JP2006010871A - Optical fiber connector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical fiber connector capable of reducing a connection loss of an optical fiber even when connecting optical fibers without exposing a bare fiber part.
An optical fiber connector (1) includes a base (5) and a holding part (6), and includes a fiber holding member (7) that holds a pair of optical fibers (2) sandwiched from above and below. The base (5) positions the optical fiber (2). For this purpose, a stepped fiber groove 9 having a V-shaped cross section is provided. The stepped fiber groove 9 includes a covering deformation groove portion 10 and a covering holding groove portion 11 formed so as to sandwich the covering deformation groove portion 10 and having a depth and width larger than the covering deformation groove portion 10. is doing. In the fiber holding member 7, the coating deformation groove portion 10 of the base portion 5 and the portion corresponding to the coating deformation groove portion 10 in the pressing surface 6 a of the pressing portion 6 are the covering portions 4 formed at the distal end portion of each optical fiber 2. A tip covering positioning portion 15 is positioned which is compressed and deformed for positioning.
[Selection] Figure 1

Description

  The present invention relates to an optical fiber connector for connecting optical fibers formed by forming a covering portion around a bare fiber portion.

As an optical fiber connector for connecting optical fibers to each other, for example, the one described in Patent Document 1 is known. An optical fiber connector described in this document includes a base having a V-groove for positioning and aligning an optical fiber, and a lid having a fiber holding groove for holding an optical fiber formed in a region facing the V-groove. And a C-type spring for applying a pressure-contacting force for interposing the base and the lid in pressure contact with each other.
JP-A-9-61655

  In the above optical fiber connector, the V-groove of the base includes a connection part for positioning the bare fiber part of the optical fiber and a coating support part for positioning the coating part of the optical fiber. For this reason, it is necessary to remove the coating portion of the optical fiber to expose the bare fiber portion and to further cut the end face of the bare fiber portion. Therefore, the work man-hour for connecting optical fibers increases. In addition, an expensive dedicated tool for removing the coated portion of the optical fiber and cutting the end face of the bare fiber portion is required. For this reason, it is strongly desired to connect the optical fibers without exposing the bare fiber portion of the optical fiber.

  However, in the optical fiber, the dimensional variation of the covering portion is generally larger than the dimensional variation of the bare fiber portion. Some optical fibers have so-called eccentricity of the bare fiber portion in which the center of the bare fiber portion and the center of the covering portion do not coincide with each other. For this reason, when the optical fibers in which the bare fiber portions at the distal ends are covered with the covering portion, for example, in the V-groove, the center axis of each bare fiber portion may be greatly displaced. Connection loss increases.

  The objective of this invention is providing the optical fiber connector which can reduce the connection loss of an optical fiber, even when connecting optical fibers, without exposing a bare fiber part.

  The present invention is an optical fiber connector for connecting at least one pair of optical fibers having a coating portion formed around a bare fiber portion, and a fiber holding member that holds each optical fiber in a butted state The fiber holding member is provided with a tip coating positioning portion that positions the coating portion formed at the tip portion of each optical fiber by compressive deformation.

  When connecting optical fibers using such an optical fiber connector, each optical fiber is covered by a fiber holding member while the bare fiber portion at the tip of each optical fiber is covered with a covering portion without being exposed. Hold in a state where they face each other. At this time, the fiber holding member is provided with a tip coating positioning portion that compresses and positions the coating portion formed at the tip portion of each optical fiber, so that the eccentricity of the bare fiber portion (the uneven thickness of the coating portion) is provided. ) Is large, the absolute value of the uneven thickness of the covering portion becomes small due to the compressive deformation of the covering portion. And a bare fiber part will be positioned with the compressive deformation of a coating | coated part. Thereby, since the center-axis shift | offset | difference of each bare fiber part of the optical fiber which opposes is reduced, the increase in the connection loss of an optical fiber can be suppressed.

  Preferably, the fiber holding member has a base portion provided with a fiber groove for positioning each optical fiber, and a pressing portion that presses each optical fiber disposed in the fiber groove against the base portion. The tip covering positioning portion is formed by the pressing surface of the pressing portion. When connecting the optical fibers, the optical fibers are arranged so as to face each other in the fiber groove of the base, and the optical fibers are sandwiched by pressing the pressing portion against the base in this state. At this time, in the distal end covering positioning portion of the fiber holding member, the distal end portion of each optical fiber is pushed into the fiber groove, and the covering portion is easily and reliably compressed and deformed into a shape along the fiber groove.

  At this time, the fiber groove is formed so as to sandwich the covering deformation groove portion forming the tip covering positioning portion, and the covering holding groove portion having a depth and width larger than the covering deformation groove portion. It is preferable that a covering pressing groove is provided in a portion corresponding to the covering holding groove portion in the pressing portion. In this case, since the tip coating positioning part exists only in a part of the fiber holding member, the load applied to compress and deform the coating part of each optical fiber into a shape along the fiber groove is lowered. be able to.

  Preferably, the fiber holding member has a tapered portion whose diameter increases from the center side toward both ends, and is provided with a fiber hole for positioning and holding each optical fiber. A portion including a part of the tapered portion in the hole forms a tip covering positioning portion having a diameter smaller than the outer diameter of the covering portion of the optical fiber. When connecting optical fibers, each optical fiber is inserted into the fiber hole from both sides of the fiber holding member and abutted. At this time, since the diameter of the fiber hole is smaller than the outer diameter of the coating portion of the optical fiber in the tip coating positioning portion of the fiber holding member, the coating portion formed at the tip portion of each optical fiber is easily along the taper portion. In addition, it comes to compressively deform.

  Further, the present invention is an optical fiber connector for connecting at least one pair of optical fibers formed by forming a covering portion around a bare fiber portion, comprising a fiber holding member for holding the optical fiber, The fiber holding member is provided with a tip coating positioning portion for compressing and positioning the coating portion formed at the tip portion of the optical fiber.

  When connecting optical fibers using such an optical fiber connector, two sets of optical fiber connectors in a state where the optical fiber is held and fixed to the fiber holding member are prepared. The optical fibers are butted against each other. At this time, the fiber holding member is provided with a tip coating positioning portion that compresses and positions the coating portion formed on the tip portion of the optical fiber, so that the eccentricity of the bare fiber portion (unevenness of the coating portion) is provided. Even when is large, the absolute value of the uneven thickness of the covering portion is reduced by the compressive deformation of the covering portion. And the bare fiber part is in the state positioned with the compressive deformation of the covering part. Thereby, when each optical fiber is faced | matched, since the center-axis shift | offset | difference of each bare fiber part of the optical fiber which opposes is reduced, the increase in the connection loss of an optical fiber can be suppressed.

  Preferably, the fiber holding member has a base portion provided with a fiber groove for positioning the optical fiber, and a pressing portion that presses the optical fiber disposed in the fiber groove against the base portion. The tip covering positioning portion is formed with the pressing surface of the portion. When the optical fiber is held by the fiber holding member, the optical fiber is disposed in the fiber groove of the base, and the optical fiber is sandwiched by pressing the pressing portion against the base in this state. At this time, at the distal end covering positioning portion of the fiber holding member, the distal end portion of the optical fiber is pushed into the fiber groove, and the covering portion is simply and reliably compressed and deformed into a shape along the fiber groove.

  At this time, the fiber groove is provided at one end portion of the fiber holding member, and is provided at the other end side of the fiber holding member with respect to the coating deformation groove portion that forms the tip coating positioning portion, and the coating deformation groove portion. It is preferable that the cover holding groove portion has a depth and width larger than the groove portion, and the cover pressing groove is provided in a portion corresponding to the coating holding groove portion in the pressing portion. In this case, since the tip coating positioning portion exists only in a part of the fiber holding member, when the optical fiber is held by the fiber holding member, the shape of each optical fiber coating portion is formed along the fiber groove. The load applied for compressive deformation can be reduced.

  Preferably, the fiber holding member has a tapered portion whose diameter increases from one end side to the other end side, and is provided with a fiber hole for positioning and holding each optical fiber, A portion including a part of the tapered portion in the fiber hole forms a tip coating positioning portion having a diameter smaller than the outer diameter of the coating portion of the optical fiber. When the optical fiber is held by the fiber holding member, the optical fiber is inserted into the fiber hole from one side of the fiber holding member (the side having the larger diameter of the fiber hole). At this time, since the diameter of the fiber hole is smaller than the outer diameter of the coating portion of the optical fiber in the tip coating positioning portion of the fiber holding member, the coating portion formed at the tip portion of each optical fiber is easily along the taper portion. In addition, it comes to compressively deform.

  Further, preferably, the bare fiber portion protrudes 10 to 1000 nm from the end face of the covering portion. When such an optical fiber is used, when the optical fiber is held by the fiber holding member, even if the amount of compressive deformation of the coating formed at the tip of the optical fiber is large, the coating with respect to the fiber axial direction A sufficient clearance space for deformation is secured. Thereby, bare fiber parts can be reliably faced | matched at the time of connection of optical fibers.

  ADVANTAGE OF THE INVENTION According to this invention, even when connecting optical fibers, without exposing the bare fiber part of an optical fiber, the connection loss of an optical fiber can be reduced. Accordingly, it is not necessary to remove the coating portion of the optical fiber or cut the end face of the bare fiber portion of the optical fiber, which is advantageous in terms of workability and cost.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of an optical fiber connector according to the invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a first embodiment of an optical fiber connector according to the present invention, FIG. 2 is a cross-sectional view taken along the line II-II in FIG. 1, and FIG. It is III sectional view. In each figure, the optical fiber connector 1 of the present embodiment is a mechanical splice for abutting and connecting a pair of optical fibers 2 to each other. As the optical fiber 2, either a single mode fiber or a multimode fiber can be used. The optical fiber 2 includes a bare fiber glass portion 3 composed of a core and a clad, and a covering portion 4 formed around the bare fiber glass portion 3.

The optical fiber connector 1 includes a base portion 5 and a pressing portion 6, a fiber holding member 7 that holds a pair of optical fibers 2 sandwiched from above and below, and a U-shaped cross section that fastens the base portion 5 and the pressing portion 6 from above and below. The clamp member 8 is provided. The fiber holding member 7 is formed of a material having a Young's modulus of 7.8 × 10 ⁸ to 7.8 × 10 ¹⁰ [Pa], for example, ceramics such as zirconia, plastic such as polyphenylene sulfide, epoxy resin, and fluorine resin. Yes.

  The base 5 is provided with a stepped fiber groove 9 having a V-shaped cross section for positioning the optical fiber 2. The stepped fiber groove 9 may have a U-shaped cross section. The stepped fiber groove 9 includes a coating deformation groove portion 10 formed at the longitudinal center of the base portion 5 and two coating holding groove portions formed at both ends of the base portion 5 so as to sandwich the coating deformation groove portion 10. 11. The covering deformation groove portion 10 and the covering holding groove portion 11 have a similar shape, and the depth and width of the covering deformation groove portion 10 are smaller than the depth and width of the covering holding groove portion 11. At this time, the depth of the coating deformation groove portion 10 is, for example, 2 to 3 times the diameter of the bare fiber glass portion 3 of the optical fiber 2. A taper portion 12 is provided between the covering deformation groove portion 10 and each covering holding groove 11.

  A covering pressing groove 13 having a rectangular cross section is formed at a portion of the pressing portion 6 corresponding to each covering holding groove portion 11. That is, the pressing surface 6 a that presses the optical fiber 2 from above in the pressing portion 6 has a step shape corresponding to the stepped fiber groove 9. Further, the pressing surface 6 a has a tapered portion 14 corresponding to the tapered portion 12 of the stepped fiber groove 9.

  In such a fiber holding member 7, the covering deformation groove portion 10 of the base portion 5 and the portion corresponding to the covering deformation groove portion 10 in the pressing surface 6 a of the pressing portion 6 are pressed against the base portion 5. In addition, a tip covering positioning portion 15 for positioning the covering portion 4 formed at the tip end of each optical fiber 2 by compressing and deforming is configured. That is, when the pressing portion 6 is pressed against the base portion 5 with the covering portion 4 of each optical fiber 2 in the covering deformation groove portion 15, a load is applied to the optical fiber 2 as shown in FIGS. The optical fiber 2 is pushed into the coating deformation groove 10, and the coating portion 4 of the optical fiber 2 is compressed and deformed into a substantially triangular shape along the tip coating positioning portion 15.

  At this time, since the tip covering positioning portion 15 is formed only at the center portion of the fiber holding member 7, a desired compressive deformation of the covering portion 4 can be obtained with a low load. The angle of the V-shaped apex of the stepped fiber groove 9 is 30 to 120 degrees, but in order to apply a load evenly to the optical fiber 2, the angle is most preferably about 60 degrees. Further, the amount of deformation of the covering portion 4 is desirably 20 to 100% with respect to the initial thickness of the covering portion 4.

  The covering holding groove portion 11 of the base portion 5 and the covering pressing groove 13 of the pressing portion 6 are configured to be able to hold the coating portion 4 of the optical fiber 2 with almost no deformation. Further, since the stepped fiber groove 9 is provided with a tapered portion 12, and the pressing surface 6a of the pressing portion 6 is provided with a tapered portion 14, the bare fiber glass portion 3 generated when the covering portion 4 is compressed and deformed. It is possible to reduce the bending loss.

  A wedge insertion groove 16 into which a wedge (not shown) for opening the base portion 5 and the pressing portion 6 is inserted is provided on one side surface portion (the side surface portion on the open side of the clamp member 8) of the fiber holding member 7. ing. The wedge insertion groove 16 is constituted by a notch 16 a formed in the base portion 5 and the pressing portion 6.

  When connecting the two optical fibers 2 using the optical fiber connector 1 configured as described above, first, a wedge (not shown) is inserted into the wedge insertion groove 16 of the fiber holding member 7, The base portion 5 and the pressing portion 6 are opened against the elastic force of the clamp member 8. In this state, the optical fiber 2 is introduced into the stepped fiber groove 9 of the base portion 5 from both ends of the fiber holding member 7, and the optical fibers 2 are butted together at the center portion (tip covering positioning portion 15) of the fiber holding member 7. . When the wedge is pulled out, each optical fiber 2 is sandwiched and held between the base portion 5 and the pressing portion 6 by the elastic force of the clamp member 8. Then, as described above, the coating portion 4 of each optical fiber 2 is compressed and deformed along the coating deformation groove portion 10 (see FIGS. 4 and 5), and the tip portion of each optical fiber 2 is positioned in this state.

By the way, in the optical fiber 2 in which the bare fiber glass part 3 is covered with the covering part 4, the center of the bare fiber glass part 3 and the center of the covering part 4 may not coincide as shown in FIG. The uneven thickness of the part 4 occurs. The uneven thickness of the covering portion 4 is defined by the uneven thickness ratio calculated by the following formula.
Uneven thickness rate (%) = _Dmin / _Dmax × 100

  In addition, in the optical fiber 2, the variation in the diameter of the covering portion 4 is usually larger than the variation in the diameter of the bare fiber glass portion 3. For this reason, if the optical fibers 2 are positioned in the fiber grooves and simply abutted, the center axes of the bare fiber glass portions 3 may be greatly displaced.

  For example, when the non-uniform thickness ratio of the optical fiber 2 is 93%, the thickness difference of the covering portion 4 is 5 μm, and the deviation between the center of the bare fiber glass portion 3 and the center of the covering portion 4 is 2.5 μm. Become. Further, when the non-uniform wall thickness ratio of the optical fiber 2 is 70%, the thickness difference of the covering portion 4 is 20 μm, and the deviation between the center of the bare fiber glass portion 3 and the center of the covering portion 4 is 10 μm. Here, when the optical fibers 2 having the same thickness ratio are abutted with each other, the axial misalignment of each bare fiber glass portion 3 becomes a value twice as large as the above-mentioned center misalignment. That is, when the non-uniform thickness ratio of the optical fiber 2 is 93%, the axial misalignment of each bare fiber glass portion 3 is 5 μm at the maximum, and when the non-uniform thickness ratio of the optical fiber 2 is 70%, The axial deviation of the bare fiber glass part 3 is 20 μm at the maximum.

  When the optical fibers 2 are brought into contact with each other as described above, the connection loss of the optical fibers 2 is increased if the axial misalignment of the bare fiber glass portions 3 is large. Specific numerical values of connection loss due to shaft misalignment are shown in FIG. For example, when the mode field diameter (MFD) of the optical fiber 2 is 50 μm, the connection loss is 0.2 dB when the axial deviation is 5 μm, and the connection loss is 2.8 dB when the axial deviation is 20 μm.

  On the other hand, in the present embodiment, not only the optical fibers 2 are butted together, but also the end covering positioning portion 15 is provided on the fiber holding member 7 so that the covering portion 4 formed at the end of each optical fiber 2 is compressed and deformed. Try to match in the state of letting. Thereby, even if the thickness variation of the coating portion 4 of each optical fiber 2 is large, the absolute value of the thickness variation of the coating portion 4 is reduced by the compressive deformation of the coating portion 4 at the distal end portion by the distal end coating positioning portion 15. The leading end portion of the bare fiber glass portion 3 is guided and positioned along the coating deformation groove portion 10 as the coating portion 4 is compressed and deformed. As a result, the axial misalignment of each bare fiber glass portion 3 is reduced.

  Accordingly, even when the optical fibers 2 are connected to each other with the tip of the bare fiber glass portion 3 covered with the covering portion 4, the connection loss of the optical fiber 2 can be reduced. This eliminates the need to remove the coating portion 4 of the optical fiber 2 to expose the bare fiber glass portion 3 or to cut the front end surface of the bare fiber glass portion 3 vertically as in the prior art. Workability for connecting the two is improved. Moreover, since an expensive dedicated tool for removing the covering portion 4 and cutting the end face of the bare fiber glass portion 3 is not required, the cost can be reduced.

  Here, as the optical fiber 2 in the initial state, the end face of the bare fiber glass portion 3 and the end face of the covering portion 4 are flush with each other, or the bare fiber glass portion 3 is slightly from the end face of the covering portion 4. Although there are some protruding (about 10 to 1000 nm), it is not necessary to remove the covering portion 4 at the time of fiber connection for any of the optical fibers 2.

  When the optical fiber 2 in which the bare fiber glass portion 3 protrudes slightly from the end face of the covering portion 4 is used, the clearance space of the covering portion 4 with respect to the fiber axial direction is maintained. For this reason, when the optical fibers 2 are connected to each other, the amount of compressive deformation of the covering portion 4 by the tip covering positioning portion 15 of the fiber holding member 7 is large, and even if the covering portion 4 protrudes in the fiber axis direction, the bare fiber glass portions 3 It is possible to sufficiently ensure the butting state.

  On the other hand, when using the optical fiber 2 in which the end surface of the bare fiber glass portion 3 and the end surface of the covering portion 4 are flush with each other, the compression of the covering portion 4 of the optical fiber 2 is performed when the optical fibers 2 are connected to each other. When the amount of deformation is large, the coating portion 4 protrudes in the fiber axis direction, so that a gap may be formed between the bare fiber glass portions 3. In this case, the optical fibers 2 may be abutted against each other in a state where a refractive index matching agent is filled between the two optical fibers 2. As the refractive index matching agent, silicone oil, grease, resin or the like is used. Thereby, it becomes possible to suppress an increase in connection loss of the optical fiber 2.

  In the present embodiment, the tip coating positioning portion 15 is formed at the center of the fiber holding member 7, but the tip coating positioning portion 15 may be formed in the entire longitudinal direction of the fiber holding member 7. In this case, since the fiber groove 9 of the base 5 and the pressing surface 6a of the pressing portion 6 do not need to be stepped, the fiber holding member 7 can be easily manufactured.

  Further, in this embodiment, the fiber holding member 7 that holds the optical fiber 2 is configured by the base 5 and the pressing portion 6, but is not particularly limited thereto, and may have, for example, a collet chuck structure. .

  FIG. 8 is a sectional view showing a second embodiment of the optical fiber connector according to the present invention, and FIG. 9 is a front view of the optical fiber connector shown in FIG. In the figure, the same or equivalent members as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In each figure, the optical fiber connector 20 of this embodiment is another form of mechanical splice, and is composed of a cylindrical fiber holding member 21. The fiber holding member 21 is formed of the same material as the fiber holding member 7 in the first embodiment. The fiber holding member 21 is provided with a fiber hole 22 having a circular cross section for positioning and holding the pair of optical fibers 2.

  The fiber hole 22 is formed on the both ends of the fiber holding member 21 so as to sandwich the constant diameter portion 23 formed between the constant diameter portion 23 and the fiber holding member from the constant diameter portion 23. 21 and two tapered portions 24 having diameters that increase toward both ends. The diameter of the fiber hole 22 at both ends of the fiber holding member 21 is larger than the outer diameter of the coating portion 4 of the optical fiber 2. Thereby, the optical fiber 2 can be easily inserted into the fiber hole 22. The diameter of the equal diameter portion 23 is larger than the outer diameter of the bare fiber glass portion 3 of the optical fiber 2 and smaller than the outer diameter of the covering portion 4.

  The equal diameter portion 23 in the fiber hole 22 and a part of the taper portion 24 (portion having a diameter smaller than the outer diameter of the covering portion 4) compress the covering portion 4 formed at the distal end portion of each optical fiber 2. A tip covering positioning portion 25 is formed which is deformed and positioned.

  When connecting two optical fibers 2 using such an optical fiber connector 20 (fiber holding member 21), each optical fiber 2 is inserted into the fiber hole 22 from both ends of the fiber holding member 21. , Push in. Then, as shown in FIG. 10, in the tip coating positioning part 25, the coating part 4 formed at the tip part of each optical fiber 2 is compressed and deformed along the taper part 24, and in this state, each optical fiber 2 is a fiber. It is held by the holding member 21 so that the optical fibers 2 come into contact with each other.

  In the present embodiment as described above, even when the thickness of the coating portion 4 of each optical fiber 2 is large, the coating portion 4 at the tip portion of each optical fiber 2 is the tip coating positioning portion 25 of the fiber holding member 21. Therefore, the absolute value of the thickness deviation of the covering portion 4 is reduced, and the distal end portion of the bare fiber glass portion 3 is guided and positioned along the tapered portion 24 along with the compressive deformation of the covering portion 4. The Therefore, as in the first embodiment, since the axial displacement of each bare fiber glass portion 3 is reduced, the connection loss of the optical fiber 2 can be reduced. Thereby, removal of the coating | coated part 4 of the optical fiber 2, and the end surface cut of the bare fiber glass part 3 become unnecessary.

  In this embodiment as well, a refractive index matching agent may be filled between the optical fibers 2 when the optical fibers 2 are connected to each other.

  FIG. 11 is a cross-sectional view showing a third embodiment of an optical fiber connector according to the present invention. In the drawing, the same reference numerals are given to the same or equivalent members as those of the above-described embodiment, and the description thereof is omitted.

  In the figure, optical fiber connectors 30A and 30B of the present embodiment are guide pin reference type optical fiber connectors. The optical fiber connector 30A includes an optical fiber 2, a base portion 31A, and a holding portion 32, and includes a fiber holding member 33A that holds the optical fiber 2 sandwiched from above and below, and a cross-section U that fastens the base portion 31A and the holding portion 32 from above and below. And a clamp member 34 having a letter shape. The fiber holding member 33A is formed of the same material as the fiber holding member 7 in the first embodiment.

  The base portion 31 </ b> A is provided with a V-shaped or U-shaped stepped fiber groove 35 for positioning the optical fiber 2. The stepped fiber groove 35 has a coating deformation groove 36 formed at the front end of the base 31A, and a coating holding groove 37 formed on the rear end side of the base 31 with respect to the coating deformation groove 36. is doing. The configuration of the coating deformation groove 36 and the coating holding groove 37 is the same as that of the coating deformation groove 10 and the coating holding groove 11 in the first embodiment. A tapered portion 38 is provided between the coating deformation groove 36 and the coating holding groove 37. A pair of guide pins 39 is provided on the front end surface of the base 31A (see FIG. 12).

  A covering pressing groove 40 having a rectangular cross section is formed in a portion of the pressing portion 32 corresponding to the covering holding groove portion 37. That is, the pressing surface 32 a that presses the optical fiber 2 from above in the pressing portion 32 has a step shape corresponding to the stepped fiber groove 35. The pressing surface 32 a has a tapered portion 41 corresponding to the tapered portion 38 of the stepped fiber groove 9.

  In such a fiber holding member 33A, the covering deformation groove portion 36 of the base portion 31A and the portion corresponding to the covering deformation groove portion 36 in the pressing surface 32a of the pressing portion 32 are when the pressing portion 32 is pressed against the base portion 31A. In addition, a tip coating positioning portion 42 is configured to position the coating portion 4 formed at the tip portion of the optical fiber 2 by compressing and deforming the coating portion 4 along the coating deformation groove portion 36.

  The optical fiber 2 is introduced into the stepped fiber groove 35 from the rear end side of the fiber holding member 33A and is held by the fiber holding member 33A. The front end surface of the optical fiber 2 may be flush with the front end surface of the fiber holding member 33, or may slightly protrude from the front end surface of the fiber holding member 33 as shown in the figure.

  At this time, the covering portion 4 formed at the distal end portion of the optical fiber 2 is compressed and deformed into a substantially triangular shape along the covering deformation groove portion 36. Thereby, similarly to the above-described embodiment, even when the thickness variation of the coating portion 4 of the optical fiber 2 is large, the absolute value of the thickness variation of the coating portion 4 becomes small at the tip portion of the optical fiber 2, and the coating portion 4, the bare fiber glass portion 3 is guided and positioned along the coating deformation groove portion 36.

  The optical fiber connector 30B includes an optical fiber 2, a base portion 31B, and a pressing portion 32, a fiber holding member 33B that holds the optical fiber 2 sandwiched from above and below, and a clamp member that tightens the base portion 31B and the pressing portion 32 from above and below. 34. A pair of guide holes 43 into which the guide pins 39 of the optical fiber connector 30A are inserted is provided in the front end side portion of the base 31B (see FIG. 13). Other configurations of the base 31B are the same as the base 31A of the optical fiber connector 30A. The guide hole 43 is formed at a position where the stepped fiber grooves 35 of the base portions 31A and 31B are aligned with each other when the optical fiber connectors 30A and 30B are coupled to each other by inserting the guide pin 39. .

  When the optical fibers 2 are connected to each other using such optical fiber connectors 30A and 30B, the guide pin 39 of the optical fiber connector 30A is inserted into the guide hole 43 of the optical fiber connector 30B, and the optical fiber is connected. The connectors 30A and 30B are coupled together. At this time, the covering portion 4 at the tip of each optical fiber 2 held by the fiber holding members 33A and 33B is positioned in a state of being compressed and deformed by the tip covering positioning portion. Thereby, since the axial shift | offset | difference of each bare fiber glass part 3 of the optical fiber 2 which opposes is reduced similarly to embodiment mentioned above, the connection loss of the optical fiber 2 can be reduced.

  In this embodiment, the tip coating positioning portion 42 is formed at the front end of the fiber holding members 33A and 33B. However, the tip coating positioning portion 42 is formed in the entire longitudinal direction of the fiber holding members 33A and 33B. Also good. In this case, since the fiber grooves 35 of the base portions 31A and 31B and the pressing surface 32a of the pressing portion 32 do not need to be stepped, the fiber holding members 33A and 33B can be easily manufactured.

  In the present embodiment, the fiber holding members 33A and 33B are configured by the base portions 31A and 31B and the pressing portion 32. However, the present invention is not limited to this, and may have, for example, a collet chuck structure.

  FIG. 14 is a cross-sectional view showing a fourth embodiment of an optical fiber connector according to the present invention. In the drawing, the same reference numerals are given to the same or equivalent members as those of the above-described embodiment, and the description thereof is omitted.

  In the figure, an optical fiber connector 50 of the present embodiment is an outer diameter axis reference type optical fiber connector. The optical fiber connector 50 includes the optical fiber 2 and a cylindrical fiber holding member 51 that holds the optical fiber. The fiber holding member 51 is provided with a fiber hole 52 having a circular cross section for positioning and holding the optical fiber 2.

  The fiber hole 52 forms a tapered portion having a diameter that increases from the front end to the rear end of the fiber holding member 51. The diameter of the fiber hole 52 at the front end of the fiber holding member 51 is larger than the outer diameter of the bare fiber glass portion 3 of the optical fiber 2 and smaller than the outer diameter of the covering portion 4. The diameter of the fiber hole 52 at the rear end of the fiber holding member 51 is larger than the outer diameter of the coating portion 4 of the optical fiber 2. A part of the fiber hole 52 (a part having a diameter smaller than the outer diameter of the covering part 4) is provided with a tip covering positioning part 53 for compressing and positioning the covering part 4 formed at the tip part of the optical fiber 2. It is composed. Needless to say, the tip covering positioning portion 53 is provided at the front end portion of the fiber holding member 51.

  The optical fiber 2 is inserted into the fiber hole 52 from the rear end side of the fiber holding member 51 and is held by the fiber holding member 51. The front end surface of the optical fiber 2 may be flush with the front end surface of the fiber holding member 51, or may slightly protrude from the front end surface of the fiber holding member 51 as illustrated.

  At this time, the covering portion 4 formed at the distal end portion of the optical fiber 2 is compressed and deformed along the fiber hole 52 in the distal end covering positioning portion 53 of the fiber holding member 51. Thereby, similarly to the above-described embodiment, even when the thickness variation of the coating portion 4 of the optical fiber 2 is large, the absolute value of the thickness variation of the coating portion 4 becomes small at the tip portion of the optical fiber 2, and the coating portion 4, the bare fiber glass portion 3 is guided and positioned along the fiber hole 52.

  When two optical fiber connectors 50 are used to connect the optical fibers 2 to each other, a sleeve 54 having an inner diameter equivalent to the outer diameter of the fiber holding member 51 is prepared. Then, the two optical fiber connectors 50 are introduced into the sleeve 54 from both ends of the sleeve 54, and the front end surfaces of the optical fiber connectors 50 are butted together. By using the sleeve 54 as described above, the optical fiber connectors 50 can be positioned with a simple structure and with high accuracy.

  At this time, all of the covering portions 4 at the distal end portions of the optical fibers 2 held by the fiber holding member 51 are positioned in a state of being compressed and deformed by the distal end covering positioning portion 54. Thereby, since the axial shift | offset | difference of each bare fiber glass part 3 of the optical fiber 2 which opposes is reduced similarly to embodiment mentioned above, the connection loss of the optical fiber 2 can be reduced.

  Although several preferred embodiments of the optical fiber connector according to the present invention have been described above, the present invention is not limited to the above embodiments.

  For example, as a means for compressing and deforming the covering portion 4 of the optical fiber 2, as shown in FIG. 15, a plurality of directions can be applied to the covering portion 4 of the optical fiber 2 using a plurality of pressing portions 60, as shown in FIG. The outer cover 4 may be compressed and deformed by applying an external force. Also, as shown in FIG. 16, a fiber groove 62 having a chamfer 62 a is formed in the base portion 61, and the optical fiber 2 is pushed into the fiber groove 62 by the holding portion 63, thereby breaking the coating portion 4 of the optical fiber 2. And may be compressed and deformed.

  Further, as an optical fiber connector type optical fiber connector, in addition to the third and fourth embodiments, the holding portion is provided on the base so as to expose a part of the optical fiber positioned in the fiber groove of the base. An optical fiber connector provided with a so-called split-split mechanical splice type fiber holding member and an optical fiber connector provided with a mechanical splice type fiber holding member having a portion engaging with a latch portion of a latched connector. Etc. can also be used.

  In the above embodiment, a pair of facing optical fibers 2 are butted and connected to each other. However, it goes without saying that the present invention can also be applied to a structure in which a plurality of pairs of optical fibers 2 are butted and connected. .

It is sectional drawing which shows 1st Embodiment of the optical fiber connector concerning this invention. It is the II-II sectional view taken on the line of FIG. It is the III-III sectional view taken on the line of FIG. It is sectional drawing which shows a mode that the coating | coated part of the optical fiber shown in FIG. 1 is compressively deformed. It is sectional drawing which shows a mode that the coating | coated part of the optical fiber shown in FIG. 1 is compressively deformed. It is a figure which shows the state from which the bare fiber glass part of an optical fiber is eccentric. It is a graph which shows the relationship between the axial shift | offset | difference of each bare fiber glass part of the optical fiber which opposes, and the connection loss of an optical fiber. It is sectional drawing which shows 2nd Embodiment of the optical fiber connector concerning this invention. It is a front view of the optical fiber connector shown in FIG. It is sectional drawing which shows a mode that the coating | coated part of the optical fiber shown in FIG. 8 compresses and deforms. It is sectional drawing which shows 3rd Embodiment of the optical fiber connector concerning this invention. It is a front view of one optical fiber connector shown in FIG. It is a front view of the other optical fiber connector shown in FIG. It is sectional drawing which shows 4th Embodiment of the optical fiber connector concerning this invention. It is sectional drawing which shows another means to compress-deform the coating | coated part of an optical fiber. It is sectional drawing which shows another means to compress-deform the coating | coated part of an optical fiber.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Optical fiber connector, 2 ... Optical fiber, 3 ... Bare fiber glass part (bare fiber part), 4 ... Coating | coated part, 5 ... Base part, 6 ... Holding part, 6a ... Pressing surface, 7 ... Fiber holding member, 9 DESCRIPTION OF SYMBOLS ... Fiber groove, 10 ... Covering deformation groove part, 11 ... Covering holding groove part, 13 ... Covering pressing groove, 15 ... End covering positioning part, 20 ... Optical fiber connector, 21 ... Fiber holding member, 22 ... Fiber hole, 24 ... tapered portion, 25 ... tip covering positioning portion, 30A, 30B ... optical fiber connector, 31A, 31B ... base, 32 ... pressing portion, 32a ... pressing surface, 33A, 33B ... fiber holding member, 35 ... fiber groove, 36: coating deformation groove portion, 37: coating holding groove portion, 40: coating pressing groove, 42 ... tip coating positioning portion, 50 ... optical fiber connector, 51 ... fiber holding member, 52 ... fiber hole, 5 ... tip cover positioning section.

Claims (9)

An optical fiber connector for connecting at least one pair of optical fibers formed by forming a covering portion around a bare fiber portion,
A fiber holding member that holds each optical fiber in a butted state;
An optical fiber connector, wherein the fiber holding member is provided with a distal end covering positioning portion for compressing and positioning the covering portion formed at the distal end portion of each optical fiber. The fiber holding member has a base portion provided with fiber grooves for positioning the optical fibers, and a pressing portion that presses the optical fibers arranged in the fiber grooves against the base portion,
2. The optical fiber connector according to claim 1, wherein the tip covering positioning portion is formed by the fiber groove and a pressing surface of the pressing portion. The fiber groove is provided so as to sandwich the covering deformation groove portion forming the tip covering positioning portion and the covering deformation groove portion, and the covering holding groove portion having a depth and width larger than the covering deformation groove portion. And
The optical fiber connector according to claim 2, wherein a coating pressing groove is provided in a portion of the pressing portion corresponding to the coating holding groove. The fiber holding member has a tapered portion whose diameter increases from the center side toward both end sides, and is provided with fiber holes for positioning and holding the optical fibers,
The portion including the part of the tapered portion in the fiber hole forms the tip coating positioning portion having a diameter smaller than the outer diameter of the coating portion of the optical fiber. The optical fiber connector described. An optical fiber connector for connecting at least one pair of optical fibers formed by forming a covering portion around a bare fiber portion,
A fiber holding member for holding the optical fiber;
An optical fiber connector, wherein the fiber holding member is provided with a distal end covering positioning portion for compressing and positioning the covering portion formed at the distal end portion of the optical fiber. The fiber holding member has a base portion provided with a fiber groove for positioning the optical fiber, and a pressing portion that presses the optical fiber disposed in the fiber groove against the base portion,
6. The optical fiber connector according to claim 5, wherein the tip covering positioning portion is formed by the fiber groove and a pressing surface of the pressing portion. The fiber groove is provided at one end of the fiber holding member, and is provided on the other end side of the fiber holding member with respect to the coating deformation groove that forms the tip coating positioning portion, and the coating deformation groove. A covering holding groove having a depth and width larger than the covering deformation groove,
The optical fiber connector according to claim 6, wherein a coating pressing groove is provided in a portion of the pressing portion corresponding to the coating holding groove. The fiber holding member has a tapered portion whose diameter increases from one end side to the other end side, and is provided with a fiber hole for positioning and holding each optical fiber,
The portion including the part of the tapered portion in the fiber hole forms the tip coating positioning portion having a diameter smaller than the outer diameter of the coating portion of the optical fiber. The optical fiber connector described.   The optical fiber connector according to any one of claims 5 to 8, wherein the bare fiber portion protrudes from the end face of the covering portion by 10 to 1000 nm.

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