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 that is configured by combining a SiP (Silicon Photonics) element with an SOA (Semiconductor Optical Amplifier) ​​and a BOA (Booster Optical Amplifier). In the above-mentioned laser unit, the SiP element, the SOA, and the BOA become heat generating bodies, and temperature control is required.

[0003] Here, in order to cool a heat generating element with lower power consumption in a thermo electric cooler (TEC), it is effective to increase the heat absorption efficiency of the TEC. In addition, in order to increase the heat absorption efficiency of the TEC, it is effective to have a structure in which the heat from the heating element is evenly diffused throughout the TEC using a heat spreader. A heat dissipation mechanism using a heat spreader is disclosed in, for example, Patent Document 1.

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

[0005] [Patent Document 1] JP 2019-145536 A Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, in the above-mentioned 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] In addition, when considering the structural aspects of the laser unit described above, it is effective to use the same heat spreader for the heat spreaders in contact with the SiP element, the SOA, and the BOA. However, in this structure, even though the SOA and the BOA generate more heat than the SiP element, the thickness of the heat spreader in contact with the SOA and the BOA ends up being the same as that of the heat spreader in contact with the SiP element. Therefore, the above structure has a problem in that the heat of the SOA and the BOA cannot be sufficiently diffused.

[0008] The above-mentioned problems will be explained below with reference to Fig. 1, taking the BOA as an example of the SOA and the BOA. The upper diagram in Fig. 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 Fig. 1 shows the state of heat diffusion in 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 about 200 μm, the bottom heat dissipation width cannot be secured sufficiently. Therefore, the heat spreader in contact with the BOA does not dissipate heat sufficiently, and the heat absorption efficiency of the TEC is poor. However, the temperature rise of the heat spreader in contact with the BOA is accommodated.

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

[0011] Therefore, if the thickness of the heat spreader in contact with the SiP element is constant at approximately 200 μm, if the thickness of the heat spreader in contact with the BOA is made 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, the SOA generates more heat than the SiP device, so it shows the same tendency as the BOA. Therefore, the thickness of the heat spreader in contact with the SOA must 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 the heat spreaders in contact with each of a plurality of elements that become heat generating bodies to have an appropriate thickness. [Means for solving the problem]

[0014] According to one aspect, 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, 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 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. Effect 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 description of the drawings]

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

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

[0018] <Embodiment 1> 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 element 40, and a BOA 50.

[0020] The first heat spreader 10 has a first surface 10S. Specifically, in the examples of Fig. 2 and Fig. 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 example of Fig. 2 and Fig. 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 another shape, such as a shape in which notches are formed at two diagonal corners of a square 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 example of Fig. 2 and Fig. 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 at a surface 20S2 opposite to the second surface 20S1 (that is, the back surface; the same applies below). 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 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. 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. In addition, the BOA 50 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 manner, 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. Other configurations of the optical module 2 are similar to 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. The other effects are the same as those of the first embodiment described above.

[0031] <Embodiment 3> 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-mentioned 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, BOA 50, and SOA 60, which are heat generating elements, 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 which notches are formed at two diagonal corners of a rectangle in a plan view. 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 above-mentioned 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 above-mentioned two notches.

[0038] The isolator 70 transmits the light output from the BOA 50 only in the output direction (x-axis positive direction) and blocks the light in the opposite direction (x-axis negative direction) to the output direction. This makes it possible to prevent reflected light of the light output from the BOA 50 from circulating around the BOA 50.

[0039] As described above, according to the fourth embodiment, the isolator 70 is added to the above-mentioned 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 around the BOA 50. The other effects are the same as those of the third embodiment described above.

[0040] <Fifth Preferred 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 an area smaller than the opposite surface 20S2 of the second surface 20S1, and is attached to the second heat spreader 20 with the third surface 30S1 and the opposite surface 20S2 of 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 in which a notch is formed in a part. 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 above-mentioned notch.

[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 described above. 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 after the third surface 30S1 and the surface 20S2 opposite to the second surface 20S1 are 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 is not in contact with 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. In this way, 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 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 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 similar to that of the optical module 4 described above. The optical module 6 is mounted in a package 80 . The second heat spreader 20 is provided with wiring 20W for connecting the terminal 80T of the package 80 and a terminal (not shown) of the SiP element 40 on a surface 20S2 opposite to the second surface 20S1. 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 is provided on the surface 20S2 opposite to the second surface 20S1 with wiring 20W 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. The 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-mentioned embodiments. Various modifications that can be understood by a person 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 appropriately combined with other embodiments.

[0053] Moreover, each drawing is merely an example for describing one or more embodiments. Each drawing may not relate to only one particular embodiment, but may relate to one or more other embodiments. As can be understood by those skilled in the art, various features described with reference to any one drawing may be combined with features shown in one or more other drawings to create an embodiment not explicitly shown or described, for example. 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 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 a 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 for outputting 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; 2. The optical module according to claim 1. (Appendix 3) a light source attached to the second heat spreader on a surface opposite the second surface and configured to output light to the optical processing circuit; 2. The optical module according to claim 1. (Appendix 4) an isolator attached to the first heat spreader at a portion of the first surface not in contact with the second surface, the isolator 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 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 corresponds to the other of the notches; 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 a terminal of the package and a terminal 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, 7. The optical module according to claim 1. (Appendix 8) the first heat spreader and the second heat spreader are formed of a single metal plate; 7. The optical module according to claim 1. (Appendix 9) a third heat spreader having a third surface smaller in area than an opposite surface of the second surface, the third surface being in contact with the opposite surface of the second surface and attached to the second heat spreader; a light source attached to the third heat spreader on a surface opposite 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 of 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 of 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 elements (optical processing circuits) 40P optical output port 50 BOA (optical 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 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 a surface opposite to the second surface, the optical amplifier amplifying and outputting the light output from the optical processing circuit; An optical module comprising:

2. the optical processing circuit includes an optical output port for outputting 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 a surface opposite the second surface and configured to output light to the light 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 not in contact with the second surface, the isolator transmitting light output from the optical amplifier in an output direction of the light; 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 corresponds to the other of the notches; 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 a terminal of the package and a terminal 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, The optical module according to claim 1 .

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

9. a third heat spreader having a third surface smaller in area than an opposite surface of the second surface, the third surface being in contact with the opposite surface of the second surface and attached to the second heat spreader; a light source attached to the third heat spreader on a surface opposite 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.

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.

Images