JPH08248265A - Production of optical connector - Google Patents

Abstract

PURPOSE: To provide a method capable of easily making the front end of a ferrule for an optical fiber which does not require polishing at the front end face of the ferrule of an optical connector mounted with the optical fiber at the ferrule and the front end face of the optical fiber flush with each other or unifying the length from the front end face of the ferrule to the front end face of the optical fiber with good accuracy, thereby producing this kind of the optical connector at a low cost. CONSTITUTION: The front end face of the optical fiber 4 is projected from the front end face of the ferrule 1. The front end face of the optical fiber 4 is cleaned in this sate by a cleaning jig 30, such as air cleaner and thereafter the front end face of the optical fiber 4 is pressed toward the front end face of the ferrule 1 by a member 22 having a reference plane to make the front end face of the optical fiber 4 and the front end face of the ferrule 1 flush with each other. An adhesive 10 is injected in this state from an adhesive injection port 6 of the ferrule 1 to adhere and fix the optical fiber 4 and the ferrule 1, by which the optical connector without requiring the polishing of the front end face of the ferrule 1 is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical connector.

[0002]

2. Description of the Related Art Conventionally, optical connectors have been widely used as means for detachably connecting optical fibers. One of the components of this optical connector is a ferrule that holds an optical fiber end. An example of a typical ferrule is shown in FIGS. As shown in these figures, a pair of guide pin holes 2 on both sides and a plurality of optical fiber insertion holes 3 inside the ferrule 1 are provided on the connection end surface (hereinafter simply referred to as the front end surface) of the ferrule 1. . Corresponding to this optical fiber insertion hole 3, a V groove 5 for guiding the bare optical fiber 4 whose coating has been removed to the optical fiber insertion hole 3 is provided inside the ferrule 1, and this V groove 5 is provided. An adhesive injection port 6 is provided so as to face it.

A tape-shaped optical fiber core wire 8 formed by removing the coating on the front end portion of the ferrule 1 thus formed to expose the optical fiber 4 is inserted, and the optical fiber 4 is used as a guide V. After being inserted into the optical fiber insertion hole 3 which is guided by the groove 5 and pre-filled with the adhesive 10, the tip is positioned by the method described later, and then the adhesive injection port 6
Then, the adhesive 10 is additionally filled, both are integrated with the adhesive 10, and finally the front end surface of the ferrule 1 is polished to form an optical connector. Reference numeral 2a is a guide pin for axis alignment when connecting the obtained optical connectors. The tape-shaped optical fiber core wire 8 is formed by arranging a plurality of optical fiber wires, each of which has a primary coating on the optical fiber 4, arranged in parallel in a plane and collectively covering the optical fiber wires. Reference numeral 9 in the figure denotes a protective boot that covers the optical fiber core wire 8 when the tape-shaped optical fiber core wire 8 is inserted into the ferrule 1. Normally, the tape-shaped optical fiber core wire 8 is attached to the ferrule 1. Before insertion, it is attached to the tape-shaped optical fiber core wire 8. Further, reference numeral 7 indicates an insertion opening into which the protective boot 9 is inserted.

[0004]

In the above-mentioned conventional method for manufacturing an optical connector, it takes a lot of time and technique to polish the tip surface of the ferrule 1 to be performed lastly, which is a major factor in reducing the cost of the optical connector. It was an obstacle. Therefore, recently, a method has been studied in which it is not necessary to polish the tip surface of the ferrule (the same as the connection end surface of the multi-fiber optical connector). The point of realizing this method is to adjust the tip position by moving the tip of the optical fiber back and forth so that the tip of the ferrule and the tip of the optical fiber inserted into it match accurately. . Specifically, JP-A-1
There is a method described in Japanese Patent Publication No. 77003. In this method, for example, as shown in FIG. 10, while observing the tip of the ferrule 1 with a microscope 11, the tip of the optical fiber 4 protruding from the tip surface of the ferrule 1 is gripped by the tape-shaped optical fiber core wire 8. The core wire holder 13 is moved by moving it back and forth, and the tip position is adjusted by the micrometer 12 or the like. Although this method can be adjusted with high accuracy, it has a problem that it takes a long time for adjustment.

In the method disclosed in Japanese Patent Laid-Open No. 3-131805, the tip surface of the ferrule 1 is pressed against a reference surface 15 having a flat surface as shown in FIG. After injecting a required amount into the injection port 6, the optical fiber 4 is inserted into the optical fiber insertion hole 3 of the ferrule 1, and the tip end surface thereof is pressed against the reference surface 15 for positioning, and in this state, the ferrule 1 and the optical fiber 4 are inserted. In the same manner as shown in FIG. 9, and are bonded and integrated with the adhesive 10. This method has the advantages that the work is simpler and the adjustment time can be greatly shortened compared to the method described above. However, this method cannot confirm whether the tip end surface of the optical fiber is actually pressed against the reference surface 15, and the optical fiber 4 is further attached to the optical fiber insertion hole 3 of the ferrule 1.
Since the dust in the insertion hole 3 is moved forward while being attached to the tip surface thereof, the dust 16 is pressed against the reference surface 15 with the tip 16 attached thereto as shown in FIG. There is also the problem of being lost. In this case, garbage 1
The tip of the optical fiber 4 is the ferrule 1 by the thickness of 6
Since the optical connector is bonded and fixed at a position retracted from the front end surface of the optical connector, good connection characteristics cannot be obtained with such an optical connector.

[0006]

Therefore, in the present invention, there is provided a method for manufacturing an optical connector which does not require polishing and which solves the above-mentioned problems and which has a higher precision and a lower cost. The purpose is to In order to achieve the above object, the method for producing an optical connector of the present invention is such that the tip of the optical fiber core wire with the coating removed is inserted into an optical fiber insertion hole provided in a ferrule for an optical connector, and the tip surface is The step of projecting from the tip surface of the ferrule for optical connector, the step of cleaning the tip surface of the projected optical fiber core wire, and the step of abutting the tip surface of the cleaned optical fiber core wire against the reference surface A step of aligning the tip end surface of the wire with the tip end surface of the ferrule for the optical connector or positioning at a fixed distance from the tip end surface of the ferrule; and an adhesive for the positioned optical fiber core wire and the ferrule for the optical connector. And a fixing step.

[0007]

According to the present invention thus configured, the tip of the optical fiber is once projected from the tip surface of the ferrule, and then the reference surface is used to push the tip surface of the optical fiber back to the ferrule tip surface side. Since the positioning is performed with respect to the surface, the concern that the tip of the optical fiber is not pressed against the reference surface, which was a concern in the conventional method, is eliminated. Further, since the tip end surface of the optical fiber once projected is cleaned by, for example, blowing clean air, it is assumed that dust attached inside the optical fiber insertion hole of the ferrule adheres to the tip end surface of the optical fiber. Can also be removed by this cleaning, and when the tip surface of the optical fiber is pressed against the reference surface, the tip of the optical fiber recedes from the reference surface by the thickness of the dust.
There is no fear of that. As a result, it is possible to obtain an optical connector that is easy to work and has excellent connection characteristics at a low price.

[0008]

Embodiments of the present invention will be described in detail with reference to the drawings. First, FIG. 1 shows an optical fiber insertion jig used in the present invention. FIG. 1A is a side view and FIG. 1B is a plan view. In FIG. 1, reference numeral 20 is a main body of an optical fiber insertion jig, 13
Is a core wire holder for holding the tape-shaped optical fiber core wire 8,
Reference numeral 21 is a holding member that holds the ferrule 1 and the member 22 having the reference surface. Note that FIG. 1 shows an example in which a reference ferrule is used as the member 22 having the reference surface.

Further, the main body 20 of the optical fiber inserting jig.
A height adjusting portion 23 made of a screw or the like is provided at a lower portion of the rear end of the main body 20 so that the inclination of the main body 20 in the front-rear direction can be adjusted. Further, the holding member 21 and the main body 20 are joined by a joining jig 24 such as a hinge, and the holding member 21 is rotatable in the arrow A direction. Then, the gap between the ferrule 1 and the member 22 having the reference surface, or the contact pressure between the two is adjusted by the gap adjusting member 25 also made of a screw or the like. The holding member 21 and the main body 20 are rotatably joined by the joining jig 24.
As shown in (a), when the optical fiber 4 is attached to the ferrule 1, first, the holding member 21 is tilted downward so that the tip of the ferrule 1 is tilted downward so that the tip of the optical fiber 4 can be easily inserted into the ferrule 1. Then, as shown in FIG. 2 (b), the tip of the ferrule 1 is then raised upward so that the tip of the optical fiber 4 rubs the bottom surface of the ferrule 1, and the optical fiber insertion hole 3 2 and guide it so that the ferrule 1 and the optical fiber 4 are bonded to each other with an adhesive, and the adhesive is applied from the adhesive injection port 6 of the ferrule 1 to the ferrule 1 and the optical fiber 4. I try not to leak it. In this way, a series of work is facilitated. In addition, as described later, in order to clean the tip end surface of the optical fiber protruding from the tip end surface of the ferrule 1,
Although a cleaning jig such as an air cleaner is used, it is omitted in FIG.

The procedure for manufacturing the optical connector according to the present invention will be described in detail with reference to FIG. However, the above-mentioned optical fiber inserting jig itself used is omitted from the drawing, and the movement of the ferrule 1 in the holding member 21 and the member 22 having the reference surface, specifically, the reference ferrule will be described. First, FIG. 3 (a)
As shown in FIG. 3, the tape-shaped optical fiber core wire 8 and the primary coating of the optical fiber 4 are removed by a necessary length to expose the optical fiber 4, and the optical fiber insertion jig shown in FIG. It is fixed by the provided core wire holder 13. On the other hand, the gap between the ferrule 1 mounted in the holding member 21 and the member 22 having the reference surface which is previously mounted in the holding member 21 (hereinafter referred to as the reference ferrule in the description of FIG. 3) is set to the space adjusting member. As shown in FIG. 3 (b), the two are positioned by 25 with a predetermined gap therebetween.

Next, the core wire holder 13 is moved to the holding member 21, and the optical fiber 4 is attached to the ferrule 1 by the procedure shown in FIGS. 2 (a) to 2 (c). As described above, the tip end surface of the optical fiber 4 is slightly projected from the tip end surface of the ferrule 1. Although not shown,
When the optical fiber 4 is inserted into the optical fiber insertion hole 3 by slightly injecting the adhesive 10 from the adhesive injection port 6 in the state of FIG. 3B, the adhesive 10 is on the surface of the optical fiber 4. It may be inserted into the insertion hole 3 in a state of being attached to the. In this way, the adhesive 10 is reliably and uniformly interposed between the inner wall of the insertion hole 3 and the surface of the optical fiber 4, so that the optical fiber 4 is securely adhered and fixed to the ferrule 1, and in this way. When the obtained optical connector is subjected to a heat cycle, the contraction and expansion of the adhesive 10 become uniform in the circumferential direction of the optical fiber 4, so that there is an advantage that the connection characteristics are less deteriorated.

Subsequently, in FIG. 3C, the ferrule 1
Clean air is blown onto at least the tip end surface of the optical fiber 4 protruding from the tip end surface thereof by using a cleaning jig 30 such as an air cleaner. As a result, even if dust is attached to the tip portion including the tip surface of the optical fiber 4, this dust is removed. After this cleaning is completed, as shown in FIG. 3D, the member 22 having the reference surface, specifically, the reference surface of the reference ferrule is pressed against the tip surface of the ferrule 1 by the interval adjusting member 25. At this time, the front end surface of the optical fiber 4 protruding from the front end surface of the ferrule 1 is pushed back toward the ferrule 1 side, and the front end surface of the ferrule 1 and the front end surface of the optical fiber 4 coincide with each other.

In this state, as shown in FIG. 3 (e), the adhesive 10 is injected from the adhesive injection port 6 of the ferrule 1 until the outer surface of the ferrule 1 substantially coincides with the upper surface of the ferrule 1 and is cured. The optical fiber 4 and the ferrule 1 are bonded and fixed. 3 (d) to 3 (e), if the entire optical fiber insertion jig is tilted forward as shown in FIG. 1 (a), the optical fiber 4 will be the reference of the member 22 having the reference surface due to its own weight. Since it is pressed against the surface side, it is possible to maintain the state in which the tip end surface of the optical fiber 4 is surely in contact with the reference surface. When the above procedure is completed, the space adjusting member 25 is operated to retract the member 22 having the reference surface, and the core wire holder 13 on the main body 20 side of the optical fiber insertion jig is opened to open the tape-shaped optical fiber core wire 8. Along with, take out ferrule 1. In this way, an optical connector that does not require polishing of the tip surface of the ferrule 1 can be obtained.

In the optical connector obtained as described above, the projection length of the tip of the optical fiber 4 from the tip surface of the ferrule 1 is determined by the conventional method, specifically, Japanese Patent Laid-Open No. 3-1318.
Comparison was made with that of the optical connector obtained by the method described in Japanese Patent Publication No. 05 (the method shown in FIG. 11). FIG. 4 shows the results. In FIG. 4, the horizontal axis represents the protrusion length and the vertical axis represents the frequency. If the protrusion length is negative, the optical fiber 4
Indicates that the distal end surface of is retracted from the distal end surface of the ferrule 1 toward the inside of the ferrule 1. As shown in FIG. 4, the protrusions obtained by the conventional method have a wide projection length, specifically, in the range of -80 μm to +5 μm, but in the method of the present invention, the protrusion length is in the range of -5 μm to +5 μm. It is subdued and its variation is extremely small.
That is, it can be seen that the quality is extremely stable.

In the above-described embodiments, only the example in which the front end surface of the optical fiber 4 and the front end surface of the ferrule 1 are made to coincide with each other has been described, but the present invention sets the front end surface of the optical fiber 4 from the front end surface of the ferrule 1. It can also be applied to the case of manufacturing an optical connector of a type in which a certain length of protrusion is made. In this case, in FIG. 3D described above, when the tip surface of the optical fiber 4 is pushed back to the tip surface side of the ferrule 1 by the member 22 having the reference surface, the reference surface of the member 22 having the reference surface is set to the ferrule 1 side. It is sufficient to stop pressing the tip end surface of the ferrule 1 at a distance from the tip end surface of the ferrule 1 by an amount that the tip end surface of the optical fiber 4 is to be projected from the tip end surface of the ferrule 1. Therefore, in this case, FIG.
In the state of (c), the protrusion length of the front end surface of the optical fiber 4 from the front end surface of the ferrule 1 is finally determined by the optical fiber 4
The tip surface of the ferrule 1 is made to project a little longer than the tip surface of the ferrule 1, and the member 2 having the reference surface is formed.
It is important to push back the front end surface of the optical fiber 4 to the front end surface side of the ferrule 1 to some extent by the reference surface of 2.

Another embodiment of the present invention will be described below. 5 (a) and 5 (b) are a side view and a plan view of another optical fiber insertion jig used in the present invention. 1 is different from that shown in FIG. 1 in that the member 22 having a reference surface is not a reference ferrule but a glass plate or a metal plate having a flat plane, and that the permanent magnet 31 is used to have magnetism. The core wire holder 13 made of metal, specifically iron, is pulled toward the member 22 having the reference surface, whereby the optical fiber 4 is pressed against the reference surface of the member 22 having the reference surface. As described above, in the structure shown in FIG. 1, the rear end portion of the main body 20 of the optical fiber insertion jig is made higher than the front end portion by the height adjusting portion 23, and the front end surface of the optical fiber 4 is caused by the weight of the optical fiber 4. Although it is pressed against the reference surface of the reference ferrule, if the core wire holder 13 is forcibly pulled by the permanent magnet as shown in FIG. 5, the tip end surface of the optical fiber 4 is more reliably fixed to the reference surface of the member 22 having the reference surface. Can be pressed against.

FIGS. 6A and 6B show another method for cleaning the front end surface of the optical fiber 4 which is projected from the front end surface of the ferrule 1. Although the air cleaner is used as the cleaning jig 30 in FIG. 3, the cleaning jig 30 shown in FIG. 6B is an example in which the cleaning jig 30 is made of a clean cotton swab or the like. Any method including that shown in FIG. 3 may be adopted.

FIGS. 7A to 7E show other examples of the member 22 having a reference surface. FIG. 6 is a plan view showing a state in which the holding member 21 is mounted in FIGS. 1 and 5, respectively. 7 (a) to 7 (c) are provided with, as a reference surface of the member 22 having a reference surface, a protrusion 40 whose tip is the reference surface according to the number and pitch of the optical fibers 4. 7A shows a columnar shape, FIG. 7B shows a truncated cone shape, and FIG. 7C shows a spherical tip. Further, in the case of FIG. 7D, a concave portion 50 is provided so that the reference surface is not easily scratched, and the concave portion 50 is used as the reference surface.
Further, the one shown in FIG.
The projection 40 shown in (a) is provided. The reason for providing the protrusions 40 is to reduce the area of the reference surface that requires precision as much as possible, improve the precision of machining, and reduce the cost of machining.

[0019]

According to the present invention as described above,
Manufacture an optical connector, especially a multi-fiber optical connector with multiple optical fibers attached, which does not require polishing of the ferrule tip surface after the optical fibers are attached, easily, accurately and at low cost. it can.

[0020]

[Brief description of drawings]

FIG. 1 is a side view and a plan view showing an optical fiber insertion jig used in the present invention and a state in which a member having a ferrule and a reference surface is attached to the jig.

FIG. 2 is an explanatory diagram showing a procedure for mounting an optical fiber on a ferrule with the optical fiber insertion jig shown in FIG.

FIG. 3 is an explanatory diagram of an example showing a procedure of the present invention.

FIG. 4 is a diagram showing variations in the protruding length of the front end surface of the optical fiber from the front end surface of the ferrule in the optical connector manufactured by the present invention and the conventional method.

FIG. 5 shows another example of the optical fiber inserting jig used in the present invention, and is a side view and a plan view showing a state in which a ferrule and a member having a reference surface are attached thereto.

FIG. 6 is an explanatory view showing another example of the cleaning jig used in the present invention.

FIG. 7 is a plan view showing another example of a member having a reference surface used in the present invention.

FIG. 8 is a perspective view showing an example of an optical connector according to the present invention.

9 is a cross-sectional view of the optical connector shown in FIG.

FIG. 10 is an explanatory diagram showing a conventional method.

FIG. 11 is an explanatory diagram showing another conventional method.

FIG. 12 is an explanatory diagram illustrating a problem of the conventional method shown in FIG. 11.

[Explanation of symbols]

 1 ferrule 3 optical fiber insertion hole 4 optical fiber 6 adhesive injection port 8 tape-shaped optical fiber core wire 10 adhesive 13 core wire holder 20 optical fiber insertion jig 21 holding member 22 member having a reference surface 24 coupling jig 25 spacing Adjustment member 30 Cleaning jig 40 Protrusion

Claims (1)

[Claims] 1. A tip portion of an optical fiber core wire from which a coating is removed is inserted into an optical fiber insertion hole provided in a ferrule for an optical connector, and the tip surface is projected from the tip surface of the ferrule for the optical connector. A step of cleaning the tip end surface of the projected optical fiber core wire, and abutting the tip end surface of the cleaned optical fiber core wire against a reference surface so that the end surface of the optical fiber core wire is the ferrule for the optical connector. Of the optical connector, and a step of positioning the optical fiber core wire and the ferrule for the optical connector by using an adhesive agent. Method.