JP2003307648A - Optical fiber fixture, its assembling method, and optical fiber pigtail using this fixture - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce connection loss due to the formation of air staying portions with an adhesive, when using an optical fiber pigtail, in the occurrence of chipping, cracking and deformation of a ferrule. <P>SOLUTION: The optical fiber fixture 3 is composed of a ferrule 1 having a fine hole 1a for inserting an optical fiber and a ferrule supporting body 2 having a recess 2a for fitting the outer circumference of the rear end of the ferrule 1 and having a through hole 2b for inserting the optical fiber. In the recess 2a of the ferrule supporting body 2, at least two non-contact areas 2d are provided with respect to the outer circumference of the ferrule 1. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber fixture used for optical communication, a method of assembling the same, and an optical fiber pigtail in which an optical fiber is held in the optical fiber fixture.

[0002]

2. Description of the Related Art Conventionally, a pair of optical fiber pigtails holding an optical fiber is used at a place where a detachable optical connection such as switching of a device, removal of a transmission / reception port, adjustment of a device, and measurement is required in an optical communication system. 2. Description of the Related Art An optical connector is used in which optical fibers are optically connected to each other by abutting and holding the end faces so as to be connected and held.

For example, the optical connector shown in FIG. 5 has a ceramic ferrule 11 having pores 11a through which an optical fiber 17 is inserted and fixed, a recess 12a into which the ferrule 11 is fitted, and a communication with the recess 12a. Of the ferrule 11 and the pore 11a of the ferrule 11 of the optical fiber fixture 13 including the ferrule support 12 made of metal or resin having the through hole 12b coaxial with the pore 11a of the ferrule 11.
And a pair of optical fiber pigtails 1 in which the optical fiber 17 is inserted and held in the through hole 12b of the ferrule support 12.
9 and a sleeve 20 for connecting and holding the front end surfaces of the optical fiber pigtail 19 in contact with each other, and an adapter coupling 21 having screw portions at both ends is arranged on the outer periphery of the sleeve 20. Coupling nuts 22 are screwed into both ends of the adapter coupling 21, and the optical fiber pigtail 19 is pressed by the pressing force of a spring 23 arranged between each coupling nut 22 and the ferrule support 12.
The optical fibers 17
They are designed to optically connect each other.

In order to bring the optical fibers 17 into contact with each other with certainty, the length of the ferrule 11 protruding from the ferrule support 12 (hereinafter referred to as step length) is important. Since the ferrules 11 cannot be brought into contact with each other inside, optical connection becomes impossible,
On the contrary, if the step length is too long, there is a problem that the distance between the adapter coupling 21 and the coupling nut 22 becomes insufficient, and the optical connector cannot be constructed.

Therefore, the optical fiber pigtail 19 described above is used.
As an optical fiber fixture 13 used in FIG.
In FIG. 6 (b), there is used a bottomed optical fiber fixture 13 in which the end face of the ferrule 11 is press-fitted into the bottom surface of the recess 12a of the ferrule support 12 to bring the outer periphery of the ferrule into contact. An optical fiber fixture 13 of the bottom floating specification has been used in which the end face of the ferrule 11 as shown is fitted with the bottom surface of the recess 12a of the ferrule support 12 with a gap (see Japanese Patent Laid-Open No. 9-43451).

[0006]

However, as shown in FIG.
In the optical fiber fixture 13 as shown in (a), it is necessary to strictly control the dimensional accuracy of the inner diameter and the depth of the recess 12a of the ferrule 11 and the ferrule support 12 in order to control the step length, and therefore, strict control is required. There was a problem that work was required, work efficiency was poor, and the cost was high. Further, since the outer periphery and the end surface of the ferrule 11 come into contact with the recess 12a of the ferrule support 12 during press fitting, if the press fitting load is excessive, the ferrule 11 is likely to be chipped,
The ferrule support 12 may be bent.

The optical fiber fixture 13 as shown in FIG. 6B has a bottom surface of the ferrule 11 and the ferrule support 1.
The bottom surface of the second recess 12a is not in contact, and the size of the gap is generally about 0.1 mm, which means that the press-fitting can be easily performed without strictly controlling the dimensional accuracy of the depth of the recess 12a. Although there is an advantage, it is not possible to supply a sufficient amount of the adhesive filled in the through hole 12b of the ferrule support 12 between the ferrule 11 and the bottom surface of the recess 12a of the ferrule support 12, so that an air pocket is formed. Since it is formed, it has a defect that the optical fiber is easily broken or damaged during the heat cycle.

That is, if there is an air pocket between the ferrule 11 and the recess 12a of the ferrule support 12, the air in the air pocket gives a large expansion pressure to the optical fiber 17 when a thermal cycle shock is applied to the optical connector. By repeating this stress over a long period of use, the optical fiber 17 may be damaged, or the stress may be concentrated on a specific portion of the optical fiber 17 due to the nature of air pockets, causing damage to the optical fiber 17. I was afraid to end up.

In both the bottomed specification optical fiber fixing tool 13 as shown in FIG. 6A and the bottom floating specification optical fiber fixing tool 13 as shown in FIG. 6B, the ferrule is provided in the recess 12 a of the ferrule support 12. Since 11 is press-fitted and fixed, when the ceramic ferrule 11 is used, cracks and cracks are likely to occur at the time of press-fitting, the ferrule support 12 is deformed, and the press-fit is insufficient if the dimensional accuracy is poor. Then, there is a drawback that the ferrule 11 comes off when a stress is applied.

[0010]

In view of the above, the optical fiber fixture of the present invention has a ferrule having pores for inserting an optical fiber, a recess for fitting the outer periphery of the rear end of the ferrule, and an optical member. An optical fiber fixture comprising a ferrule support having a through hole for inserting a fiber, characterized in that at least two non-contact parts are provided in the recess of the ferrule support with respect to the outer circumference of the ferrule. is there.

The optical fiber fixture of the present invention is characterized in that an adhesive agent reservoir is provided in the recess of the ferrule support.

Further, the optical fiber fixture of the present invention is characterized in that at least two notches are provided on the outer peripheral surface of the recess of the ferrule support.

Furthermore, in the method of processing an optical fiber fixture of the present invention, the rear end of the ferrule is inserted into the recess of the ferrule support, and the notch of the ferrule support is caulked to fix the outer periphery of the ferrule. It is characterized by doing.

Furthermore, an optical fiber pigtail using the optical fiber fixture of the present invention is characterized in that the optical fiber is inserted and held in the pores of the ferrule and the through holes of the ferrule support. is there.

According to the optical fiber fixture of the present invention, at least the concave portion of the ferrule support of the optical fiber fixture comprising the ferrule and the ferrule support body having the concave portion for fitting the outer periphery of the rear end of the ferrule. Since the two non-contact parts are provided, the optical fiber and the ferrule support can be firmly adhered, and air bubbles of the adhesive do not occur. Therefore, the optical fiber is prevented from being damaged and highly reliable. A fiber pigtail can be obtained.

Further, according to the optical fiber fixture of the present invention, since at least two notches are provided on the outer peripheral surface of the recess of the ferrule support, the ferrule and the ferrule support are stably caulked and fixed. be able to.

Further, according to the optical fiber fixture of the present invention, since the adhesive reservoir is provided in the concave portion of the ferrule support, the adhesive does not jump out from the end face of the support and the insertability into the sleeve is improved. It does not hurt.

Furthermore, according to the optical fiber fixture processing method of the present invention, the rear end of the ferrule is inserted into the recess of the ferrule support, and the notch of the ferrule support is caulked to the outer periphery of the ferrule. Since it is fixed, it is not necessary to process the ferrule support with high accuracy, and it is possible to effectively prevent chipping of the ferrule, occurrence of cracks, and deformation of the ferrule support.

Furthermore, according to the optical fiber pigtail using the optical fiber fixture of the present invention, it is not necessary to process the ferrule support with high accuracy, and the ferrule is chipped, cracked or deformed. Moreover, the problem of press-fitting does not occur, and further, the adhesive for fixing the optical fiber does not cause air pockets, and a highly reliable optical fiber pigtail can be obtained.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1A is a front view showing an embodiment of the optical fiber fixture of the present invention, and FIG. 1B is a sectional view taken along line XX.

The optical fiber fixture 3 of the present invention comprises a ferrule 1 having pores 1a for inserting an optical fiber,
The ferrule 1 comprises a ferrule support 2 having a recess 2a for fitting the outer periphery of the rear end of the ferrule 1 and a through hole 2b for inserting an optical fiber.

The ferrule 1 is made of ceramics such as alumina and zirconia, glass such as borosilicate glass and crystallized glass, plastics such as PES, PEI and LCP, and metals such as stainless steel and nickel alloys. It is preferable to have a pore 1a through which an optical fiber is inserted and to be formed of ceramics containing zirconia as a main component.

Specifically, ZrO ₂ is the main component, and Y ₂ O ₃ , MgO, CaO, CeO ₂ , and Dy ₂ O are used as stabilizers.
This is because it contains one or more such as _{3 and the} like, and it is possible to obtain stability mainly based on tetragonal crystals.

Further, it is preferable that the pore 1a of the ferrule 1 has a taper portion 1b at the end portion on the side fixed to the ferrule support 2 to enhance the insertability of the optical fiber.

The rear end of the ferrule 1 is fixed in the recess 2a of the ferrule support 2, and the ferrule support 2 is made of stainless steel, brass-nickel-plated metal, or the like. Has a through hole 2c for inserting an optical fiber in the axial direction that communicates with the small hole 1a, and in particular, stainless steel is easy to process, does not rust even if deformed by caulking, and has a low manufacturing cost. Is preferred.

Here, the recess 2 of the ferrule support 2 is used.
It is important that a is provided with at least two non-contact portions 2d between it and the outer periphery of the fixed ferrule 1.

This is the through hole 2b of the ferrule support 2.
When the optical fiber is inserted into the optical fiber to form an optical fiber pigtail, the adhesive flows into the non-contact portion 2d when the adhesive holding the optical fiber is filled, so that the ferrule 1
And, the fixing strength of the ferrule support 2 can be made stronger. Further, unlike the conventional case, since the taper portion 1b of the ferrule 1 is not sufficiently filled with the adhesive, the bubbles move to the corners of the recess to form an air pocket, but the non-contact portion 2
Due to d, excess air is generated through the through hole 2 of the ferrule support 2.
The adhesive that has entered from the b side advances toward the non-contact portion 2d and does not leave air bubbles in the taper portion 1b by pushing out air to form an air pocket, and the optical fiber can be used even under severe heat cycle conditions. It is possible to effectively prevent damage to the.

The recess 2a of the ferrule support 2 is also provided.
It is preferable to form a notch 2c on the outer periphery of
It serves as an anti-rotation function when used as an optical connector, and when assembling the ferrule 1 and the ferrule support 2, the inner diameter of the recess 2a of the ferrule support 1 is set from the outer diameter of the ferrule 1 when the ferrule 1 and the ferrule support 2 are assembled. The ferrule 1 is fixed to the ferrule support 2 by caulking the notch 2c of the ferrule support 2 after inserting the ferrule 11 into the recess 2a while increasing the size by 3 μm to 1 mm. Therefore, as shown in FIG.
A concave crushed mark remains in the portion corresponding to the cutout portion 2c, and only the portion of the recessed portion 2a corresponding to the cutout portion 2c comes into contact with the outer periphery of the ferrule 1, and the non-contact portion 2d.
Is formed.

Further, the non-contact portion 2d formed on the ferrule support 2 may be at least two places, preferably four places. this is,
The optical fiber fixture 3 used for the most standard SC type optical connector in the optical connector has four cutouts 2c formed for preventing rotation, and the caulking process of the present invention is easy to perform, and the fixing strength is high. Can be more stable.

The notch 2c formed on the ferrule support 2 is fixed to the recess 2a.
It suffices that the caulking can be performed, and the caulking may be performed by forming a flat surface portion in addition to the cutout portion 2c.

Further, as shown in FIGS. 2 (a) and 2 (b), the adhesive reservoir 2e is formed in the recess 2a of the ferrule support 2.
Is preferably provided. By providing the adhesive reservoir 2e, the adhesive for holding the optical fiber adheres to the outer periphery of the ferrule 1 and the like, and the outer diameter of the ferrule 1 increases, so that the optical connector can be smoothly inserted into the split sleeve when forming the optical connector. Can be done.

The adhesive reservoir 2e is shown in FIG.
A plurality of grooves may be provided as shown in (c).

Next, a method of assembling the optical fiber fixture 3 of the present invention will be described.

FIG. 3 is a sectional view showing an assembling method of the optical fiber fixture 3 of the present invention. The ferrule 1 having the pores 1a is inserted into the hole of the lower jig 6 from the front end side. The depth of the hole of the lower jig 6 is adjusted to the amount of protrusion of the ferrule 1 from the end surface of the ferrule support 2 standardized in the optical connector.

Next, the recess 2a of the ferrule support 2 is placed on the lower side, and the ferrule 1 is set on the upper surface of the lower jig 6 so that the outer peripheral portion 1b of the ferrule 1 enters the recess 2a.

Caulking sleeve 5 having four claws 5a
The caulking jig made up of the taper ring 4 reduces the inner circumference of the claw 5a, compresses the notch 2c, and deforms the recess 2a to fix the outer circumference of the ferrule 1.

Here, when a load is applied to the upper part of the taper ring 4 of the caulking jig, the taper of the inner circumference of the taper ring 4 is lowered and the taper outer circumference of the caulking sleeve 5 having four slits at the tip is removed. To reduce. Along with that, the inner circumference of the claw 5a becomes smaller and the notch 2c is compressed,
The recess 2a is deformed to fix the outer circumference of the ferrule 1.

At this time, when the load is applied to the upper part of the taper ring 4, it is preferable to apply the load instantaneously. This is because if the load is applied gradually, a sufficient caulking effect cannot be obtained.

Here, the taper ring 4, the caulking sleeve 5, and the lower jig 6 can be made of metal or ceramics. However, when zirconia is used for the ferrule 1, the same material, zirconia, is preferably used. Since the linear expansion coefficient is small and the same linear expansion coefficient does not affect the temperature, it is preferable.

In the optical fiber fixture 3 obtained as described above, the through hole 2b of the ferrule support 2 is filled with the adhesive 8 as shown in FIG.
And, the optical fiber 7 is inserted into the through hole 2b of the ferrule support 2, and the optical fiber 7 and the ferrule 1 and the ferrule support 2 are simultaneously fixed by the same adhesive 8,
The optical fiber pigtail 9 can be obtained by finishing polishing the front end surface of the ferrule 1 together with the front end surface of the optical fiber 7.

The adhesive 8 may be an anaerobic adhesive or a photo-curing adhesive. When the photo-curing adhesive is used, the ferrule 1 is a transparent member such as borosilicate glass or crystallized glass. It is preferable to use the above glass.

The optical fiber fixture 3 of the present invention can be used for a single mode optical fiber and a multimode optical fiber. Further, the optical fiber is not limited to the quartz type, and the same effect can be obtained with a plastic type.

[0044]

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

Example 1 First, the optical fiber fixture shown in FIG. 1 of the present invention and a conventional optical fiber fixture sample shown in FIGS. 5A and 5B were prepared as comparative examples.

To obtain the optical fiber fixture shown in FIG.
As shown in FIG. 3, four notches are formed in the recess of the ferrule support made of stainless steel, the ferrule made of zirconia ceramics is inserted into the recess, and then caulking is performed to bring the ferrule and the ferrule support into non-contact areas. Were fixed so that four points were formed.

Further, as a comparative example, in order to form an optical fiber fixture having a bottomed specification shown in FIG. 5A and a bottom floating specification shown in FIG. 5B, a ferrule made of zirconia ceramic is supported by a ferrule made of stainless steel in the same manner as described above. The ferrule and the ferrule support were fixed by press fitting into the recess of the body. In the bottom floating specification optical fiber fixture as shown in FIG. 5B, the bottom surface of the concave portion of the ferrule support and the end surface of the ferrule are 0.10 mm.

In each of the sample of the present invention and the comparative example, the outer diameter of the ferrule was 2.5 mm, the length L was 10.5 mm, the diameter of the pores was 0.126 mm, and the diameter of the through holes formed in the ferrule support was It was 1.0 mm.

20 optical fiber pigtail samples were prepared by inserting and fixing optical fibers into the above-mentioned three types of optical fiber fixture samples with an adhesive and polishing the end face of the ferrule to finish polishing.
Individually made.

Next, each sample was shaved into a half cross section, and the presence or absence of air pockets was checked with a stereoscopic microscope at a magnification of 10 times.

The results are shown in Table 1.

[0052]

[Table 1]

In the sample with the bottomed specification of the comparative example 1 in which the ferrule of the comparative example was press-fitted and fixed to the ferrule support, similarly, in the sample with the bottom floating specification of the comparative example 2, air traps occurred in 7 pieces. It was

On the other hand, no air pocket was generated in the sample having the non-contact portion of the present invention.

(Embodiment 2) Next, the above-mentioned three kinds of optical fiber fixture samples are separately prepared, an optical fiber is inserted to obtain an optical fiber pigtail, and a pair of optical fiber pigtails are inserted and fixed in a split sleeve. Then, it was incorporated into the optical fiber connector.

The connection loss is measured beforehand and the temperature is -40 ° C.
A heat cycle test is performed under the temperature condition of -25 ° C to + 85 ° C (30 minutes to 5 minutes to 30 minutes) for one cycle of 65 minutes.
After 0 cycles, the connection loss was measured again after the test and the difference was calculated.

The results are shown in Table 2.

[0058]

[Table 2]

From Table 2, it can be seen that in the sample with the bottomed specification which is the comparative example 1, the average value of the connection loss fluctuation is 0.56 dB, the variation is 1.55 dB, and the sample with the bottom floating specification which is the comparative example 2 is the connection loss. It can be seen that the average value of the fluctuations is 1.56 dB and the variation is 2.53 dB, which is a large decrease.

On the other hand, in the sample of the present invention, the average value of the connection loss fluctuation was 0.01 dB and the variation was 0.02 dB, and the connection loss fluctuation was very small, and stable characteristic values were shown in the long-term reliability.

[0061]

According to the optical fiber fixture of the present invention, the recess of the ferrule support of the optical fiber fixture comprises a ferrule and a ferrule support having a recess for fitting the outer periphery of the rear end of the ferrule. Since at least two non-contact parts are provided in the optical fiber, the optical fiber and the ferrule support can be firmly adhered, and air bubbles of the adhesive do not occur. Therefore, damage to the optical fiber is prevented and reliability is improved. A high fiber optic pigtail can be obtained.

Further, according to the optical fiber fixture of the present invention, since at least two notches are provided on the outer peripheral surface of the recess of the ferrule support, the ferrule and the ferrule support are stably caulked and fixed. be able to.

Further, according to the optical fiber fixture of the present invention, since the adhesive reservoir is provided in the recess of the ferrule support, the adhesive does not stick out from the end face of the support, and the insertability into the sleeve is improved. It does not hurt.

Furthermore, according to the optical fiber fixture processing method of the present invention, the rear end of the ferrule is inserted into the recess of the ferrule support, and the notch of the ferrule support is caulked to the outer periphery of the ferrule. Since it is fixed, it is not necessary to process the ferrule support with high accuracy, and it is possible to effectively prevent chipping of the ferrule, occurrence of cracks, and deformation of the ferrule support.

Furthermore, according to the optical fiber pigtail using the optical fiber fixture of the present invention, it is not necessary to process the ferrule support with high precision, and there are cracks in the ferrule, cracks and deformation of the ferrule support. Further, the problem of press-fitting does not occur, and further, when the optical fiber pigtail is used, the air pocket of the adhesive does not occur, so that the optical fiber pigtail having high reliability can be obtained.

[Brief description of drawings]

1A is a front view showing an embodiment of an optical fiber fixture of the present invention, and FIG. 1B is a sectional view taken along line XX of FIG. 1A.

2 (a) and 2 (c) are front views showing another embodiment of the optical fiber fixture of the present invention, and FIG. 2 (b) is the same figure (a).
3 is a cross-sectional view taken along line YY of FIG.

FIG. 3 is a schematic cross-sectional view showing an assembling method of the optical fiber fixture of the present invention.

FIG. 4 is a sectional view showing an optical fiber pigtail using the optical fiber fixture of the present invention.

FIG. 5 is a sectional view showing a conventional optical fiber connector.

6A and 6B are cross-sectional views showing a conventional optical fiber fixture.

[Explanation of symbols]

1: Ferrule 1a: pore 1b: tapered portion 2: Ferrule support 2a: concave portion 2b: Through hole 2c: Notch 2d: Non-contact part 2e: adhesive reservoir 3: Optical fiber fixture 4: Taper ring 5: Caulking sleeve 5a: nail 6: Lower jig 7: Optical fiber 8: Adhesive 9: Optical fiber pigtail

Claims (5)

[Claims] 1. An optical fiber fixing comprising a ferrule having a fine hole for inserting an optical fiber, and a ferrule support having a recess for fitting the outer periphery of the rear end of the ferrule and a through hole for inserting the optical fiber. An optical fiber fixing tool, characterized in that at least two non-contact portions are provided in the concave portion of the ferrule support member with respect to the outer periphery of the ferrule. 2. The optical fiber fixture according to claim 1, wherein at least two notches are provided on the outer periphery of the recess of the ferrule support. 3. The optical fiber fixture according to claim 1, wherein an adhesive agent reservoir is provided in the recess of the ferrule support. 4. The ferrule support according to claim 1, wherein the rear end of the ferrule is inserted into the recess of the ferrule support, and the notch of the ferrule support is caulked to fix the outer periphery of the ferrule. Method for assembling optical fiber fixture. 5. An optical fiber pigtail using an optical fiber fixture according to any one of claims 1 to 3, wherein an optical fiber is inserted and held in the fine hole of the ferrule and the through hole of the ferrule support.