Optical communication device
The optical communication device achieves efficient heat dissipation through natural coolant circulation within the device, simplifying the configuration by eliminating the need for pumps and pipes.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- MITSUBISHI ELECTRIC CORP
- Filing Date
- 2025-04-07
- Publication Date
- 2026-07-16
AI Technical Summary
Existing optical communication devices with semiconductor light-emitting elements require pumps and pipes to circulate coolant for heat dissipation, complicating their configuration.
An optical communication device design that circulates coolant within an internal space without the need for a pump or pipe, using through holes in the stem and cap to facilitate natural convection and circulation between the optical module and a coolant tank.
Effectively dissipates heat from optical elements by circulating coolant, improving thermal management without the complexity of pumps and pipes.
Smart Images
Figure JP2025013839_16072026_PF_FP_ABST
Abstract
Description
Optical communication device
[0001] The present disclosure relates to an optical communication device.
[0002] Patent Document 1 discloses a semiconductor light-emitting element using a TO (Transistor Outline)-CAN type optical module. The semiconductor light-emitting element disclosed in Patent Document 1 supports an optical element on a stem via a copper block, and attaches a cap to the stem so as to wrap the optical element and the copper block. Further, the semiconductor light-emitting element disclosed in Patent Document 1 fills the internal space formed by the stem and the cap with a coolant. Then, the semiconductor light-emitting element disclosed in Patent Document 1 improves the heat dissipation of the optical element by circulating the coolant filled in the internal space between the outside of the semiconductor light-emitting element.
[0003] Japanese Patent Laid-Open No. 7-99372
[0004] The semiconductor light-emitting element disclosed in Patent Document 1 includes a pump and a pipe connecting the pump and the internal space in order to circulate the coolant filled in the internal space. Thus, providing the pump and the pipe may complicate the configuration of the semiconductor light-emitting element.
[0005] The present disclosure is made to solve the above problems, and an object thereof is to provide an optical communication device capable of dissipating heat of an optical element by circulating the coolant filled in the internal space without providing a pump and a pipe.
[0006] The optical communication device according to the present disclosure includes an optical module in which a first coolant fills an internal space in which an optical element is accommodated, a coolant tank in which the optical module is immersed in a second coolant stored therein, an optical coupling member provided in the coolant tank for transmitting and receiving light to and from the optical element, and a through hole provided in the optical module and located below the liquid level of the second coolant for communicating between the internal space and the inside of the coolant tank.
[0007] According to the present disclosure, heat dissipation of the optical element can be performed by circulating the coolant filled in the internal space without providing a pump and a pipe.
[0008] This is a longitudinal cross-sectional view of an optical communication device according to Embodiment 1. This is a longitudinal cross-sectional view of an optical communication device according to Embodiment 2. This is a longitudinal cross-sectional view of an optical communication device according to Embodiment 3. This is a longitudinal cross-sectional view of an optical communication device according to Embodiment 4. This is a plan view of an optical communication device according to Embodiment 4. Figure 6A is a perspective view of a cylindrical lead pin. Figure 6B is a perspective view of a solid lead pin. This is a longitudinal cross-sectional view of an optical communication device according to Embodiment 5.
[0009] To provide a more detailed explanation of this disclosure, the forms for implementing this disclosure will be described below with reference to the attached drawings.
[0010] Embodiment 1. An optical communication device 100 according to Embodiment 1 will be described with reference to Figure 1. Figure 1 is a longitudinal cross-sectional view of the optical communication device 100 according to Embodiment 1.
[0011] The optical communication device 100 according to Embodiment 1 shown in Figure 1 is an optical transmitting device for transmitting light, or an optical receiving device for receiving light. The optical communication device 100 according to Embodiment 1 includes an optical module 10A and a cooling liquid tank 50.
[0012] As shown in Figure 1, the optical module 10A includes a stem 11, a block 12, a submount substrate 13, an optical element 14, wires 15, lead pins 16a and 16b, a cap 17, and a lens 18. The optical module 10A only needs to include at least the stem 11, submount substrate 13, optical element 14, wires 15, lead pins 16a and 16b, and cap 17. Furthermore, the optical module 10A may also include electronic components such as a photodetector for optical power monitoring, a Peltier element for adjusting the temperature of the optical element 14, or a capacitor for improving electrical characteristics.
[0013] The stem 11 is formed in a cylindrical shape. The stem 11 is positioned so that its central axis extends in the vertical direction. The stem 11 is made of a metallic material such as copper, iron, aluminum, or nickel alloy. The surface of the stem 11 may also be plated. The stem 11 has one or more through holes 11a. The through holes 11a penetrate the stem 11 in the vertical direction. The through holes 11a are positioned above the optical element 14, which will be described later. Figure 1 shows an example in which the stem 11 has one through hole 11a.
[0014] Block 12 is provided on the lower surface of the stem 11. Block 12 is formed, for example, in the shape of a rectangular parallelepiped. Block 12 is made of a metallic material such as copper, iron, aluminum, or nickel alloy. The surface of block 12 may also be plated. Therefore, block 12 also serves as a heat transfer path from the optical element 14 (described later) to the stem 11.
[0015] The optical element 14 is provided on the surface of the block 12 via a submount substrate 13. The optical element 14 is formed, for example, in a flat plate shape, and one of its planes constitutes either a light-emitting end face or a light-receiving end face.
[0016] For example, the surface of the submount substrate 13 is provided with an optical element 14 and a metal pattern for wiring. The optical element 14 and the metal pattern are electrically connected to each other. The submount substrate 13 is, for example, a ceramic substrate. The optical element 14 is, for example, a light-emitting element such as a semiconductor laser that converts electricity into light, or a light-receiving element such as a photodiode that converts light into electricity.
[0017] Furthermore, if the optical element 14 is a light-emitting element, the optical module 10A becomes a light source module, and the optical communication device 100 becomes an optical transmission device. Also, if the optical element 14 is a light-receiving element, the optical module 10A becomes a light-receiving module, and the optical communication device 100 becomes an optical reception device.
[0018] Multiple lead pins 16a and 16b are supported by passing through the stem 11 in the vertical direction. The lead pins 16a and 16b are made of a metal material such as copper, iron, aluminum, or nickel alloy. The surfaces of the lead pins 16a and 16b may also be plated. Figure 1 shows an example in which the optical module 10A has three lead pins 16a and 16b. In this case, two lead pins 16a are electrically connected to the optical element 14, and one lead pin 16b is electrically connected to the stem 11, which is ground.
[0019] Specifically, the lower ends of the two lead pins 16a each pass through the stem 11 and are positioned inside the cap 17, which will be described later. Furthermore, the lower ends of the two lead pins 16a are electrically connected to the metal pattern of the submount substrate 13 via a metal wire 15 made of gold or aluminum, etc. The connection by wire 15 may be replaced with brazing to improve the high-frequency characteristics necessary for communication. Thus, the lower ends of the two lead pins 16a are electrically connected to the optical element 14. On the other hand, the lower end of one lead pin 16b is joined to the stem 11. The upper ends of the lead pins 16a and 16b protrude upward from the upper surface of the stem 11 and are electrically connected to an external device (not shown) provided outside the optical communication device 100.
[0020] The cap 17, together with the stem 11, forms the outer shell of the optical module 10A. The cap 17 is formed in a bottomed cylindrical shape with an open upper end and a bottom lower end. The opening of the cap 17 is sealed and joined to the lower surface of the stem 11. At this time, the cap 17 is positioned to cover the lower ends of the block 12, submount substrate 13, optical element 14, and lead pins 16a from below. As a result, an internal space 19 is formed by the lower surface of the stem 11 and the inner surface of the cap 17. The lower ends of the block 12, submount substrate 13, optical element 14, and lead pins 16a are housed within this internal space 19. The through hole 11a of the stem 11 is in communication with the inside of this internal space 19. The cap 17 is made of a metal material such as copper, iron, aluminum, or nickel alloy. The surface of the cap 17 may also be plated.
[0021] The lens 18 is located at the bottom of the cap 17. Therefore, the lens 18, together with the cap 17, forms the internal space 19. The lens 18 faces the optical element 14 attached to the block 12 in the vertical direction. The lens 18 is, for example, an aspherical lens made of glass, but is not limited to that; it is sufficient if optical coupling between the optical element 14 and the optical fiber 51, which will be described later, can be achieved. As an optical coupling member, a glass plate may be provided instead of the lens 18. Furthermore, the optical communication device 100 may also be provided with other lenses facing the lens 18 on the outside of the optical module 10A.
[0022] The internal space 19 of the optical module 10A is filled with coolant 61. The coolant 61 is injected into the internal space 19 through the through hole 11a of the stem 11. The coolant 61 is for cooling the optical element 14, in other words, for dissipating heat from the optical element 14. The optical element 14 attached to the block 12 is in contact with the coolant 61.
[0023] In contrast, as shown in Figure 1, the coolant tank 50 contains coolant 62. The coolant 62 is for cooling the optical module 10A, or in other words, for dissipating heat from the optical element 14. The coolant tank 50 is designed so that the optical module 10A can be immersed in the coolant tank 50 containing the coolant 62. At this time, the optical module 10A is immersed in the coolant tank 50 until the coolant 62 exceeds the upper end of the through hole 11a. That is, the upper end of the through hole 11a is positioned below the liquid level of the coolant 62.
[0024] Furthermore, the cooling liquid tank 50 has an optical fiber 51. One end of the optical fiber 51 faces the light-emitting end face or light-receiving end face of the optical element 14. The other end of the optical fiber 51 extends outside the cooling liquid tank 50. In Figure 1, the optical fiber 51 is supported by penetrating the cooling liquid tank 50, but it is not limited to this. For example, the optical fiber 51 may pass through the surface of the cooling liquid 62 stored in the cooling liquid tank 50 and be placed in the cooling liquid 62.
[0025] Therefore, if the optical element 14 is a light-emitting element, the light emitted from the optical element 14 passes through the lens 18 and is focused toward one end of the optical fiber 51. The light focused toward one end of the optical fiber 51 is then transmitted through the optical fiber 51 toward the outside of the optical communication device 100. If the optical element 14 is a light-receiving element, the light transmitted from outside the optical communication device 100 via the optical fiber 51 passes through the lens 18 and is focused toward the end face of the optical element 14.
[0026] Coolants 61 and 62 are coolants having a thermal conductivity higher than that of vacuum or air, and also possessing insulating properties (non-conductive properties). Coolants 61 and 62 can be of the same type or equivalent. Coolants 61 and 62 are, for example, fluorine-based inert liquids, hydrocarbon-based liquids, or silicone-based liquids. Coolant 61 is the first coolant, and coolant 62 is the second coolant.
[0027] In the case of manufacturing the optical communication device 100, the coolant 61 is injected into the internal space 19 of the optical module 10A through the through hole 11a of the stem 11. Then, with the internal space 19 filled with the coolant 61, the optical module 10A is immersed in the coolant tank 50 where the coolant 62 is stored. As a result, the coolant 61 filling the internal space 19 of the optical module 10A and the coolant 62 stored in the coolant tank 50 can circulate and mix with each other through the through hole 11a of the stem 11.
[0028] Therefore, the optical element 14 dissipates heat through the block 12 and stem 11, and also through the coolant 61. At this time, the coolant 61, which has become hot due to the heat generated by the optical element 14, rises within the internal space 19 of the optical module 10A and flows into the coolant tank 50 through the through hole 11a of the stem 11. Also, the low-temperature coolant 62 stored in the coolant tank 50 flows into the internal space 19 of the optical module 10A through the through hole 11a of the stem 11. In other words, the through hole 11a of the stem 11 is an injection hole for the coolant 61 into the internal space 19 during the manufacturing of the optical communication device 100, and becomes a flow path through which the coolants 61 and 62 pass each other when the optical communication device 100 is in operation.
[0029] As described above, the optical communication device 100 according to Embodiment 1 comprises an optical module 10A in which a cooling liquid 61 fills an internal space 19 in which an optical element 14 is housed; a cooling liquid tank 50 in which the optical module 10A is immersed in a cooling liquid 62 stored inside; an optical fiber 51 provided in the cooling liquid tank 50 for transmitting and receiving light with the optical element 14; and a through hole 11a provided in the optical module 10A, located below the liquid surface of the cooling liquid 62, and communicating between the internal space 19 and the inside of the cooling liquid tank 50. Therefore, the optical communication device 100 according to Embodiment 1 can dissipate heat from the optical element 14 by circulating the cooling liquid 61 filled in the internal space 19 without the need for a pump or piping.
[0030] In the optical communication device 100 according to Embodiment 1, the through hole 11a is positioned above the optical element 14. Therefore, the optical communication device 100 according to Embodiment 1 can easily allow the coolant 61, which has been heated by the heat generated by the optical element 14, to flow out from the internal space 19.
[0031] In the optical communication device 100 according to Embodiment 1, the optical module 10A includes a stem 11 that supports an optical element 14 and has a through hole 11a, and a cap 17 provided on the stem 11 so as to cover the periphery of the optical element 14 and forming an internal space 19 between the stem 11 and the cap 17. Therefore, in the optical communication device 100 according to Embodiment 1, by providing a through hole 11a in the stem 11 that forms the upper surface of the internal space 19, the coolant 61 that has been heated by the heat generated by the optical element 14 can be easily discharged from inside the internal space 19.
[0032] Embodiment 2. An optical communication device 200 according to Embodiment 2 will be described with reference to Figure 2. Figure 2 is a longitudinal cross-sectional view of the optical communication device 200 according to Embodiment 1. Components having the same functions as those described in the above-described embodiments are denoted by the same reference numerals, and their descriptions are omitted.
[0033] The optical communication device 200 according to Embodiment 2 shown in Figure 2 is equipped with an optical module 10B in place of the optical module 10A of the optical communication device 100 according to Embodiment 1 shown in Figure 1. Furthermore, the optical module 10B according to Embodiment 2 has a through hole 17a added to the configuration of the optical module 10A. The through hole 17a is a lower through hole.
[0034] As shown in Figure 2, the optical module 10B is immersed inside a coolant tank 50 containing coolant 62. The cap 17 has a through hole 17a. The installation height of the through hole 17a is lower than the installation height of the through hole 11a. The through hole 17a connects the internal space 19 to the inside of the coolant tank 50.
[0035] Therefore, in the optical communication device 200 according to Embodiment 2, the coolant 61, which has become hot due to the heat generated by the optical element 14 in the internal space 19, flows out into the coolant tank 50 through the through hole 11a, which has a high installation height. On the other hand, the low-temperature coolant 62 stored in the coolant tank 50 flows into the internal space 19 through the through hole 17a, which has a low installation height. As a result, in the optical communication device 200 according to Embodiment 2, the coolants 61 and 62 circulate naturally. Thus, the heat dissipation of the optical element 14 is improved.
[0036] Furthermore, the optical module 10B has through holes 11a and 17a that communicate with the internal space 19 in an unsealed state, which helps to suppress mechanical deformation of the cap 17 in response to changes in ambient air pressure or temperature.
[0037] As described above, in the optical communication device 200 according to Embodiment 2, the optical module 10B has a through hole 17a of the cap 17 which is positioned below the through hole 11a of the stem 11. Therefore, the optical communication device 200 according to Embodiment 2 can promote natural convection of the cooling liquids 61 and 62, thereby improving the heat dissipation of the optical element 14.
[0038] Embodiment 3. An optical communication device 300 according to Embodiment 3 will be described with reference to Figure 3. Figure 3 is a longitudinal cross-sectional view of the optical communication device 300 according to Embodiment 3. Components having the same functions as those described in the above embodiments are denoted by the same reference numerals, and their descriptions are omitted.
[0039] The optical communication device 300 according to Embodiment 3 shown in Figure 3 is equipped with an optical module 10C in place of the optical module 10A of the optical communication device 100 according to Embodiment 1 shown in Figure 1. Furthermore, the optical module 10C according to Embodiment 3 has the configuration of the optical module 10A according to Embodiment 1 with the addition of a temporary sealing member 21.
[0040] The temporary sealing member 21 can seal the through hole 11a of the stem 11 from the upper surface side of the stem 11, that is, from the outside of the internal space 19. The temporary sealing member 21 is formed in a plug shape that can be inserted into the through hole 11a or in a flat plate shape that can cover the through hole 11a. FIG. 3 shows an example of the temporary sealing member 21 having a plug shape.
[0041] For example, when storing or transporting the optical module 10C in which the coolant 61 is filled in the internal space 19, the temporary sealing member 21 temporarily seals the through hole 11a of the stem 11. Next, the temporary sealing member 21 is removed from the through hole 11a of the stem 11 before or after putting the optical module 10C in which the coolant 61 is filled in the internal space 19 into the coolant tank 50. At this time, it does not matter whether the coolant 62 is stored in the coolant tank 50 or not. That is, the temporary sealing member 21 is removed before driving the optical communication device 300.
[0042] Therefore, the temporary sealing member 21 can prevent the coolant 61 filled in the internal space 19 from leaking out through the through hole 11a during storage or transportation of the optical module 10C. As a result, the coolant 61 can be filled around the optical element 14, so that oxidation or moisture absorption due to air exposure in the optical element 14 can be suppressed.
[0043] Here, the temporary sealing member 21 may be formed of a material that can be dissolved when it comes into contact with the coolant 62. For this reason, when the optical module 10C in which the through hole 11a is sealed by the temporary sealing member 21 is installed inside the coolant tank 50, the temporary sealing member 21 naturally dissolves due to the coolant 62 stored inside the coolant tank 50. As a result, the operation of removing the temporary sealing member 21 is eliminated.
[0044] For example, when the coolant 62 is a hydrocarbon-based liquid, the temporary sealing member 21 is formed of a hydrocarbon-based material such as ethylene propylene diene rubber. When the coolant 62 is a silicone-based liquid, the temporary sealing member 21 is formed of a silicone-based material such as silicone rubber.
[0045] Further, the temporary sealing member 21 may be formed of a sealing material that can be removed by stress. Therefore, when the optical module 10C in a state where the through hole 11a is sealed by the temporary sealing member 21 is installed inside the coolant tank 50, the temporary sealing member 21 is naturally removed from the through hole 11a by being exposed to the flow of the coolant 62. As a result, the operation of removing the temporary sealing member 21 is eliminated.
[0046] Further, the temporary sealing member 21 may be formed of a material that can be melted or lose its sealing function when held at a high temperature. For example, it is assumed that the temperature of the coolants 61 and 62 during driving of the optical module 10C rises to around 50 degrees while the room temperature during storage or transportation of the optical module 10C is about 25 degrees. Therefore, the temporary sealing member 21 naturally melts due to the temperature rise of the coolants 61 and 62. As a result, the operation of removing the temporary sealing member 21 is eliminated.
[0047] As described above, the optical communication device 300 according to Embodiment 3 includes a temporary sealing member 21 that closes the through hole 11a of the stem 11 from the outside of the internal space 19 in a state where the internal space 19 is filled with the coolant 61. Therefore, the optical communication device 300 according to Embodiment 3 can prevent the coolant 61 filled in the internal space 19 from leaking out through the through hole 11a during storage or transportation of the optical module 10C.
[0048] In the optical communication device 300 according to Embodiment 3, the temporary sealing member 21 is formed of a material that can be melted when it comes into contact with the coolant 62. Therefore, the optical communication device 300 according to Embodiment 3 can eliminate the operation for the operator to remove the temporary sealing member 21.
[0049] In the optical communication device 300 according to Embodiment 3, the temporary sealing member 21 is formed of a material that can be removed when exposed to the flow of the coolant 62. Therefore, the optical communication device 300 according to Embodiment 3 can eliminate the operation for the operator to remove the temporary sealing member 21.
[0050] In the optical communication device 300 according to Embodiment 3, the temporary sealing member 21 is made of a material that can be dissolved by the temperature increase of the cooling liquids 61 and 62. Therefore, the optical communication device 300 according to Embodiment 3 eliminates the need for an operator to remove the temporary sealing member 21.
[0051] Embodiment 4. The optical communication device 400 according to Embodiment 4 will be described with reference to Figures 4 to 6. Figure 4 is a longitudinal cross-sectional view of the optical communication device 400 according to Embodiment 4. Figure 5 is a plan view of the optical communication device 400 according to Embodiment 4. Figure 6A is a perspective view of a cylindrical lead pin 31. Figure 6B is a perspective view of a solid lead pin 32. Components having the same function as those described in the above embodiments are denoted by the same reference numerals, and their descriptions are omitted.
[0052] The optical communication device 400 according to Embodiment 4 shown in Figure 4 is equipped with an optical module 10D in place of the optical module 10A of the optical communication device 100 according to Embodiment 1 shown in Figure 1. Furthermore, the optical module 10D according to Embodiment 4 has lead pins 31 and 32 in place of the lead pins 16a and 16b of the optical module 10A according to Embodiment 1. Note that the optical module 10D according to Embodiment 4 does not have a through hole 11a in the stem 11.
[0053] As shown in Figure 4, the lead pins 31 and 32 are supported by passing through the stem 11 in the vertical direction. The two lead pins 31 are electrically connected to the optical element 14. The lead pin 32 is electrically connected to the stem 11, which is ground.
[0054] Specifically, the lower ends of the two lead pins 31 pass through the stem 11 and are located inside the cap 17. Furthermore, the lower ends of the two lead pins 31 are electrically connected to the metal pattern on the submount substrate 13 via a metal wire 15. Thus, the lower ends of the two lead pins 31 are electrically connected to the optical element 14. On the other hand, the lower end of one lead pin 31 is joined to the stem 11. The upper ends of the lead pins 31 and 32 protrude upward from the upper surface of the stem 11 and are electrically connected to an external device (not shown) located outside the optical communication device 400.
[0055] As shown in Figures 4, 5, and 6A, the lead pins 31 are formed in a cylindrical shape. Therefore, each lead pin 31 has a through hole 31a. The through holes 31a of the lead pins 31 are positioned above the optical element 14. Furthermore, the through holes 31a of the lead pins 31 communicate with the internal space 19. In this way, the optical module 10D, by having cylindrical lead pins 31, can use their through holes 31a as injection holes for the coolant 61.
[0056] Furthermore, as shown in Figure 5, the lead pin 31 is sealed to the stem 11 via a cylindrical sealing glass 33. Therefore, the optical module 10D can calculate the impedance of the lead pin 31 based on the diameter of the lead pin 31, the diameter of the through hole in the stem 11 through which the lead pin 31 and the sealing glass 33 pass, and the dielectric constant of the sealing glass 33.
[0057] Furthermore, as shown in Figure 4, the upper end of the lead pin 31 is positioned to protrude upward from the upper surface of the stem 11. The upper end of the lead pin 31 is located within the coolant 62 stored in the coolant tank 50. That is, the upper end of the lead pin 31 is located below the liquid level of the coolant 62. For this reason, a temporary sealing member 34 can be attached to the upper end of the lead pin 31. As a result, the temporary sealing member 34 can seal the upper end of the through hole 31a in the lead pin 31 from the outside.
[0058] On the other hand, as shown in Figures 4, 5, and 6B, the lead pin 32 is formed in a solid shape. That is, the lead pin 32 does not have a through hole 31a.
[0059] For example, when storing or transporting an optical module 10D with the coolant 61 filling its internal space 19, the temporary sealing member 34 temporarily seals the through-hole 31a of the lead pin 31. Then, before or after placing the optical module 10D, with the coolant 61 filling its internal space 19, into the coolant tank 50, the temporary sealing member 34 is removed from the through-hole 31a of the lead pin 31. The upper end or outer surface of the lead pin 31 is then electrically connected to the external device provided outside the optical communication device 400.
[0060] Therefore, the temporary sealing member 34 can prevent the coolant 61 filling the internal space 19 from leaking out through the through-hole 31a of the lead pin 31 when the optical module 10D is stored or transported. As a result, the coolant 61 can be filled around the optical element 14, thereby suppressing oxidation or moisture absorption of the optical element 14 due to exposure to air.
[0061] Furthermore, the optical module 10D does not require a through-hole in the stem 11 or cap 17 that communicates with the internal space 19. Therefore, the optical module 10D can accommodate cases where a through-hole cannot be provided in the stem 11 due to design constraints, and it can prevent a decrease in the mechanical strength of the cap 17.
[0062] Then, when the optical module 10D is immersed in the coolant tank 50 in which the coolant 62 is stored, the coolant 61 filling the internal space 19 of the optical module 10A and the coolant 62 stored inside the coolant tank 50 can circulate and mix with each other through the through-hole 31a of the lead pin 31.
[0063] As described above, in the optical communication device 400 according to Embodiment 4, the optical module 10D includes a stem 11 that supports the optical element 14, a cap 17 provided on the stem 11 so as to cover the periphery of the optical element 14 and forming an internal space 19 between the stem 11 and the cap 17, and a lead pin 31 that penetrates the stem 11, is electrically connected to the optical element 14, and has a through hole 31a that connects the internal space 19 to the inside of the cooling liquid tank 50. Therefore, the optical communication device 400 according to Embodiment 3 can accommodate cases where a through hole cannot be provided in the stem 11 due to design constraints, and can prevent a decrease in the mechanical strength of the cap 17.
[0064] Embodiment 5. An optical communication device 500 according to Embodiment 5 will be described with reference to Figure 7. Figure 7 is a longitudinal cross-sectional view of the optical communication device 500 according to Embodiment 5. Components having the same functions as those described in the above embodiments are denoted by the same reference numerals, and their descriptions are omitted.
[0065] The optical communication device 500 according to Embodiment 5 shown in Figure 7 is equipped with an optical module 10E in place of the optical module 10D of the optical communication device 400 according to Embodiment 4 shown in Figure 4. Furthermore, the optical module 10E according to Embodiment 5 is the optical module 10D according to Embodiment 4 with the addition of a wiring board 41.
[0066] As shown in Figure 7, the optical module 10E has a wiring board 41. The wiring board 41 is provided on the upper surface of the stem 11. The wiring board 41 is also electrically connected to an external device (not shown) provided outside the optical communication device 500. At this time, the lead pins 31 and 32 and the wiring board 41 are electrically connected via a bonding member such as solder. Therefore, the optical module 10E can easily electrically connect the optical element 14 to the external device via the lead pins 31 and the wiring board 41.
[0067] As described above, the optical communication device 500 according to Embodiment 5 includes a wiring board 41 that is electrically connected to the lead pins 31 and provided on the stem 11. Therefore, the optical communication device 500 according to Embodiment 5 can easily electrically connect the optical element 14 to the external device via the lead pins 31 and the wiring board 41.
[0068] Within the scope of this disclosure, it is possible to freely combine the embodiments, modify any component in each embodiment, or omit any component in each embodiment.
[0069] The optical communication device according to this disclosure is suitable for use in optical communication devices and the like, as it is capable of dissipating heat from optical elements by circulating the coolant filled in the internal space without the need for a pump or piping, by providing through holes that connect the internal space of the optical module to the inside of the coolant tank.
[0070] 10A, 10B, 10C, 10D, 10E Optical module, 11 Stem, 11a Through hole, 12 Block, 12a Mounting recess, 13 Submount substrate, 14 Optical element, 15 Wire, 16a, 16b Lead pins, 17 Cap, 17a Through hole, 18 Lens, 19 Internal space, 21 Temporary sealing member, 31 Lead pin, 31a Through hole, 32 Lead pin, 33 Sealing glass, 34 Temporary sealing member, 41 Wiring substrate, 50 Cooling liquid tank, 51 Optical fiber, 61, 62 Cooling liquid, 100, 200, 300, 400, 500 Optical communication device.
Claims
1. An optical communication device comprising: an optical module in which an internal space containing an optical element is filled with a first coolant; a coolant tank in which the optical module is immersed in a second coolant stored inside; an optical coupling member provided in the coolant tank for transmitting and receiving light with the optical element; and a through hole provided in the optical module, located below the liquid level of the second coolant, and communicating the internal space with the inside of the coolant tank.
2. The optical communication device according to claim 1, characterized in that the through hole is positioned above the optical element.
3. The optical communication device according to claim 2, characterized in that the optical module has a lower through-hole located below the through-hole.
4. The optical communication device according to any one of claims 1 to 3, characterized in that the optical module comprises a stem that supports the optical element and has the through hole, and a cap provided on the stem so as to cover the periphery of the optical element and forming the internal space between the stem and the cap.
5. The optical communication device according to any one of claims 1 to 3, wherein the optical module comprises a stem supporting the optical element; a cap provided on the stem so as to cover the periphery of the optical element and forming the internal space between the stem and the cap; and a lead pin having a through hole that penetrates the stem, is electrically connected to the optical element, and communicates the internal space with the cooling liquid tank.
6. The optical communication device according to claim 5, characterized in that it comprises a wiring board electrically connected to the lead pins and provided on the stem.
7. The optical communication device according to any one of claims 1 to 6, characterized in that it comprises a temporary sealing member that closes the through hole from the outside of the internal space when the internal space is filled with the first cooling liquid.
8. The optical communication device according to claim 7, characterized in that the temporary sealing member is made of a material that can dissolve upon contact with the second cooling liquid.
9. The optical communication device according to claim 7, characterized in that the temporary sealing member is made of a material that can be removed when exposed to the flow of the second coolant.
10. The optical communication device according to claim 7, characterized in that the temporary sealing member is made of a material that can be dissolved by the temperature increase of the first coolant and the second coolant.