400G DR4 optical engine

Abstract

The utility model relates to a 400G DR4 optical engine which is characterized in that a base made of tungsten copper is adopted, a TEC refrigerator lower than the upper surface of a PCB and a base plate are arranged in a through hole in the PCB, the base plate is fixed to the upper surface of the base, an upper ceramic substrate in the TEC refrigerator is fixed to the side face of the base plate, and a lower ceramic substrate in the TEC refrigerator is fixed to the side face of the base plate. A gap larger than the thickness tolerance of the TEC refrigerator is reserved between the lower surface of a lower ceramic substrate in the TEC refrigerator and the upper surface of a base, and the gap is filled with soft heat conduction paste. An optical fiber array is fixed on the backing plate, a plurality of ceramic heat sinks bonded with the PCB through gold wires are fixed on the upper ceramic substrate, and an EML chip coupled with the optical fiber array is fixed on each ceramic heat sink. The beneficial effects are that the thickness tolerance of + / -75 [mu] m of the TEC refrigerator can be effectively absorbed, the coupling efficiency of the EML chip and the optical fiber array is effectively improved, the yield is greatly improved, the length of the high-frequency gold wire between the ceramic heat sink and the PCB is shortened, and the high-frequency performance is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of optical engines, and in particular to a 400G DR4 optical engine. 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 which are lower than the upper surface of the PCB board and fixed to the upper surface of the base are arranged in the through hole, the TEC cooler is bonded with gold wires to the PCB board, a plurality of ceramic heat sinks bonded with gold wires to the PCB board are fixed on the TEC cooler, an EML chip coupled with 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 by 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 plate and an upper aluminum nitride ceramic pad and a lower aluminum nitride ceramic pad located above and below the TEC cooling plate. The electrode of the TEC cooler is located on the lower aluminum nitride ceramic pad, which usually has a thickness tolerance of ±75um. The thickness tolerance is generated when the upper aluminum nitride ceramic pad + TEC cooling plate + lower aluminum nitride ceramic pad are welded and fixed. Since the TEC cooler and the optical fiber array are fixed on the same upper surface of the base, the height error between the EML chip and the 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 present invention is to provide a 400G DR4 optical engine to overcome the deficiencies in the above-mentioned prior art.

[0008] The utility model provides a technical solution to the above technical problems as follows: a 400G DR4 optical engine, 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 TEC cooler and a pad lower than the upper surface of the PCB board are arranged in the through hole, the pad is fixed to the upper surface of the base, an upper ceramic substrate in the TEC cooler is fixed to the side of the pad, the upper surface of the upper ceramic substrate is flush with the upper surface of the pad, a gap larger than the thickness tolerance of the TEC cooler is reserved between the lower surface of the lower ceramic substrate in the TEC cooler and the upper surface of the base, and soft thermal conductive paste is filled in the gap; an optical fiber array is fixed on the pad, 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 upper ceramic substrate, and an EML chip coupled to the optical fiber array is fixed on each ceramic heat sink.

[0009] The beneficial effects of the utility model are:

[0010] By fixing the upper ceramic substrate in the TEC cooler to the side of the pad, and the upper surface of the upper ceramic substrate is flush with the upper surface of the pad, and a gap larger than the thickness tolerance of the TEC cooler is reserved between the lower surface of the lower ceramic substrate in the TEC cooler and the upper surface of the base, the ±75um thickness tolerance of the TEC cooler can be effectively absorbed to overcome the influence of the thickness tolerance of the TEC cooler, ensure that the error in the height direction of the EML chip and the fiber array core is small, effectively improve the coupling efficiency and greatly improve the yield, and ensure that the error in the height direction of the ceramic heat sink and the PCB board is small, so that the length of the high-frequency gold wire is shortened and the high-frequency performance is improved.

[0011] On the basis of the above technical solution, the present invention can also be improved as follows.

[0012] Furthermore, a gap of 300 um is reserved between the lower surface of the lower ceramic substrate and the upper surface of the base in the TEC cooler.

[0013] 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.

[0014] Furthermore, a lens and an optical isolator are coupled in sequence in the through hole between each EML chip and the optical fiber array along the light propagation direction. The lens is fixed to the upper ceramic substrate by using ultraviolet glue, and the optical isolator is fixed on the light port side of the optical fiber array. The thermal conductivity of the pad is lower than that of tungsten copper.

[0015] The further beneficial effects of adopting the above method are as follows: since the present solution effectively absorbs the ±75um thickness tolerance of the TEC cooler to 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;

[0016] Since the thermal conductivity of the pad is lower than that of tungsten copper, the pad can be used as an insulation board to reduce the heat conduction between the base and the fiber array. When the 400G DR4 optical engine is working at high temperature, the EML chip, lens, and fiber array will be located on the cold side of the TEC cooler. The temperature difference between the three is small, the deformation caused by temperature is small, and the optical path is more stable. When the 400G DR4 optical engine is working at low temperature, the EML chip, lens, and fiber array will be located on the hot side of the TEC cooler. The temperature difference between the three is also small, the deformation caused by temperature is also small, and the optical path is more stable.

[0017] Furthermore, the material of the backing plate is quartz.

[0018] 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.

[0019] Furthermore, one end of the upper ceramic substrate close to the pad is extended toward the pad by a predetermined distance and then bonded to the side surface of the pad.

[0020] Furthermore, one end of the upper ceramic substrate bonded to the pad is bent downward along the side of the pad, and the bending length does not exceed the lower surface of the lower ceramic substrate.

[0021] A further beneficial effect of the above method is that the upper ceramic substrate can increase its contact area with the pad by bending downward, thereby ensuring the stability of the connection between the two.

[0022] Furthermore, the thermal coefficient of the soft thermal paste is greater than 10 W / mk. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a top view of a 400G DR4 optical engine in the prior art;

[0024] Figure 2 This is a main view of a 400G DR4 optical engine in the prior art;

[0025] Figure 3 A top view of the 400G DR4 optical engine in the present invention;

[0026] Figure 4 This is a front view of the 400G DR4 optical engine in the present invention.

[0027] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0028] 1. Base, 2. PCB board, 210, through hole, 3. TEC cooler, 310, upper ceramic substrate, 320, lower ceramic substrate, 4. Pad, 5. Soft thermal paste, 6. Optical fiber array, 7. Ceramic heat sink, 8. EML chip, 9. Lens, 10. Optical isolator. DETAILED DESCRIPTION

[0029] 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.

[0030] Example 1

[0031] like Figure 3 , Figure 4 As shown, a 400G DR4 optical engine comprises: a base 1 and a PCB board 2, wherein the base 1 is made of tungsten copper, and the PCB board 2 is placed on the base 1, and a through hole 210 penetrating the upper and lower surfaces of the PCB board 2 is provided in a part of the area corresponding to the base 1, a TEC cooler 3 and a pad 4 lower than the upper surface of the PCB board 2 are arranged in the through hole 210, the pad 4 is fixed to the upper surface of the base 1, an upper ceramic substrate 310 in the TEC cooler 3 is fixed to the side of the pad 4, and the upper surface of the upper ceramic substrate 310 is flush with the upper surface of the pad 4, and a gap larger than the thickness tolerance of the TEC cooler 3 is reserved between the lower surface of the lower ceramic substrate 320 in the TEC cooler 3 and the upper surface of the base 1, and the gap is filled with soft thermal conductive paste 5;

[0032] The optical fiber array 6 is fixed on the backing plate 4, the TEC cooler 3 is bonded to the PCB board 2 with gold wires, a plurality of ceramic heat sinks 7 bonded to the PCB board 2 with gold wires are fixed on the upper ceramic substrate 310, and an EML chip 8 coupled to the optical fiber array 6 is fixed on each ceramic heat sink 7;

[0033] By fixing the upper ceramic substrate 310 in the TEC cooler 3 to the side of the pad 4, and the upper surface of the upper ceramic substrate 310 is flush with the upper surface of the pad 4, and a gap larger than the thickness tolerance of the TEC cooler 3 is reserved between the lower surface of the lower ceramic substrate 320 in the TEC cooler 3 and the upper surface of the base 1, the ±75um thickness tolerance of the TEC cooler 3 can be effectively absorbed to overcome the influence of the thickness tolerance of the TEC cooler 3, ensure that the error in the height direction of the EML chip 8 and the fiber core of the optical fiber array 6 is small, effectively improve the coupling efficiency and greatly improve the yield, and ensure that the error in the height direction of the ceramic heat sink 7 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.

[0034] Example 2

[0035] like Figure 4 As shown, this embodiment is a further improvement on the basis of embodiment 1, and the details are as follows:

[0036] The gap reserved between the lower surface of the lower ceramic substrate 320 in the TEC cooler 3 and the upper surface of the base 1 is 300um, which is much larger than the ±75um thickness tolerance of the TEC cooler 3, thereby effectively absorbing the thickness tolerance of the TEC cooler 3 and facilitating the filling of the soft thermal paste 5.

[0037] Example 3

[0038] 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:

[0039] In the through hole 210, a lens 9 and an optical isolator 10 are coupled in sequence between each EML chip 8 and the optical fiber array 6 along the light propagation direction. The light emitted by each EML chip 8 is incident on the optical fiber array 6 after passing through a lens 9 and an optical isolator 10 in sequence. The lens 9 is fixed to the upper ceramic substrate 310 by ultraviolet glue. Since the ±75um thickness tolerance of the TEC cooler 3 is effectively absorbed in this solution to ensure that the error between the EML chip 8 and the optical fiber array 6 core in the height direction is small, the thickness tolerance of the ultraviolet glue under the lens 9 is small, the reliability is higher, and the coupling efficiency and yield are improved. The optical isolator 10 is fixed on the optical port side of the optical fiber array 6;

[0040] The thermal conductivity of the pad 4 is lower than that of tungsten copper. Since the thermal conductivity of the pad 4 is lower than that of tungsten copper, the pad 4 can be used as a heat insulation board to reduce the heat conduction between the base 1 and the optical fiber array 6.

[0041] When the 400G DR4 optical engine is working at high temperature, the EML chip 8, lens 9, and optical fiber array 6 are all located on the cold surface of the TEC cooler 3. The temperature difference between the three is small, the deformation caused by temperature is small, and the optical path is more stable.

[0042] When the 400G DR4 optical engine is working at low temperature, the EML chip 8, lens 9, and optical fiber array 6 are all located on the hot surface of the TEC cooler 3. The temperature difference among them is small, the deformation caused by temperature is also small, and the optical path is more stable.

[0043] Example 4

[0044] like Figure 3 , Figure 4 As shown, this embodiment is a further improvement on the basis of embodiment 3, and the details are as follows:

[0045] The material of the backing plate 4 is preferably quartz, which has a very low thermal conductivity of only ~1 W / mk and can be used as a heat insulation plate.

[0046] Example 5

[0047] like Figure 4 As shown, this embodiment is a further improvement on the basis of embodiment 3, and the details are as follows:

[0048] One end of the upper ceramic substrate 310 close to the pad 4 extends toward the pad 4 for a predetermined distance and then adheres to the side of the pad 4. In addition, one end of the upper ceramic substrate 310 that is adhered to the pad 4 is bent downward along the side of the pad 4, and the length of the bend does not exceed the lower surface of the lower ceramic substrate 320, that is, the upper ceramic substrate 310 is L-shaped. By bending downward, the upper ceramic substrate 310 can increase its contact area with the pad 4 to ensure the stability of the connection between the two.

[0049] Example 6

[0050] 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:

[0051] The thermal coefficient of the soft thermally conductive paste 5 is preferably greater than 10 W / mk, which can effectively achieve heat conduction.

[0052] 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, 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 TEC cooler (3) and a pad (4) lower than the upper surface of the PCB (2) are arranged in the through hole (210), wherein the pad (4) is fixed to the upper surface of the base (1), an upper ceramic substrate (310) in the TEC cooler (3) is fixed to the side of the pad (4), and the upper surface of the upper ceramic substrate (310) is fixed to the pad The upper surface of the TEC cooler (4) is flush with that of the base (1); a gap larger than the thickness tolerance of the TEC cooler (3) is reserved between the lower surface of the lower ceramic substrate (320) in the TEC cooler (3) and the upper surface of the base (1); the gap is filled with soft thermal conductive paste (5); an optical fiber array (6) is fixed on the pad (4); the TEC cooler (3) is gold-wire bonded to the PCB board (2); a plurality of ceramic heat sinks (7) gold-wire bonded to the PCB board (2) are fixed on the upper ceramic substrate (310); and an EML chip (8) coupled to the optical fiber array (6) is fixed on each ceramic heat sink (7).

2. The 400G DR4 optical engine according to claim 1, characterized in that: The gap reserved between the lower surface of the lower ceramic substrate (320) in the TEC cooler (3) and the upper surface of the base (1) is 300 um.

3. The 400G DR4 optical engine according to claim 1, characterized in that: A lens (9) and an optical isolator (10) are sequentially coupled in the through hole (210) between each EML chip (8) and the optical fiber array (6) along the light propagation direction; the lens (9) is fixed to the upper ceramic substrate (310) by using ultraviolet glue; the optical isolator (10) is fixed to the optical port side of the optical fiber array (6); and the thermal conductivity of the pad (4) is lower than that of tungsten copper.

4. The 400G DR4 optical engine according to claim 3, characterized in that: The material of the pad (4) is quartz.

5. The 400G DR4 optical engine according to claim 1, characterized in that: One end of the upper ceramic substrate (310) close to the pad (4) extends toward the pad (4) by a predetermined distance and then adheres to the side surface of the pad (4).

6. The 400G DR4 optical engine according to claim 5, characterized in that: One end of the upper ceramic substrate (310) bonded to the backing plate (4) is bent downwardly along the side of the backing plate (4), and the length of the bend does not exceed the lower surface of the lower ceramic substrate (320).

7. A 400G DR4 optical engine according to any one of claims 1 to 6, characterized in that: The thermal coefficient of the soft thermal conductive paste (5) is greater than 10 W / mk.

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