JP2001091793A - Optical fiber fixture, its assembling method and optical fiber connector using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce manufacturing cost by lessening an average value and variance of a connection loss being an optical characteristic as an optical fiber connector and moreover saving inside diameter working, inside diameter selecting working, concentricity working and concentricity selecting working. SOLUTION: In an optical fiber fixture for a single mode wherein the difference between the outside diameter 11a of an optical fiber and the inside diameter of a ferrule axial hole 1a exceeds 1.0 μm, the concentricity of the optical fiber center 11b to the outer periphery 1c of the ferrule is fixed within range of 1.4 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber connector and an optical fiber fixing device for connecting optical fibers used for optical communication and the like to each other.

[0002]

2. Description of the Related Art Conventionally, a pair of optical fiber fixtures holding an optical fiber is used in places where detachable optical connection such as switching of equipment, removal of transmission / reception ports, adjustment of equipment, measurement, etc. is required. 2. Description of the Related Art An optical fiber connector is used in which optical fibers are optically connected to each other by bringing the tips into contact with each other and holding them.

For example, an optical fiber connector 1 shown in FIG.
Numeral 0 indicates that a pair of optical fiber fixtures 3 are in contact with each other. The optical fiber fixture 3 has a ceramic ferrule 1 having a shaft hole 1a through which an optical fiber 11 is inserted and fixed, a concave portion 2a into which the ferrule 1 is fitted, and communicates with the concave portion 2a to form an axis of the ferrule 1. Hole 1a
And a ferrule support 2 made of metal or resin having a through-hole 2 b coaxial with the ferrule 1.
The optical fiber 11 is inserted into the ferrule support 2 and the adhesive 13 is filled in the through hole 2b of the ferrule support 2.
Is fixed. And the optical fiber connector 10
An adapter having a pair of optical fiber fixing members 3 and a sleeve 14 for connecting and holding the tips of the ferrules 1 of the optical fiber fixing members 3 in contact with each other, and having an outer periphery of the sleeve 14 having threaded portions at both ends. A coupling 15 is provided, and a coupling nut 16 is screwed to both ends of the adapter coupling 15, and the optical fiber is pressed by a pressing force of a spring 17 disposed between each coupling nut 16 and the ferrule support 2. The ends of the ferrules 1 of the fixture 3 are brought into contact with each other to optically connect the optical fibers 11 to each other.

As shown in FIG. 8, the conventional single-mode optical fiber fixing device 3 has a difference between the diameter of the shaft hole 1a of the ferrule 1 and the optical fiber outer diameter 11a within 1 μm, and Since the center of the hole 1a is set within a concentricity of 1.4 μm with respect to the diameter of the outer circumference 1c,
If the optical fiber 11 is inserted into the shaft hole 1a of the ferrule 1 and fixed, the center 11b of the optical fiber 11 is designed to be substantially centered with respect to the outer periphery 1c of the ferrule 1.

[0005]

However, in the conventional optical fiber fixture 3, it is necessary to perform inner diameter processing and concentricity processing in order to form the shaft hole 1a of the ferrule 1 with high precision. Because of the small size, they are processed by grinding or polishing. However, they have no process capability, and all the inner diameter sorting work and all the concentricity sorting work have been performed.

[0006] For this reason, the optical fiber connector 10 of the last minute is included, and there is a problem that the variation of the connection loss, which is the optical characteristic of the optical fiber connector 10, becomes large.

Further, there is a serious problem that since the inner diameter machining, the inner diameter sorting work, the concentricity machining, and the concentricity sorting machining of the shaft hole 1a require a large production cost, it is impossible to meet the market demand price. there were.

[0008]

SUMMARY OF THE INVENTION In view of the above problems, the present invention comprises a ferrule having a shaft hole and a ferrule support having a through hole coaxial with the shaft hole of the ferrule. In an optical fiber fixture in which an optical fiber is inserted and fixed with an adhesive, the difference between the outer diameter of the optical fiber and the inner diameter of the shaft hole of the ferrule is larger than 1.0 μm, and the center of the optical fiber with respect to the outer periphery of the ferrule is adjusted. The concentricity is set to 1.4 μm or less.

Further, the present invention has a ferrule having a shaft hole, and a ferrule support having a through hole coaxial with the shaft hole of the ferrule, wherein an optical fiber is inserted into the shaft hole of the ferrule and an adhesive is used. In the method for assembling a fixed optical fiber fixture, the center of the optical fiber is 1.4 μ concentric with the outer periphery of the ferrule with respect to the outer periphery of the ferrule.
m, and the optical fiber is fixed with an adhesive.

Further, in the present invention, in the above-mentioned assembling method, at least an optical fiber mounting portion of the ferrule is formed of a transparent material, a shaft hole of the ferrule is filled with a conditional instant adhesive, and an optical fiber is inserted. After the alignment between the outer periphery and the center of the optical fiber is performed, the adhesive is cured.

Further, according to the present invention, in the above assembling method, an adhesive is filled into a shaft hole of a ferrule, and an optical fiber is inserted.
After aligning the outer circumference of the ferrule with the large-diameter part of the assembly jig having the large-diameter part and the small-diameter part, and fitting the optical fiber to the small-diameter part, it is necessary to cure the adhesive after positioning. Features.

Further, the present invention provides the above optical fiber fixture,
The optical fiber connector is formed by connecting the optical fibers by bringing the tips of the other optical fiber fixing members into contact with each other.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1A is a longitudinal sectional view of an optical fiber fixture 3 showing a first embodiment of the present invention, and FIG. 1B shows a state in which a ferrule 1 of the present invention and an optical fiber 11 are fixed. It is sectional drawing.

An optical fiber fixing device 3 according to the present invention is made of a ceramic ferrule 1 having a shaft hole 1a for inserting and fixing an optical fiber 11, and a metal ferrule 1 having a through hole 2b coaxial with the shaft hole 1a of the ferrule 1. Alternatively, the ferrule support 2 is made of resin, and the shaft hole 1a of the ferrule 1 is formed.
The optical fiber 11 is inserted into the ferrule support 2
The optical fiber 11 is fixed by filling the through hole 2b with an adhesive 13.

The optical fiber fixture 3 makes the difference between the inner diameter of the shaft hole 1a of the ferrule 1 and the outer diameter 11a of the optical fiber 11 larger than 1 μm, and
1b is a concentricity of 1.4 μ with respect to the outer circumference 1c of the ferrule 1.
m.

By making the difference between the inner diameter of the shaft hole 1a of the ferrule 1 and the outer diameter 11a of the optical fiber 11 larger than 1 μm, there is no need to precisely polish the shaft hole 1a when the ferrule 1 is manufactured. In this case, the fired surface itself can be sufficiently used as the ferrule 1, and the processing cost of the ferrule 1 can be greatly reduced.

Even if the difference between the inner diameter of the shaft hole 1a of the ferrule 1 and the outer diameter 11a of the optical fiber 11 is larger than 1 μm, the center 11
b is 1.4 μm concentricity with the outer circumference 1 c of the ferrule 1
The shaft hole 1 with respect to the outer circumference 1c can be
The concentricity of “a” does not need to be precise, and it is not necessary to perform the processing for setting the concentricity of the shaft hole 1a within the standard.

Here, the reason why the center 11b of the optical fiber 11 needs to have a concentricity of 1.4 μm or less with respect to the outer circumference 1c of the ferrule 1 is that if the concentricity exceeds 1.4 μm, the optical fiber connector will When the optical fibers are connected by bringing the ends of the optical fiber fixtures 3 into contact with each other, the deviation of the center position of the optical fibers is too large,
This is because the connection loss, which is an important characteristic of the optical fiber connector, is deteriorated. For this reason, the concentricity is defined as 1.4 μm as the ferrule dimension of the F04 type single core optical fiber connector (commonly referred to as SC connector) in the JIS standard.

In the optical fiber fixture 3 of the present invention, the material of the ferrule 1 is ceramics such as alumina and zirconia, glass such as borosilicate glass and crystallized glass, and PE.
Plastics such as S, PEI, and LCP can be used.

The ferrule support 2 is made of PBT, LC
Plastics such as P, stainless steel, nickel plating on brass, and metal such as nickel plating on brass can be used.

The ferrule 1 has a structure in which a cone 1b is formed at the inlet of the optical fiber 11, but may have an R surface or may be omitted.

FIG. 2 is a longitudinal sectional view of an optical fiber fixing device 3 according to a second embodiment of the present invention.

The optical fiber fixture 3 has a ferrule 1 made of ceramics or glass for fixing the optical fiber 11 fixed at its tip. The outer circumference 2c of the ferrule support 2 made of metal or plastic is shown in FIG. And serves as the outer periphery 1c of the ferrule 1 of the first embodiment, and is a portion to be gripped by the sleeve 14 of the optical fiber connector.

Next, FIG. 3 is a longitudinal sectional view of an optical fiber fixture 3 showing a third embodiment of the present invention.

The optical fiber fixture 3 is made of metal or plastic and has an integral structure, and does not have the ferrule 1. However, the optical fiber fixture 3 has a shaft hole 1a for fixing the optical fiber 11, an outer diameter 1c, and has a function. This is exactly the same as the first embodiment and the second embodiment of the present invention. In this embodiment, a ferrule 1 and a ferrule support 2 are integrally formed.

Next, a method for assembling the optical fiber fixture of the present invention will be described. FIG. 4 is a longitudinal sectional view showing a method of assembling the optical fiber fixture 3 according to the first embodiment of the present invention.

The ferrule 1 of the optical fiber fixture 3 is formed of a transparent material such as borosilicate glass, translucent ceramics, or transparent plastic, and the shaft hole 1a of the ferrule 1 is filled with an ultraviolet curable adhesive 13. Thereafter, the optical fiber 11 is inserted, and the outer circumference 1c of the ferrule 1 and the optical fiber 1 are inserted.
The optical fiber 11 is rotated while observing an image of the center 11b projected by the camera 21 on the monitor 22, and the concentricity between the optical fiber center 11b and the outer circumference 1c of the ferrule is aligned within 1.4 μm. Then, the adhesive 13 is cured by irradiating ultraviolet rays.

The observation method is as follows: the camera 21 and the monitor 22
A method of directly viewing with a microscope without using a microscope is also acceptable. Also, camera 2
The same effect can be obtained by processing the image captured in step 1 and moving the optical fiber to the optimum position by automatic control.

The adhesive 13 may be a conditional instant adhesive that can be instantaneously adhered and solidified under given conditions. For example, as described above, a method of fixing the optical fiber 11 by irradiating ultraviolet rays and then fixing the optical fiber 11 instantaneously after performing alignment using an ultraviolet curing adhesive, or after performing alignment in a chamber using an anaerobic adhesive. The same effect can be obtained by a method of instantly fixing the optical fiber 11 by applying a vacuum.

FIG. 5 is a longitudinal sectional view showing a method of assembling the optical fiber fixture according to the second embodiment of the present invention.

After filling the shaft hole 1a of the ferrule 1 of the optical fiber fixture 3 with an adhesive 13 such as an epoxy resin, the optical fiber 11 is inserted into the shaft hole 1a, and an assembly jig having a large inner diameter portion 31 and a small inner diameter portion 32 is provided. After the outer circumference 1c of the ferrule 1 is fitted to the large inner diameter portion 31 of the ferrule 1 and the distal end portion 11c of the optical fiber 11 is fitted to the small inner diameter portion 32, and the positioning is performed, the adhesive 13 is cured.

Here, the adhesive 13 is not limited to the epoxy adhesive, but may be an ultraviolet curable adhesive. The ferrule 1 may be made of ceramic such as zirconia or alumina, glass such as borosilicate glass, crystallized glass, or LCP. , PES,
Plastic such as PEI can be used.

The material of the assembling jig 30 may be metal or ceramics.
It is preferable to use zirconia and zirconia of the same material for the assembly jig 30. This is because zirconia has a smaller coefficient of linear expansion than metal, and the ferrule 1 and the assembling jig 30 have the same coefficient of linear expansion. In addition, a precise assembly jig can be manufactured by polishing using the processing technique of the ferrule 1.

As described above, the method of assembling the optical fiber fixture 3 is based on the outer circumference 1c of the ferrule 1 and the optical fiber 1
The center 11 b of the ferrule 1 is aligned with the outer circumference 1 c of the ferrule 1 within a range of concentricity of 1.4 μm, and the optical fiber 11 is fixed to the optical fiber fixture 3 with the adhesive 13.

That is, the optical fiber fixture 3 of the present invention does not need to perform the inner diameter machining and the concentricity machining of the shaft hole 1a of the ferrule 1, and therefore does not need the inner diameter sorting operation and the concentricity sorting operation.

Further, since it is possible to assemble with an optical fiber which is stable and has no variation, it does not include a barely standard optical fiber, and it is possible to suppress a connection loss which is an important optical characteristic as an optical fiber connector. Was.

Further, since the inner diameter machining, the inner diameter sorting work, the concentricity machining, and the concentricity sorting machining are eliminated, and the steps that occupy most of the production are omitted, the production cost can be greatly reduced.

Finally, as shown in FIG. 7, the optical fiber connector 10 has a pair of optical fiber fixtures 3 and a sleeve 14 for connecting and holding the ends of the ferrules 1 of the optical fiber fixtures 3 in contact with each other. The outer periphery of the sleeve 14 is provided with an adapter coupling 15 having screw portions at both ends, and the adapter coupling 15 is provided.
The coupling nuts 16 are screwed into the threaded portions of the optical fiber fixing device 3 and the ends of the ferrules 1 of the optical fiber fixture 3 are brought into contact with each other by the pressing force of a spring 17 disposed between each coupling nut 16 and the ferrule support 2. The optical fibers 11 are optically connected to each other.

Moreover, even if the optical fiber connectors of the present invention are not in contact with each other, the ends of the optical fiber fixture 3 of the present invention and another optical fiber fixture are brought into contact with each other to connect the optical fibers. An optical fiber connector configured as described above may be used.

[0041]

EXAMPLE Here, an experiment was conducted by the following method.

The outer diameter D of the single mode ferrule made of zirconia ceramics D = φ2.5 mm, and the length L = 10.
8 mm as a comparative example with a shaft hole d = φ0.126 mm
The conventional optical fiber fixing device shown in FIG. 1 and the optical fiber fixing device shown in FIG. 1 as the first embodiment of the present invention are each made up to 100 samples, and a spring, a coupling nut and the like are assembled into an optical fiber connector, and connected. The loss was measured. FIG. 6 shows the result.

The optical fiber connector of the present invention has a small average connection loss and small variations. On the other hand, the conventional optical fiber connector as a comparative example has a result that the average value of the connection loss is large and the variation is large.

[0044]

As described above, according to the present invention, a ferrule having a shaft hole and a ferrule support having a through hole coaxial with the shaft hole of the ferrule are provided. In an optical fiber fixture in which a fiber is inserted and fixed with an adhesive, the difference between the outer diameter of the optical fiber and the inner diameter of the ferrule is larger than 1.0 μm, and the center of the optical fiber with respect to the outer diameter of the ferrule is 1. By setting the thickness within the range of 4 μm, the average value and the variation of the connection loss, which are the optical characteristics of the optical fiber connector, are reduced, and the inner diameter machining of the shaft hole, the inner diameter sorting work, the concentricity machining, and the concentricity sorting work are omitted. Therefore, the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1A is a longitudinal sectional view of an optical fiber fixture according to a first embodiment of the present invention, and FIG. 1B is a sectional view showing a state in which the ferrule of the present invention and an optical fiber are fixed. .

FIG. 2 is a longitudinal sectional view of an optical fiber fixture according to a second embodiment of the present invention.

FIG. 3 is a longitudinal sectional view of an optical fiber fixture showing a third embodiment of the present invention.

FIG. 4 is a longitudinal sectional view showing a method of assembling the optical fiber fixture according to the first embodiment of the present invention.

FIG. 5 is a longitudinal sectional view showing a method for assembling an optical fiber fixture according to a second embodiment of the present invention.

FIG. 6 is a graph comparing a connection loss between the first embodiment of the present invention and a conventional example.

FIG. 7 is a longitudinal sectional view showing an optical fiber connector.

FIG. 8A is a longitudinal sectional view of a conventional optical fiber fixture, and FIG. 8B is a sectional view showing a state in which a conventional ferrule and an optical fiber are fixed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ferrule 1a Shaft hole 1b Cone 1c Outer circumference 2 Ferrule support 2a Depression 2b Through-hole 2c Outer circumference 3 Fiber fixing device 10 Optical fiber connector 11 Optical fiber 11a Optical fiber outer diameter 11b Optical fiber center 11c Tip 13 Adhesive 14 Sleeve 15 Adapter Coupling 16 Coupling nut 17 Spring 21 Camera 22 Monitor 30 Assembly jig 31 Large bore 32 Small bore

Claims (5)

[Claims] 1. A ferrule having a shaft hole and a ferrule support having a through hole coaxial with the shaft hole of the ferrule, wherein an optical fiber is inserted into the shaft hole of the ferrule and fixed with an adhesive. In the optical fiber fixing device, the difference between the outer diameter of the optical fiber and the inner diameter of the shaft hole of the ferrule is larger than 1.0 μm, and the concentricity of the center of the optical fiber with respect to the outer periphery of the ferrule is 1.4 μm or less. Fiber optic fixture. 2. A ferrule having a shaft hole, and a ferrule support having a through hole coaxial with the shaft hole of the ferrule, wherein an optical fiber is inserted into the shaft hole of the ferrule and fixed with an adhesive. In the method of assembling the optical fiber fixture, the center of the optical fiber is aligned with the outer periphery of the ferrule so as to have a concentricity of 1.4 μm or less based on the outer periphery of the ferrule, and the optical fiber is fixed with an adhesive. A method for assembling an optical fiber fixture, comprising: 3. The ferrule has at least an optical fiber mounting portion formed of a transparent material, a shaft hole of the ferrule is filled with a conditional flash adhesive, an optical fiber is inserted, and the outer periphery of the ferrule is aligned with the center of the optical fiber. 3. The method for assembling an optical fiber fixture according to claim 2, wherein the adhesive is cured after performing the step (a). 4. An optical fiber is inserted into the shaft hole of the ferrule with an adhesive, and the outer periphery of the ferrule is fitted to the large inner diameter portion of an assembling jig having a large inner diameter portion and a small inner diameter portion. 3. The method for assembling an optical fiber fixing device according to claim 2, wherein the adhesive is cured after the positioning is performed by fitting the optical fiber to the optical fiber. 5. An optical fiber connector wherein the optical fibers are connected by bringing the ends of the optical fiber fixing device of claim 1 into contact with the other optical fiber fixing devices.