectional view (a) and an explanatory perspective view (b) of the ferrule shown in FIG. 1 in which an annular step is provided at the edge of the conical male convex body and female concave body. It is. FIG. 3 is a sectional view showing a state in which the ferrule is protected by a sleeve. FIG. 4 is a cross-sectional view of a ferrule coupling structure in the optical fiber connector of the present invention. FIG. 5 is an explanatory view of a process for manufacturing the ferrule of the present invention.
(A) Drawing is a manufacturing explanatory drawing of a conical female concave body, (b) is a manufacturing explanatory drawing of a conical male convex body. (C) Figures are a front view and a perspective view of a cutting tool suitable for producing a conical female concave body having an annular step.

[0008] The coupling structure of the ferrule in the optical fiber connector of the present invention is configured as shown in the sectional view of FIG. That is, in the figure, reference numerals 2a and 2b denote left and right ferrules (preferably made of electroformed nickel alloy), 3A and 3B.
B is a cylinder body with left and right flanges, and has ferrules 2a and 2b.
b, and optical fiber introduction holes 1c, 1d formed in flanged cylinders 3A, 3B.
Are connected along the optical axis. Also, ferrule 2a,
The outer peripheral portion near the joint 2b is protected by the split sleeve 4. Here, the front portions 2a 'of the ferrules 2a and 2b,
2b 'is a conical male convex and a conical female concave. The optical fibers 1, 1 'are inserted through the optical fiber introduction holes 1c, 1d of the flanged cylinders 3A, 3B to the optical fiber insertion holes 1a, 1b of the ferrules 2a, 2b.

The flanged cylinders 3A and 3B are usually metal cylinders, and have a rectangular flange 3
a, 3b are formed. This square flange 3a, 3
A ferrule fitting portion having an inner diameter corresponding to the outer diameter of the ferrules 2a and 2b is formed at the center of the ferrules 2a and 2b, and the distal ends of the flanged cylinders 3A and 3B are located outside the base ends of the ferrules 2a and 2b. The ferrules 2a and 2b are fitted together with the flanged cylinders 3A and 3B along the optical axis.
That is, an optical fiber introduction hole communicating with the ferrule fitting portion is formed along the central axis (optical axis) of the cylindrical portion of the flanged cylindrical bodies 3A and 3B. As a result, the optical fiber insertion holes 1a and 1b of the ferrules 2a and 2b fitted with the ferrule fitting portions communicate with the optical fiber introduction holes 1c and 1d. Incidentally, it is preferable that the ferrule in the present invention is formed by an electroforming method. The production of a ferrule by the electroforming method, which was previously developed by the present inventor, is to rotate an electrode thin wire stretched in a nickel ion-based electroforming solution and deposit a nickel-based metal on the surface of the thin wire. This is performed by forming a nickel-based metal thin tube for a ferrule on the electrode thin wire. To change the hardness of the ferrule, for example, by changing the composition of the electroforming solution at the stage of depositing a nickel-based metal (nickel alloy) by the electroforming method, the alloy composition of the inside and the surface layer is changed. Alternatively, the surface layer can be hardened by exposing the nickel-based electroformed thin tube to a high-temperature nitrogen gas atmosphere to perform a nitriding treatment. It is to be noted that the hardness of the male convex body surface layer is higher than that of the conical female concave body surface layer, that is, the hardness of the female concave body surface layer is lower and the hardness of the male convex body surface layer is higher. It is preferable to increase the ratio and to combine them, since the bonding state as a physical contact is stable. Also,
Such a combination structure is suitable for use in a high vibration environment without loosening.

Next, the forming work of the male convex body and the female concave body of the conical shape of the ferrule of the present invention can be performed, for example, as shown in FIG. (A) is a diagram for explaining the production of a female concave body, which is provided with a cutter blade tool 5 made of diamond single crystal (the tool tool has a blade portion 5a that gradually narrows from the tip of a horizontal back portion 5b). The tip is pressed horizontally toward the end hole 1b of the rotating ferrule 2b. (B) is a diagram for explaining the manufacture of the male convex body, and shows a cutter bite 5 made of diamond single crystal.
(The cutting tool is provided with a blade portion 5a that gradually narrows from the tip of the horizontal back portion 5b.) The tip is pressed toward the outer peripheral edge of the rotating ferrule. As described above, the female concave body and the male convex body can be easily and reliably formed at the front part of the ferrule. FIG. 4C is a side view and a perspective view of an example of a cutting tool for manufacturing a female concave body having annular step portions 22a and 22b, and illustrates an isosceles triangular blade portion 50 made of diamond single crystal. It comprises a ring-shaped step-forming pressing tool 51 fixed to the base. The stepped ferrule shown in FIG. 2 can be manufactured by pressing the cutting tool shown in FIG. 2C toward the end of the ferrule as shown in FIG.

The above is a description of the manufacture of the ferrule. In assembling the optical fiber connector structure, first, the ferrules 2a and 2b are inserted into the split sleeve 4 from the left and right. Then, the front part 2 of the ferrule 2a
a ′, the conical male convex portion automatically searches for the same axis line with the conical female concave portion of the front portion 2b ′ of the ferrule 2b with a guide action, and abuts the same. It is inserted accurately, smoothly and easily.

The front surface 2a 'of the ferrule 2a has a conical male convex surface and the front surface 2a of the ferrule 2b.
It is preferable that both the inner surfaces of the conical female concave body b ′ are mirror surfaces. Since they are mirror surfaces, even if light leaks from the tip of 2a ', the leaked light is condensed to the central portion, and the light is sufficiently transmitted.

[0013]

As described above, according to the present invention, it is possible to easily and surely join the optical fiber ends at the joint. That is, the conical male convex body at the front of the one ferrule automatically searches for the same axis with the guiding action of the conical female concave at the front of the other ferrule. It can be inserted accurately, smoothly and easily as if it were in contact. If a ferrule manufactured by electroforming is used, the length is 8 mm or more and the inner diameter is 12 mm.
It is possible to provide a ferrule having the shape of the present invention having linear pores having a high circularity of 5 μm or less.

[Brief description of the drawings]

1A is a sectional view of a ferrule according to the present invention, FIG. 1B is a perspective view of the ferrule, and FIG. 1C is a front view showing a conical inclination angle of a front part of the ferrule.

FIGS. 2A and 2B are a cross-sectional view and a perspective view, respectively, of a ferrule shown in FIG.

FIG. 3 is a cross-sectional view of a state in which a ferrule is protected by a sleeve.

FIG. 4 is a cross-sectional view of a coupling structure of a ferrule in the optical fiber connector of the present invention.

FIG. 5 is an explanatory view of a forming work of a ferrule of the present invention.

FIG. 6 is a cross-sectional view of a ferrule coupling structure in a conventional optical fiber connector.

[Explanation of symbols]

 1, 1 ': optical fiber, 1a, 1b: optical fiber insertion hole, 1c, 1d: optical fiber introduction hole, 2a, 2b: ferrule, 2a': conical male convex body, 2b ': conical Female concave, 2A, 2B: ferrule, 3a, 3b: flange, 3A, 3B: flanged cylinder, 4: split sleeve, 5: bite, 5a: blade, 5b: horizontal back, 50: blade 51: pressing tool,

Claims (10)

[Claims] 1. A ferrule for an optical fiber connector comprising: a ferrule on one side having an optical fiber insertion hole in an optical fiber connector section; and a ferrule on the other side disposed opposite to the same ferrule on the same axis. The front part of the ferrule on the side is a conical male convex body, and the front part of the ferrule on the other side has a conical fitting part for receiving the conical male convex body on one side closely. A ferrule for an optical fiber connector, comprising a female concave body provided with the ferrule. 2. A ferrule for an optical fiber connector comprising: a ferrule on one side having an optical fiber insertion hole in an optical fiber connector section; and a ferrule on the other side disposed opposite to the same ferrule on the same axis. The front part of the ferrule on the side is a conical male convex body, and the front part of the ferrule on the other side has a conical fitting part for receiving the conical male convex body on one side closely. The base of the conical male convex body is composed of a female concave body provided with a conical male convex body, and the base of the ferrule is connected to the edge of the annular step formed by reducing the diameter in the radial direction. Wherein the base of the female concave body is connected to the edge of an annular step formed by reducing the diameter in the radial direction at the open end of the ferrule. 3. The ferrule for an optical fiber connector according to claim 1, wherein the conical male convex body of the one ferrule has a conical depression angle of 20 to 80 °. . 4. A ferrule for an optical fiber connector according to claim 1, wherein the conical male convex body of one of the ferrules has a conical depression angle of 30 to 60 °. . 5. The ferrule for an optical fiber connector according to claim 1, wherein the ferrule for an optical fiber connector is made of metal. 6. The ferrule for an optical fiber connector is made of a nickel alloy.
The ferrule for an optical fiber connector according to any one of the above. 7. The ferrule for an optical fiber connector according to claim 1, wherein the ferrule for an optical fiber connector is made of stainless steel. 8. The ferrule for an optical fiber connector according to claim 1, wherein the ferrule for an optical fiber connector is manufactured by an electroforming method. 9. A ferrule on one side having an optical fiber insertion hole, a ferrule on the other side disposed opposite the same ferrule on the same axis, a protective sleeve for covering the ferrule, and a base end of the ferrule In the optical fiber connector structure comprising a cylindrical body with a flange having an optical fiber conducting hole fitted on the side thereof, the ferrule is a male convex body having a conical front part on one side of the ferrule, and the other side. An optical fiber connector comprising a female concave body having a conical fitting portion for closely receiving the conical male convex body on the one side. Structure. 10. The optical fiber connector structure according to claim 9, wherein the ferrule for an optical fiber connector is the ferrule according to any one of claims 2 to 8.