Optical Module

Abstract

To make a heat spreader have an appropriate thickness that comes into contact with each of a plurality elements becoming heat generators.SOLUTION: An optical module includes: a first heat spreader having a first surface; a second heat spreader having a second surface smaller in area than the first surface and attached to the first heat spreader with the second surface in contact with the first surface; an optical processing circuit which is attached to the first heat spreader at a portion of the first surface not in contact with the second surface, and processes and outputs light; and an optical amplifier which is attached to the second heat spreader at the surface opposite the second surface, and amplifies and outputs the light output from the optical processing circuit.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] An example of an optical module is a laser unit configured by combining a SiP (Silicon Photonics) element with an SOA (Semiconductor Optical Amplifier) ​​and a BOA (Booster Optical Amplifier). In the laser unit described above, the SiP element, SOA, and BOA are heat generating elements, and temperature control is required.

[0003] Here, in order to cool a heat generating element with lower power consumption in a TEC (Thermo Electric Cooler), it is effective to increase the heat absorption efficiency of the TEC. Furthermore, in order to increase the heat absorption efficiency of the TEC, it is effective to use a structure that uses a heat spreader to evenly diffuse the heat from the heat-generating body throughout the TEC. A heat dissipation mechanism using a heat spreader is disclosed in, for example, Patent Document 1.

[0004] Therefore, in the laser unit described above, the SiP element, SOA, and BOA are attached in contact with a heat spreader, and the heat from the SiP element, SOA, and BOA is diffused by the heat spreader. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-145536 Summary of the Invention [Problem to be solved by the invention]

[0006] In the above-described laser unit, in order to form the SiP element at low cost, it is effective to reduce the degree of freedom in the thickness of the heat spreader in contact with the SiP element, for example, to set the thickness to a constant value.

[0007] Furthermore, considering the structural aspects of the laser unit described above, it would be effective to use the same heat spreader for the SiP device, the SOA, and the BOA. However, with this structure, even though the SOA and BOA generate more heat than the SiP device, the thickness of the heat spreader in contact with the SOA and BOA is the same as the heat spreader in contact with the SiP device. Therefore, with the above structure, there is a problem in that the heat from the SOA and BOA cannot be sufficiently diffused.

[0008] The above-mentioned problem will be explained below with reference to Figure 1, using the BOA as an example of an SOA or a BOA. The upper diagram in Figure 1 shows a graph that shows the relationship between the thickness of the heat spreader in contact with the BOA, the bottom heat dissipation width, and the total temperature rise. The lower diagram in Figure 1 shows the heat diffusion behavior of the BOA when the thickness of the heat spreader in contact with the BOA is approximately 200 μm and approximately 600 μm, respectively.

[0009] As shown in Figure 1, when the thickness of the heat spreader in contact with the BOA is approximately 200 μm, the bottom heat dissipation width cannot be secured sufficiently. As a result, the heat spreader in contact with the BOA does not dissipate heat sufficiently, and the heat absorption efficiency of the TEC deteriorates. However, the temperature rise of the heat spreader in contact with the BOA is still accommodated.

[0010] On the other hand, if the thickness of the heat spreader in contact with the BOA is approximately 600 μm, the bottom heat dissipation width can be secured sufficiently. Therefore, the heat spreader in contact with the BOA has sufficient heat diffusion, and the heat absorption efficiency of the TEC is high. In addition, the temperature rise of the heat spreader in contact with the BOA can be accommodated.

[0011] Therefore, if the thickness of the heat spreader in contact with the SiP element is constant at approximately 200 μm, and the thickness of the heat spreader in contact with the BOA is the same as that of the heat spreader in contact with the SiP element, the heat from the BOA cannot be sufficiently diffused.

[0012] For this reason, the thickness of the heat spreader in contact with the BOA must be thicker than the thickness of the heat spreader in contact with the SiP device. Also, because the SOA generates more heat than the SiP device, it shows the same tendency as the BOA. Therefore, the thickness of the heat spreader in contact with the SOA must also be thicker than the thickness of the heat spreader in contact with the SiP device.

[0013] In view of the above-mentioned problems, an object of the present disclosure is to provide an optical module that allows heat spreaders in contact with a plurality of heat-generating elements to have an appropriate thickness. [Means for solving the problem]

[0014] An optical module according to one aspect includes: a first heat spreader having a first surface; a second heat spreader having a second surface smaller in area than the first surface, the second surface being in contact with the first surface and attached to the first heat spreader; an optical processing circuit attached to the first heat spreader at a portion of the first surface that is not in contact with the second surface, the optical processing circuit processing and outputting light; an optical amplifier attached to the second heat spreader for amplifying and outputting the light; Equipped with. [Effects of the Invention]

[0015] According to the above-described aspect, it is possible to provide an optical module in which the heat spreaders in contact with the plurality of heat-generating elements (optical processing circuits and optical amplifiers) can have appropriate thicknesses. [Brief explanation of the drawings]

[0016] [Figure 1] 10A and 10B are diagrams illustrating the appropriate thickness of the heat spreader in contact with the BOA. [Figure 2] 1 is a perspective view illustrating an example of the configuration of an optical module according to the present disclosure. [Figure 3] 1 is a front view illustrating an example of the configuration of an optical module according to the present disclosure. [Figure 4] 1 is a front view illustrating an example of the configuration of an optical module according to the present disclosure. [Figure 5] 1 is a perspective view illustrating an example of the configuration of an optical module according to the present disclosure. [Figure 6] 1 is a front view illustrating an example of the configuration of an optical module according to the present disclosure. [Figure 7] 1 is a front view illustrating an example of the configuration of an optical module according to the present disclosure. [Figure 8] 1 is a front view illustrating an example of the configuration of an optical module according to the present disclosure. [Figure 9] 1 is a plan view illustrating an example of the configuration of an optical module according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the following description and drawings have been omitted and simplified as appropriate for clarity of explanation. In addition, the same elements are given the same reference numerals in the following drawings, and duplicated explanations are omitted as necessary. In addition, in the following description, a laser unit will be used as an example of an optical module, but examples of optical modules are not limited to laser units.

[0018] <First Embodiment> An example of the configuration of the optical module 1 will be described with reference to Fig. 2 and Fig. 3. Fig. 2 is a perspective view showing the example of the configuration of the optical module 1, and Fig. 3 is a front view showing the example of the configuration of the optical module 1.

[0019] As shown in FIGS. 2 and 3, the optical module 1 is a laser unit including a first heat spreader 10, a second heat spreader 20, a SiP device 40, and a BOA 50.

[0020] The first heat spreader 10 has a first surface 10S. Specifically, in the examples of Figures 2 and 3, the first heat spreader 10 (first surface 10S) has a rectangular shape in a plan view. However, this is not limited thereto, and the first heat spreader 10 (first surface 10S) may have another shape, such as a square, in a plan view.

[0021] The second heat spreader 20 has a second surface 20S1 that is smaller in area than the first surface 10S. Specifically, in the examples shown in Figures 2 and 3, the second heat spreader 20 (the second surface 20S1 and the opposite surface 20S2) has a Z-shape in which notches are formed at two diagonal corners of a rectangle in a plan view. However, this is not limited thereto, and the second heat spreader 20 (the second surface 20S1 and the opposite surface 20S2) may have other shapes, such as a square shape in which notches are formed at two diagonal corners in a plan view. The second heat spreader 20 is attached to the first heat spreader 10 with the second surface 20S1 and the first surface 10S in contact with each other.

[0022] The SiP element 40 is attached to the first heat spreader 10 at a portion of the first surface 10S that is not in contact with the second surface 20S1. Specifically, in the examples of Figures 2 and 3, the SiP element 40 is attached to the first heat spreader 10 at a portion of the first surface 10S that is not in contact with the second surface 20S1 and that corresponds to one of the two notches described above. The SiP device 40 is an optical processing circuit that processes and outputs light.

[0023] The BOA 50 is attached to the second heat spreader 20 on a surface 20S2 opposite to the second surface 20S1 (that is, the back surface; the same applies hereinafter). The BOA 50 is a CoC (Chip on Carrier) type optical amplifier that amplifies and outputs the light output from the SiP device 40.

[0024] The first heat spreader 10 and the second heat spreader 20 may be formed from different metal plates, or the first heat spreader 10 and the second heat spreader 20 may be formed from a single metal plate.

[0025] As described above, according to the first embodiment, the first heat spreader 10 has a first surface 10S. The second heat spreader 20 has a second surface 20S1 having an area smaller than that of the first surface 10S, and is attached to the first heat spreader 10 with the second surface 20S1 and the first surface 10S in contact with each other. The SiP device 40 is attached to the first heat spreader 10 at a portion of the first surface 10S that is not in contact with the second surface 20S1. The BOA 50 is attached to the second heat spreader 20 at a surface 20S2 opposite to the second surface 20S1.

[0026] Therefore, the thickness of the heat spreader in contact with the SiP element 40 is the thickness of the first heat spreader 10. On the other hand, the thickness of the heat spreader in contact with the BOA 50, which generates more heat than the SiP element 40, is the sum of the thicknesses of the first heat spreader 10 and the second heat spreader 20, and is therefore thicker than the thickness of the heat spreader in contact with the SiP element 40. This allows the heat spreaders in contact with the SiP element 40 and the BOA 50, which are heat generating bodies, to have appropriate thicknesses.

[0027] <Embodiment 2> An example of the configuration of the optical module 2 will be described with reference to Fig. 4. Fig. 4 is a front view showing an example of the configuration of the optical module 2.

[0028] 4, in the optical module 2, the SiP device 40 includes an optical output port 40P that outputs light processed by the SiP device 40. The BOA 50 also includes an optical input port 50P to which the light output from the optical output port 40P is input.

[0029] Here, it is assumed that a first length (length in the z-axis direction) from the bottom surface of the SiP device 40 to the optical output port 40P is L1, and a second length (length in the z-axis direction) from the bottom surface of the BOA 50 to the optical input port 50P is L2. In this case, the thickness Th of the second heat spreader 20 is set to the difference between the above-mentioned first length L1 and the above-mentioned second length L2. In this way, by adjusting the thickness Th of the second heat spreader 20, it is possible to align the positions of the optical output port 40P and the optical input port 50P in the z-axis direction. The other configurations of the optical module 2 are the same as those of the optical module 1 described above.

[0030] As described above, according to the second embodiment, the thickness Th of the second heat spreader 20 is the difference between the first length L1 from the bottom surface of the SiP device 40 to the optical output port 40P and the second length L2 from the bottom surface of the BOA 50 to the optical input port 50P. This allows the positions of the optical output port 40P and the optical input port 50P to coincide with each other. Other effects are the same as those of the first embodiment described above.

[0031] <Third Embodiment> An example of the configuration of the optical module 3 will be described with reference to Fig. 5 and Fig. 6. Fig. 5 is a perspective view showing the example of the configuration of the optical module 3, and Fig. 6 is a front view showing the example of the configuration of the optical module 3.

[0032] As shown in FIGS. 5 and 6, the optical module 3 has a configuration in which an SOA 60 is added to the optical module 1 described above.

[0033] The SOA 60 is attached to the second heat spreader 20 on a surface 20S2 opposite to the second surface 20S1. The SOA 60 is a CoC type light source that outputs light to the SiP device 40 .

[0034] As described above, according to the third embodiment, the SOA 60 is added to the above-described optical module 1. The SOA 60 is attached to the second heat spreader 20 on the surface 20S2 opposite to the second surface 20S1.

[0035] Therefore, the thickness of the heat spreader in contact with the SOA 60, which generates more heat than the SiP element 40, is the sum of the thicknesses of the first heat spreader 10 and the second heat spreader 20, and is therefore thicker than the thickness of the heat spreader in contact with the SiP element 40. This allows the heat spreaders in contact with the SiP element 40, the BOA 50, and the SOA 60, which are heat generating bodies, to have appropriate thicknesses.

[0036] <Fourth Embodiment> An example of the configuration of the optical module 4 will be described with reference to Fig. 7. Fig. 7 is a front view showing an example of the configuration of the optical module 4. As shown in FIG. 7, the optical module 4 has a configuration in which an isolator 70 is added to the optical module 3 described above.

[0037] The isolator 70 is attached to the first heat spreader 10 at a portion of the first surface 10S that is not in contact with the second surface 20S1. Specifically, in the example of FIG. 7, the second heat spreader 20 (the second surface 20S1 and the opposite surface 20S2) has a Z-shape in plan view, with notches formed at two diagonal corners of a rectangle. The isolator 70 is attached to the first heat spreader 10 at a portion of the first surface 10S that is not in contact with the second surface 20S1 and that corresponds to one of the two notches (specifically, the portion of the region 10R in FIG. 5). The SiP element 40 is attached to a portion of the first surface 10S that is not in contact with the second surface 20S1 and that corresponds to the other of the two notches.

[0038] The isolator 70 transmits light output from the BOA 50 only in the output direction (positive x-axis direction) and blocks light in the opposite direction (negative x-axis direction) to the output direction, thereby preventing reflected light of the light output from the BOA 50 from circulating back into the BOA 50.

[0039] As described above, according to the fourth embodiment, the isolator 70 is added to the optical module 3. The isolator 70 is attached to the first heat spreader 10 at a portion of the first surface 10S that is not in contact with the second surface 20S1. This makes it possible to prevent reflected light of light output from the BOA 50 from circulating back into the BOA 50. Other effects are the same as those of the third embodiment described above.

[0040] <Fifth Embodiment> An example of the configuration of the optical module 5 will be described with reference to Fig. 8. Fig. 8 is a front view showing an example of the configuration of the optical module 5.

[0041] As shown in FIG. 8, the optical module 5 has a configuration in which a third heat spreader 30 and an SOA 60 are added to the optical module 1 described above.

[0042] The third heat spreader 30 has a third surface 30S1 having a smaller area than the surface 20S2 opposite to the second surface 20S1, and is attached to the second heat spreader 20 with the third surface 30S1 and the surface 20S2 opposite to the second surface 20S1 in contact with each other.

[0043] Therefore, in the fifth embodiment, the BOA 50 is attached to the second heat spreader 20 at a portion of the surface 20S2 opposite to the second surface 20S1 that is not in contact with the third surface 30S1.

[0044] The SOA 60 is attached to the third heat spreader 30 on a surface 30S2 opposite to the third surface 30S1. Therefore, when the thickness of the BOA 50 is thicker than the thickness of the SOA 60, the difference in thickness between the two can be absorbed by the third heat spreader 30. The SOA 60 is a CoC type light source that outputs light to the SiP device 40 .

[0045] The shape of the third heat spreader 30 (the third surface 30S1 and the opposite surface 30S2) in a plan view is not particularly limited, and may be, for example, a shape with a cutout formed in a part thereof. In this case, the BOA 50 may be attached to the second heat spreader 20 at a portion of the opposite surface 20S2 of the second surface 20S1 that is not in contact with the third surface 30S1 and that corresponds to the cutout described above.

[0046] The first heat spreader 10, the second heat spreader 20, and the third heat spreader 30 may be formed from different metal plates, or the first heat spreader 10, the second heat spreader 20, and the third heat spreader 30 may be formed from a single metal plate.

[0047] As described above, according to the fifth embodiment, the third heat spreader 30 and the SOA 60 are added to the optical module 1. The third heat spreader 30 has a third surface 30S1 having a smaller area than the surface 20S2 opposite to the second surface 20S1, and is attached to the second heat spreader 20 with the third surface 30S1 and the surface 20S2 opposite to the second surface 20S1 in contact with each other. The BOA 50 is attached to the second heat spreader 20 at a portion of the surface 20S2 opposite to the second surface 20S1 that does not contact the third surface 30S1. The SOA 60 is attached to the third heat spreader 30 at the surface 30S2 opposite to the third surface 30S1. As a result, when the thickness of the BOA 50 is thicker than the thickness of the SOA 60, the difference in thickness between the two can be absorbed by the third heat spreader 30. Other effects are the same as those of the first embodiment described above.

[0048] In the fifth embodiment, it is assumed that the thickness of the BOA 50 is greater than the thickness of the SOA 60, but the thickness of the SOA 60 may also be greater than the thickness of the BOA 50. In that case, the SOA 60 may be attached to the second heat spreader 20 at a portion of the surface 20S2 opposite to the second surface 20S1 that is not in contact with the third surface 30S1, and the BOA 50 may be attached to the third heat spreader 30 at the surface 30S2 opposite to the third surface 30S1.

[0049] <Sixth Embodiment> An example of the configuration of the optical module 6 will be described with reference to Fig. 9. Fig. 9 is a plan view showing an example of the configuration of the optical module 6.

[0050] As shown in FIG. 9, the basic configuration of the optical module 6 is the same as that of the optical module 4 described above. The optical module 6 is mounted in a package 80 . The second heat spreader 20 has wiring 20W provided on a surface 20S2 opposite to the second surface 20S1 to connect the terminals 80T of the package 80 and terminals (not shown) of the SiP device 40. Specifically, in the example of Fig. 9, the second heat spreader 20 (the second surface 20S1 and the opposite surface 20S2) has a Z-shape in which notches are formed at two diagonal corners of a rectangle in a plan view. The wiring 20W is formed on the opposite surface 20S2 of the Z-shape in a portion other than the attachment positions of the BOA 50 and the SOA 60.

[0051] As described above, according to the sixth embodiment, the optical module 6 has the same configuration as the optical module 4 described above, and is mounted on the package 80. Furthermore, the second heat spreader 20 has wiring 20W provided on the surface 20S2 opposite to the second surface 20S1 for connecting the terminals 80T of the package 80 and the terminals of the SiP element 40. This allows the terminals 80T of the package 80 and the terminals of the SiP element 40 to be connected to each other. Other effects are the same as those of the fourth embodiment described above.

[0052] Although the present disclosure has been described above with reference to the embodiments, the present disclosure is not limited to the above-described embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present disclosure. Furthermore, each embodiment can be combined with other embodiments as appropriate.

[0053] Furthermore, each drawing is merely an example for describing one or more embodiments. Each drawing may relate not only to one particular embodiment, but also to one or more other embodiments. As will be understood by those skilled in the art, various features described with reference to any one drawing can be combined with features shown in one or more other drawings to create, for example, an embodiment not explicitly shown or described. Not all features shown in any one drawing are necessarily required to describe an exemplary embodiment, and some features may be omitted.

[0054] Furthermore, some or all of the above-described embodiments can be described as, but are not limited to, the following supplementary notes. (Appendix 1) a first heat spreader having a first surface; a second heat spreader having a second surface smaller in area than the first surface, the second surface being in contact with the first surface and attached to the first heat spreader; an optical processing circuit attached to the first heat spreader at a portion of the first surface that is not in contact with the second surface, the optical processing circuit processing and outputting light; an optical amplifier attached to the second heat spreader on the surface opposite to the second surface, the optical amplifier amplifying and outputting the light output from the optical processing circuit; An optical module comprising: (Appendix 2) the optical processing circuit includes an optical output port that outputs the light; the optical amplifier includes an optical input port to which the light output from the optical output port is input; a thickness of the second heat spreader is a difference between a first length from a bottom surface of the optical processing circuit to the optical output port and a second length from a bottom surface of the optical amplifier to the optical input port; 10. The optical module according to claim 1. (Appendix 3) a light source attached to the second heat spreader on the opposite side of the second surface and configured to output light to the optical processing circuit; 10. The optical module according to claim 1. (Appendix 4) an isolator attached to the first heat spreader at a portion of the first surface that is not in contact with the second surface, and transmitting the light output from the optical amplifier in the output direction; 4. The optical module according to claim 3. (Appendix 5) the second heat spreader has a Z-shape in which notches are formed at two diagonal corners of a square or rectangle in a plan view, the isolator is attached to the first heat spreader at a portion of the first surface that is not in contact with the second surface and that corresponds to one of the notches; the optical processing circuit is attached to the first heat spreader at a portion of the first surface that is not in contact with the second surface and that corresponds to the other notch portion; 5. The optical module according to claim 4. (Appendix 6) The optical module is mounted in a package, the second heat spreader has wiring provided on a surface opposite to the second surface for connecting terminals of the package and terminals of the optical processing circuit; 6. The optical module according to claim 5. (Appendix 7) the first heat spreader and the second heat spreader are formed of different metal plates, respectively; 7. An optical module according to any one of claims 1 to 6. (Appendix 8) the first heat spreader and the second heat spreader are formed from a single metal plate; 7. An optical module according to any one of claims 1 to 6. (Appendix 9) a third heat spreader having a third surface smaller in area than the surface opposite to the second surface, the third surface being in contact with the surface opposite to the second surface and attached to the second heat spreader; a light source attached to the third heat spreader on the opposite side of the third surface and configured to output light to the optical processing circuit; the optical amplifier is attached to the second heat spreader at a portion of a surface opposite to the second surface that is not in contact with the third surface; 3. The optical module according to claim 1 or 2. (Appendix 10) the first heat spreader, the second heat spreader, and the third heat spreader are formed from different metal plates; 10. The optical module according to claim 9. (Appendix 11) the first heat spreader, the second heat spreader, and the third heat spreader are formed from a single metal plate; 10. The optical module according to claim 9. [Explanation of symbols]

[0055] 1~6 Optical Module 10 First heat spreader 10S First page 10R area 20 Second heat spreader 20S1 Second Side 20S2 Opposite side of the second surface 20W wiring 30 Third Heat Spreader 30S1 Third Side 30S2 Opposite side of the third surface 40 SiP element (optical processing circuit) 40P optical output port 50 BOA (Bandwidth Amplifier) 50P optical input port 60 SOA (light source) 70 Isolator 80 packages 80T terminal

Claims

1. a first heat spreader having a first surface; a second heat spreader having a second surface smaller in area than the first surface, the second surface being in contact with the first surface and attached to the first heat spreader; an optical processing circuit attached to the first heat spreader at a portion of the first surface that is not in contact with the second surface, the optical processing circuit processing and outputting light; an optical amplifier attached to the second heat spreader on the surface opposite to the second surface, the optical amplifier amplifying and outputting the light output from the optical processing circuit; Equipped with the optical amplifier generates more heat than the optical processing circuit; Optical module.

2. the optical processing circuit includes an optical output port that outputs the light; the optical amplifier includes an optical input port to which the light output from the optical output port is input; a thickness of the second heat spreader is a difference between a first length from a bottom surface of the optical processing circuit to the optical output port and a second length from a bottom surface of the optical amplifier to the optical input port; The optical module according to claim 1 .

3. a light source attached to the second heat spreader on the opposite side of the second surface and configured to output light to the optical processing circuit; The optical module according to claim 1 .

4. an isolator attached to the first heat spreader at a portion of the first surface that is not in contact with the second surface, and transmitting the light output from the optical amplifier in the output direction; The optical module according to claim 3 .

5. the second heat spreader has a Z-shape in which notches are formed at two diagonal corners of a square or rectangle in a plan view, the isolator is attached to the first heat spreader at a portion of the first surface that is not in contact with the second surface and that corresponds to one of the cutout portions; the optical processing circuit is attached to the first heat spreader at a portion of the first surface that is not in contact with the second surface and that corresponds to the other notch portion; The optical module according to claim 4 .

6. The optical module is mounted in a package, the second heat spreader has wiring provided on a surface opposite to the second surface for connecting terminals of the package and terminals of the optical processing circuit; The optical module according to claim 5 .

7. the first heat spreader and the second heat spreader are formed of different metal plates, respectively; The optical module according to claim 1 .

8. the first heat spreader and the second heat spreader are formed from a single metal plate; The optical module according to claim 1 .

9. a third heat spreader having a third surface smaller in area than the surface opposite to the second surface, the third surface being in contact with the surface opposite to the second surface and attached to the second heat spreader; a light source attached to the third heat spreader on a surface opposite to the third surface and configured to output light to the optical processing circuit; the optical amplifier is attached to the second heat spreader at a portion of a surface opposite to the second surface that is not in contact with the third surface; 3. The optical module according to claim 1.

10. the first heat spreader, the second heat spreader, and the third heat spreader are formed of different metal plates; The optical module according to claim 9 .

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