JP5117471B2 - Bending connector structure - Google Patents

Description

  The present invention relates to a bent connector structure.

  Conventionally, an optical fiber component in which an optical fiber is positioned and fixed to a fixing member such as a ferrule is known. In this optical fiber component, a method of converting the light guiding direction by about 90 degrees has been studied from the demand for miniaturization and the like.

  In Patent Document 1 below, an optical fiber in which a bent portion is formed by bending in a curved shape with a predetermined bending radius is accommodated in a space portion of a fixing member such as a ferrule, and around the bent portion of the optical fiber from a clad portion. A structure filled with a resin having a small refractive index is disclosed.

JP 2008-152229 A

  However, in the said patent document 1, it receives to the influence of resin with which the optical characteristic of the optical fiber component was filled. That is, there is a problem that the refractive index of the resin is likely to fluctuate depending on the environmental temperature, and when the refractive index fluctuates, light leakage occurs and the optical characteristics of the optical fiber component are affected.

  In view of the above facts, an object of the present invention is to obtain a bent connector structure capable of suppressing fluctuations in optical characteristics due to environmental temperature.

In order to achieve the above object, a bent connector structure according to the invention of claim 1 includes an optical fiber in which a bent portion is formed and a first fixed portion in which one side of the bent portion of the optical fiber is inserted and fixed. A ferrule including: a hollow portion in which the bent portion is housed; and a second fixing portion in which a tip portion of the optical fiber on the other side of the bent portion is inserted and fixed. lid bends in a non-contact with the wall surface of the cavity, and the cavity are an enclosed space, said ferrule to a ferrule body, wherein the cavity is formed, the sealed space covering the cavity The ferrule main body and the lid member are each provided with a recess that widens the wall surface of the cavity from the second fixed portion to the bent portion .

According to the present invention, one side of the bent portion of the optical fiber is inserted and fixed to the first fixing portion of the ferrule, and the other end portion of the bent portion of the optical fiber is inserted and fixed to the second fixing portion of the ferrule. Has been. The bent part of the optical fiber is not in contact with the wall surface of the cavity part of the ferrule, and the cavity part is a sealed space, and the optical waveguide direction is changed by the difference in refractive index between the bent part of the optical fiber and the gas in the sealed space. And bending loss is reduced. In this configuration, it is possible to prevent the optical characteristics of the bending connector from fluctuating due to the environmental temperature by enclosing a gas whose refractive index is difficult to change due to a temperature change.
In addition, after storing the bent portion of the optical fiber in the hollow portion formed in the ferrule body, the hollow portion is covered with a lid member, and the optical fiber is fixed to the first fixing portion and the second fixing portion of the ferrule. The part is a sealed space. This facilitates the assembly of the optical fiber to the ferrule.
Further, the ferrule main body and the lid member are provided with a hollow portion that widens the wall surface of the hollow portion from the second fixing portion to the bending portion. For example, the tip portion of the optical fiber is fixed to the ferrule main body with an adhesive. In some cases, the indented portion becomes an escape portion through which the adhesive flows, and the adhesive can be prevented from adhering to the bent portion of the optical fiber.

  In order to achieve the above object, the bent connector structure according to the invention of claim 2 is the invention according to claim 1, wherein the bent portion is formed by bending a bare optical fiber excluding the coating of the optical fiber. Is formed.

  According to a third aspect of the present invention, in the bent connector structure according to the first or second aspect, air or an inert gas is sealed in the sealed space.

  According to the present invention, air or an inert gas is sealed in a sealed space around the bent portion. By sealing air or an inert gas having a lower refractive index than that of a conventional resin, optical characteristics are improved. The fluctuation can be more reliably suppressed.

According to a fourth aspect of the present invention, there is provided the bent connector structure according to any one of the first to third aspects, wherein the ferrule body constitutes the second fixing portion and the tip of the optical fiber. A groove part into which the part fits is formed.

  According to the present invention, by fitting the distal end portion of the optical fiber into the groove portion formed in the second fixing portion of the ferrule body, the distal end portion of the optical fiber can be positioned and the optical fiber can be prevented from being misaligned.

The bent connector structure according to the invention of claim 5 is the invention according to any one of claims 1 to 4 , wherein the tip end portion of the optical fiber is made of an epoxy resin adhesive on the second fixing portion. The optical fiber is bonded and fixed to the first fixing portion with a high-viscosity adhesive having a higher viscosity than the epoxy resin-based adhesive.

  According to the present invention, the distal end portion of the optical fiber is bonded and fixed to the second fixing portion with the epoxy resin adhesive, and the base side portion of the optical fiber is higher in viscosity than the epoxy resin adhesive to the first fixing portion. The optical fiber can be firmly fixed by holding at least two points on both sides of the bent portion. In addition, since the optical fiber is bonded and fixed to the first fixing portion with a high-viscosity adhesive, the adhesive does not flow into the vicinity of the bent portion of the optical fiber in the connector cavity, so that the optical fiber is securely attached to the first fixing portion. Can be fixed.

The bent connector structure according to the invention of claim 6 is the invention according to any one of claims 1 to 5 , wherein the tip of the optical fiber is formed on the surface of the ferrule on the second fixing portion side. A polished surface is also provided.

  According to the present invention, the surface of the ferrule on the second fixed portion side is provided with the polished surface polished together with the tip portion of the optical fiber, so that optical connection is possible.

A bent connector structure according to a seventh aspect of the present invention is the invention according to any one of the first to fifth aspects, wherein the second fixing portion of the ferrule has a holding hole for the optical fiber. An attachment is attached.

  According to the present invention, an attachment having an optical fiber holding hole is attached to the second fixing portion of the ferrule, and the optical fiber is inserted into and held in the holding hole formed with high accuracy, so that the optical fiber The position accuracy of the is improved.

According to an eighth aspect of the present invention, in the bent connector structure according to the seventh aspect of the present invention, an attachment-side polished surface polished with the optical fiber is provided on the surface of the attachment.

  According to the present invention, the attachment-side polished surface polished together with the optical fiber is provided on the surface of the attachment, and optical connection is possible.

A bent connector structure according to an invention of claim 9 is the invention according to any one of claims 1 to 8 , wherein the bent portion has a curvature of r = 0.5 to 3 mm. It has been done.

  According to the present invention, the optical loss can be reduced by arranging the optical fiber having a curvature of r = 0.5 to 3 mm in the sealed space.

According to a tenth aspect of the present invention, in the bent connector structure according to any one of the first to ninth aspects, the optical fiber is a tape-shaped optical fiber in which a plurality of optical fibers are arranged. There is something.

  According to the present invention, it is possible to improve the work efficiency when fixing a plurality of optical fibers, and it is possible to strengthen the adhesive fixing at the first fixing portion.

The bent connector structure according to the invention of claim 11 is the invention according to claim 5 , wherein the viscosity of the high viscosity adhesive is 50 to 300 Pa · s.

  According to the present invention, the viscosity of the high-viscosity adhesive is 50 to 300 Pa · s, and it is possible to prevent the adhesive from flowing into the bent portion when the first fixing portion of the ferrule is sealed.

The bent connector structure according to the invention of claim 12 is the invention according to any one of claims 1 to 11 , wherein the first fixing portion of the ferrule covers the optical fiber, and A flexible protective member having a tapered surface whose diameter increases toward the ferrule is attached to the inner surface.

  According to the present invention, the flexible protective member that covers the optical fiber is attached to the first fixing portion of the ferrule, and the occurrence of damage such as bending of the optical fiber is suppressed by the protective member. Moreover, the taper surface which diameter-expands toward a ferrule is formed in the inner surface of a protection member, and adhesive agents, such as a high-viscosity adhesive agent, will flow easily into the clearance gap between a protection member and an optical fiber.

According to a thirteenth aspect of the present invention, in the bent connector structure according to the twelfth aspect of the present invention, the protection member is formed of a soft rubber or a plastic made of an elastomer.

  According to the present invention, the protective member is formed of a plastic made of soft rubber or elastomer, and can more reliably prevent damage to the optical fiber.

A bent connector structure according to an invention of claim 14 is the invention according to any one of claims 1 to 13 , wherein the bent portion is bent by heat.

  According to the present invention, the bending portion is bent by heat, and the occurrence of bending strain can be prevented.

The bent connector structure according to the invention of claim 15 is the invention according to any one of claims 1 to 14 , wherein the optical axis of the optical fiber is bent by 90 to 150 degrees by the ferrule. Is.

  According to the present invention, the optical axis of the optical fiber is bent by 90 to 150 degrees by the ferrule, and the height of the connector in the optical axis direction of the optical component to be connected can be designed low.

A bending connector structure according to a sixteenth aspect of the present invention is the bending connector structure according to the fourth aspect , wherein the groove portions are arranged at a pitch of 250 μm or 125 μm.

  According to the present invention, by inserting a plurality of optical fibers into the groove portions, the plurality of optical fibers can be arranged close to each other and positioned with high accuracy.

  According to this invention, it can suppress that the optical characteristic of a bending connector changes with environmental temperature.

It is a perspective view which shows the whole structure by the side of the cover member of the bending connector structure which concerns on 1st Embodiment of this invention. It is a perspective view which shows the whole structure on the opposite side to the cover member of the bending connector structure which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the ferrule main body and lid member which are used for the bending connector structure which concerns on 1st Embodiment of this invention. It is a bending connector structure concerning a 2nd embodiment of the present invention, and is a perspective view showing the state where an attachment was connected to a ferrule main part and a lid member. It is sectional drawing which shows the state in which the attachment was connected to the ferrule main body and the cover member. It is a disassembled perspective view which shows the attachment connected to a ferrule main body and a cover member. It is a block diagram which shows the example of mounting on the board | substrate of the bending connector structure which concerns on 3rd Embodiment of this invention.

  Hereinafter, a first embodiment of the bending connector structure of the present invention will be described with reference to FIGS.

  FIG. 1 is a perspective view showing the overall configuration of the front side (lid member side) of the ferrule 14 of the bent connector structure 10, and FIG. 2 shows the overall configuration of the back side of the ferrule 14 of the bent connector structure 10. It is shown in a perspective view. FIG. 3 shows a cross-sectional view of the bent connector structure 10. As shown in these drawings, the bent connector structure 10 has a tape-shaped multi-core optical fiber 12 having a plurality of bare optical fibers 32 formed with bent portions 32A, and the tape-shaped multi-core optical fiber 12 fixed thereto. And a ferrule 14. The ferrule 14 includes a box-shaped ferrule main body 16 in which a concave portion 16A in which the bent portion 32A of the tape-shaped multi-core optical fiber 12 is accommodated, and a lid member 18 that covers the concave portion 16A of the ferrule main body 16. .

  A rectangular boot 20 as a protective member for protecting the tape-shaped multi-core optical fiber 12 is connected to one end in the longitudinal direction of the ferrule 14 (the end opposite to the tip 32B of the plurality of bare optical fibers 32). ing. In FIG. 3, the state which has arrange | positioned the cover member 18 of the bending connector structure 10 to the downward side is shown.

  The tape-shaped multi-core optical fiber 12 includes a plurality of bare optical fibers 32 and a tape-shaped covering portion 33 that covers the periphery of the bare optical fibers 32. The bare optical fiber 32 includes a core part and a cladding around the core part. The bare optical fiber 32 is formed with a bent portion 32A that is bent in a curved shape with a predetermined bending radius. For example, by heating the heating target portion of the bare optical fiber 32 at a temperature in the range of the softening point or more and the melting point or less by arc discharge, the heating target portion of the bare optical fiber 32 shifts to a state where bending can be performed, Bending portion 32A is formed by bending this heating target portion in a curved shape with a predetermined bending radius R, and the shape of bending portion 32A is fixed by cooling. The bending radius R is set so as to allow the light leakage. In this embodiment, the bare optical fiber 32 is bent in a curved shape so that the base side (the covering portion 33 side) of the bent portion 32A and the linear tip portion 32B on the tip side of the bent portion 32A are about 90 degrees. ing.

  In the ferrule body 16, a substantially rectangular cavity portion S is formed in a recess 16 </ b> A surrounded by the side wall 24 and the bottom surface portion 22 when viewed from the direction perpendicular to the plane of FIG. 3. The side wall 24 on the boot 20 side of the ferrule body 16 is provided with a concave insertion portion 24A as a first fixing portion through which the covering portion 33 of the tape-shaped multi-core optical fiber 12 is inserted and fixed. The bent portion 32A is housed in the concave portion 16A in a state where the covering portion 33 of the tape-shaped multi-core optical fiber 12 is inserted into the insertion portion 24A of the ferrule body 16.

  A plurality of grooves 26 into which the end portions 32B of the bare optical fibers 32 are fitted in the side wall 24 on the opposite side of the boot 20 of the ferrule body 16 along the vertical direction in FIG. Is formed. The position where the plurality of groove portions 26 of the ferrule body 16 are formed is the second fixing portion. The groove portion 26 has a substantially V-shaped cross section along the longitudinal direction of the ferrule body 16 (see FIG. 1). The plurality of groove portions 26 are arranged at a pitch of, for example, 250 μm, and the leading end portion 32 </ b> B of the bare optical fiber 32 is fitted into the groove portion 26. Note that the plurality of groove portions 26 may be arranged at a pitch of 125 μm according to the thickness of the bare optical fiber 32.

  At the position adjacent to the groove portion 26 of the side wall 24 of the ferrule body 16 (upper side shown in FIG. 3), the wall surface of the concave portion 16A is provided from the groove portion 26 to the portion facing the outer peripheral side of the bent portion 32A of the bare optical fiber 32. A recessed portion 28 is provided to expand with respect to the bent portion 32A. In the present embodiment, the recess portion 28 includes a tapered surface 28A inclined at an angle of about 45 degrees with respect to the surface on which the groove portion 26 is formed, and is formed at an angle of about 45 degrees from the end of the tapered surface 28A. It has a wall surface arranged along the vertical direction inside. When the tip portion 32B of the bare optical fiber 32 is bonded and fixed to the groove portion 26 and the lid member 18 with an adhesive 38 for bonding the tip portion 32B, the concave portion 28 is bent along the wall surface by the adhesive 38. It is an escape part for not flowing in.

  The lid member 18 is formed so that the outer shape of the lid member 18 is slightly smaller than the inner shape of the recess 16A so as to be fitted into the recess 16A of the ferrule body 16. The inner wall in the width direction of the recess 16A of the ferrule body 16 has a narrow width on the groove 26 side and a wide width on the boot 20 side (see FIG. 1). The lid member 18 has a first fitting portion 18A having a narrow lateral width that fits into the inner wall of the recess 16A of the ferrule body 16 on the groove 26 side, and a lateral width that fits the inner wall of the recess 16A of the ferrule body 16 on the boot 20 side. And a wide second fitting portion 18B. With the lid member 18 fitted in the recess 16A of the ferrule body 16, the end portions 32B of the plurality of bare optical fibers 32 of the tape-shaped multi-core optical fiber 12 are respectively inserted into the plurality of grooves 26 of the ferrule body 16 and the lid member 18 The end face 18C is pressed. Further, when the lid member 18 is fitted inside the recess 16A, a step for positioning in the depth direction may be provided to determine the insertion depth of the lid member 18.

  A notch 18D to which the boot 20 is connected is provided at the longitudinal end of the lid member 18 (see FIG. 3). On the inner wall surface of the lid member 18, an inclined surface 18E is formed at a position facing the inner peripheral side of the bent portion 32A of the bare optical fiber 32. The inclined surface 18E is formed at a position adjacent to the end surface 18C facing the groove 26 of the ferrule body 16, and is formed at an angle of about 45 degrees with respect to the end surface 18C. Due to the inclination of the end face 18C, the adhesive 38 for adhering the distal end portion 32B is prevented from adhering to the optical fiber along the wall surface.

  In the present embodiment, the ferrule body 16 and the lid member 18 are formed of a resin generally used for manufacturing a connector, particularly a PPS resin (polyphenylene sulfide resin) or an epoxy resin.

  The boot 20 includes a through-hole 20A through which the covering portion 33 of the tape-shaped multi-core optical fiber 12 is passed. The boot 20 is made of soft rubber or resin, and can be elastically deformed in the thickness direction of the covering portion 33 (up and down direction of the boot 20). A protrusion 20 </ b> B that protrudes toward the ferrule body 16 is formed on the periphery of one end of the boot 20. The boot 20 is connected to the ferrule body 16 and the lid member 18 by the projection 20B of the boot 20 being extrapolated around the side wall 24 of the ferrule body 16 and the notch 18D of the lid member 18.

  On one surface in the width direction of the through-hole 20A of the boot 20 (the surface on the lower side in FIG. 3), a tapered surface 20C is formed so that the vertical interval of the through-hole 20A gradually increases toward the ferrule body 16. Is formed. The covering portion 33 of the tape-shaped multi-core optical fiber 12 is penetrated through the through hole 20A of the boot 20 and the boot 20 is elastically deformed when a force is applied to the covering portion 33 of the tape-shaped multi-core optical fiber 12 in the bending direction. In addition, bending of the tape-shaped multi-core optical fiber 12 is prevented.

  In this bent connector structure 10, the covering portion 33 at the base side of the bent portion 32 </ b> A of the tape-shaped multi-core optical fiber 12 is bonded and fixed to the insertion portion 24 </ b> A of the ferrule body 16, the lid member 18 and the boot 20 with a high viscosity adhesive 36. ing. Further, the tip end portion 32B of the tape-shaped multi-core optical fiber 12 is bonded and fixed to the groove portion 26 of the ferrule body 16 and the lid member 18 with an adhesive 38 such as an epoxy resin generally used for connectors. The bent portion 32A of the tape-shaped multi-fiber optical fiber 12 is not in contact with the wall surface of the recess 16A of the ferrule body 16 and the inner wall surface of the lid member 18, and a cavity S is provided around the bent portion 32A.

  That is, the covering portion 33 and the ferrule 14 of the tape-shaped multi-core optical fiber 12 are sealed with the high-viscosity adhesive 36, and the tip portion 32 B of the tape-shaped multi-core optical fiber 12 and the ferrule 14 are bonded and fixed with the adhesive 38. Thus, the cavity S of the ferrule body 16 in which the bent portion 32A of the tape-shaped multi-core optical fiber 12 is accommodated becomes a sealed space. Air is sealed in the cavity S. The air sealed in the cavity S around the bent part 32A has a lower refractive index than the resin filled around the conventional bent part, and the refractive index of the core layer of the bare optical fiber 32 and the cavity S A sufficient refractive index difference with air can be obtained.

  As the adhesive 38, for example, a thermosetting resin such as an epoxy resin, a cyanoacrylate-based instantaneous adhesive, an ultraviolet curable resin, or the like is used. The high-viscosity adhesive 36 is an adhesive having a higher viscosity than the adhesive 38 such as an epoxy resin generally used for connectors. For example, the viscosity of the high-viscosity adhesive 36 is preferably 50 to 300 Pa · s. If the viscosity of the high-viscosity adhesive 36 is below the lower limit of the above range, the adhesive may flow out, and if it exceeds the upper limit of the above range, it may not enter the adhesive surface of the adhesive. As the high-viscosity adhesive 36, for example, a two-component mixed epoxy resin that cures at room temperature is used.

  As shown in FIG. 1, notch portions 40 are formed on both sides in the width direction on the groove portion 26 side of the upper surface portion of the ferrule body 16, and guide pin holes 42 are respectively formed in the notch portions 40. Cylindrical guide pins (not shown) are fitted in the two guide pin holes 42 to be positioned and fixed with respect to other elements such as other connectors and boards. By making the positional relationship between the guide pin hole 42 and the groove 26 precise, the guide pin hole 42 and the guide pin on the side of the substrate and the like are precisely connected to the tip end portion 32B of the tape-shaped multi-core optical fiber 12. Optical coupling with the connectors and optical elements to be achieved can be achieved.

  The surfaces of the ferrule body 16 and the lid member 18 through which the tip portion 32B of the tape-shaped multi-core optical fiber 12 is inserted are provided with polished surfaces 16B and 18F polished together with the tip portion 32B of the tape-shaped multi-fiber optical fiber 12. ing. Thereby, connection loss when an optical fiber of another connector (not shown) is connected is reduced.

  Next, a method for producing the bent connector structure 10 will be described.

  As shown in FIG. 3, the covering portion 33 of the tape-shaped multi-core optical fiber 12 is inserted into the insertion portion 24A of the ferrule main body 16, and the bent portion 32A of the tape-shaped multi-core optical fiber 12 is inserted into the recess 16A of the ferrule main body 16. Store in. Further, the tips 32 B of the plurality of bare optical fibers 32 are fitted into the plurality of grooves 26 formed in the ferrule body 16, and the ends of the bare optical fibers 32 are exposed to the outside of the ferrule body 16.

  In this state, the lid member 18 is inserted into the recess 16 </ b> A of the ferrule body 16, and the portion where the bent portion 32 </ b> A of the tape-shaped multi-core optical fiber 12 is accommodated is covered with the lid member 18. Then, a high-viscosity adhesive 36 is filled between the covering portion 33 of the tape-shaped multi-core optical fiber 12, the insertion portion 24 </ b> A of the ferrule body 16, and the lid member 18. Further, the through-hole 20A of the boot 20 is filled with the high-viscosity adhesive 36, and the protrusion 20B of the boot 20 is extrapolated to the side wall 24 of the ferrule body 16 and the notch 18D of the lid member 18. As a result, the high-viscosity adhesive 36 is filled in the gap between the inside of the protruding portion 20 </ b> B of the boot 20 and the lid member 18. As the high-viscosity adhesive 36, a two-component mixed epoxy resin that cures at room temperature is used, and when the high-viscosity adhesive 36 is cured, the tape-shaped multi-core optical fiber 12 is made of the ferrule body 16 and the lid member 18. And are fixed to the boot 20 by adhesion.

  Further, as shown in FIG. 1 and FIG. 3, it is generally used for connectors in the gaps between the tip portions 32 </ b> B of the plurality of bare optical fibers 32, the plurality of grooves 26 of the ferrule body 16, and the lid member 18. Fill with adhesive 38 and cure.

  The distal end portion 32B of the bare optical fiber 32 is cut in the vicinity of the end faces of the ferrule body 16 and the lid member 18, and the surfaces of the ferrule body 16 and the lid member 18 are polished together with the cut end faces of the bare optical fiber 32. 16B and 18F are formed. In this bent connector structure 10, cylindrical guide pins (not shown) are respectively fitted in the two guide pin holes 42 of the ferrule body 16, and these guide pins are connected to another multi-core ferrule connector (not shown). By fitting into the guide pin hole, it can be connected to an external element such as another connector.

  In this bent connector structure 10, the optical axis of the tape-shaped multi-core optical fiber 12 is bent by 90 degrees by the ferrule 14. For example, the optical axis of the tape-shaped multi-fiber optical fiber 12 is bent by 90 to 150 degrees. It may be configured. The bent portion 32A of the tape-shaped multi-core optical fiber 12 preferably has a curvature of r = 0.5 to 3 mm, for example. If r is below the lower limit of the above range, the bending loss will be too large, and if r exceeds the upper limit of the above range, the connector size will be large.

  Next, the operation and effect of the bending connector structure 10 of the present embodiment will be described.

  In this bent connector structure 10, the covering portion 33 of the tape-shaped multi-core optical fiber 12 is bonded and fixed to the ferrule body 16, the lid member 18, and the boot 20 with a high-viscosity adhesive 36, and the tip portion of the tape-shaped multi-core optical fiber 12 is secured. 32B is bonded and fixed to the ferrule body 16 and the lid member 18 with an adhesive 38, so that the cavity S of the ferrule body 16 in which the bent portion 32A of the tape-shaped multi-core optical fiber 12 is housed is sealed with air. It is said that. Accordingly, since there is a sufficient refractive index difference between the refractive index of the core layer of the bare optical fiber 32 and the air in the cavity S at the bent portions 32A of the plurality of bare optical fibers 32, the bending loss is reduced. The When the ambient temperature changes, the air sealed in the sealed space around the bent portion 32A has less variation in the refractive index than, for example, the refractive index of the resin filled in the conventional cavity S. Therefore, it is possible to suppress the optical characteristics of the bent connector structure 10 such as the light confinement effect from fluctuating due to the environmental temperature. Furthermore, since a sealed space is formed around the bent portion 32A, dust or the like does not enter and adhere from the outside of the ferrule 14, and bending loss can be reduced.

  Next, 2nd Embodiment of the bending connector structure of this invention is described using FIGS. 4-6. In addition, the same code | symbol is attached | subjected to the member same as 1st Embodiment, and the overlapping description is abbreviate | omitted.

  As shown in FIGS. 4 to 6, the bending connector structure 50 includes an attachment 54 that is attached to an end of the ferrule body 52 on the groove 26 side. The attachment 54 includes a plurality of fiber holding holes 56 that respectively hold the tip portions 32B of the plurality of bare optical fibers 32 protruding from the grooves 26 of the ferrule body 52, and two guides formed on the left and right sides of the fiber holding holes 56. Pin hole 58. At the end of the ferrule body 52 on the groove 26 side, a notch 52A is formed by notching both sides in the width direction, and the recess 54A formed in the attachment 54 is fitted into the notch 52A. (See FIG. 6).

  A tapered hole 57 having a gradually increased width is provided at the insertion side end of the fiber holding hole 56 of the attachment 54 (see FIG. 5). By providing the tapered hole 57, it becomes easy to insert the tip portions 32B of the plurality of bare optical fibers 32 into the plurality of fiber holding holes 56.

  When attaching the attachment 54 to the ferrule body 52, the distal end portions 32 </ b> B of the plurality of bare optical fibers 32 inserted through the groove portions 26 of the ferrule body 52 are inserted into the fiber holding holes 56 of the attachment 54. Then, the attachment 54 is fixed to the ferrule body 52 with the adhesive 38. Further, the end surface of the attachment 54 is polished together with the tip portions 32B of the plurality of bare optical fibers 32 protruding from the fiber holding holes 56 of the attachment 54, thereby providing a polishing surface 54B.

  In this bent connector structure 50, as shown in FIG. 5, the covering portion 33 of the tape-shaped multi-core optical fiber 12 inserted through the insertion portion 24A of the ferrule body 52 is connected to the insertion portion 24A of the ferrule body 52, the lid member 18, and the like. The boot 20 is bonded and fixed to the boot 20 with a high-viscosity adhesive 36, and the distal ends 32 </ b> B of the plurality of bare optical fibers 32 are bonded and fixed to the fiber holding holes 56 of the attachment 54 with an adhesive 38. The periphery of the bent portions 32A of the plurality of bare optical fibers 32 surrounded by the ferrule main body 52 and the lid member 18 and the periphery of the plurality of bare optical fibers 32 inside the attachment 54 form a sealed space. Air is sealed in the space.

  In this bent connector structure 50, guide pins (not shown) are fitted into the two guide pin holes 58, respectively, and these guide pins are connected to guide pin holes of another multi-core ferrule connector (MT connector) (not shown). By being fitted in, it can be connected to another connector such as an MT connector.

  In such a bent connector structure 50, the periphery of the bent portion 32A of the tape-shaped multi-core optical fiber 12 housed in the concave portion 16A of the ferrule body 52 is a sealed space in which air is enclosed. By enclosing air having a lower refractive index than that of the resin filled in the periphery, it is possible to suppress the optical characteristics of the bent connector structure 50 from fluctuating due to the environmental temperature. Further, since the sealed space around the bent portion 32A of the tape-shaped multi-fiber optical fiber 12 is formed, dust or the like does not flow in and adhere from the outside of the ferrule body 52, the lid member 18 and the attachment 54, and the bending loss. Can be reduced. Further, the bending connector structure 50 improves the positional accuracy as compared with the structure in which the distal end portions 32 of the plurality of bare optical fibers 32 are fixed by V-shaped grooves, and is also convenient for the SM fiber.

  [Supplementary explanation of the embodiment]

  In the bent connector structures 10 and 50 of the first and second embodiments described above, air is sealed in the sealed space around the bent portion 32A of the tape-shaped multi-core optical fiber 12, but the present invention is not limited to this. A gas having low properties (for example, an inert gas such as argon, nitrogen, or helium) may be enclosed. It is most preferable that the cavity including the bent part is completely sealed, but the atmosphere of the cavity is not changed by the air flow (for example, cooling air) in the use environment, or dust in the atmosphere is not mixed. It is sufficient that the gap is larger than 1 mm in the region surrounding the cavity, or the opening is not provided, more preferably in the gap between the members, or the gap between the optical fiber and the member. This can be realized by injecting resin or adhesive. The optical characteristics of the bent connector structure 50 fluctuate depending on the ambient temperature by enclosing a gas having a lower refractive index in the periphery of the bent portion than the low refractive index resin conventionally attached to the bent portion of the optical fiber. Can be suppressed. Furthermore, the sealed space may be in a vacuum state.

  In the bent connector structures 10 and 50 of the first and second embodiments, the optical axis of the tape-shaped multi-core optical fiber 12 is bent by 90 degrees by a ferrule including a ferrule body and a lid member. Is not to be done. In the bent connector structure, the optical axis of the tape-shaped multi-core optical fiber 12 can be configured to be bent by 90 degrees to 150 degrees. FIG. 7 shows an example in which bent connectors bent at 135 degrees are arranged in a dense array. As shown in this figure, a plurality of bent connectors 100 bent at 135 degrees are mounted on an electric circuit board 120. In this structure, the optical fiber 110 extending from the bending connector 100 can be released obliquely upward. For this reason, the thickness on a board | substrate can be made thin compared with the connector in which the conventional optical axis is not bent, or it has the characteristics that it can be made dense compared with a 90 degree | times bending connector.

  Further, in the bent connector structures 10 and 50 of the first and second embodiments, the ferrule including the ferrule body and the lid member is used, but the present invention is not limited to this. In the bent connector structure, the bent portion 32A of the tape-shaped multi-core optical fiber 12 is accommodated, the base side of the tape-shaped multi-core optical fiber 12 is fixed to the first fixed portion, and the tip of the tape-shaped multi-core optical fiber 12 is fixed. Any other configuration may be used as long as 32B can be fixed to the second fixing portion. For example, a ferrule formed integrally may be used.

10 Bent connector structure 12 Tape-like multi-core optical fiber (tape-like optical fiber)
14 Ferrule 16 Ferrule body 16A Concave part (hollow part)
16B Polishing surface 18 Lid member 18F Polishing surface 20 Boot (protective member)
20A Through-hole 20C Tapered surface 22 Bottom surface portion 24 Side wall 24A Insertion portion (first fixing portion)
26 Groove 28 Recess 32 Bare Optical Fiber 32A Bend 32B Tip 33 Cover 36 High Viscosity Adhesive 38 Adhesive 50 Bend Connector Structure 52 Ferrule Main Body 54 Attachment 54B Polishing Surface 56 Fiber Holding Hole (Holding Hole)

Claims (16)

An optical fiber formed with a bent portion;
A first fixing portion inserted and fixed on one side of the bent portion of the optical fiber; a cavity portion storing the bent portion; and a tip portion of the optical fiber on the other side of the bent portion inserted. A ferrule provided with a fixed second fixing portion, and
The bent portion is not in contact with the wall surface of the cavity, and the cavity is a sealed space ;
The ferrule has a ferrule body in which the cavity is formed, and a lid member that covers the cavity and serves as a sealed space,
A bending connector structure in which the ferrule body and the lid member are provided with a hollow portion that widens the wall surface of the cavity portion from the second fixing portion to the bending portion .   The bent connector structure according to claim 1, wherein the bent portion is formed by bending a bare optical fiber excluding the coating of the optical fiber.   The bending connector structure according to claim 1 or 2, wherein air or inert gas is sealed in the sealed space. The bending connector structure according to any one of claims 1 to 3 , wherein the ferrule body is formed with a groove portion that constitutes the second fixing portion and into which a tip portion of the optical fiber is fitted . The tip portion of the optical fiber is bonded and fixed to the second fixing portion with an epoxy resin adhesive,
According to any one of claims 1 to proximal portion of the optical fiber viscosity than the epoxy resin-based adhesive to said first fixing portion is bonded and fixed at a high viscous adhesive to claim 4 Bending connector structure. The bending connector structure according to any one of claims 1 to 5 , wherein a polishing surface polished with a tip portion of the optical fiber is provided on a surface of the ferrule on the second fixed portion side . The bending connector structure according to any one of claims 1 to 5 , wherein an attachment having a holding hole for the optical fiber is attached to the second fixing portion of the ferrule . The bending connector structure according to claim 7 , wherein an attachment-side polishing surface polished with the optical fiber is provided on a surface of the attachment . The bending connector structure according to any one of claims 1 to 8 , wherein the bent portion is formed to have a curvature of r = 0.5 to 3 mm . The bending connector structure according to any one of claims 1 to 9 , wherein the optical fiber is a tape-like optical fiber in which a plurality of optical fibers are arranged . The bending connector structure according to claim 5 , wherein the high-viscosity adhesive has a viscosity of 50 to 300 Pa · s . 2. The flexible protective member is attached to the first fixing portion of the ferrule. The flexible protective member covers the optical fiber and has an inner surface formed with a tapered surface whose diameter increases toward the ferrule. The bending connector structure according to any one of claims 11 to 11. The bending connector structure according to claim 12 , wherein the protective member is formed of a plastic made of soft rubber or elastomer . The bending connector structure according to claim 1 , wherein the bent portion is bent by heat . The bending connector structure according to any one of claims 1 to 14 , wherein an optical axis of the optical fiber is bent by 90 to 150 degrees by the ferrule . The bending connector structure according to claim 4 , wherein the grooves are arranged at a pitch of 250 μm or 125 μm .

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