JP2006011255A - Optical connector ferrule and optical connector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an optical connector ferrule and an optical connector with which increase in yield and in productivity in manufacturing the optical connector can be realized. <P>SOLUTION: In an optical connector ferrule 23 in which fiber holes 26 in which optical fibers 11 are threaded are passed through and formed along the longitudinal direction and a front end face 27 in which fiber holes 26 are opened is formed on a slope having an angle larger than the total reflection critical angle of rays of light propagating in the optical fibers, a thin transparent board 31 which covers the openings of the fiber holes 26 is stuck on the front end face 27. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical connector ferrule having a fiber hole through which an optical fiber is inserted, and an optical connector using the optical connector ferrule, and more particularly to improve yield and productivity when manufacturing an optical connector. It is about improvement.

FIG. 4 is a perspective view of a conventional multi-fiber optical connector.
The multi-fiber optical connector 1 shown here has a structure in which a multi-fiber optical fiber tape 5 is connected to an optical connector ferrule 3.
The optical connector ferrule 3 is an integrally molded product formed by resin injection molding. A plurality of fiber holes 6 through which an optical fiber is inserted are formed along the front-rear direction, and a plurality of fiber holes 6 are opened. The front end surface 7 is formed on an inclined surface having an angle θ larger than the total reflection critical angle of the propagation light in the optical fiber (see, for example, Patent Document 1).

The plurality of fiber holes 6 are juxtaposed at regular intervals in the width direction of the connector. Guide holes 9 through which guide pins are inserted are formed through both sides of the plurality of fiber holes 6.
The guide pin is inserted into and fixed to one of the optical connector ferrules of the two optical connectors that are connected in abutment. The guide pins provided to project from one optical connector are joined together so that they are inserted into the guide holes 9 of the other optical connector, and the optical fiber core ends can be optically communicated by this guide pin. Are positioned and butted together.

The optical fiber tape 5 is formed by joining and integrating a plurality of (four in the figure) optical fibers 11 in a tape shape with an outer coating 13.
At the tip of the optical fiber tape 5 connected to the optical connector ferrule 3, the external coating 13 is previously peeled off over a predetermined length so that the optical fiber 11 is exposed, and each exposed optical fiber 11 is inserted into the fiber hole 6. Is done.
The base end side of the plurality of fiber holes 6 communicates with a tape housing space 14 having a rectangular cross section through which the optical fiber tape 5 can be inserted with the outer coating 13.

By the way, the multi-fiber optical connector 1 having the above configuration has been manufactured by the following steps.
First, as shown in FIGS. 5 (a) and 5 (b), the optical fiber 11 exposed by peeling off the outer coating 13 of the optical fiber tape 5 has a front end surface 11 a having a front end surface before polishing the optical connector ferrule 3. The fiber hole 6 is inserted until it protrudes slightly from 7a.
Then, after the optical fiber 11 inserted into each fiber hole 6 is fixed to the optical connector ferrule 3 with the adhesive 15 including the front end surface 11a, the front end surface before ferrule polishing to the finishing position indicated by the alternate long and short dash line 17 in the figure 7a and the front end portion of the optical fiber 11 are polished at a predetermined inclination angle to form a regular front end face 7 that abuts against the counterpart optical connector ferrule.

JP-A-4-336509

However, in the conventional manufacturing method in which the front end surface 7a of the optical connector ferrule 3 is polished after the optical fiber 11 is inserted and fixed to the optical connector ferrule 3, an excessive grinding force acts on the optical fiber 11 during polishing. There is a possibility that the defect 16 of the optical fiber 11 may occur, and the defect 16 of the optical fiber 11 causes a problem that the product yield decreases.
In addition, in order to keep the occurrence of the defects 16 in the optical fiber 11 to a minimum, a careful operation is required for polishing the front end surface 7a, which may cause a reduction in productivity.

  The objective of this invention is providing the optical connector ferrule and optical connector which can implement | achieve the improvement of the yield at the time of optical connector manufacture, and the improvement of productivity.

  In order to achieve the above object, an optical connector ferrule according to claim 1 of the present invention is an optical connector ferrule in which a fiber hole through which an optical fiber is inserted is formed, and an opening portion of the fiber hole is formed on an end surface. A transparent plate is provided.

  An optical connector ferrule according to a second aspect of the present invention is the optical connector ferrule according to the first aspect, wherein the end surface has an inclination angle of 10 ° or less with respect to a plane perpendicular to the axial direction of the fiber hole. It may be characterized by being inclined.

  An optical connector ferrule according to a third aspect of the present invention is the optical connector ferrule according to the first or second aspect, wherein an air vent groove for communicating the opening of the fiber hole to the outside is formed on the end face. It should be characterized by that.

  An optical connector ferrule according to a fourth aspect of the present invention is the optical connector ferrule according to the third aspect, wherein the optical connector ferrule has a multi-core structure in which a plurality of the fiber holes are provided at a predetermined interval, and opens at the end face. The groove may be formed across the end face so that the openings of the fiber holes communicate with each other.

  The optical connector ferrule according to claim 5 according to the present invention is the optical connector ferrule according to any one of claims 1 to 4, wherein the transparent plate is 90% or more of the propagation light in the optical fiber. It may be characterized by being formed of a substance having transmittance.

  In order to achieve the above object, an optical connector according to a sixth aspect of the present invention uses the optical connector ferrule according to any one of the first to fifth aspects, wherein the fiber hole is formed in the fiber hole. An optical fiber having a distal end surface cut substantially perpendicular to the optical axis is inserted and fixed.

  An optical connector according to a seventh aspect of the present invention is the optical connector according to the sixth aspect, wherein the optical fiber inserted into the fiber hole has a distal end surface close to the transparent plate, The gap between the transparent plate and the transparent plate may be filled with an adhesive whose refractive index is matched with the core refractive index of the optical fiber.

  An optical connector according to an eighth aspect of the present invention is the optical connector according to the sixth or seventh aspect, wherein the optical fiber inserted and fixed in the fiber hole is a multimode optical fiber. Good.

According to the optical connector ferrule and the optical connector of the present invention, the end face of the optical connector ferrule is polished and finished, and then a transparent plate is attached. Therefore, when connecting an optical fiber to the optical connector ferrule, the opening to the end face of the fiber hole into which the optical fiber is inserted is already covered with a transparent plate, and the tip of the optical fiber inserted into the fiber hole However, it does not protrude from the end face of the optical connector ferrule and is not polished.
Therefore, the optical fiber inserted into and fixed to the optical connector ferrule is not damaged due to the polishing process, and the yield at the time of manufacturing the optical connector can be improved. Further, since the end face of the optical connector ferrule can be polished by itself before connecting the optical fiber, the polishing process can be facilitated and the productivity can be improved.

DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of an optical connector ferrule and an optical connector according to the present invention will be described in detail with reference to the drawings.
In the present embodiment, a multi-mode optical fiber is used as the optical fiber, and the case where the multi-mode optical fiber is applied to an optical connector ferrule with a resin coating will be described.
FIG. 1 is a perspective view of a first embodiment of an optical connector according to the present invention.

  The optical connector 21 according to the first embodiment is a multi-fiber optical connector formed by connecting a multi-fiber optical fiber tape 5 to an optical connector ferrule 23.

  The optical connector ferrule 23 is an integrally molded product formed by resin injection molding, and a plurality of fiber holes 26 through which the optical fiber 12 that is separated from the optical fiber tape 5 by a single core (with external coating) is inserted in the front-rear direction. And a front end surface 27 through which a plurality of fiber holes 26 open is formed as an inclined surface having an angle α larger than the total reflection critical angle of the propagation light in the optical fiber.

The plurality of fiber holes 26 are juxtaposed at regular intervals in the width direction of the connector.
The plurality of fiber holes 26 are arranged in a line at the center of the front end surface 27, and guide holes 29 into which guide pins are inserted are formed through both sides of the plurality of fiber holes 26.

  The guide pin is inserted and fixed in the guide hole 29 of one of the two optical connectors to be connected in abutment. Then, the guide pins provided so as to protrude from one optical connector are joined together so as to be inserted into the guide hole 29 of the other optical connector, and the ends of the optical fiber cores are optically connected by this guide pin. Positioned and butted so that they can communicate.

The optical fiber tape 5 is formed by joining a plurality of (four in the figure) optical fibers 12 together in a tape shape by an outer coating 13. Each optical fiber 12 is a multimode optical fiber.
At the tip of the optical fiber tape 5 connected to the optical connector ferrule 23, the outer coating 13 is cut in advance over a predetermined length so that each optical fiber 12 is in a single-core separated state. It is inserted into the fiber hole 26.
The base end sides of the plurality of fiber holes 26 communicate with the tape housing space 14 having a rectangular cross section through which the optical fiber tape 5 can be inserted with the outer coating 13.

  Specifically, the inclination angle α of the front end face 27 of the optical connector ferrule 23 is set to an inclination angle of 8 ° with respect to a vertical plane orthogonal to the axial direction of the fiber hole 26.

The optical connector ferrule 23 of this embodiment covers the opening of each fiber hole 26 on the front end surface 27 after the front end surface 27 is polished to a predetermined inclination angle and before the optical fiber tape 5 is connected. A thin transparent plate 31 is attached.
The thin transparent plate 31 is made of quartz glass having a transmittance of 90% or more with respect to the propagation light in the optical fiber.
However, the material is not limited to quartz glass as long as it has the above transmittance. Thin plate materials made of other materials such as plastic and Pyrex (registered trademark) glass can also be used.

  The thin transparent plate 31 has a thickness of about 100 μm or less. This plate thickness is defined so that the transmitted light passing through the thin transparent plate 31 in combination with the transmittance propagates well in the optical fiber of the counterpart optical connector ferrule, and the mode field diameter (MFD). Is a normal multimode optical fiber having a thickness of 50 μm, and the present inventors have measured the distance between the optical fibers to be 200 to 300 μm (100 to 150 μm per one-side ferrule), that is, the thickness of the thin transparent plate 31 as described above. As shown in the figure, it was confirmed that when the thickness is about 100 μm or less, the transmission loss can be reduced to 0.05 dB or less and no problem is caused.

The front end surface 27 of the optical connector ferrule 23 of the present embodiment is formed with an air vent groove 33 that allows the openings of the plurality of fiber holes 26 to communicate with the outside through the guide holes 29.
The groove 33 is a groove having a semicircular cross-sectional shape, and is formed across the front end face 27 in the width direction so that the openings of the fiber holes 26 opened in the front end face 27 communicate with each other. The opening of each fiber hole 26 is communicated with the guide hole 29.
When the optical fiber 12 is inserted into the fiber hole 26, the groove 33 removes air remaining in the fiber hole 26 and facilitates the insertion of the optical fiber 12.

Connection of the optical fiber tape 5 to the optical connector ferrule 23 is performed according to the following procedure.
As shown in FIG. 2A, the optical connector ferrule 23 is in a state in which a thin transparent plate 31 is adhered to the front end surface 27 thereof.
Then, the optical fiber tape 5 cuts the outer coating 13 in the range of a predetermined length at the tip, and keeps the optical fiber 11 to be inserted into the fiber hole 26 in a single-core separated state.
As shown in FIG. 2B, the end surface 12a of the optical fiber 12 separated from the single core is subjected to end surface processing in a form cut at a substantially right angle to the optical axis Ax.

Then, each optical fiber 12 that has been subjected to the end face treatment is inserted into the fiber hole 26 until the distal end face 12a thereof approaches or comes into contact with the inner face of the thin transparent plate 31.
Before inserting the optical fiber 12 into the fiber hole 26, the fiber hole 26 on the thin transparent plate 31 side is filled with an adhesive (not shown) whose refractive index is matched with the core refractive index of the optical fiber 12. Keep it.
As a result, when the optical fiber 12 is inserted into the fiber hole 26 until the front end surface 12a is close to the inner surface of the thin transparent plate 31, the gap between the front end surface 12a of the optical fiber 12 and the thin transparent plate 31 becomes the fiber hole. The light transmission characteristics are not hindered by the presence of the air gap.

In the optical connector 21 described above, the front end surface 27 of the optical connector ferrule 23 is polished and finished in advance at a predetermined inclination angle, and then a thin transparent plate 31 is attached. Accordingly, when the optical fiber 12 is connected to the optical connector ferrule 23, the opening of the front end surface 27 of the fiber hole 26 is already covered by the thin transparent plate 31, and the optical fiber 12 inserted into the fiber hole 26 is inserted. The front end surface 12a does not protrude from the front end surface 27 of the optical connector ferrule 23 and is not subjected to polishing.
Therefore, the optical fiber inserted into and fixed to the optical connector ferrule 23 is not damaged due to a defect due to the polishing process, and the yield at the time of manufacturing the optical connector 21 can be improved.
Further, since the front end face 27 can be polished by the optical connector ferrule 23 alone before the optical fiber 12 is connected, the polishing process is facilitated and the productivity can be improved. .

  Further, the connection between the optical connector ferrule 23 and the optical connector ferrule of the mating connector is in a state where the thin transparent plate 31 is in contact, and the front end surface 27 of the optical connector ferrule 23 is not in direct contact with the mating connector. Therefore, if the surface of the thin transparent plate 31 is sufficiently smooth, it is possible to reduce the polishing accuracy of the front end face 27, thereby reducing workability and processing cost.

  In the first embodiment described above, the coated optical fiber 12 is inserted into the fiber hole 26. However, the bare fiber with the outer coating of the optical fiber tape 5 peeled off may be applied to the optical connector ferrule 23. it can.

  In the first embodiment described above, the thin transparent plate 31 protrudes from the front end surface 27 of the optical connector ferrule 23. However, as shown in FIG. 3, the surface of the thin transparent plate 31 is the front end surface. A counterbore 35 may be formed on the front end surface 27 so as to be flush with the surface 27.

1 is a perspective view of a first embodiment of an optical connector according to the present invention. FIGS. 2A and 2B are explanatory views of a manufacturing process of the optical connector shown in FIG. 1, in which FIG. 1A is a longitudinal sectional view of a state before an optical fiber is connected to an optical connector ferrule, and FIG. It is a longitudinal cross-sectional view of this state. It is a longitudinal cross-sectional view of 2nd Embodiment of the optical connector which concerns on this invention. It is a perspective view of the conventional optical connector. It is explanatory drawing of the manufacturing process of the optical connector shown in FIG. 4, (a) is a top view, (b) is sectional drawing which follows the AA line of (a).

Explanation of symbols

5 Optical Fiber Tape 11 Optical Fiber 13 Outer Cover 21 Optical Connector 23 Optical Connector Ferrule 26 Fiber Hole 27 Front End Surface 29 Guide Hole 31 Thin Transparent Plate 33 Groove

Claims (8)

In the optical connector ferrule in which the fiber hole through which the optical fiber is inserted is formed,
An optical connector ferrule comprising a transparent plate covering an opening of the fiber hole on an end surface.   2. The optical connector ferrule according to claim 1, wherein the end face is inclined at an inclination angle of 10 ° or less with respect to a plane orthogonal to the axial direction of the fiber hole.   3. The optical connector ferrule according to claim 1, wherein an air vent groove that allows the opening of the fiber hole to communicate with the outside is formed on the end face. 4.   The fiber hole has a multi-core structure in which a plurality of fiber holes are provided at a predetermined interval, and the groove is formed across the end face so that the openings of the fiber holes that open to the end face communicate with each other. The optical connector ferrule according to claim 3.   5. The optical connector ferrule according to claim 1, wherein the transparent plate is made of a material having a transmittance of 90% or more with respect to the light propagating in the optical fiber.   The optical connector ferrule according to any one of claims 1 to 5 is used, and an optical fiber having a tip surface cut substantially perpendicular to the optical axis is inserted and fixed in the fiber hole. An optical connector characterized by that.   The optical fiber inserted into the fiber hole has a front end face close to the transparent plate, and the refractive index matches the core refractive index of the optical fiber in the gap between the front end surface of the optical fiber and the transparent plate. The optical connector according to claim 6, wherein the optical adhesive is filled. The optical connector according to claim 6 or 7, wherein the optical fiber inserted and fixed in the fiber hole is a multimode optical fiber.

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