800G DR8 silicon optical module
By using a ceramic substrate and ceramic block structure in the 800G DR8 silicon photonics module, the problem of optical performance degradation caused by PCB thermal expansion was solved, and optical performance stability was achieved.
Patent Information
- Application Number
- CN202520232414.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-13
- Publication Date
- 2025-12-30
- Estimated Expiration
- 2035-02-13
AI Technical Summary
In traditional 800G DR8 silicon photonics modules, the PCB board has a large coefficient of thermal expansion, which makes the RX fiber array and array PD chip prone to displacement, affecting optical performance.
A ceramic substrate is used to replace part of the PCB board. The RX fiber array and array PD chip are fixed on the ceramic substrate and bonded to the TIA chip with gold wire through the ceramic block to ensure that the RX fiber array and array PD chip are on the same plane, avoiding displacement caused by PCB board deformation.
By using a ceramic substrate with a low coefficient of thermal expansion, the optical performance between the RX fiber array and the array PD chip is kept stable, avoiding performance degradation caused by PCB board deformation.
Smart Images
Figure CN223742798U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of silicon photonics module technology, specifically to an 800G DR8 silicon photonics module. Background Technology
[0002] A traditional 800G DR8 silicon photonics module includes one optical transmitter and two optical receivers. The transmitter and receivers are arranged side-by-side along the width of the PCB, with the receivers located on either side of the transmitter. Specifically... Figure 1 As shown, each optical receiver includes an RX fiber array, an array PD chip, and a TIA chip. The RX fiber array, array PD chip, and TIA chip are all four-channel. The RX fiber array is directly bonded to the PCB board, the array PD chip is fixed to the PCB board, the RX fiber array is coupled to the array PD chip, and the TIA chip is gold wire bonded to the array PD chip and the PCB board. Since the PCB board is made of epoxy resin fiberglass board, its thermal expansion coefficient is large, and it is easy to deform when it is installed in the housing. When the PCB board deforms, it will easily cause the RX fiber array and array PD chip to shift, thereby causing a decrease in optical performance. Utility Model Content
[0003] The technical problem to be solved by this utility model is to provide an 800G DR8 silicon photonics module to overcome the shortcomings of the prior art.
[0004] The technical solution of this utility model to solve the above-mentioned technical problems is as follows:
[0005] An 800G DR8 silicon photonics module includes: a PCB board, two ceramic substrates fixed side-by-side along its width direction on the PCB board, an RX fiber array fixed on the upper surface of each ceramic substrate, an array PD chip coupled to the RX fiber array on the upper surface of each ceramic substrate, two ceramic blocks of the same height as the ceramic substrates fixed side-by-side along its width direction on the PCB board, a T IA chip fixed on the upper surface of each ceramic block, the T IA chip being gold wire bonded to the array PD chip, and the T IA chip being gold wire bonded to the PCB board.
[0006] The beneficial effects of this invention are: the ceramic substrate has a small coefficient of thermal expansion and is not easily deformed; and since the RX fiber array and the array PD chip are on the same ceramic substrate, even if the PCB board is deformed, the RX fiber array and the array PD chip are still on the same plane, thereby ensuring that the optical performance between the RX fiber array and the array PD chip remains unchanged.
[0007] Based on the above technical solution, the present invention can be further improved as follows.
[0008] Furthermore, the thickness of the ceramic substrate is 0.2 mm to 0.4 mm.
[0009] The further beneficial effects of adopting the above are: if the ceramic substrate is too thin, it will be easily broken; if it is too thick, the length of the gold wire between the TIA chip and the PCB board will be too long, resulting in a decrease in high-frequency performance. Therefore, 0.2mm to 0.4mm is selected.
[0010] Furthermore, the thickness of the ceramic substrate is 0.25 mm.
[0011] Furthermore, gold is plated on the ceramic block, and the ceramic block is bonded to the GND pad of the PCB board using conductive silver paste. The TIA chip is electrically connected to the GND pad of the PCB board through the gold plating layer on the ceramic block and the conductive silver paste.
[0012] The further beneficial effect of adopting the above is that the gold wire from the TIA chip to the PCB board has a high-speed reference GND, and even if the gold wire is long, it will not cause excessive degradation of high-speed RF performance.
[0013] Furthermore, the ceramic substrate is made of aluminum nitride.
[0014] Furthermore, the RX fiber array and the array PD chip are respectively bonded and fixed on the ceramic substrate. Attached Figure Description
[0015] Figure 1 This is a structural diagram of an 800G DR8 silicon photonics module in the prior art;
[0016] Figure 2 This is a structural diagram of the 800G DR8 silicon photonics module in this utility model;
[0017] Figure 3 This is a partial side view of the 800G DR8 silicon photonics module of this utility model.
[0018] The attached diagram lists the components represented by each number as follows:
[0019] 1. PCB board, 2. Ceramic substrate, 3. RX fiber array, 4. Array PD chip, 5. Ceramic block, 6. TIA chip. Detailed Implementation
[0020] The principles and features of this utility model are described below with reference to the accompanying drawings. The examples given are only for explaining this utility model and are not intended to limit the scope of this utility model.
[0021] Example 1
[0022] like Figure 2 , Figure 3As shown, an 800G DR8 silicon photonics module includes: a PCB board 1, in this embodiment, the PCB board 1 is still an epoxy resin fiberglass board, that is, consistent with the prior art. Two ceramic substrates 2 are fixed side by side along the width direction of the PCB board 1. The two ceramic substrates 2 are respectively located on both sides of the light emitting end. The structure and fixing position of the light emitting end have not changed from the prior art, so they will not be described in detail here. An RX fiber array 3 is fixed on the upper surface of each ceramic substrate 2. An array PD chip 4 coupled to the RX fiber array 3 on the upper surface of each ceramic substrate 2 is fixed on the upper surface of each ceramic substrate 2. In addition, two ceramic blocks 5 of the same height as the ceramic substrate 2 are fixed side by side along the width direction of the PCB board 1. The two ceramic blocks 5 are respectively located on both sides of the light emitting end. A TIA chip 6 is fixed on the upper surface of each ceramic block 5. In this embodiment, the RX fiber array 3, the array PD chip 4 and the TIA chip 6 are still four-channel, that is, consistent with the prior art. The IA chip 6 is bonded to the array PD chip 4 with gold wires. The ceramic block 5 is at the same height as the ceramic substrate 2. The purpose is to ensure that the array PD chip 4 and the T IA chip 6 are at the same height, so as to minimize the length of the gold wires. The T IA chip 6 is bonded to the PCB board 1 with gold wires.
[0023] In this invention, the ceramic substrate 2 has a small coefficient of thermal expansion and is not easily deformed. Since the RX fiber array 3 and the array PD chip 4 are located on the same ceramic substrate 2, even if the PCB board 1 is deformed, the RX fiber array 3 and the array PD chip 4 will still be on the same plane, thereby ensuring that the optical performance between the RX fiber array 3 and the array PD chip 4 remains unchanged.
[0024] Example 2
[0025] like Figure 2 , Figure 3 As shown, this embodiment is a further improvement on embodiment 1, as detailed below:
[0026] The thickness of the ceramic substrate 2 is 0.2mm to 0.4mm. If the ceramic substrate 2 is too thin, it will be easily broken. If it is too thick, the gold wire between the TIA chip 6 and the PCB board 1 will be too long, resulting in a decrease in high-frequency performance. Therefore, 0.2mm to 0.4mm is selected.
[0027] Furthermore, the typical thickness of the ceramic substrate 2 is 0.25 mm.
[0028] Example 3
[0029] like Figure 2 , Figure 3 As shown, this embodiment is a further improvement on embodiment 1 or 2, as detailed below:
[0030] The ceramic block 5 is gold-plated. The ceramic block 5 can be gold-plated on all sides, or at least on the top surface, the bottom surface, and one side. The gold plating layer on the side is connected to the gold plating layers on the top and bottom surfaces, respectively. The gold plating can be achieved by chemical gold plating, which is low cost. The ceramic block 5 is bonded to the GND pad of the PCB board 1 with conductive silver paste. The TIA chip 6 is electrically connected to the GND pad of the PCB board 1 through the gold plating layer on the ceramic block 5 and the conductive silver paste. Therefore, the side of the ceramic block 5 can serve as a reference ground for the gold wire from the TIA chip 6 to the PCB board 1. With a reference ground, the high-speed RF noise is low, the anti-interference ability is improved, the impedance matching is better, etc., so even if the gold wire is long, it will not cause a significant decrease in high-speed RF performance.
[0031] Example 4
[0032] like Figure 2 , Figure 3 As shown, this embodiment is a further improvement on embodiment 1, 2, or 3, as detailed below:
[0033] The ceramic substrate 2 is preferably made of aluminum nitride. Of course, other materials are not excluded. This is just one example. Aluminum nitride ceramic has a small coefficient of thermal expansion and is not easily deformed. Therefore, even if the PCB board 1 is deformed, the optical performance between the RX fiber array 3 and the array PD chip 4 can be guaranteed to remain unchanged.
[0034] Example 5
[0035] like Figure 2 , Figure 3 As shown, this embodiment is a further improvement on any one of embodiments 1 to 4, as detailed below:
[0036] The RX fiber array 3 is fixed to the ceramic substrate 2 by adhesive bonding, and the array PD chip 4 is fixed to the ceramic substrate 2 by adhesive bonding. This is just a conventional processing method listed here, and other methods are not excluded.
[0037] 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 DR8 silicon photonic module, comprising: The application relates to a PCB board (1) which is provided with two ceramic substrates (2) fixed side by side along the width direction of the PCB board (1), one RX optical fiber array (3) is fixed on the upper surface of each ceramic substrate (2), one array PD chip (4) coupled with the RX optical fiber array (3) is fixed on the upper surface of each ceramic substrate (2), two ceramic blocks (5) with the same height as the ceramic substrates (2) are fixed side by side along the width direction of the PCB board (1), one TIA chip (6) is fixed on the upper surface of each ceramic block (5), the TIA chip (6) is gold wire bonded with the array PD chip (4), and the TIA chip (6) is gold wire bonded with the PCB board (1). The thickness of the ceramic substrate (2) is 0.2-0.4 mm.
2. The 800G DR8 silicon optical module of claim 1, wherein, The thickness of the ceramic substrate (2) is 0.25 mm.
3. The 800G DR8 silicon optical module of claim 2, wherein, The ceramic block (5) is gold plated, the ceramic block (5) is bonded with the GND pad of the PCB board (1) by using conductive silver glue, and the TIA chip (6) is electrically connected with the GND pad of the PCB board (1) through the gold layer plated on the ceramic block (5) and the conductive silver glue.
4. The 800G DR8 silicon optical module of claim 1, wherein, The ceramic substrate (2) is made of aluminum nitride.
5. The 800G DR8 silicon optical module of any one of claims 1-4, wherein, The RX optical fiber array (3) and the array PD chip (4) are respectively bonded and fixed on the ceramic substrate (2).
6. The 800G DR8 silicon optical module of any one of claims 1-4, wherein,