Optical module

Abstract

An optical module (10) includes, for example: a housing (1) of a prescribed dimension; a first optical transmitting unit (2) and a second optical transmitting unit (3) which are accommodated in the housing (1); a control board (4) on which a drive circuit for driving the first optical transmitting unit (2) and the second optical transmitting unit (3) is mounted; a connection unit (6) which optically and electrically connects to an external device; a first optical fiber (7) which connects the first optical transmitting unit (2) and the connection unit (6); and a second optical fiber (8) which connects the second optical transmitting unit (3) and the connection unit (6).　Thus, for example, an optical module is provided in which two transmitter optical sub-assemblies (TOSA) are mounted within a housing of a prescribed dimension.

Description

Optical Module

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

[0002] An optical module equipped with a TOSA (Transmitter Optical Sub-Assembly) has been disclosed (see, for example, Patent Document 1).

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

[0004] There is a demand for a device that incorporates a multi-channel TOSA having multiple semiconductor lasers within a housing of a predetermined size, and there is also a demand for a device that incorporates two TOSAs within a housing of a predetermined size.

[0005] Therefore, one of the objects of the present invention is to provide an optical module in which, for example, two TOSAs are mounted in a housing of a predetermined size.

[0006] The optical module of the present invention comprises, for example, a housing of a predetermined dimension, a first optical transmitting unit and a second optical transmitting unit housed in the housing, a control board on which a drive circuit for driving the first optical transmitting unit and the second optical transmitting unit is mounted, a connection unit optically and electrically connected to an external device, a first optical fiber connecting the first optical transmitting unit and the connection unit, and a second optical fiber connecting the second optical transmitting unit and the connection unit.

[0007] In the optical module, the first optical transmitter and the second optical transmitter may be arranged side by side along a longitudinal direction of the housing.

[0008] In the optical module, the first optical transmitter and the second optical transmitter each may include eight semiconductor lasers, and the semiconductor lasers may be spaced apart by 1.2 mm or more.

[0009] In the optical module, the control board may be arranged on the underside of the housing, and the first optical transmitter and the second optical transmitter may be arranged on the upper side of the housing at a distance from the control board.

[0010] In the optical module, a heat sink may be arranged on the top of the housing, and the first optical transmitter and the second optical transmitter may be arranged so as to be in thermal contact with the heat sink via the upper surface of the housing.

[0011] In the optical module, at least one of an LDO (Low Drop Out) regulator, a processor, an MCU (Micro Controller Unit), an FET (Field Effect Transistor), and a DCDC converter among the electronic components constituting the drive circuit may be disposed between the first optical transmitter and the second optical transmitter.

[0012] In the optical module, the first optical fiber and the second optical fiber may have a length of 50 mm or more.

[0013] In the optical module, the first optical fiber and the second optical fiber may have a curved portion that is curved 180 degrees within the housing.

[0014] In the optical module, the first optical fiber and the second optical fiber may each have two or more curved portions.

[0015] According to the present invention, for example, an optical module can be obtained in which two TOSAs are mounted in a housing of a predetermined size.

[0016] FIG. 1 is a schematic diagram of a light source device including an optical module according to an embodiment. FIG. 2 is an exploded perspective view of an optical module, a cage, and a connector. FIG. 3 is a schematic diagram of the optical module. FIG. 4 is a schematic cross-sectional view of the optical module. FIG. 5 is a diagram showing heat distribution when the spacing between semiconductor lasers in a TOSA is changed. FIG. 6 is a diagram showing temperatures of semiconductor lasers and a case when the spacing between semiconductor lasers in a TOSA is changed. FIG. 7 is a diagram showing the results of a thermal simulation of an optical module. FIG. 8 is a schematic diagram of an optical module according to a first modification. FIG. 9 is a schematic diagram of an optical module according to a second modification.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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. A cooling fan 40 is attached to the rear of the case 20 to cool the inside of the case 20.

[0021] 2 is an exploded perspective view of the optical module, cage, and connector. As shown in Fig. 2, the optical module 10 is inserted into the cage 30 fixed to the front panel 21 of the case 20, and a connector 60 is connected from inside the case 20. As a result, the optical module 10 is optically and electrically connected to each component provided in the light source device 100. A heat sink 50 may also be provided on top of the cage 30. The heat sink 50 has, for example, a plurality of plate-shaped heat dissipation fins extending along the longitudinal direction of the optical module 10.

[0022] Fig. 3 is a schematic configuration diagram of the optical module. Fig. 4 is a schematic cross-sectional view of the optical module. As shown in Figs. 3 and 4, the optical module 10 includes a housing 1, a TOSA (Transmitter Optical Sub-Assembly) 2 as a first optical transmitter, a TOSA 3 as a second optical transmitter, a control board 4, electronic components 5, a connection unit 6, an optical fiber 7 as a first optical fiber, and an optical fiber 8 as a second optical fiber.

[0023] The housing 1 has a predetermined size and accommodates the TOSAs 2 and 3. The predetermined size is determined by, for example, a standard.

[0024] TOSAs 2 and 3 are arranged side by side along the longitudinal direction of the housing 1. Preferably, TOSAs 2 and 3 are arranged on the upper surface of the housing 1 at a distance from the control board 4. To enhance heat dissipation, TOSAs 2 and 3 are preferably arranged so as to be in thermal contact with a heat sink via the upper surface of the housing 1. TOSAs 2 and 3 are bonded to the upper surface of the housing 1, for example, with a thermally conductive sheet having high thermal conductivity, but may also be bonded with various adhesives. The heat sink need only be arranged so as to be in thermal contact with TOSAs 2 and 3, and may be provided on the upper surface of the housing 1 or on the upper surface of the cage 30.

[0025] Figure 5 shows the heat distribution when the spacing between the semiconductor lasers in the TOSA is changed. As shown in Figure 5, TOSAs 2 and 3 are multi-channel TOSAs each containing eight semiconductor lasers. That is, the optical module 10 is equipped with 16 semiconductor lasers (16 channels). The distance LP between the semiconductor lasers was changed in increments of 0.4 mm, and the heat distribution when the semiconductor lasers were driven was simulated. Figure 5 shows examples where the distance LP was 0.4, 0.8, and 1.2 mm.

[0026] 6 is a diagram showing the temperature of the semiconductor laser and the case when the distance between the semiconductor lasers in the TOSA is changed. As shown in FIG. 6, the temperature TC of the case 20 was set to 55°C. When the distance LP between the semiconductor lasers is changed, the temperature TL of the semiconductor laser decreases when the distance LP is 1.2 mm or more. From this result, in order to lower the temperature TL of each semiconductor laser, it is preferable to arrange the semiconductor lasers at a distance of 1.2 mm or more.

[0027] 7 shows the results of a thermal simulation of the optical module. As shown in FIG. 7, the results of a thermal simulation of the optical module 10 show that it is preferable to space TOSA 2 and TOSA 3 apart by 19 mm or more. Heat generated from TOSA 2 and TOSA 3 is dissipated through the top surface of the housing 1 and from a heat sink provided in the cage 30.

[0028] The control board 4 is, for example, a printed circuit board, and has mounted thereon a drive circuit that drives the TOSAs 2 and 3. The control board 4 is disposed on the lower surface side of the housing 1.

[0029] The electronic component 5 includes at least one of the following electronic components constituting the drive circuit: an LDO (Low Drop Out) regulator that reduces voltage, a processor, an MCU (Micro Controller Unit), an FET (Field Effect Transistor), and a DCDC converter. The electronic component 5 is preferably disposed between the TOSA 2 and the TOSA 3 in the longitudinal direction of the optical module 10.

[0030] The connection portion 6 is optically and electrically connected to an external device and includes two MT (Mechanically Transferable) ferrules, each of which is connected to the TOSA2 and the TOSA3.

[0031] The optical fiber 7 is a polarization-maintaining fiber that connects the TOSA 2 and the MT ferrule of the connection unit 6. The optical fiber 8 is a polarization-maintaining fiber that connects the TOSA 3 and the MT ferrule of the connection unit 6. When connecting the optical fibers 7 and 8 to the MT ferrule of the connection unit 6, it is necessary to rotate and align the polarization-maintaining fibers of the optical fibers 7 and 8. In order to reduce stress caused by the polarization-maintaining fibers during alignment, the lengths of the optical fibers 7 and 8 are preferably 50 mm or more.

[0032] 3, the optical fiber 7 is connected upward from the TOSA 2, extends toward the upper end, and is bent 180 degrees at the upper end. In other words, the optical fiber 7 has a curved portion that is bent 180 degrees within the housing 1. Because the optical fiber 7 extends toward the end connected to the TOSA 2, the optical fiber 7 can be routed so that the curvature of the optical fiber 7 is small near the connection portion with the TOSA 2, thereby reducing bending loss.

[0033] Similarly, the optical fiber 8 is connected downward from the TOSA 3, extends toward the lower end, is bent 180 degrees at the lower end, and is further bent 180 degrees at the upper end. In other words, the optical fiber 7 has two 180-degree bends within the housing 1. Because the optical fiber 8 extends toward the end connected to the TOSA 3, the optical fiber 8 can be routed so that the curvature of the optical fiber 8 is small near the connection with the TOSA 3, thereby reducing bending loss.

[0034] Furthermore, if the distance between TOSA2 and TOSA3 becomes small, the stress on the optical fibers 7 and 8 increases, leading to the occurrence of bending loss and deterioration of the polarization extinction ratio. Therefore, it is preferable that TOSA2 and TOSA3 are spaced apart by 19 mm or more.

[0035] According to the embodiment described above, an optical module 10 can be realized in which the TOSAs 2 and 3 are mounted in a housing 1 of a predetermined size.

[0036] Furthermore, according to the embodiment, the TOSAs 2 and 3 are arranged side by side along the longitudinal direction of the housing 1, so that even if the housing 1 has an elongated shape, two TOSAs can be mounted thereon.

[0037] Furthermore, according to the embodiment, the semiconductor lasers are arranged at intervals of 1.2 mm or more, so that the optical module 10 has good heat dissipation performance.

[0038] In the past, the number of channels was limited to around four, and the housing dimensions were large, so it was possible to arrange multiple semiconductor lasers side by side in the width direction of the housing. However, as the number of channels increases and the housing becomes smaller, it becomes difficult to arrange the semiconductor lasers within the housing while reducing the thermal influence between them.

[0039] In the case of a multi-channel optical module, it is preferable that the semiconductor lasers are spaced apart by 1.2 mm or more to lower the temperature of each semiconductor laser and reduce the influence of the temperature of each semiconductor laser. Arranging multiple semiconductor lasers side by side in the width direction of the housing may not be possible in a housing of the specified dimensions specified by the standard. For example, in the case of a 16-channel optical module, if the semiconductor lasers are spaced apart by 1.2 mm or more and arranged side by side in the width direction of the housing, a minimum of 18 mm is required, which may not be possible depending on the housing dimensions.

[0040] In contrast, according to the embodiment, TOSAs 2 and 3 are arranged side by side along the longitudinal direction of housing 1, so that the semiconductor lasers are spaced apart by 1.2 mm or more and can be accommodated in a housing 1 of a specified dimension.

[0041] Furthermore, according to the embodiment, since the TOSAs 2 and 3 are spaced apart from the control board 4, the area on the control board 4 for mounting electronic components can be made larger.

[0042] Furthermore, according to the embodiment, the TOSAs 2 and 3 are arranged so as to be in thermal contact with the heat sink via the upper surface of the housing 1, so that the optical module 10 can have good heat dissipation performance.

[0043] Furthermore, according to the embodiment, since the electronic component 5 is disposed between the TOSA 2 and the TOSA 3, the influence of heat from the electronic component 5 on the TOSA 2 or the TOSA 3 can be reduced.

[0044] Furthermore, according to the embodiment, the TOSA 2 and the TOSA 3 are spaced apart by 19 mm or more, so that the optical module 10 has good heat dissipation performance.

[0045] Furthermore, according to the embodiment, the length of the optical fibers 7 and 8 is 50 mm or more, so that the stress when rotationally aligning the polarization-maintaining fibers of the optical fibers 7 and 8 can be reduced.

[0046] Furthermore, according to the embodiment, the optical fibers 7 and 8 have one, and more preferably two, curved portions that are bent 180 degrees within the housing, so that an optical fiber having a length of 50 mm or more can be accommodated within the housing 1, and even if there is variation in the length of the optical fiber, it is easy to accommodate the optical fiber within the housing 1.

[0047] (Variation 1) Fig. 8 is a schematic diagram of an optical module according to Variation 1. As shown in Fig. 8, an optical module 10A includes optical fibers 7Aa and 7Ab and optical fibers 8Aa and 8Ab. The optical fibers 7Aa and 8Aa extend leftward from the semiconductor laser disposed on the right side of Fig. 8. Similarly, the optical fibers 7Ab and 8Ab extend curvedly from the semiconductor laser disposed on the left side of Fig. 8 toward the right side. As a result, the optical fibers can be routed so that the curvature of the optical fibers 7Aa, 7Ab, 8Aa, and 8Ab is small near the connection portions with the TOSAs 2 and 3, thereby reducing bending loss.

[0048] As in the embodiment, the optical fibers 7Aa and 7Ab and the optical fibers 8Aa and 8Ab may have curved portions at the lower and upper ends of the optical module 10A. By having two or more curved portions, an optical fiber having a length of 50 mm or more can be accommodated in the housing 1, and even if the optical fibers vary in length, the optical fibers can be easily accommodated in the housing 1.

[0049] (Variation 2) Fig. 9 is a schematic diagram of an optical module according to Variation 2. As shown in Fig. 9, an optical module 10B includes optical fibers 7Ba and 7Bb and optical fibers 8Ba and 8Bb. The optical fibers 7Ba and 8Ba extend in a curved manner from the semiconductor laser disposed on the right side of Fig. 9 toward the left. Similarly, the optical fibers 7Bb and 8Bb extend from the semiconductor laser disposed on the left side of Fig. 9 toward the right. As a result, the optical fibers can be routed so that the curvature of the optical fibers 7Ba, 7Bb, 8Ba, and 8Bb is small near the connection portions with the TOSAs 2 and 3, thereby reducing bending loss.

[0050] As in the embodiment, the optical fibers 7Ba and 7Bb and the optical fibers 8Ba and 8Bb may have curved portions at the lower and upper ends of the optical module 10B. By having two or more curved portions, an optical fiber having a length of 50 mm or more can be accommodated in the housing 1, and even if the optical fibers vary in length, the optical fibers can be easily accommodated in the housing 1.

[0051] 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.

[0052] REFERENCE SIGNS LIST 1 Housing 2, 3 TOSA 4 Control board 5 Electronic components 6 Connection section 7, 7Aa, 7Ab, 7Ba, 7Bb, 8, 8Aa, 8Ab, 8Ba, 8Bb Optical fiber 10, 10A, 10B Optical module 20 Case 21 Front panel 30 Cage 40 Cooling fan 50 Heat sink 60 Connector 100 Light source device

Claims

1. An optical module comprising: a housing of a predetermined size; a first optical transmitter and a second optical transmitter housed in the housing; a control board on which a drive circuit for driving the first optical transmitter and the second optical transmitter is mounted; a connection section optically and electrically connected to an external device; a first optical fiber connecting the first optical transmitter and the connection section; and a second optical fiber connecting the second optical transmitter and the connection section.

2. The optical module according to claim 1, wherein the first optical transmitter and the second optical transmitter are arranged side by side along the longitudinal direction of the housing.

3. An optical module according to claim 1, wherein the first optical transmitter and the second optical transmitter each include eight semiconductor lasers, and the semiconductor lasers are spaced apart by 1.2 mm or more.

4. An optical module as described in claim 1, wherein the control board is arranged on the underside of the housing, and the first optical transmitter and the second optical transmitter are arranged on the upper side of the housing at a distance from the control board.

5. An optical module as described in claim 1, wherein a heat sink is disposed on the upper part of the housing, and the first optical transmitter and the second optical transmitter are disposed so as to be in thermal contact with the heat sink via the upper surface of the housing.

6. The optical module according to claim 1, wherein at least one of the electronic components constituting the drive circuit, an LDO (Low Drop Out) regulator, a processor, an MCU (Micro Controller Unit), an FET (Field Effect Transistor), and a DCDC converter, is disposed between the first optical transmitter and the second optical transmitter.

7. The optical module according to claim 1, wherein the lengths of the first optical fiber and the second optical fiber are 50 mm or more.

8. The optical module according to claim 1, wherein the first optical fiber and the second optical fiber have a curved portion that is bent 180 degrees within the housing.

9. The optical module according to claim 8, wherein the first optical fiber and the second optical fiber have two or more curved portions.

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