JP3931441B2 - Optical connector assembly method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical connector assembling method having an optical fiber mounting step in which an optical fiber is projected by a predetermined amount from a front end face of a ferrule by polishing when mounting the optical fiber on a ferrule.
[0002]
[Prior art]
Conventionally, as a technique in such a field, there is JP-A-6-222247. This publication discloses an optical connector that can be connected to a PC. As a method of assembling this optical connector, first, a spacer pin is inserted into the guide pin hole of the ferrule, and in that state, the optical fiber is connected until reaching the spacer. Continue to polish the tip. As a result, the tip end surface of the optical fiber can be protruded from the front end surface of the ferrule with the thickness of the spacer main body.
[0003]
[Problems to be solved by the invention]
However, the above-described conventional optical connector assembling method has the following problems. In other words, when the tip of the optical fiber is protruded by a predetermined amount from the front end face of the ferrule, it is necessary to be careful not to scrape the front end face of the ferrule when polishing the front end face of the optical fiber. High-precision polishing control is required so that excessive cutting of the portion does not occur. As a result of the necessity of the spacer, the assembly work is complicated.
[0004]
The present invention has been made to solve the above-described problems, and in particular, provides an optical connector assembling method that facilitates control of the amount by which the tip portion of the optical fiber protrudes from the front end surface of the ferrule. The purpose is to do.
[0005]
[Means for Solving the Problems]
The optical connector assembling method of the present invention according to claim 1 includes inserting an optical fiber from the rear into an optical fiber insertion portion extending inward from an optical connection port formed on the front end surface of the ferrule, and the tip of the optical fiber. In an optical connector assembly method comprising an optical fiber mounting step of polishing a tip end surface of an optical fiber and projecting a predetermined amount of optical fiber from the front end surface of the ferrule with the portion protruding from the front end surface of the ferrule.
The front end surface of the ferrule has a first reference surface that extends including the optical connection port, and a second reference surface that extends forward and protrudes from the first reference surface. Is a non-polished surface, and the second reference surface is formed as a polishing reference surface,
In the optical fiber mounting process, an optical fiber that protrudes from the front end surface of the ferrule while facing the polishing surface parallel to the second reference surface and relatively bringing the polishing surface and the front end surface of the ferrule closer to each other The polishing surface is polished with the polishing surface, and the polishing surface is brought into contact with the second reference surface of the ferrule during the polishing of the optical fiber so that the optical fiber protrudes from the first reference surface. stopping polishing of the second reference surface of the ferrule by, characterized Rukoto that the distal end surface of the second reference surface and the optical fiber aligning on the same plane.
[0006]
The ferrule used in this optical connector assembling method is a ferrule scheduled to be used for PC connection. In the optical fiber mounting process using the ferrule, first, the optical fiber is inserted into the optical fiber insertion portion of the ferrule from the rear, and the tip of the optical fiber is projected from the front end face of the ferrule. Then, the optical fiber is polished by the polishing surface of the polishing jig until the optical fiber reaches a predetermined protruding amount. When starting the polishing, the relative positional relationship between the polishing surface of the polishing jig and the front end surface of the ferrule is determined with reference to the second reference surface, and the polishing surface is determined with respect to the second reference surface of the ferrule. Set to be parallel. After the setting, the tip surface of the optical fiber is continuously polished while the polishing surface and the front end surface of the ferrule are relatively close to each other. At this time, the polishing surface polishes only the front end surface of the optical fiber, but the polishing during this time is performed at a high speed. Then, at the same time when the polishing surface reaches the second reference surface of the ferrule, the polishing rate per unit length of the optical fiber rapidly decreases due to the rapid expansion of the polishing area. As a result, in an optical connector that is required to control the protruding amount of the optical fiber on the order of microns, time control for stopping the polishing operation becomes simple. In addition, the position of the tip surface of the optical fiber and the position of the second reference surface can always be aligned on the same plane.
[0007]
In the optical connector assembling method according to claim 2, it is preferable that the front end surface of the ferrule extends in parallel between the first reference surface and the second reference surface via a stepped portion. If it does in this way, the protrusion amount of an optical fiber can be easily controlled by the amount of level | step differences.
[0008]
In the optical connector assembling method according to claim 3, it is preferable that the front end surface of the ferrule has a first reference surface as an inclined surface and the first reference surface and the second reference surface extend continuously. In this way, the protruding amount of the optical fiber can be easily controlled by changing the boundary position between the first reference surface and the second reference surface.
[0009]
In the optical connector assembling method according to claim 4, it is preferable that the front end surface of the ferrule has a first reference surface as a curved surface and the first reference surface and the second reference surface extend continuously. In this way, the protruding amount of the optical fiber can be easily controlled by changing the boundary position between the first reference surface and the second reference surface.
[0010]
In the method of assembling the optical connector according to claim 5, it is preferable to chamfer the edge portion of the front end surface of the optical fiber protruding from the front end surface of the ferrule. When such a method is adopted, when the ferrules are brought into contact with each other for PC connection, chipping of the tip of the optical fiber can be prevented appropriately.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of an optical connector assembling method according to the present invention will be described in detail with reference to the drawings.
[0012]
FIG. 1 is a perspective view showing an optical connector. The optical connectors 2 and 3 shown in the figure are configured as plugs of a push-on / pull-off connector (for example, MPO connector) 1 and have a structure for realizing PC (Physical Contact) connection, and are simply pushed into the adapter 4. Enables one-touch connection. The optical connectors 2 and 3 can be easily detached from the adapter 4 by pulling out the ejectors 5 of the optical connectors 2 and 3 with fingers. The optical connector 2 has a sleeve-like housing 6 made of plastic, and a ferrule 7 is accommodated in the housing 6.
[0013]
As shown in FIG. 2, the ferrule 7 is formed of an epoxy resin filled with glass fine particles (glass filler) in order to make the coefficient of thermal expansion close to that of the optical fiber 8 in the optical fiber core wire 12. As shown in FIG. 3, the ferrule 7 is provided with a hole-like optical fiber insertion portion 11 extending inward from each of the four optical connection ports 10 formed on the front end surface 9. In each optical fiber insertion portion 11, four optical fibers 8 exposed by removing the coating from the tip of the optical fiber core wire 12 are inserted, and each optical fiber 8 is inserted into each optical fiber insertion portion 11 by an adhesive. Or it fixes with the optical connection port 10. FIG. The tip of each optical fiber 8 protrudes from the front end face 9 of the ferrule 7 by a predetermined length, thereby enabling PC connection. Further, the ferrule 7 is provided with guide pin holes 13 for inserting guide pins P (see FIG. 1), and the guide pin holes 13 are located on both sides of the optical connection port 10.
[0014]
Here, as shown in FIG. 4, the front end surface 9 of the ferrule 7 protrudes forward from the first reference surface 14 that extends as a surface including the optical connection port 10 and the first reference surface 14. And a second reference surface 15 extending. The second reference surface 15 is formed at an angle of 90 degrees with respect to the flat upper surface 7A of the ferrule 7 extending in parallel with the axis K of the optical fiber insertion portion 11, and this surface serves as a polishing reference surface. Used. That is, the relative positional relationship between the polishing surface 20a of the polishing board 20 fixed to the rotating shaft A of the motor M and the front end surface 9 of the ferrule 7 is determined with reference to the second reference surface 15, and the polishing surface 20a It is set so as to be parallel to the second reference plane 15.
[0015]
In a state where the optical fiber 8 is mounted on the ferrule 7, the ferrule 7 is set on the ferrule chuck portion 101 of the polishing jig 100 shown in FIG. 5, and in the polishing operation of the front end surface 9 of the ferrule 7, the ferrule 7 is always used. The second reference surface 15 of the front end surface 9 and the polishing surface 20a of the polishing disk 20 are parallel to each other. The polishing jig 100 is disclosed in Japanese Patent Application Laid-Open No. 7-251363, and it goes without saying that this is an example of the polishing jig.
[0016]
In addition, as shown in FIG. 4, the first reference surface 14 extends with respect to the second reference surface 15 with an inclination angle α (for example, 1 to 2 degrees), and also with respect to the second reference surface 15. In a continuous state. The first reference surface 14 is retracted with respect to the second reference surface 15 and is a non-polished surface that does not come into contact with the polished surface 20a. As a result of adopting the structure of the ferrule 7 as described above, when assembling the optical connector 1 that can be connected to a PC, the tip of each optical fiber 8 protrudes from the front end face 9 of the ferrule 7 by a desired amount as shown in FIG. Can be made. Note that the amount of protrusion of the optical fiber 8 can be easily controlled by changing the boundary position between the first reference surface 14 and the second reference surface 15.
[0017]
Next, an optical fiber mounting process will be described. First, the tip of each optical fiber 8 is inserted from the rear of each optical fiber insertion portion 11 of the ferrule 7, and the tip of each optical fiber 8 is projected from the first reference surface 14 of the ferrule 7 by a predetermined amount. In this case, all the tips of the optical fibers 8 are pushed in until they protrude from the protruding reference plane S formed on the extension of the second reference plane 15, and the optical fibers 8 are fixed to the ferrule 7 with an adhesive. .
[0018]
Thereafter, the ferrule 7 is set on the ferrule chuck portion 101 of the polishing jig 100 of FIG. Then, as shown in FIG. 7, the polishing surface 20 a of the polishing plate 20 fixed to the rotation shaft A of the motor M and the second reference surface 15 of the front end surface 9 of the ferrule 7 are opposed to each other in parallel. Thereafter, while rotating the rotating shaft A of the motor M, the tip surface 8a of the optical fiber 8 is continuously polished by the polishing surface 20a while bringing the ferrule 7 close to the polishing surface 20a. At this time, the polishing surface 20a polishes only the front end surface 8a of the optical fiber 8, but the polishing during this time is performed at a high speed per unit length of the optical fiber 8 as indicated by reference numeral a in FIG.
[0019]
After that, as shown in FIG. 6, the polishing surface 20a reaches the second reference surface 15, and at the same time, the polishing area rapidly increases. As a result, the polishing rate per unit length of the optical fiber 8 is abruptly lowered as indicated by the symbol b in FIG. As described above, when controlling the protruding amount of the optical fiber 8 on the micron order, the protruding amount of the optical fiber 8 is controlled while polishing the ferrule 7, so that only the optical fiber 8 is polished and the protruding amount of the optical fiber 8 is reduced. Compared to the control, the polishing time can be controlled very easily, and it is possible to provide a time margin for the control to stop the polishing operation. As shown in FIG. Even if there is a variation, the desired protrusions aligned in a row are reliably controlled. Further, after the point when the polishing surface 20a hits the second reference surface 15, the tip surface 8a of the optical fiber 8 is always located in the protruding reference plane S at the same position as the polishing surface 20a, and the second reference surface 15 and the front end surface 8a of the optical fiber 8 are aligned on the same protruding reference plane S.
[0020]
Accordingly, when the polishing operation is stopped in a state where the polishing surface 20a is polishing the second reference surface 15, the tip surface 8a of the optical fiber 8 does not protrude forward from the second reference surface 15, and the protrusion reference located in the flat plane S, so that only project by a certain amount from the first reference surface 14 (e.g., about 0.02 mm). Thus, the second reference surface 15 is used as a reference surface when determining the protruding amount of the optical fiber 8, and the protruding amount of the optical fiber 8 is controlled with the polishing time.
[0021]
The size of the angle α is also an important factor in determining the amount of protrusion of the optical fiber 8, and the larger the angle α is, the larger the amount of protrusion of the optical fiber 8 from the first reference plane 14 can be. Needless to say. Further, as shown in FIG. 10, the tip surface 8a of each optical fiber 8 is appropriately chamfered to prevent the tip surface 8a from being chipped. For example, when an alumina solvent having a particle size of 1 μm is dropped on a velvet cloth and the tip face 8a of the optical fiber 8 is polished with this cloth, the tip face 8a is rounded and the edge is chamfered. As an effect of performing such a chamfering process, a work-affected layer generated during the polishing of the front end face 8a of the optical fiber 8 can be removed, and in the experiment, a return loss of 40 dB or more was confirmed.
[0022]
The ferrule applied to the optical connector assembling method according to the present invention is not limited to the above-described one.
[0023]
For example, as shown in FIG. 11, the front end surface 31 of the ferrule 30 includes a first reference surface 33 extending as a surface including the optical connection port 10 provided at the front end portion of the optical fiber insertion portion 11, and this And a second reference surface 34 that protrudes and extends forward from the first reference surface 33. The second reference surface 34 is formed with an inclination angle β of 82 degrees with respect to the flat upper surface 30A of the ferrule 30 extending parallel to the axis K of the optical fiber insertion portion 11, and this surface is a reference surface for polishing. Used as The reason why the angle β is set to 82 degrees is to make the front end face 8a of the optical fiber 8 an inclined face of 8 degrees after polishing in consideration of the reflected return light at the front end face 8a of the optical fiber 8. Further, the first reference surface 33 extends with an inclination angle α (for example, 1 to 2 degrees) with respect to the second reference surface 34 and is formed in a continuous state with respect to the second reference surface 34. ing. Then, as a result of the first reference surface 33 retreating with respect to the second reference surface 34, the first reference surface 33 becomes a non-polishing surface with which the polishing surface 20a does not contact. As a result of adopting such a ferrule 30 structure, the tip of each optical fiber 8 can be projected from the front end face 31 of the ferrule 30 by a desired amount during assembly of an optical connector that can be connected to a PC.
[0024]
As another modification of the ferrule, as shown in FIG. 12, the front end surface 51 of the ferrule 50 extends as a surface including the optical connection port 10 provided at the front end portion of the optical fiber insertion portion 11. A reference surface 53 and a second reference surface 54 projecting forward from the first reference surface 53 and extending. The second reference surface 54 is formed at an angle of 90 degrees with respect to the flat upper surface 50A of the ferrule 50 extending in parallel with the axis K of the optical fiber insertion portion 11, and this surface is used as a polishing reference surface. Is done. The first reference surface 53 extends in parallel with the second reference surface 54 and is connected to the second reference surface 54 via a stepped portion 52 having a predetermined step amount γ. Further, as a result of the first reference surface 53 retreating with respect to the second reference surface 54, the first reference surface 53 becomes a non-polishing surface with which the polishing surface 20a does not contact. As a result of adopting the structure of the ferrule 50 as described above, the end of each optical fiber 8 can be protruded by a desired amount from the front end face 51 of the ferrule 50 during the assembly work of the optical connector that can be connected to the PC.
[0025]
As yet another modification of the ferrule, as shown in FIG. 13, the front end surface 71 of the ferrule 70 extends as a surface including the optical connection port 10 provided at the front end portion of the optical fiber insertion portion 11. And a second reference surface 74 that protrudes forward from the first reference surface 73 and extends. The second reference surface 74 is formed with an inclination angle β of 82 degrees with respect to the flat upper surface 70A of the ferrule 70 extending in parallel with the axis K of the optical fiber insertion portion 11, and this surface is a polishing reference surface. Used as The reason why the angle β is set to 82 degrees is to form the front end face 8a of the optical fiber 8 with an inclined face of 8 degrees after polishing in consideration of the reflected return light at the front end face 8a of the optical fiber 8. . The first reference surface 73 extends in parallel with the second reference surface 74 and is connected to the second reference surface 74 via a stepped portion 72 having a predetermined step amount γ. Then, as a result of the first reference surface 73 moving backward with respect to the second reference surface 74, the first reference surface 73 becomes a non-polishing surface with which the polishing surface 20 a does not contact. As a result of adopting the structure of the ferrule 70 as described above, the end of each optical fiber 8 can be protruded from the front end face 71 of the ferrule 70 by a desired amount at the time of assembling the optical connector that can be connected to a PC.
[0026]
The ferrule applied to the assembling method of the present invention is not limited to those of the above-described embodiments. For example, in the ferrule 90 as shown in FIG. 14, the second reference surface 92 is formed as a flat surface, One reference surface 91 may be formed of a curved surface, and a chamfered portion 95 for preventing chipping is provided on the second reference surface 94 side of the ferrule 93 as shown in FIG. It may be. A chamfered portion (not shown) may be provided on the curved first reference surface 96 side.
[0027]
Note that the above-described optical connector for PC connection includes an MT connector and an MPO connector. Further, the optical fiber 8 to be mounted on the optical connector has a single core and is not limited to the above-described number of cores.
[0028]
【The invention's effect】
The optical connector assembling method according to the present invention has the following effects. That is, in the state where the optical fiber is inserted from the back into the optical fiber insertion portion extending inward from the optical connection port formed on the front end surface of the ferrule, and the front end portion of the optical fiber protrudes from the front end surface of the ferrule, In an optical connector assembly method comprising an optical fiber mounting step of polishing a front end surface of an optical fiber and projecting a predetermined amount of optical fiber from a front end surface of a ferrule,
The front end surface of the ferrule has a first reference surface that extends including the optical connection port, and a second reference surface that extends forward and protrudes from the first reference surface. Is a non-polished surface, and the second reference surface is formed as a polishing reference surface,
In the optical fiber mounting process, an optical fiber that protrudes from the front end surface of the ferrule while facing the polishing surface parallel to the second reference surface and relatively bringing the polishing surface and the front end surface of the ferrule closer to each other The polishing surface is polished with the polishing surface, and the polishing surface is brought into contact with the second reference surface of the ferrule during the polishing of the optical fiber so that the optical fiber protrudes from the first reference surface. Control of the amount by which the tip portion of the optical fiber protrudes from the front end surface of the ferrule by stopping polishing of the second reference surface of the ferrule by the step and aligning the second reference surface and the tip surface of the optical fiber on the same plane To make it easier.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an embodiment of an optical connector assembled by an optical connector assembling method according to the present invention.
FIG. 2 is a perspective view showing a first embodiment of a ferrule applied to an optical connector assembling method according to the present invention.
3 is a cross-sectional view of the ferrule shown in FIG.
4 is an enlarged side view of a main part of the ferrule shown in FIG. 3. FIG.
FIG. 5 is a perspective view showing a polishing jig used in the optical connector assembling method according to the present invention.
6 is an enlarged side view of a main part showing a state after polishing of an optical fiber mounted on the ferrule shown in FIG. 3; FIG.
7 is an enlarged side view of a main part showing a state in which the optical fiber mounted on the ferrule shown in FIG. 3 is being polished. FIG.
FIG. 8 is a diagram showing a relationship between a protruding length of an optical fiber and a polishing time.
FIG. 9 is a front view showing that the optical fibers protruding from the front end face of the ferrule are in an irregular state.
FIG. 10 is an enlarged front view showing a state of a front end surface of an optical fiber protruding from a front end surface of the ferrule.
FIG. 11 is an enlarged side view of an essential part showing a second embodiment of a ferrule applied to the optical connector assembling method according to the present invention.
FIG. 12 is a principal side enlarged side view showing a third embodiment of a ferrule to be applied to the optical connector assembling method according to the present invention.
FIG. 13 is an enlarged side view of an essential part showing a fourth embodiment of a ferrule applied to an optical connector assembling method according to the present invention.
FIG. 14 is a principal side enlarged side view showing a fifth embodiment of a ferrule to be applied to the optical connector assembling method according to the present invention.
FIG. 15 is a principal side enlarged side view showing a sixth embodiment of a ferrule to be applied to the optical connector assembling method according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 2,3 ... Optical connector, 7, 30, 50, 70, 90, 93 ... Ferrule, 8 ... Optical fiber, 8a ... Front end surface of optical fiber, 9, 31, 51, 71 ... Front end surface, 10 ... Optical connection port , 11 ... optical fiber insertion portion, 14, 33, 53, 73, 91, 96 ... first reference surface, 15, 34, 54, 74, 92, 94 ... second reference surface, 20a ... polished surface, 100 ... a polishing jig.

Claims (5)

In the state where the optical fiber is inserted from the rear into the optical fiber insertion portion extending inward from the optical connection port formed on the front end surface of the ferrule, and the tip portion of the optical fiber is projected from the front end surface of the ferrule, In an optical connector assembly method comprising an optical fiber mounting step of polishing a front end surface of the optical fiber and projecting a predetermined amount of optical fiber from the front end surface of the ferrule,
The front end surface of the ferrule has a first reference surface extending including the optical connection port, and a second reference surface extending forward and projecting from the first reference surface, The first reference surface is a non-polishing surface and the second reference surface is a polishing reference surface.
In the optical fiber mounting step, the front end of the ferrule is placed while facing the polishing surface parallel to the second reference surface and relatively bringing the polishing surface and the front end surface of the ferrule closer together. The tip surface of the optical fiber protruding from the surface is polished by the polishing surface, and the polishing surface is brought into contact with the second reference surface of the ferrule during the polishing of the optical fiber. In a state of protruding from the first reference surface, polishing of the second reference surface of the ferrule by the polishing surface is stopped , and the second reference surface and the tip surface of the optical fiber are flush with each other. method of assembling an optical connector according to claim Rukoto align with. 2. The optical connector assembling method according to claim 1, wherein the front end surface of the ferrule extends in parallel with the first reference surface and the second reference surface through a step portion. The front end surface of the ferrule has the first reference surface as an inclined surface, and the first reference surface and the second reference surface extend continuously. To assemble optical connector. The front end surface of the ferrule has the first reference surface as a curved surface, and the first reference surface and the second reference surface extend continuously. To assemble optical connector. The optical connector assembling method according to any one of claims 1 to 4, wherein chamfering is performed on an edge portion of the tip end surface of the optical fiber protruding from the front end surface of the ferrule.

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