Mini lens and 800g multimode optical module

Abstract

The present application relates to a kind of mini lenses, the lens body of less than 5.6mm, thickness less than 1.1mm, the lens body has the reflective surface of oblique distribution, the bottom surface and side surface of lens body respectively have first light surface and second light surface to the reflective surface.A kind of 800G multimode optical module, PCB board and mini lens, two mini MT are fixed on PCB board using glue bonding, each mini MT is fixed with mini lens, and the mini lens on mini MT is suspended relative to PCB board.Autumn effect is that mini MT is fixed on PCB board, and mini lens is attached to mini MT, so that mini lens is suspended relative to PCB board without contact, so that the stress of fiber bending in mini MT cannot cause the deviation of mini lens and mini MT, and the space of PCB board can be saved.

Description

Technical Field

[0001] This invention relates to the field of optical modules, specifically to a mini lens and an 800G multimode optical module. Background Technology

[0002] Traditional 800G multimode optical modules generally adopt an 8-channel optical solution, i.e., 8x100G (single-channel 100G). This includes a PCB board and DSP chips and lenses arranged sequentially along the optical path on the PCB board. Two sets of lenses are arranged front-to-back with identical structures to form a front-four and rear-four path configuration. Each lens has horizontally distributed MTs inserted into it. Furthermore, electrical chips (TIA chips and Driver chips) and optical chips (array detector chips and array transmitting optical chips) are arranged on the PCB board within the area covered by each lens. The optical chips have 4 transmitting channels and 4 receiving channels. The specific structure is as follows... Figure 1 and Figure 2 As shown.

[0003] This type of 800G multimode optical module has the following defects:

[0004] 1) In this scheme, the two lenses are distributed front and back. In order to avoid interference between the optical fiber of the front lens and the rear lens, the distance between the two lenses is relatively far. Since the lens is fixed on the PCB board and then the MT is fixed to the lens, if the distance is too close, the optical fiber in the MT will generate stress when it bends inside the module. The stress will cause the position of the MT and the lens to shift, resulting in a decrease in optical performance. If the rear lens is too far back and the optical fiber is not long enough, the excessive bending force of the optical fiber when the module is assembled into the shell will also cause the optical path of the MT on the rear lens to shift, resulting in a decrease in optical performance.

[0005] 2) Due to the excessive distance between the two lenses, there is a problem that the electrical chip under the rear lens is too far away from the DSP chip, which leads to excessive consumption of high-frequency signals on the PCB board and poor electrical performance.

[0006] 3) The existing solution is to bond the lens to the PCB board. The lens is made of PEI, and its coefficient of thermal expansion is much greater than that of the PCB board, which causes optical displacement at high and low temperatures (because the optical chip is attached to the PCB board, the lens will thermally expand and shift). Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a mini lens and an 800G multimode optical module to overcome the shortcomings of the prior art.

[0008] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: a mini lens, comprising: a lens body with a length of less than 5.6 mm and a thickness of less than 1.1 mm, the lens body having obliquely distributed reflective surfaces, and the bottom surface and the side surface of the lens body having a first light surface and a second light surface facing the reflective surfaces, respectively.

[0009] The advantages are: by designing the lens as a mini-type, it can be fixed on the mini-MT, and then the mini-MT can be fixed on the PCB board, so that the mini-lens is suspended, thus not occupying the space of the PCB board, and the stress of fiber bending in the mini-MT will not cause the mini-lens to shift from the mini-MT.

[0010] Based on the above technical solution, the present invention can be further improved as follows.

[0011] Furthermore, the side of the lens body opposite to the second optical surface extends outward to form a wedge shape. The upper surface of the wedge shape is the reflecting surface, and the lower surface of the wedge shape is the first optical surface. The lower surface of the wedge shape is higher than the bottom surface of the lens body.

[0012] Furthermore, the lens body has eight sequentially arranged first hemispherical protrusions on the first optical surface, and eight sequentially arranged second hemispherical protrusions on the second optical surface, with the eight first hemispherical protrusions and eight second hemispherical protrusions corresponding one-to-one.

[0013] Furthermore, the eight first hemisphere protrusions are arranged in two alternating groups of four; the eight second hemisphere protrusions are also arranged in two alternating groups of four.

[0014] Furthermore, the second optical surface of the lens body has at least one pair of guide pins.

[0015] The beneficial effects of adopting the above technical solution are as follows: a pair of guide pins can ensure that the mini lens and miniMT are aligned in the XY directions, while the mini lens and miniMT are directly attached in the Z direction.

[0016] Based on the above technical solution, the present invention also provides an 800G multimode optical module, including: a PCB board and a mini lens. Two mini MTs are glued and fixed on the PCB board. Each mini MT is fixed with a mini lens. The mini lens on the mini MT is suspended relative to the PCB board. A DSP chip is fixed on the PCB board. An optical chip is fixed on the PCB board below the first optical surface of each mini lens. An electrical chip is fixed on the PCB board between the DSP chip and the optical chip.

[0017] The beneficial effects are:

[0018] In traditional solutions, the lens is fixed to the PCB board, and then the MT is fixed to the lens. When the optical fiber in the MT bends inside the module, stress is generated. This stress causes the MT and the lens to shift, resulting in a decrease in optical performance. The fiber bends because the module length is limited. The optical fiber is usually made longer due to tolerances during production. This causes the fiber to bend when assembled into the module. In this solution, the mini MT is fixed to the PCB board, and the mini lens is attached to the mini MT, so that the mini lens is suspended relative to the PCB board and does not contact it. Therefore, the stress of the fiber bending in the mini MT will not cause the mini lens and the mini MT to shift. Moreover, this design can save PCB board space.

[0019] In addition, due to the small size of the designed mini lens, the electrical chip will not be covered by the mini lens at all. This allows the electrical chip to be directly soldered to the PCB board using SMT packaging technology, while the upper surface of the electrical chip can be directly contacted with the module shell for heat dissipation using thermally conductive adhesive, which greatly enhances the heat dissipation effect.

[0020] The mini MT is glued to the PCB board. Due to the small size of the mini MT and the fact that the thermal expansion coefficient of the MT is closer to that of the PCB, the thermal expansion has a smaller impact and the optical performance at high and low temperatures is more stable and better.

[0021] Furthermore, the electrical chip includes a TIA chip and a Driver chip, and the optical chip includes an array detector chip and an array transmitting light chip; the array detector chip corresponds to 4 channels of receiving light and the array detector chip corresponds to the TIA chip; the array transmitting light chip corresponds to 4 channels of transmitting light and the array transmitting light chip corresponds to the Driver chip.

[0022] Furthermore, the mini MT has a positioning hole, and the guide pin on the mini lens is inserted into the positioning hole and fixed with glue. The width of the mini lens outside the mini MT is less than 1.1mm.

[0023] Furthermore, the length of the mini MT is less than 6.4mm, two mini MTs are arranged side by side on the PCB board, two sets of optical chips are arranged side by side on the PCB board, and two sets of electrical chips are arranged side by side on the PCB board.

[0024] The further beneficial effects of adopting the above are as follows: This 800G multimode optical module can be used in QSFP-DD and Q112, OSFP packages. Conventionally, it can only be placed front and back. The advantages of placing it side by side are: the distance between the electrical chip and the DSP chip is shortened, the RF lines on the PCB board are also shortened, the RF performance is better, the RF loss is lower, and the power consumption is lower.

[0025] Furthermore, the mini lens is made of PE I with a coefficient of thermal expansion of 55ppm / ℃; the mini MT is made of PPS with a coefficient of thermal expansion of less than 20ppm / ℃; and the PCB board has a coefficient of thermal expansion of 11ppm / ℃.

[0026] The further beneficial effects of adopting the above are: the coefficient of thermal expansion of mini MT is smaller and closer to that of PCB board. In addition, the bonding length and width of mini MT to PCB board is smaller than that of conventional lens to PCB board. Therefore, the high and low temperature performance of mini MT bonding to PCB board in this solution is more stable. Attached Figure Description

[0027] Figure 1 This is a front view of a traditional 800G multimode optical module.

[0028] Figure 2 A top view of a traditional 800G multimode optical module;

[0029] Figure 3 This is a three-dimensional view of the mini lens in this invention;

[0030] Figure 4 This is a bottom view of the mini lens in this invention;

[0031] Figure 5 This is a side view of the mini lens in this invention;

[0032] Figure 6 This is a top view of the 800G multimode optical module in this invention;

[0033] Figure 7 This is a front view of the 800G multimode optical module in this invention;

[0034] Figure 8 This is a top view of part of the structure of the 800G multimode optical module in this invention.

[0035] The attached diagram lists the components represented by each number as follows:

[0036] 1. Mini lens, 110. Lens body, 120. Reflecting surface, 130. First optical surface, 140. Second optical surface, 150. Wedge shape, 160. First hemispherical protrusion, 170. Second hemispherical protrusion, 180. Guide pin, 2. PCB board, 3. Mini MT, 4. DSP chip, 5. Optical chip, 6. Electrical chip. Detailed Implementation

[0037] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0038] Example 1

[0039] like Figure 3 , Figure 4 , Figure 5 As shown, a mini lens includes: a lens body 110, wherein the lens body 110 has dimensions of less than 5.6 mm in length and less than 1.1 mm in thickness; the lens body 110 has obliquely distributed reflective surfaces 120; the bottom surface of the lens body 110 has a first light surface 130 facing the reflective surface 120; and the side surface of the lens body 110 has a second light surface 140 facing the reflective surface 120. Emitted light can be incident on the reflective surface 120 via the first light surface 130 and reflected by the reflective surface 120 to the second light surface 140, and finally exited via the second light surface 140. Received light can be incident on the reflective surface 120 via the second light surface 140 and reflected by the reflective surface 120 to the first light surface 130, and finally exited via the first light surface 130. That is, the first light surface 130 can be used for both incident and received light, and the second light surface 140 can be used for both incident and received light.

[0040] The lens is designed as a mini i type. When it is applied in an 800G multimode optical module, it can be fixed on the mini i MT3 which is fixed to the PCB board 2, so that the mini i lens 1 is suspended and does not occupy the space of the PCB board 2. Furthermore, the stress of fiber bending in the mini i MT3 will not cause the mini i lens 1 to shift from the mini i MT3.

[0041] Example 2

[0042] like Figure 3 , Figure 5 As shown, this embodiment is a further improvement on embodiment 1, as detailed below:

[0043] The side of the lens body 110 opposite to the second light surface 140 extends outward to form a wedge 150. The upper surface of the wedge 150 is the reflective surface 120, and the lower surface of the wedge 150 is the first light surface 130. The lower surface of the wedge 150 is higher than the bottom surface of the lens body 110, and the first light surface 130 of the wedge 150 is suspended so as to be matched with the optical chip 5 later.

[0044] Example 3

[0045] like Figure 3 , Figure 4 , Figure 5 As shown, this embodiment is a further improvement on embodiment 2, as detailed below:

[0046] The lens body 110 has eight first hemispherical protrusions 160 arranged in sequence on the first optical surface 130, and eight second hemispherical protrusions 170 arranged in sequence on the second optical surface 140. The eight first hemispherical protrusions 160 and the eight second hemispherical protrusions 170 correspond one-to-one.

[0047] Furthermore: the eight first hemisphere protrusions 160 are arranged in two alternating groups of four, with the four first hemisphere protrusions 160 in one group corresponding to four transmitted light beams and the four first hemisphere protrusions 160 in the other group corresponding to four received light beams; the eight second hemisphere protrusions 170 are arranged in two alternating groups of four, with the four second hemisphere protrusions 170 in one group corresponding to four transmitted light beams and the four second hemisphere protrusions 170 in the other group corresponding to four received light beams.

[0048] Example 4

[0049] like Figure 3 , Figure 4 , Figure 5 As shown, this embodiment is a further improvement on embodiment 1, 2, or 3, as detailed below:

[0050] The second optical surface 140 of the lens body 110 has at least one pair of guide pins 180, that is, at least two guide pins 180. The guide pins 180 can be used to connect and fix the mini lens 1 and the mini MT3, and ensure that the mini lens 1 and the mini MT3 are aligned in the X and Y directions, while the mini lens 1 and the mini MT3 are directly attached in the Z direction.

[0051] Example 5

[0052] like Figure 6 , Figure 7 , Figure 8 As shown, an 800G multimode optical module includes: a PCB board 2 and a mini lens 1. Two mini MT3s are glued and fixed on the PCB board 2. Since the thickness of the mini lens 1 is less than 1.1mm, the thickness of the mini MT3 can be 1.25mm. The mini lens 1 is thinner than the mini MT3. Each mini MT3 is fixed with a mini lens 1. The mini lens 1 on the mini MT3 is suspended relative to the PCB board 2.

[0053] A DSP chip 4 is fixed on the PCB board 2. In addition, an optical chip 5 is fixed below the first light surface 130 of each mini lens 1 on the PCB board 2. An electrical chip 6 is fixed between the DSP chip 4 and the optical chip 5 on the PCB board 2. Since this solution is an 800G optical module, it has 8 transmission channels and 8 reception channels, that is, the optical chip 5 below the first light surface 130 of each mini lens 1 has 4 transmission channels and 4 reception channels.

[0054] In the traditional solution, the lens is fixed on the PCB board, and then the MT is fixed to the lens. When the optical fiber in the MT bends inside the module, stress will be generated. This stress will cause the MT and the lens to shift, resulting in a decrease in optical performance. The fiber bends because the module length is limited. The optical fiber is usually made longer due to tolerances during production. Thus, the optical fiber will bend when assembled into the module. In this solution, the mini MT3 is fixed on the PCB board 2, and the mini lens 1 is attached to the mini MT3, so that the mini lens 1 is suspended relative to the PCB board 2 and does not contact it. Therefore, the stress of the fiber bending in the mini MT will not cause the mini lens 1 and mini MT3 to shift. Moreover, this design can save space on the PCB board 2.

[0055] In addition, because the mini lens 1 is small in size, the electrical chip 6 will not be covered by the mini lens 1 at all. In this way, the electrical chip 6 can be directly soldered to the PCB board 2 using the SMT packaging process, and the upper surface of the electrical chip 6 can be directly contacted with the module shell for heat dissipation using thermal conductive adhesive, which greatly enhances the heat dissipation effect.

[0056] The mini MT3 is glued to the PCB board 2. Due to its small size, the mini MT3 is less affected by thermal expansion and has better high and low optical performance.

[0057] Furthermore: Electrical chip 6 typically includes a TIA chip and a Driver chip, while optical chip 5 includes an array detector chip and an array transmitting light chip. The array detector chip corresponds to 4 channels of receiving light and is equivalent to the TIA chip, while the array transmitting light chip corresponds to 4 channels of transmitting light and is equivalent to the Driver chip.

[0058] The emitted light from the array emitting light chip can be directed through the first light surface 130 to the reflecting surface 120, and then reflected by the reflecting surface 120 to the second light surface 140. Finally, it exits through the second light surface 140 and enters the optical fiber inside the mini MT3. The received light in the optical fiber inside the mini MT3 can be directed through the second light surface 140 to the reflecting surface 120, and then reflected by the reflecting surface 120 to the first light surface 130. Finally, it exits through the first light surface 130 and enters the array detector chip.

[0059] Example 6

[0060] like Figure 6 , Figure 7 As shown, this embodiment is a further improvement on embodiment 5, as detailed below:

[0061] The mini MT3 has a positioning hole. The guide pin 180 on the mini lens 1 is inserted into the positioning hole and fixed with glue, which can make the mini lens 1 and mini MT3 stably fixed. The width of the mini lens 1 outside the mini MT3 is less than 1.1mm.

[0062] Example 7

[0063] like Figure 6 As shown, this embodiment is a further improvement on embodiment 5, as detailed below:

[0064] The length of mini lens 1 is less than 5.6mm, and the length of mini MT3 is less than 6.4mm. Therefore, two mini MT3s can be arranged side by side on PCB board 2, two sets of optical chips 5 can also be arranged side by side on PCB board 2, and two sets of electrical chips 6 can also be arranged side by side on PCB board 2. Thus, this 800G multimode optical module can be used for QSFP-DD and Q112, OSFP packages. Conventionally, they can only be placed one in front of the other. The advantages of side-by-side placement are: the distance between electrical chip 6 and DSP chip 4 is shortened, the RF line of PCB board 2 is also shortened, the RF performance is better, the RF loss is lower, and the power consumption is lower.

[0065] Example 8

[0066] like Figure 6 , Figure 7 , Figure 8 As shown, this embodiment is a further improvement on embodiment 5, 6, or 7, as detailed below:

[0067] The mini lens 1 is made of PE I with a coefficient of thermal expansion of 55ppm / ℃; the mini MT3 is made of PPS with a coefficient of thermal expansion of less than 20ppm / ℃; the PCB board 2 has a coefficient of thermal expansion of 11ppm / ℃. The mini MT3 has a smaller coefficient of thermal expansion and is closer to the coefficient of thermal expansion of the PCB board 2. In addition, the bonding length and width between the mini MT3 and the PCB board 2 are smaller than the bonding dimensions of conventional lenses and the PCB board 2. Therefore, this solution uses mini MT3 to bond the PCB board 2, resulting in more stable high and low temperature performance.

[0068] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. An 800G multimode optical module, characterized in that, include: The mini lens (1) and PCB board (2) are used to attach two mini MTs (3) to the PCB board (2) with glue. The two mini MTs (3) are arranged side by side on the PCB board (2). Each mini MT (3) is fixed with a mini lens (1). The mini lens (1) includes a lens body (110) with a length less than 5.6 mm and a thickness less than 1.1 mm. The lens body (110) has a reflective surface (120) with an oblique distribution. The bottom surface and the side surface of the lens body (110) have a first light surface (130) and a second light surface (140) facing the reflective surface (120), respectively. The length of the mini MT (3) is less than 6.4 mm. The mini lens (1) on the MT (3) is suspended relative to the PCB board (2). The PCB board (2) is fixed with a DSP chip (4). The PCB board (2) is fixed with an optical chip (5) below the first light surface (130) of each mini lens (1). The PCB board (2) is fixed with an electrical chip (6) between the DSP chip (4) and the optical chip (5).

2. The 800G multimode optical module according to claim 1, characterized in that: The side of the lens body (110) opposite to the second light surface (140) extends outward to form a wedge (150). The upper surface of the wedge (150) is a reflecting surface (120), and the lower surface of the wedge (150) is a first light surface (130). The lower surface of the wedge (150) is higher than the bottom surface of the lens body (110).

3. An 800G multimode optical module according to claim 2, characterized in that: The lens body (110) has eight first hemispherical protrusions (160) arranged in sequence on the first optical surface (130), and the lens body (110) has eight second hemispherical protrusions (170) arranged in sequence on the second optical surface (140). The eight first hemispherical protrusions (160) and the eight second hemispherical protrusions (170) correspond one-to-one.

4. An 800G multimode optical module according to claim 3, characterized in that: The eight first hemisphere protrusions (160) are arranged in two alternating groups of four; the eight second hemisphere protrusions (170) are arranged in two alternating groups of four.

5. An 800G multimode optical module according to any one of claims 1 to 4, characterized in that: The lens body (110) has at least one pair of guide pins (180) on its second optical surface (140).

6. An 800G multimode optical module according to claim 1, characterized in that, The electrical chip (6) includes a TIA chip and a Driver chip, and the optical chip (5) includes an array detector chip and an array emitting light chip; the array detector chip corresponds to 4 channels of receiving light, and the array detector chip corresponds to the TIA chip; the array emitting light chip corresponds to 4 channels of emitting light, and the array emitting light chip corresponds to the Driver chip.

7. An 800G multimode optical module according to claim 5, characterized in that, The mini MT (3) has a positioning hole, and the guide pin (180) on the mini lens (1) is inserted into the positioning hole and fixed with glue. The width of the mini lens (1) outside the mini MT (3) is less than 1.1 mm.

8. An 800G multimode optical module according to claim 1, characterized in that, Two sets of optical chips (5) are arranged side by side on the PCB board (2), and two sets of electrical chips (6) are arranged side by side on the PCB board (2).

9. An 800G multimode optical module according to any one of claims 1 or 6 to 8, characterized in that, The mini lens (1) is made of PEI with a thermal expansion coefficient of 55ppm / ℃; the mini MT (3) is made of PPS with a thermal expansion coefficient of less than 20ppm / ℃; and the PCB board (2) has a thermal expansion coefficient of 11ppm / ℃.

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