CN110879444A

CN110879444A - Optical module and communication device

Info

Publication number: CN110879444A
Application number: CN201911219284.2A
Authority: CN
Inventors: 黄愚; 周斌; 陈骁; 李海坚; 黄旭
Original assignee: Guangwei Technology (guangzhou) Co Ltd
Current assignee: Guangwei Technology (guangzhou) Co Ltd; Liturex Guangzhou Co Ltd
Priority date: 2019-11-30
Filing date: 2019-11-30
Publication date: 2020-03-13

Abstract

The invention discloses an optical module and communication equipment, wherein the optical module comprises a substrate, an electric chip, a high-speed signal wire and a capacitor, the electric chip, the high-speed signal wire and the capacitor are arranged on the substrate, the capacitor is connected between the electric chip and the high-speed signal wire, the capacitor comprises a first polar plate and a second polar plate, the first polar plate is connected with a corresponding bonding pad of the electric chip through a signal bonding wire, and the second polar plate is connected with the high-speed signal wire. Because the electric chip is directly connected to the capacitor through the bonding wire, the capacitor is connected to the high-speed signal wire, and the electric chip is not connected to the high-speed signal wire through the bonding wire and the capacitor is arranged in the middle section of the path of the high-speed signal wire, the impedance discontinuity point on the high-speed signal transmission path is reduced, and the integrity of the high-speed signal is improved.

Description

Optical module and communication device

Technical Field

The invention relates to the technical field of optical communication, in particular to an optical module and communication equipment.

Background

With the rapid development of modern optical fiber communication, the optical transmission rate is rapidly increased, and especially under the requirement of a 5G system, the signal rate of an optical device is higher and higher, and meanwhile, the power consumption and the price of the optical device are required to be smaller. Therefore, the COB (chip optical module) structure has started to be used for a large scale, and the COB optical module structure is characterized by being simple, and all the optical and electrical devices are placed on the substrate (the substrate may be a circuit board or a metal plate). Therefore, a box body and a process for packaging the OSA are omitted, and the structure is greatly simplified. However, the too simple structure brings new problems, no matter what structure, the high-speed electrical signal is transmitted between the optical module and the electrical chip, and the gold wire bonding (commonly called gold wire bonding) is often used for building the high-speed electrical signal, which is the application of one gold wire bonding as shown in fig. 2. With the improvement of modern communication speed, high-speed lines for signal transmission have higher and higher signal integrity requirements, that is, requirements for signal transmission without errors are met for high-speed electric signals, a signal transmission path must have impedance continuity, gold wires are used as connection parts and are often places for destroying impedance continuity, and the length of the gold wires has a great influence on impedance discontinuity, so that the gold wires on the high-speed lines are generally required to be as short as possible. Referring to fig. 1 and fig. 2, which are a conventional BOX package structure and a COB structure, respectively, it can be seen that in the BOX package structure, due to the step structure 101 inside the BOX, the heights of the electrical chip 102 and the gold wire bonding pad 103 are substantially flush, so that the length of the gold wire 104 can be extremely short; in the COB structure (taking the substrate as the circuit board 200 as an example), the wire bonding pad 203 is on the surface of the circuit board 200, and the chip 202 is also attached to the circuit board 200, so that the wire bonding pad 205 on the chip 202 and the wire bonding pad 203 on the circuit board 200 have a height difference, and due to the process characteristics of the gold wire 204, the height difference will tend to increase the length of the gold wire 204, which in turn will affect the impedance continuity of the high-speed circuit, resulting in the problem of signal integrity. The optical module exhibits such performances as poor eye pattern and reduced sensitivity in terms of overall performance. On the high-speed signal line path of the optical module with the typical COB structure shown in fig. 2, both sides of the bond wire 204 and both sides of the capacitor 206 are positions where impedance discontinuities occur, which may compromise signal integrity.

Disclosure of Invention

The invention aims to provide an optical module which can reduce impedance discontinuous points on a high-speed signal transmission path and improve the integrity of a high-speed signal.

Another object of the present invention is to provide a communication device, which can reduce impedance discontinuity on a high-speed signal transmission path and improve the integrity of a high-speed signal.

In order to achieve the above object, the present invention provides an optical module, which includes a substrate, an electrical chip, a high-speed signal line, and a capacitor, where the electrical chip, the high-speed signal line, and the capacitor are disposed on the substrate, the capacitor is connected between the electrical chip and the high-speed signal line, the capacitor includes a first electrode plate and a second electrode plate, the first electrode plate is connected to a corresponding pad of the electrical chip through a signal bonding wire, and the second electrode plate is connected to the high-speed signal line.

Preferably, the substrate is provided with two capacitor pads corresponding to the capacitors, one of the two capacitor pads is connected to the high-speed signal line, and the first and second plates of the capacitors are respectively soldered to the two capacitor pads.

Preferably, a capacitor pad corresponding to the capacitor and connected to the high-speed signal line is disposed on the substrate, the second plate of the capacitor is soldered to the capacitor pad, and the first plate of the capacitor faces upward.

Preferably, the first plate of the capacitor is disposed proximate to the electrical chip.

Preferably, the signal bonding wire is bonded on the upper surface of the first plate of the capacitor.

Preferably, the optical module is a COB optical module.

Preferably, an end of the high-speed signal line opposite to the capacitor is connected to an optical chip or a connector.

Preferably, a metal ground is further disposed on the substrate, and the electric chip is bonded to the metal ground through a ground bonding wire.

To achieve another object, the present invention provides a communication device including the optical module as described above.

Compared with the prior art, the capacitor of the optical module is connected between the electric chip and the high-speed signal line, the first polar plate of the capacitor is connected with the bonding pad of the electric chip through the signal bonding wire, and the second polar plate of the capacitor is connected with the high-speed signal line. That is, in the present invention, the electric chip is directly connected to the capacitor through the bonding wire, and the capacitor is connected to the high-speed signal line, instead of being connected to the high-speed signal line through the bonding wire and setting the capacitor at the middle section of the path of the high-speed signal line, thereby reducing the impedance discontinuity on the high-speed signal transmission path and improving the integrity of the high-speed signal.

Drawings

Fig. 1 is a schematic perspective view of an optical module of a conventional BOX package structure.

Fig. 2 is a schematic perspective view of an optical module of a conventional COB package structure.

Fig. 3 is a schematic perspective view of an optical module according to an embodiment of the present invention.

Fig. 4 is an enlarged schematic view of a portion a in fig. 3.

Fig. 5 is a schematic perspective view of an optical module according to another embodiment of the present invention.

Fig. 6 is an enlarged schematic view of a portion B in fig. 5.

Detailed Description

In order to explain technical contents and structural features of the present invention in detail, the following description is made with reference to the embodiments and the accompanying drawings.

Referring to fig. 3 to 6, the present invention discloses an optical module, which includes a substrate 1, an electrical chip 2, a high-speed signal line 3, and a capacitor 4/5, wherein the electrical chip 2, the high-speed signal line 3, and the capacitor 4/5 are disposed on the substrate 1, the capacitor 4/5 is connected between the electrical chip 2 and the high-speed signal line 3, the capacitor 4/5 includes a first plate 41/51 and a second plate 42/52, the first plate 41/51 is connected to a corresponding pad 21 of the electrical chip 2 through a signal bonding wire 6, and the second plate 42/52 is connected to the high-speed signal line 3. Generally, the signal bonding wire 6 is bonded to the upper surface of the first plate 41/51, but not limited thereto. In the example shown in the drawing, the optical module includes two high-speed signal lines 3, and capacitances 4/5 are connected between the two high-speed signal lines 3 and corresponding pads 21 of the electric chip 2, respectively. The "optical module" herein may be an optical module having a COB or BOX package structure, and is not limited herein.

The electric chip 2 of the optical module is directly connected to the capacitor 4/5 through the bonding wire 6, the capacitor 4/5 is connected to the high-speed signal line 3, instead of being connected to the high-speed signal line 3 through the bonding wire 6 and the capacitor 4/5 is arranged in the middle of the path of the high-speed signal line 3 (which is equivalent to removing a section of the high-speed signal line 3 between the capacitor 4/5 and the signal bonding wire 6), so that impedance discontinuity on the high-speed signal transmission path is reduced, and the integrity of the high-speed signal is improved.

Referring to fig. 3 and 4, in some embodiments, two capacitor pads 7 corresponding to the capacitor 4 are disposed on the substrate 1, one of the two capacitor pads 7 is connected to the high-speed signal line 3, and the first plate 41 and the second plate 42 of the capacitor 4 are respectively soldered on the two capacitor pads 7. In the example shown in fig. 5, since the two high-speed signal lines 3 and the electric chip 2 are connected with the capacitors 4, respectively, two capacitor pads 7 are provided on the substrate 1 for the two capacitors 4, respectively.

Referring to fig. 5 and 6, in other embodiments, a capacitor pad 8 corresponding to the capacitor 5 and connected to the high-speed signal line 3 is disposed on the substrate 1, the second plate 52 of the capacitor 5 is soldered to the capacitor pad 8, and the first plate 51 of the capacitor 5 faces upward. In the example shown in fig. 6, since the two high-speed signal lines 3 and the electric chip 2 are connected with the capacitors 5, respectively, one capacitor pad 8 is provided on the substrate 1 for each of the two capacitors 5.

Referring to fig. 3-6, in a preferred embodiment, the first plate 41/51 of the capacitor 4/5 is disposed proximate to the electrical chip 2. Generally speaking, the capacitor 4/5 is spaced from the electrical chip 2 by a small distance to avoid interference with the electrical chip 2, although it is not excluded that the capacitor 4/5 and the electrical chip 2 are in contact with each other, as long as the interference between the capacitor 4/5 and the electrical chip 2 can be controlled, and can be as close as possible. Since the first plate 41/51 of the capacitor 4/5 is disposed next to the electrical chip 2, and the capacitor 4/5 itself has a certain height, when the corresponding pad 21 of the electrical chip 2 and the first plate 41/51 of the capacitor 4/5 are connected by the signal bonding wire 6, the bonding position of the signal bonding wire 6 on the first plate 41/51 may have a certain height relative to the substrate 1, which is favorable for reducing the height difference between the bonding position of the corresponding pad 21 of the electrical chip 2 and the bonding position on the first plate 41/51, so that the length of the signal bonding wire 6 may be shortened. Generally, the signal bonding wire 6 is bonded on the upper surface of the first plate 41/51 of the capacitor 4/5 to facilitate the wire bonding operation of the signal bonding wire 6 and reduce the height difference of the wire bonding, but not limited thereto.

Specifically, the optical module is a COB optical module, but not limited thereto.

Referring to fig. 3 and 5, in some embodiments, the end of the high-speed signal line 3 opposite to the capacitor 4/5 is connected to an optical chip (not shown) or a connector (not shown). In the specific example shown in the drawing, the end of the high-speed signal line 3 opposite to the capacitance 4/5 is connected with a gold finger 9 to be connected with a connector through the gold finger 9.

Referring to fig. 3 to 6, in some embodiments, a metal ground 10 is further disposed on the substrate 1, and the electric chip 2 is bonded to the metal ground 10 through a ground bonding wire 11.

Referring to fig. 3 to fig. 6, the present invention further discloses a communication device including the optical module.

In summary, the capacitor 4/5 of the optical module of the present invention is connected between the electrical chip 2 and the high-speed signal line 3, the first plate 41/51 of the capacitor 4/5 is connected to the pad 21 of the electrical chip 2 through the signal bonding wire 6, and the second plate 42/52 of the capacitor 4/5 is connected to the high-speed signal line 3. That is, in the present invention, the electrical chip 2 is directly connected to the capacitor 4/5 through the bonding wire 6, and the capacitor 4/5 is connected to the high-speed signal line 3 instead of being connected to the high-speed signal line 3 through the bonding wire 6 and the capacitor 4/5 is disposed in the middle of the path of the high-speed signal line 3, so that the impedance discontinuity on the high-speed signal transmission path is reduced, and the integrity of the high-speed signal is improved. Moreover, the invention has simple implementation mode and is easy to implement.

The above disclosure is only a preferred embodiment of the present invention, and should not be taken as limiting the scope of the invention, so that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.

Claims

1. An optical module is characterized by comprising a substrate, an electric chip, a high-speed signal line and a capacitor, wherein the electric chip, the high-speed signal line and the capacitor are arranged on the substrate, the capacitor is connected between the electric chip and the high-speed signal line, the capacitor comprises a first polar plate and a second polar plate, the first polar plate is connected with a corresponding bonding pad of the electric chip through a signal bonding wire, and the second polar plate is connected with the high-speed signal line.

2. The optical module according to claim 1, wherein two capacitor pads corresponding to the capacitors are provided on the substrate, one of the two capacitor pads is connected to the high-speed signal line, and a first plate and a second plate of the capacitors are respectively soldered to the two capacitor pads.

3. The optical module according to claim 1, wherein a capacitor pad corresponding to the capacitor and connected to the high-speed signal line is provided on the substrate, the second plate of the capacitor is soldered to the capacitor pad, and the first plate of the capacitor is faced upward.

4. A light module as claimed in claim 2 or 3, characterized in that the first plate of the capacitor is arranged next to the electric chip.

5. The optical module of claim 4 wherein the signal bond wire is bonded to an upper surface of the first plate of the capacitor.

6. The optical module of claim 4, wherein the optical module is a COB optical module.

7. An optical module as claimed in claim 1, wherein an end of the high speed signal line opposite to the capacitor is connected to an optical chip or a connector.

8. The optical module of claim 1, wherein said substrate further has a metal ground thereon, and said electrical chip is bonded to said metal ground by a ground wire bond.

9. A communication device, characterized in that it comprises a light module according to any one of claims 1 to 8.