JP3669329B2 - Manufacturing method of optical connector - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing an optical connector for connecting optical fibers.
[0002]
[Prior art]
In an optical connector for connecting optical fibers, in order to reduce reflection return light at the connection point, (1) a method in which a refractive index matching agent having the same refractive index as that of the core portion of the optical fiber is interposed between optical fiber end faces. And (2) a method using physical contact (PC coupling) in which end faces of optical fibers are directly contact-coupled to each other has been studied. The method using PC bonding is superior to the method using a refractive index matching agent in terms of workability and handling. For this reason, in order to realize PC coupling in recent years, methods for polishing an end face of an optical fiber have been studied.
[0003]
In a single-core connector, PC coupling is realized by a method such as processing a convex spherical surface of the optical connector ferrule end face. However, in a multi-fiber connector, it is necessary to collectively couple a plurality of optical fibers together. The difficulty level is high. As a method for connecting the multi-fiber connector to the PC, a polishing method for slightly protruding the optical fiber from the end face of the optical connector ferrule has been studied. For example, Japanese Patent Laid-Open No. 9-304657 discloses a polishing method in which an optical fiber is slightly protruded from an end face of an optical connector ferrule by using a difference in hardness between the optical fiber and the optical connector ferrule.
[0004]
FIG. 6 is a perspective view showing a conventional optical connector. A single mode type optical fiber 6 is inserted into each of four optical fiber insertion holes provided in the optical connector ferrule 201, and a pair of mating pins are inserted on both sides thereof to engage with other optical connector ferrules. A fitting pin insertion hole 203 is provided. The optical fiber 6 is included in the tape-shaped optical fiber core 204, and the tape-shaped optical fiber core 204 from which the coating at the tip is removed from the rear end portion of the optical connector ferrule 201 is inserted and used as an adhesive. And the optical connector 210 is obtained. The end face of the optical connector ferrule 210 and the end face of the single mode type optical fiber 6 are inclined at an angle of 8 ° as necessary to prevent the reflected return light of the light at the coupling face from entering the core of the optical fiber. . This optical connector is inserted into a plastic housing 41 as shown in FIG. 7 and is coupled to the opposing optical connector via two guide pins 43 by fitting into the adapter 42.
[0005]
In this conventional optical connector, the same type of optical fiber such as only a single mode type optical fiber or only a multimode type optical fiber is built in one optical connector ferrule. On the other hand, in recent years, the use of different types of optical fibers such as single-mode optical fibers, multi-mode optical fibers, dispersion-shifted fibers, dispersion-compensating fibers, and polarization-maintaining fibers is increasing. In particular, there are cases where a high-speed line and a low-speed line are mixed and used in a LAN, and a case where a single mode type optical fiber and a multimode type optical fiber are used simultaneously is increasing. In such a case, an optical cord containing only a single mode type optical fiber and an optical cord containing only a multimode type optical fiber were prepared separately, and an optical connector was attached to each. Therefore, the end face polishing could be performed separately for each optical connector ferrule with a built-in single mode type optical fiber and an optical connector ferrule with a built-in multimode type optical fiber under the optimum conditions.
[0006]
[Problems to be solved by the invention]
However, if an optical cord in which optical fibers having different structures and compositions are mixed and an optical connector that can be connected to the terminal is attached, optical fibers having different structures and compositions can be connected simultaneously by one optical connector. However, when polishing an optical connector with a mixture of optical fibers having different structures and compositions, the same silica-based optical fiber has different easiness to scrape due to the difference in structure and composition. The protruding length of the fiber from the end face of the optical connector ferrule is different, and when the optical connectors are butted together, the optical fibers having a small protruding length cannot be in contact with each other, and there is a problem that the whole core is not necessarily PC-coupled.
[0007]
In order to realize PC coupling, the optical fiber protrudes from the end face of the optical connector ferrule, and when there are a plurality of optical fibers, the variation in the protruding length of each optical fiber needs to be small. If the variation in the protruding length of each optical fiber is large, the optical fiber with a small protruding length will not be PC-coupled when the optical connector is abutted, and the connection loss of communication light at the end face of the optical fiber will be large, impeding communication. Will occur.
[0008]
In view of such circumstances, the present invention can polish so that the variation in the protruding length of each optical fiber can be reduced even if optical fibers having different structures and compositions are mixed in one optical connector, and the entire core PC It is an object of the present invention to provide an optical connector capable of realizing coupling, a cord with an optical connector, and a method for polishing the optical connector.
[0009]
In order to solve the above problems, an optical connector manufacturing method of the present invention includes a plurality of optical fiber insertion holes in an optical connector ferrule, two fitting pin insertion holes on both sides thereof, In a method for polishing and manufacturing an optical connector in which an optical fiber is inserted and fixed in each optical fiber insertion hole using a rotary polishing disk, the plurality of optical fibers are composed of two types of optical fibers having different hardness, The line connecting the center of the optical connector ferrule and the center of the polishing board on the contact surface of the connector ferrule with the polishing board and the line connecting the centers of the two fitting pin insertion holes are 60 ° or more and 120 ° or less. The optical connector ferrule is fixed on the polishing board so as to cross at an angle, and the polishing board is a hard optical fiber of two types of optical fibers having different hardness in the optical connector ferrule. The side where the bar is arranged rotates in an upstream direction.
[0010]
In the polished optical connector, the protruding length of the optical fiber from the end face of the optical connector ferrule at the end face is 1.5 μm or more and 4.0 μm or less, and the protruding length of the most protruding optical fiber and the shortest protruding optical fiber is The difference is preferably 0.3 μm or less, which makes it possible to realize stable PC coupling.
[0013]
In the optical connector of the present invention, a single mode type optical fiber is inserted as a hard optical fiber, and a multimode type optical fiber is inserted and fixed as a soft optical fiber, out of two types of optical fibers having different hardnesses inserted into the optical connector ferrule. It is effective in the case.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of the optical connector of the present invention. The optical connector ferrule 1 is made by resin molding, and is used to fit six optical fiber insertion holes for inserting optical fibers and other optical connector ferrules by inserting fitting pins (not shown). A pair of fitting pin insertion holes 3 are provided. A tape-like optical fiber core wire 4 from which the coating at the tip is removed from the rear end portion of the optical connector ferrule 1 is inserted and fixed with an adhesive.
[0017]
The tape-shaped optical fiber 4 includes four single-mode optical fibers 6 and two multi-mode optical fibers 7, and correspondingly, the optical connector ferrule 1 has four single-mode optical fibers 6. A mode type optical fiber 6 and two multimode type optical fibers 7 are arranged together in this order from one end. The end face of the optical connector ferrule 1 is polished with the six optical fibers protruding slightly.
[0018]
The material of the optical connector ferrule 1 is preferably a material having a hardness lower than that of an optical fiber and a high dimensional accuracy. A plastic material such as an epoxy resin containing silica powder and PPS (polyphenylene sulfide) is suitable. In the case of the optical connector 10 in which a quartz optical fiber is inserted into the optical connector ferrule 1 made of plastic, the hardness difference between the optical connector ferrule 1 and the optical fiber is larger than when ceramics or metal is used. The fiber can be easily protruded, and the effect of the present invention is remarkably exhibited.
[0019]
The number of single mode type optical fibers and multimode type optical fibers accommodated in the optical connector ferrule 1 is not limited as long as it is one or more. If it cannot be stored in one row, it may be arranged in two or more rows.
[0020]
FIG. 2 is a schematic diagram showing another preferred embodiment of a single mode type optical fiber that is a hard optical fiber and a multimode type optical fiber that is a soft optical fiber on the end face of the optical connector of the present invention. As shown in FIGS. 2A to 2C, a plurality of optical fibers arranged in a line have at least one single-mode optical fiber and multi-mode optical fiber, each of which is bundled. Has been placed. Also, as shown in (d), (g), and (h), in a plurality of optical fibers arranged in two or three rows, a single mode type optical fiber and a multimode type optical fiber are respectively arranged on the left and right sides. They may be arranged together. As shown in (i), the single mode type optical fiber and the multimode type optical fiber may be arranged together for each column. In addition, as shown in (e) and (f), a plurality of optical fibers may be arranged randomly, and a single mode type optical fiber and a multimode type optical fiber may be arranged together in the left and right or up and down directions. good.
[0021]
Optical fibers with different structures and compositions housed in optical connector ferrules include dispersion-shifted fibers, dispersion-compensating fibers, polarization-maintaining fibers, and erbium-doped fibers in addition to single-mode optical fibers and multi-mode optical fibers. Can be mentioned. Each is a silica-based optical fiber, but since the hardness is different, the ease of shaving when polishing is different, and the arrangement of each of them makes it possible to reduce the variation in the protruding length of each optical fiber. Examples of the hard optical fiber include a single mode optical fiber, a dispersion shifted fiber, and an erbium-doped fiber, and examples of the soft optical fiber include a multimode optical fiber and a polarization-maintaining fiber.
[0022]
A tape-shaped optical fiber is formed by integrating four single-mode optical fibers 6 and two multi-mode optical fibers 7, and the coating on one end or both ends is removed, and an optical connector is inserted and fixed. Thus, the cord with the optical connector of the present invention can be produced. If necessary, a plurality of tape-shaped optical fiber cores may be laminated, tensile strength fibers may be arranged on the outer periphery, and covered with a jacket made of plastic. Since different types of optical fibers can be connected simultaneously with one optical connector, the number of optical fiber cores and the number of optical connectors can be reduced, and the diameter of the optical cord can be reduced.
[0023]
The polished optical connector 10 preferably has a protruding length of the optical fiber from the end face of the optical connector ferrule 1 at the end face of 1.5 μm or more and 4.0 μm or less. When the protrusion length is 1.5 μm or less, when the optical connectors 10 are fitted together, the optical fibers cannot sufficiently contact each other and it is difficult to perform the PC coupling. When the protruding length is 4.0 μm or more, it is easy to apply an optical fiber when the optical connectors 10 are fitted together. It is preferable that the difference between the protruding length of the optical fiber 5 that protrudes most and the optical fiber that has the shortest protruding length is 0.3 μm or less. When the difference in protrusion length is 0.3 μm or more, it is difficult to PC-couple an optical fiber having a small protrusion length. The end face of the optical connector ferrule 1 and the end face of the optical fiber are 4 ° to 15 ° with respect to the plane orthogonal to the optical fiber optical axis in order to prevent the reflected return light of the light at the coupling face from entering the core of the optical fiber. It may be inclined at an angle of °.
[0024]
FIG. 3 shows a side view of a polishing apparatus used in the embodiment of the present invention. The optical connector 10 is set on the fixing jig 21 with its end face facing down. A polishing film 23 is affixed on the polishing board 22, and the end face of the optical connector ferrule 1 is pressed against the polishing film with a constant load. The polishing film 23 is polished while dropping a polishing liquid in which abrasive grains are suspended.
[0025]
FIG. 4 is a schematic diagram showing a method of fixing the optical connector 10 shown in FIG. 1 to the fixing jig 21 and the rotating direction of the polishing board 22. As shown in FIG. 4, in the case of the optical connector 10 shown in FIG. 1, a line connecting the center of the optical connector ferrule 1 and the center 31 of the polishing board and a line connecting the centers of the two fitting pin insertion holes 3. However, it is preferable that they intersect at a constant angle. The angle is preferably 60 ° or more and 120 ° or less. More preferably, the line connecting the center of the optical connector ferrule 1 and the center of the polishing board 22 and the line connecting the centers of the two fitting pin insertion holes 3 should be substantially orthogonal. In the case of being orthogonal, the optical fibers arranged in parallel between the two fitting pins can be located on substantially the same radius on the polishing board.
[0026]
The rotation direction 32 of the polishing disk is rotated toward the side of the optical connector ferrule 1 where the single mode type optical fiber 6 is provided, so that the abrasive grains first come into contact with the single mode type optical fiber 6 that is hard and difficult to cut. Since the multimode optical fiber 7 that is soft and easy to scrape comes into contact with the abrasive grains later , the difference in the protruding length of the single mode optical fiber 6 and the multimode optical fiber 7 from the optical connector ferrule 1 becomes small.
[0027]
When the optical connector fixed to the polishing jig 21 has the structure shown in FIG. 2 (i), a line connecting the center of the optical connector ferrule 1i and the center 31 of the polishing board and the two fitting pin insertion holes 3i. It is preferable that the line connecting the centers of the same direction. The polishing disk rotates toward the side where the single mode optical fiber 6 is disposed.
[0028]
As the abrasive grains, silica, alumina, cerium oxide and the like are suitable. The abrasive grains embedded in the polishing film 23 may be attached to the polishing board 22 or used, or a solution in which the abrasive grains are suspended may be hung on the polishing film.
[0029]
In particular, it is preferable to continuously drop the abrasive grains onto the polishing film 23 during polishing. By continuously dripping the abrasive grains, the abrasive grains that are not worn can come into contact with the optical fiber, so that polishing can always be performed under the same conditions.
[0030]
【Example】
An embodiment of the present invention will be described with reference to FIG. An optical connector ferrule 1 made of an epoxy resin containing silica powder at a high density and formed in a row of holes, four single mode type optical fibers 6 and two multimode type optical fibers 7 are arranged in a row in this order in an ultraviolet ray. The tape-shaped optical fiber 4 integrated with a coating made of a cured resin was inserted after removing the coating of the terminal portion, and fixed with an adhesive.
[0031]
A line connecting the center of the optical connector ferrule 1 and the center of the polishing board 22 and a line connecting the centers of the two fitting pin insertion holes 3 to the fixing jig 21 of the polishing apparatus shown in FIG. It fixed so that it might cross at 90 degrees, and the grinding | polishing of the end surface was implemented. A polishing film 23 made of a polyester cloth was pasted on the polishing board 22, and the end face of the ferrule 11 was pressed against the polishing film with a load of 6N. On the polishing film 23, polishing was performed while dropping a polishing liquid in which abrasive grains made of alumina having an average particle diameter of 1.0 μm to 3.0 μm were suspended in water.
[0032]
The rotation speed of the polishing board 22 is set to 135 rpm, and as shown in FIG. 4, the polishing board 22 is rotated toward the side where the single-mode optical fiber 6 is provided in the optical connector ferrule 1 to perform polishing for 240 seconds. The optical connector 10 shown in FIG. 1 was obtained.
[0033]
The 10-plug optical connector 10 was polished, its end face was measured with a surface roughness meter, and the unevenness of the end face of the optical fiber was measured. The protruding length of the optical fiber from the end face of the optical connector ferrule 1 was 2.4 μm on average. Further, among the six optical fibers, the difference between the largest protrusion and the smallest protrusion was 0.2 μm on an average of 10 plugs.
[0034]
The optical connector 10 is assembled in the housing 41 shown in FIG. 7, and the optical connectors 10 are coupled to each other through the adapter 42. When the connection loss at a wavelength of 1.3 μm is measured, the average of the single mode type optical fiber is 0.18 dB. The multimode type optical fiber showed a good value of 0.01 dB on average.
[0035]
When the optical fiber is protruded by 4.0 μm or more from the end face of the optical connector ferrule 1, the end of the optical fiber tends to be chipped when the attachment / detachment test between the optical connectors is repeated 500 times.
[0036]
As a comparative example, two multimode optical fibers 7 are arranged in the center on an optical connector ferrule 101 made of epoxy resin containing silica powder at a high density and having holes in a row, and two totals are provided on each side. A tape-shaped optical fiber core wire 104 in which four single-mode optical fibers 6 are arranged in parallel and integrated with a coating made of an ultraviolet curable resin is inserted after removing the coating at the tip, and fixed with an adhesive. The optical connector 110 shown in FIG.
[0037]
A line connecting the center of the optical connector ferrule 1 and the center of the polishing board 22 and a line connecting the centers of the two fitting pin insertion holes 3 to the fixing jig 21 of the polishing apparatus shown in FIG. Were fixed so that they intersect at 90 °, and polishing of the end face was performed. A polishing film 23 made of a polyester cloth was pasted on the polishing board 22, and the end face of the optical connector ferrule 101 was pressed against the polishing film with a load of 6N. On the polishing film 23, polishing was performed at 240 rpm for 240 seconds while dropping a polishing liquid in which abrasive grains made of alumina having an average particle diameter of 1.0 μm to 3.0 μm were suspended in water.
[0038]
The 10-plug optical connector 110 was polished, its end face was measured with a surface roughness meter, and the unevenness of the end face of the optical fiber was measured. The protruding length of the optical fiber from the end face of the optical connector ferrule 110 was 2.3 μm on average. The single-mode optical fiber 6 tends to have a longer protruding length than the multi-mode optical fiber, and the difference between the largest and smallest of the six optical fibers is the difference. The average of 10 plugs was 0.5 μm.
[0039]
The polished optical connector 110 is assembled in the housing 41 shown in FIG. 7, and the optical connectors 110 are coupled to each other via the adapter 42. The connection loss at a wavelength of 1.3 μm is measured. .21 dB, the multimode optical fiber averaged 0.12 dB, and the connection loss of the multimode optical fiber having a small protruding length tended to be large.
[0040]
When single mode type optical fiber and multimode type optical fiber are mixed and arranged in this way, multimode type optical fiber that is easy to be cut between two single mode type optical fibers that are hard to cut is The single mode optical fiber having a longer protruding length on both sides prevents contact with the optical fiber on the other side and does not cause PC coupling.
[0041]
As another comparative example, the optical connector 10 having the structure shown in FIG. 1 is fitted into the fixing jig 21 of the polishing apparatus shown in FIG. 3 with a line connecting the center of the optical connector ferrule 1 and the center of the polishing board 22 and two fittings. The line connecting the centers of the pin insertion holes 3 was fixed so as to intersect at 90 °, and the end face was polished. A polishing film 23 made of a polyester cloth was pasted on the polishing board 22, and the end face of the optical connector ferrule 1 was pressed against the polishing film 23 with a load of 6N. On the polishing film 23, polishing was performed while dropping a polishing liquid in which abrasive grains made of alumina having an average particle diameter of 1.0 μm to 3.0 μm were suspended in water. The polishing plate 22 was rotated at 135 rpm and the polishing plate 22 was rotated so that the multimode optical fiber 7 of the optical connector ferrule 1 was upstream, and polishing was performed for 240 seconds.
[0042]
The 10-plug optical connector 30 was polished, its end face was measured with a surface roughness meter, and the unevenness of the end face of the optical fiber was measured. The protruding length of the optical fiber 5 from the end face of the optical connector ferrule 1 was 2.3 μm on average. Further, the single-mode optical fiber 6 tends to have a longer protruding length than the multi-mode optical fiber, and the difference between the largest and smallest of the six optical fibers 5 is shown. The average of 10 plugs was 0.6 μm.
[0043]
【The invention's effect】
As described above, the optical connector manufacturing method of the present invention is an optical connector in which optical fibers having different hardnesses such as a single mode type optical fiber and a multimode type optical fiber are individually arranged together in an optical connector ferrule. in since the polishing plate is rigid optical fibers optical connector ferrule are arranged side by rotating the upstream to become oriented, it can be polished as variations in the protrusion length of the different optical fibers hardness decreases, total heart PC bond Can be realized.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an embodiment of an optical connector of the present invention.
FIG. 2 is a schematic diagram showing an example of an arrangement of optical fibers in the optical connector of the present invention.
FIG. 3 is a configuration diagram of a polishing apparatus used in the present invention.
FIG. 4 is a schematic view showing an embodiment of a method of fixing an optical connector on a polishing board and a rotating direction of the polishing board in the method of manufacturing an optical connector of the present invention.
FIG. 5 is a perspective view showing an optical connector of a comparative example of the present invention.
FIG. 6 is a perspective view showing a conventional optical connector.
FIG. 7 is a perspective view showing an example of an embodiment of an optical connector of the present invention.
[Explanation of symbols]
1, 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i
Optical connector ferrule 3, 3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h, 3i
Mating pin insertion hole 4 Tape-shaped optical fiber core wire 6 Single mode type optical fiber 7 Multimode type optical fiber 10 Optical connector 21 Ferrule fixing jig 22 Polishing plate 23 Polishing film 24 Case 31 Center of polishing plate 32 of polishing plate Rotation direction 41 Housing 42 Adapter 43 Fitting pin 101 Optical connector ferrule 103 Fitting pin insertion hole 104 Tape-shaped optical fiber core wire 201 Optical connector ferrule 203 Fitting pin insertion hole 204 Tape-shaped optical fiber core wire

Claims (3)

An optical connector ferrule has a plurality of optical fiber insertion holes, two fitting pin insertion holes on both sides thereof, and an optical connector in which an optical fiber is inserted and fixed in each of the plurality of optical fiber insertion holes. In the method of polishing and manufacturing using a disc, the plurality of optical fibers are composed of two types of optical fibers having different hardness, and the center of the optical connector ferrule on the contact surface of the optical connector ferrule with the polishing disc and the The optical connector ferrule is fixed on the polishing board so that a line connecting the centers of the polishing boards and a line connecting the centers of the two fitting pin insertion holes intersect at an angle of 60 ° to 120 °, A polishing disk rotates in a direction in which the side on which the hard optical fiber is arranged is upstream of the two types of optical fibers having different hardness in the optical connector ferrule. A method for manufacturing a connector. The optical fiber slightly protrudes from the end face of the optical connector ferrule, and the protrusion length is 1.5 μm or more and 4.0 μm or less, and the optical fiber with the longest protrusion and the optical fiber with the shortest protrusion are protruded. 2. The method of manufacturing an optical connector according to claim 1, wherein the polishing is performed until the difference in length becomes 0.3 [mu] m or less. The stiffness of two different optical fibers, the optical connector manufacturing method according to claim 1 or 2, characterized in that a single-mode optical fiber and a multimode optical fiber.

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