Optical module packaging structure

Abstract

The invention relates to the technical field of optical modules, and discloses an optical module packaging structure which comprises a substrate, a heat dissipation block, a semiconductor refrigerator, a silicon optical chip, a heat insulation piece and an optical fiber array. The substrate is provided with an accommodating hole; the heat dissipation block is arranged in the accommodating hole and is connected with the substrate; the semiconductor cooler is arranged in the accommodating hole, and a gap is formed between the semiconductor cooler and the hole wall of the accommodating hole; the semiconductor cooler is provided with a cold end and a hot end, the hot end is connected with the radiating block, and the gap surrounds the cold end; the silicon optical chip is arranged at the cold end, and the silicon optical chip and the substrate are arranged at an interval; the heat insulation piece is arranged in the gap and separates the silicon optical chip from the substrate; and the optical fiber array is in light conduction with the silicon optical chip. By means of the double isolation design of the gap and the heat insulation piece, a physical heat transfer path is blocked, heat radiation and heat convection are restrained, even if part of heat is transversely diffused to the substrate, the substrate can be prevented from generating the backward flow type heat influence on the silicon optical chip, and the heat dissipation and temperature control precision of the silicon optical chip is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical modules, in particular to an optical module packaging structure. BACKGROUND

[0002] In an optical communication system, an optical module is a core device for converting an optical signal into an electrical signal and converting an electrical signal into an optical signal. The optical module integrates a silicon optical chip, a laser, and a photodiode, etc., and has a large amount of heat generated during operation. The heat dissipation problem becomes a major obstacle to performance.

[0003] For example, Chinese patent application CN109991703A discloses an optical module, which includes a shell, a circuit board located inside the shell, a semiconductor refrigerator embedded in the circuit board, a heat dissipation part of the semiconductor refrigerator in contact with the shell through a heat conduction piece, an optoelectronic chip located on the heat dissipation part of the semiconductor refrigerator, and a lens assembly located on the surface of the circuit board and covering the optoelectronic chip to change the propagation direction of light. The optoelectronic chip is placed on the heat dissipation part of the semiconductor refrigerator, so that the heat generated by the optoelectronic chip can be conducted away by the semiconductor refrigerator. The heat dissipation part of the semiconductor refrigerator is in contact with the shell through the heat conduction piece, so that the heat can be conducted to the shell, and finally dissipated through the shell.

[0004] In the existing optical module, the semiconductor refrigerator is embedded in the circuit board, and the heat dissipation part thereof is in contact with the shell through a heat conduction piece to conduct heat. However, the semiconductor refrigerator is directly fixed in the through hole of the circuit board by glue, and the heat dissipation part thereof conducts part of the heat to the circuit board. The temperature near the edge of the through hole of the circuit board is relatively high, which easily affects the heat dissipation and temperature control effect of the optoelectronic chip. SUMMARY

[0005] The technical problem to be solved by the present application is that the semiconductor refrigerator is directly fixed in the through hole of the circuit board by glue, and the heat dissipation part thereof conducts part of the heat to the circuit board. The temperature near the edge of the through hole of the circuit board is relatively high, which easily affects the heat dissipation and temperature control effect of the optoelectronic chip.

[0006] To solve the above technical problems, the present application provides a technical scheme of an optical module packaging structure: The optical module packaging structure comprises: a substrate having a receiving hole; a heat dissipation block arranged in the receiving hole and connected with the substrate; a semiconductor refrigerator arranged in the receiving hole, wherein a gap is arranged between the semiconductor refrigerator and the hole wall of the receiving hole; the semiconductor refrigerator has an upper cold end and a lower hot end, the hot end is connected with the heat dissipation block, and the gap surrounds the cold end; a silicon optical chip arranged on the cold end and spaced apart from the substrate; A heat insulation piece is arranged in the gap and separates the silicon optical chip and the substrate. An optical fiber array is arranged on the upper side of the substrate and is in optical communication with the silicon optical chip.

[0007] Further, a convex part is arranged in the middle of the heat dissipation block, the convex part is embedded in the accommodating hole, the hot end is connected with the convex part, the edge of the heat dissipation block is provided with a stepped part surrounding the convex part, and the stepped part is in abutment with the substrate.

[0008] Further, the minimum width of the gap is d, and 2mm≤d≤5mm is satisfied.

[0009] Further, the heat insulation piece is polyurethane glue, the thermal conductivity thereof is ≤0.3W / (m·K), and the thermal expansion coefficient thereof is ≤50ppm / ℃.

[0010] Further, the hole wall of the accommodating hole is provided with a first reflection layer, the first reflection layer is arranged at intervals around the semiconductor refrigerator, and the heat insulation piece is filled between the first reflection layer and the semiconductor refrigerator.

[0011] Further, the hot end is also provided with a second reflection layer, the second reflection layer is wrapped on the upper surface and the side surface of the hot end, the second reflection layer is arranged at intervals above and below the cold end, the heat insulation piece is filled between the second reflection layer and the cold end, and between the second reflection layer and the first reflection layer.

[0012] Further, the first reflection layer and the second reflection layer are both tin foil layers, the light surface of the tin foil layer is attached to the hole wall of the accommodating hole and the surface of the hot end, and the other side surface of the tin foil layer is bonded with the heat insulation piece.

[0013] Further, the optical module packaging structure further comprises a laser and a PD element, the laser and the PD element are both arranged on the silicon optical chip and are electrically connected with the silicon optical chip, and the optical fiber array is in optical communication with the laser and the PD element.

[0014] Further, the optical module packaging structure further comprises a lens assembly, the lens assembly is arranged on the silicon optical chip, and a waveguide is arranged between the lens assembly and the laser, and the optical fiber array is in optical communication with the lens assembly. The optical module packaging structure further comprises an MPD element, the MPD element is arranged on the silicon optical chip and is electrically connected with the silicon optical chip, and the MPD element is used for detecting and adjusting the optical power output by the laser.

[0015] Further, the optical module packaging structure further comprises a driver and a transimpedance amplifier, both of which are arranged on the silicon optical chip and electrically connected with the silicon optical chip.

[0016] The optical module packaging structure of the present application has the following advantages: the optical module packaging structure adopts the design form of a substrate, a heat sink, a semiconductor refrigerator, a silicon optical chip, a thermal insulation piece and a fiber array, the substrate is provided with a receiving hole, the heat sink and the semiconductor refrigerator are arranged in the receiving hole, and the receiving hole provides mounting space for the heat sink and the semiconductor refrigerator. The hot end of the semiconductor refrigerator is connected with the heat sink, and the silicon optical chip is arranged at the cold end of the semiconductor refrigerator. The heat can be directly conducted to the housing or other components through the heat sink, thereby reducing the heat diffusion to the silicon optical chip.

[0017] Further, a gap is arranged between the semiconductor refrigerator and the hole wall of the receiving hole, and the gap surrounds the cold end. The gap can block the heat conduction path, thereby reducing the heat transfer between the semiconductor refrigerator (especially the cold end) and the substrate. The silicon optical chip is arranged apart from the substrate, the thermal insulation piece is arranged in the gap and separates the silicon optical chip and the substrate. The thermal insulation piece has low thermal conductivity, thereby further blocking the radiation conduction and convection effect of the heat from the semiconductor refrigerator to the substrate. Meanwhile, the thermal insulation piece effectively isolates the heat exchange between the substrate and the silicon optical chip, avoids the direct contact of the silicon optical chip with the substrate, and prevents the secondary heat influence of the heated area of the substrate on the silicon optical chip.

[0018] Through the double isolation design of the gap and the thermal insulation piece, the physical heat conduction path can be blocked, and the heat radiation and convection heat exchange can be inhibited. The heat can be concentrated to the housing or other components by the heat sink. Even if part of the heat diffuses to the substrate, the substrate can also avoid the "backflow type" heat influence on the silicon optical chip. Not only the heat dissipation and temperature control precision of the silicon optical chip are improved, but also the long-term reliability of the optical module in the high-speed operation state is enhanced, thereby realizing the miniaturization and high performance of the high-speed optical communication module. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a perspective view of the optical module packaging structure in the embodiment of the present application; Figure 2 is a perspective view of the substrate of the optical module packaging structure in the embodiment of the present application; Figure 3 is a perspective view of the silicon optical chip of the optical module packaging structure in the embodiment of the present application; Figure 4 is a perspective view of the optical module packaging structure (without the fiber array) in the embodiment of the present application; Figure 5 is a partial sectional view of the optical module packaging structure in the embodiment of the present application; Figure 1 is a partial sectional view of the optical module packaging structure in the embodiment of the present application;Figure 6 is Figure 5 is a partial enlarged view of the substrate, the heat sink, the semiconductor refrigerator, the silicon optical chip and the thermal insulation piece; Figure 7 is a plan structure diagram of the silicon optical chip in the embodiment of the present application; In the figure: 1, substrate; 11, accommodating hole; 12, gap; 13, first reflection layer; 14, second reflection layer; 2, heat sink; 21, convex part; 22, stepped part; 3, semiconductor refrigerator; 31, cold end; 32, hot end; 4, silicon optical chip; 41, laser; 42, PD element; 43, lens assembly; 44, MPD element; 45, driver; 46, transimpedance amplifier; 47, waveguide; 5, thermal insulation piece; 6, optical fiber array; 61, MPO connector. DETAILED DESCRIPTION

[0020] The specific embodiments of the present application will be further described in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present application, but are not used to limit the scope of the present application.

[0021] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like in the present application are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0022] In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0023] In the present application, unless otherwise specifically defined and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral; it can be directly connected, or indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0024] AsFigures 1 to 6 As shown, the optical module packaging structure of the embodiment of the present application comprises a substrate 1, a heat sink 2, a semiconductor refrigerator 3, a silicon optical chip 4, a thermal insulation member 5 and an optical fiber array 6. The substrate 1 is provided with a receiving hole 11. The heat sink 2 is arranged in the receiving hole 11 and connected with the substrate 1. The semiconductor refrigerator 3 is arranged in the receiving hole 11, and a gap 12 is arranged between the semiconductor refrigerator 3 and the hole wall of the receiving hole 11.

[0025] The semiconductor refrigerator 3 has an upper cold end 31 and a lower hot end 32. The hot end 32 is connected with the heat sink 2, and the gap 12 surrounds the cold end 31. The silicon optical chip 4 is arranged on the cold end 31, and the silicon optical chip 4 is arranged spaced apart from the substrate 1. The thermal insulation member 5 is arranged in the gap 12, and the thermal insulation member 5 separates the silicon optical chip 4 and the substrate 1. The optical fiber array 6 is arranged on the upper side of the substrate 1, and the optical fiber array 6 is optically connected with the silicon optical chip 4.

[0026] The optical module packaging structure adopts the design form of the substrate 1, the heat sink 2, the semiconductor refrigerator 3, the silicon optical chip 4, the thermal insulation member 5 and the optical fiber array 6. The substrate 1 is provided with the receiving hole 11. The heat sink 2 and the semiconductor refrigerator 3 are arranged in the receiving hole 11, and the receiving hole 11 provides mounting space for the heat sink 2 and the semiconductor refrigerator 3. The hot end 32 of the semiconductor refrigerator 3 is connected with the heat sink 2. The silicon optical chip 4 is arranged on the cold end 31 of the semiconductor refrigerator 3. The heat can be directly conducted to the shell or other components through the heat sink 2, reducing the heat diffusion to the silicon optical chip 4.

[0027] In addition, the gap 12 is arranged between the semiconductor refrigerator 3 and the hole wall of the receiving hole 11, and the gap 12 surrounds the cold end 31. The gap 12 can block the heat conduction path, reducing the heat transfer between the semiconductor refrigerator 3 (especially the cold end 31) and the substrate 1. The silicon optical chip 4 is arranged spaced apart from the substrate 1. The thermal insulation member 5 is arranged in the gap 12 and separates the silicon optical chip 4 and the substrate 1. The thermal insulation member 5 has low thermal conductivity, further blocking the radiation conduction and convection effect of the heat from the semiconductor refrigerator 3 to the substrate 1, effectively isolating the heat exchange between the substrate 1 and the silicon optical chip 4, avoiding the direct contact of the silicon optical chip 4 with the substrate 1, and preventing the secondary heat influence of the heated area of the substrate 1 on the silicon optical chip 4.

[0028] Through the double isolation design of the gap 12 and the thermal insulation member 5, the physical heat conduction path can be blocked and the heat radiation and convection heat transfer can be inhibited, ensuring that the heat sink 2 concentrates the heat to the shell or other components. Even if part of the heat diffuses to the substrate 1, the substrate 1 can also avoid the "backflow type" heat influence on the silicon optical chip 4. Not only the heat dissipation and temperature control precision of the silicon optical chip 4 is improved, but also the long-term reliability of the optical module in the high-speed running state is enhanced, so that the miniaturization and high performance of the high-speed optical communication module can be realized.

[0029] In this embodiment, the heat sink 2 has a protrusion 21 in the middle, which is embedded in the receiving hole 11. The hot end 32 is connected to the protrusion 21. The edge of the heat sink 2 has a stepped portion 22 surrounding the protrusion 21, which abuts against the substrate 1. The protrusion 21 and the stepped portion 22 ensure that the heat sink 2 is accurately embedded on the substrate 1. Furthermore, by utilizing the partial height overlap between the protrusion 21 and the substrate 1, the impact of the heat sink 2 on the overall thickness of the optical module is reduced.

[0030] As a further preferred embodiment, the minimum width of the gap 12 is d, for example, d=3mm. This size of gap 12 can ensure the interruption of the heat radiation path while avoiding excessive area occupied by the receiving hole 11 on the substrate 1. In some embodiments, to meet different usage requirements, the minimum width d of the gap 12 can be 2mm, 2.5mm, 3.5mm, 4mm, 4.5mm, or 5mm, or any other value between 2mm and 5mm.

[0031] In this embodiment, the heat insulation component 5 is made of polyurethane adhesive with a thermal conductivity ≤0.3W / (m·K) and a coefficient of thermal expansion ≤50ppm / ℃. For example, the selected polyurethane adhesive has a thermal conductivity of 0.2W / (m·K) and a coefficient of thermal expansion of 45ppm / ℃, ensuring that the heat insulation component 5 provides reliable heat insulation while preventing cracking stress caused by its own thermal expansion, thus ensuring the connection stability between the silicon photonic chip 4, the substrate 1, and the semiconductor cooler 3.

[0032] The accommodating hole 11 has a first reflective layer 13 on its wall, and the first reflective layer 13 is arranged at intervals around the semiconductor cooler 3. The heat insulation element 5 is filled between the first reflective layer 13 and the semiconductor cooler 3. The first reflective layer 13 is provided on the wall of the accommodating hole 11 and plays an infrared heat reflection role for the substrate 1. Since the substrate 1 absorbs part of the heat from the hot end 32 of the semiconductor cooler 3, the first reflective layer 13 prevents the heated area of ​​the substrate 1 from transferring heat to the cold end 31 of the semiconductor cooler 3 and the silicon photonic chip 4 in the form of spatial radiation.

[0033] Furthermore, the hot end 32 is also provided with a second reflective layer 14, which covers the upper surface and sides of the hot end 32. The second reflective layer 14 is arranged vertically and vertically with the cold end 31. The heat insulation element 5 is filled between the second reflective layer 14 and the cold end 31, and between the second reflective layer 14 and the first reflective layer 13. Similarly, the second reflective layer 14 plays an infrared heat reflection role on the upper surface and sides of the hot end 32, preventing the hot end 32 from directly transferring heat to the cold end 31 and the silicon photonic chip 4 in the form of spatial radiation.

[0034] The first reflective layer 13, the heat insulation component 5, and the second reflective layer 14 form a composite heat insulation structure, which can completely block the heat transfer path, allowing heat to be transferred more accurately along the heat dissipation path, and keeping the silicon photonic chip 4 in an independent and stable local thermal environment, thus ensuring the long-term operational reliability of the high-speed optical module under high-performance conditions.

[0035] Both the first reflective layer 13 and the second reflective layer 14 are tin foil layers. The smooth side of the tin foil layer is bonded to the wall of the receiving hole 11 and the surface of the hot end 32, while the other side of the tin foil layer is bonded to the heat insulation component 5. The tin foil layer has good ductility, and a thinner thickness can produce an effective heat reflection effect. The rough side of the tin foil layer is bonded to the heat insulation component, which not only provides reliable physical adhesion but also avoids air gaps and interlayer contact thermal resistance, thus improving the thermal performance of the entire optical module packaging structure.

[0036] In this embodiment, as Figure 7 As shown, the optical module packaging structure also includes a laser 41 and a PD element 42. Both the laser 41 and the PD element 42 are mounted on the silicon photonic chip 4 and electrically connected to it. The fiber optic array 6 is optically connected to the laser 41 and the PD element 42. Furthermore, the optical module packaging structure also includes a lens assembly 43, which is mounted on the silicon photonic chip 4. A waveguide 47 is provided between the lens assembly 43 and the laser 41, and the fiber optic array 6 is optically connected to the lens assembly 43. The laser 41 emits an optical signal, which is transmitted to the lens assembly 43 via the waveguide 47. After collimation and / or focusing coupling by the lens assembly 43, the signal is input into the fiber optic array 6. The PD element 42 receives the optical signal from the fiber optic array 6 and converts it into an electrical signal.

[0037] In addition, the optical module packaging structure also includes an MPD element 44, which is disposed on and electrically connected to the silicon photonic chip 4. The MPD element 44 is used to detect and adjust the optical power output of the laser 41. The optical module packaging structure also includes a driver 45 and a transimpedance amplifier 46, both of which are disposed on and electrically connected to the silicon photonic chip 4. It should be noted that an MPO connector 61 is provided at the end of the fiber array 6 away from the silicon photonic chip 4, through which optical communication with the device is achieved.

[0038] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. An optical module package structure, characterized by, include: The substrate (1) has a receiving hole (11); A heat sink (2) is disposed in the receiving hole (11) and connected to the substrate (1); A semiconductor cooler (3) is disposed in the receiving hole (11), and a gap (12) is provided between the semiconductor cooler (3) and the hole wall of the receiving hole (11); the semiconductor cooler (3) has a cold end (31) and a hot end (32) that are opposite to each other, the hot end (32) is connected to the heat sink (2), and the gap (12) surrounds the cold end (31). A silicon photonic chip (4) is disposed at the cold end (31), and the silicon photonic chip (4) is arranged at a distance from the substrate (1); A heat insulation element (5) is disposed in the gap (12), and the heat insulation element (5) separates the silicon photonic chip (4) and the substrate (1). An optical fiber array (6) is disposed on the upper side of the substrate (1), and the optical fiber array (6) is optically connected to the silicon photonic chip (4).

2. The optical module package structure according to claim 1, wherein, The heat sink (2) has a protrusion (21) in the middle, which is embedded in the receiving hole (11). The hot end (32) is connected to the protrusion (21). The edge of the heat sink (2) has a step (22) surrounding the protrusion (21), which abuts against the substrate (1).

3. The optical module package structure according to claim 2, wherein The minimum width of the gap (12) is d, which satisfies: 2mm≤d≤5mm.

4. The optical module package structure according to any one of claims 1 to 3, characterized in that, The heat insulation component (5) is a polyurethane adhesive with a thermal conductivity of ≤0.3W / (m·K) and a coefficient of thermal expansion of ≤50ppm / ℃.

5. The optical module package structure according to claim 4, wherein The accommodating hole (11) has a first reflective layer (13) on its wall, and the first reflective layer (13) is arranged at intervals around the semiconductor cooler (3), and the heat insulation member (5) is filled between the first reflective layer (13) and the semiconductor cooler (3).

6. The optical module package structure according to claim 5, wherein, The hot end (32) is also provided with a second reflective layer (14), which covers the upper surface and side surface of the hot end (32). The second reflective layer (14) and the cold end (31) are arranged vertically at intervals. The heat insulation element (5) is filled between the second reflective layer (14) and the cold end (31), and between the second reflective layer (14) and the first reflective layer (13).

7. The optical module package structure according to claim 6, wherein The first reflective layer (13) and the second reflective layer (14) are both tin foil layers. The smooth surface of the tin foil layer is attached to the hole wall of the receiving hole (11) and the surface of the hot end (32). The other side of the tin foil layer is bonded to the heat insulation component (5).

8. The optical module package structure according to any one of claims 1 to 3, wherein, The optical module packaging structure also includes a laser (41) and a PD element (42). The laser (41) and the PD element (42) are both disposed on the silicon photonic chip (4) and electrically connected to the silicon photonic chip (4). The fiber array (6) is optically connected to the laser (41) and the PD element (42).

9. The optical module package structure according to claim 8, wherein, The optical module packaging structure further comprises a lens assembly (43) arranged on the silicon optical chip (4), and a waveguide (47) is arranged between the lens assembly (43) and the laser (41), and the optical fiber array (6) is in optical communication with the lens assembly (43); The optical module packaging structure further comprises an MPD element (44) arranged on the silicon optical chip (4) and electrically connected with the silicon optical chip (4), and the MPD element (44) is used for detecting and adjusting the optical power output by the laser (41).

10. The optical module package structure of claim 8, wherein, The optical module packaging structure further comprises a driver (45) and a transimpedance amplifier (46), both of which are arranged on the silicon optical chip (4) and electrically connected with the silicon optical chip (4).

Images