JP2000292649A - Ferrule for optical connector, and its end part machining method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an end part machining method for a ferrule for an optical connector enhanced in a polishing property and machining precision by reducing a PC polishing area of a tip face of a capillary part, and to provide the ferrule for the optical connector of high quality thereby at a low cost. SOLUTION: A connecting side end face of a capillary part 2 of a ferrule 1 for an optical connector formed with thin holes 3, 5 for attaching an optical fiber is ground into a spherical face (or plane) to form a convex spherical face part 7 (or plane part), then an outer circumferential part of the thin hole 3 is ground into a tapered shape remaining a prescribed area around the thin hole 3 to form a sloped part 8, and the part 7 (or the plane) is finish-polished thereafter in the condition that the optical fiber is attached in the holes 3, 5. The part 7 around the holes 3, 5 as a center is formed thereby in the connecting side end face of the capillary 2, and the tapered sloped part 8 is formed thereby in a periphery of the part 7, so as to provide the ferrule for the optical connector having 0.15-0.80 mm of diameter in the periphery of the hole 3 of the convex spherical face part 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ferrule for an optical connector used for connecting optical fibers to each other or an optical fiber and an optical circuit component, and a method of processing an end portion thereof, which is used in the optical communication field.

[0002]

2. Description of the Related Art FIG. 8 shows a state in which ferrules in a conventional single mode optical connector are joined to each other. The ferrule 1 includes a capillary portion 2 in which a small diameter hole 3 for inserting an optical fiber 10 (or an optical fiber) is formed along a central axis, and an optical fiber core 11 (optical fiber) along the central axis. The outer periphery of the fiber is covered with a jacket) The flange portion 4 is formed with a large-diameter fine hole 5 for insertion, and the small-diameter fine hole 3 and the large-diameter fine hole 5 are formed.
Are connected via a tapered diameter portion 6. Optical fiber 1
The tip of the optical fiber core 0 and the optical fiber core 11 are fixed in the pores 3 and 5 of the ferrule 1 by an adhesive.

[0003] A pair of optical fibers 10, 10 are connected by inserting the ferrules 1, 1 into which they are inserted and joined, from both ends of a sleeve 9, and abutting the ends of the ferrules 1, 1. Thus, the end faces are butt-connected while the axes of the optical fibers 10 and 10 are aligned. As the ferrule 1, there is an integral type in addition to the type in which the capillary portion 2 and the flange portion 4 are separate as shown in FIG. The tip of the capillary portion 2 is generally polished into a dome shape, that is, a convex spherical shape as shown in FIG. 8, in order to reduce the connection loss by setting the gap between the optical fibers to be abutted to zero. . Further, in order to reduce the reflection loss, it is also known that the tip end surface of the capillary portion of the inclined surface type ferrule in which the tip end surface of the capillary portion is inclined at a predetermined angle with respect to the axis of the optical fiber is spherically polished. (JP-A-7-124855
issue).

[0004]

There are two types of ferrules before machining a convex spherical surface: a flat type and a pre-dome type which is preliminarily ground into a convex spherical shape.
The area considerably larger than the contact surface (φ0.25 mm near the fiber) was polished. Therefore, there is a problem that polishing cost is increased. Further, when the flat surface is processed into a convex spherical surface, there is a problem in the processing accuracy after polishing due to a difference in shape (vertical deviation or the like), and it is necessary to perform re-polishing.
For this reason, a pre-dome type ferrule is used. However, since the finish polishing surface is wide as described above, there is a problem that a polishing time is long and a polishing cost is high.

Further, ferrules for optical connectors made of ceramics such as zirconia have a diameter of 2.5 mm or 1.5 mm.
mm, φ2.0 mm, etc. are used, but since the area for polishing the convex spherical surface is different, several types of polishing conditions are prepared. It is a factor of up.

On the other hand, Japanese Unexamined Patent Publication No. Hei 7-124855 describes a method of processing an inclined surface type ferrule. In this method, first, after tapering a tip portion, a slope having a predetermined inclination angle is formed at the tip. Then, the inclined surface is polished into a spherical shape. According to this method, although the area of polishing is reduced, the final polishing is performed from a flat surface to a spherical surface. Therefore, there is a problem that the polishing amount is large and it is difficult to match the top of the spherical surface with the center of the optical fiber.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its object to reduce the PC polishing area at the tip end surface of a capillary portion, thereby improving the polishing and processing accuracy for an optical connector. An object of the present invention is to provide a method of processing an end portion of a ferrule, thereby providing a high-quality optical connector ferrule at a low polishing cost. Further, the object of the present invention is to unify the polished surface so that it can be used for various ferrules, and therefore, it is possible to achieve uniform polishing conditions for various ferrules and achieve dual use or compatibility of a polishing machine. Another object of the present invention is to provide a method for processing an end portion of a ferrule for an optical connector, which can perform convex spherical polishing at low cost and with high processing accuracy.

[0008]

According to a first aspect of the present invention, there is provided a ferrule for an optical connector in which a fine hole for mounting an optical fiber is formed. In addition, a convex spherical portion or a flat portion having the pore as a center portion is formed, and a tapered inclined portion is formed around the convex spherical portion or the flat portion, and the convex spherical portion or the flat portion is formed. The diameter around the pores is 0.15 to 0.80 m
m, wherein a ferrule for an optical connector is provided.

According to a second aspect of the present invention, the connection side end face of the capillary portion of the ferrule for an optical connector, in which a fine hole for mounting an optical fiber is formed, is ground into a spherical shape or a planar shape, and a convex spherical portion or Forming a flat portion, then grinding the outer peripheral portion into a tapered shape leaving a predetermined area around the pore of the convex spherical portion or the flat portion to form an inclined portion, and then attaching an optical fiber to the pore. A method for processing an end portion of a ferrule for an optical connector, wherein the convex spherical portion or the flat portion is finish-polished in a state.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, according to the method for processing an end portion of a ferrule for an optical connector according to the present invention, a connecting spherical end surface of a capillary portion is ground into a spherical shape or a flat shape to form a convex spherical portion or a flat portion. Then, the outer peripheral portion of the convex spherical portion or the flat surface portion is ground in a tapered shape while leaving a predetermined area around the pore to form an inclined portion, and then the convex portion is formed with the optical fiber attached to the pore. This is for finishing and polishing the spherical portion or the flat portion. Therefore, the surface to be finish-polished is a convex spherical surface portion or a flat surface portion formed in advance by grinding, and has only a predetermined area around the pores other than the inclined portion formed by grinding in a tapered shape, that is, the pores. Perimeter 0.15-0.80
mm, the polishing amount is small, the polishing time is shortened, and the polishing cost can be reduced, and the processing accuracy is improved, and the optical fiber axis and the apex of the convex spherical portion or the flat portion are reduced. The center is hardly displaced. Furthermore, in the case of the convex spherical portion, the polishing surface can be unified by making the radius of curvature of the convex spherical portion constant by grinding, so that a single polishing machine can be used for final polishing of ferrules of various sizes. Benefits are obtained.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
The present invention will be described in more detail. FIG. 1 shows an embodiment of a ferrule for an optical connector according to the present invention. The ferrule 1 has a capillary portion 2 in which small-diameter pores 3 for inserting an optical fiber are formed along the central axis, and a large-diameter pore 5 for inserting an optical fiber core along the central axis. The small-diameter fine hole 3 and the large-diameter fine hole 5 are connected via a tapered diameter portion 6. On the tip end surface (connection end surface) of the capillary section 2,
As shown in an enlarged manner in FIG. 2, a convex spherical portion 7 centering on the pore 3 is formed, and a tapered inclined portion 8 is formed around the convex spherical portion 7. The convex spherical portion 7
Is set in the range of 0.15 to 0.80 mm. When the diameter D is less than 0.15 mm,
During the final polishing, the optical fiber cannot be sufficiently supported, and when the capillary portions 2 are abutted against each other, it is difficult to deform flat. On the other hand, if the diameter D exceeds 0.80 mm, the amount of finish polishing is large and the time is long, so that the finish polishing cannot be performed smoothly, and it is difficult for the fiber axis and the apex of the convex spherical portion to coincide with each other.

In the ferrule 1 shown in FIG. 1, the capillary portion 2 and the flange portion 4 are separately joined to each other by fitting and bonding or the like, but the capillary portion 2 and the flange portion 4 are joined together. It is needless to say that the processing method of the present invention can be applied to the tip end surface of the capillary portion of an integrally molded ferrule.

FIG. 3 shows a process for processing the end face of the capillary section 2 as described above. First, as shown in FIG. 3A, the tip surface of the capillary portion 2 after injection molding is such that the edge of the (a) flat surface or (a ′) flat surface is chamfered. As shown in FIG. 3 (B), spherical grinding is performed to form a convex spherical surface portion 7. Thereafter, the outer peripheral portion of the convex spherical portion 7 is ground to form a tapered inclined portion 8, and then the convex spherical portion 7 is mounted with the optical fiber 10 attached to the pore 3.
Finish polishing. The finish polishing is the same as the conventional one. For example, silicon oxide (SiO ₂ ), cerium oxide (Ce)
O ₂ ), using a polishing liquid containing a fine particle abrasive such as diamond.

In the spherical grinding for forming the convex spherical portion 7 as shown in FIG. 3 (B), for example, as shown in FIG. 4, a cup-shaped grinding tool 20 is rotated. Grinding can be performed efficiently by performing the pressing while pressing against the tip end surface of the capillary portion 2. FIG.
As shown in FIG. 5, for example, as shown in FIG. 5, an outer peripheral portion grinding process for forming the inclined portion 8 shown in FIG. 5C uses a grinding tool (grinder) 21 such as a diamond grindstone, and rotates the capillary portion. By performing the pressing while pressing against the convex spherical portion 7 at the tip end surface, the grinding can be efficiently performed.

FIG. 6 shows an example of a spherical finish polishing apparatus. The polishing device 22 includes a hollow rotary drum-shaped fixture 2.
3 and a polisher 24 made of a disc-shaped hard plastic film. The polisher 24 has its outer peripheral portion held down by a holding ring member 25 and is attached to the mounting member 23 in a stretched state. At the time of spherical finish polishing, the capillary part 2 on which the optical fiber 10 is mounted is held by a holder (not shown), and is rotated at a high speed while being reciprocated by a driving device (not shown) at a rotation angle of 180 degrees as shown by an arrow. This is performed by pressing the polisher 24 above the mounting fixture 23 with a predetermined polishing load. When the convex spherical portion 7 at the tip end surface of the capillary portion 2 is pressed against the polisher 24, the polisher 24 at the contact point portion is locally bent and deformed into an arc-shaped cross section. In this state, the capillary portion 2 is reciprocated while the polishing liquid is dropped on the upper surface of the polisher 24, so that the convex spherical portion of the tip end surface of the capillary portion 2 in contact with the polisher 24 is finish-polished.

FIG. 7 shows an example in which the present invention is applied to the machining of an inclined ferrule. In this case, first, FIG.
As shown in FIG. 7 (A), an inclined convex spherical surface portion 7a is formed on the distal end surface of the capillary portion 2 having an inclined surface formed at a predetermined inclination angle at the distal end as shown in FIG. 7 (B). . Thereafter, the outer peripheral portion of the convex spherical portion 7a is ground to form a tapered inclined portion 8a.
The above-mentioned convex spherical portion 7a is finished and polished in a state where is mounted.

In the above, the description has been made mainly of an example in which a convex spherical portion is formed around the pore at the connection end surface of the capillary portion of the ferrule for an optical connector, but the connection end surface of the capillary portion is ground into a flat shape, In the case where a flat portion having a predetermined area is formed around the hole, it can be similarly manufactured. In this case, for example, in the step shown in FIG. 3 or FIG. 7, the state shown in FIG. 3A or FIG.
As shown in FIG. 7C or FIG. 7C, the outer peripheral portion can be ground to form an inclined portion.

[0018]

As described above, according to the method for processing the end portion of the ferrule for an optical connector of the present invention, the surface on which the final polishing is performed is a convex spherical surface portion or a flat surface portion formed in advance by grinding. Moreover, since only a predetermined area around the pores other than the inclined portion formed by grinding in a tapered shape, that is, only a small area of 0.15-0.80 mm in diameter around the pores,
The polishing amount is small, the polishing time can be reduced, and the polishing cost can be reduced. Further, the center of the optical fiber axis and the apex of the convex spherical portion or the center of the flat portion hardly deviates. Therefore, a high-quality optical connector ferrule with high processing accuracy can be provided at low cost. Furthermore, in the case of a convex spherical portion, by making the radius of curvature of the convex spherical portion by grinding constant,
Since the polished surface can be unified, there is an advantage that a single polisher can be used for final polishing of ferrules of various sizes.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of an optical connector ferrule according to the present invention.

FIG. 2 is an enlarged cross-sectional view of a tip portion of a capillary section shown in FIG.

FIG. 3 is an explanatory view showing the steps of one embodiment of a method for processing an end portion of a ferrule for an optical connector according to the present invention.

FIG. 4 is a partial sectional view showing a spherical grinding step according to the present invention.

FIG. 5 is a partial sectional view showing an outer peripheral portion grinding step according to the present invention.

FIG. 6 is a partial sectional view showing a spherical finish polishing step according to the present invention.

FIG. 7 is an explanatory view showing the steps of another embodiment of the method for processing the end portion of the ferrule for an optical connector according to the present invention.

FIG. 8 is a partial cross-sectional view showing a connection state between ferrules for a conventional optical connector.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ferrule 2, 2a Capillary part 3, 5 Micropore 4 Flange part 6 Tapered diameter part 7, 7a Convex spherical part 8, 8a Inclined part 9 Sleeve 10 Optical fiber 20, 21 Grinding tool 22 Polishing device 23 Mounting tool 24 Polisher

Claims (2)

[Claims] 1. A convex spherical portion or a flat portion centering on the fine hole is formed on a connection side end face of a capillary portion of an optical connector ferrule in which a fine hole for mounting an optical fiber is formed, A tapered inclined portion is formed around the convex spherical portion or the flat portion, and the diameter of the convex spherical portion or the flat portion around the pores is 0.15 to 0.80 mm. Ferrule. 2. A spherical or planar grinding surface of a connection side end surface of a capillary portion of an optical connector ferrule in which a fine hole for mounting an optical fiber is formed to form a convex spherical portion or a planar portion, and then the convex portion is formed. Remaining a predetermined area around the pores of the spherical portion or the flat portion, the outer peripheral portion is ground in a tapered shape to form an inclined portion, and then the convex spherical portion or the flat portion in a state where an optical fiber is attached to the pores. A method of processing an end portion of a ferrule for an optical connector, characterized by finishing polishing.