JP5414568B2 - Optical component with optical element and optical receptacle with optical element using the same - Google Patents

Description

  The present invention relates to an optical component with an optical element provided with an optical element having a porcelain optical effect used for optical communication and the like, and an optical receptacle with an optical element using the same.

  Conventionally, an optical element such as an optical isolator using a Faraday rotator may be used for a module for optical communication in which a semiconductor element such as a semiconductor laser element or a semiconductor light receiving element is incorporated. Semiconductor laser diodes (hereinafter also referred to as LDs) reflect the light emitted from them and enter the active layer again. The oscillation state is disturbed, the output power varies, the wavelength shifts, etc., and the output signal deteriorates. It is because there is a case to do.

  The optical isolator includes an optical isolator element in which polarizers 51 and 52 are arranged before and after the Faraday rotator 50. FIG. 8A shows an example of an optical isolator element. The forward light incident from the left direction is transmitted by the first polarizer 51 with linearly polarized light having a specific polarization direction (the vertical direction indicated by the broken arrow in FIG. 8A). The direction of polarization of this linearly polarized light is rotated by 45 degrees clockwise with respect to the traveling direction of light by the Faraday rotator 50 and is incident on the second polarizer 52. Since the polarization direction of the second polarizer 52 is set at an angle of 45 degrees clockwise with respect to the polarization direction of the first polarizer 51, the light passes through the second polarizer 52 while maintaining the polarization direction. To Penetrate. On the other hand, as shown in FIG. 8B, the reverse direction light returning from the right direction is transmitted through the linearly polarized light component of the polarization direction of the second polarizer 52, and the polarization direction of the Faraday rotator 50 is 45 degrees. Rotated to be horizontally polarized. The polarized light in the horizontal direction forms an angle of 90 degrees with the polarization direction of the first polarizer 51 and is blocked by the first polarizer 51. A magnet for applying a magnetic field to the Faraday rotator is usually disposed around the optical isolator element.

  FIG. 9 shows an example of a receptacle 70 with an optical element using such an optical isolator as an optical element (see, for example, Patent Document 1). The receptacle 70 with an optical element includes a ferrule 71 in which an optical fiber 73 is inserted. One end surface 72 of the ferrule 71 is provided with an optical isolator element 75 as an optical element so as to block the optical path 74, and a magnet 76 is disposed around the optical isolator element 75. Due to the magnetic field applied by the magnet 76, the Faraday rotator in the optical isolator element 75 rotates the polarization plane of the optical signal and blocks the return light to the semiconductor laser.

  Note that the other end surface 77 of the ferrule 71 is subjected to spherical processing and is brought into contact with the connector. The other end surface side of the ferrule 71 is inserted into a sleeve 78, and the sleeve 78 is housed in a sleeve case 80. The sleeve case 80 is fixed to the holder 79 by an adhesive or press-fitting. Further, one end surface 72 side of the ferrule 71 is fixed to the holder 79 by an adhesive or press-fitting.

Japanese Patent Laid-Open No. 10-133146

However, the optical element-equipped optical receptacle 70 including the optical element 75 having the magneto-optical effect as described above needs to arrange a magnet 76 around the optical element 75. Therefore, the assembly process becomes complicated. For example, when the optical element 75 is attached while adjusting the optical characteristics after the magnet 76 is installed, the previously installed magnet 76 becomes an obstacle, and the optical element 75 is attached. It can be difficult. Furthermore, although the magnet 76 is bonded to the end surface 72 of the ferrule 71 with an adhesive or low-melting glass, there may be a problem that the magnet 76 is peeled off from the ferrule 71.

  In addition, since a space for installing the magnet 76 is required, there is a problem in downsizing the optical receptacle 70 with an optical element.

In view of the above problems, an optical component-equipped optical component according to an embodiment of the present invention has an optical path for propagating an optical signal therein, and is embedded by integrally firing a magnet around the optical path. A cylindrical member made of ceramics, and an optical element having a magneto-optical effect, which is installed on an end surface provided so as to cross the optical path of the cylindrical member.

  The optical path may be an optical fiber held in the pore.

  Further, the end surface may be one end surface of a cylinder.

  The end surface may be a bottom surface of a hole provided on one end surface of the cylinder and wider than the inner diameter of the optical path.

  Further, the end surface may be a bottom surface of a groove provided on one end surface of the tube and extending from the outer peripheral surface of the tube to the outer peripheral surface facing across the optical path.

  Further, the groove may be formed such that a depth of the bottom surface portion that crosses the optical path is shallower than an outer peripheral surface side of the groove.

  The end surface may be an inner wall surface of a groove provided so as to cross the middle of the optical path.

  An optical receptacle with an optical element according to an embodiment of the present invention is a ferrule in which the optical component with an optical element connects optical fibers to each other, and a holder for holding the ferrule and one end of the ferrule with an optical element And a sleeve into which the other end of the ferrule with an optical element is inserted.

  A cylindrical member having an optical path for propagating an optical signal inside, and a magnet embedded in the periphery of the optical path, and an end face provided so as to cross the optical path of the cylindrical member, the magneto-optical effect Since the optical element is installed on the end face of the cylindrical member, there is no need for a space for arranging a separate magnet around the optical element. It can be set as the optical component with an optical element which can express an effect. This simplifies the assembly process of the optical element. Further, since the magnet is embedded in the cylindrical member, the magnet is not peeled off or dropped off from the cylindrical member, and the reliability becomes high. Furthermore, it becomes possible to reduce the size of the optical receptacle with an optical element.

It is sectional drawing which shows an example of embodiment of the optical component with an optical element of this invention. It is sectional drawing which shows the example of other embodiment of the optical component with an optical element of this invention. It is sectional drawing which shows the example of other embodiment of the optical component with an optical element of this invention. It is sectional drawing which shows the example of other embodiment of the optical component with an optical element of this invention. It is a front view which shows the example of other embodiment of the optical component with an optical element of this invention. It is AA sectional drawing in the example of embodiment of FIG. It is sectional drawing which shows an example of embodiment of the optical receptacle with an optical element of this invention. (A), (b) is a perspective view for demonstrating operation | movement of an optical isolator, respectively. It is sectional drawing which shows the conventional optical receptacle with an optical element.

  Hereinafter, each example of an embodiment of the present invention will be described with reference to the drawings.

  The optical component with an optical element of the present invention includes a cylindrical member formed in a cylindrical shape having pores in the axial direction, and an optical element having a magneto-optical effect. For example, an optical fiber or the like is disposed in the pore to form an optical path through which an optical signal propagates, and a magnet is embedded in a cylindrical member around the optical path. An optical element is disposed on the end surface of the cylindrical member, and a magnet is embedded in the cylindrical member near the end surface. The optical element exhibits a magneto-optical effect by the magnetic field generated by the magnet. The cylindrical member is formed of a portion in which more than half of the main portion supports the optical path. A magnet is embedded near the end face, and an optical element is disposed on the end face.

  Hereinafter, as a representative example, a case where the cylindrical member is the ferrule 10 that connects and connects optical fibers in a coaxial position, and the optical components with optical elements are the ferrules 20 and 30 with optical elements will be described. However, the present invention is not limited to these ferrules 20 and 30 with optical elements.

  As shown in FIG. 1, the ferrule 20 with an optical element according to an embodiment of the present invention includes a cylindrical ferrule 10 and an optical element 21 attached to the ferrule 10. The ferrule 10 has an optical path 11 for propagating an optical signal therein, and a magnet 12 is embedded in the ferrule 10 around the optical path 11. An optical element 21 is installed on an end face provided across the optical path 11 of the ferrule 10, for example, the end face 13. In the example of FIG. 1, the optical path 11 is formed of, for example, an optical fiber inserted into the inner hole of the ferrule 10. The magnet 12 is embedded or built in the vicinity of the end face 13 and the optical path 11, and the optical element 21 having a magneto-optical effect functions by the magnetic field generated by the magnet 12. The end surface 13 is formed to be a surface orthogonal to the optical path 11 or an inclined surface inclined with respect to this orthogonal surface in order to prevent return light due to end surface reflection.

  The optical element 21 is installed on the end surface of the ferrule 10 by being bonded to the end surface 13 with, for example, an adhesive or low melting point glass. The optical element 21 has a magneto-optic effect. For example, in the case of an optical isolator element, the optical element 21 has a function of blocking reflected reflected light by being installed on the end face 13 and applying a magnetic field by the magnet 12. . The optical isolator element is manufactured, for example, by sandwiching a Faraday rotator made of a rare earth iron garnet crystal between a first polarizer and a second polarizer and bonding them with an adhesive or low-melting glass.

The optical element 21 is not limited to an optical isolator element. For example, an element that combines a Faraday rotator and a reflecting member, is used for a Faraday rotation mirror, an optical circulator, or the like, and a combination of a birefringent prism and a Faraday rotator is employed. You can also. Thereby, the ferrule 20 with an optical element having various functions utilizing the magneto-optical effect can be provided. For example, when incorporated in an optical fiber sensor or the like by using a Faraday rotating mirror, a Michelson interferometer is configured to have a sensing function to avoid fluctuations in output interference fringes and signal disappearance, and a birefringent prism. By using an element combined with a Faraday rotator, a functional component for optical communication having a function as an optical path changing device such as a polarization-independent optical isolator or an optical circulator can be provided.

As the material of the ferrule 10, zirconium oxide (zirconia) ceramics, aluminum oxide (alumina) ceramics, mullite ceramics, silicon nitride ceramics, silicon carbide ceramics, and aluminum nitride ceramics are used alone or mainly. Examples thereof include ceramics contained as components and glass ceramics such as crystallized glass. Among them, zirconia-based ceramics (ceramics containing zirconia as a main component) excellent in weather resistance and toughness are preferable. Among zirconia-based ceramics, in particular, at least one selected from the group consisting of zirconium oxide (ZrO ₂ ) as a main component and Y ₂ O ₃ , CaO, MgO, CeO ₂ , Dy ₂ O _{3 and the} like is used as a stabilizer. Partially stabilized zirconia ceramics (mainly tetragonal crystals) are included as a more preferable material from the viewpoints of wear resistance and elastic deformation. In addition, resin or metal may be used.

  Examples of the magnet 12 built in the ferrule 10 include permanent magnets such as alnico magnets, ferrite magnets, neodymium magnets, and other rare earth magnets. Since it is heated to the sintering temperature of ceramics, a ferrite magnet having a relatively high melting point is most suitable. For example, a MnZn ferrite magnet, which is a type of ferrite magnet, starts sintering at about 1000 ° C. and melts when it exceeds about 1600 ° C. Sintering can be performed at a sintering temperature of 1500 ° C., whereby the MnZn ferrite magnet does not melt and zirconia ceramics can be sintered in a shape-retained state. Since simultaneous firing with zirconia ceramics can be performed, when forming the ferrule 10 with a built-in magnet, it is also possible to insert a ferrite magnet after press molding. Since the firing temperature varies depending on the sinterability of the raw materials and the addition of a sintering aid, it is necessary to select a magnet in accordance with the firing temperature of each porcelain.

  It is preferable that the distance between the optical element 21 and the magnet 12 is a minimum distance, for example, 3 mm or less, so that a strong magnetic field is applied to the optical element 21 provided on the end face 13. However, it is preferable that the magnet 12 is embedded directly under the end face 13 inside the ferrule 10 and embedded so as not to be exposed on the surface of the ferrule 10. For example, in the case of the ferrule 10, the end face 13, the outer periphery 15, and the optical path 11 outer peripheral portion are formed of ceramics having excellent corrosion resistance, so that corrosion does not easily proceed even when used in a bad environment such as high temperature and high humidity. The dimensions do not change and a highly accurate fit can be maintained. Since the magnet 12 is embedded in the ferrule 10, the magnet 12 is not detached and high reliability is obtained. Further, the assembly process of the external magnet can be simplified, and the space required for the external magnet is not required.

  Here, a method by press molding using ceramics will be described as an example of a manufacturing method of the ferrule 20 with an optical element incorporating a magnet.

First, a granular ceramic raw material to which a binder has been added by a spray drying method is partially charged into a mold as a first stage raw material charging, and then a cylindrical magnetic material serving as a magnet 12 is charged. Then, as the second stage raw material charging, the ceramic raw material is again charged into the mold so as to cover the magnetic raw material previously charged, and pressed into a state in which the magnetic raw material is buried in the ceramic raw material to form a ferrule 10 Mold. This raw ceramic formed body is degreased and sintered in a firing step. Then, after cooling to a required temperature, it passes through the magnetization process which magnetizes the magnet 12 formed inside. Further, the ferrule 10 is subjected to various surface processing such as grinding and polishing.
Is completed, the optical element 21 is adhered to the portion of the end face 13 that intersects the optical path 11 with an adhesive or low-melting glass to obtain the ferrule 20 with built-in magnet with optical element.

  More specifically, for example, when incorporating a magnet 12 made of MnZn ferrite in a ferrule 10 made of zirconia ceramic, a binder is added to a zirconia primary material to form a slurry, and a zirconia ceramic raw material for press molding is produced by spray drying. To do. Next, a zirconia ceramic raw material is put into a mold, a magnetic material is put in, a zirconia ceramic raw material is put in again, and then pressed to form. The magnetic substance introduced at this time is obtained by calcining the raw materials of iron oxide, Mn compound, and Zn compound at 1300 ° C., pulverizing with a ball mill or the like, and press-molding in a state where a magnetic field is applied. is there. The molded body of zirconia ferrule containing the magnetic body is degreased and fired in an atmospheric furnace, and zirconia ceramics are sintered together with the internal magnetic body at a maximum temperature of about 1300 ° C. After firing, various processes such as concentric processing, outer periphery grinding, and end surface spherical processing are performed, and the resultant is put into a magnetizing apparatus, and a high pulse magnetic field is applied to magnetize the internal MnZn ferrite. Regarding the MnZn ferrite magnet, since the firing process is performed simultaneously with the firing of the zirconia ceramics, the manufacturing cost can be reduced.

  In the above example, the case where the magnetic material is one layer and the magnet 12 is formed is taken up. However, by increasing the number of times the ceramic raw material and the magnetic material are alternately inserted, the optical material composed of the multilayer magnet 12 is used. The element-equipped magnet built-in ferrule 20 can also be manufactured, which is effective when a groove or the like is provided in the ferrule and an optical element is disposed there. Further, instead of the magnet 12 that continuously makes a round around the optical path 11, it may be divided. Furthermore, by performing stepwise raw material input, production by injection molding or casting is also possible. Further, when the ferrule 20 is formed of resin or the like, it can be manufactured similarly.

  In the example of the above embodiment, the optical element 21 is installed on the one end surface 13 of the ferrule 10 and the magnet 12 is disposed near the end surface 13. However, the present invention is not limited to this. By selecting the arrangement of the magnets 12, it is possible to provide ferrules with optical elements each having a characteristic. Some examples of these are as follows.

  For example, like the ferrule 30 with a built-in magnet with an optical element shown in FIG. 2, the groove 16 is provided on the outer peripheral surface of the ferrule 10 so as to divide the middle of the optical path 11 of the ferrule 10, and the optical element 21 is placed in the groove 16. It is good also as a form with which it is equipped. In this case, the magnet 12 is arranged around the optical path 11 inside the inner wall surface 16a on one side of the groove 16 or inside the inner wall surfaces 16a, 16b on both sides so that a magnetic field can be applied to the optical element 21 in the central groove 16. It is buried around If the optical element 21 installed in the groove 16 is an optical isolator element and the thickness is about 700 μm, the groove 16 having a width of, for example, 800 μm is processed by a dicing saw, and the inner wall surfaces 16a and 16b of the groove are formed. The optical element 21 is fixed with an adhesive or low-melting glass so as to be connected to the opening optical path 11. In the case of this example, a ferrule 10 is used in which a magnetic material is arranged and molded according to the position where the groove 16 of the ferrule 10 is processed, and is fired and magnetized.

  3 shows a cross-sectional view of the ferrule 10 having a shape having a groove 16 so as to divide the middle of the optical path 11 in the center as in FIG. In this example, the magnet 12 is disposed so as to be embedded in the bottom portion 16 c around the optical path 11 formed in the groove 16. Also in this case, a strong magnetic field can be applied from a portion close to the optical element 21. In the case of this example, when forming the ferrule 10, the magnetic material is formed so that the magnetic material material is arranged in the planned processing portion of the groove 16, fired and magnetized, and then a part of the magnet 12 is removed with a dicing saw. It can be manufactured by machining the groove 16. In this case, since strict dimensional accuracy is not required for the bottom portion 16c of the groove 16, the surface of the magnet 12 may be exposed from the bottom portion 16c.

  In the case of such a ferrule 30 with an optical element, since the optical paths 11 on both sides of the groove 16 divided by the groove 16 are arranged in a straight line, the loss caused by the positional deviation of these optical paths 11 can be reduced. Therefore, it can be set as the ferrule 30 with an optical element with little insertion loss.

  4 is a cross-sectional view showing an example in which a hole 17 having an opening width larger than the diameter of the optical path 11 is provided in one end surface 13 of the ferrule 20 with an optical element shown in FIG. FIG. In this case, the magnet 12 may be disposed inside the bottom surface 17 a of the hole 17, but may be disposed inside the inner peripheral surface 17 b of the hole 17 surrounding the optical element 21. This is advantageous when a uniform magnetic field needs to be applied inside the relatively thick optical element 21. Further, since the optical element 21 is disposed inside the hole 17, if the formation position of the hole 17 with respect to the optical path 11 is accurately processed, the installation position of the optical element 21 can be made accurate.

  5 and 6 show an embodiment in which workability in end face polishing is considered while taking advantage of the shape shown in FIG. FIG. 5 is a front view of the ferrule 20 with an optical element as viewed from the axial direction, and FIG. 6 is a cross-sectional view of the AA plane shown in FIG.

  A groove 18 is cut in the end surface 13 so as to cross the optical path 11 from the outer peripheral surface 15 to the opposing outer peripheral surface 15, and the optical element 21 is disposed on the bottom surface of the groove 18. The magnet 12 is embedded in the ferrule 11 on the side of the groove 18, for example. Needless to say, the magnet 12 may be built inside the bottom surface of the groove 18. When the magnet 12 built in the ferrule 11 is located near the side surface of the optical element 21, it is necessary to apply a uniform magnetic field inside the optical element 21 or the like that is relatively thick (long in the axial direction of the ferrule). Is advantageous. Further, since the optical element 21 is disposed in the groove 18, if the formation position and width of the groove 18 with respect to the optical path 11 are accurately processed, the installation position of the optical element 21 can be made accurate. .

  Further, the groove 18 for installing the optical element 21 is preferably formed at a diameter position passing through the central axis from the outer peripheral surface 15 of the end surface 13 to the opposing outer peripheral surface. Such a groove 18 can be easily formed by passing a grinder or the like with diamond abrasive grains. It can also be formed by press molding. By using the groove 18, it becomes easy to smoothly polish the bottom surface 18a on which the optical element 21 is installed, and the workability is improved.

  Further, the depth of the groove 18, that is, the axial length of the ferrule 10 from the one end surface 13 of the ferrule 10 to the bottom surfaces 18 a and 18 b of the groove 18 is greater than the bottom surface 18 b of the groove 18 on the outer peripheral 15 surface side. It is preferable that the bottom surface 18a of the portion to be installed is made shallow. As a result, the smooth polished surface of the bottom surface 18a can be reduced, so that the consumption of the tool is reduced and the working time is shortened.

  Next, FIG. 7 is a cross-sectional view showing an optical receptacle 40 with an optical element using the ferrule 20 with an optical element shown in FIG. 1 as an example. In the optical receptacle 40 with an optical element, a ferrule 10 including an optical fiber 41 in the optical path 11 and having a magnet 12 built around the optical path 11 on the one end face 13 side is used as a so-called fiber stub. One end side of the ferrule 10 is fixed to the holder 43 by press-fitting or bonding, and an optical element 21 is provided on one end surface 13 of the ferrule 10 to form a ferrule 20 with an optical element. The other end side of the ferrule 10 is fitted with a sleeve 45 so as to be inserted into a through hole of the sleeve 45, and the sleeve 45 is protected by a sleeve case 44 covered on the outer side. One end side of the sleeve case 44 is fixed by being press-fitted or bonded to the holder 43. A cylindrical precision sleeve is basically used as the sleeve 45, but a split sleeve with a slit may be used as necessary.

  Since the holder 43 is often welded to the case as an optical module, materials that can be welded, such as stainless steel, copper and its alloys, and iron-nickel alloys, can be mentioned. In consideration of the stainless steel, it is preferably used.

  A wide range of materials such as stainless steel, copper and its alloys, iron and its alloys, nickel alloys, plastics, zirconia ceramics, and alumina ceramics are used for the sleeve case 44.

  The sleeve 45 is made of zirconia ceramics, alumina ceramics, copper and alloys thereof, stainless steel, or the like, and zirconia ceramics is preferable in consideration of wear resistance.

  According to the optical receptacle 40 with an optical element according to an embodiment of the present invention, the end surface 13 only includes the optical element 21, the holder 43 can be designed to be small, and the optical receptacle 40 with an optical element can be downsized. This contributes to downsizing of the entire optical module.

  The present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the scope of the present invention. For example, in the above-described embodiment, an example in which one optical path 11 is formed in the cylindrical ferrule 10 is shown. However, a configuration having a plurality of optical paths 11 may be used, and magnets 12 are provided around these optical paths 11. It is also possible to arrange and provide an optical element on the end face 13.

  In the description of the above embodiment, the terms “upper, lower, left and right” are merely used to describe the positional relationship in the drawings, and do not mean the positional relationship in actual use.

10: Ferrule 11: Optical path 12: Magnet 13: End face 16: Groove 17: Hole 18: Groove 20, 30: Ferrule with optical element 21: Optical element 40: Optical receptacle with optical element 43: Holder 44: Sleeve case 45: Sleeve

Claims (8)

A cylindrical member made of ceramics having an optical path for propagating an optical signal therein and embedded by firing a magnet integrally around the optical path, and provided so as to cross the optical path of the cylindrical member An optical component with an optical element, comprising: an optical element that is installed on the end face and has a magneto-optical effect. The optical component with an optical element according to claim 1, wherein the optical path is an optical fiber held in a pore. The optical component-equipped optical component according to claim 1, wherein the end surface is one end surface of a cylinder. 3. The optical component-equipped optical component according to claim 1, wherein the end surface is a bottom surface of a hole that is provided on one end surface of the cylinder and is wider than an inner diameter of the optical path. The said end surface is a bottom face of the groove | channel provided in the one end surface of a pipe | tube, and was provided from the outer peripheral surface of the said pipe | tube to the outer peripheral surface which crosses the said optical path and opposes. Optical components with optical elements. 6. The optical component with an optical element according to claim 5, wherein the groove is formed so that a depth of the bottom surface portion crossing the optical path is shallower than an outer peripheral surface side of the groove. 3. The optical component with an optical element according to claim 1, wherein the end surface is an inner wall surface of a groove provided so as to cross the middle of the optical path. The optical component with an optical element according to any one of claims 1 to 7 is a ferrule that connects optical fibers in a pore, the ferrule, a holder that holds one end of the ferrule with an optical element, and An optical receptacle with an optical element, comprising: a sleeve into which the other end of the ferrule with an optical element is inserted; and a sleeve case.

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