JP4698376B2 - Multi-fiber optical connector - Google Patents

Description

The present invention relates to a multi- fiber optical connector.

Conventionally, if there is an air layer in the optical connector connection, light loss due to Fresnel reflection occurs, but as a means to reduce this light loss, the tip of the ferrule is polished flat when the connector is attached, and between the ferrule ends when connecting the connector. There is a method in which a refractive index matching agent having a refractive index comparable to that of an optical fiber core is interposed.
Also, if the optical fiber connector is a single-fiber optical connector, the ferrule tip is polished into a spherical shape, and if it is a multi-fiber optical connector such as an MT connector (equivalent to JIS C 5981 F12 type multi-fiber optical fiber connector) There is a method of performing PC polishing and making a PC (Physical Contact) connection.

Further, as a method other than the above general method, for example, there is a method of Patent Document 1. In this method, a windowed mold is formed on the end face of the ferrule, and an uncured resin having the same refractive index as that of the optical fiber and having elasticity after curing is applied to the windowed mold and cured. There is one in which an antireflection film having elasticity is formed on the end face of the ferrule by removing the mold with window later.
JP-A-2-308207

The method using the refractive index matching agent or the PC connection method requires an operation of interposing the refractive index matching agent on the connection end face when connecting the connector, or an operation of polishing the end face with high accuracy, and the work is complicated. There is a drawback of poor workability.
Further, the method using a refractive index matching agent further has a problem that it is difficult to manage the refractive index matching agent held between the end faces because the refractive index matching agent is gel or liquid. Further, the refractive index matching agent may be volatilized depending on the temperature, and may be altered by moisture absorption.

  Moreover, the method of patent document 1 has the fault that the process which forms a window-form frame on the end surface of a ferrule is complicated.

The present invention has been made to solve the above-mentioned conventional drawbacks, and provides a multi- fiber optical connector that does not require a refractive index matching agent filling operation or an end surface polishing operation at the time of connector connection and is easy to manufacture. Objective.

The invention of claim 1 which solves the above-mentioned problem is a multi-fiber optical connector in which guide pin holes are formed on both sides in the arrangement direction of a plurality of optical fiber holes opened in the ferrule tip surface.
Wherein both sides of the guide pin hole in one corner-shaped recess in which a plurality of optical fiber holes are opened at once to the recess bottom surface at a position sandwiched the ferrule tip end face is formed, the light transmitted into the recess The light-transmitting elastic material is formed in such a manner that the elastic elastic material protrudes from the ferrule tip surface over the entire recess, and the tip surface of the optical fiber inserted into each optical fiber hole is retracted from the ferrule tip surface. It is characterized by each contacting.

According to a second aspect of the present invention, in the multi- fiber optical connector according to the first aspect, the front surface of the light-transmitting elastic material formed in the recess of the ferrule has a cylindrical surface shape.

A third aspect of the present invention is the multi-fiber optical connector according to the first or second aspect , wherein the light-transmitting elastic material is insert-molded or overmolded with respect to the ferrule.

According to the multi-fiber optical connector of the present invention, the light-transmitting elastic material is elastically deformed, so that the connector connection without an air layer is formed between the mating connection end surface. Therefore, light loss due to reflection at the connector connecting portion can be reduced without using a refractive index matching agent or without performing PC polishing.
In addition, the work of interposing a refractive index matching agent on the connection end face when the connector is connected, or the work of polishing the ferrule end face with high precision when the connector is attached are unnecessary, and the workability of the connector connection is improved. In addition, since man-hours can be reduced, costs can be reduced.
In addition, it is not a gel-like or liquid material such as a refractive index matching agent, but is an elastic material. Therefore, there are drawbacks of the refractive index matching agent, that is, difficulty in managing the ferrule end faces, volatilization, and alteration due to moisture absorption. Etc. are useless.
Further, since the recess of the corner shaped ferrule tip is mold for forming a light-transmitting elastic material, unlike the conventional method of forming a window with formwork on the end face of the ferrule, easy formation of the light-transmitting elastic material It is.

Hereinafter, a multi-core optical connector embodying the present invention will be described with reference to the drawings.

1 to 3 show a single-core optical connector as a reference example of the present invention . This single-core optical connector 1 has a basic structure in which a cylindrical ferrule 2 made of zirconia or the like having a single optical fiber hole 2a is integrally fixed to a ferrule holder 3 made of stainless steel or the like. The ferrule holder 3 has a covering portion receiving hole 3a for receiving the covering portion 4b of the optical fiber core wire 4, and has a flange portion 3c in which a rotation stop notch 3b is formed.
The distal end surface of the ferrule 2, as shown in FIG. 3, the recess 2b which is opened to the optical fiber hole 2a in the recess bottom surface is formed, FIG. 1 in the recess 2b, as shown in FIG. 2 The light-transmitting elastic material 5 is formed in such a manner that its front surface slightly protrudes from the ferrule tip surface.

  The light-transmitting elastic material 5 is made of a material whose refractive index is close to that of the core of the optical fiber and can be easily elastically deformed. For example, a liquid silicon molded product, polycarbonate, modified polyolefin, etc. can be used. As a molding method, it is possible to mold by insert molding or overmolding by injection molding or LIM molding (liquid injection molding). That is, the recess 2b of the ferrule 2 is formed as a mold. In the case of a liquid silicon molded product, it is performed by LIM molding. Thus, since the recess 2b at the tip of the ferrule serves as a mold for forming the light-transmitting elastic material, it is easy to form the light-transmitting elastic material.

When the optical fiber (bare fiber) 4a of the optical fiber core wire 4 is inserted into the optical fiber hole 2a of the ferrule 2 of the single-fiber optical connector 1 and pushed into the back, as shown in FIG. 2, the tip surface of the optical fiber 4a Are closely attached to the light-transmitting elastic material 5 at a position retracted from the ferrule tip surface.
In such a connector connection in which the single-core optical connectors 1 are brought into contact with each other, the optical fiber 4a and the light-transmitting elastic material 5 are easily in close contact with each other by the elastic deformation of the light-transmitting elastic material. An air layer is not formed, and the light-transmitting elastic members 5 of the single-fiber optical connectors 1 are in direct contact with each other in a state of being elastically deformed, so that an air layer may be generated between the light-transmitting elastic members 5. Therefore, light loss due to reflection at the connector connecting portion can be reduced.
Easy front of the light-transmitting elastic member 5 is deformed during connection so formed into a spherical shape in the illustrated embodiment, the light-transmitting elastic member 5, it is easy to adhere to the air layer does not occur in the other side .

The front of the above Reference Example in the light-transmitting elastic member 5 was in a spherical shape, but also optically transparent elastic material 5 'is shown in FIG. 4 of Reference Example has a flat front.

5 to 7 show an embodiment of the multi-fiber optical connector of the present invention. The multi-fiber optical connector 11 of this embodiment is a so-called pin fitting positioning type MT connector (corresponding to F12 type multi-fiber optical fiber connector of JIS C 5981), and is generally made of PPS (poniphenylene sulfide) or the like. A rectangular ferrule 12 is provided with a plurality of optical fiber holes 12a in a horizontal row, guide pin holes 12c are provided on both sides thereof, an optical fiber core wire insertion opening 12d and an adhesive filling window 12e are provided, and an adhesive filling window 12e is provided. Has a basic structure in which a guide groove 12f is provided and a flange 12g is provided on the outer periphery of the rear end.
A shallow square recess 12b in which the plurality of optical fiber holes 12a are collectively opened on the bottom surface of the recess is formed at positions sandwiched by the guide pin holes on both sides of the front end surface of the ferrule 12. As shown in FIG. 5, the light-transmitting elastic material 15 is formed in the recess 12b in such a manner that its front surface slightly protrudes from the ferrule tip surface over the entire recess . The front surface of the light transmissive elastic material 15 in the illustrated example has a cylindrical surface shape, but may be a flat surface. As described above , the light-transmitting elastic material 15 is made of a material having a refractive index close to that of the core of the optical fiber and can be easily elastically deformed. For example, a liquid silicon molded product, polycarbonate, modified polyolefin, etc. As the molding method, it can be molded by injection molding, LIM molding (liquid injection molding), an insert mold or an overmold. That is, the recess 12b of the ferrule 12 is molded as a mold. In the case of a liquid silicon molded product, LIM molding is performed. As described above, the recess 12b at the tip of the ferrule serves as a mold for forming the light-transmitting elastic material, so that the light-transmitting elastic material can be easily formed.

When each optical fiber (bare fiber) 14a of the optical fiber ribbon 14 is inserted into the optical fiber hole 12a of the ferrule 12 of the multi-fiber optical connector 11, the tip surface of the optical fiber 14a is as shown in FIG. It closely adheres to the light-transmitting elastic material 15 at a position retracted from the ferrule tip surface. The covering portion 14b of the optical fiber ribbon 14 is covered with a rubber boot 17 that fits into the optical fiber core insertion opening 12d.
In such a connector connection in which the multi-fiber optical connectors 11 are brought into contact with each other, the optical fiber 14a and the light-transmitting elastic material 15 are easily adhered to each other without a gap due to elastic deformation of the light-transmitting elastic material. An air layer is not formed, and the light-transmitting elastic members 15 of the multi-fiber optical connectors 11 are in direct contact with each other in an elastically deformed state, so that an air layer is generated between the light-transmitting elastic members 15. Therefore, light loss due to reflection at the connector connecting portion can be reduced. Note that the other end of the connector connection is not necessarily the multi-fiber optical connector 11 of the present invention.

FIG. 8 shows another embodiment of the multi-fiber optical connector of the present invention. The multi-fiber optical connector 11 ′ of this embodiment is a multi-fiber optical connector having a built-in optical fiber as the multi-fiber optical connector 11 of the embodiment of FIGS. 5 to 7, that is, a short length in advance in the optical fiber hole 12a. The built-in optical fiber 18 is fixed internally. The other points are the same as those of the multi-fiber optical connector 11 shown in FIGS.
In the multi-fiber optical connector 11 ′ of this embodiment, the optical fiber 14 a of the optical fiber ribbon 14 is inserted into the optical fiber hole 12 a and butt-connected to the built-in optical fiber 18. A refractive index matching agent is interposed in the abutting portion, but there are few problems with using the refractive index matching agent in this portion.

9 to 11 show examples applied to mechanical splices as reference examples . Although the external appearance of the mechanical splice 21 shown in FIG. 9 is general, the mechanical splice 21 includes a positioning base 22 having a positioning groove 22a formed in the center in the width direction as shown in FIG. A center lid portion 23 for pressing the vicinity of the connection portion of the optical fiber connected on the top, and a lid portion 24 for pressing the coating portion of each optical fiber on both sides thereof. It has a basic structure having a C-shaped leaf spring 26 that elastically sandwiches 23 and 24. Also, there are wedge member insertion recesses 27 and 28 into which wedge members for opening the lids 23 and 24 are inserted. Then, a recess 22b is formed in the central portion (optical fiber connection position) of the positioning groove 22a of the positioning table 22, and a thin plate-like light-transmitting elastic material 25 is formed in a manner embedded in the recess 22b.
In this mechanical splice 21, the optical fibers 29 and 30 inserted from both sides into the positioning groove 22a are abutted against the light-transmitting elastic member 25 in the center portion without using a refractive index matching agent. 30 can be abutted in such a manner that no air layer is formed between them.

The single-fiber optical connector as a reference example of this invention is shown, (A) is a longitudinal cross-sectional view, (B) is a left side view of (A). It is a principal part enlarged view of the state which inserted and fixed the optical fiber in the optical fiber hole of the ferrule in FIG. It is a perspective view of the ferrule tip part before forming a light-transmitting elastic material in a recess in the above-mentioned single core optical connector. Similarly , it shows the modification about the front shape of a light-transmitting elastic material as a reference example, and is a figure equivalent to FIG. It is a longitudinal cross-sectional view which shows one Example of the multi-fiber optical connector of this invention. FIG. 6 is a perspective view of a ferrule before forming a light-transmitting elastic material in a recess in the multi-fiber optical connector of FIG. 5. It is a longitudinal cross-sectional view of the ferrule of FIG. It is a longitudinal cross-sectional view which shows the other Example of the multi-fiber optical connector of this invention. It is a perspective view of a mechanical splice. As a reference example, illustrates an example of using a light-transmissive elastic material to the mechanical splice is a perspective view of the base member. It is a principal part enlarged plan view of FIG.

11 , 11 'Multi-fiber optical connector 12 Ferrule 12a Optical fiber hole 12b Recess 12c Guide pin hole 12e Adhesive filling window 14 Optical fiber ribbon 14a Optical fiber (bare fiber)
14b covering 15 light-transmissive elastic member 18 built-in optical fiber

Claims (3)

A multi-fiber optical connector in which guide pin holes are formed on both sides in the arrangement direction of a plurality of optical fiber holes opened in a ferrule tip surface,
Wherein both sides of the guide pin hole in one corner-shaped recess in which a plurality of optical fiber holes are opened at once to the recess bottom surface at a position sandwiched the ferrule tip end face is formed, the light transmitted into the recess The light-transmitting elastic material is formed in such a manner that the elastic elastic material protrudes from the ferrule tip surface over the entire recess, and the tip surface of the optical fiber inserted into each optical fiber hole is retracted from the ferrule tip surface. A multi-fiber optical connector, characterized by being in contact with each other.   2. The multi-fiber optical connector according to claim 1, wherein the front surface of the light-transmitting elastic material formed in the recess of the ferrule has a cylindrical surface shape. The multi-fiber optical connector according to claim 1 or 2, wherein the light-transmitting elastic material is insert-molded or over-molded with respect to the ferrule.

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