JP3493281B2 - Optical fiber ferrule and optical fiber connector using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber ferrule for holding an end portion of an optical fiber and an optical fiber connector using the same.

[0002]

2. Description of the Related Art In recent years, information transmission by optical signals using optical fibers has been widely performed. At this time, an optical connector is used to connect the optical fibers to each other.

As shown in FIGS. 6 and 7, a concrete structure of an optical connector is such that a flange member 2 made of metal or resin is bonded to one end of a ferrule 1 having a pore 1a, and the pore of the ferrule 1 is formed. One end of the optical fiber 5 is inserted into and fixed to 1a, the plug housing 4 is provided around the flange member 2 to form the connector plug 11, and the pair of connector plugs 11 is inserted from both ends of the adapter 12 to obtain the ferrule 1
The optical signal is transmitted by bringing the end faces of the optical fiber 5 provided in the above into contact with each other.

By the way, the ferrule 1 is made of ceramics such as zirconia and precisely manufactured so that the concentricity of the pores 1a with respect to the outer diameter is high. It is difficult to completely match with each other, and it is unavoidable that a misalignment of 1.4 μm or less occurs, and this misalignment causes a connection loss.

Therefore, even if the ferrule 1 is misaligned, the connection loss is reduced by making the misalignment directions of the pair of ferrules 1 abutting each other coincide.

For example, as shown in FIG. 10, four grooves 2c are formed in the flange member 2 of the ferrule 1 at 90 ° intervals, and an engaging portion 4a consisting of two protrusions is formed on the inner surface of the plug housing 4. The ferrule 1 is formed by forming the connector plug 11 by engaging them with each other.
Be able to hold in the rotated position every °. Then, while rotating the ferrule 1 by 90 °, the connection loss is measured at each position and finally assembled at the position where the loss is minimum.

[0007]

However, the above-mentioned FIG.
With the connector plug 11 as shown in (1), the ferrule 1 can be rotated only every 90 °, so that it could not be set at the optimum position. Also, rotate by 90 degrees and
After measuring the number of times, a total of 5 to set the position where the loss is minimum
It required a lot of assembly work, which was very troublesome.

[0008]

SUMMARY OF THE INVENTION In view of the above, the present invention is a ferrule having a hole for inserting and fixing an optical fiber in the center, and chamfering the outer surface of the ferrule, the direction of the misalignment position of the hole. The display part is formed in a notch shape. Further, a flange member is provided at one end of the ferrule having a pore for inserting and fixing the optical fiber in the center, and at the rear end of the outer peripheral side surface of these ferrules,
The decentering position direction display portion of the pores is formed in a notch shape, and the decentering position direction display portion is also formed on the outer surface of the flange member. Further, the optical fiber connector comprises a connector plug in which one end of an optical fiber is inserted and fixed to the ferrule having a hole in the center and a plug housing is provided around the ferrule, and an adapter for inserting the connector plug. The plug housing is provided with a misalignment position direction display portion of the end face of the optical fiber fixed to the ferrule. Further, the misalignment position direction display portion is formed within a range of ± 30 ° with respect to the actual misalignment direction of the pore or the optical fiber end face.

[0009]

Furthermore, the present invention is an optical fiber connector having one end of an optical fiber inserted and fixed to a ferrule having a hole in the center, and a plug housing provided around the ferrule, wherein the optical fiber fixed to the ferrule is provided. It is characterized in that the misalignment position direction display portion of the fiber end face is formed in the plug housing.

That is, if the pore or the misalignment position direction display portion of the end face of the optical fiber is formed in advance in any one of the ferrule, the flange member and the plug housing, the pair of light beams are aligned so that the misalignment directions coincide with each other. By abutting the connectors with each other, the connection loss can be minimized.

In the present invention, the misalignment direction means the direction of the center point of the pore or the optical fiber end face viewed from the center point of the ferrule. In the present invention, the misalignment position direction display unit is basically unified by forming it on the extension line in the direction of the center point of the pore or the optical fiber end face viewed from the center point of the ferrule. However, conversely, the misalignment position direction display portion may be formed in the direction opposite to the direction of the pore or the center point of the end face of the optical fiber as viewed from the center point of the ferrule to be unified. In either case, it is important to clearly define and unify the positional relationship between the misalignment direction and the misalignment position direction display portion.

Further, the present invention is characterized in that the misalignment position direction display portion is formed within a range of ± 30 ° with respect to the actual misalignment direction of the pore or the end face of the optical fiber.

That is, it has been found that the connection loss can be sufficiently reduced by forming the misalignment position direction display portion within ± 30 ° with respect to the actual misalignment direction. for that reason,
Since it is not necessary to completely align the misalignment direction and the position of the identification display portion, it is possible to easily manufacture.

[0015]

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

First, as a reference example, a single optical fiber ferrule is shown in FIG. The ferrule 1 is a cylindrical body having a pore 1a for inserting and fixing an optical fiber, and has a cone portion 1b for facilitating the insertion of the optical fiber at the rear end side of the pore 1a and has a tip end side. A chamfer 1c is formed on the outer peripheral portion.

Further, on the outer peripheral side surface of the ferrule 1, a misalignment position direction display portion 1d made of a marking is formed. That is, as described above, it is inevitable that the center of the pore 1a is slightly deviated from the center of the ferrule 1, but the direction of this misalignment is measured in advance, and the misalignment position direction display portion 1d is measured in that direction. Is formed.

Therefore, when the ferrule 1 is used to construct an optical connector, the misalignment position direction display portion 1d is formed.
If the pair of ferrules 1 are brought into contact with each other so that they coincide with each other, the misalignment directions of the ferrules coincide with each other, whereby the connection loss can be reduced.

As the marking forming the misalignment position direction display portion 1d, various means such as writing with a pen, coating with paint, sticking a sticker or the like can be used. Also, as will be described in detail later,
When the ferrule 1 is joined to the flange member 2 and the plug housing 4 and the flange member 2 and the plug housing 4 are also provided with the misalignment position direction display portion, finally the misalignment position direction of the ferrule 1 itself is formed. Since the display unit 1d is not necessary, the marking can be erased and removed with, for example, ethanol.

[0020]

As another embodiment of the misalignment position direction display portion 1d, as shown in FIG. 2A, a chamfer 1c may be provided with a notch to form the misalignment position direction display portion 1d. . If it is formed at this position, dust and the like existing on the tip surfaces can be escaped when the tip surfaces of the ferrule 1 are butted and connected to each other.

Further, as another embodiment of the misalignment position direction display portion 1d, as shown in FIG.
It is also possible to form a misalignment position direction display portion 1d formed by a notch at the rear end portion of the outer peripheral side surface of In this case, as will be described later, when the flange member 2 is formed by insert molding of resin, the misalignment position direction display portion 1 including a notch is formed.
d can be made to act as a locking portion.

[0023]

[0024]

The material of the ferrule 1 is as follows.
Resins, metals, ceramics, etc. are used, but ceramics containing zirconia as a main component are most suitable. Specifically, ZrO ₂ as a main component, Y ₂ O ₃ as a stabilizer,
Partially stabilized zirconia ceramics containing mainly tetragonal crystals are used because they contain at least one of MgO, CaO, CeO ₂ , Dy ₂ O _{3 and the} like. Further, when manufacturing such a ferrule 1 made of zirconia ceramics, it is obtained by using the above-mentioned raw material powder, molding it into a predetermined shape by extrusion molding, injection molding or the like, and then firing it.

When the misalignment position direction display portion 1d is formed on the obtained ferrule 1, the ferrule 1 is placed on the jig 20 having the V groove 21 as shown in FIG. 3 (a). When the ferrule 1 is rotated while photographing the pores 1a with a camera or the like, as shown in the monitor screen in FIG. 3B, the inner diameter line is moved due to the misalignment of the pores 1a, and this is shifted to the maximum. At this point, the rotation of the ferrule 1 may be stopped and the misalignment position direction display portion 1d may be formed at that position.

By doing so, the misalignment position direction display portion 1d can be formed on the extension line in the direction of the center point of the pore 1a when viewed from the center point of the ferrule 1.

Next, a first embodiment will be described.

As shown in FIG. 4, a flange member 2 having a through hole 2a is provided at the rear end of the ferrule 1 described above,
These ferrules 1 and / or flange members 2 have pores 1
It is also possible to form the misalignment position direction display portion of a.

The ferrule 1 has a misalignment position direction display unit 2
When forming c, it may be performed in the same manner as in FIG.

Further, when the misalignment position direction display portion 2c is formed on the flange member 2, as shown in FIGS. 5 (a) and 5 (b), one groove or notch is formed on the outer peripheral surface of the flange member 2. 5 (c), two or more grooves are provided to change the width, or a protrusion is formed as shown in FIG. 5 (d). As shown in FIG. 5 (g), the outer peripheral surface has a polygonal shape to form a groove or protrusion, or the outer peripheral surface has a polygonal shape to partially deform the shape, or the marking is performed in the same manner as in the reference example. It can have various structures such as application.

By thus forming the misalignment position direction display portions 1d and 2c on the ferrule 1 and / or the flange member 2, when the end faces of the pair of ferrules 1 holding the optical fibers are brought into contact with each other. , The connection loss can be reduced by matching the misalignment directions of the two.

The flange member 2 is made of metal or resin. Then, as shown in FIG. 4 (a), the ferrule 1 and the flange member 2 can be joined by pressing the ferrule 1 into the recess 2b of the flange member 2, or by joining the two with an adhesive. As shown in FIG. 4 (b), the flange member 2 may be formed of resin and joined to the ferrule 1 by insert molding.

When the flange member 2 is formed by resin insert molding as shown in FIG. 4 (b), as described above, the misalignment position direction display portion 1 which is a notch in the ferrule 1 is formed.
If d is formed and this portion is embedded in the flange member 2, the misalignment position direction display portion 1d can also serve as the locking portion.

The specific method for producing the ferrule 1 having the flange member 2 as shown in FIG. 4 is as follows.

First, a ferrule 1 having a misalignment position direction display portion 1d as shown in the reference example and a flange member 2 provided with a misalignment position direction display portion 2c in advance are prepared, and both misalignment position direction indications are displayed. It suffices that the parts 1d and 2c match each other.

As another method, the ferrule 1 not provided with the misalignment position direction display portion 1d is joined to the flange member 2 not provided with the misalignment position direction display portion 2c, and in this state as shown in FIG. Detect the misalignment direction by the method shown,
It is also possible to form the misalignment position direction display portion 2c on the flange member 2.

As yet another method, the misalignment direction is detected by the method shown in FIG. 3 for the ferrule 1 which does not have the misalignment position direction display portion 1d, and the ferrule 1 is held in this state. The flange member 2 provided with the misalignment position direction display portion 2c in advance may be joined so as to match the misalignment direction.

Next, a second embodiment will be described.

As shown in FIGS. 6 and 7, a flange member 2 is provided at the rear end of the ferrule 1 as described above, and the flange member 2 is placed in the plug housing 4 while being biased by a spring 3 or the like. A mounting member 6 such as a screw is provided on the outer periphery of the plug housing 4, and the end face of the optical fiber 5 is inserted and fixed in the fine hole 1a of the ferrule 1 to form a connector plug 11
Make up. On the other hand, the adapter 12 is provided with a sleeve 8 for inserting the above-mentioned ferrule and a screw 12a that matches the mounting member 6.

Now, by inserting the connector plugs 11 from both sides of the adapter 12 and inserting the ferrule 1 into the sleeve 8, the end faces of the ferrules 1 are brought into contact with each other, and fixed by the attaching member 6, an optical connector is obtained. Can be configured.

In the plug housing 4, the misalignment position direction display portion 4b showing the misalignment direction of the end face of the optical fiber 5 is shown.
Is formed on the adapter 12, while the adapter 12 has a groove 1
2b, and the plug housing 4 is provided in this groove 12b.
By engaging and inserting the misalignment position direction display portion 4b, the misalignment directions of the end faces of the optical fibers 5 can be matched with each other, and the connection loss can be reduced.

In order to manufacture such an optical connector, the ferrule 1 alone or the ferrule 1 provided with the flange member 2 shown in the above-described reference example and the first embodiment is used. That is, the ferrule 1 provided with the misalignment position direction display portions 1d and 2c indicating the misalignment direction of the pores 1a is used in advance, and the plug housing 4 is preliminarily formed with the protrusion forming the misalignment position direction display portion 4b. Then, it is only necessary to assemble so that both the misalignment position direction display portions match.

For example, a misalignment position direction indicating portion 2c such as a groove or a protrusion is formed on the outer peripheral surface of the flange member 2 as shown in FIG. 5, and the inner peripheral surface of the plug housing 4 is engaged with the same. The part 4a may be formed and the both may be engaged.

In this way, the pores 1 of the ferrule 1
The misalignment direction of a and the misalignment position direction display portion 4b of the plug housing 4 can be matched, and as a result, the misalignment direction of the end face of the optical fiber 5 held in the pore 1a and the misalignment of the plug housing 4 can be made. The shift position direction display portions 4b can be matched.

Strictly speaking, a gap between the fine hole 1a and the optical fiber 5 or a misalignment of the core of the optical fiber 5 itself is conceivable. The misalignment direction of 1a and the misalignment direction of the end face of the optical fiber 5 held therein are substantially the same.

In the above-mentioned reference examples and the first and second embodiments, the misalignment direction of the pore 1a or the end face of the optical fiber 5 and the misalignment position direction display portions 1d, 2c, 4b are matched. However, in the present invention, it is not always necessary to completely match the two, and the angle between them is ± 30 ° C.
It should be within the range.

That is, the ferrule 1 or the connector plug 4
8, the angle formed by the actual misalignment position direction display portion 1d with respect to the direction of the center point B of the pore 1a viewed from the center point A of the ferrule 1, that is, the true misalignment direction C, as shown in FIG. It has been found that the connection loss can be sufficiently reduced if θ is in the range of −30 to 30 °.

Therefore, in the steps of forming the misalignment position direction display portions 1d, 2c, 4b and the step of joining the ferrule 1 and the flange member 2 in the above manufacturing process,
Since it may be set within the range of 30 °, it is not necessary to perform strict alignment, and the manufacturing process can be simplified.

In the connector plug 11, since the ferrule 1, the flange member 2 and the plug housing 4 are assembled by being joined or engaged with each other, alignment accuracy and clearance between the members are generated. Therefore, including the alignment accuracy and clearance, the misalignment position direction display portion 4b of the plug housing 4 should be formed within ± 30 ° from the misalignment direction of the end face of the optical fiber 5 in the ferrule 1. Good.

Further, as shown by the broken line in FIG. 8, if a misalignment position direction display portion 1d 'having a clearly distinguishable shape is formed at a position opposite to the misalignment position direction display portion 1d, the misalignment position direction display portion 1d' can be formed. The shift direction can be clearly identified.

Here, the connection loss when the angle θ formed by the misalignment position direction display portion 1d with respect to the true misalignment direction C was changed was calculated as follows.

First, as Comparative Example 1, the concentricity is 1.4 μm.
When the misalignment direction is not adjusted at all using the ferrule of m, as shown in FIG.
Since it is not known where the end faces of the two optical fibers 5 are within a circle having a diameter of 1.4 μm with respect to the center A of the ferrule 1 (the hatched portion in the figure), the maximum misalignment between the two is 1.4.
μm.

The connection loss L at this time is L = 4.34 (d / ω) ² , where d: misalignment amount ω: spot size = core diameter / 2 × 1.1 = 5.5
Since it is expressed in [μm], the maximum connection loss L _max is L _max = 4.34 × (1.4 / 5.5) ² = 0.28 [dB].

Further, as Comparative Example 2, in which the ferrule 1 can be adjusted at 90 ° intervals as shown in FIG. 10, the end faces of the two optical fibers 5 have diameters as shown in FIG. 9 (b). It comes within the range of a sector with a central angle of 90 ° in a circle of 1.4 μm (the shaded area in the figure), and the maximum misalignment in this case is the distance between the ends of the sector, where d = 1.4 / 2 × sin 45 ° × 2 = 0.990 [μm]. Therefore, the maximum connection loss L _max is L _max = 4.34 × (0.99 / 5.5) ² = 0.14 [dB].

On the other hand, in the embodiment of the present invention, in each connector plug 4, since the misalignment direction is within ± 30 ° from the misalignment position direction display portion 4b, the end faces of the two optical fibers 5 are As shown in FIG. 9 (c), a circle with a diameter of 1.4 μm comes within the range of a fan shape with a central angle of 60 ° (the shaded area in the figure), and the maximum misalignment amount in this case is a fan shape. The distance between the two ends becomes d = 1.4 / 2 × sin30 ° × 2 = 0.70 [μm]. Therefore, the maximum connection loss L _max is L _max = 4.34 × (0.7 / 5.5) ² = 0.07 [dB].

Further, in the embodiment of the present invention, when the misalignment direction and the misalignment position direction display portion 4b are completely matched, it is 2
As shown in FIG. 9D, the end faces of the two optical fibers 5 come to be on a certain radius of a circle having a diameter of 1.4 μm, and the maximum misalignment amount between them is 0.7 μm.

Therefore, the maximum connection loss L _max is L _max = 4.34 × (0.7 / 5.5) ² = 0.07 [dB].

The above is summarized as shown in Table 1. From this result, in the embodiment of the present invention in which the angle θ of the misalignment position direction display portion 4b with respect to the true misalignment direction is within ± 30 °, the maximum The connection loss can be set to 0.07 dB, and can be markedly reduced as compared with the comparative example.

Moreover, the maximum connection loss is the same in the case where the misalignment position direction display portion 4d and the misalignment direction angle θ are set to 30 ° and when the two are completely matched (θ = 0 °). I also understand. Therefore, the misalignment position direction display unit 4
It is not necessary to completely match the direction of misalignment with d.
It should be kept within °.

[0061]

[Table 1]

[0062]

As described above, according to the present invention, there is provided a ferrule having a hole for inserting and fixing an optical fiber at the center, and the misalignment position direction display portion of the hole is formed on the outer surface. Therefore, if the pair of ferrules are brought into contact with each other so that the misalignment directions coincide with each other, the connection loss can be minimized.

Further, the present invention is an optical fiber connector in which one end of an optical fiber is inserted and fixed in a ferrule having a small hole in the center and a plug housing is provided around the ferrule, and the optical fiber fixed to the ferrule is provided. By forming the misalignment position direction display portion of the fiber end face on the plug housing, by abutting the pair of optical connectors so that the misalignment direction is coincident,
Connection loss can be minimized.

Further, according to the present invention, it is necessary to perform precise alignment by forming the misalignment position direction display portion within a range of ± 30 ° with respect to the misalignment direction of the pore or the optical fiber end face. Since it does not exist, the manufacturing process can be simplified.

Therefore, according to the present invention, it is possible to inexpensively provide a high-performance optical connector with little connection loss.

[Brief description of drawings]

FIG. 1 shows a reference example of an optical fiber ferrule of the present invention, (a) is an end view and (b) is a side view.

FIG. 2A is a sectional view, FIG. 2B is a side view, and FIGS. 2C to 2G are various reference examples of XX line sectional views of an embodiment of an optical fiber ferrule of the present invention. FIG.

FIG. 3 is a diagram for explaining a method of forming the misalignment position direction display portion on the optical fiber ferrule of the present invention.

4A and 4B are longitudinal sectional views showing another embodiment of the optical fiber ferrule of the present invention.

5 (a) to 5 (g) are diagrams showing various examples of end views of the optical fiber ferrule shown in FIG.

FIG. 6 is a perspective view showing an optical fiber connector of the present invention.

FIG. 7 is a vertical sectional view showing an optical fiber connector of the present invention.

FIG. 8 is a diagram for explaining the misalignment direction of the ferrule 1.

9 (a) to 9 (d) are views for explaining the positional deviation amount of a pair of optical fiber end faces in the optical fiber connectors of the present invention and the comparative example.

FIG. 10A is a cross-sectional view of a connector plug forming a conventional optical fiber connector, and FIG. 10B is a side view showing a ferrule used for this.

[Explanation of symbols]

1: Ferrule 1a: pore 1d: misalignment position direction display section 2: Flange member 3: Spring 4: Plug housing 4b: misalignment position direction display section 5: Optical fiber 6: Mounting member 8: Sleeve 11: Connector plug 12: Adapter

Continuation of the front page (56) Reference JP-A 63-27806 (JP, A) JP-A 1-223404 (JP, A) JP-A 6-51165 (JP, A) JP-A 63-17206 (JP , A) JP-A-62-11808 (JP, A) JP-A-61-129605 (JP, A) Actual opening flat 8-627 (JP, U) Actual opening 55-77207 (JP, U) Actual opening flat 7-5106 (JP, U) Actual development Sho 63-20109 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G02B 6/36 G02B 6/38

Claims (4)

(57) [Claims] 1. A ferrule having a small hole for inserting and fixing an optical fiber in the center, wherein an outer surface of the ferrule is chamfered, and the misalignment position direction display portion of the small hole is formed in a cutout shape . An optical fiber ferrule characterized by being formed. Wherein a flange member at one end of the ferrule having a pore for inserting fixing the optical fiber in the center, the upper
At the rear end of the outer peripheral side surface of the ferrule, a display portion for indicating the misalignment position of the pore is formed in a cutout shape , and
A misalignment position direction indicator is also formed on the outer surface of the lunge member.
Optical fiber ferrule, characterized in that the. 3. An optical fiber with one end inserted and fixed in a ferrule having a hole in the center according to claim 1 or 2, and a connector plug having a plug housing around this ferrule, and this connector plug is inserted. An optical fiber connector comprising an adapter, wherein the plug housing is provided with a misalignment position direction display portion of an end face of the optical fiber fixed to the ferrule. 4. The misalignment position direction display portion is ± 30 ° with respect to the actual misalignment direction of the pore or the optical fiber end face.
The optical fiber connector according to claim 1, wherein the optical fiber connector is formed within the range.