JPH06313824A - Optical connector - Google Patents

Abstract

PURPOSE:To provide an optical connector enabling positive PC connection even with multiple cores. CONSTITUTION:The end faces of optical fibers are positioned and fixed to the connecting end faces 5 of optical connector ferrules 3, and the connecting end faces 5 are mutually positioned in close contact to connect the optical fibers 4 optically to one another. In such an optical connector 1 having the optical connector ferrules 3 allowing the optical fibers 4 to be fixed as well as having guide pin holes 2, and the optical fibers 4 fixed to the optical connector ferrules 3, at least the connecting end face of the optical connector ferrule 3 is formed of a low hardness member lower in hardness than the optical fiber, and a protruding part 6 protruding from the other part is provided around the optical fiber 4 of the connecting end face 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical connector for connecting an optical fiber.

[0002]

2. Description of the Related Art In an optical connector for connecting an optical fiber, (1) reduction of reflected return light at the connection point (reduction of reflection), and (2) back reflection or scattering due to reflection at the connection point Therefore, it is necessary to reduce the light that does not propagate to the light receiving side (reduction loss).

For this reason, physical contact (PC) coupling (direct contact coupling between end faces of optical fibers) has been studied for single-core connectors. For example, Japanese Patent Laid-Open No. 61-13.
A polishing plate for an optical connector as disclosed in Japanese Patent No. 7107 has been developed.

On the other hand, in a multi-core connector, it is difficult to connect all the cores to a PC. Therefore, conventionally, in order to achieve low reflection, an attempt has been made to obliquely polish and connect the end faces. However, since the reflection loss cannot be eliminated by this method, the optical connectors are currently coupled with each other by interposing an index matching agent having a refractive index substantially the same as that of the core of the optical fiber between the end faces of the optical fiber.

However, in the connection in which the refractive index matching agent is interposed between the end faces of the optical fiber as described above, the refractive index matching agent must be applied without fail, which is disadvantageous in terms of workability and handling. There is also a problem that dust easily mixes between the end faces of the fiber.

Therefore, studies have been made on a coupling method that does not use a refractive index matching agent even in a multi-core connector. Japanese Patent Laid-Open No. 4-34403 discloses a method in which a resin film having a refractive index close to that of the core is provided on the end face of the optical connector and the optical connectors are connected to each other through the resin film.

[0007]

However, in the method of providing the resin film having the refractive index close to that of the core on the end surface of the optical connector as described above, a thin resin film exists on the end surface of the optical connector. It lacks long-term reliability for the coupling operation of the optical connector, and is also disadvantageous in corrosion resistance and coupling strength. Further, if the thickness of the resin film is increased in order to increase the strength of the resin film, there is a problem that it leads to an increase in coupling loss.

Therefore, there is a demand for a technique capable of PC-coupling all cores in a multi-core connector as well as a single core. However, in the multi-core connector, it is difficult to stably project only the optical fiber by controlling the condition of polishing the entire coupling end face after fixing the optical fiber to the ferrule. In particular, the material forming the ferrule contains a filler for stabilizing the ferrule size, and this filler is likely to protrude from the polishing surface. Therefore, only the optical fiber end face is protruded from the polishing surface. Is difficult. Further, even if the end faces of the optical fibers can be projected, the end faces of the respective optical fibers are not oriented in the same direction, and the inclination angle of each end face has a variation of about 0.2 °. Therefore, there is also a problem that the coupling in each optical fiber becomes unstable.

In view of such circumstances, an object of the present invention is to
An object of the present invention is to provide an optical connector that can realize PC coupling with stable and low loss even in a multi-core system.

[0010]

In the optical connector of the present invention which has achieved the above object, the end face of the optical fiber is positioned and fixed to the coupling end face of the optical connector ferrule capable of fixing the optical fiber, and the coupling end faces are positioned and adhered to each other. In the optical connector that optically couples the optical fibers to each other, at least the coupling end face of the optical connector ferrule is configured by a low hardness member having a hardness lower than that of the optical fibers.

[0011]

In the optical connector of the present invention, when the coupling end face is fixed after the optical connector is fixed, the one having a low hardness is easily polished, so that the end face of the optical fiber is slightly projected from the end face of the optical connector ferrule. PC coupling between the fiber end faces is ensured.

[0012]

EXAMPLES The present invention will be described below based on examples.

FIG. 1 shows an example of an optical connector according to the present invention. As shown in the figure, the multi-fiber optical connector 1 includes an optical connector ferrule 3 which has two guide pin holes 2 penetrating in the optical fiber axial direction and which can fix an optical fiber, and an optical connector ferrule 3. The optical fiber 4 is fixed with an adhesive.

Here, the optical connector ferrule 3 is manufactured by transfer molding using an epoxy resin containing no filler, and has a lower hardness than the optical fiber 4. Further, a 4-core tape fiber is used as the optical fiber 4, and an epoxy adhesive containing no filler is used as an adhesive for fixing the optical fiber.

In the optical connector 1, the optical fiber 4 is fixed to the optical connector ferrule 3 by fixing the optical fiber 4 with the tip of the optical fiber 4 protruding from the end face of the optical connector ferrule 4.
And the end face of the optical connector ferrule 3 are polished. Here, three steps of rough polishing (diamond # 2000), medium polishing (diamond lapping film # 5000), and final polishing (polishing with cerium oxide) are performed on the tip of the optical fiber 4 and the end surface of the optical connector ferrule 3. As a result, as shown in FIG. 1, the end face of the optical fiber 4 is projected from the end face of the optical connector ferrule 3 by about 1 μm.

As shown in FIGS. 2A and 2B, such a multi-fiber optical connector 1 has a coupling end face in which a guide pin 6 is inserted into a guide pin hole 2 so that an end face of an optical fiber 4 is positioned and arranged. 5 are abutted against each other, and the pair of multi-fiber optical connectors 1 are optically coupled by being sandwiched by grips 9 having plate springs 8 provided at both ends of a plate member 7. That is, since the coupling end faces 5 are pressed in a state in which they are in close contact with each other, the end faces of the optical fiber 4 slightly protruding from the end faces of the optical connector ferrule 3 are reliably optically coupled.

Further, in general, when the optical connectors are coupled to each other, the coupling end faces are brought into close contact with each other and pressed so that the coupling end faces are slightly deformed, and this deformation absorbs a polishing error or the like. Since the optical connector ferrule 3 is composed of a low hardness member having a hardness lower than that of the optical fiber 4, it is easy to absorb a polishing error or the like due to the deformation of the optical connector ferrule 3, and the optical coupling between the optical fibers 4 is surely performed. You can

Further, in the optical connector of the present invention, since the optical fiber may be projected by polishing the coupling end surface as described above, the projection of the end surface of the optical fiber 4 is also ensured, and from this point as well, the optical coupling is achieved. It can be said that the stability of can be achieved.

FIG. 3 shows a partial cross section of an optical connector according to another embodiment. This optical connector 1A is the same as the above-described embodiment except that the optical connector ferrule 3A is made of an epoxy resin containing calcium carbonate as a filler to improve dimensional stability. The same reference numerals are given to members having the same function as, and duplicate description will be omitted. The same applies to the point that the optical fiber 4 is fixed to the optical connector ferrule 3A, and then the end face of the optical fiber 4 and the end face of the optical connector ferrule 3A are polished as described above. In this embodiment, although the filler 10 made of calcium carbonate slightly protrudes (about 0.2 μm) from the end face of the optical connector ferrule 3 at the time of polishing, the end face of the optical fiber 4 is even thinner than that of the filler 10. The structure has a protrusion of 5 μm or more.

The optical connector 11 thus obtained is
As a result of individual evaluation, the average connection loss was 0.3 dB, and the reflection at the connection point was 40 dB.

Further, in order to prevent reflection at the connection point of the optical fiber when the optical connector is coupled, the surface of the protruding portion including the end face of the optical fiber is 5 ° with respect to the plane orthogonal to the optical axis of each optical fiber. As described above, it is preferable to incline by 8 °, for example.

FIG. 4 shows an example of an optical connector in which the coupling surface is inclined, (A) is a front view and (B) is a side view. In this optical connector 1B, the coupling end face 5 including the single face of the optical fiber 4 is 5 ° with respect to the plane orthogonal to the optical axis (the coupling end face 5
This is the same as the embodiment shown in FIG. 1 except that the polishing is performed so that the angle between the optical axis and the optical axis becomes 85 °. When 10 optical connectors 1B were evaluated, the average connection loss was 0.3 dB, and the reflection at the connection point was 50 dB or more, which was a very good result.

In the embodiment described above, an optical connector having two guide pin holes has been described, but of course the invention is not limited to this. Further, although the example in which the optical fibers are aligned in the direction connecting the guide pin holes is shown, it goes without saying that the optical fibers may be aligned in the direction orthogonal to this.

[0024]

As described above, since the optical connector of the present invention has the projecting portion on the coupling end surface and is more easily deformed than the conventional one when closely coupled, the optical fibers can be reliably optically coupled. Can be

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an optical connector according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a coupled state of the optical connector of the present invention.

FIG. 3 is a sectional view of an essential part of an optical connector according to another embodiment of the present invention.

FIG. 4 is a schematic view showing an optical connector according to still another embodiment of the present invention.

[Explanation of symbols]

 1,1A, 1B Optical connector 2 Guide pin hole 3 Optical connector ferrule 4 Optical fiber 5 Coupling end face

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Makoto Honjo Makoto Honjo 1 Taya-cho, Sakae-ku, Yokohama-shi, Kanagawa Sumitomo Electric Industries, Ltd. Yokohama Works (72) Toshiaki Kakii 1 Taya-cho, Sakae-ku, Yokohama, Kanagawa Sumitomo Electric Industrial Co., Ltd.Yokohama Works (72) Inventor Toru Yamanishi 1 Taya-cho, Sakae-ku, Yokohama-shi, Kanagawa Sumitomo Electric Industrial Co., Ltd. Yokohama Works (72) Inventor Shinji Nagasawa 1-1, Uchisaiwaicho, Chiyoda-ku, Tokyo No. 6 Nippon Telegraph and Telephone Corporation

Claims (3)

[Claims] 1. An optical connector in which an end face of an optical fiber is positioned and fixed to a coupling end face of an optical connector ferrule capable of fixing an optical fiber, and the coupling end faces are positioned and adhered to each other to optically couple the optical fibers to each other. An optical connector, wherein at least a coupling end surface of the connector ferrule is made of a low hardness member having a hardness lower than that of the optical fiber. 2. The optical connector according to claim 1, wherein the material of the optical connector ferrule is a plastic containing a filler having a hardness lower than that of the optical fiber. 3. The optical connector according to claim 1, wherein the coupling end surface is inclined by 5 ° or more with respect to a plane orthogonal to the optical axis of the optical fiber.