EML optical device carrier plate interconnection structure

Abstract

The utility model provides an EML optical device carrier plate interconnection structure, which comprises a substrate, a first bonding pad group and a plurality of sections of transmission lines, the first bonding pad group and the plurality of sections of transmission lines are embedded on the substrate, the plurality of sections of transmission lines are sequentially connected end to end, and one ends of the connected transmission lines are connected with the first bonding pad group. The other end of the first bonding pad group is in bonding connection with a bonding pad of the laser chip through a gold thread and is matched with the bonding pad of the laser chip, and the first bonding pad group is also in bonding connection with a second bonding pad group on the EML optical device base through a gold thread and is matched with the second bonding pad group; wherein the multiple sections of transmission lines are connected to form a multi-stage interconnection structure, the multi-stage interconnection structure is arranged between two impedance abrupt change points introduced by gold wire bonding, and the sectional interconnection impedance can be changed by changing the line width of each section of transmission line. According to the EML optical device carrier plate interconnection structure provided by the utility model, the change of a link impedance curve is smoother, the frequency domain reflection of the whole interconnection channel is reduced, and the product performance is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of optical modules, and particularly relates to an interconnection structure for an EML optical device carrier board. Background Art

[0002] In an EML optical device, there is generally a carrier board. One end of the carrier board is connected to an LD (Laser Diode) chip through a gold wire, and the other end is connected to the base of the EML optical device through a gold wire. Impedance mismatches will occur at both of these connection points. Impedance mismatch refers to the situation of unmatched impedance in an electronic circuit or communication system, that is, the signal transmission problem caused by the inconsistent impedance between the signal source and the load. Due to the unmatched impedance, problems such as reflection, attenuation, and power loss occur during signal transmission. Impedance mismatch can affect signal quality, interfere with transmission, and limit system performance. Therefore, an interconnection structure is needed to reduce the problem of bandwidth reduction caused by impedance mismatch at the gold wire. Summary of the Utility Model

[0003] The purpose of the utility model is to provide an interconnection structure for an EML optical device carrier board to solve the problem that impedance mismatches occur at the connection points of the current optical device carrier board, and the bandwidth of the interconnection structure is reduced accordingly, affecting the channel signal quality. The specific technical solutions are as follows:

[0004] An interconnection structure for an EML optical device carrier board includes a substrate and a first pad group and multiple segments of transmission lines embedded in the substrate. The multiple segments of transmission lines are connected end to end in sequence to form a multi-stage interconnection structure, and the multi-stage interconnection structure changes the segmented interconnection impedance by changing the line width of the transmission lines;

[0005] One end of the multi-stage interconnection structure is connected to the first pad group, the other end is connected to the pad of the laser chip, and the first pad group is also connected to a second pad group on the substrate of the EML optical device base.

[0006] Further, the multiple segments of transmission lines include a first transmission line, a second transmission line, a third transmission line, a fourth transmission line, and a fifth transmission line. The first transmission line is connected to the first pad group, and the fifth transmission line is connected to the pad of the laser chip.

[0007] Further, the first pad group and the second pad group on the substrate of the EML optical device base are connected and formed into a match through first gold wire bonding, and the fifth transmission line and the pad of the laser chip are connected and formed into a match through second gold wire bonding.

[0008] Further, the line width of the second transmission line satisfies an impedance of 50 ohms, and the line width of the first transmission line is less than that of the second transmission line and is between the first gold wire and the second transmission line.

[0009] Further, the line width of the third transmission line is smaller than that of the second transmission line, the line width of the third transmission line is also smaller than that of the fourth transmission line, and the line width of the fourth transmission line is smaller than that of the fifth transmission line.

[0010] Further, the impedance of the second gold wire is higher than 50 ohms, and the line width of the fifth transmission line is greater than that of the second transmission line.

[0011] Further, the distance between the first pad group and the second pad group is matched to meet the bonding of at least two gold wires, and via holes are provided in the two GND pads of the first pad group.

[0012] Further, a GND via hole is provided at the bottom of the laser chip.

[0013] An EML optical device carrier board interconnection structure provided by the present utility model has the following beneficial effects:

[0014] An EML optical device carrier board interconnection structure provided by the present utility model adopts a multi-stage impedance matching scheme, designs multi-stage different interconnection impedance values near the impedance mismatch point, optimizes the impedance curve fluctuation, can greatly reduce the reflection of the entire interconnection channel in the frequency domain, and optimizes the product performance. Description of the Drawings

[0015] Figure 1 is a schematic diagram of an EML optical device carrier board interconnection structure provided by the present utility model.

[0016] Reference numerals: 1 - substrate; 2 - first pad group; 3 - first transmission line; 4 - second transmission line; 5 - third transmission line; 6 - fourth transmission line; 7 - fifth transmission line; 8 - laser chip; 9 - optical device base; 10 - second pad group. Detailed Embodiments

[0017] The technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the drawings provided by the present utility model. According to the following description, the advantages and features of the present utility model will be clearer. It should be noted that the drawings are all in a very simplified form and use non-precise scales, only for the purpose of facilitating and clearly assisting in explaining the objectives of the embodiments of the present utility model.

[0018] In the description of the present utility model, unless otherwise clearly defined and limited, the terms "connection" and "coupling" shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral one; it may be a mechanical connection or an electrical connection; it may be a direct connection or an indirect connection through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0019] In the description of the present utility model, the orientation or positional relationships such as "upper", "lower", "left", "right", "front", "rear", "center", "horizontal", "vertical", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings. It is only for the convenience of description and simplifying the operation, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present utility model.

[0020] Embodiment:

[0021] This embodiment provides an EML optical device carrier board interconnection structure. Referring to Figure 1 as shown, the interconnection structure includes a substrate 1 and a first pad group 2, a first transmission line 3, a second transmission line 4, a third transmission line 5, a fourth transmission line 6, and a fifth transmission line 7 on the substrate 1. Among them, the first transmission line 3, the second transmission line 4, the third transmission line 5, the fourth transmission line 6, and the fifth transmission line 7 are sequentially connected end to end to form a multi-stage interconnection structure. The first transmission line 3 in the multi-stage interconnection structure is connected to the first pad group 2, the fifth transmission line 7 is connected to the pad 8 of the laser chip, and at the same time, the first pad group 2 is also connected to the second pad group 10 on the substrate 9 of the EML optical device base.

[0022] For the above EML optical device carrier board interconnection structure provided by the present utility model, the connection between the first pad group 2 and the second pad group 10 on the substrate 9 of the EML optical device base forms impedance matching, and the connection between the fifth transmission line 7 and the pad 8 of the laser chip forms impedance matching. The first transmission line 3, the second transmission line 4, the third transmission line 5, and the fourth transmission line 6 between them form a multi-stage interconnection structure. The multi-stage interconnection structure can greatly reduce the reflection of the entire interconnection channel in the frequency domain and improve the product performance.

[0023] The following is a specific description of the EML optical device carrier board interconnection structure.

[0024] As a specific implementation of the first pad group 2 and the second pad group 10, the first pad group 2 is embedded on one side of the substrate 1 close to the EML optical device base substrate 9, and is matched with the second pad group 10 on the EML optical device base substrate 9 through the first gold wire bonding connection. The spacing between the first pad group 2 and the second pad group 10 is matched, which can meet the bonding of at least two gold wires. In addition, two via holes for return current are provided on the two GND pads of the first pad group 2 to provide a return path for high-speed signals.

[0025] As a specific implementation of the multi-level interconnection structure, multiple transmission lines form a multi-level interconnection structure. The multiple transmission lines include a first transmission line 3, a second transmission line 4, a third transmission line 5, a fourth transmission line 6, and a fifth transmission line 7. The multiple transmission lines are all embedded in the substrate 1 and are connected end to end in sequence. The first transmission line 3 is connected to the first pad group 2, and the fifth transmission line 7 and the pad 8 of the laser chip are matched through the second gold wire bonding connection. The line width of the first transmission line 3 is smaller than that of the second transmission line 4, and the line width of the second transmission line 4 satisfies an impedance of 50 ohms. The impedance of the first transmission line 3 is between the first gold wire and the second transmission line 4, which can make the impedance drop between the gold wire and the 50-ohm impedance line slower. Similarly, the line width of the third transmission line 5 is smaller than that of the fourth transmission line 6, and the line width of the fourth transmission line 6 is smaller than that of the fifth transmission line 7, which is also to avoid too large a drop in impedance during the impedance change process. At the same time, the impedance of the second gold wire between the fifth transmission line 7 and the laser chip 8 is higher than 50 ohms, so the line width of the fifth transmission line 7 is larger than that of the second transmission line 4, and the fifth transmission line 7 can introduce a part of capacitance to reduce the impedance at the gold wire. In addition, a GND via hole is provided at the bottom of the laser chip for high-speed signals to return to the negative pole of the chip. The above multi-level interconnection structure mainly changes the segmented interconnection impedance by changing the line width of the transmission line, thereby being able to greatly reduce the reflection of the entire interconnection channel in the frequency domain and improve the product performance.

[0026] Those skilled in the art of the present technology should understand that the present utility model can be implemented in many other specific forms without departing from the spirit and scope of the present utility model. Based on the embodiments in the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

Claims

1. An EML optical device carrier board interconnection structure, characterized in that: It includes a substrate, a first pad group embedded on the substrate, and multiple segments of transmission lines. The multiple segments of transmission lines are connected end to end in sequence to form a multi-stage interconnection structure, and the multi-stage interconnection structure changes the segmented interconnection impedance by changing the line width of the transmission lines. One end of the multi-stage interconnection structure is connected to the first pad group, and the other end is connected to the pads of the laser chip. The first pad group is also connected to the second pad group on the substrate of the EML optical device base.

2. The EML optical device carrier board interconnection structure according to claim 1, characterized in that: The multiple segments of transmission lines include a first transmission line, a second transmission line, a third transmission line, a fourth transmission line, and a fifth transmission line. The first transmission line is connected to the first pad group, and the fifth transmission line is connected to the pads of the laser chip.

3. The EML optical device carrier board interconnection structure according to claim 2, wherein: The first pad group and the second pad group on the substrate of the EML optical device base are connected and matched by first gold wire bonding, and the fifth transmission line and the pads of the laser chip are connected and matched by second gold wire bonding.

4. The EML optical device carrier board interconnection structure according to claim 3, wherein: The line width of the second transmission line satisfies an impedance of 50 ohms. The line width of the first transmission line is less than that of the second transmission line and is between the first gold wire and the second transmission line.

5. The EML optical device carrier board interconnection structure according to claim 4, characterized in that: The line width of the third transmission line is less than that of the second transmission line. The line width of the third transmission line is also less than that of the fourth transmission line. The line width of the fourth transmission line is less than that of the fifth transmission line.

6. The EML optical device carrier board interconnection structure according to claim 5, characterized in that: The impedance of the second gold wire is higher than 50 ohms. The line width of the fifth transmission line is greater than that of the second transmission line.

7. The EML optical device carrier board interconnection structure according to any one of claims 1-6, characterized in that: The spacing between the first pad group and the second pad group is matched to meet at least two gold wire bondings. Two GND pads of the first pad group are provided with return current vias.

8. The EML optical device carrier board interconnection structure according to claim 7, characterized in that: One GND return current via is provided at the bottom of the laser chip.

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