JP3809905B2 - Optical fiber connection method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
According to the present invention, an optical fiber is inserted from the outside into the optical fiber hole of a so-called optical connector that has an optical fiber built in the optical fiber hole in advance, and the built-in optical fiber and the insertion side optical fiber are inserted into the optical fiber hole. The present invention relates to an optical fiber connection method for butt connection.
[0002]
[Prior art]
Conventionally, various on-site optical connectors for assembling optical connectors at connection sites other than factories have been proposed. On-site optical connectors are built-in short optical fibers halfway along the optical connector, and the connection end faces are usually polished in advance. In some cases, polishing may be omitted by molding on a smooth surface. In the latter case, the end face of the optical fiber remains a smooth cut surface, and connection using a matching agent is performed. In the field, the optical connector is assembled by abutting and fixing the built-in optical fiber and the insertion-side optical fiber inserted from the outside of the optical connector within the optical fiber hole of the optical connector.
[0003]
In this type of on-site optical connector, a pair of upper and lower elements that form an optical fiber hole are clamped by, for example, a U-shaped spring at the rear end of a ferrule that has been fixed with an optical fiber and end-face polished. There is a mechanism in which a so-called mechanical splice is integrally provided (see Japanese Patent Laid-Open No. 10-206688).
When assembling an on-site optical connector with a built-in connection mechanism, the pair of upper and lower elements of the connection mechanism are pushed open by an opening member, and the optical fiber hole formed by the upper and lower elements is slightly widened. The insertion-side optical fiber is inserted and butted against the built-in optical fiber, and then the open member is removed and the upper and lower elements are clamped by springs, thereby fixing the built-in optical fiber and the insertion-side optical fiber in the butted connection state.
[0004]
Conventionally, when assembling the above optical connector, the operation of inserting the insertion-side optical fiber into the optical fiber hole of the connection mechanism has been usually performed manually. Therefore, the abutting pressure when the end surface of the insertion-side optical fiber is abutted against the end surface of the built-in optical fiber is dependent only on the sense of the hand.
A simple optical connector assembly tool may be used. In this case, after inserting the insertion side optical fiber into the optical fiber hole of the optical connector using the assembly tool, the insertion side optical fiber is urged by the biasing force of the spring. Against the built-in optical fiber.
[0005]
[Problems to be solved by the invention]
In the method of manually inserting the optical fiber as described above, since the optical fiber hole is small and difficult to insert, the work efficiency is extremely poor.
In order to connect an optical fiber with low connection loss, it is necessary that the end face of the insertion side optical fiber and the end face of the built-in optical fiber are abutted with an appropriate pressure. If the abutting pressure of the optical fiber depends only on the sense of the hand, it is difficult to obtain a desired and always constant abutting pressure.
In the case of assembling using an assembly tool, the abutting pressure is obtained by the force of the spring. However, the spring elasticity is easily changed over time, the optical fiber is extremely thin, and the appropriate abutting pressure is, for example, several tens of grams. It was difficult to keep a proper abutting pressure because it was a small one, and the abutting pressure was too strong.
[0006]
The present invention has been made in view of the above circumstances, and facilitates the operation of inserting an optical fiber into an optical fiber hole of an optical connector, and when making a butt connection between optical fibers in the optical fiber hole of an optical connector, It is an object of the present invention to provide an optical fiber connection method that enables optical fibers to be matched with each other at a desired and always constant pressure.
[0008]
According to the first aspect of the present invention, an optical fiber is inserted from the outside into the optical fiber hole of the optical connector in which the optical fiber is previously incorporated in the optical fiber hole, and the built-in optical fiber and the insertion side optical fiber are inserted into the optical fiber hole. An optical fiber connection method for butt connection,
The insertion side optical fiber is fixed on the optical fiber holding jig with the tip thereof facing the optical fiber hole of the optical connector, and the fixing position of the insertion side optical fiber and the vicinity of the tip of the insertion side optical fiber are slidably accommodated. In addition, the intermediate portion of the guide portion that projects with the tip aligned in parallel is held in a bent state, and the optical fiber holding jig advances toward the optical connector in the bent state. The insertion side optical fiber is inserted into the optical fiber hole by advancing to a stopper position that defines a limit, then the bending of the insertion side optical fiber is released, and the insertion side optical fiber is butt-connected to the built-in optical fiber. To do.
[0009]
According to a second aspect of the present invention, there is provided a ferrule in which an optical fiber is inserted and fixed in a ferrule optical fiber hole, and a part thereof extends from the rear end of the ferrule, and is provided on the rear end side of the ferrule. An optical fiber that butt-connects the built-in optical fiber and the insertion-side optical fiber when assembling an optical connector having a connection mechanism that butt-connects the extended built-in optical fiber and the insertion-side optical fiber inserted from the outside A connection method,
The insertion-side optical fiber is fixed on an optical fiber holding jig, and the fixing position of the insertion-side optical fiber and the vicinity of the distal end of the insertion-side optical fiber are slidably received and the distal ends thereof are aligned in parallel and protruded. Hold the middle part with the guide part in a bent state, and move the optical fiber holding jig toward the optical connector connecting mechanism in the bent state to the stopper position that defines the advance limit of the optical fiber holding jig. The insertion-side optical fiber is inserted into the optical fiber hole of the connection mechanism, the bending of the insertion-side optical fiber is then released, and the insertion-side optical fiber is butt-connected to the built-in optical fiber in the connection mechanism. .
[0010]
According to a third aspect of the present invention, there is provided a pair of upper and lower elements that are provided with alignment grooves on at least one to form an optical fiber hole, a spring that elastically clamps both elements, and an elastic gripping force of the spring. Light for connecting the built-in optical fiber previously accommodated in the optical fiber hole of the connection mechanism and the insertion-side optical fiber inserted from the outside in a connection mechanism provided with an opening means that pushes between the pair of elements. A fiber connection method,
The insertion-side optical fiber is fixed on an optical fiber holding jig, and the fixing position of the insertion-side optical fiber and the vicinity of the distal end of the insertion-side optical fiber are slidably received and the distal ends thereof are aligned in parallel and protruded. Hold the intermediate part with the guide part in a bent state, and insert the optical fiber holding jig in the bent state toward the connection mechanism and to the stopper position that defines the advance limit of the optical fiber holding jig. The side optical fiber is inserted into the optical fiber hole of the connection mechanism, and then the bending of the insertion side optical fiber is released, and the insertion side optical fiber is butt-connected to the built-in optical fiber in the connection mechanism.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an optical connector 10 and an optical fiber (hereinafter referred to as an insertion-side optical fiber) 11 to be inserted into the optical connector 10 and connected to the optical connector assembly tool 1 used in the optical fiber connection method of one embodiment of the present invention. FIG. 2 is a front view of FIG. 1. A bare fiber from which the coating of the insertion-side optical fiber 11 has been removed is denoted by 11a, and a coating portion is denoted by 11b. In the following description, the portion of the bare fiber 11a or the portion of the covering portion 11b is also simply referred to as the insertion side optical fiber 11 in some cases.
[0012]
This optical connector assembling tool 1 includes a tool main body 2 for holding an optical connector 10, a slide base 3 integral with the tool main body 2, and a guide 3a of the sudido base 3 in the optical fiber connecting direction (FIG. 1, FIG. 2 in the left-right direction) and an optical fiber holding jig 4 slidably provided in the front-rear direction. The optical fiber holding jig 4 includes a fixing portion 7 that fixes the insertion side optical fiber 11 toward the optical fiber hole 10a of the optical connector 10 on the tool body 2, and the vicinity of the tip of the covering portion 11b of the insertion side optical fiber 11. And a spacer for holding the intermediate portion between the position of the fixing portion 7 and the position of the guide portion 8 of the insertion-side optical fiber 11 in a bent state. (Flexure holding means) 9 is provided. Further, a stopper 5 is provided on the slide table 3 to define the forward limit position of the optical fiber holding jig 4.
[0013]
The optical connector 10 will be described in detail with reference to FIGS. 3 to 5. The optical connector 10 is a two-core connector, and is integrated with an optical ferrule 12 having a substantially square shape and a rear end side of the optical ferrule 12. And a connection mechanism 13 provided.
In the ferrule 12, the optical fiber 18 is inserted and fixed in each of the two optical fiber holes 12a, and a part of the ferrule 12 extends from the rear end of the ferrule, and the end face 12b is obliquely polished. This ferrule 12 is generally similar in configuration to a ferrule for a fitting pin alignment type optical connector (JIS C 5981 F12 type multi-fiber optical fiber connector) generally called an MT connector. The ferrule 12 can be formed of a hard resin such as an epoxy resin. The optical ferrule 12 and the connection mechanism 13 integrated therewith are accommodated in a housing 21 (see FIGS. 1 and 2).
The connection mechanism 13 has a structure in which a pair of upper and lower elements, that is, a main body 14 and a lid 15 are clamped by a U-shaped leaf spring 16. The main body 14 includes a base portion 14a and a ferrule fitting portion 14b at the front end portion (left side in FIG. 4). The rear end portion of the ferrule 12 (in the fitting hollow portion 14c provided in the ferrule fitting portion 14b) The right side of FIG. 4 is fitted and fixed with an adhesive, and the ferrule 12 and the main body 14 are integrated.
In addition, an aligning groove 14d made of, for example, a V groove is formed on the front side of the upper surface of the main body 14, and the optical fiber hole 10a is formed by the aligning groove 14d and the flat surface or groove on the lid 15 side. ing. In addition, optical fiber covering portion receiving grooves 14e and 15e are formed on the rear side of the main body 14 and the lid body 15 so that an optical fiber covering portion receiving hole 19 having the same axis as the optical fiber hole 10a is formed. In addition, a tapered optical fiber inlet 19a for facilitating insertion of the optical fiber is formed at the rear end portion of the optical fiber covering portion receiving hole 19.
In addition, an insertion port 17 into which a wedge-shaped opening member 20 for pushing open between the main body 14 and the lid 15 against the elastic gripping force of the spring 16 is formed on the side surface of the connection mechanism 13. . The insertion port 17 is formed by recesses 14 f and 15 f provided at the edges of both the main body 14 and the lid 15. In addition, although the material of the main body 14 and the cover body 15 is not specifically limited, It can form with hard resin or a metal.
The main body 14 of the connection mechanism 13 may be formed integrally with the ferrule 12 and resin.
[0014]
When the optical connector 10 is assembled using the optical connector assembling tool 1 described above, the optical connector 10 is fixed on the tool main body 2, the opening member 20 is inserted into the insertion port 17, and the main body 14 and the lid of the connection mechanism 13 are covered. Push between the body 15 and open. As a result, the optical fiber hole 10a formed between the main body 14 of the connection mechanism 13 and the lid body 15 is slightly expanded. Note that a portion of the built-in optical fiber 18 of the optical connector 10 that extends from the rear end of the ferrule is inserted up to an intermediate position in the optical fiber hole 10 a of the connection mechanism 13.
Next, the insertion side optical fiber 11 is inserted into the guide portion 8 through the fixing portion 7 of the optical fiber holding jig 4 at a position where the optical fiber holding jig 4 is retracted (for example, a position where the optical fiber holding jig 4 is applied to the rear side stopper 6). The insertion side optical fiber 11 is fixed by the fixing portion 7. At this time, the protruding length L (see the two-dot chain line in FIG. 6) from the position of the fixing portion 7 of the insertion side optical fiber 11 to the tip is set to a predetermined length obtained in advance.
Next, the spacers 9 are interposed between the left and right insertion-side optical fibers 11 so that the left and right insertion-side optical fibers 11 are bent and held with their tips aligned (state of FIG. 1). In this case, the two insertion-side optical fibers 11 are bent by the fixing portion 7 and the guide portion 8 so that the middle swells outward.
Next, when the optical fiber holding jig 4 is slid in the direction of arrow A on the slide portion 3 and moved forward until it hits the stopper 5, the insertion-side optical fiber 11 tapers into the optical fiber hole 10 a of the connection mechanism 13 of the optical connector 10. It is inserted from the shaped inlet 19a. FIG. 7 illustrates this stage. As described above, the insertion-side optical fiber 11 can be correctly inserted into the optical fiber hole 10a simply by sliding the optical fiber holding jig 4, so that the optical fiber can be easily inserted and the working efficiency is remarkably improved.
[0015]
Next, when the spacer 9 is removed and the bending of the insertion side optical fiber 11 is released, the optical fiber 11 moves forward in the optical fiber hole 10a due to the force of the bending of the insertion side optical fiber 11 to return, that is, due to its own rigidity. The insertion-side optical fiber 11 and the built-in optical fiber 18 are straight in the optical fiber hole 10a, and the end face of the insertion-side optical fiber 11 and the end face of the built-in optical fiber 18 are moderate. Butt connection is made with the butting pressure. Next, when the opening member 20 is extracted from the insertion port 17, the optical fiber 11 is clamped and held in the connection mechanism 13 by the clamping force of the spring 16, and the connected state is maintained.
[0016]
At the time of the butt connection between the optical fibers 18 and 11 described above, the force (the fiber bending restoring force due to its own rigidity) that the bending of the optical fiber tries to return between the end surface of the insertion-side optical fiber 11 and the end surface of the built-in optical fiber 18. In order to make a butt connection with an appropriate abutting pressure, the insertion side optical fiber 11 after abutting against the built-in optical fiber 18 needs to leave an appropriate amount of deflection. For this purpose, as shown in FIG. 6, the fiber straight length L (the length of the portion indicated by the two-dot chain line) of the bent portion from the position of the fixing portion 7 to the tip of the insertion-side optical fiber 11 is determined at the time of butt connection. It is necessary to set an appropriate distance ΔL longer than the distance L ′ from the fixed portion 7 position to the connection end face position P. The relationship between ΔL and the magnitude of the abutment pressure corresponding to ΔL is obtained in advance by experiments or the like, and by setting this ΔL to the obtained value, the end face of the insertion-side optical fiber 11 is placed on the optical fiber 18. on the end face as possible out to connect butt at the desired abutment pressure.
[0017]
According to the above-described optical fiber connection method, the abutting pressure is obtained by the flexibility of the optical fiber, so that the abutting pressure can be easily made constant as compared with the conventional work that relies on the sense of the human hand. This enables stable assembly with little variation, and is extremely reproducible. In addition, compared to a conventional method in which optical fibers are butt-connected by the force of a spring, there is less fear that the abutting pressure between the optical fibers will be stronger than necessary, and the connection characteristics can be prevented from being impaired.
The above embodiment is a case of a two-fiber optical connector, which is suitable for application to a two-fiber optical connector, but can also be applied to a single-fiber optical connector. It can also be applied to a multi-fiber optical connector having three or more cores. When applied to a multi-fiber optical connector having three or more cores, all the insertion side optical fibers may be bent in the same direction.
The two optical fibers butt-connected in the connection mechanism 13 are usually the same type of optical fiber, but different types of optical fibers, for example, a single mode optical fiber and a multimode optical fiber may be connected.
[0018]
The above-described embodiment is directed to the optical connector 10 having a structure in which the ferrule 2 and the connection mechanism 13 that clamps the pair of upper and lower elements forming the optical fiber hole with, for example, a U-shaped spring are integrated. The present invention is also applicable to butt connection of optical fibers in an independent connection mechanism, that is, a connection mechanism 13 similar to the connection mechanism 13 in the optical connector 10 in FIGS. 3 to 5 and independent from the ferrule 12 (so-called mechanical splice itself). Applicable. That is, when connecting the two optical fibers in the separate attachments, it can be employed the onset bright light off Aiba connection.
In this case, the tip of one of the fixed optical fibers is accommodated in the optical fiber hole of the mechanical splice (connection mechanism), and the other optical fiber is held in a bent state on the optical fiber holding jig to move forward. To be inserted into the optical fiber hole of the mechanical splice, and then the bending is released.
[0019]
The present invention is also applicable to an optical connector 28 that does not use a mechanical splice as shown in FIG. In this optical connector 28, the rear end of the built-in optical fiber 32 is in the optical fiber hole 29 a of the ferrule 29, and the built-in optical fiber 32 and the optical fiber (insertion side optical fiber) 11 inserted from the outside are connected to the ferrule 29. In this configuration, the optical fiber holes 29a are butt-connected. The ferrule 29 is substantially the same as a ferrule for a fitting pin alignment type optical connector called an MT connector (F12 type multi-fiber optical fiber connector of JIS C 5981), and has a polished tip surface 29b. Reference numeral 31 denotes a rubber boot for protecting an optical fiber.
[0020]
Even when the insertion-side optical fiber 11 is abutted and connected to the built-in optical fiber 32 of the optical connector 28, it can be connected by an optical connector assembling tool similar to that shown in FIGS. That is, the insertion side optical fiber 11 is held in a bent state on the optical fiber holding jig, and is then slid to place the insertion side optical fiber 11 (the bare fiber 11a) in the light of the ferrule 29 as shown in FIG. The optical fiber 11 is inserted into the fiber hole 29a, and then the bending of the insertion side optical fiber 11 is released. Thereby, the butt connection of moderate butting pressure can be performed like the above-mentioned. Thereafter, for example, an epoxy adhesive 32 is injected into the opening 30 to fix the insertion-side optical fiber 11.
[0021]
Although the present invention has been described only for the case where an optical fiber is inserted and connected from the outside to an article such as a ferrule that already contains an optical fiber, the present invention utilizes the rigidity of the optical fiber itself. Therefore, it is important to apply a forward force without applying excessive force to the optical fiber, and to ensure a stable abutment force at the same time as the forward movement or after the forward movement as necessary (however, it is important to Is a generic term including the case where the tip of the optical fiber moves and the case where the tip of the optical fiber does not move but the portion other than the tip is displaced by the straightening of the optical fiber). Therefore, the device, mechanism, instrument, or the other object on which the optical fiber is inserted or the optical fiber is going to advance by the bending force is not limited to the ferrule built-in fiber. First, a method of giving a desired amount of bending to the optical fiber in advance and releasing the bending to advance the optical fiber mainly by its own force so that the tip of the optical fiber reaches a desired position. The present invention can be applied to various types of objects. For example, it is used as an optical connector to connect to a counterpart optical connector, not to an optical connector type, but to a counterpart optical fiber, to an optical element, and there is no counterpart optical fiber, but the light to the optical positioning member It can be suitably used for inserting and fixing fibers (for example, inserting and fixing optical fibers into an optical fiber array or an optical ferrule).
[0022]
【The invention's effect】
According to the present invention, the optical connector is held on the tool body, the insertion-side optical fiber is bent on the optical fiber holding jig , and the tip thereof is parallel and slidably protrudes. The optical fiber holding jig is slid on the slide portion and moved forward until it hits the stopper, and the insertion side optical fiber is inserted into the optical fiber hole of the optical connector, and then the bending is released. Since the fiber is butt-connected to the built-in optical fiber, the following effects can be obtained.
Since the insertion side optical fiber can be inserted into the optical fiber hole of the optical connector by simply sliding the optical fiber holding jig on the slide portion, the optical fiber can be inserted very easily, and the work efficiency is remarkably improved.
Further, since the bending force of the optical fiber on the insertion side tries to return to obtain the abutting pressure between the optical fibers, the force on which the bending is returned can be converted into a fiber fixing portion, a guide portion, a bending holding means, a stopper, etc. With this configuration, it is possible to set the appropriate size with extremely high reproducibility, so it is possible to easily make the abutment pressure constant compared to the work that relies on the sense of human hands, Stable assembly with little variation is possible, and reproducibility is extremely high. In addition, compared to a conventional method in which optical fibers are butt-connected by the force of a spring, the abutting pressure between optical fibers is less likely to increase or fluctuate more than necessary, and the connection characteristics can be prevented from being impaired.
[Brief description of the drawings]
FIG. 1, showing an embodiment of the present invention, is a plan view of an optical connector assembly tool in a state where an optical connector and an insertion side optical fiber are held.
FIG. 2 is a front view of FIG. 1;
3 is a perspective view showing details of the optical connector in FIG. 1. FIG.
4 is a cross-sectional view taken along the line BB in FIG.
5 is a perspective view showing a main body of the connection mechanism in FIG. 3. FIG.
FIG. 6 is a diagram for explaining a method of abutting the end face of the optical fiber against the end face of the stored optical fiber with a desired force when the optical fibers are butt-connected in the optical connector.
FIG. 7 is a cross-sectional view showing details of a procedure for connecting an optical fiber in the optical connector.
FIG. 8 is a cross-sectional view of an optical connector not using a mechanical splice, showing another example of an optical connector targeted by the optical fiber connection method of the present invention.
9 is a cross-sectional view showing a state after the optical connector shown in FIG. 8 is assembled.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Optical connector assembly tool 2 Tool main body 3 Slide stand 4 Optical fiber holding jig 5 Stopper 6 Back side stopper 7 Fixing part 8 Guide part 9 Spacer (flexure holding mechanism)
DESCRIPTION OF SYMBOLS 10, 28 Optical connector 10a Optical fiber hole 11 (of optical connector) Insertion side optical fiber 12 Ferrule 12a (of ferrule) Optical fiber hole 13 Connection mechanism 14 Main body 14a Base part 14b Ferrule fitting part 14c Fitting hollow part 14d Alignment Grooves 14e and 15e Optical fiber covering portion receiving grooves 14f and 15f Recess 15 Lid 16 Plate spring 17 Insertion ports 18 and 32 Built-in optical fiber 19 Optical fiber covering portion receiving hole
20 Opening member

Claims (3)

An optical fiber connection method in which an optical fiber is inserted from the outside into the optical fiber hole of an optical connector in which the optical fiber is previously incorporated in the optical fiber hole, and the built-in optical fiber and the insertion-side optical fiber are butt-connected in the optical fiber hole Because
The insertion side optical fiber is fixed on the optical fiber holding jig with the tip thereof facing the optical fiber hole of the optical connector, and the fixing position of the insertion side optical fiber and the vicinity of the tip of the insertion side optical fiber are slidably accommodated. In addition, the intermediate portion of the guide portion that projects with the tip aligned in parallel is held in a bent state, and the optical fiber holding jig advances toward the optical connector in the bent state. The insertion side optical fiber is inserted into the optical fiber hole by advancing to a stopper position that defines a limit, then the bending of the insertion side optical fiber is released, and the insertion side optical fiber is butt-connected to the built-in optical fiber. Optical fiber connection method. A ferrule in which an optical fiber is inserted and fixed in the ferrule optical fiber hole and incorporated therein, and a part thereof extends from the rear end of the ferrule, and a built-in optical fiber provided on the rear end side of the ferrule and extending from the ferrule; When assembling an optical connector having a connection mechanism that butt-connects an insertion-side optical fiber inserted from the outside, an optical fiber connection method that butt-connects the built-in optical fiber and the insertion-side optical fiber,
The insertion-side optical fiber is fixed on an optical fiber holding jig, and the fixing position of the insertion-side optical fiber and the vicinity of the distal end of the insertion-side optical fiber are slidably received and the distal ends thereof are aligned in parallel and protruded. Hold the middle part with the guide part in a bent state, and move the optical fiber holding jig toward the optical connector connecting mechanism in the bent state to the stopper position that defines the advance limit of the optical fiber holding jig. The insertion-side optical fiber is inserted into the optical fiber hole of the connection mechanism, the bending of the insertion-side optical fiber is then released, and the insertion-side optical fiber is butt-connected to the built-in optical fiber in the connection mechanism. Optical fiber connection method. A pair of upper and lower elements that form an optical fiber hole with an alignment groove in at least one of them, a spring that elastically clamps both elements, and an elastic gripping force of the spring between the pair of elements An optical fiber connection method in which a built-in optical fiber previously accommodated in an optical fiber hole of the connection mechanism and an insertion-side optical fiber inserted from the outside are butt-connected in a connection mechanism having an opening means for pushing and opening,
The insertion-side optical fiber is fixed on an optical fiber holding jig, and the fixing position of the insertion-side optical fiber and the vicinity of the distal end of the insertion-side optical fiber are slidably received and the distal ends thereof are aligned in parallel and protruded. Hold the intermediate part with the guide part in a bent state, and insert the optical fiber holding jig in the bent state toward the connection mechanism and to the stopper position that defines the advance limit of the optical fiber holding jig. An optical fiber connection characterized by inserting the side optical fiber into the optical fiber hole of the connection mechanism, then releasing the bending of the insertion side optical fiber and connecting the insertion side optical fiber to the built-in optical fiber in the connection mechanism Method.

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