JP4672488B2 - Optical module - Google Patents

Description

The present invention relates to an optical module, and more particularly to 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 module is configured to introduce or derive the optical signal through the optical fiber by placing the optical element opposite to the end surface of the optical fiber and allowing the optical signal to enter (or exit from) the end surface. Has been.

  FIG. 4 is a cross-sectional view showing an optical module 103 provided with an optical receptacle 101 according to the prior art. The conventional optical receptacle 101 includes a fiber stub 110, a sleeve 120, a metal sleeve case 130, and a metal holder 140.

  In the optical receptacle 101, the rear end portion of the fiber stub 110 obtained by inserting and fixing the optical fiber 112 made of quartz glass or the like into the through hole of the ferrule 111 made of a ceramic material such as zirconia or alumina is made of a metal holder. It is press-fitted into 140 and fixed. On the other hand, the distal end portion is inserted into the inner hole of the sleeve 120, and a sleeve case 130 for protecting the sleeve 120 is fixed by being press-fitted or adhered to the holder 140.

  Furthermore, when the optical module 103 is configured using the optical receptacle 101 described above, a metal housing 163 including an optical element 161 and a lens 162 is provided on the rear end surface side of the optical receptacle 101 including the fiber stub 110. It is possible to exchange optical signals by joining by welding and inserting the plug ferrule 151 into the inner hole of the sleeve 120 from the front end surface side of the optical receptacle 101 and bringing the end surface of the optical fiber 152 into contact.

  In the optical module 103, when the optical isolator element 165 is used for the purpose of preventing reflected return light incident on the light source, the optical isolator element 165 is fixed to the rear end of the fiber stub 110 of the optical receptacle 101, The magnet 166 is joined to the end face of the holder 140, and the optical isolator element 165 is arranged in the through hole of the magnet 166 (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 2005-233587

  In optical communication using an optical module, with an increase in the amount of information transmitted and received, there are increasing demands for downsizing the optical module and increasing the transmission speed of optical signals.

  In the conventional optical receptacle 101, the holder 140 is made of metal, and is joined to the housing 163 including the optical element 161 and the lens 162 by welding. In the case of an LD module, the housing 163 is generally connected to the circuit ground or power supply, and the entire receptacle has the same potential as the circuit ground or power supply, so the receptacle itself is on the circuit ground or power supply. There is a problem of radiating noise radio waves (noise). Further, in the case of the PD module, there is a problem that metal parts such as the sleeve case 130 and the holder 140 receive a noise radio wave (noise) as a receiving part (antenna) and the reception sensitivity is deteriorated. In particular, the higher the transmission speed, the wider the band is required. However, due to the mixing of accurate electrical signals and noise radio waves (noise), the reception sensitivity is significantly degraded, and the optical signal speed is increased. It becomes difficult. Further, when the LD module and the PD module are arranged close to each other for the purpose of reducing the size of the optical module 103, noise radio waves (noise) generated from the receptacle of the LD module are directly received by the metal part of the PD module, There is a problem that it is easily affected by noise radio waves (noise).

  In order to solve the above problem, it is conceivable that the receptacle and the casing are made of a non-metallic material such as resin or ceramics, but in this case, since the receptacle and the casing cannot be joined by welding or soldering, It is necessary to perform bonding by adhesion or the like. However, when bonding is performed by bonding or the like, the adhesive is weak in humidity and the bonding strength deteriorates with time, so that there is a problem in long-term reliability of bonding strength. In addition, the gas generated from the adhesive affects the driving stability of the optical element, which has a problem of poor long-term reliability.

  Further, in the conventional optical receptacle 101, a surge current jumps from the optical connector to be inserted into the metal portion of the optical receptacle 101, and the surge current is transmitted from the metal portion to the housing 163, and finally the circuit portion of the module or There is also a problem that the optical element 161 is reached and the circuit portion and the optical element 161 are destroyed by the surge current.

  On the other hand, when an optical circuit is formed using the optical receptacle 101, the optical receptacle 101 is fixed by joining a metal housing 147 and a holder 140. Here, in order to prevent the generation of the noise radio wave, in the optical receptacle 101 in which the holder 140 is made of an insulating material, for example, resin or ceramic, the difference in the thermal expansion coefficient between the holder 140 and the housing 147 is large. It is difficult to form a strong bond between the housing 147 and the optical receptacle 101.

  Accordingly, an object of the present invention is to provide an optical receptacle and an optical module that reduce the influence of noise and are excellent in long-term reliability of bonding strength.

An optical module according to claim 1 of the present invention includes:
A fiber stub with optical fibers;
And electrically insulating holder having a through hole for holding one end of the fiber stub,
A bonding member provided on at least part of the outer surface of said holder,
An optical element for emitting light toward the optical fiber of the fiber stub, or for receiving light derived through the optical fiber of the fiber stub;
A housing which is joined to the holder via the joining member and accommodates the optical element;
It is characterized by providing.

In the optical module according to claim 2 of the present invention, the joining member is characterized by that name a ring shape.

The optical module according to claim 3 of the present invention is characterized in that the joining member is press-fitted and fixed to the holder.

In the optical module according to claim 4 of the present invention, the joining member is characterized in that it extends to the end surface of the rear end side of the holder.

The optical module according to claim 5 of the present invention is characterized in that the joining member is made of metal.

In the optical module according to claim 6 of the present invention, the holder is characterized in ceramic Tona Rukoto.

  In the optical receptacle of the present invention, a joining member is provided on at least a part of the outer surface of the holder made of an electrically insulating material. As a result, in the optical receptacle, it is possible to reduce a conductive portion that becomes a noise receiving portion (antenna), and thus it is possible to reduce the influence of noise received from the surroundings. Even if a surge current is generated by inserting and removing the plug, since the holder is made of an electrically insulating material, propagation of the surge current to the circuit portion of the module and the optical element can be suppressed. As a result, in the optical receptacle of the present invention, it is possible to prevent the module circuit and the optical element from being destroyed by the surge current. Furthermore, in the optical receptacle of the present invention, since the joining member is provided on the outer surface of the holder, the joining member and the housing can be firmly joined and fixed by, for example, laser welding, solder, and an adhesive. Become.

  Moreover, the joining member of the optical receptacle of the present invention has a ring shape that is inserted into the holder. By comprising in this way, a joining member can be arrange | positioned easily and cheaply on the outer surface of a holder, and an assembly is also easy.

  Further, the joining member inserted into the holder is press-fitted and fixed to the holder. By comprising in this way, a joining member can be arrange | positioned easily and cheaply on the outer surface of a holder, and it is suitable for raising the joining strength between a holder and a joining member. Therefore, sufficient durability can be obtained even in harsh test environments such as mechanical tests such as vibration tests and impact tests specified by standards such as Telcordia, high temperature and high humidity tests, and temperature cycle tests. It is done. That is, an optical receptacle having sufficient long-term reliability can be obtained.

  Furthermore, the joining member of the optical receptacle of the present invention extends to the end surface on the rear end side of the holder. By comprising in this way, the end surface of the housing of an optical element unit and the end surface of the holder of an optical receptacle can be joined directly, without using a housing. As a result, since the optical receptacle and the optical element unit can be easily joined, the assembly of the optical module can be simplified.

  Furthermore, the joining member of the optical receptacle of the present invention is made of metal. By comprising in this way, it becomes possible to join and fix a joining member and a housing more firmly, for example with laser welding and solder.

  Furthermore, the electrically insulating holder of the optical receptacle of the present invention is made of ceramics. With this configuration, when providing a sleeve case for protecting the sleeve, for example, a sleeve case made of metal or ceramic can be easily and firmly joined and fixed by press-fitting the sleeve case into the holder.

  In the optical module of the present invention, the above-described optical receptacle is used. Therefore, in the optical module of the present invention, since the conductive portion that becomes the noise receiving portion (antenna) can be reduced, the influence of noise received from the surroundings can be reduced, and the long-term reliability of the bonding strength can be reduced. Is excellent.

  FIG. 1 shows a cross section of an optical receptacle 1 according to an embodiment of the present invention. The optical receptacle 1 includes a fiber stub 10, a sleeve 20, a sleeve case 30, and a holder 40. In the plug 50 shown on the left side of FIG. 1, one end of the optical fiber 52 is inserted into the through hole extending in the axial direction (longitudinal direction) of the plug ferrule 51, and, for example, an adhesive is used. Adhesive fixed.

  The fiber stub 10 is a substantially cylindrical member in which an optical fiber 12 is inserted into a through hole extending in the axial center direction (longitudinal direction) of a fiber stub ferrule 11 and is bonded and fixed, for example, with an adhesive. . In addition, the fiber stub 10 is optically connected to the plug 50 disposed to face the fiber stub 10. 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 face 10 b of the fiber stub 10 is inclined at a predetermined angle (for example, 4 to 10 °) with respect to the axis 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. As a material constituting the ferrule 11, zirconium oxide (zirconia), aluminum oxide (alumina), mullite, silicon nitride, silicon carbide, aluminum nitride and the like, ceramics containing these as main components, and glass ceramics such as crystallized glass Metals such as phosphor bronze, beryllium copper, brass, and stainless steel, and plastics such as epoxy and liquid crystal polymer are used, and zirconia-based ceramics (ceramics mainly composed of zirconia) with excellent weather resistance and toughness are particularly suitable. is there. Further, among zirconia ceramics, zirconium oxide (ZrO ₂ ) as a 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 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. As the optical fiber 12, a quartz optical fiber, a plastic optical fiber, a multicomponent glass optical fiber, or the like is used.

  The sleeve 20 having a cylindrical shape has a through hole 21 into which the fiber stub 10 and the plug 50 are inserted, and has a centering function between the fiber stub 10 and the plug 50. The fiber stub 10 is inserted into the sleeve 20 from the open end 21a on the rear side, and the plug 50 is inserted from the open end 21b on the front end side. The sleeve 20 according to the present embodiment is a so-called split sleeve having a slit (not shown) extending in the longitudinal direction. When the split sleeve 20 is used, the hole diameter of the through hole 21 is slightly smaller than the outer diameter of the plug (for example, to the through hole 21) in order to increase the gripping force acting on the plug 50 inserted into the sleeve 20. The pressure applied to the fiber stub 10 when the fiber stub 10 is inserted is preferably set to 0.98 N or more. As the sleeve 20, a so-called precision sleeve (no slit) can be used instead of the split sleeve. A material similar to the ferrule 11 described above is used as the material of the sleeve 20.

  The sleeve case 30 is a substantially cylindrical member for housing the sleeve 20 having an opening 30a on the front end side and a joint 30b on the rear end side. In the sleeve case 30, the inner diameter of the storage space for storing the sleeve 20 is 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 30a is slightly larger than the outer diameter of the plug 50 (for example, 0.2 mm). 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 are used, and a thermoplastic resin is particularly preferable from the viewpoints of electrical insulation and fusion. As the thermoplastic resin, nylon resin, liquid crystal polymer resin, polyacetal resin, polybutylene terephthalate resin, polyetherimide resin, polycarbonate resin, etc. are used, and as the thermosetting resin, epoxy resin, urea resin, etc. are used. . In addition, fillers such as glass fibers and glass particles may be added to the sleeve case 30 in order to increase mechanical strength.

The holder 40 is a member for holding the fiber stub 10 and has a holding portion 42a that bears the holding function of the fiber stub 10, and is configured so that the fiber stub 10 can be fitted. A joining member 45 is provided on at least a part of the outer surface of the holder 40. In order to stably hold the fiber stub 10, the arithmetic average roughness of the contact surface with the fiber stub 10 in the holding portion 42a is preferably set to 0.1 μm or more. Further, a counterbore surface can be provided on the rear end surface of the holder 40 in order to fix the magnet. The outer diameter of the counterbore surface is slightly larger than the outer diameter of the magnet (0.02 to 0.8 mm), and the counterbore depth is about 0.1 to 2 mm. As a material constituting the holder 40, synthetic resin (such as thermoplastic resin and thermosetting resin), ceramics (such as aluminum oxide (alumina) and zirconium oxide (zirconia)), glass (such as quartz), and the like are used. Zirconia-based ceramics (ceramics mainly composed of zirconia) having excellent weather resistance and toughness are suitable. Further, among zirconia ceramics, zirconium oxide (ZrO ₂ ) as a 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 as a stabilizer. The partially stabilized zirconia ceramics (mainly tetragonal crystals) are preferred from the viewpoints of wear resistance and elastic deformation.

  The joining member 45 is a member for joining the housing 63 of the optical element unit 60 and the optical receptacle 1 when the optical module 3 is manufactured. In order to facilitate electrical insulation between the sleeve case 30 and the housing 63 of the optical element unit 60, the joining member 45 is preferably formed not on the entire outer surface of the holder but only on a part of the outer surface. . As a material constituting the joining member 45, a metal material such as stainless steel, copper, iron and nickel is used, and stainless steel materials such as SUS304 and SF20T which are excellent in YAG weldability are particularly suitable.

  The joining member 45 is a ring shape (shown in FIG. 1) that is inserted into the outside of the holder 40, a key shape that is inserted into the outside of the holder 40 (shown in FIG. 2A), or the outside of the holder 40. Metallization (shown in FIG. 2B) having a metal layer formed thereon can be used. Since the YAG welding is generally performed when the optical element unit 60 and the optical receptacle 1 are bonded and fixed when the optical module 3 is formed, the ring shape shown in FIG. 1 is preferable. As a method of fixing the joining member 45 to the holder 40, press-fitting, adhesion, screw fixing, or the like can be used. In particular, press-fitting is preferable from the viewpoint of ease of fixing, fixing strength, and fixing reliability. Further, it is desirable that the joining member 45 extends to the end face on the rear end side (that is, the optical element unit 60 side) so that YAG welding can be performed also at the corner portion of the joining member 45.

  The optical receptacle 1 and the optical element unit 60 can be joined in a direct joining form in which the joining member 45 extending to the end on the rear end side of the holder 45 and the housing 63 are joined directly. Further, as shown in FIG. 3, the optical receptacle 1 and the optical element unit 60 may be joined in an indirect joining form in which the joining member 45 and the casing 63 are joined with a metal housing 47 interposed therebetween. Good. In any case, it is possible to form a strong joint between the optical receptacle 1 and the optical element unit 60 by YAG welding or the like.

  The sleeve case 30 and the holder 40 are fixed by adhesion or press fitting. When fixing with an adhesive, the sleeve case 30 and the holder 40 are fixed by interposing an adhesive (not shown) between the joint 30b and the joint 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 A thermosetting polyimide resin or the like is used.

  The optical receptacle 1 according to the present embodiment includes an electrically insulating member. Therefore, in the optical receptacle 1, the ratio of the electroconductive part (part typically comprised by the metal) which occupies for the optical receptacle 1 can be reduced. Therefore, in the optical receptacle 1, the conductive portion that becomes the 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 1, the joint portion 30b of the sleeve case 30 and the joint portion 41a of the holder 40 are fixed by adhesion or press-fitting with an adhesive. Therefore, since the optical receptacle 1 can sufficiently secure the bonding strength between the sleeve case 30 and the holder 40, 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 harsh test environments such as tests, high-temperature and high-humidity tests, and temperature cycle tests. That is, the optical receptacle 1 having sufficient long-term reliability can be obtained.

  FIG. 3 shows a cross section of an optical module 3 provided with the optical receptacle 1 according to the present invention. The optical module 3 includes an optical receptacle 1 and an optical element unit 60. The optical element unit 60 includes an optical element 61, a lens 62, and a housing 63.

  The optical element 61 is a light emitting element for emitting light toward the optical fiber 12 of the fiber stub 10 or a light receiving element for receiving light derived via the optical fiber 12 of the fiber stub 10. As the light emitting element, a light emitting diode such as a semiconductor laser or LED is used, and as the light receiving element, a receiving PD (photodiode) or the like is used.

  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 12 of the fiber stub 10, and a fiber when the optical element 61 is a light receiving element. It is a member having a function of condensing light introduced through the optical fiber 12 of the stub 10 and introducing it into the light receiving element.

  The housing 63 is a member for housing the optical element 61 and the lens 62, and is bonded and fixed to the optical receptacle 1 by welding, for example. As a material constituting the casing 63, weldable materials such as stainless steel, copper, iron, nickel, and the like can be used, and stainless steel is particularly preferable from the viewpoint of corrosion resistance and weldability.

  The optical receptacle 1 and the optical module 3 may have an optical isolator 65 on the rear end face 10 b side of the fiber stub 10 for suppressing return light to the light source for emitting light toward the fiber stub 10. In that case, the optical isolator element 65 is fixed to the rear end of the fiber stub 10 of the optical receptacle 1, the magnet 66 is fixed to the counterbore surface of the holder 40, and the optical isolator element 65 is disposed in the through hole of the magnet 66. It has become.

  The holder 40 included in the optical receptacle 1 according to the present embodiment is configured to include an electrically insulating material. For this reason, in the optical receptacle 1, a phenomenon in which the magnet 66 is attracted to the counterbore surface of the holder 40 and is not displaced does not occur, so that stable characteristics can be obtained for a long time.

  As mentioned above, although embodiment of this invention was shown, this invention is not limited to this, A various change is possible within the range which does not deviate from the technical idea of this invention.

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

  <Fabrication of Optical Transceiver> 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 holder was produced by carrying out injection molding of the zirconia ceramics and performing cutting and grinding as post-processing. A ring-shaped joining member obtained by cutting stainless steel was press-fitted into the holder. 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 joint part of the sleeve case and the joint part of the holder were fixed by press-fitting 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.

  Further, the obtained optical receptacle is YAG welded to a stainless steel housing provided with a semiconductor laser and a PD (photodiode) for reception and a spherical lens made of quartz glass as an optical element. PD modules were fabricated and these were placed in parallel in a plastic case to fabricate an optical transceiver according to this example.

  <Receiving sensitivity measurement test> A DC power supply (trade name: PAB18-1A, manufactured by KIKUSUI) is attached to the optical transceiver of the present embodiment as it is, so that the module can be driven and a digital data analyzer ( (Trade name: MP1630B, manufactured by Anritsu Corporation) was connected to enable transmission and reception of pulse signals. Further, the LD module and the PD module were connected by a jumper cable having optical connectors arranged at both ends. As a result, the pulse signal transmitted from the digital data analyzer becomes an optical signal via the LD module, and this optical signal is transmitted from the jumper cable having the optical connector at both ends to the PD module and converted into the pulse signal again. Received by the data analyzer.

  Then, the bit error rate with respect to the input optical power of the optical transceiver according to the present embodiment was measured, and the result is shown in FIG.

[Comparative example]
<Fabrication of Optical Transceiver> 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. 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 sleeve case joint and the holder joint were joined by press fitting 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.

  Furthermore, a stainless steel housing having a spherical lens made of a semiconductor laser and a receiving PD (photodiode) as an optical element and a spherical glass is YAG welded to the obtained receptacle, so that an LD module and a PD module are obtained. And these were placed in parallel in a plastic case to produce an optical transceiver according to this comparative example.

  <Receiving sensitivity measurement test> A DC power supply (trade name: PAB18-1A, manufactured by KIKUSUI) is attached to the optical transceiver of this comparative example as it is, so that the module can be driven and a digital data analyzer ( (Trade name: MP1630B, manufactured by Anritsu Corporation) was connected to enable transmission and reception of pulse signals. Further, the LD module and the PD module were connected by a jumper cable having optical connectors arranged at both ends. As a result, the pulse signal transmitted from the digital data analyzer becomes an optical signal via the LD module, and this optical signal is transmitted from the jumper cable having the optical connector at both ends to the PD module and converted into the pulse signal again. Received by the data analyzer.

  Then, the bit error rate with respect to the input optical power of the optical transceiver according to this comparative example was measured, and the result is shown in FIG.

  <Evaluation> As shown in FIG. 5, compared with the optical transceiver of the comparative example, in the optical transceiver of the present invention, the bit error was reduced and the reception sensitivity was improved by about 0.25 dBm. From the above, the optical transceiver of the example was able to reduce the influence of noise received from the surroundings as compared with the optical transceiver of the comparative example.

It is sectional drawing of the optical receptacle which concerns on one Embodiment of this invention. It is sectional drawing which shows other embodiment. It is sectional drawing of the optical module using the optical receptacle shown in FIG. It is sectional drawing of the optical receptacle which concerns on a prior art. It is a figure which shows the measurement result regarding the input optical power and bit error rate in an optical transceiver.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical receptacle 3 Optical module 10 Fiber stub 12 Optical fiber 20 Sleeve 30 Sleeve case 40 Holder 45 Joining member 47 Housing 50 Plug 52 Optical fiber 60 Optical element unit 61 Optical element 63 Case

Claims (6)

A fiber stub with optical fibers;
And electrically insulating holder having a through hole for holding one end of the fiber stub,
A bonding member provided on at least part of the outer surface of said holder,
An optical element for emitting light toward the optical fiber of the fiber stub, or for receiving light derived through the optical fiber of the fiber stub;
A housing which is joined to the holder via the joining member and accommodates the optical element;
An optical module comprising: The joining member is characterized by that name a ring shape, an optical module according to claim 1. The joining member is characterized by being press-fitted into the holder, the optical module according to claim 2. The joining member is characterized in that it extends to the end surface of the rear end side of the holder, the optical module according to any one of claims 1 to 3. The joining member is characterized in that it consists of metal, an optical module according to any one of claims 1 to 4. The holder is characterized in ceramic Tona Rukoto optical module according to any one of claims 1 to 5.

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