JP2013033200A - Ferrule, optical fiber holding component, optical fiber pigtail, and optical receptacle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a possibility that an optical fiber to be inserted may be damaged.SOLUTION: A ferrule 1 with a through-hole 11 includes: a fist tapered part 31 of which inside diameter is gradually reduced as its heading from one end side toward the other end side; an intermediate part 32 of which inner peripheral surface is continuously provided at the other end side of the first tapered part 31 and which has a constant inside diameter; and a second tapered part 33 of which inner peripheral surface is continuously provided at the other end side of the intermediate part 32 and of which inside diameter is gradually reduced as its heading from one end side toward the other end side. The intermediate part 32 is provided between the first tapered part 31 and the second tapered part 33, so that an optical fiber 2 is roughly positioned in the first tapered part 31, and the insertion direction of the optical fiber 2 can be adjusted in the intermediate part 32. This constitution can prevent the optical fiber 2 from being pressed against the second tapered part 33 so as to reduce a possibility of damaging the optical fiber 2.

Description

  The present invention relates to a ferrule, an optical fiber holding component using the same, an optical fiber pigtail, and an optical receptacle.

  A ferrule is known as a part for inserting and fixing an optical fiber. As this ferrule, the thing of patent document 1 is mentioned, for example. The ferrule described in Patent Document 1 includes a through hole penetrating from one end to the other end of a cylindrical body, and has a tapered shape in which the opening of the through hole is widened at one end where the optical fiber is inserted. ing. As described above, since the opening has a tapered shape, the optical fiber can be guided near the center of the through hole when the optical fiber is inserted into the through hole.

JP 2008-304731 A

  However, in the ferrule described in Patent Document 1, even if the optical fiber can be easily positioned using the tapered opening, the insertion direction of the optical fiber with respect to the through hole cannot be adjusted. In some cases, the surface of the optical fiber is rubbed against the inner peripheral surface of the through hole by pushing the optical fiber in the wrong direction instead of the through direction. As a result, the optical fiber may be damaged.

  The ferrule of one embodiment of the present invention has a through hole in which an optical fiber is inserted and fixed from one end side, and the through hole has a first taper whose inner diameter decreases from the one end side toward the other end side. An intermediate portion having a constant inner diameter, and an inner peripheral surface continuously provided on the other end side of the intermediate portion. In addition, a second taper portion having an inner diameter that decreases from the one end side toward the other end side is provided.

  An optical fiber holding component according to an embodiment of the present invention includes the ferrule and a holder that holds the ferrule so as to surround one end of the ferrule.

  An optical fiber pigtail according to an embodiment of the present invention includes the optical fiber holding component and an optical fiber that is inserted into and fixed to the ferrule.

  An optical receptacle according to an embodiment of the present invention includes the optical fiber pigtail and a sleeve provided at the other end of the ferrule into which a plug ferrule is inserted.

According to the ferrule and the optical fiber holding component of one embodiment of the present invention, since the intermediate portion is provided between the first taper portion and the second taper portion, the optical fiber is positioned in the first taper portion. The insertion direction of the optical fiber can be easily adjusted to match the penetration direction of the through hole by pushing the optical fiber inside the intermediate portion having a constant inner diameter. Thereby, it can suppress that the surface of an optical fiber rubs with the internal peripheral surface of a through-hole by pushing an optical fiber in the wrong direction with respect to a through-hole. As a result, the possibility that the optical fiber is damaged can be reduced.

  According to the optical fiber pigtail and the optical receptacle of the embodiment of the present invention, since the ferrule includes a reduced possibility of damaging the optical fiber, it is possible to reduce the damage of the mounted optical fiber and to improve the reliability. High optical signal transmission can be performed.

It is sectional drawing which shows the ferrule of one Embodiment of this invention. It is a partial expanded sectional view which expands and shows the area | region A of the ferrule shown in FIG. It is sectional drawing which shows the member for optical component holding | maintenance of one Embodiment of this invention. It is sectional drawing which shows the optical receptacle of one Embodiment of this invention. It is a partial expanded sectional view of the ferrule of one modification. It is sectional drawing which shows the ferrule of another modification. It is the elements on larger scale which expand and show the area | region B of the ferrule shown in FIG. It is sectional drawing which shows the optical fiber holding component using the ferrule shown in FIG.

  Hereinafter, a ferrule 1, an optical fiber holding component 10, and an optical receptacle 100 according to an embodiment of the present invention will be described with reference to the drawings. Note that all the drawings are schematic and do not strictly represent actual dimensions.

<Configuration of ferrule 1>
FIG. 1 is a cross-sectional view showing a ferrule 1 according to an embodiment of the present invention. FIG. 2 is a partial enlarged cross-sectional view in which a region A of the ferrule shown in FIG. 1 is enlarged. 1 and FIG. 2, the ferrule 1 of this embodiment is a substantially cylindrical member, and the optical fiber 2 is inserted and fixed from one end side (X1 side in FIG. 1). A through hole 11 is provided. A chamfered portion 12 is provided on the outer peripheral portion on the other end side (X2 side in FIG. 1) located on the opposite side to the one end side where the optical fiber 2 is inserted. Thereby, when inserting the ferrule 1 into an external apparatus from the other end side, it can insert smoothly by suppressing that the corner | angular part of the ferrule 1 contacts an external apparatus.

  As the ferrule 1, for example, zirconium oxide (zirconia), aluminum oxide (alumina), mullite, silicon nitride, silicon carbide, aluminum nitride or the like, ceramics containing these as main components, or glass ceramics such as crystallized glass, etc. Can be used. In particular, in order to make the ferrule 1 excellent in environmental resistance and toughness, it is preferable to mainly contain zirconia.

  The dimensions of the ferrule 1 will be described. Here, it is assumed that the optical fiber 2 used for the ferrule 1 is an optical fiber having an outer diameter of 125 μm defined by the JIS standard or the TIA / EIA standard. In this case, the outer diameter of the ferrule 1 can be set to 1 to 3 mm and the length to 6 to 13 mm, for example.

  The through hole 11 is provided so as to penetrate the cylindrical main body of the ferrule 1 along the central axis and open at one end and the other end. This through hole 11 is provided for the optical fiber 2 to be inserted and fixed. As shown in FIG. 2, the through-hole 11 can be roughly divided into an optical fiber introducing portion 3 located on one end side of the ferrule 1 and an optical fiber holding portion 4 located on the other end side of the ferrule 1. it can.

  The optical fiber introduction part 3 is a part that functions as a guide when the optical fiber 2 is inserted into the optical fiber holding part 4. The optical fiber introducing portion 3 is formed on one end side of the ferrule 1. The optical fiber introducing portion 3 has an inner diameter that decreases from one end side of the ferrule 1 toward the other end side. In other words, the optical fiber introducing portion 3 includes a first taper portion 31 formed on one end side of the ferrule 1, an intermediate portion 32 formed continuously on the other end side of the first taper portion 31, and an intermediate portion 32. It has the 2nd taper part 33 formed continuously in the other end side.

  The first taper portion 31 is a portion where the optical fiber 2 is inserted first, and opens at one end of the ferrule 1. The first taper portion 31 is a portion for roughly positioning the insertion position of the optical fiber 2. Further, it is also a part filled with an adhesive for fixing the optical fiber 2 and the ferrule 1 after the optical fiber 2 is inserted. The first taper portion 31 has an inner peripheral surface that is inclined with respect to the through direction of the through hole 11 when viewed in a cross section in a cross section parallel to the through direction of the through hole 11. Specifically, the ferrule 1 has an inner peripheral surface that decreases in inner diameter from one end side toward the other end side. Therefore, since the first tapered portion 31 functions as a guide, the optical fiber 2 can be easily inserted into the intermediate portion 32 by inserting the optical fiber 2 into the first tapered portion 31.

  As for the 1st taper part 31 in this embodiment, the shape of the internal peripheral surface when it cross-sectionally views is each linear shape. The angle a (hereinafter referred to as the first angle a) formed by the extension lines of these two straight lines may be set to, for example, about 60 ° to 120 °. When the first angle a is 60 ° or more, a sufficient space can be secured between the surface of the first taper portion 31 and the optical fiber 2. Therefore, since the adhesive can be stably filled in the space after the optical fiber 2 is mounted, the bonding strength between the optical fiber 2 and the ferrule 1 can be increased. In addition, when the first angle a is 120 ° or less, the first tapered portion 31 can function stably as a guide. Therefore, the tip of the optical fiber 2 can easily move along the first taper portion 31, so that the optical fiber 2 can be stably inserted into the intermediate portion 32.

  The inner diameter of the end of one end of the first taper 31, that is, the opening surface of one end of the ferrule 1 is 0.5 to 1.5 mm, and the inner diameter of the end of the other end of the first taper 31 is 127 to 132 μm. The length of the 1 taper part 31 can be set to 0.3-2 mm.

  The intermediate part 32 is located between the first taper part 31 and the second taper part 33. The intermediate portion 32 has a constant inner diameter. Here, “the inner diameter is constant” means that a variation of a manufacturing error occurring when the ferrule 1 is manufactured can be ignored. The arithmetic average roughness Ra of the inner peripheral surface of the intermediate portion 32 is, for example, 0.05 μm or less. By setting the arithmetic average roughness Ra of the inner peripheral surface of the intermediate portion 32 to 0.05 μm or less, damage to the optical fiber 2 when the optical fiber 2 is inserted can be suppressed.

  Further, in order to easily insert the optical fiber 2 into the intermediate portion 32, the inner diameter of the end portion on the other end side of the first tapered portion 31 is the same as the inner diameter of the intermediate portion 32. In addition, in order to easily insert the optical fiber 2 into the second taper portion 33, the inner diameter of the end portion on one end side of the second taper portion 33 is the same as the inner diameter of the intermediate portion 32. Note that “the inner diameter is the same” means that the variation of the manufacturing error caused when the ferrule 1 is manufactured can be ignored.

The intermediate part 32 is a part for adjusting the insertion direction of the optical fiber 2 positioned roughly in the first taper part 31 in accordance with the penetration direction of the through hole 11. Specifically, even when the optical fiber 2 is bent when the optical fiber 2 is inserted into the first taper portion 31, the optical fiber 2 itself passes through the intermediate portion 32 having a constant inner diameter. Deflection can be corrected. Thereby, when inserting the optical fiber 2 in the 2nd taper part 33, it can suppress applying force in the direction shifted | deviated from the penetration direction of the through-hole 11 with respect to the front-end | tip of the optical fiber 2. FIG.

  Further, the intermediate portion 32 is formed to be longer than the first tapered portion 31. As a result, the optical fiber 2 is moved within the range of the intermediate portion 32 until the second tapered portion 33 having a smaller inner diameter than the first tapered portion 31 and the intermediate portion 32 is reached. The insertion direction of the can be confirmed. As a result, when inserting the optical fiber 2 in the 2nd taper part 33, it can suppress applying force in the wrong direction with respect to the front-end | tip of the optical fiber 2. FIG.

  The inner diameter of the intermediate portion 32 can be set to 127 to 132 μm, and the length of the intermediate portion 32 can be set to 1 to 5 mm, similarly to the end portion on the other end side of the first tapered portion 31.

  The second taper portion 33 is a portion for finely positioning the optical fiber 2 whose insertion direction is adjusted by passing through the intermediate portion 32, and is a cross-sectional view in a plane parallel to the penetration direction of the through hole 11. The inner peripheral surface is inclined with respect to the through direction of the through hole 11. Specifically, the second tapered portion 33 has an inner peripheral surface continuously provided on the other end side in the intermediate portion 32, and an inner peripheral surface such that the inner diameter decreases from one end side toward the other end side. Is formed. Thereby, the optical fiber 2 can be inserted into the optical fiber holding part 4 using the second taper part 33 as a guide.

  The second taper portion 33 is formed shorter in length than the first taper portion 31. This is because the optical fiber 2 passing through the second taper portion 33 is roughly positioned at the first taper portion 31 and is adjusted in the insertion direction at the intermediate portion 32. This is because the optical fiber 2 can be appropriately inserted into the optical fiber holding portion 4 even if the length 33 is short.

  As for the 2nd taper part 33 in this embodiment, the shape of the internal peripheral surface when it cross-sectionally views is each linear shape. The angle b (hereinafter referred to as the second angle b) formed by the extension lines of these two straight lines may be set to about 0.1 ° to 90 °. When the 2nd angle b is 0.1 degree or more, the 1st taper part 31 can be functioned stably as a guide. Moreover, when it is 90 degrees or less, it can suppress that an edge arises between the optical fiber holding | maintenance parts 4, and can insert the optical fiber 2 in the optical fiber holding | maintenance part 4 stably. The second angle b is set smaller than the first angle a. Thereby, the 2nd taper part 33 can align the optical fiber 2 with higher reliability compared with the 1st taper part 31.

  The inner diameter of the end portion on the one end side of the second taper portion 33 is 127 to 132 μm similarly to the intermediate portion 32, and the inner diameter of the end portion on the other end side of the second taper portion 33 is 125.5 to 127 μm. The length of 33 can be set to 0.001 to 1 mm.

  The optical fiber holding part 4 is a part for holding the optical fiber 2 inserted from the optical fiber introducing part 3. The optical fiber holding part 4 has an inner peripheral surface continuously provided on the other end side of the second taper part 33, and opens on the other end side of the ferrule 1. The optical fiber holding part 4 has a constant inner diameter. Here, “the inner diameter is constant” means that a variation of a manufacturing error occurring when the ferrule 1 is manufactured can be ignored. The arithmetic average roughness Ra of the inner peripheral surface of the optical fiber holding portion 4 is, for example, 0.05 μm or less. By setting the arithmetic average roughness Ra of the inner peripheral surface of the optical fiber holding portion 4 to 0.05 μm or less, damage to the optical fiber 2 when the optical fiber 2 is inserted can be suppressed. The inner diameter of the optical fiber holding portion 4 can be set to 125.5 to 127 μm, similarly to the inner diameter on the other end side of the second taper portion 33.

  In the ferrule 1 of the present embodiment, when the optical fiber 2 is inserted and fixed, the optical fiber 2 is roughly positioned in the first taper portion 31 and the optical fiber 2 is inserted in the intermediate portion 32. Therefore, when the optical fiber 2 is inserted into the second tapered portion 33, the tip of the optical fiber 2 is displaced from the penetrating direction of the through hole 11. It is possible to suppress applying force in any direction. As a result, the possibility that the optical fiber 2 is damaged when the optical fiber 2 is inserted into the ferrule 1 can be reduced.

  In addition, this invention is not limited to the above-mentioned embodiment, A various change, improvement, etc. are possible in the range which does not deviate from the summary of this invention. For example, in the present embodiment, the cross-sectional shape of the inner peripheral surface of the first tapered portion 31 of the ferrule 1 is two linear shapes, but is not limited thereto. For example, the first angle a of the first taper portion 31 may change in the middle of the first taper portion 31 as shown in a partially enlarged sectional view similar to FIG. Specifically, in the ferrule 1 of the example shown in FIG. 5, the first taper portion 31 is located on one end side, the first region 31a having an angle aa corresponding to the first angle a, and the other end side. And a second region 31b having an angle ab corresponding to the first angle a.

  In this case, it is preferable that the angle aa is larger than the angle ab. In such a case, the optical fiber 2 can be easily inserted more smoothly. Further, it is preferable that an R surface is provided between the second taper portion 33 and the optical fiber holding portion 4. Thereby, the optical fiber 2 can be more smoothly inserted from the second taper portion 33 to the optical fiber holding portion 4. As the dimension of the R surface, for example, the radius of curvature can be set to 0.001 to 5 mm.

<Manufacturing method of ferrule 1>
Below, the example of the manufacturing method of the ferrule 1 is demonstrated. In this example, a description will be given using ceramics (zirconia-based ceramics) mainly composed of zirconia as a constituent material of the ferrule 1.

  First, the molding material which comprises the molded object used as the prototype of the ferrule 1 is prepared. Specifically, the molding material is prepared by sufficiently mixing and pulverizing a mixed powder of zirconium oxide powder and yttrium oxide powder with a ball mill or the like, and then adding a binder to the pulverized material and mixing. The mixed powder is obtained by mixing 1 to 15% by mass of yttrium oxide powder with 85 to 99% by mass of zirconium oxide powder, particularly mixing 2 to 10% by mass of yttrium oxide powder with respect to 90 to 98% by mass of zirconium oxide powder. That is suitable. As the zirconium oxide powder, zirconium oxide having a purity of 95% or more, particularly 98% or more is suitable.

  Next, the molded object which has the through-hole 11 is obtained using the prepared molding material. Specifically, a molding material is filled in a cavity of a molding die having a cavity including a structure for molding the through hole 11, and press molding is performed at a predetermined pressure to obtain a molded body. The method for obtaining the molded body is not limited to the press molding described above, and a method such as injection molding, casting molding, cold isostatic pressing, or extrusion molding may be employed.

  Next, the obtained molded body is fired to obtain a sintered body. Specifically, after performing degreasing by putting the obtained molded body in a degreasing furnace at 500 to 600 ° C. for 2 to 10 hours, the degreased molded body is 1300 to 1500 ° C. in an oxygen atmosphere. A sintered body is obtained by firing for 0.5 to 3 hours.

Next, the 1st taper part 31, the intermediate part 32, and the 2nd taper part 33 are formed by performing grinding | polishing etc. with respect to the internal peripheral surface of the through-hole 11 of the obtained sintered compact. Specifically, the first taper portion 31, the intermediate portion 32, and the second taper portion 33 are formed by pressing a grindstone against the through-hole 11 while the ferrule 1 is rotated about the through-hole 11 as a rotation axis. At this time, it is preferable to use a grinding oil because polishing can be performed while suppressing an increase in inner surface roughness.

  As described above, the ferrule 1 can be manufactured.

<Configuration of Optical Fiber Holding Component 10 and Optical Fiber Pigtail 101>
As shown in a sectional view in FIG. 3, the optical fiber holding component 10 according to an embodiment of the present invention includes a ferrule 1 and a holder 5 provided so as to surround one end side of the ferrule 1. The optical fiber 2 is inserted and fixed in the optical fiber holding component 10 shown in FIG. The optical fiber holding component 10 becomes an optical fiber pigtail 101 by inserting and fixing the optical fiber 2.

  The optical fiber 2 is an optical fiber having an outer diameter of 125 μm defined by, for example, JIS standard or TIA / EIA standard, and is inserted into the through hole 11 of the ferrule 1 from one end side and exposed to the opening on the other end side. doing. In the optical fiber 2, the end surface on the other end side is arranged flush with the end surface on the other end side of the ferrule 1. The optical fiber 2 is drawn out from the end of one end side of the ferrule 1. The optical fiber 2 is fixed to the ferrule 1 by filling the first taper portion 31 with the adhesive 6. As the adhesive 6, for example, an epoxy resin adhesive can be used.

  A portion of the optical fiber 2 located outside the through hole 11 is covered with a covering member 21. As a material of the covering member 21, for example, a silicone resin, a nylon resin, an acrylic resin, or the like can be used.

  The holder 5 is a cylindrical member having a constant inner diameter and outer diameter. The holder 5 holds one end of the ferrule 1 so as to surround it together with a part of the optical fiber 2 drawn from one end of the ferrule 1. The holder 5 is provided such that the other end of the holder 5 holds the ferrule 1 and the tip of the holder 5 holds the optical fiber 2 via the covering member 21 in order to protect the drawn optical fiber 2. Yes. As a material of the holder 5, for example, a metal material such as stainless steel can be used.

  According to such an optical fiber holding component 10 of the present embodiment, the possibility that the optical fiber 2 is damaged when the optical fiber 2 is inserted into the ferrule 1 is reduced. The damage of the fiber 2 can be reduced and the transmission of the optical signal can be performed with high reliability.

<Configuration of Optical Receptacle 100>
As shown in a sectional view in FIG. 4, an optical receptacle 100 according to an embodiment of the present invention includes an optical fiber holding component 10, a sleeve 7 inserted on the other end side of the ferrule 1, and a gap from the sleeve 7. The case 8 is provided so as to surround the sleeve 7. The sleeve 7 is provided for inserting a plug ferrule (not shown). The optical receptacle 100 has a function of holding the plug ferrule while aligning the optical axis of the inserted plug ferrule with the optical axis of the optical fiber 2 inside the optical receptacle 100.

The sleeve 7 is a substantially cylindrical member having a slit (not shown). The other end portion of the ferrule 1 is inserted and fixed to one end side of the sleeve 7. Here, the sleeve 7 is provided apart from the case 8. Thereby, when inserting a plug ferrule in the sleeve 7, the outer diameter of the sleeve 7 can be expanded and it can be made easy to insert. The other end of the sleeve 7 is provided in contact with the holder 5. Thereby, the position shift of the axial direction of the sleeve 7 at the time of inserting a plug ferrule can be reduced.

  The sleeve 7 has a hollow portion on the other end side when the ferrule 1 is inserted and fixed. A plug ferrule is inserted into the hollow portion from the other end side. The sleeve 7 has slits that are formed from one end portion to the other end portion and open to the inner peripheral surface and the outer peripheral surface of the sleeve 7. Since the sleeve 7 has such a slit, when the plug ferrule is inserted and fixed, the sleeve 7 can be deformed to expand the inner diameter. Thereby, insertion of a plug ferrule can be performed easily. For example, the slit may have a width of 0.2 to 0.4 mm.

  As with the ferrule 1, the sleeve 7 is made of a simple substance such as zirconium oxide (zirconia), aluminum oxide (alumina), mullite, silicon nitride, silicon carbide, or aluminum nitride, ceramics containing these as main components, crystallized glass, or the like. Glass ceramics or the like can be used. Among them, it is preferable to use zirconia ceramics excellent in environmental resistance and toughness. Further, since the slits are provided, when the plug ferrule is inserted, these can be held by being appropriately elastically deformed. For example, if the outer diameter of the ferrule 1 and the plug ferrule to be inserted is 1.25 mm, the inner diameter of the sleeve 7 before the ferrule 1 and the plug ferrule are inserted may be set to 1.2 mm. By inserting the ferrule 1 and the plug ferrule into the sleeve 7, the inner diameter can be changed to, for example, 1.25 mm, and the ferrule 1 and the plug ferrule can be securely held by the sleeve 7. In this example, the sleeve 7 is provided with a slit, but a so-called precision sleeve having no slit may be used.

  The plug ferrule is a columnar member having a through hole penetrating from one end to the other end. An optical fiber is inserted into the through hole of the plug ferrule over the entire length of the plug ferrule. By abutting one end face of the plug ferrule against the other end face of the ferrule 1, the optical fiber 2 of the ferrule 1 and the optical fiber of the plug ferrule are optically connected.

  As with the ferrule 1 and the sleeve 7, the plug ferrule is, for example, a simple substance such as zirconium oxide (zirconia), aluminum oxide (alumina), mullite, silicon nitride, silicon carbide, or aluminum nitride, or a ceramic or crystal containing these as a main component. Glass ceramics such as vitrified glass can be used. Among them, it is preferable to use zirconia ceramics excellent in environmental resistance and toughness.

  The case 8 is a substantially cylindrical member, and is provided so as to surround the ferrule 1 so that the distal end portion of the other end side of the ferrule 1 and the sleeve 7 into which the ferrule 1 is inserted are in contact with the outside. It is provided to protect these so that there is no. The case 8 surrounds the ferrule 1 so that one end of the case 8 is press-fitted into the other end of the holder 5 and a gap exists between them. The size of the gap can be set to 0.15 mm to 0.3 mm, for example. The case 8 has a so-called flange-shaped extending portion 81 in which a part of the outer peripheral portion extends in the outer peripheral direction. As a material of the case 8, for example, a metal material such as stainless steel can be used.

According to the optical receptacle 100 of the present embodiment as described above, the possibility that the optical fiber 2 is damaged when the optical fiber 2 is inserted into the ferrule 1 is reduced. Damage can be reduced and optical signals can be transmitted with high reliability.

<Modification 1>
Modification 1 of the optical fiber holding component 10 and the optical fiber pigtail 101 will be described. In addition, in each structure of this example, about the member which has the structure and function similar to the above-mentioned optical fiber holding component 10 and the optical fiber pigtail 101, the same referential mark is attached | subjected and the detailed description is abbreviate | omitted.

  In the optical fiber holding component 10 shown in FIGS. 1 to 5, the first tapered portion 31 in the ferrule 1 and one end surface of the ferrule 1 are continuous, but the present invention is not limited to this. For example, as shown in FIGS. 6-8, the structure which the 1st taper part 31 and the one end surface of the ferrule 1 are not continuous may be sufficient.

  In the present modification, the through hole 11 further includes a covering member fixing portion 91 and a third taper portion 92 between the first taper portion 31 and one end surface of the ferrule 1.

  The covering member fixing portion 91 is an area for fixing the covering member 21 that covers the optical fiber 2. The covering member fixing portion 91 has an inner peripheral surface continuously provided on one end side of the first taper portion 31. The covering member fixing portion 91 has a constant inner diameter. The inner diameter of the covering member fixing portion 91 is set according to the outer diameter of the covering member 21 inserted into the covering member fixing portion 91. Specifically, the inner diameter of the covering member fixing portion 91 may be set larger than the outer diameter of the region of the covering member 21 that is inserted into the covering member 91. The inner diameter of the covering member fixing portion 91 may be set to, for example, 0.3 mm if the outer diameter of the region inserted into the ferrule 1 in the covering member 21 is 0.25 mm. In this case, the outer diameter of the end portion on the one end side of the first taper portion 31 is also set to 0.3 mm.

  In this modification, the through-hole 11 has the covering member fixing portion 91, so that the ferrule 1 can be held together with the covering member 21 when the optical fiber 2 is inserted into the ferrule 1. By holding the optical fiber 2 together with the covering member 21, the surface area of the target held by the ferrule 1 can be increased compared to the case where the ferrule 1 holds only the optical fiber 2. Thereby, the ferrule 1 and the optical fiber 2 can be more firmly fixed.

  Furthermore, if the covering member 21 is made of a resin material, the bondability between the resin member 21 and the adhesive 6 is better than the bondability between the optical fiber 1 and the adhesive 6. Thereby, the ferrule 1 and the optical fiber 2 can be fixed more firmly.

  The third taper portion 92 is a portion where the covering member 21 is inserted first, and opens at one end of the ferrule 1. The third taper portion 92 is a portion for roughly positioning the insertion position of the covering member 21. Furthermore, it is also a site | part with which the adhesive agent 6 for fixing the covering member 21 and the ferrule 1 is filled after inserting the covering member 21 in the covering member fixing | fixed part 91. FIG. The third tapered portion 92 has an inner peripheral surface that is inclined with respect to the through direction of the through hole 11 when viewed in a cross section in a cross section parallel to the through direction of the through hole 11. Specifically, the ferrule 1 has an inner peripheral surface that decreases in inner diameter from one end side toward the other end side. Therefore, since the third tapered portion 92 functions as a guide, the covering member 21 can be easily inserted into the covering member fixing portion 91 by inserting the covering member 21 into the third tapered portion 92.

  The inner diameter of the third taper portion 92 is preferably set to 1 mm, for example.

In this modification, the outer diameter of the region inserted into the ferrule 1 of the covering member 21 is small. Thereby, the covering member 21 can be inserted into the covering member fixing portion 91 without excessively increasing the inner diameter of the covering member fixing portion 91. Thereby, the covering member 21 can be inserted into the covering member 91 while maintaining the strength of the ferrule 1.

  As a method of reducing the outer diameter of the region inserted into the ferrule 1 in the covering member 21, the following method may be used. As a first example, there is a method in which the covering member 21 has a two-layer structure including an inner layer and an outer layer, and the outer layer is removed in the region inserted into the covering member fixing portion 91. As a second example, there is a method of reducing the outer diameter by cutting out the end of the covering member 21.

  In the present modification, the adhesive 6 is filled in the third taper portion 92 and the covering member fixing portion 91 so as to adhere the ferrule 1 and the covering member 21. The adhesive 6 is filled not only in the third taper portion 92, the covering member fixing portion 91 and the first taper portion 31 but also in the intermediate portion 32 so as to bond the ferrule 1 and the optical fiber 2. In this manner, the ferrule 1 and the optical fiber 2 can be firmly fixed by fixing the optical fiber 2 through the covering member 21 in the covering member fixing portion 91 and fixing the optical fiber 2 in the intermediate portion 32.

  In particular, since the intermediate portion 32 is provided and the adhesive 6 is filled, for example, compared to a case where the intermediate portion 32 is not provided and only the covering member fixing portion 91 is provided. However, the fixation between the ferrule 1 and the optical fiber 2 can be strengthened.

  As described above, when the optical fiber 2 is inserted into the ferrule 1, the intermediate portion 32 functions as a part for adjusting the insertion direction of the optical fiber 2, and light is inserted after the optical fiber 2 is inserted. The fiber 2 and the ferrule 1 can function as a part for strengthening the fixation.

  The configuration in which the intermediate portion 32 is filled with the adhesive 6 is not limited to the first modification. For example, this configuration may be adopted in the above-described embodiment.

1: Ferrule 2: Optical fiber 21: Cover member 11: Through hole 12: Chamfered portion 3: Optical fiber introduction portion 31: First taper portion 31a: First region 31b: Second region 32: Intermediate portion 33: Second taper Part 4: Optical fiber holding part 5: Holder 6: Adhesive 7: Sleeve 8: Case 81: Extension part 91: Cover member fixing part 92: Third taper part 10: Optical fiber holding part 100: Optical receptacle 101: Optical fiber pigtail a: first angle b: second angle

Claims (6)

A ferrule having a through hole in which an optical fiber is inserted and fixed from one end side,
The through hole has a first tapered portion whose inner diameter decreases from the one end side toward the other end side, and an inner peripheral surface provided continuously on the other end side of the first tapered portion, and has a constant inner diameter. And an intermediate portion continuously provided on the other end side of the intermediate portion, and a second taper portion whose inner diameter decreases from the one end side toward the other end side. Characteristic ferrule.   The ferrule according to claim 1, wherein a length of the intermediate portion is longer than a length of the first tapered portion.   2. The ferrule according to claim 1, wherein the through-hole further includes a covering member fixing portion having an inner diameter that is continuously provided on the one end side of the first taper portion. . The ferrule according to any one of claims 1 to 3,
An optical fiber holding component comprising: a holder that holds the ferrule so as to surround one end of the ferrule.   An optical fiber pigtail comprising: the optical fiber holding component according to claim 4; and an optical fiber inserted into and fixed to the ferrule.   An optical receptacle comprising: the optical fiber pigtail according to claim 5; and a sleeve provided at the other end of the ferrule into which a plug ferrule is inserted.

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