JP2557972Y2 - Connection structure of multi-core optical fiber connector - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a connection structure of a multi-core optical fiber connector in which there is no reverse of propagating light at the end of an optical fiber, and there is no misalignment between optical fibers, and thus good optical coupling is achieved. About.

[0002]

2. Description of the Related Art An optical fiber has a structure in which a propagating light is confined in a core by transmitting a propagating light through a cladding layer having a smaller refractive index than that of the core. As shown in FIG. 6, the connection between the optical fibers is performed by removing the coating of the optical fiber core 5 and burying the exposed optical fiber 4 in the multi-core optical fiber connector A. The end face of the optical fiber connector A is cut at a right angle and polished to expose the end of the optical fiber 4 and optically coupled to the end of the optical fiber of another multi-core optical fiber connector B. In the above, the alignment of the optical fibers 5 exposed on the end faces of the multi-core optical fiber connectors A and B is performed by providing fitting holes 1 on the end faces of the multi-core optical fiber connectors A and B, respectively. Positioning is performed through the guide pin 2, and the two multi-core optical fiber connectors A and B are pressed together. By the way, if the end of the optical fiber 4 is cut and polished at a right angle as described above, the propagating light in the optical fiber is reflected at the end of the optical fiber 4, and the reflected light goes backward in the optical fiber. Therefore, there is a problem that the light source is adversely affected and the light propagation characteristics are impaired. For this reason, as shown in FIG. 7, the end face of the multi-core optical fiber connector A is polished obliquely at an angle of θ with respect to the perpendicular, and the reflected light at the end of the optical fiber 4 is reflected by the optical fiber 4. A way to deviate from the axis has been proposed.

[0003]

However, when the end faces of the multi-core optical fiber connector whose end faces are polished obliquely are joined and pressed, the joining faces (mating faces) move relative to each other, and the gap between the optical axes of the optical fibers. There has been a problem that the displacement occurs and the optical coupling property decreases. That is, FIGS. 8A and 8B are side views before and after pressing of the multi-core optical fiber connector with the joining surface inclined vertically, and FIGS. 8C and 8D are front views of the connecting structure of the connector before and after pressing. As shown, before the pressing, the axes of the fitting holes 1 of the two multi-core optical fiber connectors A and B and the axis of the optical fiber end 5 are aligned (FIGS. 1A and 1C).
After pressing, the multi-fiber optical fiber connectors A and B relatively move along the joint surface, causing a deviation between the optical axes of the optical fibers 4 and 14 (FIGS. 2 and 3).

[0004]

The present invention has made intensive studies in view of such a situation, and the shift between the optical fibers of the multi-core optical fiber connector described above is shown in FIG. As shown in the enlarged side view after pressing B,
Since the multi-core optical fiber connectors A and B move relatively in the acute angle direction of the end face by the distance [δ + ε] of the clearance δ between the fitting hole 1 and the guide pin 2 and the amount of elastic deformation ε of the guide pin 2. This led to further research and completed the present invention. That is, the present invention embeds a plurality of optical fibers, and connects the end faces of the two multi-core optical fiber connectors whose ends are exposed to guide pins in a plurality of fitting holes provided in each end face. In the connection structure of the multi-core optical fiber connector, which is positioned by fitting, and the optical fiber ends are optically coupled to each other, an end face of the multi-core optical fiber connector is polished with an inclination, A pair of fitting holes for fitting the guide pins of the two optical fiber connectors is relatively [δ + ε + 1].
μm to [δ + ε-1] μm (where δ is the clearance between the fitting hole and the guide pin, ε is the amount of elastic deformation in the direction of inclination of the guide pin due to the pressing force, and the unit is μm) It is characterized in that it is provided displaced by a predetermined distance in the acute angle direction of the inclined surface.

In the connection structure of the multi-core optical fiber connector according to the present invention, two mating holes, which are provided on the inclined end face of the multi-core optical fiber connector, for fitting the same guide pin, are formed on the inclined end face. In the direction of the acute angle side, that is, in the direction in which the optical fibers move by pressing, the optical fibers that are to be optically coupled to each other when the end faces of the multi-core optical fiber connector are pressed against each other when the end faces of the multi-core optical fiber connectors are pressed are each accurate. The optical coupling is good.

The relationship between the pressing load when the optical fiber connector is pressed and the displacement (relative movement distance) of the inclined end face of the connector will be described below with reference to FIG. As the multi-core optical fiber connector, a multi-core optical fiber connector in which the end face shown in FIG.
The material of the connector 1 is FRP in which 70% of glass filler is mixed with epoxy resin, and the inner diameter of the fitting hole 2 is 697.3 μm.
φ, and a 697.0 μmφ stainless steel guide pin was used as the guide pin 3. As can be seen from FIG. 1, the amount of displacement between the ends of the optical fibers to be optically coupled increases in proportion to the pressing load. When the load is 1kgf, the total displacement is
0.6 μmφ, of which 0.3 μm is due to the clearance δ between the guide pin and the fitting hole, and the remaining 0.3 μm is due to the elastic deformation ε of the fitting guide pin.

The clearance between the fitting hole and the guide pin is generally expected to be about 1 μm in consideration of workability and dimensional tolerance of parts. Also, in order to ensure connection reliability, generally 1-2 kg
A pressing load of / cm ² is applied, so that the guide pin is elastically deformed. Since the clearance and the pressing force are slightly different depending on the type of the multi-core optical fiber connector, the displacement between the fitting holes is determined by actually measuring in advance for each multi-core optical fiber connector to be used. In the present invention, the relative displacement distance between the fitting holes is [δ + ε + 1] μm to [δ + ε−1] μm.
The reason for limiting the distance to a predetermined distance within the range represented by the equation of m (where δ is the clearance between the fitting hole and the guide pin, ε is the amount of elastic deformation of the guide pin in the inclination direction due to the pressing force, unit μm) , [Δ + ε + 1] μm, or
-1] Even if it is less than [mu] m, the optical coupling at the connector part sharply decreases.

In the present invention, the structure of a mold for molding a multi-core optical fiber connector will be described with reference to the drawings. FIG.
FIG. 3 is an exploded view of the mold. The mold has a V-groove block 8 for positioning and holding a core pin 6 for forming a fitting hole and a core pin 7 for inserting an optical fiber, and the multi-core optical fiber connector engages an upper mold 9 and a lower mold 10. Then, epoxy resin is injected into the internal space, and transfer molding is performed. In the above, by inclining the molded product (connector) side of the V-groove block at a predetermined angle with respect to the V-groove axis, the joining end surface of the connector can be formed obliquely, and no undercut is required. The multi-core optical fiber connector molded in this manner can be easily polished by using a polishing machine having the butted end face shown in FIG. 5 and the sample holder 12 set at an angle to the grindstone 13. it can.

[0009]

In the connection structure of the multi-core optical fiber connector of the present invention, a plurality of optical fibers are buried, and the end surfaces of two multi-core optical fiber connectors whose ends are exposed are provided on the respective end surfaces. In the connection structure of the multi-core optical fiber connector in which the guide pins are positioned by fitting the plurality of fitting holes, and the optical fiber ends are optically coupled to each other, the end face of the multi-core optical fiber connector is The pair of fitting holes, which are polished and tilted and are fitted with the guide pins of the two optical fiber connectors, are relatively [δ + ε + 1].
μm to [δ + ε-1] μm (where δ is the clearance between the fitting hole and the guide pin, ε is the amount of elastic deformation in the direction of inclination of the guide pin due to the pressing force, and the unit is μm) Since it is provided to be displaced in the acute angle direction of the inclined surface by a predetermined distance, when the end face of the multi-core optical fiber connector is pressed and optically coupled, the fitting hole is displaced by the distance and the optical fibers are connected to each other. Good optical bonding is achieved.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments. Embodiment 1 FIGS. 2A and 2B are side views before and after pressing showing an embodiment of a multi-core optical fiber connector in which the connection surface is inclined in the up-down direction according to the present invention. FIGS. It is a front view of the connection structure before and after pressing. Multi-core optical fiber connectors A and B
Are provided so as to be relatively displaced from each other by a predetermined distance in an acute angle direction which is displaced when pressed.
C) When the guide pins 2 are fitted into the two fitting holes 1 and both of them are clipped and pressed with a predetermined pressure, the bonding surface relatively moves by a predetermined distance in the acute angle direction, and the optical fibers 4 (Fig. B, d). In Example 1, the amount of light insertion loss (the amount of loss in the connector) was examined by changing the relative displacement distance of the fitting hole in various ways. Table 1 shows the results
It was shown to. In addition, by preliminary experiments, [δ
+ Ε] was found to be 1.4 μm. An optical fiber having a core diameter of 10 μm was used.

[0011]

[Table 1]

As is clear from Table 1, the products of the present invention (No.
In Nos. 1 to 3, the amount of light insertion loss was small and good optical coupling was achieved. In contrast, No. 4 of the comparative example exceeded the displacement distance range of the present invention, and No. 5 was not displaced, so that the light insertion loss increased in each case.

Embodiment 2 FIGS. 3A and 3B are plan views of a multi-core optical fiber connector according to the present invention before and after pressing, showing an embodiment of a multi-core optical fiber connector in which the joining surface is inclined in the left-right direction. It is a front view before and after pressing of the connection structure of the connector. Multi-core optical fiber connectors A and B
Are provided so as to be relatively displaced from each other by a predetermined distance in an acute angle direction which is displaced when pressed.
C) When the guide pins 2 are fitted into the two fitting holes 1 and both are pressed with the clip 3 at a predetermined pressure, the bonding surface relatively moves by a predetermined distance in the acute angle direction of the bonding surface, Optical coupling between the optical fibers 5 is performed ((b) and (d) in the figure). In the case of the second embodiment, as in the first embodiment, the relative insertion distance of the fitting hole was varied and the amount of light insertion loss was investigated. In each of the optical sensors which were displaced by a predetermined distance, the same good optical coupling as in Example 1 was achieved.

[0014]

As described above, the connection structure of the multi-fiber optical fiber connector according to the present invention has good optical coupling because neither backward propagation of the propagating light at the end of the optical fiber nor deviation of the optical axis occurs. Has a remarkable industrial effect.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a relationship between a pressing load and a displacement amount between optical fiber ends.

FIG. 2 is a side view and a front view showing an embodiment of the connection structure of the multi-core optical fiber connector of the present invention.

FIG. 3 is a plan view and a front view showing another embodiment of the connection structure of the multi-core optical fiber connector of the present invention.

FIG. 4 is an explanatory view of a mold for molding the multi-core optical fiber connector of the present invention.

FIG. 5 is an explanatory view of a method of obliquely polishing the end face of the multi-core optical fiber connector according to the present invention.

FIG. 6 is a perspective view of a multi-core optical fiber connector.

FIG. 7 is a perspective view of a multi-core optical fiber connector in which an end face is obliquely polished in a vertical direction.

FIG. 8 is a side view and a front view showing a connection structure of a conventional multi-core optical fiber connector.

FIG. 9 is an enlarged side view of the multi-fiber optical fiber connectors A and B after being pressed.

[Explanation of symbols]

 A, B Multi-core optical fiber connector 1, 11 Fitting hole 2 Guide pin 3 Clip 4, 14 Optical fiber 5, 15 Multi-core optical fiber core wire 6 Core pin for forming fitting hole 7 Core pin for forming optical fiber insertion hole 8 V Groove block 9 Upper die 10 Lower die 12 Sample holder 13 Whetstone

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Yoshiyuki Okawa 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. (72) Hiroyuki Yamada 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Furukawa Inside Electric Industry Co., Ltd. (72) Inventor Toshiaki Satake 1-1-6 Uchisaiwai-cho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (56) References JP-A-5-34550 (JP, A) 57804 (JP, U)

Claims (1)

(57) [Scope of request for utility model registration] 1. A multi-fiber optical fiber connector having a plurality of optical fibers buried therein and exposing ends thereof, and guide pins are fitted into a plurality of fitting holes provided in the respective end faces. In the connection structure of a multi-core optical fiber connector in which the ends of the optical fibers are optically coupled with each other by positioning, the end surface of the multi-core optical fiber connector is polished with an inclination, and The pair of fitting holes for fitting the guide pins of the optical fiber connector are relatively represented by a formula [δ + ε + 1] μm to [δ + ε−1] μm (where δ is the fitting hole and the guide pin). Is the amount of elastic deformation of the guide pin in the direction of inclination due to the pressing force, which is displaced in the acute angle direction of the inclined surface by a predetermined distance within a range shown in (μm). Connection of multi-core optical fiber connector Construction.