JP2018169581A - Optical connector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical connector capable of reducing optical loss caused by an optical axis shift between an optical fiber housed in a connector main body and a lens in a lens array. An optical connector (10) includes a connector main body (24) accommodating a plurality of optical fibers arranged in an array, and a lens array (42) including a plurality of lenses (44) corresponding to the plurality of optical fibers. The lens array is composed of at least a base material and a solid material contained in the base material and having a refractive index matched with that of the base material. [Selection diagram] Fig. 1

Description

  The present invention relates to an optical connector having a lens array.

  In constructing an optical wiring using an optical fiber in a data center, it is common to use a multi-fiber optical connector in order to cope with an increase in scale due to an increase in the amount of data communication. In addition, there is an increasing demand for long-distance transmission and large-capacity transmission, and single-mode optical fibers that can satisfy these requirements are used as optical fibers for constructing optical wiring.

  In a multi-fiber optical connector, a physical contact (PC) method and a lens method are known as methods for connecting optical fibers. In the PC method, optical fibers are physically connected by bringing the optical fiber tips in the optical fiber array to be connected to each other by abutment and bringing them into physical contact with each other. On the other hand, in the lens system, a lens array having a lens corresponding to each optical fiber of the optical fiber array is provided in the optical connector, and the optical connector provided with the lens array is fixed so as to face the lens. Optically connect the optical fibers.

  Patent Document 1 describes an optical connector in which a ferrule main body and a lens member on which a plurality of lenses are formed are joined. Patent Document 2 describes an optical fiber assembly including a ferrule body having a plurality of optical fibers positioned therein, and a beam expanding element having a lens array aligned with the optical fibers.

JP-A-2006-9081 Special table 2014-517356 gazette

  In the case of the PC system, the pressing force required to physically contact each optical fiber of the optical fiber array is proportional to the number of cores of the optical fiber array. However, the pressing force cannot be increased without limitation from the viewpoint of the strength of the member and the insertion / removability of the optical connector. For this reason, in the case of the PC system, it is difficult to cope with connection of a super-multi-fiber array having, for example, 30 cores or more. On the other hand, in the case of the lens system, since there is no limitation due to the pressing force unlike the PC system, it is possible to cope with connection of a super multi-fiber array.

  However, in the case of the conventional lens system, the difference in coefficient of linear expansion between the connector main body portion where the lens array is provided and the lens array is large. For this reason, a deviation occurs between the optical axis of the optical fiber and the optical axis of the lens in the lens array due to a temperature change, and the optical loss due to the deviation of the optical axis increases.

  The present invention has been made in view of the above, and provides an optical connector that can reduce optical loss due to an optical axis shift between an optical fiber housed in a connector main body and a lens in a lens array. The purpose is to provide.

  According to one aspect of the present invention, the lens includes: a connector main body that accommodates a plurality of optical fibers arranged in an array; and a lens array that includes a plurality of lenses corresponding to the plurality of optical fibers. An optical connector is provided, wherein the array is composed of at least a base material and a solid material contained in the base material and having a refractive index matched with the base material.

  ADVANTAGE OF THE INVENTION According to this invention, the optical loss resulting from the optical axis offset between the optical fiber accommodated in a connector main-body part and the lens in a lens array can be reduced.

FIG. 1 is a perspective view showing an optical connector according to a first embodiment of the present invention. FIG. 2 is an exploded perspective view showing the optical connector according to the first embodiment of the present invention. FIG. 3 is a plan view for explaining the connection of the optical connector according to the first embodiment of the present invention. FIG. 4 is a perspective view showing a case where the optical connectors according to the first embodiment of the present invention are connected in a state of being accommodated in the connector housing of the MPO connector. FIG. 5 is a perspective view showing an optical connector according to the second embodiment of the present invention. FIG. 6 is a plan view for explaining the optical axis deviation between the optical fiber in the optical connector according to the background art and the lens in the lens array.

[First Embodiment]
An optical connector according to a first embodiment of the present invention will be described with reference to FIGS.

  First, the configuration of the optical connector according to the present embodiment will be described with reference to FIGS. 1 and 2. 1 and 2 are a perspective view and an exploded perspective view, respectively, showing the optical connector according to the present embodiment.

  As shown in FIGS. 1 and 2, the optical connector 10 according to the present embodiment includes a ferrule 12, a lens array plate 14, and a pair of guide pins 16 and 16. The optical connector 10 according to the present embodiment is a multi-fiber optical connector, in which a plurality of optical fibers 18 are fixed, and the plurality of optical fibers 18 are respectively connected to a plurality of optical fibers fixed to the other optical connector of the connection partner. It is for connection.

  The plurality of optical fibers 18 fixed to the optical connector 10 according to the present embodiment is used in a form in which a plurality of optical fiber ribbons 20 are laminated. Here, the optical fiber ribbon 20 is obtained by integrally coating a predetermined number of optical fibers 18 arranged in parallel with a coating 22 made of a resin such as an ultraviolet curable resin. The optical fiber 18 is a silica-based optical fiber having a core and a cladding, and is an optical fiber core having a coating made of a resin such as an ultraviolet curable resin on the outer periphery of the glass optical fiber. The plurality of optical fibers 18 are not limited to the form of the optical fiber ribbon, and a plurality of single optical fibers may be used. The plurality of optical fibers 18 may be incorporated in a cable, a cord, or the like. FIG. 1 shows the optical connector 10 according to the present embodiment having a plurality of optical fibers 18 formed of a laminate of a plurality of optical fiber ribbons 20.

  The ferrule 12 is a connector main body portion that accommodates a plurality of optical fibers 18 arranged in an array, and has a ferrule main body portion 24 and a flange portion 26. The ferrule 12 including the ferrule body portion 24 and the flange portion 26 is made of a resin containing a filler as will be described later. In the ferrule 12, the ferrule body portion 24 is provided on the front side (connection end side) of the optical connector 10, and the flange portion 26 is provided on the rear side of the optical connector 10. The ferrule 12 is a ferrule for a multi-fiber optical connector. Specifically, the ferrule 12 is an MT (Mechanically Transferable) ferrule, for example, conforming to or conforming to standards such as IEC 61754-5 by the International Electrotechnical Commission, JIS C 5981 by the Japanese Industrial Standard. .

  The ferrule body portion 24 has a rectangular parallelepiped shape that is flat in the up-down direction of the optical connector 10 and has a rectangular parallelepiped outer shape having a pair of rectangular side surfaces with the front-rear direction of the optical connector 10 as the longitudinal direction. Further, the flange portion 26 has a rectangular parallelepiped shape having two surfaces facing the vertical (height) direction of the optical connector 10 and both surfaces facing the width direction of the optical connector 10 that are both larger and wider than the ferrule body portion 24. It has the outer shape. In addition, the external shape of the ferrule 12 including the ferrule main body part 24 and the collar part 26 is not limited to these, A various external shape can be employ | adopted.

  An optical fiber introduction port 28 for introducing the plurality of optical fibers 18 into the ferrule 12 is formed in the flange portion 26. The optical fiber inlet 28 is formed in the flange 26 so as to penetrate in the front-rear direction of the optical connector 10.

  The ferrule body 24 is formed with a hollow portion 30 connected to the optical fiber inlet 28 of the flange portion 26. An opening 32 connected to the hollow portion 30 is formed on the upper surface of the ferrule body portion 24. The opening 32 is for introducing an adhesive that fixes the optical fiber 18 to the ferrule 12.

  The ferrule body portion 24 has a front side surface perpendicular to the front-rear direction of the optical connector 10 on the front side of the optical connector 10 as a connection side end surface 34.

  A plurality of optical fiber insertion holes 36 into which the plurality of optical fibers 18 are inserted along the optical axis are formed in the front end portion of the ferrule main body 24. The plurality of optical fiber insertion holes 36 are respectively formed along the front-rear direction of the optical connector 10. One end of each of the plurality of optical fiber insertion holes 36 is open to the connection side end face 34. The other ends of the plurality of optical fiber insertion holes 36 are opened so as to be connected to the hollow portion 30.

  The plurality of optical fiber insertion holes 36 are arranged in an array. For example, a predetermined number of rows of optical fiber insertion holes 36 arranged in parallel along the width direction of the optical connector 10 are formed in a plurality of stages in parallel in the vertical direction of the optical connector 10. FIG. 2 shows an example in which five rows of 12 optical fiber insertion holes 36 are formed. The arrangement of the plurality of optical fiber insertion holes 36, the total number of the plurality of optical fiber insertion holes 36, the number of the optical fiber insertion holes 36 per row, and the number of stages of the rows of the optical fiber insertion holes 36 are plural. It can be set as appropriate according to the number of optical fibers 18 and the like. The hole diameter and pitch of the optical fiber insertion hole 36 can also be set as appropriate according to the outer diameter and pitch of the optical fiber 18. Further, the number of stages of the optical fiber insertion hole 36 does not have to be plural, and may be one.

  In addition, as for the some optical fiber 18, the outer diameter of a glass optical fiber part is 80-126 micrometers, for example. In the optical connector 10, when the outer diameter of the glass optical fiber portion is 80 μm, for example, the pitch is 125 μm or 250 μm, and when the outer diameter of the glass optical fiber portion is 125 μm, for example, the pitch is 250 μm. In addition, a pitch is not limited to this, What is necessary is just to set more than the outer diameter of a glass optical fiber.

  In the ferrule 12 configured as described above, the tip portions of the plurality of optical fiber ribbons 20 are introduced into the hollow portion 30 of the ferrule body portion 24 from the optical fiber introduction port 28 of the flange portion 26. The plurality of optical fiber ribbons 20 are stacked in the vertical direction of the optical connector 10. The plurality of optical fiber ribbons 20 may be protected by being covered with a boot or the like at the rear end of the optical connector 10. The coatings 22 are removed from the tip portions of the plurality of optical fiber ribbons 20 introduced into the hollow portion 30, and the glass optical fiber portion of the optical fiber 18 is exposed.

  The optical fiber 18 is inserted and fixed in each of the plurality of optical fiber insertion holes 36 formed in the ferrule body 24. The plurality of optical fibers 18 inserted and fixed in the plurality of optical fiber insertion holes 36 in the same row are included in the same optical fiber ribbon 20. The optical fiber 18 is bonded and fixed to the optical fiber insertion hole 36 by an adhesive introduced from the opening 32 on the upper surface of the ferrule main body 24. End portions of the plurality of optical fiber ribbons 20 introduced into the hollow portion 30 are also bonded and fixed to the ferrule body portion 24 with an adhesive introduced from the opening 32. The adhesive for adhering these is not particularly limited, and for example, an epoxy resin adhesive can be used. The optical fiber 18 inserted and fixed in the optical fiber insertion hole 36 may be covered with a resin coating, or may be in a state where the resin coating is removed.

  The end face of the optical fiber 18 fixed in the optical fiber insertion hole 36 is polished together with the connection side end face 34 of the ferrule body 24 to be aligned with the connection side end face 34. Thus, the ferrule 12 accommodates the plurality of optical fibers 18 so that the plurality of optical fibers 18 are arranged in an array. In the ferrule 12 that accommodates the plurality of optical fibers 18, a fiber array including the plurality of optical fibers 18 is configured.

  Further, in the width direction of the optical connector 10, a pair of guide pin insertion holes 38 into which the guide pins 16 are respectively inserted at both side end portions on both sides of the plurality of optical fiber insertion holes 36 and the hollow portion 30 of the ferrule body portion 24. , 38 are formed. The pair of guide pin insertion holes 38, 38 are formed along the front-rear direction of the optical connector 10, respectively.

  The lens array plate 14 is attached to the connection-side end surface 34 of the ferrule body 24. The lens array plate 14 is a lens array including a plurality of lenses 44 corresponding to the plurality of optical fibers 18 accommodated in the ferrule 12.

  The lens array plate 14 is made of a resin containing a filler as will be described later. The lens array plate 14 has a rectangular parallelepiped shape flattened in the front-rear direction of the optical connector 10 and has a rectangular parallelepiped outer shape having a side surface that contacts the connection-side end surface 34 of the ferrule main body 24. In the present embodiment, the case where the lens array plate 14 is configured as a component separate from the ferrule 12 will be described. However, the lens array plate 14 may be formed integrally with the ferrule 12. The case where the lens array plate 14 is formed integrally with the ferrule 12 and both are configured as a single component will be described in a second embodiment to be described later.

  The lens array plate 14 has a front side surface perpendicular to the front-rear direction of the optical connector 10 on the front side of the optical connector 10 as a connection-side end surface 40. The connection side end surface 40 is a surface that faces and contacts another optical connector of the other party of the connection. More specifically, the connection-side end surface 40 is a surface that faces and contacts the connection-side end surface of the lens array plate of the other optical connector to be connected. A lens array portion 42 is formed on the connection side end face 40. In addition, the other optical connector of the other party of a connection also has the structure similar to the optical connector 10 by this embodiment.

  The lens array portion 42 is a concave portion that is recessed in the front-rear direction of the optical connector 10 from the connection-side end surface 40. On the bottom surface of the lens array portion 42, a plurality of lenses 44 are arranged in an array corresponding to the plurality of optical fibers 18 arranged on the connection side end surface 34 of the ferrule main body portion 24.

  Each of the plurality of lenses 44 has a convex curved surface on the connection side end face 40 side, and is formed so that the direction along the front-rear direction of the optical connector 10 is the optical axis. Each lens 44 may be a spherical lens or an aspherical lens. The plurality of lenses 44 are formed on the bottom surface of the lens array portion 42 at a height lower than the depth of the concave portion of the lens array portion 42. For this reason, the plurality of lenses 44 are located closer to the ferrule 12 than the connection side end face 40 of the lens array plate 14. The plurality of lenses 44 are formed so that the optical axes corresponding to the corresponding optical fibers 18 are aligned.

  The plurality of lenses 44 can function as a collimating lens that collimates the light emitted from the corresponding optical fiber 18 toward the lens 44 into parallel light and emits the light toward the other optical connector to be connected. The plurality of lenses 44 are condensing lenses that condense parallel light incident from the optical connector of the other end of the connection toward the lens 44 onto the end face of the corresponding optical fiber 18 and enter the optical fiber 18. Can also work.

  In the width direction of the optical connector 10, a pair of guide pin insertion holes 46, 46 into which the guide pins 16 are respectively inserted are formed at both end portions on both sides of the lens array portion 42 of the lens array plate 14. The pair of guide pin insertion holes 46 is formed along the front-rear direction of the optical connector 10. The pair of guide pin insertion holes 46, 46 are formed corresponding to the pair of guide pin insertion holes 38, 38 of the ferrule body 24.

  The lens array plate 14 configured as described above is formed by the pair of guide pins 16 inserted into the pair of guide pin insertion holes 46 and 46 and the pair of guide pin insertion holes 38 and 38 of the ferrule body 24. It is attached. The lens array plate 14 is positioned with respect to the ferrule body 24, that is, with respect to the ferrule 12 by a pair of guide pins 16 and 16. The lens array plate 14 may be further bonded and fixed to the connection side end surface 34 of the ferrule main body 24 with an adhesive or the like. The guide pins 16 inserted into the guide pin insertion holes 46 and 38 have portions protruding forward from the lens array plate 14 in order to be inserted into and connected to the optical connector of the other party of connection.

  Thus, the optical connector 10 according to the present embodiment having the plurality of optical fibers 18 accommodated and fixed in the ferrule 12 is configured.

  Hereinafter, materials constituting the lens array plate 14 and the ferrule 12 in the optical connector according to the present embodiment will be described in detail.

  The lens array plate 14 including the plurality of lenses 44 includes at least a base material and a filler that is a solid material that is contained in the base material and has a refractive index that matches the base material. More specifically, as described below, the lens array plate 14 includes a base material including at least one of a thermoplastic resin and a thermosetting resin, and a filler that is a solid material made of a material different from the base material. It is composed of a mixed material. The lens array plate 14 is formed by molding a mixed material of a base material and a filler. The molding method of the lens array plate 14 is not particularly limited, and for example, a transfer molding method, an injection molding method, or the like can be used.

  The base material used for the lens array plate 14 includes at least one of a thermoplastic resin and a thermosetting resin, and is transparent to signal light that can propagate through the plurality of optical fibers 18. A thermoplastic resin is a resin that is softened by heating and hardened by cooling. The thermosetting resin is a resin that is cured by heating. Examples of the thermoplastic resin used for the base material of the lens array plate 14 include polycarbonate (PC), polyethersulfone (PES), cycloolefin polymer (COP), and cyclic olefin copolymer (cyclo). Amorphous resins such as olefin copolymer (COC) and polyetherimide (PEI) may be used. Moreover, as a thermosetting resin used for the base material of the lens array plate 14, for example, urea resin (urea formaldehyde resin, UF), melamine resin (melamine formaldehyde resin, MF), or the like may be used.

  The filler used for the lens array plate 14 is a solid material having a refractive index matched with the base material constituting the lens array plate 14 and has transparency to signal light that can propagate through the plurality of optical fibers 18. It is. As the filler of the lens array plate 14, for example, a solid material obtained by processing quartz glass or quartz crystal into a predetermined shape may be used. The filler of the lens array plate 14 is blended with the base material in order to reduce the linear expansion coefficient of the lens array plate 14.

  The filler of the lens array plate 14 is preferably blended so as to have a volume of 40% or more with respect to the volume of the lens array plate 14, that is, the volume of the mixed material of the base material and the filler. When the weight% is used, the filler of the lens array plate 14 may be blended so as to be 60% or more of the weight of the lens array plate 14, that is, the weight of the mixture of the base material and the filler. preferable. Thus, the linear expansion coefficient of the lens array plate 14 including the plurality of lenses 44 can be reduced to 50 ppm / ° C. or less by blending the filler with high filling. From the viewpoint of ensuring good transparency, the filler of the lens array plate 14 is preferably blended so as to have a volume of 55% or less with respect to the volume of the lens array plate 14. When using% by weight, the filler of the lens array plate 14 is preferably blended so as to have a weight of 75% or less with respect to the weight of the lens array plate 14. The linear expansion coefficient of the lens array plate 14 including the plurality of lenses 44 is preferably 30 ppm / ° C. or higher, corresponding to such a preferable lower limit value of the filler content. Thus, the linear expansion coefficient of the lens array plate 14 is preferably 50 ppm / ° C. or less, and more preferably 30 ppm / ° C. or more and 50 ppm / ° C. or less.

  Since the linear expansion coefficient of the lens array plate 14 is reduced as described above, the difference between the linear expansion coefficient of the lens array plate 14 and the linear expansion coefficient of the ferrule 12 is, for example, 10 ppm / ° C. or less. Yes. As will be described later, when the ferrule 12 is made of the same material as the lens array plate 14, the linear expansion coefficient of the ferrule 12 and the linear expansion coefficient of the lens array plate 14 coincide.

  In the lens array plate 14, the filler is configured so that the refractive index of the base material matches. That is, in the lens array plate 14, the filler has no difference between the refractive index of the filler and the refractive index of the base material, or the difference between the refractive index of the filler and the refractive index of the base material is a predetermined value. It is configured to be less than or equal to the value. The refractive index may be adjusted by a known method, for example, by adding inorganic particles to the base material or filler. The difference between the refractive index of the filler and the refractive index of the base material in the lens array plate 14 is preferably 0.03 or less. When there is a difference between the refractive indexes, the relationship between the refractive indexes of the two may be a relationship in which the refractive index of the filler is larger than the refractive index of the base material, or the refractive index of the filler is the refractive index of the base material. The relationship may be smaller than the rate.

  In addition, it is preferable that the refractive index matching with respect to the base material of the filler in the lens array plate 14 is established in the wavelength range used as the wavelength of the signal light that can propagate through the plurality of optical fibers 18. Specifically, it is preferable that the filler is configured so that the refractive index matches the base material for light in the wavelength range of 800 nm to 1700 nm. That is, it is preferable that the difference between the refractive index of the filler and the refractive index of the base material in the lens array plate 14 is 0 or 0.03 or less for light in the wavelength range of 800 nm to 1700 nm. The wavelength range of 800 nm to 1700 nm includes the 0.85 μm band, 1.3 μm band, 1.55 μm band, 1.625 μm, and 1.65 μm wavelength bands used as the wavelength of signal light in optical communication. .

  Thus, in the lens array plate 14, the filler is configured so that the refractive index matches the base material, so that the lens array plate 14 including the plurality of lenses 44 can propagate the signal light that can propagate through the plurality of optical fibers 18. Is transparent. Thereby, in the some lens 44, the light loss by scattering resulting from the refractive index difference between a filler and a base material can be suppressed small enough.

  As the filler of the lens array plate 14, a spherical filler made of a spherical solid material or a fiber crushed filler obtained by crushing a fibrous solid material may be used. The spherical filler preferably has an average particle size of 10 μm or more and 50 μm or less. The fiber crushing filler preferably has a fiber diameter of 50 μm or less and an average fiber length of 100 μm or less. When the fiber crushing filler is used, the anchor effect of connecting the base material is increased by the shape of the crushed fiber, so that the effect of improving the strength of the lens array plate 14 can be obtained. Further, in the step of pelletizing the mixture of the base material and the filler, an effect of stabilizing the extrusion and improving the manufacturability can be obtained by a high anchor effect.

  In addition, the lens array plate 14 should just be comprised from the base material and filler which were mentioned above at least, and may further be comprised including materials other than the base material mentioned above and a filler.

  On the other hand, the ferrule 12 including the ferrule body portion 24 and the flange portion 26 is a mixture of a base material containing a resin and a filler that is a solid material made of a material different from the base material, which is used for a general resin ferrule. It is configured. The ferrule 12 is formed by molding a mixed material. In addition, although the molding method of the ferrule 12 is not specifically limited, For example, a transfer molding method, an injection molding method, etc. can be used.

  The base material used for the ferrule 12 includes at least one of a thermoplastic resin and a thermosetting resin. Examples of the thermoplastic resin used for the base material of the ferrule 12 include polyphenylene sulfide (PPS), liquid crystal polymer (LCP), polyethersulfone (PES), polycarbonate (PC), and cycloolefin. A polymer (COP) or the like may be used. Moreover, as a thermosetting resin used for the base material of the ferrule 12, for example, an epoxy resin, a phenol resin, a urea resin, a melamine resin, an unsaturated polyester resin, or the like may be used.

  As the filler used for the ferrule 12, for example, a solid material obtained by processing quartz glass or quartz crystal into a predetermined shape may be used. The filler of the ferrule 12 is blended in the base material in order to reduce the linear expansion coefficient of the ferrule 12.

  The blending ratio of the ferrule 12 is not particularly limited, but it is blended so that the volume of the ferrule 12 is 55% or more with respect to the volume of the ferrule 12, that is, the volume of the mixed material of the base material and the filler. It is preferable. When using% by weight, the filler of the ferrule 12 is preferably blended so as to have a weight of 65% or more with respect to the weight of the ferrule 12, that is, the weight of the mixed material of the base material and the filler. By blending the ferrule 12 with such a blending ratio, it is possible to secure the molding accuracy of the ferrule 12 by reducing the linear expansion coefficient while securing the strength of the ferrule 12.

  Thus, the linear expansion coefficient of the ferrule 12 in which the filler is blended is not particularly limited, but is preferably 40 ppm / ° C. or less, more preferably 20 ppm / ° C. or less.

  As the filler of the ferrule 12, similarly to the filler of the lens array plate 14, a spherical filler made of a spherical solid material or a fiber crushed filler obtained by crushing a fibrous solid material may be used. As the filler of the ferrule 12, the average particle diameter when a spherical filler is used, and the fiber diameter and average fiber length when a fiber crushing filler is used are preferably set similarly to the filler of the lens array plate 14. .

  The ferrule 12 may be made of the same material as the lens array plate 14. That is, the same material as the base material of the lens array plate 14 can be used as the base material of the ferrule 12, and the same filler as the filler of the lens array plate 14 can be used as the filler of the ferrule 12. By making the ferrule 12 of the same material as the lens array plate 14 in this way, the linear expansion coefficient of the ferrule 12 and the linear expansion coefficient of the lens array plate 14 can be matched.

  In addition, the ferrule 12 should just be comprised from the base material and filler which were mentioned above at least, and may further be comprised including materials other than the base material and filler mentioned above.

  As described above, in the optical connector 10 according to the present embodiment, the lens array plate 14 including the plurality of lenses 44 is composed of the mixed material including the filler whose refractive index is matched with the base material. By including the filler, the linear expansion coefficient of the lens array plate 14 is suppressed to be small, so that expansion and contraction of the lens array plate 14 due to a temperature change can be suppressed. As a result, in the optical connector 10 according to the present embodiment, the optical axis deviation between the plurality of optical fibers 18 accommodated and fixed in the ferrule 12 and the plurality of lenses 44 in the lens array plate 14 is suppressed, and the optical axis deviation is suppressed. It is possible to reduce the optical loss due to.

  In general, the main body portion of an optical connector such as an MT ferrule needs to have a low linear expansion coefficient in order to ensure molding accuracy, and therefore contains a large amount of filler having a low linear expansion coefficient. On the other hand, since it is necessary to ensure transparency, the lens array plate is fillerless unlike the main body of the optical connector. Since there is a difference in coefficient of linear expansion between the main body of the optical connector including the filler and the lens array without the filler, the difference in dimensional change between the two due to temperature change is large. The difference in dimensional change due to temperature change contributes to the optical axis misalignment between the optical fiber and the corresponding lens.

  The optical axis shift in the optical connector according to the background art in which the lens array plate is fillerless will be described with reference to FIG. FIG. 6 is a plan view for explaining an optical axis shift in the optical connector according to the background art. FIG. 6A is a plan view showing an optical connector according to the background art. FIG. 6B is a plan view showing the expansion of the optical connector when the optical connector according to the background art is placed in a high temperature environment. FIG. 6C is a plan view showing the contraction of the optical connector when the optical connector according to the background art is placed in a low temperature environment.

  As shown in FIG. 6A, an optical connector 310 according to the background art includes a ferrule 312 in which a plurality of optical fibers 318 are accommodated and fixed, and a lens array including a plurality of lenses 344 corresponding to the plurality of optical fibers 318. Plate 314. Optical fiber 318 represents a glass optical fiber portion having a core 318a and a cladding 318b with the coating removed. A plurality of optical fibers 318 are accommodated in the ferrule 312. The lens array plate 314 is attached to the front side surface of the ferrule 312. The ferrule 312 is made of a resin containing a filler. On the other hand, unlike the ferrule 312, the lens array plate 314 including a plurality of lenses 344 is made of a resin that does not include a filler.

  When the optical connector 310 according to the background art is placed in a high temperature environment, both the ferrule 312 and the lens array plate 314 will expand. However, the fillerless lens array plate 314 has a higher coefficient of linear expansion than the ferrule 312 containing the filler. Therefore, as shown in FIG. 6B, the lens array plate 314 is larger than the ferrule 312 and expands outward in the width direction of the optical connector 310. In FIG. 6B, the direction of expansion due to the high temperature environment is indicated by an arrow, and the magnitude of expansion is indicated by the size of the arrow. As a result, a large dimensional change difference occurs between the ferrule 312 and the lens array plate 314. For this reason, an optical axis deviation De is generated between the optical fiber 318 fixed to the ferrule 312 and the corresponding lens 344 due to a difference in dimensional change.

  When the optical connector 310 according to the background art is placed in a low temperature environment, both the ferrule 312 and the lens array plate 314 contract. However, due to the difference in linear expansion coefficient between the two due to the presence or absence of the filler, the lens array plate 314 contracts more in the width direction of the optical connector 310 than the ferrule 312 as shown in FIG. In FIG. 6C, the direction of shrinkage caused by the low temperature environment is indicated by an arrow, and the magnitude of shrinkage is indicated by the size of the arrow. As a result, a large dimensional change difference occurs between the ferrule 312 and the lens array plate 314. For this reason, an optical axis deviation Dc occurs between the optical fiber 318 fixed to the ferrule 312 and the corresponding lens 344 due to a difference in dimensional change.

  As described above, in the optical connector 310 according to the background art, an optical axis shift that causes light loss occurs between the optical fiber 318 housed and fixed in the ferrule 312 and the lens 344 in the lens array plate 314. .

  On the other hand, in the optical connector 10 according to the present embodiment, the lens array plate 14 includes a filler, and thus has a lower linear expansion coefficient than the filler-less lens array plate 314 according to the background art. . As a result, in the optical connector 10 according to the present embodiment, the linear expansion coefficient of the lens array plate 14 is closer to the linear expansion coefficient of the ferrule 12 than in the case of fillerless according to the background art. Thereby, the optical connector 10 according to the present embodiment can suppress a difference in dimensional change between the ferrule 12 and the lens array plate 14 due to a temperature change. Thus, the optical connector 10 according to the present embodiment can reduce optical loss due to the optical axis shift between the optical fiber 18 housed and fixed in the ferrule 12 and the lens 44 in the lens array plate 14.

  Furthermore, in the optical connector 10 according to the present embodiment, the ferrule 12 can be made of the same material as the lens array plate 14 as described above. In this case, the linear expansion coefficient of the ferrule 12 and the linear expansion coefficient of the lens array plate 14 can be matched. By matching the linear expansion coefficients of the two, the difference in dimensional change between the ferrule 12 and the lens array plate 14 due to a temperature change can be further reduced, and thus the optical loss due to the optical axis shift described above. Can be further reduced.

  Moreover, in the optical connector 10 according to the present embodiment, in the lens array plate 14, the filler is configured so that the refractive index matches the base material. For this reason, in the optical connector 10 according to the present embodiment, the plurality of lenses 44 can maintain transparency with respect to the signal light that can propagate through the plurality of optical fibers 18. Therefore, in the optical connector 10 according to the present embodiment, the optical loss due to the refractive index between the filler and the base material in the lens array plate 14 can be suppressed sufficiently small.

  As described above, according to the present embodiment, it is possible to reduce the optical loss due to the optical axis shift between the optical fiber 18 and the lens 44 in the lens array plate 14.

  The optical connector 10 according to the present embodiment can be connected to the optical connector 10 having a similar structure. Hereinafter, the connection of the optical connector 10 according to the present embodiment will be described with reference to FIG. FIG. 3 is a plan view for explaining the connection of the optical connector 10 according to the present embodiment. 3A shows a state before connection, FIG. 3B shows a state during connection, and FIG. 3C shows a state after connection is completed. In FIG. 3, of the two optical connectors 10 connected to each other, the male optical connector 10 is indicated by a symbol “10M”, and the female optical connector 10 is indicated by a symbol “10F”. To do. In the male optical connector 10M, a pair of guide pins 16 and 16 are inserted and attached to the guide pin insertion holes 38 and 46, respectively. In the female optical connector 10F, the guide pin 16 is not inserted into the guide pin insertion holes 38 and 46. Further, in FIG. 3, for the sake of convenience, each part is shown in a dimensional ratio different from that in FIGS. FIG. 3 shows a glass optical fiber portion having a core 18a and a clad 18b from which the coating has been removed.

  First, as shown in FIG. 3A, the male optical connector 10M and the female optical connector 10F to be connected to each other are opposed to each other with the connection side end face 40 of the lens array plate 14 facing each other. At this time, the positions of the pair of guide pins 16 and 16 attached to the male optical connector 10M are matched with the positions of the pair of guide pin insertion holes 46 and 46 in the lens array plate 14 of the female optical connector 10F. The lens 44 in the male optical connector 10M faces the corresponding lens 44 in the female optical connector 10F.

  Next, as shown in FIG. 3B, the protruding portions of the pair of guide pins 16 of the male optical connector 10M are inserted into the guide pin insertion holes 38 and 46 of the female optical connector 10F, respectively.

  Next, as shown in FIG. 3C, all of the protruding portions of the pair of guide pins 16 of the male optical connector 10M are inserted into the guide pin insertion holes 38 and 46 of the female optical connector 10F, respectively. Thus, the optical connector 10M and the optical connector 10F are brought into contact with each other, and the connection side end faces 40 of the lens array plates 14 are brought into contact with each other.

  In the lens array plate 14, the plurality of lenses 44 are formed on the bottom surface of the lens array portion 42 that is formed in a recessed portion that is recessed from the connection-side end surface 40 as described above. Therefore, the plurality of lenses 44 are located closer to the ferrule 12 than the connection side end surface 40 of the lens array plate 14, and are retracted from the connection side end surface 40 by the recess R. Therefore, in the optical connectors 10M and 10F connected to each other, the contact of the facing lens 44 can be prevented. Further, the distance between the facing lenses 44 and 44 is twice the recess R. For this reason, by appropriately setting the size of the recess R, the distance between the opposing lenses 44 and 44 can be maintained at an appropriate distance.

  Thus, the optical connector 10M and the optical connector 10F are connected by the pair of guide pins 16 and 16. The plurality of optical fibers 18 of the optical connector 10M are optically connected to the corresponding optical fibers 18 of the optical connector 10F via two lenses 44, 44 facing each other.

  The optical connector 10M and the optical connector 10F described above may be accommodated in a connector housing such as an MPO (Multifiber Push-On) connector. Hereinafter, the case where the optical connector 10M and the optical connector 10F are connected in a state of being accommodated in the connector housing of the MPO connector will be further described with reference to FIG. FIG. 4 is a perspective view showing a case where the optical connector 10M and the optical connector 10F are connected in a state of being accommodated in the connector housing of the MPO connector. The MPO connector using the optical connector 10M and the optical connector 10F conforms to or conforms to standards such as IEC 61754-7 by the International Electrotechnical Commission, JIS C 5964-7 by the Japanese Industrial Standards, JIS C 5982, etc. It has become.

  As shown in FIG. 4, the ends of the male optical connector 10M and the optical fiber ribbon 20 connected thereto are accommodated in a connector housing 50 of the MPO connector. The connector housing 50 includes a housing main body 52, a cylindrical portion 54 provided on the outer periphery of the housing main body 52 so as to be slidable with respect to the housing main body 52, and a boot portion connected to the rear end of the housing main body 52. 56.

  The housing main body 52 accommodates and holds the optical connector 10M. Part of the lens array plate 14 and the ferrule main body 24 of the optical connector 10M protrudes from the front end that is the connection side of the housing main body 52. A biasing mechanism (not shown) including an elastic body such as a coil spring is provided in the housing main body 52 and the boot portion 56, and the optical connector 10M is biased forward by this biasing mechanism.

  In the boot portion 56, a plurality of optical fiber ribbons 20 including a plurality of optical fibers 18 fixed to the optical connector 10M are accommodated. The plurality of optical fiber ribbons 20 may be incorporated in a cable, a cord, or the like.

  Similarly to the male optical connector 10M, the female optical connector 10F is accommodated in the connector housing 50 of the MPO connector.

  The optical connectors 10M and 10F housed in the connector housing 50 are connected via an adapter 58.

  The adapter 58 is formed with a housing insertion hole 60 extending therethrough. The housing insertion hole 60 can insert the front end portion of the housing main body 52 from both ends.

  A recess 64 corresponding to a key 62 that is a protrusion formed on the housing main body 52 that accommodates the male optical connector 10M is formed at one end of the housing insertion hole 60. At the other end portion of the housing insertion hole 60, a recess 64 corresponding to the key 62, which is a projection formed on the housing main body 52 that accommodates the female optical connector 10F, is formed. Thereby, the front end portion of the housing main body portion 52 that accommodates the male optical connector 10M is inserted into the housing insertion hole 60 from one end side thereof, and the housing main body portion that accommodates the female optical connector 10F from the other end side. 52 is inserted. In FIG. 4, the key 62 is shown only for the housing main body 52 that accommodates the male optical connector 10 </ b> M, and the recess 64 is shown only for the other end portion of the housing insertion hole 60.

  In addition, a hook portion 66 is formed at one end of the housing insertion hole 60 so as to be detachably hooked to the housing main body 52 that accommodates the male optical connector 10M and to fix the housing main body 52. A hook portion 66 is formed at the other end portion of the housing insertion hole 60 so as to be detachably hooked to the housing main body 52 that accommodates the female optical connector 10F and to fix the housing main body 52. With these hook portions 66, the housing main body portion 52 for accommodating the male optical connector 10M inserted into the housing insertion hole 60 from one end side and the housing main body portion 52 for accommodating the female optical connector 10F can be attached and detached. 58 is fixed. In FIG. 4, the hook portion 66 is shown only for the other end portion of the housing insertion hole 60.

  When connecting the optical connectors 10M and 10F, the housing main body portions 52 and 52 that accommodate the optical connectors 10M and 10F are inserted into the housing insertion hole 60 from one end side and the other end side of the housing insertion hole 60, respectively. Then, each housing main-body part 52 is fixed to the adapter 58 so that attachment or detachment is possible as mentioned above. At the same time, in the housing insertion hole 60, the pair of guide pins 16 and 16 of the male optical connector 10M are inserted and fixed in the guide pin insertion holes 38 and 46 of the female optical connector 10F, respectively. Further, in the housing insertion hole 60, the optical connector 10M and the optical connector 10F are abutted with each other, and the connection side end faces 40 of the lens array plates 14 are in contact with each other (see FIG. 3). The optical connectors 10M and 10F are urged forward by the urging mechanism as described above. For this reason, the connection side end surfaces 40 of the lens array plate 14 of the optical connectors 10M and 10F are in close contact with each other.

  Thus, the optical connector 10M and the optical connector 10F housed in the connector housing 50 are connected via the adapter 58.

(Example)
In Examples 1 to 4 according to the first embodiment, a base material made of polycarbonate which is a thermoplastic resin and a spherical filler made of quartz glass are pelletized, and a lens array plate is manufactured using the pellet. A transfer molding method was used for molding the lens array plate. The refractive index of the base material made of polycarbonate was 1.585. As the spherical filler of quartz glass, one having a refractive index of 1.570 and an average particle diameter of 20 μm was used. The difference between the refractive index of the base material and the refractive index of the filler was 0.015. The average molecular weight of the base material and the blending ratio of the filler were set as shown in Table 1 below. And about the produced lens array plate, while measuring a linear expansion coefficient, the moldability and the suppression effect of an optical axis shift were evaluated. In Table 1, an evaluation result is shown with the average molecular weight of a base material, and the compounding rate of a filler.

  As shown in Table 1, in any of Examples 1 to 4, when the lens array plate was molded, the fluidity of the material was good, and the moldability of the molded body was good.

  In any of Examples 1 to 4, the linear expansion coefficient was suppressed to 50 ppm / ° C. or lower by increasing the filler content. As a result, in any of the first to fourth embodiments, it is possible to sufficiently suppress the optical axis shift between the optical fiber arranged and fixed on the MT ferrule and the lens in the lens array plate. A good suppression effect was obtained.

[Second Embodiment]
An optical connector according to a second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a perspective view showing the optical connector according to the present embodiment. The same components as those of the optical connector according to the first embodiment are denoted by the same reference numerals, and the description thereof is omitted or simplified.

  The basic configuration of the optical connector according to the present embodiment is substantially the same as the configuration of the optical connector 10 according to the first embodiment. The optical connector according to the present embodiment is different from the optical connector 10 according to the first embodiment in that the ferrule 12 and the lens array plate 14 are integrally formed.

  As shown in FIG. 5, in the optical connector 210 according to the present embodiment, the ferrule 12 and the lens array plate 14 are formed integrally with each other. For this reason, in this embodiment, the ferrule 12 and the lens array plate 14 are comprised as a single component.

  The ferrule 12 and the lens array plate 14 that are integrally formed with each other are made of the same mixture as the lens array plate 14 according to the first embodiment. That is, the ferrule 12 and the lens array plate 14 according to the present embodiment are composed of a mixed material of a base material and a filler, and the filler is configured so that the refractive index of the base material matches that of the first embodiment. Has been. The molding method of the ferrule 12 and the lens array plate 14 that are integrally formed is not particularly limited. For example, a transfer molding method, an injection molding method, or the like can be used.

  In the optical connector 210 according to the present embodiment, since the ferrule 12 and the lens array plate 14 are integrally formed with each other, the linear expansion coefficient of the ferrule 12 and the linear expansion coefficient of the lens array plate 14 can be made to substantially coincide. it can. Thereby, the optical connector 210 according to the present embodiment can further suppress a difference in dimensional change between the ferrule 12 and the lens array plate 14 due to a temperature change. Thus, the optical connector 210 according to the present embodiment can further reduce the optical loss due to the optical axis shift between the optical fiber 18 and the lens 44 of the lens array plate 14.

[Modified Embodiment]
The present invention is not limited to the above embodiment, and various modifications can be made.

  For example, although the case where the ferrule 12 is an MT ferrule has been described as an example in the above embodiment, the present invention is not limited to this. As the ferrule 12, various types of ferrules can be adopted as long as they are ferrules for multi-fiber connectors.

  In the above embodiment, the case where the lens array plate 14 is attached to the ferrule 12 using the guide pins 16 has been described as an example, but the present invention is not limited to this. As a method of attaching the lens array plate 14 to the ferrule 12, various methods such as a method using only an adhesive without using the guide pins 16 can be used.

DESCRIPTION OF SYMBOLS 10, 10M, 10F, 210 ... Optical connector 12 ... Ferrule 14 ... Lens array plate 16 ... Guide pin 18 ... Optical fiber 20 ... Optical fiber tape core wire 24 ... Ferrule main-body part 42 ... Lens array part 44 ... Lens 50 ... Connector housing 58 ... Adapter

Claims (11)

A connector main body for accommodating a plurality of optical fibers arranged in an array; and
A lens array including a plurality of lenses corresponding to the plurality of optical fibers,
The lens array is at least
A base material;
An optical connector comprising a solid material contained in the base material and having a refractive index matched with the base material. The connector body is an MT ferrule;
The optical connector according to claim 1, wherein the lens array is positioned by a guide pin with respect to the connector main body.   The optical connector according to claim 1, wherein the connector main body is made of the same material as the lens array. The connector body and the lens array are integrally formed,
4. The optical connector according to claim 1, wherein the connector main body and the lens array that are integrally formed are formed of at least the base material and the solid material. 5. . The base material includes at least one of a thermoplastic resin and a thermosetting resin,
The solid material is made of a material different from the base material,
5. The difference between the refractive index of the solid material and the refractive index of the base material is 0.03 or less for light in a wavelength range of 800 nm to 1700 nm. The optical connector according to claim 1.   The optical connector according to claim 1, wherein the lens array has a linear expansion coefficient of 50 ppm / ° C. or less.   The optical connector according to claim 6, wherein a difference between a linear expansion coefficient of the lens array and a linear expansion coefficient of the connector main body is 10 ppm / ° C. or less.   The optical connector according to claim 1, wherein the solid material is made of quartz glass.   9. The optical connector according to claim 1, wherein the solid material has a spherical shape and an average particle diameter of 10 μm to 50 μm.   The optical connector according to any one of claims 1 to 8, wherein the solid material is obtained by crushing fibers, having a fiber diameter of 50 µm or less and an average fiber length of 100 µm or less. .   The optical connector according to claim 1, comprising the plurality of optical fibers housed in the connector main body.

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