JP2009230092A - Optical isolator module and optical element module using the same - Google Patents

Abstract

An optical isolator module and an optical element module are provided that reduce a positional deviation of a polarizer and a Faraday rotator caused by heat generation of the polarizer.
An optical isolator module includes a flat Faraday rotator 12 and a main surface of the Faraday rotator 12 on which light is incident or emitted, and a light incident / exit surface is bonded to each other via an adhesive. An optical isolator element 10 having a first polarizer 11a and a second polarizer 11b, and a cylindrical holding member 32 in which the second polarizer 11b is bonded to one end surface so as to close a through hole through which light is transmitted. And a protective material 25 that covers the Faraday rotator 12 in contact with the outer periphery of the Faraday rotator 12. The protective material 25 includes a resin and has a thermal conductivity as compared with the first polarizer 11a. Is expensive.
[Selection] Figure 1

Description

  The present invention relates to an optical isolator module having an optical isolator that is built in an optical element module such as a transmitter for optical communication and suppresses reflected return light to a light emitting element such as an LD (laser diode), and an optical device mounted with the optical isolator module. The present invention relates to an element module.

  Semiconductor laser modules for optical communication used in long-distance systems are strongly required to have a high output and a high speed and a wide band. Further, in such a semiconductor laser module, an optical isolator is used in order to suppress the return of light to the light source.

  FIG. 6 is a longitudinal sectional view showing a conventional optical isolator module in which an optical isolator is attached to an optical fiber end. The optical isolator module 400 includes an optical isolator unit 200 including an optical isolator element 100 and a magnet 210, a translucent member 150, an optical fiber 310, and a cylindrical body 320.

  The optical isolator element 100 includes polarizers 110a and 110b on the light incident side and light emitting side, and a Faraday rotator 120 interposed therebetween, and a translucent member 150 made of a glass material is provided on the outer surface of the polarizer 110b. The other surface of the translucent member 150 is disposed on the distal end surface 320 a of the cylindrical body 320 so as to cover the end surface of the optical fiber 310.

The magnet 210 having a cylindrical shape is disposed on the outer peripheral portion of the cylindrical body 320 of the optical fiber fixing unit 300 so as to cover the optical isolator element 100 in order to apply a magnetic field to the Faraday rotator 120. Further, the inner peripheral surface of the magnet 210 and the outer peripheral surfaces of the optical isolator element 100 and the translucent member 150 are bonded together by a bonding agent 250 made of low melting point glass or solder.
JP 2006-309190 A

  In the optical isolator module 400, the optical isolator element 100 and the translucent member 150 are bonded to the magnet 210 with a bonding agent 250 made of low-melting glass or solder. Therefore, at the time of bonding, the working temperature is about 200 to 350 ° C. Overheated. Therefore, in the conventional optical isolator module 400, an organic adhesive such as a low heat resistant resin cannot be used as an adhesive for joining the polarizers 110a and 110b and the Faraday rotator 120 constituting the optical isolator element 100. It has been difficult to adjust the polarization directions of the polarizers 110a and 110b on the incident side and the light emission side and fix them at the optimum positions.

  In addition, when high-power LD light having a polarization plane orthogonal to the polarization light transmission direction of the polarizer is incident on the polarizer, the light that is not transmitted is absorbed, and thus the polarizer easily generates heat. The heat generated by the exothermic action deteriorates the adhesive strength of the organic adhesive that joins the polarizer and the Faraday rotator, and the polarizer and the Faraday rotator may be displaced.

  Therefore, the present invention has been devised in view of the above-described problems, and an object of the present invention is to facilitate the assembly of an optical isolator element and to reduce an optical isolator module and an optical device that reduce deterioration caused by heat generation of a polarizer. It is to provide an element module.

  The optical isolator module according to the present invention includes a flat Faraday rotator and a first polarized light in which a light incident / exit surface is bonded to each main surface of the Faraday rotator on which light is incident or emitted via an adhesive. An optical isolator element having a polarizer and a second polarizer, a cylindrical holding member in which the second polarizer is bonded to one end surface so as to close a through hole through which light is transmitted, and the Faraday rotator A protective material covering the Faraday rotator in contact with the outer periphery of the Faraday rotator, wherein the protective material comprises a resin and has a higher thermal conductivity than the first polarizer. And

  In the optical isolator module of the present invention, it is preferable that the protective material is made of a silicone resin containing metal powder.

  Moreover, the optical isolator module of this invention WHEREIN: It is preferable that the said protective material is arrange | positioned between the said Faraday rotator and the said holding member.

  Moreover, the optical isolator module of this invention WHEREIN: It is preferable that the said protective material covers the said 1st polarizer and the said 2nd polarizer in the state which contacted the outer periphery of the said 1st polarizer and the said 2nd polarizer. .

  Further, the optical element module of the present invention further includes a cylindrical magnet arranged to enclose the optical isolator element in the hole, and the protective material is arranged in contact with the inner peripheral surface of the magnet. It is preferable.

  The optical element module of the present invention includes an optical isolator module of the present invention, a cylindrical first holder in which one end of the holding member is inserted and fixed, and a second holder in which the first holder is inserted. A light-emitting element that transmits light toward the through hole of the holding member via the optical isolator element, and a case that houses the light-emitting element and is joined to the second holder. Features.

  In the optical isolator module of the present invention, the outer periphery of the Faraday rotator having a higher thermal conductivity than that of the first polarizer is covered with a protective material having a higher thermal conductivity than that of the first polarizer. Thus, heat is easily released from the protective material to the outside, and the heat dissipation of the optical isolator element can be improved. As a result, in the optical isolator module of the present invention, even if heat is generated in the first polarizer due to absorption of laser light that is different from the transmission axis of the polarizer, the adhesive between the first polarizer and the Faraday rotator. Therefore, reliability can be improved.

  Moreover, since the optical element module of this invention is equipped with the optical isolator module of this invention, it can improve the heat dissipation of a 1st polarizer and can improve reliability.

  Hereinafter, embodiments of an optical isolator module of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view including the central axis of the optical isolator module 40 according to the first embodiment of the present invention. The optical isolator module 40 includes an optical isolator unit 20 including an optical isolator element 10 and a magnet 21, a protective material 25, and an optical fiber fixing unit 30.

  The optical isolator 20 includes an optical isolator element 10 and a cylindrical magnet 21 for applying a magnetic field to the Faraday rotator 12 of the optical isolator element 10. The optical isolator element 10 includes a first polarizer (hereinafter referred to as a polarizer 11a), a second polarizer (hereinafter referred to as a polarizer 11b), and a Faraday rotator 12 interposed therebetween. The optical isolator element 10 includes a light-transmitting organic adhesive (for example, an epoxy resin or an acrylic resin) between the polarizer 11a and the Faraday rotator 12 and between the Faraday rotator 12 and the polarizer 11b. Each element is bonded to each other by an adhesive).

  The Faraday rotator 12 is a member having a function of rotating the polarization direction of incident light by a predetermined angle (Faraday effect) when a predetermined magnetic field is applied, and is made of, for example, a bismuth-substituted garnet crystal. The thickness of the Faraday rotator 12 is set so that, for example, the polarization direction of incident light rotates by 45 °. Further, the Faraday rotator 12 is sufficient if it has a shape having at least two light incident / exit surfaces, and examples thereof include a polygonal shape and a circular flat plate shape. Further, the Faraday rotator 12 is composed of, for example, a bismuth-substituted garnet or YIG garnet added with Tb, Gd, or Ho. Further, the thermal conductivity of the Faraday rotator made of such a material is about 4.0 to 5.0 W / m · K.

  The polarizers 11a and 11b are members for selectively transmitting polarized light of a predetermined angle, and the light transmission polarization angle of the light incident side polarizer 11a and the light transmission polarization of the light output side polarizer 11b. The angle is arranged so as to be shifted by an angle equivalent to the rotation angle at which the polarization direction of the light is rotated by the Faraday rotator 12. That is, if the polarization direction of the light incident on the Faraday rotator 12 is set to rotate by 45 °, the light transmission side polarization direction of the polarizer 11a and the light output side polarizer 11b The light transmission polarization direction is shifted from the light transmission polarization direction by 45 °.

  For the polarizers 11a and 11b, for example, polarizing glass made of soda glass or borosilicate glass is used. Polarized glass is a member having polarization characteristics by arranging metal particles elongated in the glass in one direction, and transmits light having a polarization direction perpendicular to the extending direction of the metal particles. Absorbs light having a polarization direction parallel to the stretching direction. As the glass forming the polarizers 11a and 11b, for example, a glass in which a metal is contained in borosilicate glass can be used. In addition, examples of the shapes of the polarizers 11a and 11b include various shapes such as a flat plate shape, a disk shape, and a wedge shape. Further, when the polarizers 11 a and 11 b are made of the borosilicate glass described above, the thermal conductivity is 0.94 to 1.05 W / m · K, which is smaller than the thermal conductivity of the Faraday rotator 12.

  The light entrance / exit surface of the optical isolator element 10 may be sufficiently larger than the beam spot diameter of the incident light, and may have a size that takes into account the optical axis deviation from the optical fiber 31.

  The magnet 21 is inserted and fixed to the outer peripheral portion of the holding member 32 of the optical fiber terminal 30 so as to cover the optical isolator element 10. In the present embodiment, the magnet 21 is bonded and fixed to the holding member 32, but may be fixed by press-fitting from the viewpoint of improving reliability in a high-temperature and high-humidity environment. Moreover, as a material of the magnet 21, Sm-Co etc. can be used, for example. Further, the thermal conductivity of the magnet 21 is 11 to 12 W / m · K in the case of the above-mentioned material, and is extremely higher than the polarizer 11 a and the Faraday rotator 12.

  The optical fiber terminal 30 includes an optical fiber 31, a cylindrical holding member 32, and a first holder 33.

  The optical fiber 31 is a member for transmitting light. For example, an optical fiber such as a single mode fiber or a multimode fiber can be used, and the optical fiber 31 can be appropriately changed according to the application.

  The holding member 32 has a through hole 32b, and is a member for holding one end of the through hole 32b from which the coating 31a of the optical fiber 31 has been removed via an adhesive. As a material of the holding member 32, for example, zirconium oxide (zirconia), aluminum oxide (alumina), mullite, silicon nitride, silicon carbide, aluminum nitride and the like, ceramics containing these as main components, glass ceramics such as crystallized glass, etc. Among them, zirconia-based ceramics (ceramics mainly composed of zirconia) excellent in weather resistance and toughness are preferable. In the optical isolator element 10, the light exit surface of the light exit side polarizer 11 b is fixed to the distal end surface 32 a of the holding member 32 through, for example, an epoxy adhesive.

  The first holder 33 is a member for holding the holding member 32 by the counterbore portion 33a and fixing the covering portion 31a of the optical fiber 31 by the second through hole 33b communicating with the counterbore portion 33a. It is made. The holding member 32 is press-fitted into the counterbore portion 33a. The 1st holder 33 can be formed, for example with metal members, such as stainless steel and Ni-Fe.

  The protective material 25 is made of resin. As such a resin, for example, a silicone resin or an epoxy resin can be used, and a silicone resin is preferable from the viewpoint of high thermal conductivity. Furthermore, the protective material 25 may contain metal powder from the viewpoint of easily improving the heat dissipation characteristics. Examples of such metal powder include gold, silver, copper, aluminum oxide, and zinc oxide. In particular, the protective material 25 is preferably a silicone resin containing 60 to 90% by weight of an aluminum oxide filler because the thermal conductivity can be increased to 2.0 W / m · K or more.

  Moreover, in the protective material 25, if the mixing ratio of resin and metal powder is 60 to 90 weight% with respect to the whole quantity, while obtaining high thermal conductivity, the moldability of the protective material 25 is maintained. It is preferable from the viewpoint that it can be performed. The thermal conductivity of the protective material 25 can be measured by, for example, a laser flash method. In this laser flash method, laser light is emitted from a laser oscillator and directly applied to the surface of the object to be measured, and the amount of heat and the time emitted from the back surface of the object to be measured are measured to derive the specific heat and thermal diffusivity. The thermal conductivity is calculated.

  On the other hand, as shown in FIG. 1, if the protective material 25 is arranged so as to connect the side surface of the optical isolator element 10 and the inner peripheral surface of the magnet 21, the heat accumulated in the optical isolator element 10 is protected. Since the heat is transmitted to the magnet 21 having a relatively high thermal conductivity via the material 25, the heat dissipation of the optical isolator element 10 can be further enhanced. Further, the protective material 25 may be disposed so as to be in contact with the outer peripheral surface of the Faraday rotator 12 having the highest thermal conductivity in the optical isolator element 10, but the outer periphery of the polarizer 11a and the polarizer 11b is also the same. If it covers, the heat dissipation of the optical isolator element 10 can further be improved. Further, the protective material 25 is preferably arranged so as to contact the holding member 32 as well.

  As a method for producing the protective material 25, for example, a resin before curing is injected into a syringe, and between the outer peripheral surface of the optical isolator element 10 and the inner peripheral surface of the magnet 21 is filled with the syringe, the resin is thermally cured. Can be produced. The resin constituting the protective material 25 is filled in a narrow gap between the inner peripheral surface of the magnet 21 and the outer peripheral surface of the optical isolator element 10, so that the viscosity before curing can be dispensed with a small diameter injection needle. Thus, it is preferably 100 Pa · s or less. The resin as the precursor of the protective material 25 is filled until at least the Faraday rotator 12 is covered. Moreover, you may fill resin between the outer peripheral surface of polarizer 11a, 11b and the magnet 21 as needed.

  Thereafter, the protective material 25 is formed by heating and curing the resin by a heating means such as a heater or a thermostatic bath. In addition, as the resin, the optical isolator element 10, the adhesive used for bonding the optical isolator element 10 and the holding member 32, and the optical fiber 31 and the coating 31a are less than 120 ° C., which is less affected by heating and mechanical stress. A silicone resin that cures and becomes a rubber elastic body or gel after curing is desirable.

  In the optical isolator module of the present invention, since the optical isolator element can be fixed with resin that covers the outer periphery of the Faraday rotator instead of solder or low-melting glass, the polarizer of the optical isolator element and the Faraday rotator It is possible to reduce deterioration due to heat of the adhesive between them.

  In addition, the protective material 25 should just be thermally connected with the optical isolator 10 or the magnet 21, and does not necessarily need to be mechanically joined with an adhesive agent. For example, the optical isolator 10 may be inserted into a resin previously molded into a predetermined shape such as a cylindrical shape, and this may be inserted inside the magnet 21.

  FIG. 2 is a schematic view showing the optical isolator section 20 of the optical isolator module 40 of the present invention in a perspective view. Light emitted from a light source such as a semiconductor laser passes on the optical axis and reaches the optical isolator element 10, but is generally unstable for several tens of seconds after the light source is turned on until the operation of the LD is stabilized. The output light may oscillate. Recently, as a method of eliminating the temporarily unstable output light, by making the polarization direction of the polarizer 11a on the light incident side of the optical isolator element 10 orthogonal to the polarization direction of the light source as shown in the figure, There is one that uses a means in which light is absorbed by the polarizer 11a on the incident side and the input of the semiconductor laser light to the optical fiber 31 is temporarily interrupted. At this time, the blocked light is converted into thermal energy, and heat is easily generated in the optical isolator element 10. In the optical isolator module 10 of the present invention, the generated heat is propagated from the Faraday rotator 12 to the protective material 25, radiated from the protective material 25 to the outside, and also radiated from the magnet 21.

Here, the thermal resistance R of the protective material 25 is
R = t / (λ · A)
(T is the distance between the outer periphery of the optical isolator element and the inner wall of the magnet, λ is the thermal conductivity, and A is the surface area). In order to efficiently dissipate heat generated by the polarizer 11a to the outside, it is necessary to make the thermal resistance of the protective material 25 smaller than the thermal resistance of the polarizer 11a. Therefore, when heat is radiated from the protective material 25 via the Faraday rotator 12, the thermal conductivity of the protective material 25 needs to be selected to be larger than the thermal conductivity of the polarizer 11a.

  Since the thermal conductivity of the polarizer 11a is 0.94 to 1.05 W / m · K as described above, the thermal conductivity of the protective material 25 is more than twice the thermal conductivity of the polarizer 11a. It is desirable that it is 2.0 W / m · K or more.

  Next, FIG. 3 is a longitudinal sectional view showing an example of another embodiment of the optical isolator module 50 of the present invention. In FIG. 3, the optical isolator module 50 includes an optical isolator element 10, an optical fiber fixing part 30, and a protective material 25 that connects the optical isolator element 10 and the optical fiber fixing part 30. The optical fiber fixing portion 30 includes a holding member 32 and a first holder 33 in which the holding member 32 is fitted, and the optical fiber 31 is passed through through holes 33b and 32b penetrating inside thereof.

  A protective material 25 is attached from the outer peripheral side surface of the optical isolator element 10 to the end surface 32 a of the holding member 32 and the end surface of the first holder 33. Thereby, the heat generated in the optical isolator element 10 is radiated to the holding member 32 and the first holder 33 via the protective material 25. As shown in FIG. 3, the protective material 25 is provided so as to form a convex curved surface toward the outside in order to secure a cross-sectional area of the heat flow path from the optical isolator element 10 to the first holder 33. Is preferred. The heat is also radiated to the holding member 32 through the polarizer 11 b bonded to the holding member 32. Furthermore, since the surface 10a of the polarizer 11a and the surface of the protective material 25 are structured to be exposed to the outside air, heat is also radiated from these surfaces.

  In the embodiment of FIG. 3, magnetic garnet is used for the Faraday rotator 12 of the optical isolator element 10. Therefore, in the embodiment of FIG. 3, the magnet 21 in the embodiment of FIG. 1 can be omitted. Other configurations are the same as those of the embodiment in FIG.

  Next, a third embodiment of the optical isolator module of the present invention will be described with reference to FIG. FIG. 4 is a longitudinal sectional view showing an optical isolator module 60 according to the third embodiment of the present invention.

  The optical isolator module 60 is different from the optical isolator module 40 in that the number of polarizers and Faraday rotators is increased. Specifically, in the optical isolator module 60, the optical isolator element 10A includes three polarizers 11a, 11b, and 11c and two Faraday rotators 12a and 12b, which are alternately arranged. . The light transmission polarization direction of the polarizer 11a on the light incident side and the light transmission polarization direction of the polarizer 11b sandwiched between them are shifted by 45 °, and the light output side polarizer 11c is further shifted by 45 °. Thus, the incident polarization direction is rotated by 90 ° and emitted. The isolation characteristic of such an optical isolator element 10A is approximately 1.5 times better than that of a type consisting of three optical elements such as the optical isolator element 10, and particularly a long-distance semiconductor laser module or the like. Is suitable for use in.

  FIG. 5 is a longitudinal sectional view showing an embodiment of the optical element module 70 of the present invention. An optical element module 70 according to an embodiment of the present invention includes an optical unit 65 that includes a light emitting element 61 such as an LD, a lens 62, a stem 63, and an electronic cooling element 64, a case 71 that houses the optical unit 65, and an optical isolator. A module 40 and a second holder 72 for holding the optical isolator module 40 are provided. Note that the monitor PD (photodiode), wiring lead wires, and the like built in the case 71 are omitted.

  The optical unit 65 mounts and fixes the light emitting element 61 on the stem 63 by soldering, mounts a lens 62 that collects the light emitted from the light emitting element 61 on the stem 63 by soldering or YAG laser, and the stem 63 is an electronic cooling element. It is formed by mounting and fixing on 64 with solder. The optical unit 60 is accommodated in a case 71 and fixed with solder or the like. Further, the optical isolator module 40 is inserted into the second holder 72, and the flange portion 72a of the second holder 72 is brought into contact with the pipe member 71a made of stainless steel or Fe—Ni material provided in the case 71. . Finally, after adjusting the optical isolator module 40 in the XYZ directions with respect to the optical axis of the light emitted from the optical unit 65, the flange portion 72a of the second holder 72 is replaced with the pipe member 71a, and the optical isolator module 40 The optical element module 70 is completed by welding one holder 33 to the second holder 72 with a YAG laser. As described above, since the optical element module 70 includes the optical isolator module 40 of the present invention, heat generated in the optical isolator element 10 can be efficiently radiated and cost increase can be suppressed.

  In the present embodiment, examples of the optical isolator modules 40, 50, 60 and the optical element module 70 having the optical fiber 31 are shown. However, the present invention is not limited to such a form, and for example, the optical fiber 31. Instead of this, a configuration in which the through hole 32a of the holding member 32 is filled with a translucent member, or a form in which light is simply transmitted through the through hole may be employed. Further, the optical fiber fixing part 30 may be an optical receptacle.

  Hereinafter, an optical isolator module 40 shown in FIG. 1 was produced as an example of the present invention.

  In FIG. 1, a holding member 32 made of zirconia ceramics having a through hole 32a at the center is press-fitted and fixed to a counterbore portion 33a of a first holder 33 made of stainless steel. Next, the optical fiber 31 is inserted into the second through hole 33b of the first holder 33, and the tip of the optical fiber 31 from which the coating 31a has been removed is fixed in the through hole 32b of the holding member 32 with an adhesive, The covering portion 31a of the optical fiber 31 was fixed to the second through hole 33b of the first holder 33 with an adhesive. The front end surface 32a of the holding member 32 was set to be inclined by 4 ° with respect to the surface orthogonal to the through hole 32b. Thereby, the optical fiber fixing | fixed part 30 was produced.

Next, after rotating and aligning the angles of the transmission polarization planes of the two polarizers 11a and 11b to be 45 °, a Faraday rotator is used with a translucent adhesive between the polarizers 11a and 11b. 12 were stuck together and fixed. The light incident / exit surfaces of the polarizers 11a and 11b have a size of about 0.4 mm in length × about 0.4 mm in width = about 0.16 mm ² . Further, the angle in the optical axis direction for forming the bottom surface 10 a of the optical isolator element 10 was cut to 4 °, which is the same as the angle of the front end surface 32 a of the holding member 32. Each of the two polarizers 11a and 11b and the Faraday rotator 12 has a thickness of about 0.5 mm.
The light exit surface of the polarizer 11b of the optical isolator element 10 was fixed to the front end surface 32a of the holding member 32 with a translucent epoxy adhesive having a refractive index of about 1.5 which is substantially the same as that of the optical fiber 31.

  Next, a cylindrical magnet 21 having an outer diameter φ1.8 mm, an inner diameter φ1.05 mm, and a length 2.15 mm was inserted and fixed to the outer peripheral portion of the holding member 32 so as to cover the optical isolator element 10. After the gap between the outer peripheral surface of the Faraday rotator 12 and the polarizer 11b of the optical isolator element 10 and the inner peripheral surface of the magnet 21 is filled with a silicone resin containing aluminum oxide having a viscosity of about 60 Pa · s, 120 The optical isolator module 40 was produced by heating and curing (gelling) at 0 ° C. In addition, the silicone resin used as the protective material 25 was filled up to about 1 to 1.3 mm in a position that specifically protects the side surfaces of the light emitting side polarizer 11b and the Faraday rotator 12, specifically in the depth direction.

  In the optical isolator module according to the embodiment of the present invention and the optical isolator module without the protective material 25, the light incident is performed for 1 minute so that the light spot size is φ150 μm and the light absorption power of the polarizer 11a is 100 mW. The amount of decrease was compared.

  According to this result, in the optical isolator module without the protective material 25, the bonding portion between the polarizer 11a of the optical isolator element 10 and the Faraday rotator 12 is in an overheated state of 250 ° C. or higher. The output was reduced by 0.5 dB. On the other hand, in the optical isolator module according to the embodiment of the present invention, the junction between the polarizer 11a and the Faraday rotator 12 of the optical isolator element 10 is about 70 ° C., which suppresses heat generation as compared with the comparative example described above. Therefore, a decrease in output of the optical fiber can be reduced, and good results can be obtained. Further, in the optical isolator module according to the embodiment of the present invention, since the protective material 25 is a gel-like material, the output deterioration of the optical fiber is small before and after the temperature cycle (−40 to 85 ° C., 500 cycles) is input, and mechanical. It was also confirmed that the effect of stress was small.

1 is a longitudinal sectional view showing an optical isolator module according to a first embodiment of the present invention. It is a schematic diagram which shows the mode of the light which injects into an optical isolator element. It is a longitudinal cross-sectional view which shows the optical isolator module which concerns on the 2nd Embodiment of this invention. It is a longitudinal cross-sectional view which shows the optical isolator module which concerns on the 3rd Embodiment of this invention. It is a longitudinal cross-sectional view which shows one Embodiment of the optical element module of this invention. It is a longitudinal cross-sectional view which shows the conventional optical isolator module.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 10 '... Optical isolator element 10a ... Bottom face of optical isolator element 11a, 11b, 11c ... Polarizer 12, 12' ... Faraday rotator 20 ... Optical isolator part 21 ... Magnet 25 ... Protective material 30 ... Optical fiber terminal 31 ... Optical fiber 31a ... Belly part of optical fiber 32 ... Cylindrical body (holding member)
32a ... End surface of cylindrical body 32b ... Through hole 33 ... First holder 33a ... Counterbore 33b ... Second through hole 40, 50 ... Optical isolator module 60 ... Optical unit 61 ... Light emitting element 62 ... Lens 63 ... Stem 64 ... Electronic cooling element 70 ... Optical element module 71 ... Case 71a ... Case pipe 72 ... Second holder 72a ... Flange of holding member

Claims (6)

A flat Faraday rotator, and a first polarizer and a second polarizer each having a light incident / exit surface bonded to each main surface of the Faraday rotator through which light is incident or emitted via an adhesive, An optical isolator element having
A cylindrical holding member in which the second polarizer is bonded to one end surface so as to block a through hole through which light is transmitted;
In a state in contact with the outer periphery of the Faraday rotator, the protective material covering the Faraday rotator, and
The optical isolator module, wherein the protective material contains a resin and has a higher thermal conductivity than the first polarizer. The optical isolator module according to claim 1, wherein the protective material is made of a silicone resin containing metal powder. The optical isolator module according to claim 1, wherein the protective material is disposed between an outer peripheral surface of the Faraday rotator and the holding member. The said protective material covers the said 1st polarizer and the said 2nd polarizer in the state which contacted the outer periphery of the said 1st polarizer and the said 2nd polarizer, The any one of Claims 1-3 characterized by the above-mentioned. The optical isolator module described in 1. Further comprising a cylindrical magnet arranged to enclose the optical isolator element in the hole,
The optical isolator module according to claim 1, wherein the protective material is disposed in contact with an inner peripheral surface of the magnet. The optical isolator module according to any one of claims 1 to 5,
A cylindrical first holder in which one end of the holding member is inserted and fixed;
A second holder into which the first holder is inserted;
A light emitting element that transmits light toward the through hole of the holding member via the optical isolator element;
An optical element module comprising a case that houses the light emitting element and is joined to the second holder.