WO2025205469A1 - Optical module - Google Patents

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

The present invention relates to an optical module.

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

Japanese Patent Application Laid-Open No. 2020-98249

However, there is a demand for devices equipped with a multi-channel TOSA having multiple semiconductor lasers within a housing of specified dimensions. Furthermore, there is a demand for devices equipped with two TOSAs within a housing of specified dimensions.

Therefore, one of the objectives of the present invention is to obtain an optical module that incorporates, for example, two TOSAs within a housing of specified dimensions.

The optical module of the present invention comprises, for example, a housing of predetermined dimensions, 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.

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

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

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.

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

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

In the optical module, the length of the first optical fiber and the second optical fiber may be 50 mm or more.

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

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

According to the present invention, for example, an optical module can be obtained that incorporates two TOSAs within a housing of specified dimensions.

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 the optical module, the cage, and the 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 the heat distribution when the interval between the semiconductor lasers in the TOSA is changed. FIG. 6 is a diagram showing the temperatures of the semiconductor laser and the case when the interval between the semiconductor lasers in the TOSA is changed. FIG. 7 shows the results of a thermal simulation of an optical module. FIG. 8 is a schematic diagram of an optical module according to the first modification. FIG. 9 is a schematic diagram of an optical module according to the second modification.

Below, several exemplary embodiments of the present invention are disclosed. The configurations of the embodiments shown below, as well as the actions and results (effects) brought about by said configurations, are merely examples. The present invention can also be realized with 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.

The multiple embodiments shown below have similar configurations. Therefore, according to the configuration of each embodiment, similar actions and effects based on the similar configurations can be obtained. Furthermore, below, similar configurations will be assigned similar reference numerals, and duplicate explanations may be omitted. Furthermore, each figure is schematic, and the dimensions in the figures may differ from the actual dimensions.

[Embodiment]
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.

The case 20 houses components that make up the CPO (Co-Packaged Optics), such as a switch ASIC (Application Specific Integrated Circuit) and a SiPh transceiver. A cage 30 is fixed to the 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 back of the case 20 to cool the interior of the case 20.

Figure 2 is an exploded perspective view of the optical module, cage, and connector. As shown in Figure 2, the optical module 10 is inserted into the cage 30 fixed to the front panel 21 of the case 20, and the 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 within 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, multiple plate-shaped heat dissipation fins extending along the longitudinal direction of the optical module 10.

Figure 3 is a schematic diagram of the optical module. Figure 4 is a schematic cross-sectional view of the optical module. As shown in Figures 3 and 4, the optical module 10 comprises 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.

Housing 1 has predetermined dimensions and accommodates TOSAs 2 and 3. The predetermined dimensions are determined, for example, by standards.

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 top surface of the housing 1 at a distance from the control board 4. To improve heat dissipation, TOSAs 2 and 3 are preferably arranged so that they are in thermal contact with the heat sink via the top surface of the housing 1. TOSAs 2 and 3 are adhered to the top surface of the housing 1, for example, with a thermally conductive sheet having high thermal conductivity, but they may also be adhered with various adhesives. The heat sink only needs to be arranged so that it is in thermal contact with TOSAs 2 and 3, and may be arranged on the top surface of the housing 1 or on the top surface of the cage 30.

Figure 5 shows the heat distribution when the spacing between semiconductor lasers in a TOSA is changed. As shown in Figure 5, TOSA2 and 3 are multi-channel TOSAs each containing eight semiconductor lasers. In other words, 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 is 0.4, 0.8, and 1.2 mm.

Figure 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 Figure 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.

Figure 7 shows the results of a thermal simulation of the optical module. As shown in Figure 7, the results of a thermal simulation of the optical module 10 show that it is preferable to position TOSA2 and TOSA3 at a distance of 19 mm or more. Heat generated by TOSA2 and TOSA3 is dissipated via the top surface of the housing 1 to a heat sink provided in the cage 30.

The control board 4 is, for example, a printed circuit board, and is equipped with a drive circuit that drives the TOSAs 2 and 3. The control board 4 is located on the underside of the housing 1.

Electronic component 5 includes at least one of the following electronic components that make up the drive circuit: an LDO (Low Drop Out) regulator that reduces voltage, a processor, an MCU (Micro Controller Unit), an FET (Field Effect Transistor), or a DCDC converter. Electronic component 5 is preferably arranged between TOSA2 and TOSA3 in the longitudinal direction of optical module 10.

Connection section 6 is optically and electrically connected to an external device. Connection section 6 includes two MT (Mechanically Transferable) ferrules, each of which is connected to TOSA2 and TOSA3, respectively.

Optical fiber 7 is a polarization-maintaining fiber that connects TOSA 2 to the MT ferrule of connection portion 6. Optical fiber 8 is a polarization-maintaining fiber that connects TOSA 3 to the MT ferrule of connection portion 6. When connecting optical fibers 7 and 8 to the MT ferrule of connection portion 6, it is necessary to rotate and align the polarization-maintaining fibers of optical fibers 7 and 8. To reduce the stress caused by the polarization-maintaining fibers during alignment, it is preferable that the length of optical fibers 7 and 8 be 50 mm or more.

Also, as shown in Figure 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 bends 180 degrees within the housing 1. Because the optical fiber 7 extends toward the end in the direction 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 point with the TOSA 2, thereby reducing bending loss.

Similarly, the optical fiber 8 is connected downward from the TOSA 3, extends toward the lower end, and is bent 180 degrees at the lower end and again 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, it 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.

Furthermore, if the distance between TOSA2 and TOSA3 becomes too small, the stress on optical fibers 7 and 8 will increase, leading to bending loss and a deterioration in the polarization extinction ratio. Therefore, it is preferable that TOSA2 and TOSA3 be spaced at least 19 mm apart.

The embodiment described above makes it possible to realize an optical module 10 equipped with TOSAs 2 and 3 within a housing 1 of specified dimensions.

Furthermore, according to the embodiment, TOSAs 2 and 3 are arranged side by side along the longitudinal direction of the housing 1, so two TOSAs can be installed even if the housing 1 has a long and narrow shape.

Furthermore, according to the embodiment, the semiconductor lasers are arranged at least 1.2 mm apart from one another, resulting in an optical module 10 with excellent heat dissipation performance.

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.

In the case of a multi-channel optical module, it is preferable that the semiconductor lasers are spaced at least 1.2 mm apart to keep the temperature of each semiconductor laser low and reduce the impact of the temperature of each semiconductor laser. When attempting to line up multiple semiconductor lasers across the width of the housing, they may not be able to fit into a housing of the specified dimensions prescribed by the standard. For example, in the case of a 16-channel module, lining up the semiconductor lasers across the width of the housing with a distance of 1.2 mm or more between each semiconductor laser requires a minimum of 18 mm, which may not be possible depending on the housing dimensions.

In contrast, according to the embodiment, TOSAs 2 and 3 are arranged side by side along the longitudinal direction of the housing 1, so the semiconductor lasers are spaced at least 1.2 mm apart from each other and can be housed in a housing 1 of specified dimensions.

Furthermore, according to the embodiment, TOSAs 2 and 3 are spaced apart from the control board 4, allowing for a larger area on the control board 4 for mounting electronic components.

Furthermore, according to the embodiment, TOSAs 2 and 3 are arranged so that they are in thermal contact with the heat sink via the top surface of the housing 1, thereby achieving an optical module 10 with excellent heat dissipation performance.

Furthermore, according to the embodiment, since the electronic component 5 is disposed between TOSA2 and TOSA3, the thermal influence from the electronic component 5 on TOSA2 or TOSA3 can be reduced.

Furthermore, according to the embodiment, TOSA2 and TOSA3 are spaced apart by 19 mm or more, resulting in an optical module 10 with excellent heat dissipation performance.

Furthermore, according to the embodiment, the length of optical fibers 7 and 8 is 50 mm or more, which reduces the stress that occurs when rotating and aligning the polarization-maintaining fibers of optical fibers 7 and 8.

Furthermore, according to the embodiment, optical fibers 7 and 8 have one, and more preferably two, curved portions that bend 180 degrees within the housing, making it possible to accommodate optical fibers with lengths of 50 mm or more within the housing 1, and it is easy to accommodate optical fibers within the housing 1 even if the optical fibers vary in length.

(Variation 1)
Fig. 8 is a schematic diagram of an optical module according to Modification 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.

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

(Variation 2)
Fig. 9 is a schematic diagram of an optical module according to Modification 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.

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

The above describes exemplary embodiments of the present invention, but the above embodiments are merely examples and are not intended to limit the scope of the invention. The above embodiments can be implemented in a variety of 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.

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 (9)

a housing of predetermined dimensions;
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 that is optically and electrically connected to an external device;
a first optical fiber connecting the first optical transmitter and the connection unit;
a second optical fiber connecting the second optical transmitter and the connection unit;
An optical module comprising: The optical module described in claim 1, wherein the first optical transmitter and the second optical transmitter are arranged side by side along the longitudinal direction of the housing. the first optical transmitting unit and the second optical transmitting unit each include eight semiconductor lasers;
2. The optical module according to claim 1, wherein the semiconductor lasers are spaced apart from one another by 1.2 mm or more. the control board is disposed on the lower surface side of the housing,
The optical module according to claim 1 , wherein the first optical transmitter and the second optical transmitter are arranged on an upper surface of the housing at a distance from the control board. A heat sink is disposed on the upper portion of the housing,
The optical module according to claim 1 , wherein the first optical transmitter and the second optical transmitter are arranged so as to be in thermal contact with the heat sink via an upper surface of the housing. The optical module of 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), or a DCDC converter, is disposed between the first optical transmitter and the second optical transmitter. The optical module described in claim 1, wherein the lengths of the first optical fiber and the second optical fiber are 50 mm or more. The optical module described in claim 1, wherein the first optical fiber and the second optical fiber have curved portions that are bent 180 degrees within the housing. The optical module described in claim 8, wherein the first optical fiber and the second optical fiber have two or more curved portions.