JP2006208731A - Multiple-type optical receptacle and optical module using the same - Google Patents

Abstract

In a method of fixing an optical receptacle that is optically connected to a multi-core optical connector, in the case of an optical module that uses a fiber stub, a fiber of each optical module is connected to each ferrule of the multi-core optical connector to be connected. Each stub needs to be positioned, and there is a problem that a connection loss occurs because an inclination / deviation within the receptacle clearance with respect to the housing always occurs.
An optical receptacle comprising a fiber stub that holds an optical fiber in an inner hole of a ferrule, and a sleeve that holds a tip portion of the fiber stub, wherein a plurality of the optical receptacles are arranged, and a plurality of The holder has a through hole, and a holder for fixing the rear end of the fiber stub at each through hole.
[Selection] Figure 1

Description

  The present invention relates to a receptacle used for an optical communication module or the like.

  An optical module for converting an optical signal into an electrical signal has a structure in which an optical element such as a semiconductor laser or a photodiode is housed in a case, and the optical signal is introduced into or derived from an optical fiber via a lens or the like. It has become. FIG. 4 shows an optical module to which a connector is connected among such optical modules. The receptacle type optical module shown in FIG. 4 includes an optical element 21 in the optical receptacle 8 and a plug ferrule 6 connected to the other.

  The optical receptacle 8 shown in FIG. 4 is fixed by press-fitting the rear end portion of the fiber stub 1 in which the fiber 2 is bonded and fixed to the inner diameter of a holder 3 formed by cutting or injection molding a stainless steel base material. The tip 5 of the stub 1 is gripped by a sleeve 4 having a slit made of ceramic or the like, and a cover 5 made of a stainless steel base material is cut or injection molded at the inner diameter of the holder 3 to prevent the sleeve 4 from coming off. It is configured by bonding or press-fitting.

  In recent years, with the spread of the Internet and the like, optical transmission has become common in data communications, and optical communication transceivers, which are the key devices, are required to simultaneously realize high speed, small size, and low cost. ing. In addition, along with the downsizing of this optical communication transceiver, an optical receptacle type in which a two-core optical connector plug ferrule paired for transmission and reception is also commonly used is shown in FIG. As shown in FIG. 5, a transmission optical module and a reception optical module are arranged in parallel and used (see, for example, Patent Document 1).

At this time, as a positioning method for arranging the optical modules in parallel with respect to the two-core optical connector plug ferrule, the transmitting optical receptacle 8a and the receiving optical receptacle 8b are respectively fixed to the grooves 31a of the housing 31. It was carried out.
JP 2002-82261 A

  However, in the conventional optical receptacle fixing method as shown in FIG. 5, which is optically connected to a multi-core optical connector plug ferrule, in the case of an optical module using a fiber stub 1 as shown in FIG. It is necessary to position the fiber stub 1 of the optical module corresponding to the optical connector plug ferrule 6, the positional deviation between the holder 3 and the fiber stub 1, the groove 31 a of the housing 31 and the optical receptacle 8 a of FIG. 5, Inclination / displacement within the clearance of 8b is inevitably generated and loss occurs, so that there is a problem that each part must be processed and attached with high precision in order to accurately match each plug ferrule 6. .

  For optical modules that require high coupling, when assembling the optical receptacle and optical element, the slanted polished surface of the receptacle and the tilt direction of the optical axis of the optical element must be aligned to the optimum position in order to achieve high optical coupling. The optical element is fixed while being shifted in the vertical direction with respect to the central axis of the fiber stub of the optical receptacle. For this reason, when a plurality of optical modules are provided, it is necessary to align the optical elements of each optical module in one direction, and there is a problem that the fixing of the optical receptacle in the optical module becomes complicated.

In view of the above, the multiple optical receptacle of the present invention is an optical receptacle comprising a fiber stub that holds an optical fiber in the inner hole of a ferrule, and a sleeve that holds the tip of the fiber stub, The optical receptacle includes a plurality of optical receptacles, a plurality of through holes, and a holder for fixing a rear end portion of the fiber stub through each of the through holes.

  A plurality of the optical receptacles are arranged in parallel, and a rear end portion of a fiber stub included in the optical receptacle is exposed and fixed from the holder.

  Further, the end surface of the rear end portion of the fiber stub is formed into a slope shape.

  Further, the inclined shape provided on the end surface of the rear end portion of the fiber stub included in the plurality of optical receptacles is formed in the same direction.

  A housing holding the lens at a position facing the end surface of the rear end of the fiber stub of the multiple optical receptacle according to any one of claims 1 to 4, and a housing fixed to the holder, and a lid for the housing An optical element is provided on a stem serving as a body.

  According to the multiple-type optical receptacle of the present invention, a plurality of optical receptacles are arranged, a plurality of through holes are provided, and a holder for fixing the rear end portion of the fiber stub with each of the through holes. Therefore, it is possible to fix the ferrules of each of the plurality of optical receptacles with a plurality of through-holes with one holder, not only for transmission and reception, so each optical receptacle can be attached to a multi-core optical connector plug ferrule. Can be placed and fixed with high accuracy. As a result, connection loss due to misalignment of the fiber stub of each optical receptacle and the plug ferrule for multi-core optical connector can be prevented, and the number of parts can be reduced, so that a low-cost optical receptacle can be provided. .

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view showing an embodiment of a multiple optical receptacle 8 of the present invention. In the following embodiments, a multiple-type optical receptacle constituted by two reception and transmission optical receptacles will be described.

  First, the sleeve 4 is fitted into the tip of each fiber stub 1 that holds the optical fiber 2 inserted and fixed to each ferrule 1a used for reception and transmission. On the other hand, in order to fix the respective fiber stubs 1 at the same time, a metal holder 3 in which a plurality of through holes into which the fiber stubs 1 are inserted and formed is formed in parallel. Then, the fiber stubs 1 provided with the sleeves 4 are arranged in parallel to each other, and the rear end portions of the fiber stubs 1 are press-fitted and fixed to the through holes of the holder 3, respectively. Composed. Here, the fiber stubs 1 fixed by the through holes of the holder 3 are arranged according to the interval between the multi-core optical connector plug ferrules 6. Further, if a cover 5 made of stainless steel or resin having excellent rust prevention properties is provided along the outer periphery of the sleeve 4 by fitting, bonding, or a combination of both, optical coupling with the sleeve 4 and the plug ferrule 6 is possible. It becomes possible to protect the part. The rear end portion of each fiber stub 1 is obliquely polished in the same direction. Here, the distal end portion of the fiber stub 1 is an end portion on the side to which the optical connector plug ferrule 6 is connected, and is a portion in contact with the sleeve 4. On the other hand, the rear end portion of the fiber stub 1 is an end portion that is optically coupled to the optical element 21, and the portion fixed by the through hole of the holder 3 and the fiber stub 1 of the holder 3 as described later. When exposed from the end face on the side where the optical element 21 is optically coupled, the exposed portion is also included.

  By adopting the above-described configuration, it is possible to prevent relative positional deviation of each optical receptacle, and to arrange and fix a plurality of optical receptacles with high accuracy. Thereby, it is possible to prevent connection loss due to misalignment between the fiber stub 1 of each optical receptacle and the plug ferrule for a multi-core optical connector.

The ferrule constituting the fiber stub 1 is made of a metal such as stainless steel or phosphor bronze, an epoxy, a plastic such as a liquid crystal polymer, or a ceramic such as alumina or zirconia, and is preferably formed of zirconia ceramic. Specifically, partial stabilization mainly comprising tetragonal crystals, containing ZrO ₂ as a main component, at least one of Y ₂ O ₃ , CaO, MgO, CeO ₂ , Dy ₂ O _{3 and the} like as a stabilizer. It is preferable to use zirconia ceramics, and such partially stabilized zirconia ceramics have excellent wear resistance and are appropriately elastically deformed. Therefore, when press-fitting into the sleeve 4 or the through hole of the holder 3, It is advantageous.

  As the ferrule processing method, first, when the ferrule is formed from, for example, zirconia ceramics, a cylindrical or rectangular parallelepiped shaped body that becomes the ferrule 2 is obtained in advance by a predetermined molding method such as injection molding, press molding, extrusion molding, or the like. Thereafter, the molded body is fired at 1300 to 1500 ° C. and subjected to cutting or polishing to a predetermined dimension. Note that a predetermined shape may be formed in advance on the formed body by cutting or the like, and then fired.

  The end face of the fiber stub 1 connected to the plug ferrule 6 of the optical connector, that is, the end face of the tip of the fiber stub 1 is a curved fiber stub having a curvature radius of about 5 to 30 mm in order to reduce connection loss with the optical connector. 1 is mirror-polished perpendicularly to the axial direction of 1, while the other end face, that is, the end face of the rear end portion of the fiber stub 1 is reflected by the end face of the optical fiber 2 by the light emitted from the optical element such as an LD. In order to prevent the reflected light returning to the surface, it is mirror-polished to an inclined surface of about 4 to 10 °. FIG. 2 is a cross-sectional view of an optical module using the multiple optical receptacle of the present invention as viewed from the lateral direction. The end surface of the rear end portion of the fiber stub 1 on the optical element 21 side is polished to 4 to 10 ° in an inclined shape to prevent reflected return light. On the other hand, in order to realize high coupling, it is necessary to couple the optical axis of the optical element 21 with an inclination in the same direction with respect to the oblique polishing direction. Therefore, the lens 25 is shifted with respect to the chip 22 that receives and emits light. It is realized by fixing it. As a result, the optical element 21 is adjusted and fixed with respect to the optical receptacle 8 while being shifted in the direction of the top of the oblique polishing. In other words, if the rear end portions of all the fiber stubs 1 can be polished in the same direction, the deviation of the direction of the apex of the above-described oblique polishing of each optical element 21 to be fixed can be matched. High accuracy can be achieved.

  Therefore, in the present invention, it is preferable that the rear end portion of each fiber stub 1 included in the plurality of optical receptacles 8 is exposed from the holder 3 and fixed. Thus, if it is set as the structure fixed in the state exposed so that the rear-end part of each fiber stub 1 might protrude from the end surface of the holder 3, it is the same surface direction in the state fixed to the holder 3 without shaving the holder 3 It is possible to polish the end faces of each fiber stub 1 at the same time, and with the simplification of the polishing process, the angle of polishing and the polishing direction of each fiber stub can be matched with high precision. The positioning accuracy of each optical element 21 to be fixed can be increased. In addition, as for the length exposed from the holder 3, it is desirable to expose 0.05 mm or more of the shortest distance of the grinding | polishing surface of the rear end part of the fiber stub 1 and the holder 3. FIG. Further, for example, if both ends of each fiber stub 1 are structured to be exposed from both end surfaces of the through holes of the holder 3, each ferrule 1a is first press-fitted and fixed to the holder 3, and the inner holes of the respective ferrules 1a are fixed. After manufacturing the fiber stub 1 to which the fiber 2 is bonded and fixed, both end surfaces of the fiber stub 1 can be simultaneously polished without polishing the holder 3, and the optical fiber 2 is bonded to the inner hole of the ferrule 1a. Since the fiber stub 1 is fixed and polished at both ends, it is less likely to be scratched at the end face during press-fitting as compared to the process of press-fitting to the holder 3, and also occurs on the fiber 2 and the bonded portion. It is possible to relieve the stress that occurs and to suppress the occurrence of microcracks.

  In addition, since the holder 3 is often welded to the optical element 21 (see FIG. 2) as an optical module, materials that can be welded such as stainless steel, copper, iron, nickel, etc. are good, mainly corrosion resistance and weldability. In consideration of the above, stainless steel is used and is manufactured by cutting. Furthermore, the holder 3 is subjected to hole processing such as drilling to form a through hole for holding the fiber stub 1. In addition, the holder 3 is required to have a sufficient fixing strength because the load is continuously applied by the spring pressure on the plug ferrule 6 side when the plug ferrule 6 is repeatedly attached to and detached from the fiber stub 1 and connected. For this reason, the fiber stub 1 may be fixed to the through hole of the holder 3 only by press-fitting. However, in order to firmly fix the fiber stub 1 and the holder 3, a fixing method using bonding or press-fitting and bonding together is used. It may be used.

  The sleeve 4 is preferably made of a material such as zirconia, alumina, or copper and slit into a cylinder. It is often made of a ceramic material such as zirconia, mainly considering wear resistance. As a processing method thereof, for example, when forming with a ceramic material such as zirconia, a cylindrical or columnar molded body that becomes the sleeve 4 is obtained in advance by a predetermined molding method such as injection molding, press molding, or extrusion molding. The molded body is fired at 1300 to 1500 ° C. and subjected to cutting or polishing to a predetermined dimension. In addition, the surface roughness of the inner diameter of the sleeve 4 is preferably an arithmetic average roughness (Ra) of 0.2 μm or less in consideration of the insertability, and the tolerance of the outer diameter of the fiber stub 1 and the inner diameter of the sleeve 4 is to obtain a low connection loss. The inner diameter of the sleeve 4 is designed to be slightly smaller than the outer diameter of the fiber stub 1 and the ferrule 6 so that the insertion force is 0.98 N or more in order to securely hold the fiber stub 1. It is desirable to do. The sleeve 4 may be a simple cylinder that is about +1 μm larger than the outermost diameter of the fiber stub 1 or the ferrule 6. A simple cylindrical sleeve 4 integrally formed with the cover 5 may be used as it is.

  In addition, the cover 5 is made of stainless steel injection-molded for corrosion resistance, or an insulator such as plastic, zirconia, or alumina is used to avoid the influence of static electricity or electromagnetic noise. The sleeves 4 are larger and smaller than the sleeves 4 to prevent them from coming out, and the sleeves 4 are surrounded by larger inner diameters than the sleeves 4. On the other hand, it is fixed by press-fitting, adhesion or combined use.

  Thus, by using the multiple optical receptacle 8, conventionally, it is necessary to position each receptacle 8 with high accuracy with respect to the receptacle 8. Therefore, as shown in FIG. Although there was a problem that the mounting part of the housing 31 had to be made highly accurate, only one holder 3 or cover 5 is required, and not only the number of parts can be reduced, but also each fiber stub 1 is fixed. Since the positioning can be performed only with the positional accuracy of the through hole, it is possible to prevent a connection loss due to a positional shift between each fiber stub 1 of the multiple-type optical receptacle 8 and each plug ferrule 6 of the optical connector.

  Further, the housing 25 is fixed to the holder 3 of the above-described multiple-type optical receptacle by the number of optical receptacles, and the lens 25 is attached by a support member that the housing 25 has at a position facing the end face of the rear end portion of each fiber stub 1. An optical module is provided by holding the optical element 21 on the stem 23 serving as a lid of the casing 25 and sealing the casing 25 with the stem 23 so that the optical element 21 faces the lens 25. 30 can be made.

  Embodiments of the multiple optical receptacle of the present invention will be described below.

  As an embodiment of the present invention, a duplex optical receptacle 8 for reception and transmission shown in FIG. 1 was produced. The optical connector connected to the optical receptacle 7 was an LC connector. The ferrule 1a of the fiber stub 1 is made of zirconia. A cylindrical ceramic molded body is obtained by extrusion molding, and is baked and hardened in a firing process, and is cut.

  On the other hand, the holder 3 was manufactured by cutting with SUS304 having excellent rust prevention and weldability. Furthermore, the holder 3 was drilled to form two through holes at intervals of 6.25 mm.

  Next, with a hand press with a pressure sensor in the through-hole of the holder 3 formed by the above manufacturing method, confirm the sufficient load on the rear end portions of the two cylindrical ferrules of the same length manufactured by the above manufacturing method. While pressing, it was fixed. At this time, the press-fit strength near the fixed position was both about 100 N, and each cylindrical ceramic would not move if the load was less than that. Therefore, it was sufficiently strong against the pressure applied by the plug ferrule 6 and the impact during attachment / detachment. It can be said that there is. Here, the rear end portions of the two ferrules 1a are press-fitted and fixed at a position exposed by 0.05 mm from the end surface of the holder 3 on the side where the optical element 21 is optically coupled. And the fiber stub 1 was produced by inserting and fixing the optical fiber 2 to the inner hole of the ferrule 1a. The end surface of the tip of each fiber stub 1 located on the plug ferrule 6 side is mirror-polished to a curved surface having a radius of curvature of about 20 mm perpendicular to the axis of the fiber stub 1, and the rear end surface of the fiber stub 1 is LD or the like. In order to prevent the light emitted from the optical element 2 from being reflected at the tip of the optical fiber 2 and returning to the optical element, each end face is simultaneously mirror-polished into an 8 ° slope shape to align the two. Fistub 1 was used.

  Next, the sleeve 4 is made of zirconia ceramics, a cylindrical molded body that becomes the sleeve 4 is obtained by a predetermined molding method such as extrusion molding, and is baked and hardened in a firing process, and an outer shape and a slit are processed by a cutting process. Was prepared by polishing. The two slit-containing sleeves 4 thus obtained are press-fitted into the end portions of the respective fiber stubs 1 and fixed. Then, a double-type optical receptacle 8 was manufactured by bonding and fixing a cover 5 integrally formed of plastic as an insulator to prevent the sleeve 4 fitted in each fiber stub 1 from coming off.

  In the duplex optical receptacle 8 manufactured as described above, the fiber stubs 1 arranged in parallel can be easily positioned with the same accuracy as the interval between the through holes formed in the holder 3, and with respect to the optical receptacle, Since positioning of the two-core plug ferrule 6 becomes easy, an optical connector in which the connection loss due to misalignment of the fiber stub 1 of each optical receptacle and the plug ferrule for a multi-core optical connector can be efficiently reduced can be obtained. .

  Furthermore, the number of parts required for manufacturing a dual-type optical receptacle is six points: two fiber stubs 1, one holder 3, two sleeves 4, and one cover 5. On the other hand, the number of parts when using the conventional optical receptor of FIG. 4 as shown in FIG. 5 is 8 for fiber stub 1, 2 for holder 3, 2 for sleeve 4, and 2 for cover 5. Therefore, the number of parts can be reduced by the amount of the holder 3 and the cover 5, and the optical stub 1 can be arranged with high accuracy without depending on the accuracy of the housing 31 for fixing the optical receptacle 8. .

1 shows a cross-sectional view of an optical receptacle of the present invention. Sectional drawing seen from the optical module side using the optical receptacle of this invention is shown. FIG. 3 is a cross-sectional view of a method for fixing a transceiver of an optical module using the optical receptacle of the present invention. Sectional drawing of the optical module using the optical receptacle of a conventional structure is shown. FIG. 6 is a cross-sectional view of a conventional method for fixing a transceiver of an optical module.

Explanation of symbols

1: fiber stub 1a: ferrule 2: fiber 3: holder 4: sleeve 5: cover 6: plug ferrule 7: fiber 8: optical receptacle 8a: transmitting optical receptacle 8b: receiving optical receptacle 21: optical element 22: chip 23 : Stem 24: Housing 25: Lens 30: Optical module 31: Housing 31a: Groove

Claims (5)

An optical receptacle comprising a fiber stub that holds an optical fiber in an inner hole of a ferrule and a sleeve that holds the tip of the fiber stub, wherein a plurality of the optical receptacles are arranged and a plurality of through holes are provided. And a holder for fixing a rear end portion of the fiber stub through each of the through-holes. The multiple optical receptacle according to claim 1, wherein a plurality of the optical receptacles are arranged in parallel, and a rear end portion of a fiber stub included in the optical receptacle is exposed and fixed from the holder. The multiple-type optical receptacle according to claim 1 or 2, wherein an end surface of a rear end portion of the fiber stub has a slope shape. 4. The multiple-type optical receptacle according to claim 3, wherein a slope shape provided on an end face of a rear end portion of the fiber stub included in the plurality of optical receptacles is formed in the same direction. A housing holding the lens at a position facing the end surface of the rear end of the fiber stub of the multiple optical receptacle according to any one of claims 1 to 4, and a housing fixed to the holder, and a lid for the housing An optical module characterized in that an optical element is provided on a stem as a body.

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