JP2009265601A - Multiple-fiber ferrule and method for manufacturing thereof - Google Patents

Abstract

The present invention provides a multi-core optical fiber ferrule that is excellent in positional accuracy and can be miniaturized.
An optical fiber support including a cylindrical body portion, a substrate portion, and a lid portion having a lower surface disposed on an upper surface of the substrate portion, and being inserted into an inner hole of the cylindrical body portion. The optical fiber support 2 includes a plurality of groove portions 7 into which the optical fibers are inserted in at least one of the upper surface of the substrate portion 5 and the lower surface of the lid portion 6.
[Selection] Figure 1

Description

  The present invention relates to a multi-core ferrule used for optical communication and the like, and relates to a multi-core ferrule having a coupling end face for holding a plurality of optical fibers and optically coupling with other optical fibers.

  Conventionally, a multi-core optical connector that optically couples optical fibers by bringing a plurality of optical fibers inserted and held in through holes of an optical fiber fixture having a multi-core ferrule into contact with each other at the coupling end surface of the multi-core ferrule is, for example, It is used for optical signal processing such as optical communication, and is used for a semiconductor laser module composed of a semiconductor laser and an optical fiber.

  As shown in FIG. 9, the multi-core optical connector is made of plastics such as epoxy resin, metal, or the like, and has an optical fiber fixture 32 having a plurality of through holes 33 in the center thereof, and a through hole of the optical fiber fixture 32 A multi-core optical fiber 34 is inserted and held in the hole 33 via an adhesive, and a guide pin with which two guide pins 38 are fitted to the coupling end surface 37 of the optical fiber fixture 32 having the opening of the through hole 33. A hole 35 is provided.

When connecting a pair of multi-core optical connectors, two guide pins 38 with very high dimensional accuracy are fitted into the two guide pin holes 35 for positioning, respectively. Is fitted into two guide pin holes 35 provided in the optical fiber fixture 32 of the other multi-core optical connector 31 to optically couple the optical fibers positioned with high accuracy.
JP-A-4-347806

  However, in the conventional optical fiber fixture 32, it is difficult to form the plurality of through holes 33 with high positional accuracy. Therefore, in the conventional multi-core optical connector, the multi-core optical fiber 34 is positioned by fitting two guide pins 38 into the two guide pin holes 35 when connecting a pair of multi-core optical connectors. . However, in such a configuration, the positional accuracy of each guide pin hole 35 may be reduced due to accumulation of manufacturing tolerances, and the connection loss of the multi-core optical fiber 34 may be deteriorated.

  In addition, the guide pin hole 35 and the guide pin 38 are required to have a very high processing accuracy, which increases the processing cost. On the other hand, the two guide pin holes 35 occupy the coupling end surface 37 of the optical fiber fixture 32. Therefore, it is difficult to reduce the size of the multi-core optical connector.

  The present invention has been made in view of the above problems, and an object thereof is to provide a multi-core ferrule that can be used for a multi-core optical connector that is excellent in positional accuracy and can be miniaturized.

  In view of the above problems, the multi-core ferrule according to the present invention includes a cylindrical body portion, a substrate portion, and a lid portion whose lower surface is disposed on the upper surface of the substrate portion. And an optical fiber support inserted into the optical fiber support, wherein the optical fiber support has a plurality of grooves into which optical fibers are inserted into at least one of the upper surface of the substrate portion and the lower surface of the lid portion. And

  In the multi-core ferrule of the present invention, preferably, the cylindrical body portion has a large diameter portion and a small diameter portion having different diameters of the inner hole, and the optical fiber support is formed on the large diameter portion. The one end portion of the optical fiber support is in contact with a step portion constituted by the large diameter portion and the small diameter portion.

  In the multi-core ferrule of the present invention, the cylindrical body portion and the optical fiber support preferably include the same material.

  In the multi-core ferrule of the present invention, the cylindrical body part and the optical fiber support are preferably made of ceramics.

  Further, in the multi-core ferrule of the present invention, the inner hole of the cylindrical portion has a concave curved surface in which the side surface adjacent to the lower surface of the substrate portion or the upper surface of the lid portion does not contact the side surface of the substrate portion or the lid portion. Has been.

  The method for manufacturing a multi-core ferrule according to the present invention is a method for manufacturing a ferrule in which an optical fiber support including a substrate portion and a lid portion is inserted into an inner hole of a cylindrical body portion, and the substrate portion And a step of preparing the lid portion, a step of forming a plurality of groove portions on at least one of the upper surface of the substrate portion and the lower surface of the lid portion, and bonding the upper surface of the substrate portion and the lower surface of the lid portion, A step of forming an optical fiber support, a step of inserting the optical fiber support into an inner hole of a cylindrical ceramic molded body serving as a precursor of the cylindrical body portion, and firing the ceramic molded body And a process.

  In the method for manufacturing a multi-core ferrule according to the present invention, preferably, the substrate portion and the lid portion are formed of a sintered body containing the same material as the ceramic constituting the cylindrical body portion.

  According to the multi-core ferrule of the present invention, since the optical fiber support having a groove portion formed in advance with high accuracy can be arranged in the cylindrical body portion, the positional accuracy of the groove portion can be improved. As a result, in the present invention, even if the optical fiber is arranged in the groove portion of the optical fiber support and the optical connector is assembled, the positional accuracy of the optical fiber can be improved, so that the connection loss of the optical fiber can be reduced. it can. Furthermore, in the multi-core ferrule of the present invention, since the groove portion is positioned with high accuracy, a positioning pin is not required, which can contribute to miniaturization of parts.

  Therefore, according to the present invention, it is possible to provide a multi-core optical fiber ferrule that has excellent positional accuracy and can be miniaturized.

  Hereinafter, the multi-core ferrule according to the present invention will be described in detail with reference to the drawings. The following embodiments are illustrative of the present invention and are not limiting. In addition, in each figure, the same code | symbol is attached | subjected about the common member and the overlapping description is abbreviate | omitted.

(Embodiment 1)
FIG. 1 is a perspective view of a multicore ferrule 1 according to Embodiment 1 of the present invention, and FIG. 2 is a perspective view of an optical fiber support portion 2 constituting the multicore ferrule 1. FIG. 1 shows a state where the optical fiber 8 is inserted into the multi-core ferrule 1. As shown in FIG. 1, the multi-core ferrule 1 according to the present embodiment includes a cylindrical body portion 4 provided with an inner hole 3 near the center, and an optical fiber support portion 2 inserted into the inner hole 3. As shown in FIG. 2, the optical fiber support portion 2 includes a substrate portion 5 and a lid portion 6, and the upper surface of the substrate portion 5 faces the lower surface of the lid portion 6. A plurality of groove portions 7 for inserting and fixing the optical fiber 8 are formed on the upper surface of the substrate portion 5 along the position where the optical fiber 8 is disposed, for example, along the longitudinal direction of the cylindrical body portion 4. The upper surface of the substrate portion 5 is bonded to the lower surface of the lid portion 6, and the groove portion 7 is formed near the boundary between the substrate portion 5 and the lid portion 6.

  The groove part 7 may be formed in the substrate part 5, may be formed in the lid part 6, or may be formed in both of them. In any case, it is important that the groove portion 7 is provided on the upper surface of the substrate portion 5 or the lower surface of the lid portion 6, and the groove portion 7 is disposed in the vicinity of the boundary when the substrate portion 5 and the lid portion 6 are bonded together. is there.

  FIG. 3 is a cross-sectional view taken along a cross-section AA of the cylindrical body portion 4 constituting the multicore ferrule 1. As shown in FIG. 3, the cylindrical body portion 4 has an inner hole 3 for inserting the optical fiber support portion 2 at the center. The inner hole 3 has a large diameter portion 10 and a small diameter portion 11 having different diameters. Then, as shown in FIG. 4, the optical fiber support 2 is inserted into the large-diameter portion 10, and the one end portion 12 of the optical fiber support 2 changes in diameter between the large-diameter portion 10 and the small-diameter portion 11. Is in contact with the stepped portion 13 formed by the boundary portion. On the other hand, when an optical fiber (not shown) is inserted into the multi-core ferrule 1, a part of the optical fiber covering portion extending from the optical fiber support 2 is accommodated in the small diameter portion 11 of the cylindrical portion 4. ing. Therefore, the clearance between the multi-core ferrule 1 and the optical fiber covering portion can be reduced, which is advantageous in that the optical fiber is stably fixed.

  The length of the large diameter portion 10 and the small diameter portion 11 in the axial direction of the cylindrical portion 4 (longitudinal direction of the cylindrical portion 4) is the same as the length of the small diameter portion 11 in the axial direction of the cylindrical portion 4. Longer than the length of the part 10 is preferable. As compared with the small diameter portion 11, the optical fiber support 2 disposed in the large diameter portion 10 can be made small by reducing the formation region of the large diameter portion 10. Therefore, according to such an embodiment, the length of the optical fiber portion disposed on the optical fiber support portion 2 from which the coating has been removed can be shortened, and the optical fiber coating in which the optical fiber is covered with a resin or the like The area | region fixed by the small diameter part 11 of a part can be increased. Therefore, with such a configuration, the mechanical strength is weaker than that of the optical fiber coating portion, and the length of the optical fiber portion from which the coating has been removed can be shortened, thereby reducing the strength deterioration of the optical fiber. be able to.

  The shape of the large-diameter portion 10 of the inner hole 3 of the tubular body portion 4 may be any shape as long as the optical fiber support 2 can be inserted, and examples thereof include a circular shape and a polygonal shape such as a rectangle. .

  In addition, as shown in FIG. 5, the side surface 3b of the inner hole 3 does not contact the lower surface 5a of the substrate unit 5 or the upper surface 6a of the cover unit 6 and does not contact the side surfaces 5b and 6b of the substrate unit 5 or the cover unit 6. A curved surface is more preferable. For example, when the inner hole 3 is a rectangle (rectangular shape) shown in FIG. 1, when the cylindrical body portion 4 is fired, the long side direction of the inner hole 3 is longer than the short side direction, and thus the long side direction firing is performed. The amount of shrinkage is greater. Due to the difference in firing shrinkage, the contraction strain in the long side direction of the optical fiber support 2 becomes larger than the contraction strain in the short side direction, so that the inner hole 3 is distorted, causing deformation and warping, cracks, etc. May increase the possibility of entering. However, since the side surface 3b is a concave curved surface and is not in contact with the side surfaces 5b and 6b of the optical fiber support 2, the space between the optical fiber support 2 and the side 3b of the inner hole 3 is long. Distortion due to firing shrinkage in the side direction is alleviated. Accordingly, warpage and cracks due to strain generated in the inner hole 3 during firing can be reduced. Therefore, the optical fiber support 2 can be fixed with higher accuracy.

  In FIG. 5, the side surface 3b is formed as a semicircular concave curved surface, but the present invention is not limited to this, and it is sufficient that the side surface 3b is a concave curved surface that does not contact the side surfaces 5b and 6b. For example, the concave curved surface may be a polygonal shape with rounded corners such as a curved surface arranged at the apex of a triangle, other polygonal shapes, or the like.

  Further, a chamfered portion (not shown) such as a C-plane or R-plane shape may be provided on the boundary surface between the large-diameter portion 10 and the small-diameter portion 11 from the viewpoint of reducing stress concentration. In the present embodiment, the large-diameter portion 10 and the small-diameter portion 11 having different diameters are formed in the cylindrical portion 4, but the present invention is not limited to such a form, and the inner hole 3 The diameter may be constant.

  As shown in FIG. 2, the substrate portion 5 constituting the optical fiber support 2 has a plurality of groove portions 7 formed on the substrate portion 5 along one direction. Examples of the shape of the groove portion 7 include a round groove, a U-groove, and the like, but in order to fix the optical fiber with high accuracy, a V-groove shape that is hardly affected by the accuracy of the groove shape is most preferable.

  The lid portion 6, which is the other member constituting the optical fiber support 2, has a flat surface processed with high precision, and the optical fiber inserted into the groove portion 7 of the substrate portion 5 can be obtained by this flat surface portion. It can be pressed and fixed. Further, the lid 6 is not a plane processed with high accuracy, and even if it has a plurality of grooves 7 formed in one direction like the substrate 5, the purpose of fixing the optical fiber can be achieved.

The cylindrical portion 4 is formed, for example, in a cylindrical shape or a rectangular parallelepiped shape, and has an inner hole (through hole) 3 for holding the optical fiber support in the longitudinal direction. Examples of the material constituting the cylindrical body portion 4 include zirconium oxide (zirconia), aluminum oxide (alumina), mullite, silicon nitride, silicon carbide, and aluminum nitride alone, ceramics containing these as main components, crystallized glass, and the like. Examples include glass ceramics, phosphor bronze, beryllium copper, brass, stainless steel, and plastics such as epoxy and liquid crystal polymer. Among them, zirconia-based ceramics (ceramics based on zirconia) with excellent weather resistance and toughness Is preferred. Among zirconia-based ceramics, in particular, at least one selected from the group consisting of zirconium oxide (ZrO ₂ ) as a main component and Y ₂ O ₃ , CaO, MgO, CeO ₂ , Dy ₂ O _{3 and the} like is used as a stabilizer. Partially stabilized zirconia ceramics (mainly tetragonal crystals) are more preferable from the viewpoints of wear resistance and elastic deformation.

  Further, the substrate portion 5 and the lid portion 6 constituting the optical fiber support 2 can also be selected from the same material group as that of the cylindrical portion 4 and used. However, when a multi-core optical connector is manufactured by fixing the optical fiber 8 to the multi-core ferrule 1 in which the optical fiber support 2 is fixed to the inner hole 3 of the cylindrical portion 4, the optical fiber support 2 and the cylindrical body are produced. The part 4 is preferably made of the same material. This is because the multi-core ferrule 1 is often mirror-polished on the end face on the optical coupling side, so that there is a difference in the amount of polishing between the cylindrical portion 4 and the optical fiber support 2, which reduces the level difference. Because it can be done.

Further, among the ceramics as described above, the cylindrical portion 4 and the optical fiber support 2 are mainly composed of zirconium oxide (ZrO ₂ ), and Y ₂ O ₃ , CaO, MgO, CeO ₂ , Dy ₂ O _3. It is preferable in that it is composed of partially stabilized zirconia ceramics (mainly tetragonal crystals) containing at least one selected from the group consisting of the above as a stabilizer. The substrate portion 5 and the lid portion 6 constituting the optical fiber support 2 may be fixed to the inner hole 3 of the cylindrical portion 4 with an adhesive such as epoxy resin or acrylic resin.

  Hereinafter, the production method of the multi-core ferrule 1 according to the present invention will be described in detail. Here, although the case where the optical fiber support 2 and the cylindrical part 4 are formed of ceramics will be described, the present invention is not limited to ceramics.

  First, a molded body of the substrate portion 5 and the lid portion 6 constituting the optical fiber support 2 is formed by a predetermined molding method such as injection molding, press molding, extrusion molding, etc., from a ceramic raw material obtained by kneading zirconia ceramic powder and a binder. Make it. The optical fiber support 2 may be formed in a cylindrical shape or a rectangular parallelepiped shape. And the obtained molded object is baked at 1300-1500 degreeC, and it is set as a sintered compact. Next, the sintered body is subjected to cutting or polishing so as to have a predetermined outer shape, and is subjected to grinding using a milling machine or an NC processing machine to form a predetermined groove 7 shape, for example, a V groove. . In addition, a predetermined shape may be formed in advance on the molded body before firing by cutting or the like, or a predetermined groove 7 shape, for example, a V-groove is formed by performing grinding or the like, and then Firing may be performed.

  Next, a mixture obtained by kneading a zirconia ceramic powder and a binder is produced by a predetermined molding method such as injection molding, press molding, extrusion molding, or the like. The molded body serving as the precursor of the cylindrical body portion 4 may be cylindrical or rectangular as long as it has the inner hole 3 corresponding to the outer shape of the optical fiber support portion 2. Thereafter, the substrate portion 5 and the lid portion 6 constituting the above-mentioned fired and processed optical fiber support 2 are inserted into the inner hole 3 of the obtained molded body. At this time, if the substrate portion 5 and the lid portion 6 constituting the optical fiber support 2 are temporarily fixed with an adhesive such as an epoxy resin or an acrylic resin, the substrate portion 5 and the lid portion 6 can be accurately positioned.

  And the molded object of the obtained cylinder part 4 is baked at 1300-1500 degreeC in the state which the optical fiber support body 2 inserted in the inner hole 3. FIG. Since the molded body of the cylindrical portion 4 is baked and shrunk, the inner hole 3 is also shrunk in the direction of decreasing the diameter, and the optical fiber support 2 inserted into the inner hole 3 can be firmly fixed. Thereafter, the outer shape is cut or polished to a predetermined size to obtain a predetermined shape, thereby forming a multi-core ferrule 1.

  Moreover, when forming the cylindrical part 4 which has the large diameter part 10 and the small diameter part 11, it can produce by baking what was processed into the diameter of a predetermined magnitude | size at the time of shaping | molding. On the other hand, if the optical fiber support 2 shorter than the length of the cylindrical portion 4 in the longitudinal direction is inserted into the inner hole 3 and the cylindrical body 4 is fired, the inside of the portion where the optical fiber support 2 is not disposed. Since the diameter of the hole 3 is smaller than the portion where the optical fiber support 2 is disposed, the cylindrical portion 4 having a different diameter can be produced even by such a method.

  By the above manufacturing method, the multi-core ferrule 1 of the present invention can easily fix the substrate part 5 and the lid part 6 post-processed with high accuracy to the cylindrical body part 4, so that the inexpensive and high-precision multi-core ferrule 1 can be obtained. Can be realized.

  In addition, the production method of the multi-core ferrule 1 of the present invention is not limited to this, for example, a method in which the optical fiber support 2 is press-fitted or bonded and fixed to the inner hole 3 of the fired cylindrical body portion 4. Also mentioned.

(Embodiment 2)
The multi-core ferrule 101 according to the second embodiment of the invention is different from the multi-core ferrule 1 according to the first embodiment in the structure of the optical fiber support. Other configurations are the same as those of the multi-core ferrule 1 according to the first embodiment.

  6 and 7 are perspective views of the optical fiber support 102 according to the second embodiment. In the optical fiber support 102 of the multi-core ferrule 101 according to the second embodiment, the lid portion 106 is formed shorter than the substrate portion 105 in the longitudinal direction (formation direction of the groove 107), and the upper surface of the substrate portion 105 Is formed with a raised portion 120 that substantially matches the length of the lid portion 106 in the longitudinal direction. In this embodiment, a groove 107 is formed in the raised portion 120 of the substrate portion 105. Then, if the height difference between the bottom of the groove 107 and the top surface of the substrate part 105 other than the raised part 120 is made substantially the same as the thickness of the resin covering the optical fiber, Since it can arrange | position on a substantially identical plane, without bending, the bending stress which acts on an optical fiber can be reduced.

  FIG. 8 is a cross-sectional view of the multi-core ferrule 101 in which the optical fiber support 102 of the multi-core ferrule 101 according to the second embodiment is inserted. As shown in FIG. 8, since the lid portion 106 is formed shorter than the substrate portion 105 in the longitudinal direction, the lid portion 106 is disposed when the optical fiber support portion 102 is disposed in the inner hole of the cylindrical body portion 104. A gap 130 is formed between the upper surface of the non-substrate portion 105 and the inner peripheral surface of the cylindrical body 104. Therefore, according to such a form, when the optical fiber support portion 102 is inserted into the cylindrical body portion 104 made of ceramics and fired, strain generated by firing shrinkage escapes to the gap portion 130, and thus the tubular portion 104. The warp that occurs can be reduced. Further, the thickness of the contracted portion of the cylindrical portion 104 that has escaped into the gap 130 increases toward the center, and the locking portion 121 is formed on the lid portion 106 by the increase in the thickness. Since the locking portion 121 can suppress the movement of the optical fiber support 102 in the axial direction of the cylindrical body portion 104, the positional deviation of the optical fiber support 102 can be reduced.

  Therefore, in the second embodiment, it is possible to realize a ferrule that is more accurate and more durable than the ferrule according to the first embodiment.

FIG. 1 is a perspective view of a multi-core ferrule according to Embodiment 1 of the present invention. FIG. 2 is a perspective view of the optical fiber support according to Embodiment 1 of the present invention. FIG. 3 is a cross-sectional view of the cylindrical body portion according to Embodiment 1 of the present invention. FIG. 4 is a cross-sectional view of the multi-core ferrule according to Embodiment 1 of the present invention. FIG. 5 is a perspective view of a multi-core ferrule showing another embodiment according to Embodiment 1 of the present invention. FIG. 6 is a perspective view of an optical fiber support according to Embodiment 2 of the present invention. FIG. 7 is a perspective view of an optical fiber support according to Embodiment 2 of the present invention in which an optical fiber is inserted. FIG. 8 is a cross-sectional view of a multi-core ferrule according to Embodiment 2 of the present invention. FIG. 9 is a perspective view of a conventional multi-core ferrule.

Explanation of symbols

1,101: Multi-core ferrule,
2,102: optical fiber support,
3: Inner hole,
4,104: cylinder part,
5, 105: substrate portion,
6,106: lid part,
7: groove
8: Optical fiber
10: Large diameter part,
11: Small diameter part,
12: one end,
13: Stepped part,
120: protuberance,
121: locking part,
130: gap

Claims (7)

A cylinder part;
An optical fiber support inserted into the inner hole of the cylindrical portion, the substrate portion and a lower surface including a lid portion disposed on the upper surface of the substrate portion,
The optical fiber support has a plurality of groove portions into which optical fibers are inserted in at least one of the upper surface of the substrate portion and the lower surface of the lid portion. The cylindrical body portion has a large diameter portion and a small diameter portion having different diameters of the inner hole, the optical fiber support is inserted into the large diameter portion, and one end of the optical fiber support The multi-core ferrule according to claim 1, wherein a portion is in contact with a stepped portion constituted by the large diameter portion and the small diameter portion. The multi-core ferrule according to claim 1 or 2, wherein the cylindrical portion and the optical fiber support include the same material. The multi-core ferrule according to claim 3, wherein the cylindrical body part and the optical fiber support are made of ceramics. The inner hole of the cylindrical body portion is a concave curved surface in which a side surface adjacent to a lower surface of the substrate portion or an upper surface of the lid portion is not in contact with a side surface of the substrate portion or the lid portion. Item 5. The multi-core ferrule according to any one of Items 1 to 4. A method of manufacturing a multi-core ferrule in which an optical fiber support including a substrate part and a cover part is inserted into an inner hole of a cylindrical part,
Preparing the substrate portion and the lid portion;
Forming a plurality of grooves in at least one of the upper surface of the substrate portion and the lower surface of the lid portion;
Bonding the upper surface of the substrate portion and the lower surface of the lid portion to form an optical fiber support;
The step of inserting the optical fiber support into the inner hole of the cylindrical ceramic molded body that becomes the precursor of the cylindrical body part;
And a step of firing the ceramic molded body. The method for producing a multi-core ferrule, wherein the substrate portion and the lid portion are formed of a sintered body containing the same material as the ceramics constituting the cylindrical body portion.

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