Optical module and light source device

Abstract

This optical module includes, for example: a housing in which a through-hole is formed; a light transmission unit housed in the housing; a control board on which a drive circuit for driving the light transmission unit is mounted; a connection part that is optically and electrically connected to an external device; and an optical fiber that connects the light transmission unit and the connection part to each other. In the optical module, the housing may be constituted by a lower housing and an upper housing covering an opening of the lower housing. Due to this configuration, provided are, for example, an optical module and a light source device that are capable of dissipating the heat of a drive circuit for driving a TOSA.

Description

Optical module and light source device

[0001] The present invention relates to an optical module and a light source device.

[0002] An optical module equipped with a TOSA (Transmitter Optical Sub-Assembly) has been disclosed (see, for example, Patent Document 1). Patent Document 1 describes that the heat dissipation surface of the TOSA is in direct contact with a heat sink to improve heat dissipation efficiency.

[0003] Japanese Patent Application Laid-Open No. 2020-98249

[0004] However, the technology of Patent Document 1 does not allow heat from the drive circuit that drives the TOSA to be dissipated, which is undesirable because a rise in the temperature of the drive circuit leads to a rise in the temperature of the semiconductor laser of the TOSA.

[0005] Therefore, one object of the present invention is to provide an optical module and a light source device that can dissipate heat from a drive circuit that drives a TOSA, for example.

[0006] The optical module of the present invention comprises, for example, a housing having a through hole formed therein, an optical transmitting unit accommodated in the housing, a control board on which a drive circuit for driving the optical transmitting unit is mounted, a connection unit optically and electrically connected to an external device, and an optical fiber connecting the optical transmitting unit and the connection unit.

[0007] In the optical module, the housing may be configured with a lower housing.

[0008] In the optical module, the through hole may be formed in an upper surface or a side surface of the housing.

[0009] In the optical module, the through hole may be formed in the vicinity of the drive circuit.

[0010] In the optical module, the through hole may be formed in the upper surface of the housing, and may be formed closer to the connection section than the optical transmitter section.

[0011] The optical module may be configured such that a plate-shaped air-cooling fin extending along the longitudinal direction of the housing is provided on an upper surface of the housing.

[0012] In the optical module, the through hole may be formed at a position farther away from the connection portion than the drive circuit.

[0013] In the optical module, the through-hole may be formed on the upper surface of the housing so as to be positioned between the cooling fins.

[0014] In the optical module, the optical fiber may be accommodated in the housing.

[0015] In the optical module, the optical fiber may be routed between the control board and the upper housing.

[0016] The light source device of the present invention comprises, for example, the optical module, a case that holds the optical module so that the connection portion is located inside, and air-cooling fins attached to the case, and the through hole is formed outside the case further than the drive circuit.

[0017] The light source device may be fixed to the case and include a cage that holds the optical module, and the upper surface of the cage may be provided with plate-shaped air-cooling fins that extend along the longitudinal direction of the housing.

[0018] In the light source device, the cage may have a through hole formed in a position overlapping the through hole of the housing.

[0019] According to the present invention, for example, an optical module and a light source device capable of dissipating heat from a drive circuit that drives a TOSA can be obtained.

[0020] FIG. 1 is a schematic configuration diagram of a light source device including an optical module according to an embodiment. FIG. 2 is a perspective view of the optical module shown in FIG. 1. FIG. 3 is an exploded view of the optical module. FIG. 4 is a schematic cross-sectional view of the optical module. FIG. 5 is a schematic plan view of the optical module. FIG. 6 is a diagram showing the results of a simulation of wind speed in the optical module. FIG. 7 is a diagram showing the results of a simulation of temperature in the optical module. FIG. 8 is a diagram showing the results of a simulation of air temperature in the optical module. FIG. 9 is a plan view of an upper housing of an optical module according to a modified example. FIG. 10 is a diagram showing the results of a simulation of wind speed in the optical module. FIG. 11 is a diagram showing the results of a simulation of wind speed in the optical module. FIG. 12 is a diagram showing the results of a simulation of wind speed in the optical module. FIG. 13 is a diagram showing the results of a simulation of wind speed in the optical module. FIG. 14 is a diagram showing the results of a simulation of wind speed in the optical module. FIG. 15 is a diagram showing the results of a simulation of wind speed in the optical module. FIG. 16 is a diagram showing the results of a simulation of wind speed in the optical module. Fig. 17 is a diagram showing the results of a simulation of wind speed in the optical module. Fig. 18 is a diagram showing the results of a simulation of the temperature of the semiconductor laser in the optical module. Fig. 19 is a diagram showing the results of a simulation of the temperature of the semiconductor laser in the optical module. Fig. 20 is a diagram showing the results of a simulation of the temperature of the semiconductor laser in the optical module. Fig. 21 is a diagram showing the results of a simulation of the temperature of the semiconductor laser in the optical module. Fig. 22 is a diagram showing the results of a simulation of the temperature of components inside the optical module. Fig. 23 is a diagram showing the results of a simulation of the temperature of components inside the optical module. Fig. 24 is a diagram showing the results of a simulation of the temperature of components inside the optical module. Fig. 25 is a diagram showing the results of a simulation of the temperature of components inside the optical module. Fig. 26 is a diagram showing the results of a simulation of wind speed in the optical module. Fig. 27 is a diagram showing the results of a simulation of wind speed in the optical module.Fig. 28 is a diagram showing the results of simulating the wind speed in the optical module. Fig. 29 is a diagram showing the results of simulating the wind speed in the optical module.

[0021] Hereinafter, several exemplary embodiments of the present invention will be disclosed. The configurations of the embodiments shown below, as well as the actions and results (effects) brought about by these 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.

[0022] The following embodiments have similar configurations. Therefore, according to the configuration of each embodiment, similar actions and effects based on the similar configurations can be obtained. Furthermore, in the following, similar configurations are given similar reference numerals, and duplicated explanations may be omitted. Furthermore, each drawing is a schematic diagram, and the dimensions in the drawing may differ from the actual dimensions.

[0023] 1 is a schematic diagram of a light source device including an optical module according to an embodiment. As shown in FIG. 1, the light source device 100 includes an optical module 10, a case 20, a cage 30, and an air-cooling fan 40.

[0024] The case 20 houses a switch ASIC (Application Specific Integrated Circuit), a SiPh transceiver, etc. that constitute a CPO (Co-Packaged Optics). A cage 30 is fixed to a front panel 21 of the case 20, and an optical module 10 is inserted into the cage 30. In other words, the case 20 holds the optical module 10 via the cage 30. A cooling fan 40 is attached to the rear of the case 20 to cool the inside of the case 20.

[0025] Fig. 2 is a perspective view of the optical module shown in Fig. 1. Fig. 3 is an exploded view of the optical module. Fig. 4 is a schematic cross-sectional view of the optical module. Fig. 5 is a schematic plan view of the optical module. As shown in Figs. 2 to 5, the optical module 10 includes a housing composed of a lower housing 1 and an upper housing 2, a TOSA (Transmitter Optical Sub-Assembly) 3 as an optical transmitter, a heat dissipation sheet 4, a copper plate 5, a control board 6, a drive circuit 7, a connection section 8, and an optical fiber 9.

[0026] The optical module 10 is inserted into a cage 30 attached to the front panel 21 of the case 20 so that the connection portion 8 is located inside the case 20 .

[0027] The housing has predetermined dimensions and is composed of a lower housing 1 and an upper housing 2 that covers the opening of the lower housing 1. The predetermined dimensions are determined, for example, by a standard. A heat sink 2a including plate-shaped air-cooling fins extending along the longitudinal direction of the housing is provided on the upper surface of the upper housing 2. When the optical module 10 is inserted into the cage 30, the gap surrounded by the upper surface of the upper housing 2, the cage 30, and the air-cooling fins becomes an air vent, and when the air-cooling fan 40 is driven, air passes through from the outside to cool the optical module 10. Note that when the air-cooling fan 40 is driven, air flows from the side opposite the connection portion 8 toward the connection portion 8 (from left to right in FIG. 4 ).

[0028] Furthermore, through holes 1b are formed on both side surfaces of the lower housing 1. However, the through holes only need to be formed on the side surfaces of the housing, and may also be formed on both side surfaces of the upper housing 2. Furthermore, it is preferable that the through holes 1b are formed near the drive circuit 7. Furthermore, it is preferable that the through holes 1b are formed at a position farther away from the connection portion 8 than the drive circuit 7. Furthermore, it is preferable that the through holes 1b are formed outside the case 20 than the drive circuit 7.

[0029] The TOSA 3 is housed in a housing. The TOSA 3 includes multiple semiconductor lasers. For example, the TOSA 3 includes eight semiconductor lasers, but the number of semiconductor lasers is not particularly limited. Heat generated by driving the semiconductor lasers of the TOSA 3 is dissipated from the heat sink 2 a via the heat dissipation sheet 4 and the copper plate 5.

[0030] The control board 6 is, for example, a printed circuit board, and has a drive circuit 7 that drives the TOSA 3 mounted thereon.

[0031] The drive circuit 7 is an electronic component that drives the TOSA 3, and includes electronic components that generate a lot of heat, such as an LDO (Low Drop Out) regulator that reduces voltage, resistors, capacitors, and various processors.

[0032] The connection unit 8 is optically and electrically connected to an external device. Specifically, the connection unit 8 includes an electrical connector provided on the back surface of the control board 6 and an optical connector provided on the top surface of the control board 6.

[0033] The optical fiber 9 is a polarization-maintaining fiber that connects the TOSA 3 and the connection unit 8, and is accommodated in the housing. One end of the optical fiber 9 is connected to the TOSA 3 from the side opposite the connection unit 8, and the other end is connected to an optical connector of the connection unit 8 provided on the top surface of the control board 6. As a result, the optical fiber 9 is routed between the control board 6 and the upper housing 2.

[0034] [Simulation Results in the Case Where No Through-Hole is Present] Next, the results of various simulations performed on the optical module 10 that does not have a through-hole will be described.

[0035] 6 shows the results of a simulation of the wind speed in the optical module. As shown in Fig. 6, by driving the cooling fan 40, air is taken in through the air intake port at the top of the upper housing 2 and passes between the cooling fins of the heat sink 2a, efficiently increasing the wind speed. Furthermore, no air is circulated inside the housing.

[0036] 7 shows the results of a simulation of the temperature in the optical module. As shown in FIG. 7, heat from the TOSA 3 is dissipated to the air-cooling fins of the heat sink 2a, which can prevent the temperature of the semiconductor laser in the TOSA 3 from rising. Furthermore, when driving the semiconductor laser in the TOSA 3, the electronic components of the driver circuit 7 may generate heat, which may increase the temperature of the semiconductor laser.

[0037] 8 shows the results of a simulation of the air temperature in the optical module. As shown in Fig. 8, the air temperature in the housing near the semiconductor laser of the TOSA 3 rises, but the air temperature near the electronic components of the drive circuit 7 is even higher.

[0038] From the above simulation results, it is preferable to suppress the temperature rise of the semiconductor laser due to heat generated by the electronic components of the drive circuit 7. However, because the optical fiber 9 is routed above the drive circuit 7, it is not possible to dissipate heat by placing a heat dissipation sheet or copper plate directly on the top surface of the drive circuit 7. Therefore, in this embodiment, through holes 1b are formed on both side surfaces of the lower housing 1 near the drive circuit 7.

[0039] [Comparison Results Between Cases with and without Through Holes] Next, the results of comparisons between various simulations of optical modules with and without through holes will be described.

[0040] 9 is a plan view of an upper housing of an optical module according to a modified example. Cooling fins of a heat sink 2a are formed on the top surface of an upper housing 2A of the optical module according to the modified example. It is preferable that through-holes 2Ab are formed on the top surface of the upper housing 2A so as to be positioned between the cooling fins of the heat sink 2a. It is also preferable that through-holes 2Ab are formed closer to the connection portion 8 than the TOSA 3.

[0041] FIGS. 10 to 17 show the results of simulating wind speed in an optical module. FIGS. 10 to 13 are side views of the optical module, and FIGS. 14 to 17 are top views of the optical module. FIGS. 10 and 14 show results for a case in which the optical module 10N does not have a through-hole. The lower housing 1N in FIGS. 10 and 14 does not have a through-hole. FIGS. 11 and 15 show results for a case in which the optical module 10A has a through-hole 1b formed on its side surface. FIGS. 12 and 16 show results for a case in which the optical module 10A has a through-hole 2Ab formed on its top surface. FIGS. 13 and 17 show results for a case in which the optical module 10B has a through-hole 1b formed on its side surface and a through-hole 2Ab formed on its top surface.

[0042] Comparing Figures 10 to 13, it can be seen that a change in wind speed occurs near the through holes 1b and 2Ab, and air flows into the housing through the through holes 1b and 2Ab and is discharged outside the housing (inside the case 20).

[0043] 14 to 17, it can be seen that the formation of the through holes 1b and 2Ab does not reduce the speed of the air passing between the cooling fins of the heat sink 2a.

[0044] 18 to 21 are diagrams showing the results of simulating the temperature of a semiconductor laser in an optical module. 18 to 21 are side views of the optical module. 18 shows the results when the optical module 10N does not have a through-hole. 19 shows the results when the optical module 10 has a through-hole 1b. 20 shows the results when the optical module 10A has a through-hole 2Ab formed on its top surface. 21 shows the results when the optical module 10B has a through-hole 1b formed on its side surface and a through-hole 2Ab formed on its top surface.

[0045] 18 to 21, the temperature of the semiconductor laser was reduced from 55.7°C when there were no through holes to 53.1°C by forming through holes 1b on the side surfaces, 52.4°C by forming through holes 2Ab on the top surface, and 51.9°C by forming through holes 1b and 2Ab on the side surfaces and top surface. Furthermore, the temperature of the drive circuit 7 was reduced from 65.6°C when there were no through holes to 63.8°C by forming through holes 1b on the side surfaces, 61.2°C by forming through holes 2Ab on the top surface, and 60.5°C by forming through holes 1b and 2Ab on the side surfaces and top surface.

[0046] 22 to 25 are diagrams showing the results of simulating the temperatures of components inside the optical module. FIG. 22 shows the results when the optical module 10N does not have a through-hole. FIG. 23 shows the results when the optical module 10 has a through-hole 1b. FIG. 24 shows the results when the optical module 10A has a through-hole 2Ab formed on the top surface. FIG. 25 shows the results when the optical module 10B has a through-hole 1b formed on the side surface and a through-hole 2Ab formed on the top surface.

[0047] A comparison of FIGS. 22 to 25 reveals that the formation of the through-hole 1b or 2Ab significantly reduces the temperature in the vicinity of the semiconductor laser.

[0048] 26 to 29 are diagrams showing the results of simulating wind speed in optical modules. FIG. 26 shows the results when the optical module 10N does not have a through-hole. FIG. 27 shows the results when the optical module 10 has a through-hole 1b. FIG. 28 shows the results when the optical module 10A has a through-hole 2Ab formed on the top surface. FIG. 29 shows the results when the optical module 10B has a through-hole 1b formed on the side surface and a through-hole 2Ab formed on the top surface.

[0049] In the optical module 10N shown in Fig. 26 without through holes, the air velocity is maximized at the end of the air-cooling fins, which do not contribute to cooling, and cooling is not effective. On the other hand, in the optical module 10A shown in Fig. 28 with through holes 2Ab formed on the top surface, when the through holes 2Ab are provided in front of the TOSA 3 (on the connection portion 8 side), the air velocity increases in the part of the air-cooling fin located directly above the TOSA 3 compared to when there are no through holes, and the TOSA 3 is cooled effectively. Furthermore, in the optical module 10A, convection from the inside of the housing, where the temperature is high, to the outside occurs due to the chimney effect, so the temperature of the heat-generating internal components can also be cooled effectively.

[0050] The through-holes 2Ab on the top surface are preferably positioned near the TOSA 3 and closer to the connection portion 8 than the TOSA 3. This is because forming the through-holes directly above the TOSA 3 prevents air convection inside the housing, making it difficult to achieve a cooling effect. The through-holes 2Ab on the top surface are also preferably positioned between the air-cooling fins. This is because the air speed passing between the air-cooling fins increases, enabling effective cooling. Furthermore, with this configuration, the air-cooling fins are not interrupted at the top of the housing, allowing the air flow over the air-cooling fins to be guided from the case 20 side to the connection portion 8 side. On the other hand, if the air-cooling fins are interrupted at the top of the housing, the air flows in the width direction of the housing, making cooling ineffective.

[0051] According to the embodiment described above, the through-hole 1b is formed in the lower housing 1, so that outside air flows into the housing, and the temperature rise inside the housing of the optical module 10 can be suppressed.

[0052] Furthermore, according to the embodiment, the through hole 1b is formed in the vicinity of the drive circuit 7. As a result, the temperature in the vicinity of the drive circuit 7 can be reduced, which is highly effective in suppressing a temperature rise inside the housing of the optical module 10.

[0053] Furthermore, according to the embodiment, the through hole 1b is formed at a position farther away from the connection portion 8 than the drive circuit 7. As a result, the air flowing in from the through hole 1b toward the connection portion 8 reduces the temperature near the drive circuit 7, which is highly effective in suppressing a temperature rise inside the housing of the optical module 10.

[0054] Furthermore, according to the embodiment, the optical fiber 9 is housed in the housing and routed between the control board 6 and the upper housing 2, so although it is not possible to dissipate heat by placing a heat dissipation sheet or copper plate directly on the top surface of the drive circuit 7, the through hole 1b can reduce the temperature near the drive circuit 7, thereby suppressing the temperature rise inside the housing of the optical module 10.

[0055] Furthermore, according to the embodiment, the through hole 1b is formed outside the case 20 relative to the drive circuit 7. As a result, the air flowing in from the through hole 1b toward the connection portion 8 reduces the temperature near the drive circuit 7, which is highly effective in suppressing a temperature rise inside the housing of the optical module 10.

[0056] The number, shape, and size of the through holes are not particularly limited, and may be, for example, three or more. Furthermore, the through holes 1b are not limited to being formed on the side surface of the upper housing 2, and may be formed in any part of the housing, for example, directly below the air-cooling fins.

[0057] Furthermore, in the above-described embodiment, an example has been described in which air-cooling fins are provided on the top surface of the upper housing 2, but air-cooling fins may also be provided on the top surface of the cage 30. Specifically, plate-shaped air-cooling fins extending along the longitudinal direction of the upper housing 2 are provided on the top surface of the cage 30. In this case, the upper housing 2 does not necessarily have to be provided with air-cooling fins, but it is preferable to use a structure in which heat generated by driving the semiconductor laser of the TOSA 3 is dissipated from the air-cooling fins of the cage 30 via the heat dissipation sheet 4, the copper plate 5, and the upper housing 2. Furthermore, it is preferable that a through hole is formed in the cage 30 at a position overlapping with the through hole 1b of the lower housing 1.

[0058] While the above describes exemplary embodiments of the present invention, the above embodiments 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 appropriately modified and implemented.

[0059] REFERENCE SIGNS LIST 1, 1N Lower housing 2, 2A Upper housing 1b, 2Ab Through-hole 2a Heat sink 3 TOSA 4 Heat dissipation sheet 5 Copper plate 6 Control board 7 Drive circuit 8 Connection part 9 Optical fiber 10, 10A, 10B, 10N Optical module 20 Case 21 Front panel 30 Cage 40 Cooling fan 100 Light source device

Claims

1. An optical module comprising: a housing having a through hole; an optical transmitter housed in said housing; a control board on which a drive circuit for driving said optical transmitter is mounted; a connection part optically and electrically connected to an external device; and an optical fiber connecting said optical transmitter and said connection part.

2. The optical module according to claim 1, wherein the housing is composed of a lower housing and an upper housing that covers the opening of the lower housing.

3. The optical module according to claim 1, wherein the through-hole is formed in the top surface or side surface of the housing.

4. The optical module according to claim 1, wherein the through hole is formed in the vicinity of the drive circuit.

5. The optical module according to claim 1, wherein the through hole is formed in the upper surface of the housing and is formed closer to the connection section than the optical transmitter section.

6. The optical module according to claim 1, wherein a plate-shaped air-cooling fin extending along the longitudinal direction of said housing is provided on the upper surface of said housing.

7. The optical module according to claim 6, wherein the through hole is formed at a position farther away from the connection portion than the drive circuit.

8. The optical module according to claim 6, wherein the through-hole is formed on the top surface of the housing so as to be positioned between the cooling fins.

9. The optical module according to claim 1, wherein the optical fiber is accommodated in the housing.

10. The optical module according to claim 2, wherein the optical fiber is routed between the control board and the upper housing.

11. A light source device comprising: an optical module according to claim 1; a case for holding the optical module so that the connection portion is located inside; and air-cooling fins attached to the case, wherein the through-hole is formed outside the case relative to the drive circuit.

12. The light source device according to claim 11, further comprising a cage fixed to the case and holding the optical module, the upper surface of the cage being provided with plate-shaped air-cooling fins extending along the longitudinal direction of the housing.

13. The light source device according to claim 12, wherein the cage has a through-hole formed in a position that overlaps with the through-hole of the housing.

Images