JP5411079B2 - Optical connector plug - Google Patents

Description

  The present invention relates to a plug that forms an optical connector with a connection member in which a plurality of connection holes are formed in an aligned state, and holds a plurality of optical fibers inserted into the connection holes of the connection member in an aligned state.

There is an increasing demand for various services using networks such as digital terrestrial broadcasting and on-demand distribution of high-quality content such as music or video. Accordingly, IP, such as the Internet and next generation networks (I nternet P rotocol) based network construction proceeds, is progressing capacity of information transmission. In parallel with this, an optical network using an optical fiber as a transmission path is rapidly developed from the viewpoint of the physical layer. For example, an advanced and large-capacity optical transmission system based on a wavelength multiplexing system has been introduced in a backbone or metro optical network. PON (P assive O ptical N etwork ) light of line using the method have been rapidly also in the access system. Furthermore, in various optical signal processing device such as a ROADM (r econfigurable o ptical a dd / d rop m ultiplexer) in an optical network, with the sophistication and scale of the signal processing device inside (between boards or in boards) As a result, the complexity of optical fiber wiring and the number of channels (number of optical fibers) have increased.

  On the other hand, high-end routers, high-end servers, large computers, and the like in IP networks are also required to perform large-scale and ultra-high-speed information processing. One key to achieve this is the realization of ultra-high-speed data transmission within and between devices, and the introduction of optical interconnection is proceeding instead of transmission using conventional electrical wiring. Along with this, in recent years, large-scale optical fiber wiring has been mounted on the information processing apparatus.

  Against this background, in the manufacture of optical communication devices and information processing devices, it is possible to improve the workability of mounting optical fiber wiring in the device, or to make the optical fiber wiring compact by improving the geometric layout of the optical fiber wiring. It has been demanded.

  Up to now, the means to mount optical fiber wiring while connecting optical fibers using the fusion splicing method has been used, so there is an extra length in the optical fiber, and it takes time and space to accommodate it in the device It is. However, when the means for mounting the optical fiber wiring is used while connecting the optical fiber using an optical connector instead of this, the extra length of the optical fiber becomes unnecessary, so that the above requirement can be met. From this point of view, there is an increasing demand for multi-fiber optical connectors that connect a plurality of optical fibers in a lump.

  The performance required for the multi-fiber optical connector used for mounting such an optical fiber wiring is particularly preferably a low connection loss and a high return loss. Furthermore, it is desired to be small, low cost and highly reliable. Multi-fiber optical connectors not only connect multiple optical fibers together, but also connect optical components based on optical waveguides, optical components such as semiconductor lasers and photodiodes, and optical fibers. What you do is also eligible.

As a promising multi-fiber optical connector that is highly likely to satisfy the requirements for the multi-fiber optical connector as described above, a multi-fiber optical connector that does not use a ferrule as disclosed in Patent Document 1 is known. . The optical connector includes a connection member having a connection portion in which a plurality of connection holes are formed in an aligned state, and a pair of members that are removably fitted to the connection member and hold a plurality of optical fibers in an aligned state. It has a plug. When connecting the optical fibers held by the pair of plugs, the pair of plugs are fitted to the connecting members from the opposite directions, and the tip portions of the optical fibers held by the plugs are formed at the connecting portions of the connecting members. Insert from both sides of the connection hole. Then, to buckle the optical fibers held in one of the plug, to the elastic force by utilizing both mutually PC connection end face of the optical fiber of the plug (P hysical C ontact) state.

JP 2008-216279 A

  FIG. 14 shows the planar shape of the plug of the optical connector described in Patent Document 1, and FIG. 15 shows the front shape thereof. The plurality of optical fibers 20 are held in an aligned state by a holding portion 32 provided in the housing 31 of the plug 30, and the distal end portion 21 b of the connection end portion 21 of the optical fiber 20 protruding from the holding portion 32 is a covering portion. The strand 20a is exposed by removing the covering layer 21a. As can be understood from FIGS. 14 and 15, since the connection end 21 of the optical fiber 20 is in a cantilever state, the tip end 21 b can be freely displaced to some extent. Usually, it is in a state of being separated from the aligned state. More specifically, the distal end portion 21b of the optical fiber 20 is slightly expanded in the alignment direction (left and right direction in FIG. 15). Also, the position of the tip 21b of each optical fiber 20 varies slightly in the vertical direction (vertical direction in FIG. 15) perpendicular to the alignment direction.

FIG. 16 schematically shows the relationship between the tip 21b of the connection end 21 of the optical fiber 20 of the plug 30 and the connection hole 42 of the connection 41 of the connection member 40 in such a state. A front shape of the hole 42 is shown in FIG. Here, the amount of positional deviation between the center axis 20C of the optical fiber 20 and the center axis 42C of the connection hole 42 immediately before the tip 21b of the optical fiber 20 is inserted into the connection hole 42 of the connection part 41 of the connection member 40 is represented by ΔE. Show. Also shown (in FIG. 17, the left-right direction) alignment direction of the optical fiber 20 lateral displacement amount a Delta] E _X along, (in FIG. 17, the vertical direction) orthogonal direction to the arrangement direction the amount of longitudinally displaced in Delta] E _Y .

When the strand 20a of the tip portion 21b of the optical fiber 20 is inserted into the connection hole 42, the optical fiber 20 cannot be inserted into the connection hole 42 if the positional deviation amount ΔE exceeds an allowable range. If even one of the optical fibers 20 in the plug 30 has a positional deviation exceeding an allowable range, the optical fiber 20 cannot be inserted into the connection hole 42, and the plug 30 cannot be attached to the connection member 40. Thus, the other optical fiber 20 cannot be inserted. That is, the connection operation as an optical connector is not established. If the plug 30 is forcibly pushed into the connecting member 40 in a state where a certain optical fiber 20 cannot be inserted, the optical fiber 20 that cannot be inserted is broken with a high probability. That is, the optical connector is in a failure state. For example, the outer diameter D _t of the connection end face 22 of the strand 20a chamfered at the tip 21b is 70 μm for the coated portion 21a, that is, the optical fiber 20 whose outer diameter of the coating layer is 250 μm and the diameter of the strand 20a is 125 μm. When the diameter D _m of the conical guide portion 42a formed at the opening end of the connection hole 42 is 400 μm, the vertical deviation amount ΔE _X is allowed to be up to about 165 μm and the lateral deviation amount ΔE _Y is allowed to be about 90 μm. The Since the distance between the centers of the adjacent connection holes 42 is set to about 250 μm, even if the diameter D _m of the guide portion 42 a is increased, the allowable value of the lateral shift amount ΔE _Y cannot be made larger than about 90 μm.

When the optical fiber 20 is inserted into the connection hole 42, the relative misalignment is mainly caused by the following two reasons. That is, one is a positional deviation amount ΔE _C caused by a manufacturing tolerance of the plug 30 and the connecting member 40 and a fitting tolerance when the plug 30 and the connecting member 40 are fitted. The other is a positional deviation amount ΔE _P of the distal end portion 21b of the connection end portion 21 of the optical fiber 20 with respect to the housing 31 of the plug 30 in a cantilever state.

The positional deviation amount ΔE _C caused by the former dimensional tolerance and fitting tolerance can be reduced to 40 μm or less by realizing a high molding accuracy of the plug 30 and the connecting member 40 and a clearance fitting accuracy of 15 μm or less. It is possible.

On the other hand, regarding the positional deviation amount ΔE _P of the connection end 21 of the latter optical fiber 20 due to the cantilever support, it is necessary to secure the length of the connection end 21 about 7 mm in order to realize the PC connection. In order to realize high-density mounting, it is necessary to narrow the interval between adjacent optical fibers 20 to about 250 μm. For this reason, it is inevitable that the distal end portion 21b of the connection end portion 21 of the optical fiber 20 held by the plug 30 is scattered as shown in FIGS. The positional deviation amount ΔE _P may exceed 50 μm. As a result, there is a possibility that the final vertical deviation amount ΔE _Y may exceed 90 μm together with the previous positional deviation amount ΔE _C, and the connection as an optical connector will not be established.

  Such a problem is caused by connecting not only the pair of plugs 30 that perform PC connection but also the plug 30 and a connection member in which an optical component such as a semiconductor laser, a photodiode, or an optical waveguide is attached to one end of the connection hole 42. The same occurs in the optical connector.

  The present invention has been made in view of the above-described problems in a conventional multi-fiber optical connector, and is a plug for an optical connector capable of correcting the variation in the position of the distal end of the connection end of an optical fiber caused by a cantilever state. The purpose is to provide.

  The present invention is a plug that is fitted to a connecting member in which a plurality of connecting holes are aligned and constitutes an optical connector with the connecting member, and the plug includes a holding portion that holds a plurality of optical fibers in an aligned state. A connecting end portion of the plurality of optical fibers protruding from the holding portion of the housing, a covering portion including a covering layer covering the strands of the optical fibers, and a tip portion from which the covering layer is removed These tip portions are connected end portions of the plurality of optical fibers in plugs respectively inserted into the connection holes of the connection member in accordance with the fitting operation of the plug to the connection member. An alignment member that is provided on the covering portion and holds the tip ends of the connection end portions of the plurality of optical fibers in an aligned state. Is characterized in that it is non-contact with said housing with arranged close to the distal end side of the connecting end portions of the plurality of optical fibers than.

  In the present invention, an alignment member is provided at the connecting end portion of the optical fiber that protrudes from the holding portion of the plug and is in a cantilever state. The presence of the alignment member corrects the strands at the distal end portion.

  In the present invention, the connection end portion of the optical fiber refers to a region protruding from the holding portion of the plug to the connection hole side of the connection member. In addition, the distal end portion of the connection end portion is a region that is inserted into a plurality of connection holes of the connection member, and indicates a region from which the optical fiber coating layer has been removed. Accordingly, although the strand is exposed at the tip of the optical fiber, the strand in the present invention has some coating layer such as a metal thin film layer that is not removed by a general coating removal operation on the surface. Also included. Further, the covering portion refers to a region other than the tip portion, that is, a region where a strand is covered with a covering layer.

  The optical connector is an optical connector in which the connection end portions of the plurality of optical fibers are buckled in the fitted state of the plug and the connection member according to the present invention, and the alignment member along the longitudinal direction of the connection end portions of the plurality of optical fibers. The length is preferably 0.5 mm or more and 1.5 mm or less.

  The alignment member has a frame shape with a rectangular opening surrounding the connection ends of a plurality of optical fibers, or an opening corresponding to the cross-sectional shape of the connection ends of the plurality of optical fibers in an aligned state. It may be a frame having a part. In any case, it is preferable that the opening has an enlarged diameter portion at one opening end thereof.

  Alternatively, the alignment member may be an adhesive that is bonded to the connection ends of a plurality of optical fibers. In this case, the alignment member preferably has an elastic coefficient of 10 MPa or less.

  According to the present invention, since the alignment member holds the connection end portions of a plurality of optical fibers in an aligned state, the positional accuracy of the strands at the tip end portions of the connection end portions of the optical fibers can be improved as compared with the conventional plug. . As a result, the plug can be reliably connected to the connection member of the optical connector, and the reliability of the connection operation can be improved. In addition, since the alignment member is not in contact with the housing, it does not hinder the free displacement of the connection end of the optical fiber when the tip is fitted into the connection hole of the connection member. As a result, no harmful stress is generated at the connection end of the optical fiber during connection, and the plug can be smoothly connected to the connection member.

  The optical connector is an optical connector in which the connection end of a plurality of optical fibers is buckled when the plug and the connection member are fitted, and the length of the alignment member along the longitudinal direction of the connection end of the optical fiber is 0.5 mm or more. When the thickness is set to 1.5 mm or less, the plug is fitted to the connecting member constituting the optical connector together with the plug, and the presence of the alignment member reduces the degree of hindrance to the bending due to the buckling of the connecting end of the optical fiber. can do. That is, the PC state of the connection end face of the optical fiber can be realized as smoothly as when no alignment member is present.

It is a top view showing the appearance of one embodiment of the optical connector by the present invention in the fracture state, and represents the state in the middle of connection. It is sectional drawing showing the arrow shape along the II-II line | wire in FIG. FIG. 3 is a cross-sectional view illustrating an arrow shape along line III-III in FIG. 2. It is sectional drawing showing the arrow view shape along the IV-IV line in FIG. It is a front view of the plug in embodiment shown in FIG. FIG. 6 is a three-dimensional projection view showing the appearance of the alignment member in the plug shown in FIG. FIG. 2 is a plan view illustrating a connection state in the embodiment illustrated in FIG. 1. It is sectional drawing showing the arrow shape along the VIII-VIII line in FIG. FIG. 2 is a partially extracted enlarged plan view for explaining a problem when the alignment member is brought into contact with the housing of the plug in the embodiment shown in FIG. 1. It is a front view of the plug showing other embodiment of an alignment member. It is a three-dimensional projection figure showing the external appearance of the alignment member in embodiment shown in FIG. 10 in the fracture | rupture state. It is a front view of the plug showing another embodiment of an alignment member. It is a top view showing the appearance of other embodiments of the optical connector by the present invention in the fracture state. It is a top view which represents typically the external appearance of the plug in the conventional optical connector. It is a front view of the plug shown in FIG. It is a conceptual diagram which represents typically the position of the connection part of the connection member of an optical connector, and the front-end | tip part of the connection end part of an optical fiber. It is a front view of the connection part of the connection member in FIG.

  INDUSTRIAL APPLICABILITY The present invention is suitable for application to an optical connector for connecting an optical fiber and an optical component or another optical fiber in an optical signal processing apparatus in an optical network or an information processing apparatus having a high-speed data transmission system using optical interconnection. Is. An embodiment of an optical connector according to the present invention will be described in detail with reference to FIGS. However, the present invention is not limited to these embodiments, and can be applied to any form of optical connector belonging to the spirit of the present invention.

  FIG. 1 is a partially cutaway plan view of the optical connector in the first embodiment, and FIG. 2 shows the cross-sectional shape along the line II-II. The lines III-III and IV-IV are shown in FIG. 3 and 4 show cross-sectional shapes taken along the arrows. Further, the front shape of one plug is shown in FIG. 5, the appearance of the alignment member is partially broken and shown in FIG. 6, and the planar shape of the connection state of this optical connector is shown in FIG. FIG. 8 shows a cross-sectional shape taken along the arrow.

  The optical connector 10 according to this embodiment includes a pair of plugs 30F and 30S each holding a plurality of optical fibers 20, and an adapter 40 into which the pair of plugs 30F and 30S are detachably fitted. The The optical connector 10 further includes a clamp member for maintaining the connection state between the pair of plugs 30F, 30S and the adapter 40 by a spring force or the like. In addition, the clamp member is illustrated for clarifying the invention part. Note that not. By connecting the pair of plugs 30F and 30S through the adapter 40, the optical connection of the optical fiber 20 held by the pair of plugs 30F and 30S is achieved. The optical connector 10 in the present embodiment is for optically connecting eight cores, that is, eight optical fibers 20 to each other in a PC state.

  The housings 31F and 31S of the plugs 30F and 30S respectively have holding portions 32 for holding the connection end portion 21 of the optical fiber 20 in an aligned state. Here, the aligned state refers to a state in which the connection end portions 21 of the optical fibers 20 are arranged at predetermined intervals that are set in advance and their central axes are parallel to each other. The holding portion 32 in the present embodiment includes a plurality of grooves 32a formed in the housings 31F and 31S and arranged in parallel at predetermined intervals, a pressing plate 32b, and a pair of spring clips 32c. The individual grooves 32a have a V-shaped cross section and are arranged in parallel to each other at intervals of 250 μm, which is the same as the outer diameter of the coating portion 21a of the optical fiber 20, that is, the coating layer. The holding plate 32b pushes the optical fiber 20 between the grooves 32a of the housings 31F and 31S by the spring force of the pair of spring clips 32c, and aligns them using friction generated between the covering portions 21a. Hold on.

The optical fiber 20 held by each plug 30F, 30S is a quartz optical fiber, but is not limited to this. Only the front end portion 21b of the connection end portion 21 is in a state in which the covering layer is removed and the strand 20a, that is, the clad is exposed. In this embodiment, the outer diameter of the strand 20a of the optical fiber 20 is about 125 μm, and the outer diameter of the coating layer is about 250 μm. The arrangement interval of the optical fibers 20 having an interval of about 250 μm is the same as the arrangement interval of the optical fibers in a general ribbon (tape) type multi-core optical fiber. The arrangement interval of the connection holes 42 of the connection portion 41 of the adapter 40 described later is also set to be the same. The connection end surface 22 of the optical fiber 20 is processed into a flat mirror surface orthogonal to the central axis 20C. Further, the peripheral edge of the connection end surface 22 is processed into a conical shape to form a chamfered portion 22a, and the diameter of the connection end surface 22 is smaller than 125 μm (for example, 70 μm). To the PC status at the time of connection, (in FIG. 1, left) one of the plug 30F tip of the optical fiber 20 in it is slightly protrude by ΔL than the abutting faces 31F _E of the housing 31F. (In FIG. 1, right side) the other plug 30S tip of the optical fiber 20 in is located substantially flush with abutting face 31S _E of the housing 31S. Therefore, the length of the connection end 21 of the optical fiber 20 in the plug 30F is set longer than that of the plug 30S.

  In addition, the front-end | tip part 21b defined by this specification is interpreted as an area | region including the strand 20a of the optical fiber 20 which remain | survives by removing a coating layer. Therefore, even if the strand 20a located at the tip 21b is completely exposed to the outside, or is covered with some coating layer (for example, a metal thin film layer) that is not removed by a normal coating removal process. It should be noted that such a case is included in the present invention.

  The alignment member 50 that holds the connection end portion 21 of the optical fiber 20 in an aligned state is for aligning the relative position of the tip end portion 21b of the optical fiber 20 held by the plugs 30F and 30S with the designed relative position. It is. The attachment position of the alignment member 50 with respect to the optical fiber 20 is the covering portion 21a of the connection end portion 21 excluding the distal end portion 21b of the optical fiber 20, and when the plugs 30F and 30S are attached to the adapter 40, the connection portion of the adapter 40 41 is a position that does not contact 41. However, in order to enhance the alignment effect, it is necessary to dispose it closer to the distal end portion 21b side of the connection end portion 21 than the holding portion 32, and it is desirable to be as close to the distal end portion 21b of the optical fiber 20 as possible. From such a viewpoint, in this embodiment, the alignment member 50 is disposed at a position approximately 1 mm away from the boundary between the tip portion 21b and the covering portion 21a toward the holding portion 32 side.

  The alignment member 50 in the present embodiment has a frame shape having a substantially rectangular opening 51, and is attached to the optical fibers 20 with eight optical fibers 20 passing through the openings 51. The size and shape of the opening 51 correspond to the relative position of the optical fiber 20 held by the holding portions 32 of the housings 31F and 31S of the plugs 30F and 30S. That is, the width W along the horizontal direction (left and right direction in FIG. 5) of the opening 51 is about 2 mm (250 μm × 8), and the height H along the vertical direction (vertical direction in FIG. 5) is It is set to about 250 μm. In addition, regarding the height H in the vertical direction, it is possible to set this to about 260 μm so as to make a clearance fit to the covering portion 21 a of the connection end 21 of the optical fiber 20, but conversely to about 245 μm. It can also be set to a tight fit state. That is, if the fitting accuracy is within this range, sufficient alignment accuracy of the tip portion 21b of the optical fiber 20 can be obtained when the optical fiber 20 is smoothly inserted into the connection hole 42, and the optical fiber 20 is surrounded by the alignment member 50. This is because these relative positional displacements along the longitudinal direction of the optical fiber 20 in the portion are allowed. The reason why the relative displacement in the longitudinal direction of the optical fiber 20 is allowed even in the case of tight fitting is that the material constituting the covering layer of the covering portion 21a has flexibility. That is, when the plugs 30F and 30S are fitted to the adapter 40 for connection, the covering portion 21a is deformed to allow the longitudinal position of the optical fiber 20 to be displaced.

  Usually, the alignment member 50 is made of a relatively lightweight resin, and therefore, in the case of an interference fit, the alignment member 50 is held at a predetermined position of the optical fiber 20 by friction with the covering portion 21a of the connection end portion 21 of the optical fiber 20. On the other hand, in the case of clearance fitting, a sealing silicone resin having a relatively low elastic modulus after curing is applied between the opening 51 of the alignment member 50 and the covering portion 21 a of the connection end 21 of the optical fiber 20. A part of the formed gap is filled, and the connection end portion 21 of the optical fiber 20 is held at an appropriate position with respect to the alignment member 50.

  The outer dimension of the alignment member 50 is defined so as not to contact the housings 31F and 31S of the plugs 30F and 30S and the adapter 40, that is, to contact only the covering portion 21a of the connection end 21 of the optical fiber 20. . The alignment member 50 corrects the position of the distal end portion 21b of the optical fiber 20, but is supported by the connection end portion 21 of the optical fiber 20, and therefore follows the displacement of the connection end portion 21 of the optical fiber 20. Displacement integrally with.

  A chamfered enlarged diameter portion 51 a is formed at one opening end of the opening 51 of the alignment member 50. Thereby, the operation | work which mounts the alignment member 50 to the optical fiber 20 can be made easy. When this alignment member 50 is passed through the tip 21b of the connection end 21 of the optical fiber 20 and attached to the portion of the coating layer 21 of the connection end 21 close to the tip 21b, the tips 21b of the eight optical fibers 20 are According to the size and shape of the openings 51, they are aligned at intervals of approximately 250 μm. That is, the tip end portions 21b of the connection end portions 21 of the eight optical fibers 20 are almost corrected to the designed arrangement interval. In this case, since the alignment member 50 is not in contact with the housings 31F and 31S of the plugs 30F and 30S, the position of the tip 21b of the optical fiber 20 with respect to the housings 31F and 31S of the plugs 30F and 30S is designed. It is not always in position. In other words, the alignment member 50 does not guarantee that the positional deviation amount of the distal end portion 21b of the optical fiber 20 is substantially zero. However, this alignment member 50 can reduce the variation in the amount of positional deviation of the distal end portion 21b of each optical fiber 20, and as a result, the reliability at the time of connection with the adapter 40 can be improved.

  It should be noted that the alignment along the horizontal direction (left and right direction in FIG. 5) of the tip portion 21b of the optical fiber 20 is allowed to be slightly inclined with the alignment member 50. In this state, the horizontal arrangement state of the optical fibers 20 held by the holding portions 32 of the housings 31F and 31S and the horizontal arrangement state of the optical fibers 20 surrounded by the alignment member 50 are not parallel. However, since the distal end portion 21 b of the optical fiber 20 is corrected to be parallel to each other by the alignment member 50, the variation in the total amount of deviation from the design relative position is more than that of the conventional one without the alignment member 50. It will be suppressed. Since the coating layer 21 of the optical fiber 20 is easily deformed by an external force, if the length of the opening 51 of the alignment member 50 along the longitudinal direction of the optical fiber 20 is short, the correction effect on the optical fiber 20 is reduced. The longer the length of the opening 51 of the alignment member 50, the greater the effect of aligning the tip 21b of the optical fiber 20 in parallel.

  The reason why the alignment member 50 is not brought into contact with the housings 31F and 31S and the adapter 40 is that the buckling of the optical fiber 20 is not adversely affected. In addition, secondly, the degree of freedom of the connection end 21 of the optical fiber 20 is ensured at the time of connection, and the insertion operation of the tip end 21b of the optical fiber 20 into the connection hole 42 is facilitated.

  For example, as shown in FIG. 9, when the longitudinal ends 50 a of the alignment member 50 are configured to contact the housing 31 of the plug 30, the following problems occur. That is, in FIG. 9, the displacement of the connection end 21 of the optical fiber 20 along the vertical direction perpendicular to the paper surface is enabled by sliding contact between the longitudinal ends 50a of the alignment member 50 with respect to the housing 31 of the plug 30. There is almost no negative effect on directional buckling. However, since the displacement in the lateral direction is regulated by the alignment member 50, the connection end portion 21 of the optical fiber 20 located between the holding portion 32 of the housing 31 and the alignment member 50 cannot be bent. As a result, only the connection end 21 of the optical fiber 20 protruding from the alignment member 50 can be displaced. That is, the lateral displacement between the center axis 20C of the optical fiber 20 and the center axis 42C of the connection hole 42 due to the manufacturing tolerance and fitting tolerance of these components is the connection end of the optical fiber 20 protruding from the alignment member 50. It is absorbed only by 21 deformations. In particular, since the distance between the connection hole 42 and the alignment member 50 is close in the connected state, a strong bending force acts on the connection end 21 of the optical fiber 20 interposed therebetween, resulting in an increase in transmission loss that cannot be ignored. In the worst case, the optical fiber 20 may be damaged. By setting the alignment member 50 in a non-contact state with respect to the housing 31 and the adapter 40 of the plug 30, it is possible to reliably avoid such a problem.

  The alignment member 50 is preferably manufactured by injection molding using a resin. Since the specific gravity of resin is generally smaller than that of metal or the like, an adverse effect due to the weight of the alignment member 50, that is, an increase in the amount of stagnation of the distal end portion 21 b of the optical fiber 20 can be suppressed. Moreover, when it is necessary to manufacture the alignment member 50 in large quantities, it can be manufactured at low cost by adopting an injection molding method.

When the alignment member 50 is attached to the optical fiber 20, the alignment member 50 is fitted to the optical fiber 20 by the frictional force with the coating layer 21 of the optical fiber 20. However, it can be fixed to the optical fiber 20 with an adhesive having a relatively small elastic modulus. This is to allow the alignment member 50 and the optical fiber 20 to move slightly relative to each other along the longitudinal direction of the optical fiber 20. When the plugs 30F and 30S are not attached to the adapter 40, the protrusion length ΔL of the distal end portion 21b of the optical fiber 20 from the abutting surfaces 31F _E and 31S _E of the housings 31F and 31S of the plugs 30F and 30S Is not exactly the same regarding. For this reason, when the plurality of optical fibers 20 held by the pair of plugs 30F and 30S are set to the PC state, a slight relative movement along the longitudinal direction of the individual optical fibers 20 held by the plugs 30F and 30S is allowed. There is a need.

  The adapter 40 as a connecting member in the present invention has a connecting portion 41 formed with eight connecting holes 42 into which the distal end portion 21b of the optical fiber 20 held by the plugs 30F and 30S is removably inserted. Have. The connection holes 42 are formed in parallel with each other at an interval of 250 μm, and each connection hole 42 has a conical guide part 42a formed so as to face the opening end surface, and a coating layer insertion part 42b subsequent thereto. And an alignment portion 42c into which the strand 20a of the tip portion 21b of the optical fiber 20 is inserted. A pair of guide portions 42 a and covering holding portions 32 are formed on both sides in the longitudinal direction of the connection hole 42. The guide part 42a has a conical shape whose diameter increases toward the opening end side of the connection hole 42. The coating holding portion 32 has an inner diameter that is substantially equal to the outer diameter of the coating layer 21 of the optical fiber 20. The aligning portion 42c has a slightly larger inner diameter than the diameter of the strand 20a. Although the structure of the connection portion 41 is similar to the ferrule of the MT connector, the adapter 40 can be manufactured at low cost because the positional accuracy of the connection hole as in the MT connector is not required.

  The housings 31F and 31S of the plugs 30F and 30S and the adapter 40 are obtained by molding a resin. The connection portion 41 of the adapter 40 can be formed by processing ceramics or glass and can be integrated when the adapter 40 is formed.

When connecting a pair of plugs 30F and 30S via the adapter 40, first, one of the plugs 30F and 30S, for example, the plug 30F is inserted into the adapter 40, and the distal end portion 21b of the optical fiber 20 is inserted into the connection hole 42. At this time, the center axis 20C of the optical fiber 20 and the center axis 42C of the connection hole 42 are usually slightly shifted. However, the connection end portion 2121 of the optical fiber 20 is elastic so that the chamfered portion 22a of the distal end portion 21b of the optical fiber 20 slides toward the center side of the connection hole 42 along the guide portion 42a at the opening end of the connection hole 42. It is displaced to. As a result, the distal end portion 21b of the optical fiber 20 can be smoothly guided to the connection hole 42. Further, since the position of the distal end portion 21b of the connection end portion 21 of the optical fiber 20 by the alignment member 50 is corrected, in particular small variations in the lateral deviation amount Delta] E _x and vertical deviation amounts Delta] E _Y (see FIG. 17) be able to. In addition, it is possible to eliminate the situation in which the plugs 30F and 30S cannot be connected to the adapter 40, or to significantly reduce the situation compared to the conventional one. That is, it is possible to smoothly insert the optical fiber 20 into the connection hole 42. Specifically, when the plug 30F is inserted into the adapter 40, the insertion resistance increases at the moment when the distal end portion 21b of the optical fiber 20 enters the connection hole 42, but the presence of the alignment member 50 makes this insertion resistance higher than the conventional one. Can be reduced.

Similarly, the remaining plug 30 </ b> S is inserted into the adapter 40, and the distal end portion 21 b of the optical fiber 20 is inserted into the connection hole 42. Then, inserting a pair of plug 30F, the 30S to the adapter 40 to the abutting surfaces 31S _E of the housing 31S of abutting surfaces 31F other plug 30S against _E of the housing 31F of one of the plug 30F abuts. Thereby, the connection end surfaces 22 of the pair of optical fibers 20 are in the PC state. As a result, the air gap between the connection end faces 22 disappears, and Fresnel reflection hardly occurs in the propagating light passing therethrough, and the generation of reflected return light becomes very small. That is, a high return loss is realized. The reason why the chamfered portion 22a is formed on the connection end surface 22 of the optical fiber 20 to reduce the area of the connection end surface 22 is to realize the PC state more reliably. Thus, since the optical connector 10 in this embodiment can connect a pair of plugs 30F and 30S in the PC state using the adapter 40, it is possible to maintain stable connection characteristics. In this state, the tip portion 21b of the optical fiber 20 of one plug 30F is retracted toward the holding portion 32 side of the housing 31F by the protrusion amount ΔL, and the connection end portion 21 of the optical fiber 20 is buckled and bent. On the other hand, it should be noted that the optical fiber 20 does not buckle in the other plug 30S because the length of the connection end 21 of the optical fiber 20 is shorter than that of the one plug 30F.

  In one plug 30F in the present embodiment, the length of the connection end portion 21 of the optical fiber 20 protruding from the holding portion 32 of the housing 31F of the plug 30F is set to about 7 mm. If the length of the alignment member 50 along the longitudinal direction of the optical fiber 20 is longer than about 1.5 mm, the portion of the optical fiber 20 held by the alignment member 50 cannot be curved so much. Therefore, the smooth buckling deformation of the optical fiber 20 is hindered at the time of connection, and there is a high possibility that the PC state cannot be realized. Conversely, when the length of the alignment member 50 is less than about 0.5 mm, it is difficult to handle the alignment member 50 when it is attached to the connection end 21 of the optical fiber 20. Moreover, the effect of aligning the optical fiber 20 while maintaining a non-contact state with respect to the housing 31F and the adapter 40 cannot be obtained due to strength problems. Therefore, the length of the alignment member 50 is preferably about 0.5 mm or more and about 1.5 mm or less. In this way, the adverse effect on the bending of the optical fiber 20 due to the mounting of the alignment member 50 is minimized.

When a high return loss is not required between the pair of plugs 30F and 30S, that is, when the PC state is not required, the optical fiber 20 from the butt surface 31F _E of the housing 31F is used as one plug 30F. It is also possible to use a plug in which the protruding amount of the front end portion 21b is set to almost zero, for example, the other plug 30S. In this case, since it is not necessary to buckle the connection end 21 of the optical fiber 20, the length can be shortened to about 5 mm.

  In this embodiment, the number of connection cores of the optical connector 10 is eight, but the present invention is not limited to this. For example, when plugs 30F and 30S that hold 16 optical fibers 20 at a pitch of 250 μm are used, an alignment member 50 having an opening 51 having a height H of 250 μm and a width W of about 4 mm (250 μm × 16) is employed. do it. Moreover, since the optical connector 10 in this embodiment does not generate so much internal stress as the optical fiber 20 is bent and deformed, it is possible to realize connection of several tens of optical fibers 20. Since the optical connector 10 according to the present embodiment does not use a ferrule, the manufacturing cost can be reduced accordingly.

  In the embodiment described above, the outline shape of the opening 51 of the alignment member 50 is set to be an elongated rectangle. However, the opening 51 having a shape along the outline of the coating layer 21 of the optical fiber 20 in the aligned state may be used. It is.

  The front shape of another embodiment of the plug 30 of the optical connector according to the present invention is shown in FIG. 10, and a part of the appearance of the alignment member 50 is broken and shown in FIG. These elements are given the same reference numerals, and redundant description is omitted. That is, the basic shape of the optical connector of this embodiment may be the same as that of the previous embodiment, and only the alignment member 50 is different. The alignment member 50 has an opening shape corresponding to a state in which eight optical fibers 20 having an outer diameter of the covering layer 21 of 250 μm are aligned at a pitch of 250 μm. More specifically, circular openings having an inner diameter slightly larger than 250 μm are formed at intervals of 250 μm so as to provide a clearance fit with the covering layer 21, and a part of the adjacent openings overlap to form a whole. Two openings 51 are defined. At one end in the longitudinal direction of the opening 51, a chamfered enlarged diameter portion 51a is formed to facilitate the operation when the connection end 21 of the optical fiber 20 is inserted. The alignment member 50 according to the present embodiment has a larger contact area with the coating layer 21 of the optical fiber 20 than the alignment member 50 according to the previous embodiment, and the deformation of the coating layer 21 can be reduced. The effect can be further enhanced.

  The shape of the opening 51 described above needs to match the alignment interval of the optical fibers 20 held by the plugs 30F and 30S. For example, when the four-core plugs 30F and 30S in which the above-described optical fiber 20 having a diameter of the coating layer 21 of 250 μm is aligned at intervals of 500 μm are used, the openings 51 formed in the alignment member 50 are independent of each other. 4 round holes. Further, these four round holes are arranged at intervals of 500 μm. In this case, it should be noted that the arrangement interval of all the optical fibers 20 held in the plug 30 in an aligned state is not the same, and the diameter of the coating layer 21 of the optical fiber 20 is not limited to 250 μm.

  Since the rubber-based resin having an elastic coefficient of about 10 MPa or less can be adopted as the alignment member 50, it is not a molded product of the resin as described above, but a material obtained by curing a resin such as an adhesive. Is possible.

  An example of a procedure for creating such an alignment member 50 will be described below. First, an alignment jig having the same shape as the alignment member 50 as shown in FIGS. 6 and 11 is created by machining. Next, this is inserted through the portion of the coating layer 21 adjacent to the tip 21b of the connection end 21 of the optical fiber 20 held by the plug 30, and the connection end 21 of the optical fiber 20 is held in an aligned state. Thereafter, a high-viscosity resin having some fluidity is applied to the portion of the coating layer 21 of the connection end 21 of the optical fiber 20 adjacent to the alignment jig and cured, and then the alignment jig is removed. The cured resin functions as the alignment member 50. The alignment member 50 is integrated with the connection end 21 of the optical fiber 20, but allows bending and buckling of the optical fiber 20 due to its viscoelasticity. The alignment member 50 has a drawback that it takes more time to mount the alignment member 50 on the optical fiber 20 than the alignment member 50 formed by molding in the previous embodiment. However, when the plug 30 is not a mass-produced product, the alignment form of the optical fiber 20 is special, or the dimensional shape is out of the standard, it is advantageous in terms of cost over the previous embodiment. I can say that.

  In the above-described embodiment, a plurality of optical fibers 20 are aligned in a line on the same plane, but it is also possible to align them in a plurality of lines.

  FIG. 12 shows the front shape of another embodiment of the plug 30 of the optical connector according to the present invention. Elements having the same functions as those of the previous embodiment are designated by the same reference numerals and are duplicated. The explanation will be omitted. That is, the plug 30 in this embodiment is a modification of the embodiment shown in FIG. 5, and is a 16-core type in which the optical fibers 20 aligned in the horizontal direction are arranged in two stages in the vertical direction. Similarly, the connection hole 42 of the connection part 41 of the connection member such as the adapter 40 in the previous embodiment is also formed in two stages so as to correspond to the arrangement state of the optical fibers 20 held by the plug 30. The alignment member 50 has an opening 51 having a size corresponding to the design arrangement of the 16 optical fibers 20, and more specifically, a rectangular opening for inserting the eight optical fibers 20 in an aligned state. Two 51 are provided on the upper and lower sides. Due to the presence of the alignment member 50, the positional deviation of the distal end portion 21b of the optical fiber 20 is corrected. It is also possible to make the opening 51 of the alignment member 50 have the same shape as the embodiment shown in FIGS.

  In the above-described embodiment, the optical connector 10 that connects the optical fiber 20 held by the pair of plugs 30F and 30S in the PC state has been described. However, the connection member on which an optical component other than the optical fiber is mounted is connected to the plug. It can also be applied to optical connectors.

  FIG. 13 shows a plan view of another embodiment of the optical connector according to the present invention. Elements having the same functions as those of the previous embodiment are designated by the same reference numerals, and redundant description is omitted. It shall be. That is, the optical connector 10 in the present embodiment is for connecting an optical component such as an optical transceiver module and a plurality of optical fibers 20 in a lump, and includes one plug 30 and a connection member in the present invention. The receptacle 60 forms a main part. The basic configuration of the receptacle 60 may be the same as that disclosed in International Publication No. 2008-096716. Further, the plug 30 in the present embodiment may be the same as the other plug 30S in the embodiment shown in FIG.

  The receptacle 60 has a connection portion 41, and a connection hole 42 into which the distal end portion 21 b of the optical fiber 20 held by the plug 30 is removably inserted is inserted into the connection portion 41 at the same interval as the alignment interval of the optical fibers 20. Is formed. An optical component 61 is arranged at the end of the connection hole 42 on the side opposite to the insertion / extraction side of the optical fiber 20 so as to be coaxial with the central axis 42 </ b> C of the connection hole 42. Examples of the optical component 61 include an optical waveguide in addition to a semiconductor laser and a photodiode.

Therefore, when the plug 30 that can be removed from the receptacle 60 is fitted into the receptacle 60, the tip 21 b of the connection end 21 of the optical fiber 20 held by the plug 30 is inserted into the connection hole 42 of the connection 41. . In this case, the forward end of the plug 30 relative to the receptacle 60 is regulated by the abutment surface 31 _E of the housing 31 of the plug 30 abutting against the alignment surface 62 of the receptacle 60, and the connection end surface 22 of the distal end portion 21 b of the optical fiber 20 is restricted. Opposite the optical component 61 in proximity. In this case, since it is not necessary to buckle the optical fiber 20 to make it the PC state with respect to the optical component 61, the other plug 30S in the previous embodiment can be used, and the alignment member 50 is connected to the tip of the optical fiber 20. It can be arranged closer to 21b.

  In the above, an example of an optical connector in which the number of optical fibers 20 and the arrangement form of the optical fibers 20 in the plug 30 are different has been described. However, generally speaking, the optical fibers 20 are in an aligned state. The position and the direction of the central axis line are arranged so as to coincide with the relative position and the direction of the central axis line in the design. Moreover, generally speaking, the opening 51 of the alignment member 50 is designed to have a shape corresponding to the arrangement of the aligned optical fibers 20.

  It should be noted that the present invention should be construed only from the matters described in the claims, and in the above-described embodiment, all the changes and modifications included in the concept of the present invention are other than those described. Is possible. That is, all matters in the above-described embodiment are not intended to limit the present invention, and include any configuration not directly related to the present invention. To get.

10 optical connectors 20 optical fiber 20a strands 20C fiber central axis 21 connecting end portion 21a covering portion 21b distal end portion 22 connecting end face 22a chamfer 30,30F, 30S plug 31,31F, 31S housing 31 _E, 31F _E, 31S _E housing 32 holding part 32a groove 32b holding plate 32c spring clip 40 adapter 41 connecting part 42 connecting hole 42C center axis of connecting hole 42a guide part 42b covering layer inserting part 42c aligning part 50 aligning member 50a both ends of aligning member in longitudinal direction 51 Opening 51a Chamfered Diameter Expansion 60 Receptacle 61 Optical Component 62 Positioning Surface ΔL Protrusion Amount W Opening Width H Opening Height

Claims (2)

A plurality of connecting holes are fitted into an aligned connecting member and constitute an optical connector with the connecting member, and the plug includes a housing having a holding portion for holding a plurality of optical fibers in an aligned state. The connecting end portions of the plurality of optical fibers protruding from the holding portion of the housing each have a covering portion that includes a covering layer that covers the strands of the optical fibers and a tip portion from which the covering layer has been removed. These plugs are inserted into the plurality of connection holes of the connection member in accordance with the plug fitting operation with respect to the connection member.
An alignment member is provided on the covering portion of the connection end of the plurality of optical fibers to hold the tip ends of the connection ends of the plurality of optical fibers in an aligned state. The optical connector plug is also arranged close to the distal end side of the connection end of the plurality of optical fibers and is not in contact with the housing.   The optical connector is an optical connector in which the connection end portions of the plurality of optical fibers are buckled in a fitted state of the plug and the connection member, and is along the longitudinal direction of the connection end portions of the plurality of optical fibers. The optical connector plug according to claim 1, wherein the length of the alignment member is 0.5 mm or more and 1.5 mm or less.

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