Optical Module

Abstract

To provide an improved novel optical module to be configured to suppress heat transmission to a device, adversely affecting characteristics of light transmitted within a housing when receiving heat from, for example a heat generating part.SOLUTION: An optical module includes a housing in which light is transmitted, for example inside the housing, a heat generating part, a device that is provided inside the housing and that changes characteristics of the light transmitted in the housing when receiving heat, and a first member that is thermally connected to the heat generating portion and the device. For the first member, a cavity is provided in a heat transfer passage from the heat generating part to the device in a state of suppressing convection heat transfer into the housing. The housing may be hermetically sealed. The first member may have a cavity opened outside the housing or a cavity which is a closed space as the cavity.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an optical module. [Background technology]

[0002] Conventionally, optical modules that include optical devices, optical components, a temperature control device, and the like and transmit light within a housing have been known (see, for example, Patent Document 1). The optical devices include, for example, photodiodes and modulators. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-178117 Summary of the Invention [Problem to be solved by the invention]

[0004] This type of optical module may have a heat-generating part, such as a modulator driver or a chip-on-submount, inside the housing. In such cases, if the optical device or temperature control device receives heat generated by the heat-generating part, the characteristics of the light transmitted inside the housing may change, which may ultimately change the optical characteristics of the optical module. Therefore, blocking heat from the heat-generating part to the optical device or temperature control device is an important issue.

[0005] Therefore, one of the objects of the present invention is to provide an optical module with an improved new configuration that makes it possible to suppress the transfer of heat from a heat-generating portion to a device that, when heated, would affect the characteristics of the light transmitted within the housing. [Means for solving the problem]

[0006] The optical module of the present invention comprises, for example, a housing through which light is transmitted, a heat generating portion, a device provided within the housing that changes the characteristics of the light transmitted within the housing when it receives heat, and a first member thermally connected to the heat generating portion and the device, wherein a cavity is provided in the first member in the heat transfer path from the heat generating portion to the device in a state in which convective heat transfer into the housing is suppressed.

[0007] In the optical module, the housing may be hermetically sealed.

[0008] In the optical module, the first member may be provided with a cavity that is open to the outside of the housing as the cavity.

[0009] In the optical module, the first member may be provided with a cavity that is a closed space as the cavity.

[0010] In the optical module, the first member may have a cavity with an opening into the housing as the cavity, and the optical module may include a covering member that at least partially covers the opening.

[0011] In the optical module, the covering member may be at least one of a second member bonded to the first member and an adhesive that bonds the first member and the second member.

[0012] In the optical module, the first member may be provided with a cavity that is at least partially located within the housing as the cavity.

[0013] In the optical module, the first member may be provided with a cavity positioned outside the housing as the cavity.

[0014] In the optical module, the heat generating portion and the device may be arranged at a distance from each other in a first direction, and the first member may be provided with a plurality of cavities at a distance from each other in the first direction as the cavity.

[0015] In the optical module, the heat generating portion and the device may be arranged at intervals in a first direction, and the first member may be provided with a plurality of cavities as the cavity, the cavities being spaced apart in a second direction intersecting the first direction.

[0016] In the optical module, the first member may be provided with a cavity having an inner surface provided with a heat transfer layer having a higher thermal conductivity than the first member.

[0017] The optical module may include a plurality of devices as the device, and the first member may be provided with a cavity as the cavity, the cavity being positioned on a heat transfer path between the plurality of devices.

[0018] The optical module may include, as the heat generating portion, a heat generating portion located within the housing.

[0019] The optical module may include, as the heat generating portion, a heat generating portion positioned outside the housing.

[0020] The optical module may include an electrically operated heat generating portion as the heat generating portion.

[0021] In the optical module, the heat generating portion may be flip-chip mounted on the first member.

[0022] The optical module may include a joint portion where a plurality of members are joined together and which is heated during joining.

[0023] In the optical module, the joint may be located outside the housing, and the first member may be provided with a cavity that is a closed space located outside the housing.

[0024] In the optical module, the housing may be the first member.

[0025] The optical module may include, as the first member, a support member that supports the device.

[0026] The optical module may include, as the first member, a fixing member fixed to the support member.

[0027] The optical module may include a first member made of a porous material as the first member. [Effects of the Invention]

[0028] According to the present invention, for example, an optical module having an improved and novel configuration can be obtained. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 1 is an exemplary schematic side view (partial cross-sectional view) showing the internal configuration of the optical module according to the first embodiment. [Figure 2] FIG. 2 is an exemplary schematic plan view of the rear surface of the optical module according to the first embodiment. [Figure 3] FIG. 3 is an exemplary schematic cross-sectional view of a part of the optical module according to the second embodiment. [Figure 4] FIG. 4 is an exemplary schematic side view (partial cross-sectional view) showing the internal configuration of the optical module according to the third embodiment. [Figure 5] FIG. 5 is an exemplary schematic side view (partial cross-sectional view) showing the internal configuration of the optical module according to the fourth embodiment. [Figure 6] FIG. 6 is an exemplary schematic side view (partial cross-sectional view) showing the internal configuration of the optical module according to the fifth embodiment. [Figure 7] FIG. 7 is an exemplary schematic side view (partial cross-sectional view) showing the internal configuration of the optical module according to the sixth embodiment. [Figure 8] FIG. 8 is an exemplary schematic cross-sectional view of a part of the optical module according to the sixth embodiment. [Figure 9] FIG. 9 is an exemplary schematic side view (partial cross-sectional view) showing the internal configuration of the optical module according to the seventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0030] Exemplary embodiments of the present invention are disclosed below. The configurations of the embodiments described below, as well as the actions and results (effects) brought about by the configurations, are merely examples. The present invention can also be realized by configurations other than those disclosed in the following embodiments. Furthermore, according to the present invention, it is possible to obtain at least one of the various effects (including derivative effects) obtained by the configurations.

[0031] The following embodiments have similar configurations. Therefore, the configurations of the respective embodiments provide similar actions and effects based on the similar configurations. In the following, the similar configurations are given the same reference numerals, and redundant explanations may be omitted.

[0032] In this specification, ordinal numbers are given for convenience to distinguish between members, parts, directions, etc., and do not indicate priority or order.

[0033] In each drawing, the X direction is represented by an arrow X, the Y direction is represented by an arrow Y, and the Z direction is represented by an arrow Z. The X direction, Y direction, and Z direction intersect with each other and are perpendicular to each other.

[0034] [First embodiment] Fig. 1 is a side view showing the internal configuration of the optical module 100A (100) of the first embodiment. Fig. 2 is a plan view showing the back surface of the bottom wall 10a of the housing 10 of the optical module 100A. The optical module 100 has a configuration similar to that of the optical module disclosed in, for example, PCT / JP2021 / 002326 (WO-A1-2021 / 153462).

[0035] As shown in FIG. 1, the optical module 100A includes a housing 10, a feedthrough 21, a support base 22, and an interposing member .

[0036] The housing 10 has a bottom wall 10a, a peripheral wall 10b, and a top wall 10c. The bottom wall 10a has a generally rectangular and plate-like shape. The bottom wall 10a intersects with the Z direction and extends generally perpendicular to it, extending in the X and Y directions. The peripheral wall 10b extends from the edge of the bottom wall 10a with a generally constant thickness generally along the Z direction. The peripheral wall 10b may also be referred to as a side wall. The top wall 10c has a generally rectangular and plate-like shape. The top wall 10c intersects with the Z direction and extends generally perpendicular to it, extending in the X and Y directions.

[0037] The peripheral wall 10b is provided with a window member 10d that transmits light between the inside and outside of the housing 10 (accommodation chamber S). Within the housing 10, light that is emitted from inside the housing 10 to the outside of the housing 10, light that is incident from the outside of the housing 10 into the housing 10, light that passes through devices and components within the housing 10, etc. are transmitted.

[0038] The bottom wall 10a may be made of a material with high thermal conductivity, such as copper tungsten (CuW), copper molybdenum (CuMo), aluminum oxide (Al2O3), etc. The peripheral wall 10b and the top wall 10c may be made of a material with a low thermal expansion coefficient, such as an Fe-Ni-Co alloy, aluminum oxide (Al2O3), etc.

[0039] The peripheral edge of the top wall 10c, also referred to as a lid, overlaps with the Z-direction edge of the peripheral wall 10b in the Z direction. By joining the peripheral edge of the top wall 10c and the Z-direction edge of the peripheral wall 10b, an accommodation chamber S for accommodating components and devices is formed within the housing 10. A gas such as an inert gas or air is accommodated within the accommodation chamber S (inside the housing 10). The accommodation chamber S may be hermetically sealed.

[0040] The feedthrough 21 has a conductor 21a and an insulating portion, and penetrates a portion of the peripheral wall 10b of the housing 10. The conductor 21a of the feedthrough 21 may be made of a highly conductive metal material such as a copper-based metal. The insulating portion of the feedthrough 21 may be made of an insulator such as ceramic. The boundary between the feedthrough 21 and the housing 10 is, for example, insulated and hermetically sealed.

[0041] The feedthrough 21 also supports components such as a modulator driver 31 and a transimpedance amplifier 32 (see FIG. 2).

[0042] 1, the support base 22 is fixed on the bottom wall 10a of the housing 10, and extends at a substantially constant height in the Z direction, intersecting the Z direction and substantially perpendicular to the Z direction. The support base 22 supports an optical component such as a lens 51. The lens 51 is adhered and fixed to the support base 22 with an adhesive 52. The support base 22 may be configured as a multilayer wiring board.

[0043] The interposing member 23 is interposed between a TEC (thermoelectric cooler) 41 and the modulator 33, coherent mixer 34 (see FIG. 2), photodiodes serving as light receivers, and the like. The TEC 41 has a Peltier element, and electrically adjusts the temperatures of the modulator 33, coherent mixer 34, photodiodes, and the like by operating the Peltier element, and may also be referred to as a temperature control mechanism. The interposing member 23 has a plate-like shape and may be made of a material with high thermal conductivity. The modulator 33 is electrically connected to the modulator driver 31 via bonding wires 36.

[0044] Furthermore, a TEC 42 separate from the TEC 41 is provided on the bottom wall 10a, and a chip-on submount 35 (light-emitting unit) is provided on the opposite side of the TEC 42 from the bottom wall 10a. The TEC 42 has a different object of temperature adjustment, but has a configuration substantially similar to that of the TEC 41. The chip-on submount 35 also has a submount and a light-emitting element such as a semiconductor laser element mounted on the submount.

[0045] Components such as a modulator driver 31, a transimpedance amplifier 32, a modulator 33, a coherent mixer 34, a chip-on submount 35, TECs 41 and 42, and a lens 51 are housed in a housing 10. In addition to these components, the housing 10 may also house optical components (not shown) such as a mirror, a beam combiner, a beam splitter, and an optical isolator.

[0046] Among the components housed in the housing 10, the modulator 33, coherent mixer 34, chip-on submount 35, TECs 41 and 42, etc. are devices (hereinafter referred to as first devices) that may change the characteristics (e.g., wavelength) of light transmitted within the housing 10 when they receive heat. Examples of such first devices include a heater, a wavelength locker as a wavelength detector, a vertical-cavity surface-emitting laser (VCSEL), and an modulator-integrated semiconductor laser (EML).

[0047] The modulator driver 31, the transimpedance amplifier 32, the chip-on submount 35, etc. generate heat when electrically operated. The modulator driver 31, the transimpedance amplifier 32, and the chip-on submount 35 are examples of heat-generating parts located inside the housing 10.

[0048] In the optical module 100 configured as described above, if heat generated in the heat-generating portion is transferred to the first device, the characteristics of the light transmitted within the housing 10 may change, which may ultimately result in changes in the optical characteristics of the optical module 100. Therefore, in this embodiment, cavities 61 and 62 are provided in components (hereinafter referred to as first components) that are thermally connected to the heat-generating portion and the first device and form a heat transfer path (hereinafter referred to as a heat transfer path), such as the housing 10, the feedthrough 21, and the support base 22. The cavities 61 and 62 are provided in the first components so as to be interposed in the heat transfer path from the heat-generating portion to the first device, and therefore can block heat transfer in the heat transfer path. In this embodiment, the cavities 61 and 62 are at least partially located within the housing 10 (within the housing chamber S). The cavity 61 may be formed during the manufacturing of the component in which the cavity 61 is provided, or may be formed after the optical module 100 is assembled. The cavity 62 is formed during the manufacturing of the member in which the cavity 62 is provided. Among the first members, a member that supports a first device such as the feedthrough 21 is an example of a support member, and a member fixed to the support member such as the housing 10 is an example of a fixed member.

[0049] As shown in FIG. 1 , a cavity 61 is provided in the feedthrough 21 and the bottom wall 10a. The cavity 61 has a predetermined width in the X direction and extends in the Y and Z directions, forming a slit shape. The cavity 61 is provided across the feedthrough 21 and the bottom wall 10a, penetrates the bottom wall 10a, and opens to the rear surface 10a1 of the bottom wall 10a. In other words, the cavity 61 may also be referred to as a blind hole. The cavity 61 can suppress heat transfer from the modulator driver 31 or transimpedance amplifier 32, which are heat-generating elements, to the modulator 33, coherent mixer 34, TEC 41, etc. via the feedthrough 21 and the bottom wall 10a.

[0050] Here, if the cavity 61 were open to the accommodating chamber S, the gas in the cavity 61 would be heated by heat transfer at the feedthrough 21 or the bottom wall 10a, and the heat would move into the accommodating chamber S by convective heat transfer of the gas, warming the first device in the accommodating chamber S. As a result, there is a risk that the heat-shielding effect of the cavity 61 would be weakened. Therefore, in this embodiment, the cavity 61 is provided in a state that is not in communication with the accommodating chamber S, that is, in a state that convective heat transfer from the cavity 61 to the accommodating chamber S (inside the housing 10) is suppressed.

[0051] Furthermore, cavity 61 is open at rear surface 10a1 of bottom wall 10a. In other words, cavity 61 is open to the outside of housing 10. This allows heat to flow out of housing 10 from the opening on rear surface 10a1 side by convection heat transfer of gas heated in cavity 61. This prevents heat from remaining inside cavity 61 and thus inside housing 10, thereby enhancing the effect of cavity 61 in suppressing heat transfer.

[0052] 2, in the feedthrough 21, a plurality of cavities 61 are arranged in series at intervals in the X direction and in parallel at intervals in the Y direction. A wiring path may be provided within the feedthrough 21, but if one large cavity 61 were provided, it may be difficult to route the wiring path. In this regard, in the present embodiment, the plurality of cavities 61 suppress heat transfer, while the wiring path is passed through a portion between the plurality of cavities 61 (hereinafter referred to as a first portion P1), making it possible to relatively easily ensure the wiring path.

[0053] Furthermore, in the feedthrough 21, another cavity 61 is disposed offset in the X direction with respect to a portion between two adjacent cavities 61 spaced apart in the Y direction. In other words, the multiple cavities 61 are disposed in a staggered arrangement. Because the first portions P1 serve as heat transfer paths, if multiple first portions P1 were arranged in the X direction, the heat transfer paths would be shortened, facilitating heat transfer. In this regard, in the present embodiment, the multiple cavities 61 and the first portions P1 are disposed in a staggered arrangement, which makes it possible to lengthen the heat transfer paths via the first portions P1 and further suppress heat transfer via the feedthrough 21 and the bottom wall 10a.

[0054] As shown in FIG. 1 , a cavity 61 is also provided in the support base 22 and the bottom wall 10a. The cavity 61 extends between the support base 22 and the bottom wall 10a, penetrates the bottom wall 10a, and opens to the rear surface 10a1 of the bottom wall 10a. That is, the cavity 61 may also be referred to as a blind hole. The cavity 61 can suppress heat transfer from the chip-on submount 35, which is a heat-generating part, to the modulator 33, the coherent mixer 34, the TEC 41, and the like via the support base 22 and the bottom wall 10a. The cavity 61 is also located in the heat transfer path between the TECs 41 and 42. Therefore, the cavity 61 can suppress heat transfer between the TECs 41 and 42 via the support base 22 and the bottom wall 10a. The TECs 41 and 42 each have a cooling part and a heat-generating part. Therefore, the cavity 61 can prevent heat from being transferred from the heat-generating parts of the TECs 41 and 42 to the modulator 33, coherent mixer 34, chip-on submount 35, etc. via the support base 22 and bottom wall 10a.

[0055] Furthermore, although the support base 22 has an opening 61a leading to the storage chamber S of the cavity 61, i.e., to the housing 10, the opening 61a is covered and blocked by at least one of the lens 51 and the adhesive 52. This prevents the heat-shielding effect of the cavity 61 from being weakened by convective heat transfer from the cavity 61 to the storage chamber S (inside the housing 10). In this case, the cavity 61 can be formed as a through-hole, which may make it easier to form the cavity 61 than when the cavity 61 is formed as a hole with a bottom that extends partway through. The lens 51 and the adhesive 52 are examples of a covering member. The lens 51 is also an example of an optical component or part attached to the first member.

[0056] Furthermore, the support base 22 is also provided with a cavity 62 that is closed within the support base 22. In other words, the cavity 62 is a closed space. The cavity 62 has a predetermined width in the X direction and extends in the Y and Z directions, and is provided in the form of a slit. This cavity 62 is also provided in a state that is not in communication with the accommodation chamber S, that is, in a state that convective heat transfer from the cavity 62 to the accommodation chamber S (inside the housing 10) is suppressed. Therefore, the cavity 62 also provides the same actions and effects as the cavity 61.

[0057] As described above, in this embodiment, the cavities 61 and 62 are provided in the heat transfer path of the first member thermally connected to the heat generating portion and the first device. Therefore, according to this embodiment, the cavities 61 and 62 can suppress heat transfer from the heat generating portion to the first device, and therefore it is possible to suppress changes in the characteristics of light transmitted within the housing 10 due to heat generation by the heat generating portion, and ultimately changes in the optical characteristics of the optical module 100.

[0058] It should be noted that the cavities 61, 62 and the storage chamber S do not need to be completely isolated from each other, and the cavities 61, 62 may be in communication with the storage chamber S as long as the optical characteristics are not substantially affected by a temperature rise in the first device due to convective heat transfer from the cavities 61, 62. In other words, the lens 51 (component, optical component) or the adhesive 52 may partially close the opening 61 a of the cavity 61 within this range.

[0059] [Second embodiment] 3 is a cross-sectional view of the peripheral portion of a cavity 61 provided in an optical module 100B (100) according to the second embodiment. In this embodiment, as in the first embodiment, the cavity 61 is provided across the feedthrough 21 and the bottom wall 10a. In this embodiment, the same effects as those in the first embodiment can be obtained based on the same configuration.

[0060] However, in this embodiment, a heat transfer layer 61b having a higher thermal conductivity than the feedthrough 21 is provided on the inner surface of the cavity 61. The heat transfer layer 61b also extends to an opening 61c of the cavity 61 provided on the back surface 10a1 of the bottom wall 10a of the housing 10. This configuration can improve heat dissipation from the peripheral portion of the cavity 61 to the outside of the housing 10, thereby further suppressing heat transfer from the heat-generating portion to the first device.

[0061] [Third embodiment] 4 is a side view showing the internal configuration of an optical module 100C (100) according to the third embodiment. As in the first embodiment, in this embodiment, cavities 61 and 62 are provided in the feedthrough 21, the support base 22, and the bottom wall 10a. In this embodiment, the same effects as in the first embodiment can be obtained based on the same configuration.

[0062] However, in this embodiment, some of the cavities 61 (61C1, 61C2) are bent or have branches. This configuration has advantages such as increasing heat dissipation from the cavities 61 by arranging the cavities 61 in locations where temperatures are likely to be higher, and increasing the degree of freedom in wiring paths. Note that the cavities 62 may also be bent or have branches.

[0063] In this embodiment, the conductor 21a of the feedthrough 21 and the conductor of the external wiring 71 are mechanically and electrically joined via a joint 72. The joint 72 is a joint that is heated to melt during joining and cooled to solidify, such as a soldered or welded joint, and is electrically conductive.

[0064] The feedthrough 21 has a cavity 62C as a closed space at a position outside the housing 10. This cavity 62C can suppress heat transfer from the heated joint 72 to components inside the accommodation chamber S (inside the housing 10), such as the modulator driver 31, via the feedthrough 21 when the joint 72 is joined. Here, it is preferable that the cavity 62C is provided as a closed space and is not open to the outside of the feedthrough 21. This is because if the cavity 62C were open to the outside of the feedthrough 21, heat dissipation from the surrounding area of ​​the cavity 62C would increase, and there is a risk that sufficient heat will not be provided to melt the joint 72 when it is joined.

[0065] [Fourth embodiment] 5 is a side view showing the internal configuration of an optical module 100D (100) according to the fourth embodiment. The optical module 100D of this embodiment has a similar configuration to the optical module 100C of the third embodiment, except that the conductor 21a of the feedthrough 21 penetrates the feedthrough 21 in the Z direction. This embodiment also provides the same effects as the third embodiment, based on the same configuration.

[0066] [Fifth embodiment] 6 is a side view showing the internal configuration of the optical module 100E (100) of the fifth embodiment. In this embodiment, the same effects as those in the first embodiment can be obtained based on the same configuration.

[0067] However, in the optical module 100E of this embodiment, a feedthrough 21E is provided instead of the bottom wall of the housing 10. In other words, the feedthrough 21E functions as the bottom wall of the housing 10. The feedthrough 21E is configured as a multilayer wiring board.

[0068] First devices such as a modulator driver 31, a transimpedance amplifier 32, a modulator 33, a coherent mixer 34, and a chip-on submount 35 are flip-chip mounted to the feedthrough 21E and supported by the feedthrough 21. An optical component such as a lens 51 is fixed to the feedthrough 21E via an adhesive 52. The feedthrough 21E is an example of a first member and also an example of a support member.

[0069] The feedthrough 21E is provided with a conductor 21b that electrically connects a plurality of electrical components.

[0070] The modulator driver 31, the transimpedance amplifier 32, the first device, and the top wall 10c of the housing 10 are thermally connected via a heat transfer member such as a relatively hard heat conduction block 91 or a relatively soft heat conduction sheet 92. The heat transfer member may be formed of the heat conduction block 91 or the heat conduction sheet 92 alone, or may be formed of a combination of the heat conduction block 91 and the heat conduction sheet 92. Furthermore, heat dissipation members such as heat sinks 93 and 94 are fixed to the top wall 10c in a state exposed to the outside of the housing 10. This configuration suppresses a rise in temperature of the first device.

[0071] The insulating portion (general portion) of feedthrough 21E may be made of a porous material such as machinable ceramics, which can reduce the heat transfer coefficient of feedthrough 21E itself and suppress heat transfer in the heat transfer path of feedthrough 21E.

[0072] Furthermore, feedthrough 21E (optical module 100E) is electrically and mechanically connected and fixed to the conductor of mounting substrate 81 via joints 82 such as solder balls. Mounting substrate 81 is an example of a fixing member. Furthermore, mounting substrate 81 is thermally connected to feedthrough 21E, and is thermally connected to the heat-generating portion and the first device via feedthrough 21E. Therefore, mounting substrate 81 is both an example of a first member and an example of a fixing member.

[0073] In the present embodiment, a cavity 61 is provided in each of the heat transfer paths of the feedthrough 21E and the mounting substrate 81, which serve as first members thermally connected to the heat generating portion and the first device. Therefore, according to the present embodiment, the cavity 61 can suppress heat transfer from the heat generating portion to the first device, thereby suppressing changes in the characteristics of light transmitted within the housing 10 due to heat generation by the heat generating portion and, ultimately, changes in the optical characteristics of the optical module 100E.

[0074] [Sixth embodiment] 7 is a side view showing the internal configuration of an optical module 100F (100) according to a sixth embodiment. The optical module 100F according to this embodiment has a similar configuration to the optical module 100E according to the fifth embodiment, except that it includes a cover conductor 21c that covers the conductor 21b with a gap therebetween. This embodiment also provides the same effects as the fifth embodiment.

[0075] Furthermore, the feedthrough 21E is provided with a cavity 62 as a closed space instead of the cavity 61. The cavity 62 can also be provided in the mounting substrate 81.

[0076] 8 is a cross-sectional view of a portion where conductor 21b and cover conductor 21c are provided, taken along the X-axis. As shown in FIG. 8, cover conductor 21c is a bent plate-like member that extends in the X-axis direction with a substantially U-shaped cross section. Cover conductor 21c is provided on the opposite side of conductor 21b, through which a signal is transmitted, from feedthrough 21E, so as to partially cover conductor 21b, and is electrically connected to a ground conductor (not shown). This configuration allows impedance matching in conductor 21b, thereby reducing transmission loss of signals passing through conductor 21b. Cover conductor 21c is not limited to a plate-like member and may be a wire, mesh, or the like.

[0077] [Seventh embodiment] 9 is a side view showing the internal configuration of an optical module 100G (100) according to the seventh embodiment. The optical module 100G according to this embodiment has a configuration similar to that of the optical module 100F according to the sixth embodiment, except that the modulator driver 31 and the transimpedance amplifier 32 are provided outside the housing 10. This embodiment also provides the same effects as those of the sixth embodiment.

[0078] In the present embodiment, the modulator driver 31 and the transimpedance amplifier 32 serving as the heat generating unit are located outside the housing 10. With this configuration, compared to a configuration in which the heat generating unit is provided inside the accommodation chamber S (inside the housing 10), the heat generated in the heat generating unit is less likely to be transmitted to the first device, and it is possible to further suppress changes in the characteristics of light transmitted inside the housing 10 due to heat generation by the heat generating unit, and ultimately changes in the optical characteristics of the optical module 100G.

[0079] Furthermore, a cavity 62G is provided in the feedthrough 21E at a position outside the housing 10. The cavity 62G is provided in the heat transfer path from the modulator driver 31 or the transimpedance amplifier 32, which serves as a heat-generating portion, to the first device, and can suppress heat transfer from the heat-generating portion to the first device. Therefore, the cavity 62G can also suppress changes in the characteristics of light transmitted within the housing 10 due to heat generation by the heat-generating portion, and ultimately changes in the optical characteristics of the optical module 100G.

[0080] While the embodiments of the present invention have been described above, they are merely examples and are not intended to limit the scope of the invention. The above embodiments can be implemented in various other forms, and various omissions, substitutions, combinations, and modifications can be made without departing from the spirit of the invention. Furthermore, the specifications of each configuration, shape, and the like (structure, type, direction, model, size, length, width, thickness, height, number, arrangement, position, material, etc.) can be modified as appropriate.

[0081] For example, the cross-sectional shape of the cavity is not limited to a rectangle, but may be various shapes such as an oval, a circle, a triangle, a trapezoid, or a V-shape. [Explanation of symbols]

[0082] 10...Housing (first member, fixed member) 10a…Bottom wall 10a1...back side 10b...peripheral wall 10c…Ceiling wall 10d...Window material 21, 21E... Feedthrough (first member, support member) 21a...conductor 21b...conductor 21c...Cover conductor 22...Support base (first member) 23…Intervening member 31...Modulator driver (heat generating part) 32...Transimpedance amplifier (device) 33...Modulator (device) 34...Coherent mixer (device) 35...Chip-on-submount (device, heat generating part) 36...Bonding wire 41, 42...TEC (device) 51...Lens (optical component) 52...Adhesive 61,61C1,61C2…Cavity 61a...Opening 61b...heat transfer layer 61c…Opening 62,62C,62G…Cavity 71...External wiring 72...Joint part 81... Mounting board (first member, fixing member) 82...Joint part 91...Heat conduction block (heat transfer member) 92...Heat conduction sheet (heat transfer material) 93,94...Heat sink 100, 100A to 100G...Optical module P1…first part S…Containment room X…direction Y...direction Z…direction

Claims

1. a housing in which light is transmitted; A heat generating portion; a device provided within the housing, the device changing the characteristics of light transmitted within the housing when heated; a first member thermally connected to the heat generating portion and the device; Equipped with a cavity is provided in the first member in a heat transfer path from the heat generating portion to the device in a state in which convection heat transfer into the housing is suppressed; An optical module, wherein the first member has a cavity positioned outside the housing as the cavity.

2. a housing in which light is transmitted; A heat generating portion; a device provided within the housing, the device changing the characteristics of light transmitted within the housing when heated; a first member thermally connected to the heat generating portion and the device; Equipped with a cavity is provided in the first member in a heat transfer path from the heat generating portion to the device in a state in which convection heat transfer into the housing is suppressed; The optical module includes a heat generating portion positioned outside the housing.

3. a housing in which light is transmitted; A heat generating portion; a device provided within the housing, the device changing the characteristics of light transmitted within the housing when heated; a first member thermally connected to the heat generating portion and the device; Equipped with a cavity is provided in the first member in a heat transfer path from the heat generating portion to the device in a state in which convection heat transfer into the housing is suppressed; a joining portion for joining a plurality of members, the joining portion being heated during joining; the joint is located outside the housing, The optical module, wherein the first member has a cavity that is a closed space located outside the housing as the cavity.

4. a housing in which light is transmitted; A heat generating portion; a device provided within the housing, the device changing the characteristics of light transmitted within the housing when heated; a first member provided in contact with the inner surface of the housing and thermally connected to the heat generating portion and the device; Equipped with a cavity is provided in the first member in a heat transfer path from the heat generating portion to the device in a state in which convection heat transfer into the housing is suppressed; An optical module configured such that a heat transfer path is formed from the heat generating portion to the device via the housing and the first member, and the cavity extends from the first member to the housing and is open to the outside of the housing, thereby suppressing heat transfer from the heat generating portion to the device.

5. 5. The optical module according to claim 1, further comprising a joint portion for joining a plurality of members, the joint portion being heated during joining.

6. 6. The optical module according to claim 1, wherein the housing is hermetically sealed.

7. 7. The optical module according to claim 1, wherein the first member has a cavity that is open to the outside of the housing as the cavity.

8. 8. The optical module according to claim 1, wherein the cavity in the first member is a closed space.

9. the first member is provided with a cavity having an opening into the housing, 9. The optical module according to claim 1, further comprising a covering member that at least partially covers the opening.

10. The optical module according to claim 9 , wherein the covering member is at least one of a second member bonded to the first member and an adhesive that bonds the first member and the second member.

11. 11. The optical module according to claim 1, wherein the first member is provided with a cavity that is at least partially located within the housing as the cavity.

12. the heat generating portion and the device are spaced apart in a first direction, 12. The optical module according to claim 1, wherein the first member has a plurality of cavities spaced apart in the first direction as the cavities.

13. the heat generating portion and the device are spaced apart in a first direction, 13. The optical module according to claim 1, wherein the first member has a plurality of cavities spaced apart from one another in a second direction intersecting the first direction.

14. 14. The optical module according to claim 1, wherein the first member has a cavity provided on its inner surface with a heat transfer layer having a higher thermal conductivity than the first member.

15. The device includes a plurality of devices, 15. The optical module according to claim 1, wherein the first member has a cavity positioned on a heat transfer path between the plurality of devices.

16. 16. The optical module according to claim 1, wherein the heat generating portion is located within the housing.

17. 17. The optical module according to claim 1, wherein the heat generating portion is an electrically operated heat generating portion.

18. The optical module according to claim 17 , wherein the heat generating portion is flip-chip mounted to the first member.

19. 19. The optical module according to claim 1, wherein the housing is the first member.

20. 20. The optical module according to claim 1, wherein the first member comprises a support member for supporting the device.

21. The optical module according to claim 20 , wherein the first member comprises a fixing member fixed to the support member.

22. 22. The optical module according to claim 1, wherein the first member is made of a porous material.

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