400G DR4 light engine capable of enhancing light path stability
By adding the size of the upper ceramic substrate in the 400G DR4 optical engine and using a combination of thermal insulation board and soft thermal paste, the height difference error and temperature difference caused by thickness tolerance in traditional optical engines are solved, and higher coupling efficiency, higher yield and more stable optical paths are achieved.
Patent Information
- Application Number
- CN202421942582.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-09
- Publication Date
- 2025-05-06
- Estimated Expiration
- 2034-08-09
AI Technical Summary
In the traditional 400G DR4 optical engine, the thickness tolerance of the TEC refrigerator leads to a large height difference between the ceramic heat sink and the PCB board, affecting the performance of high-frequency gold wires and the coupling efficiency of the EML chip and the optical fiber array. The temperature difference between the optical components is too large, resulting in a decrease in the stability of the optical path.
By increasing the size of the upper ceramic substrate and fixing the ceramic heat sink and fiber array to the upper ceramic substrate in the TEC cooler, ensure that the EML chip and the fiber array are less error in the height direction. At the same time, the combination of heat insulation plate and soft thermal paste is used to reduce the thickness tolerance of the TEC refrigerator and improve the optical path stability.
It effectively improves the coupling efficiency and yield of EML chips and fiber arrays, reduces the temperature difference of optical components, improves the stability of the optical path, and reduces costs and maintains stable power consumption.
Smart Images
Figure CN222838241U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of optical engines, and in particular to a 400G DR4 optical engine with enhanced optical path stability. Background Art
[0002] Traditional 400G DR4 optical engines generally use TEC coolers to control the temperature of the EML chip. The structure of the 400G DR4 optical engine is as follows: Figure 1 , 2 As shown, it includes: a base made of tungsten copper and a PCB board placed on the base, a through hole penetrating the upper and lower surfaces of the PCB board is provided in a part of the area corresponding to the base, a TEC cooler and an optical fiber array fixed to the upper surface of the base are arranged in the through hole, the TEC cooler is lower than the upper surface of the PCB board, the TEC cooler is bonded to the PCB board with gold wires, a plurality of ceramic heat sinks bonded to the PCB board with gold wires are fixed on the TEC cooler, an EML chip coupled to the optical fiber array is fixed on each ceramic heat sink, a lens and an optical isolator are coupled in sequence between each EML chip and the optical fiber array in the through hole along the light propagation direction, the lens is fixed to the TEC cooler with ultraviolet glue, and the optical isolator is fixed on the optical port side of the optical fiber array.
[0003] The TEC cooler used in the 400G DR4 optical engine in this solution consists of a TEC cooling chip and an upper ceramic substrate and a lower ceramic substrate located above and below the TEC cooling chip. The electrodes of the TEC cooler are located on the lower ceramic substrate. Usually, the TEC cooler has a thickness tolerance of ±75um, and the thickness tolerance is generated when the upper ceramic substrate + TEC cooling chip + lower ceramic substrate are welded and fixed. The thickness accuracy of the upper ceramic substrate is ±10um. Since the TEC cooler and the optical fiber array are fixed on the same upper surface of the base, the height error of the EML chip and the optical fiber array core is relatively large, which will cause the following three defects:
[0004] 1) The height difference error between the ceramic heat sink and the upper surface of the PCB is relatively large, which causes the high-frequency gold wire to become longer and the high-frequency performance to decrease when the ceramic heat sink and the PCB are bonded by high-frequency gold wire. In addition, the height error between the EML chip and the fiber array core is relatively large, the coupling efficiency decreases, and the yield deteriorates;
[0005] 2) The thickness error of the UV glue under the lens is large, which reduces the reliability of the lens, reduces the coupling efficiency, and deteriorates the yield;
[0006] 3) When working at high temperature, the EML chip and lens are on the cold side of the TEC cooler, while the optical fiber array is on the hot side of the TEC cooler. Specifically, it can be understood that the heat generated by the hot side of the TEC cooler can be conducted to the optical fiber array through the tungsten copper base. Since tungsten copper is a material with high thermal conductivity, the thermal conductivity is usually ~180W / mk, so the temperature difference between the three optical components is too large, and the stability of the optical path is reduced; when working at low temperature, the EML chip and lens are on the hot side of the TEC cooler, while the optical fiber array is on the cold side of the TEC cooler, which also leads to a large temperature difference between the three optical components and a decrease in the stability of the optical path. Utility Model Content
[0007] The technical problem to be solved by the utility model is to provide a 400G DR4 optical engine with enhanced optical path stability to overcome the deficiencies in the above-mentioned prior art.
[0008] The utility model solves the above technical problems with the following technical solutions: a 400GDR4 optical engine with enhanced optical path stability, comprising: a base made of tungsten copper and a PCB board placed on the base, a through hole penetrating the upper and lower surfaces of the PCB board is provided in a partial area corresponding to the base, a heat insulation board fixed to the upper surface of the base and lower than the upper surface of the PCB board is arranged in the through hole, the thermal conductivity of the heat insulation board is lower than the thermal conductivity of tungsten copper, a TEC cooler lower than the upper surface of the PCB board is suspended in the through hole, an upper ceramic substrate in the TEC cooler horizontally extends outward to the top of the heat insulation board and is fixed to the heat insulation board, a gap larger than the thickness tolerance of the TEC cooler is provided between the lower surface of the lower ceramic substrate in the TEC cooler and the upper surface of the base, the gap is filled with soft thermal conductive paste, a plurality of ceramic heat sinks bonded to the PCB board with gold wires are fixed on the upper surface of the upper ceramic substrate in the area above the TEC cooling chip, an EML chip is fixed on each ceramic heat sink, and an optical fiber array coupled to all the EML chips is fixed on the upper surface of the upper ceramic substrate in the area above the heat insulation board.
[0009] The beneficial effects of the utility model are:
[0010] By increasing the size of the upper ceramic substrate and fixing the ceramic heat sink and the optical fiber array on the upper ceramic substrate in the TEC cooler, the height error between the EML chip and the optical fiber array core can be kept small, effectively improving the coupling efficiency and significantly increasing the yield.
[0011] By fixing the extended section of the upper ceramic substrate to the heat insulation board, the TEC cooler can be kept suspended, and a gap larger than the thickness tolerance of the TEC cooler is formed between the lower surface of the lower ceramic substrate in the TEC cooler and the upper surface of the base. Therefore, only the thickness tolerance of the upper ceramic substrate of ±10um needs to be considered, which is significantly smaller than the thickness tolerance of ±75um, thereby ensuring that the error in the height direction of the ceramic heat sink and the PCB board is small, making the high-frequency gold wire length shorter and the high-frequency performance improved;
[0012] Since the ceramic heat sink and the optical fiber array are fixed on the upper ceramic substrate in the TEC cooler, when the 400G DR4 optical engine with enhanced optical path stability is working at high temperature, the EML chip and the optical fiber array are both on the cold side of the TEC cooler, the temperature difference between them is small, the deformation caused by temperature is small, and the optical path is more stable. When the 400G DR4 optical engine with enhanced optical path stability is working at low temperature, the EML chip and the optical fiber array are both on the hot side of the TEC cooler, the temperature difference between them is also small, the deformation caused by temperature is also small, and the optical path is more stable.
[0013] This TEC cooler only increases the size of the upper ceramic substrate without increasing the number of TEC cooling chips. Therefore, compared with a TEC cooler with a larger size and an increased number of TEC cooling chips, it can effectively reduce costs while ensuring the structural stability of the TEC cooler, while the power consumption remains unchanged.
[0014] On the basis of the above technical solution, the present invention can also be improved as follows.
[0015] Furthermore, a gap height between the lower surface of the lower ceramic substrate and the upper surface of the base is 300 um.
[0016] A further beneficial effect of the above method is that the gap is much larger than the ±75um thickness tolerance of the TEC cooler, thereby effectively absorbing the thickness tolerance of the TEC cooler and facilitating the filling of the soft thermal conductive paste.
[0017] Furthermore, a lens and an optical isolator are coupled in sequence between each EML chip and the optical fiber array along the light propagation direction. The lens is fixed to the upper ceramic substrate by ultraviolet glue, and the optical isolator is fixed on the optical port side of the optical fiber array.
[0018] The further beneficial effect of adopting the above method is: since the present solution can ensure that the error between the EML chip and the fiber array core in the height direction is small, the thickness tolerance of the UV glue under the lens is small, the reliability is higher, and the coupling efficiency and yield are improved.
[0019] Furthermore, four ceramic heat sinks are fixed on the upper surface of the upper ceramic substrate along the width direction of the PCB board, and an EML chip coupled to the optical fiber array is fixed on each ceramic heat sink. The number of lenses is four, the number of optical isolators is four, and the optical fiber array is a four-channel optical fiber array.
[0020] Furthermore, the thermal coefficient of the soft thermal paste is greater than 10 W / mk.
[0021] A further beneficial effect of the above method is that even if the TEC cooler is in a suspended state, the TEC cooler can effectively conduct heat with the base through the soft thermal conductive paste.
[0022] Furthermore, the upper ceramic substrate and the heat insulation board are fixed by bonding.
[0023] Furthermore, the material of the heat insulation board is quartz.
[0024] A further beneficial effect of the above is that the thermal conductivity of quartz is very low, only ~1W / mk, and it can be used as a heat insulation board. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 It is a top view of a 400G DR4 optical engine in the prior art;
[0026] Figure 2 This is a main view of a 400G DR4 optical engine in the prior art;
[0027] Figure 3 A top view of a 400G DR4 optical engine with enhanced optical path stability in the present invention;
[0028] Figure 4 This is a front view of the 400G DR4 optical engine with enhanced optical path stability in the present invention.
[0029] In the accompanying drawings, the components represented by the reference numerals are listed as follows:
[0030] 1. Base, 2. PCB board, 210. Through hole, 3. Heat insulation board, 4. TEC cooler, 410. Upper ceramic substrate, 420. TEC cooling chip, 430. Lower ceramic substrate, 5. Ceramic heat sink, 6. EML chip, 7. Optical fiber array, 8. Lens, 9. Optical isolator, 10. Soft thermal paste. DETAILED DESCRIPTION
[0031] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.
[0032] Example 1
[0033] like Figure 3 , Figure 4 As shown, a 400G DR4 optical engine with enhanced optical path stability includes: a base 1 and a PCB board 2, the base 1 is made of tungsten copper, the PCB board 2 is placed on the base 1, a through hole 210 is provided on the PCB board 2 in a part of the area corresponding to the base 1 and passing through the upper and lower surfaces thereof, a heat insulation board 3 fixed to the upper surface of the base 1 and lower than the upper surface of the PCB board 2 is arranged in the through hole 210, the thermal conductivity of the heat insulation board 3 is lower than the thermal conductivity of tungsten copper, a TEC cooler 4 is suspended in the through hole 210 and lower than the upper surface of the PCB board 2, the TEC cooler 4 includes: an upper ceramic substrate 410, a TEC cooling chip 420 and a lower ceramic substrate 430 sequentially distributed from top to bottom, the TEC cooling chip 420 is welded to the upper ceramic substrate 410, and the TEC cooling chip 420 is also welded to the lower ceramic substrate 430;
[0034] The upper ceramic substrate 410 in the TEC cooler 4 extends horizontally outward to the top of the heat insulation board 3 and is fixed to the heat insulation board 3. There is a gap between the lower surface of the lower ceramic substrate 430 in the TEC cooler 4 and the upper surface of the base 1 that is larger than the thickness tolerance of the TEC cooler 4, and the gap is filled with soft thermal conductive paste 10.
[0035] On the upper surface of the upper ceramic substrate 410 in the TEC cooler 4, a plurality of ceramic heat sinks 5 bonded with gold wires to the PCB board 2 are fixed in the area above the TEC cooling chip 420, and an EML chip 6 is fixed on each ceramic heat sink 5. On the upper surface of the upper ceramic substrate 410, an optical fiber array 7 coupled with all the EML chips 6 is fixed in the area above the heat insulation board 3. The optical fiber array 7 is preferably fixed on the upper surface of the upper ceramic substrate 410 by bonding;
[0036] By increasing the size of the upper ceramic substrate 410 and fixing the ceramic heat sink 5 and the optical fiber array 7 on the upper ceramic substrate 410 in the TEC cooler 4, it is possible to ensure that the error in the height direction between the EML chip 6 and the core of the optical fiber array 7 is small, effectively improving the coupling efficiency and significantly improving the yield;
[0037] By fixing the extended section of the upper ceramic substrate 410 to the heat insulation board 3, the TEC cooler 4 can be kept suspended, and a gap larger than the thickness tolerance of the TEC cooler 4 is formed between the lower surface of the lower ceramic substrate 430 in the TEC cooler 4 and the upper surface of the base 1, so only the thickness accuracy tolerance of the upper ceramic substrate 410 of ±10um needs to be considered, which is significantly smaller than the thickness tolerance of ±75um, thereby ensuring that the error in the height direction of the ceramic heat sink 5 and the PCB board 2 is small, so that the length of the high-frequency gold wire is shortened and the high-frequency performance is improved;
[0038] Since the ceramic heat sink 5 and the optical fiber array 7 are both fixed on the upper ceramic substrate 410 in the TEC cooler 4, when the 400G DR4 optical engine with enhanced optical path stability is working at high temperature, the EML chip 6 and the optical fiber array 7 are both on the cold side of the TEC cooler 4, the temperature difference between them is small, the deformation caused by temperature is small, and the optical path is more stable. When the 400G DR4 optical engine with enhanced optical path stability is working at low temperature, the EML chip 6 and the optical fiber array 7 are both on the hot side of the TEC cooler 4, the temperature difference between them is also small, the deformation caused by temperature is also small, and the optical path is more stable.
[0039] The TEC cooler 4 only increases the size of the upper ceramic substrate 410, but does not increase the number of TEC cooling chips 420. Therefore, compared with the TEC cooler 4 with a larger size and an increased number of TEC cooling chips 420, the cost can be effectively reduced while ensuring the structural stability of the TEC cooler 4, while the power consumption remains unchanged.
[0040] Example 2
[0041] like Figure 4 As shown, this embodiment is a further improvement on the basis of embodiment 1, and the details are as follows:
[0042] The gap height between the lower surface of the lower ceramic substrate 430 and the upper surface of the base 1 is 300um, which is much larger than the ±75um thickness tolerance of the TEC cooler 4 , thereby effectively absorbing the thickness tolerance of the TEC cooler 4 and facilitating the filling of the soft thermal paste 10 .
[0043] Example 3
[0044] like Figure 3 , Figure 4 As shown, this embodiment is a further improvement on the basis of Embodiment 1 or 2, and the details are as follows:
[0045] A lens 8 and an optical isolator 9 are coupled in sequence between each EML chip 6 and the optical fiber array 7 along the light propagation direction. The light emitted by each EML chip 6 is incident on the optical fiber array 7 after passing through a lens 8 and an optical isolator 9 in sequence. The lens 8 is fixed to the upper ceramic substrate 410 with ultraviolet glue. Since the error between the EML chip 6 and the optical fiber array 7 core in the height direction can be ensured to be small in this solution, the thickness tolerance of the ultraviolet glue under the lens 8 is also small, and the reliability is higher, so that the coupling efficiency and yield are improved. The optical isolator 9 is fixed on the light port side of the optical fiber array 7.
[0046] Furthermore: four ceramic heat sinks 5 are fixed on the upper surface of the upper ceramic substrate 410 along the width direction of the PCB board 2, and an EML chip 6 coupled to the optical fiber array 7 is fixed on each ceramic heat sink 5. The number of lenses 8 is four, the number of optical isolators 9 is four, and the optical fiber array 7 is a four-channel optical fiber array 7.
[0047] Example 4
[0048] like Figure 4 As shown, this embodiment is a further improvement on the basis of Embodiment 1, 2 or 3, and the details are as follows:
[0049] The thermal coefficient of the soft thermal conductive paste 10 is preferably greater than 10 W / mk. Even if the TEC cooler 4 is in a suspended state, the TEC cooler 4 can effectively conduct heat with the base 1 through the soft thermal conductive paste 10 .
[0050] Example 5
[0051] like Figure 4 As shown, this embodiment is a further improvement on any one of Embodiments 1 to 4, and the details are as follows:
[0052] The upper ceramic substrate 410 and the heat insulation board 3 are fixed to each other by bonding.
[0053] Example 6
[0054] like Figure 4 As shown, this embodiment is a further improvement on any one of Embodiments 1 to 5, and the details are as follows:
[0055] The material of the heat insulation board 3 is preferably quartz. The thermal conductivity of quartz is very low, only about 1 W / mk, and it can be used as a heat insulation board very well.
[0056] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in the field can change, modify, replace and modify the above embodiments within the scope of the present invention.
Claims
1. A 400G DR4 optical engine with enhanced optical path stability, comprising: A base (1) made of tungsten copper and a PCB (2) placed on the base (1), wherein a through hole (210) penetrating the upper and lower surfaces of the PCB (2) is provided in a partial area corresponding to the base (1), wherein a heat insulation board (3) fixed to the upper surface of the base (1) and lower than the upper surface of the PCB (2) is arranged in the through hole (210), wherein the heat insulation board (3) has a lower thermal conductivity than that of tungsten copper, and a TEC cooler (4) is suspended in the through hole (210) and is lower than the upper surface of the PCB (2), wherein an upper ceramic substrate (410) in the TEC cooler (4) extends horizontally outward to the top of the heat insulation board (3) and is in contact with the heat insulation board (3). The TEC cooler (4) is fixed to a heat insulation board (3); a gap greater than the thickness tolerance of the TEC cooler (4) is provided between the lower surface of the lower ceramic substrate (430) and the upper surface of the base (1); the gap is filled with a soft thermal conductive paste (10); a plurality of ceramic heat sinks (5) bonded to the PCB board (2) with gold wires are fixed on the upper surface of the upper ceramic substrate (410) in an area above the TEC cooling chip (420); an EML chip (6) is fixed on each ceramic heat sink (5); and an optical fiber array (7) coupled to all the EML chips (6) is fixed on the upper surface of the upper ceramic substrate (410) in an area above the heat insulation board (3).
2. The 400G DR4 optical engine with enhanced optical path stability according to claim 1, characterized in that: The gap height between the lower surface of the lower ceramic substrate (430) and the upper surface of the base (1) is 300 um.
3. The 400G DR4 optical engine with enhanced optical path stability according to claim 1, characterized in that: A lens (8) and an optical isolator (9) are sequentially coupled between each EML chip (6) and the optical fiber array (7) along the light propagation direction; the lens (8) is fixed to the upper ceramic substrate (410) using ultraviolet glue; and the optical isolator (9) is fixed to the optical port side of the optical fiber array (7).
4. The 400G DR4 optical engine with enhanced optical path stability according to claim 3, characterized in that: Four ceramic heat sinks (5) are fixed on the upper surface of the upper ceramic substrate (410) along the width direction of the PCB board (2), and an EML chip (6) coupled to the optical fiber array (7) is fixed on each ceramic heat sink (5). The number of the lenses (8) is four, the number of the optical isolators (9) is four, and the optical fiber array (7) is a four-channel optical fiber array.
5. The 400G DR4 optical engine with enhanced optical path stability according to claim 1, characterized in that: The thermal coefficient of the soft thermal conductive paste (10) is greater than 10 W / mk.
6. The 400G DR4 optical engine with enhanced optical path stability according to claim 1, characterized in that: The upper ceramic substrate (410) and the heat insulation board (3) are fixed to each other by bonding.
7. A 400GDR4 light engine with enhanced light path stability according to any one of claims 1 to 6, characterized in that: The material of the heat insulation board (3) is quartz.