JP5253543B2 - Optical receptacle and optical module - Google Patents

Description

  The present invention relates to an optical receptacle and an optical module, and more particularly to an optical receptacle and an optical module for optical communication.

  Conventionally, an optical module for converting an optical signal into, for example, an electric signal has been developed. Such an optical module includes an optical element such as a semiconductor laser or a photodiode and an optical fiber for conducting an optical signal. The optical element is disposed opposite to the end face of the optical fiber so that the optical signal is incident on the end face. The optical signal is introduced or derived through an optical fiber by (or exiting from the end face).

  In optical communication using an optical module, with an increase in the amount of information transmitted and received, there is an increasing demand for an increase in the transmission speed of optical signals. However, in order to increase the transmission speed of an optical signal, it is necessary to reduce the influence of interference noise (noise). Therefore, an optical receptacle configured to reduce the influence of noise has been developed and is publicly known (see, for example, Patent Document 1).

  FIG. 5 shows a cross section of a conventional noise reducing optical receptacle 70. The optical receptacle 70 includes a fiber stub 71, a sleeve 72, a resin sleeve case 73, and a metal holder 74. The fiber stub 71 is obtained by adhering and fixing one end of an optical fiber (not shown) for conducting an optical signal to the through hole of the ferrule 75. The sleeve 72 is for obtaining alignment between the optical fiber of the plug (not shown) and the optical fiber of the fiber stub 71. The sleeve case 73 is for protecting the sleeve 72, and has a locking portion 73a for locking to a convex portion 74a of a holder 74 described later. The holder 74 is for holding the fiber stub 71 and the sleeve case 73, and has a convex portion 74a projecting in the radial direction on the outer periphery thereof.

  In the optical receptacle 70 having such a configuration, the sleeve case 73 is made of resin. Therefore, since the ratio of the optical receptacle 70 made of metal (a material that is relatively susceptible to noise) can be reduced, the influence of noise can be reduced.

JP 2001-66468 A

However, since the optical receptacle 70 is assembled by engaging the engaging portion 73a of the sleeve case 73 with the convex portion 74a of the holder 74, sufficient mechanical strength between the sleeve case 73 and the holder 74 can be obtained. I can't. As a means for sufficiently securing the mechanical strength between the sleeve case 73 and the holder 74, for example, it is conceivable to increase the height of the convex portion 74a to increase the locking region with the locking portion 73a. Increasing the height of the convex portion 74a increases the amount of deformation of the sleeve case 73. When the amount of deformation increases and excessive deformation stress is applied to the sleeve case 73, damage such as microcracks may occur in the sleeve case 73 itself. When a microcrack is generated, the degree of cracking progresses in an environment such as a mechanical test such as a vibration test or an impact test, a high-temperature and high-humidity test, or a temperature cycle test that is defined by a standard such as Telcordia. Therefore, the optical receptacle 70 cannot obtain sufficient durability, and as a result, it is difficult to obtain sufficient long-term reliability.

  In addition, the above-described assembly (engagement of the engaging portion 73a with respect to the convex portion 74a) is performed by elastic deformation of the resin sleeve case 73. However, since the elastic deformation is not complete elastic deformation, The dimension of the sleeve case 73 is difficult to return to the dimension before assembly. That is, it is difficult to obtain high dimensional accuracy in the optical receptacle 70. Note that the smaller the optical receptacle 70 is, the greater the influence due to the decrease in dimensional accuracy.

  The present invention has been conceived under such circumstances, and is capable of reducing the influence of noise, and has a high dimensional accuracy optical receptacle and optical module excellent in mechanical strength or long-term reliability. The purpose is to provide

Optical receptacle of the present invention has an optical fiber, and is optically connected to the plug having an optical fiber, the formed Ru fiber stub of insulating material, at least at least a portion and said fiber stub of the plug A sleeve having a through hole for inserting a part thereof; a sleeve case for accommodating at least a part of the sleeve; and a holder for holding the fiber stub. It has a holding portion having a function of holding the outer peripheral surface of the sleeve casing has a holding portion for holding a part of the outer peripheral surface of the fiber stub, spaced from each other and the holder and the sleeve casing ing.

Preferably, the cross section, the holder-side side surface of the sleeve casing, a shape reduced in diameter toward the front Symbol Sleeve case in the direction of the holder.

Preferably, the side surface of the holder on the sleeve case side in a cross-sectional view has a shape that decreases in diameter from the sleeve case toward the holder.

The optical module of the present invention, the optical receptacle of the present invention, emits light toward the optical fiber of the fiber stub, or an optical element for receiving the light derived through the optical fiber of said fiber stub Is provided.

Optical receptacle of the present invention, the holder has a holding portion responsible for the holding function of the previous SL fiber stub, sleeve case has a holding portion for holding a portion of the fiber stub, the holder and the sleeve casing Since the one end side and the other end side of the fiber stub are held apart from each other, the current flowing from the sleeve case toward the holder does not reach the holder.

  In addition, when the side surface of the joint portion on the holding portion side has a shape that decreases in diameter as it moves away from the sleeve case when viewed in cross section, a large laser welding surface of the holder can be secured, and welding can be performed easily. It becomes. Further, when the sleeve case and the fiber stub are press-fitted and held, the holding portion can be secured long, so that the fiber stub is not held obliquely with respect to the axis of the sleeve case. If the fiber stub is held at an angle with respect to the axis of the sleeve case, the axis of the sleeve inserted and fixed along the axis of the fiber stub is also inclined, and the sleeve may come into contact with the sleeve case. In the state where the sleeve is in contact with the sleeve case, the optical fiber tip surface of the plug and the fiber optic tip surface of the fiber stub are not directly joined, and light loss occurs.

The optical module of the present invention employs the optical receptacle of the present invention. Therefore, in this optical module, even if current flows from the sleeve case to the holder, the sleeve case and the holder are separated from each other, so that no current flows through the holder, and an IC for driving the LD and PD is provided. It will not be destroyed.

It is sectional drawing showing the optical receptacle which concerns on reference embodiment of this invention. It is sectional drawing showing the optical module which employ | adopted the optical receptacle shown in FIG. It is sectional drawing showing the optical receptacle which concerns on embodiment of this invention. It is sectional drawing showing the optical module which employ | adopted the optical receptacle shown in FIG. It is sectional drawing showing the conventional optical receptacle.

FIG. 1 shows a cross section of the optical receptacle X. The optical receptacle X includes a fiber stub 10, a sleeve 20, a sleeve case 30, and a holder 40. Note that the plug 50 in FIG. 1 is obtained by inserting one end of an optical fiber 52 into a through hole extending in the axial direction (arrow AB direction) of a ferrule 51 for a plug and bonding and fixing with an adhesive, for example. .

  The fiber stub 10 includes a fiber stub ferrule 11 and an optical fiber 12, and the optical fiber 12 is inserted into a through-hole extending in the axial direction (arrow AB direction) of the ferrule 11, and bonded and fixed by, for example, an adhesive. It is a member constituted by doing. The fiber stub 10 is optically connected to the plug 50. The tip surface 10a of the fiber stub 10 is a round surface (for example, a curvature radius of 5 to 30 mm). Such a configuration is suitable for reducing the connection loss with the plug 50. The rear end surface 10 b of the fiber stub 10 is an inclined surface that is inclined at a predetermined angle (for example, 4 to 10 °) with respect to the axial center of the fiber stub 10. Such a configuration is suitable, for example, for preventing light emitted from an optical element (such as an LED or LD) from being reflected by the end face of the optical fiber 12 and returning to the optical element as reflected light.

The ferrule 11 is a member that protects the optical fiber 12 and contributes to increase the concentricity between the fiber stub 10 and the plug 50 in cooperation with a sleeve 20 described later. Ferrule 11 is made of a material such as zirconium oxide (zirconia), aluminum oxide (alumina), mullite, silicon nitride, silicon carbide, aluminum nitride, or the like, ceramics containing these as main components, or glass ceramics such as crystallized glass. Metals such as phosphor bronze, beryllium copper, brass, and stainless steel, plastics such as epoxy and liquid crystal polymer, etc. Among them, zirconia-based ceramics (ceramics mainly composed of zirconia) excellent in weather resistance and toughness are preferable. It is. Further, among zirconia ceramics, zirconium oxide (ZrO ₂ ) is the main component, and at least one selected from the group consisting of Y ₂ O ₃ , CaO, MgO, CeO ₂ , Dy ₂ O _{3 and the} like is used as a stabilizer. The partially stabilized zirconia ceramics (mainly tetragonal crystals) are preferred from the viewpoints of wear resistance and elastic deformation.

  The optical fiber 12 is for conducting (propagating) light. Examples of the optical fiber 12 include a silica-based optical fiber, a plastic-based optical fiber, and a multicomponent glass-based optical fiber.

The sleeve 20 has a through hole 21 into which the fiber stub 10 and the plug 50 are inserted, and is a member responsible for the alignment function between the fiber stub 10 and the plug 50. The fiber stub 10 is inserted into the sleeve 20 through the open end 21a, and the plug 50 is inserted through the open end 21b. The sleeve 20 according to the present embodiment is a so-called split sleeve having a slit (not shown) extending in the longitudinal direction (arrow AB direction). When the sleeve 20 having such a configuration is employed, the hole diameter of the through hole 21 is slightly smaller than the outer diameter of the plug (for example, the through hole) in order to increase the gripping force acting on the plug 50 inserted into the sleeve 20. The pressure acting on the fiber stub 10 when the fiber stub 10 is inserted into the fiber stub 10 is preferably set to 0.98 N or more. As the sleeve 20, a so-called precision sleeve (no slit) may be employed instead of the split sleeve. Examples of the material constituting the sleeve 20 include the same materials as those of the ferrule 11 described above.

  The sleeve case 30 is an approximately cylindrical member that has an opening 30 a and a joint 30 b and accommodates the sleeve 20. The diameter of the space for accommodating the sleeve 20 in the sleeve case 30 is configured to be slightly larger (for example, 60 μm) than the outer diameter of the sleeve 20. The opening 30a is a part for guiding the plug 50 when the plug 50 is inserted, and has a tapered shape. The opening diameter of the opening 30 a is configured to be slightly larger (for example, 0.2 mm) than the outer diameter of the plug 50. The joint 30 b is a part for joining to the holder 40. The material constituting the sleeve case 30 includes synthetic resin (such as thermoplastic resin and thermosetting resin), metal (such as stainless steel, copper, iron and nickel), ceramics (such as aluminum oxide (alumina) and zirconium oxide (zirconia)). ), Glass (such as quartz), and the like. Among them, a thermoplastic resin is preferable from the viewpoint of insulation and fusion properties. Examples of the thermoplastic resin include nylon resin, liquid crystal polymer resin, polyacetal resin, polybutylene terephthalate resin, polyetherimide resin, and polycarbonate resin, and examples of the thermosetting resin include epoxy resin and urea resin. In addition, fillers such as glass fibers and glass particles may be added to the sleeve case 30 in order to increase mechanical strength. In the sleeve case 30, for example, the constituent material of the joint portion 30b and the constituent material of other portions are made different so that the joint portion 30b is made of a thermosetting resin and the other portions are made of metal. May be.

  The holder 40 has a first part 41 and a second part 42 and is a member for holding the fiber stub 10. The first portion 41 has a joining portion 41a that joins the sleeve case 30 and is configured so that the sleeve case 30 can be joined. Examples of the material constituting the first portion 41 include the same materials as those of the sleeve case 30 described above. The second portion 42 has a holding portion 42a that performs the holding function of the fiber stub 10, and is configured so that the fiber stub 10 can be fitted. The arithmetic average roughness of the contact surface of the holding portion 42 a with the fiber stub 10 is preferably set to 0.1 μm or more from the viewpoint of the stability of the holding state of the fiber stub 10. Examples of the material constituting the second portion 42 include metals (stainless steel, copper, iron, nickel, and the like), ceramics (alumina, zirconia, and the like), and stainless steel is preferable from the viewpoint of corrosion resistance and weldability. . Furthermore, the outer surface may be subjected to a plating treatment (for example, gold plating) from the viewpoint of adhesion with the solder.

  The sleeve case 30 and the holder 40 are joined by adhesion or fusion. In the case of bonding by bonding, the sleeve case 30 and the holder 40 are bonded by press-bonding with an adhesive (not shown) interposed between the bonding portion 30b and the bonding portion 41a. As an adhesive, from the viewpoint of ensuring sufficient bonding strength, UV curable epoxy resin, thermosetting epoxy resin, UV and thermosetting epoxy resin, UV curable acrylic resin, thermosetting acrylic resin, UV curable polyimide resin And thermosetting polyimide resin. In the case of joining by fusion, the sleeve case 30 and the holder 40 are brought into contact by bringing the joining portion 30b and the joining portion 41a into contact with each other and applying heat (thermal fusion), ultrasonic waves (ultrasonic fusion), or the like. Bonding with is realized.

In the optical receptacle X according to the present embodiment, the joint portion 41a of the holder 40 is configured by an insulating member. Therefore, in the optical receptacle X, the ratio of the metal part (part comprised by the metal) which occupies for this optical receptacle X can be reduced. In particular, when the holding portion 42a of the holder 40 is made of ceramics, the proportion of the metal portion in the optical receptacle X can be further reduced. Therefore, in the optical receptacle X, the metal portion that becomes a noise receiving portion (antenna) can be reduced, so that the influence of noise received from the surroundings can be reduced.

  Further, in the optical receptacle X, the joint portion 30b of the sleeve case 30 and the joint portion 41a of the holder 40 are joined by adhesion or fusion with an adhesive. Therefore, in the optical receptacle X, the mechanical strength between the sleeve case 30 and the holder 40 can be sufficiently ensured. Therefore, for example, the mechanical strength such as the vibration test and the impact test defined by the standards such as Telcordia. Sufficient durability can be obtained even in environments such as tests, high-temperature and high-humidity tests, and temperature cycle tests. That is, sufficient long-term reliability can be obtained with the optical receptacle X.

  Further, in the optical receptacle X, the sleeve case 30 can be joined to the holder 40 while the sleeve case 30 is aligned. Therefore, in the optical receptacle X, high dimensional accuracy can be obtained.

FIG. 2 shows a cross section of an optical module Y provided with an optical receptacle X. The optical module Y includes an optical receptacle X and an optical element unit 60. The optical element unit 60 includes an optical element 61, a lens 62, and a case 63.

  The optical element 61 is a light emitting element for emitting light toward the optical fiber of the fiber stub 10 or a light receiving element for receiving the light derived through the optical fiber of the fiber stub 10. Examples of the light emitting element include light emitting diodes such as semiconductor lasers and LEDs, and examples of the light receiving element include a receiving PD (photodiode).

  The lens 62 has a function of condensing the light emitted from the light emitting element when the optical element 61 is a light emitting element and introducing the light into the optical fiber of the fiber stub 10, and the fiber stub when the optical element 61 is a light receiving element. It is a member that bears the function of condensing light introduced through 10 optical fibers and introducing it into the light receiving element.

  The case 63 is a member for housing the optical element 61 and the lens 62, and is joined to the optical receptacle X by, for example, welding. Examples of the material constituting the case 63 include weldable materials such as stainless steel, copper, iron, and nickel, and stainless steel is preferable from the viewpoint of corrosion resistance and weldability.

  FIG. 3 shows a cross section of the optical receptacle V according to the embodiment of the present invention. The optical receptacle V includes a fiber stub 10, a sleeve 20, a sleeve case 30, and a holder 40.

  The sleeve case 30 is disposed so as to cover the sleeve, and plays a role of holding a part of the fiber stub 10. Since the sleeve case and the holder are separated and electrically insulated, the constituent material may be metal.

  The holder 40 is a member for holding the fiber stub 10. Examples of the constituent material include metals (stainless steel, copper, iron, nickel, etc.), ceramics (alumina, zirconia, etc.), etc. Among them, stainless steel is preferable from the viewpoint of corrosion resistance and weldability. is there. Furthermore, the outer surface may be subjected to a plating treatment (for example, gold plating) from the viewpoint of adhesion with the solder.

FIG. 4 shows a cross section of an optical module W provided with an optical receptacle V according to the present invention. The optical module W includes an optical receptacle X and an optical element unit 60. The optical element unit 60 includes an optical element 61, a lens 62, and a case 63.

  As described above, since the sleeve case 30 of the optical receptacle V and the holder 40 are separated from each other, current flowing from the sleeve case 30 toward the holder 40 does not flow through the holder 40 and the case 63, and the PD The IC that drives the optical element 61 such as LD and LD is not destroyed.

  Although specific embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  The optical receptacle and the optical module may have an optical isolator on the rear end face 10 b side of the fiber stub 10 to suppress light returning to the light source for emitting light toward the fiber stub 10.

  Next, examples and comparative examples of the present invention will be described.

  <Fabrication of Optical Receptacle X Shown in FIG. 1> First, a fiber stub was fabricated by bonding and fixing an optical fiber to a through-hole of a ferrule made of zirconia ceramics. The fiber stub has an edge surface (curvature radius: 20 mm) at its front end surface and an inclined surface (inclination angle: 6 °) at its rear end surface. Next, a holder was prepared by cutting the stainless steel to create a holder holding portion, and providing a joining portion made of polyetherimide on the holding portion by insert molding. Next, the rear end side of the ferrule in the manufactured fiber stub was press-fitted into the holder of the manufactured holder. Next, the end portion side of the fiber stub pressed into the holder was inserted into the through-hole of the split sleeve made of zirconia from one end side. The constituent material of the sleeve was zirconia ceramics. Next, the joining part of the sleeve case and the joining part of the holder were joined by ultrasonic fusion so as to cover the sleeve into which a part of the fiber stub was inserted. The constituent material of the sleeve case was polyetherimide resin. In this manner, ten optical receptacles according to this example were produced.

  <Fabrication of Optical Receptacle V shown in FIG. 3> First, a fiber stub was fabricated by adhesively fixing an optical fiber to a through-hole of a ferrule made of zirconia ceramics. The fiber stub has an edge surface (curvature radius: 20 mm) at its front end surface and an inclined surface (inclination angle: 6 °) at its rear end surface. Next, the rear end side of the ferrule in the manufactured fiber stub was press-fitted into the holder. The constituent material of the holder was stainless steel. Next, the end portion side of the fiber stub pressed into the holder was inserted into the through hole of the split sleeve made of zirconia ceramics from one end side. The constituent material of the sleeve was zirconia ceramics. Next, the sleeve case and the fiber stub were press-fitted and fixed so as to cover the sleeve into which a part of the fiber stub was inserted. The constituent material of the sleeve case was stainless steel. Thus, ten optical receptacles according to this comparative example were produced.

  <Initial test> A tensile tester (trade name) with respect to the sleeve case in a state where the holders of the optical receptacles (5 pieces) of the present embodiment as prepared are fixed to a predetermined jig by YAG welding. : Autograph AGS-500A, manufactured by Shimadzu Corporation). And the tensile load when the optical receptacle was destroyed was measured, and the result was shown in Table 1 with the average value.

<High-temperature and high-humidity test> The optical receptacles (5) of this example were left in a high-temperature and high-humidity tester for 1000 hours under conditions of a temperature of 85 ° C. and a humidity of 85%, and then the optical receptacles (5 In a state where the holders were fixed to a predetermined jig by YAG welding, a tensile load was applied to the sleeve case by a tensile tester (trade name: Autograph AGS-500A, manufactured by Shimadzu Corporation). And the tensile load when the optical receptacle was destroyed was measured, and the result was shown in Table 1 with the average value.

[Comparative example]
<Fabrication of optical receptacle> First, a fiber stub was fabricated by adhering and fixing an optical fiber to a through-hole of a ferrule made of zirconia ceramics. The fiber stub has an edge surface (curvature radius: 20 mm) at its front end surface and an inclined surface (inclination angle: 6 °) at its rear end surface. Next, the rear end side of the ferrule in the manufactured fiber stub was press-fitted into the holder. The constituent material of the holder was stainless steel. On the outer periphery of the holder, a convex portion was formed over the entire circumference in the circumferential direction, and the protruding height was 0.3 mm. Next, the end portion side of the fiber stub pressed into the holder was inserted into the through hole of the split sleeve made of zirconia ceramics from one end side. The constituent material of the sleeve was zirconia ceramics. Next, the locking portion of the sleeve case having a locking portion that can be locked to the convex portion of the holder is locked to the convex portion of the holder so as to cover the sleeve into which a part of the fiber stub is inserted. . The constituent material of the sleeve case was polyetherimide resin. Thus, ten optical receptacles according to this comparative example were produced.

  <Initial test> A tensile tester (trade name) with respect to the sleeve case in a state where the holders of the optical receptacles (5) of this comparative example in the as-made state are fixed to a predetermined jig by YAG welding. : Autograph AGS-500A, manufactured by Shimadzu Corporation). And the tensile load when the optical receptacle was destroyed was measured, and the result was shown in Table 1 with the average value.

  <High-temperature and high-humidity test> The optical receptacles (5) of this comparative example were left in a high-temperature and high-humidity tester for 1000 hours under the conditions of a temperature of 85 ° C. and a humidity of 85%, and then the optical receptacles (5 In a state where the holders were fixed to a predetermined jig by YAG welding, a tensile load was applied to the sleeve case by a tensile tester (trade name: Autograph AGS-500A, manufactured by Shimadzu Corporation). And the tensile load when the optical receptacle was destroyed was measured, and the result was shown in Table 1 with the average value.

  <Evaluation> As shown in Table 1, in the optical receptacle X shown in FIG. 1 of the example, the strength between the sleeve case and the holder is almost the same as the initial state (about 120 N) even after the high temperature and high humidity test. In contrast, in the optical receptacle of the comparative example, the strength between the sleeve case and the holder was reduced by about 30% from the initial state after the high temperature and high humidity test. Further, the initial state intensity of the optical receptacle X of the example is about 20% larger than the initial state intensity of the optical receptacle of the comparative example. Further, the initial state intensity of the optical receptacle V shown in FIG. 3 of the embodiment is about five times larger than the initial state intensity of the optical receptacle of the comparative example. From the above, it is considered that the optical receptacle of the example is superior in mechanical strength or long-term reliability as compared with the optical receptacle of the comparative example.

X Optical receptacle V Optical receptacle 10 Fiber stub 12 Optical fiber 20 Sleeve 30 Sleeve case 40 Holder 41a Joining portion 42a Holding portion 50 Plug 52 Optical fiber

Claims (4)

Has an optical fiber, and is optically connected to the plug having an optical fiber, the formed Ru fiber stub of insulating material,
A sleeve having a through hole for inserting at least a part of the plug and at least a part of the fiber stub;
A sleeve case for accommodating at least a part of the sleeve;
A holder for holding the fiber stub,
The holder has a holding portion having a function of holding the outer peripheral surface of the fiber stub,
The sleeve case has a holding portion that holds a part of the outer peripheral surface of the fiber stub,
The optical receptacle is characterized in that the holder and the sleeve case are separated from each other. 3. The optical receptacle according to claim 1, wherein a side surface of the sleeve case on the holder side has a shape whose diameter is reduced from the sleeve case toward the holder in a cross-sectional view. 2. The optical receptacle according to claim 1, wherein the side surface of the holder on the sleeve case side has a shape that decreases in diameter from the sleeve case toward the holder in a cross-sectional view. The optical receptacle according to any one of claims 1 to 3,
An optical module comprising: an optical element that emits light toward the optical fiber of the fiber stub or receives light derived through the optical fiber of the fiber stub.

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