Optical module packaging structure and optical module

Abstract

The invention discloses an optical module packaging structure and an optical module. The optical module packaging structure comprises a printed circuit board; a plurality of mounting grooves are formed in the end part of the overlapped part of the bottom plate and the printed circuit board at intervals; the number of the EML assemblies is equal to that of the mounting grooves, the EML assemblies are in one-to-one correspondence with the mounting grooves, and the EML assemblies comprise chip packaging substrates which are located in the mounting grooves and connected with the bottom plate; the EML laser chip is located in the mounting groove and connected with the chip packaging substrate, the printed circuit board is electrically connected with the EML laser chip through a first differential signal line and a second differential signal line on the printed circuit board, and the first differential signal line and the second differential signal line form differential routing; the coupling lens is arranged on the bottom plate and is close to the EML laser chip; and the filter capacitor is arranged on the printed circuit board and is electrically connected with the EML laser chip. According to the optical module packaging structure provided by the invention, the EML laser chip is driven by adopting a differential driving mode, so that the optical module packaging structure has higher anti-interference capability, and meanwhile, the signal transmission quality is improved.

Description

Technical Field

[0001] The present invention relates to the field of optoelectronic device packaging. More specifically, the present invention relates to an optical module packaging structure and an optical module. Background Art

[0002] In recent years, with the development of AI technology, big data and large models have put forward higher requirements for computer computing power, which means that optical communication technology needs to be able to carry higher transmission capacities. For data center scenarios, the transmission rate has iterated from 10 Gbps per single wavelength to 200 Gbps today. Electro-absorption modulated lasers (EMLs) have become ideal light sources in data center scenarios due to their advantages such as small size, low packaging cost, low drive voltage, low chirp, and good reliability. Currently, the packaging of this light source chip usually adopts a single-ended driving method. Compared with differential driving, the driving ability is insufficient and the anti-interference ability is weak, and the disadvantages are gradually revealed in high-speed scenarios. Summary of the Invention

[0003] The purpose of the present invention is to provide an optical module packaging structure and an optical module to realize driving an EML chip in a differential routing manner.

[0004] To achieve these and other advantages in accordance with the present invention, there is provided an optical module packaging structure, comprising:

[0005] A printed circuit board;

[0006] A bottom plate, which partially overlaps with the printed circuit board, and a plurality of mounting grooves are provided at intervals at the end of the overlapping part of the printed circuit board and the bottom plate;

[0007] An EML component, which is equal in number to and corresponds one-to-one with the mounting grooves, and the EML component comprises:

[0008] A chip packaging substrate, which is located in the mounting groove and connected to the bottom plate;

[0009] An EML laser chip, which is located in the mounting groove and connected to the chip packaging substrate, and the printed circuit board is electrically connected to the EML laser chip through a first differential signal line and a second differential signal line thereon, and the first differential signal line and the second differential signal line form a differential routing;

[0010] A coupling lens, which is arranged on the bottom plate and close to the EML laser chip, and is optically aligned and connected to the EML laser chip through active optical coupling;

[0011] A filter capacitor, which is arranged on the printed circuit board and electrically connected to the EML laser chip.

[0012] Further, in the optical module packaging structure, the end of the overlapping part of the printed circuit board and the bottom plate is a serrated structure to form a plurality of the mounting grooves.

[0013] Further, in the optical module packaging structure, the EML component further includes:

[0014] A connection substrate, and the coupling lens is connected to the bottom plate through the connection substrate.

[0015] Further, in the optical module packaging structure, the bottom plate is a substrate or a thermoelectric cooler.

[0016] Further, in the optical module packaging structure, a plurality of pad assemblies equal in number to and corresponding one-to-one with the EML laser chips are provided on the printed circuit board, and the EML laser chips are electrically connected to the printed circuit board and the filter capacitor through the pad assemblies.

[0017] Further, in the optical module packaging structure, a first metallization layer and chip gold-tin solder are provided at one end of the chip packaging substrate close to the EML laser chip, and a second metallization layer is provided at one end thereof close to the bottom plate. The gnd of the first metallization layer is connected to the gnd of the second metallization layer. The EML laser chip is connected to the chip packaging substrate through the chip gold-tin solder and is electrically connected to the pad assembly through the first metallization layer.

[0018] Further, in the optical module packaging structure, at least one through hole is provided on the chip packaging substrate, and the through hole is filled with a conductor, and the conductor is respectively connected to the gnd of the first metallization layer and the gnd of the second metallization layer.

[0019] Further, in the optical module packaging structure, the pad assembly includes a first differential signal line pad, a second differential signal line pad, a filter capacitor pad, a first ground pad, and a power supply pad. The first differential signal line pad is connected to the first differential signal line, the second differential signal line pad is connected to the second differential signal line, and the filter capacitor pad is connected to the filter capacitor;

[0020] An EA signal pad and a laser power supply pad are provided on the EML laser chip, and the laser power supply pad is connected to the power supply pad;

[0021] The first metallization layer includes:

[0022] A first EA matching RC filter circuit resistor pad, which is connected to both the second differential signal line pad and the EA signal pad;

[0023] The second EA matching RC filter circuit resistor pad is respectively connected to the first EA matching RC filter circuit resistor pad and the filter capacitor pad;

[0024] The termination resistor pad is connected to the first differential signal line pad;

[0025] The second ground pad is respectively connected to the termination resistor pad and the first ground pad.

[0026] Furthermore, in the optical module packaging structure, the first EA matching RC filter circuit resistor pad and the second EA matching RC filter circuit resistor pad are connected by a first thin film resistor, and the termination resistor pad and the second ground pad are connected by a second thin film resistor.

[0027] The present invention also provides an optical module, including the above optical module packaging structure.

[0028] The beneficial effects of the present invention are:

[0029] In the optical module packaging structure of the present invention, a differential driving method is adopted to drive the EML laser chip, which has stronger anti-interference ability, and at the same time improves the signal transmission quality of the EML laser chip, and can be applied to higher speed scenarios.

[0030] Other advantages, objectives and features of the present invention will be partially reflected by the following description, and partially will also be understood by those skilled in the art through the research and practice of the present invention. Description of the Drawings

[0031] Figure 1 It is a schematic structural diagram of the optical module packaging structure described in the present invention;

[0032] Figure 2 It is a top view of the optical module packaging structure described in the present invention;

[0033] Figure 3 It is a partial structural schematic diagram of the optical module packaging structure described in the present invention;

[0034] Figure 4 It is a schematic structural diagram of the chip packaging substrate described in the present invention;

[0035] Figure 5 It is a side view of the chip packaging substrate described in the present invention;

[0036] Figure 6 It is a top view of the chip packaging substrate described in the present invention;

[0037] Figure 7 It is a connection schematic diagram of the chip packaging substrate and the EML laser chip described in the present invention.

[0038] Among them, the reference signs are as follows:

[0039] Bottom plate 1; Printed circuit board 2; First differential signal line pad 201; Second differential signal line pad 202; Filter capacitor pad 203; Power supply pad 204; First ground pad 205; Filter capacitor 206; First differential signal line 207; Second differential signal line 208; Chip packaging substrate 3; First metallization layer 301; First EA matching RC filter circuit resistor pad 3011; Second EA matching RC filter circuit resistor pad 3012; Termination resistor pad 3013; Second ground pad 3014; Second metallization layer 302; Through hole 303; Thin film resistor 304; First thin film resistor 3041; Second thin film resistor 3042; Chip AuSn solder 305; EML laser chip 4; EA signal pad 401; Laser power supply pad 402; Connection substrate 5; Coupling lens 6. Detailed implementation manners

[0040] The following further elaborates on the present invention in conjunction with embodiments, so that those skilled in the art can implement it with reference to the description in the specification.

[0041] It should be noted that in the description of the present invention, the orientation or positional relationships indicated by the terms "lateral", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings. These are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0042] As Figure 1 - Figure 2 shown, an embodiment of the present invention provides an optical module packaging structure, including:

[0043] Printed circuit board 2;

[0044] Bottom plate 1, which partially overlaps with the printed circuit board 2, and a plurality of mounting grooves are provided at intervals at the end of the overlapping part of the printed circuit board 2 and the bottom plate 1; According to the actual situation, the bottom plate 1 can be a substrate or a thermoelectric cooler.

[0045] EML components, the number of which is equal to and corresponds one-to-one with the number of the mounting grooves, and the EML components include:

[0046] Chip packaging substrate 3, which is located in the mounting groove and connected to the bottom plate 1; The EML laser chip 4 is fixed through the chip packaging substrate 3, and at the same time, the chip packaging substrate 3 provides an electrical characteristic matching function for the EML laser chip 4.

[0047] The EML laser chip 4 is located in the mounting groove and connected to the chip packaging substrate 3, and the EML laser chip 4 is electrically connected to the printed circuit board 2; the printed circuit board 2 is electrically connected to the EML laser chip 4 through the first differential signal line 207 and the second differential signal line 208 thereon, and the first differential signal line 207 and the second differential signal line 208 form a differential trace;

[0048] The coupling lens 6 is arranged on the base plate 1 and close to the EML laser chip 4, and is optically aligned and connected to the EML laser chip 4 through active optical coupling;

[0049] The filter capacitor 206 is arranged on the printed circuit board 2 and electrically connected to the EML laser chip 4.

[0050] Among them, a plurality of pad assemblies equal in number to and corresponding one-to-one with the EML laser chips 4 are arranged on the printed circuit board 2, and the EML laser chips 4 are respectively electrically connected to the printed circuit board 2 through the corresponding pad assemblies. As Figure 4 shown, one end of the chip packaging substrate 3 close to the EML laser chip 4 is provided with a first metallization layer 301 and a chip gold-tin solder 305, and one end of it close to the base plate 1 is provided with a second metallization layer 302. The gnd of the first metallization layer 301 is connected to the gnd of the second metallization layer 302. The EML laser chip 4 is connected to the chip packaging substrate 3 through the chip gold-tin solder 305 and electrically connected to the pad assembly through the first metallization layer 301.

[0051] As Figure 3 shown, the pad assembly includes a first differential signal line pad 201, a second differential signal line pad 202, a filter capacitor pad 203, a first ground pad 205 and a power supply pad 204;

[0052] As Figure 7 shown, the EML laser chip 4 is provided with an EA signal pad 401 and a laser power supply pad 402, and the laser power supply pad 402 is connected to the power supply pad 204; a first thin film resistor 3041 is arranged between the first EA matching RC filter circuit resistor pad 3011 and the second EA matching RC filter circuit resistor pad 3012, and a second thin film resistor 3042 is arranged between the termination resistor pad 3013 and the second ground pad 3014; Figure 7 The thick black lines are gold wire bonding diagrams, representing the connection relationships between the pads;

[0053] As Figure 4 - 6 shown, the first metallization layer 301 includes:

[0054] The first EA matching RC filter circuit resistor pad 3011 is connected to both the second differential signal line pad 202 and the EA signal pad 401;

[0055] The second EA matching RC filter circuit resistor pad 3012 is connected to the filter capacitor pad 203;

[0056] The termination resistor pad 3013 is connected to the first differential signal line pad 201;

[0057] The second ground pad 3014 is connected to the first ground pad 205.

[0058] In this embodiment, one end of the first differential signal line 207 is connected to the first differential signal line pad 201, and the other end crosses the EML laser chip 44 and is connected to the termination resistor pad 3013. The termination resistor pad 3013 is connected to the second ground pad 3014 through the second thin film resistor 3042, and the second ground pad 3014 is connected to the first ground pad 205 to realize signal ground return. One end of the second differential signal line 208 is connected to the second differential signal line pad 202, and the other end is connected to the EA signal pad 401. The EA signal pad 401 is connected to the first EA matching RC filter circuit resistor pad 3011. The first EA matching RC filter circuit resistor pad 3011 is connected to the second EA matching RC filter circuit resistor pad 3012 through the first thin film resistor 3041. The second EA matching RC filter circuit resistor pad 3012 is connected to the filter capacitor pad 203, and the filter capacitor pad 203 is connected to the filter capacitor 206. The filter capacitor 206, the filter capacitor pad 203, the second EA matching RC filter circuit resistor pad 3012, the first thin film resistor 3041, and the first EA matching RC filter circuit resistor pad 3011 form an RC filter circuit. The connection between the RC filter circuit and the EA signal pad 401 realizes the signal transmission between the printed circuit board 2 and the EML laser chip 4. The laser power supply pad 402 is connected to the power supply pad 204 on the printed circuit board 2 to power the EML laser chip 44 to realize the light output of the laser. The characteristic of the optical module packaging structure in the embodiment is that the differential traces are directly arranged next to the chip, and differential termination is performed on the chip substrate. Compared with the existing differential output where differential termination is performed on the printed circuit board 2 and then separately output to the packaging substrate, and there are long single-ended traces on the substrate, the loss caused by the long single-ended transmission path can be significantly reduced, and the signal quality can be improved.

[0059] Preferably, as another embodiment of the present invention, the end of the overlapping part of the printed circuit board 2 and the bottom plate 1 is a serrated structure to form a plurality of the mounting grooves.

[0060] In this embodiment, the end of the overlapping part of the printed circuit board 2 and the base plate 1 is set as a serrated structure, forming a plurality of uniformly distributed mounting grooves, which is convenient for arranging corresponding pads on the printed circuit board 2.

[0061] Preferably, as another embodiment of the present invention, the EML component further includes:

[0062] A connection substrate 5, and the coupling lens 6 is connected to the base plate 1 through the connection substrate 5.

[0063] In this embodiment, the connection substrate 5 is used to adjust the thickness of the lens glue and the mounting height of the coupling lens 6 to ensure the reliability of the coupling lens 6.

[0064] Preferably, as another embodiment of the present invention, at least one through hole 303 is provided on the chip packaging substrate 3, and the through hole 303 is filled with a conductor, and the conductor is respectively connected to the gnd of the first metallization layer 301 and the gnd of the second metallization layer 302.

[0065] The embodiment of the present invention also provides an optical module, including the above optical module packaging structure.

[0066] Although the embodiments of the present invention have been disclosed as above, it is not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the field, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details and the embodiments shown and described here.

Claims

1. An optical module packaging structure, characterized in that: include: Printed circuit boards; A bottom plate, which partially overlaps with the printed circuit board, and a plurality of mounting grooves are provided at intervals at the ends of the overlapping portions of the printed circuit board and the bottom plate; The number of EML components is equal to and corresponds to the number of the installation slots, and the EML components include: A chip packaging substrate, which is located in the mounting groove and connected to the bottom plate; An EML laser chip is located in the mounting groove and connected to the chip packaging substrate, the printed circuit board is electrically connected to the EML laser chip through a first differential signal line and a second differential signal line thereon, and the first differential signal line and the second differential signal line form a differential routing; A coupling lens is disposed on the bottom plate and close to the EML laser chip, and is optically aligned and connected with the EML laser chip through active optical coupling; A filter capacitor is disposed on the printed circuit board and is electrically connected to the EML laser chip.

2. The optical module packaging structure according to claim 1, characterized in that: The end of the overlapping portion of the printed circuit board and the bottom plate is a sawtooth structure to form a plurality of the mounting grooves.

3. The optical module packaging structure according to claim 1, characterized in that: The EML component also includes: A connecting substrate, wherein the coupling lens is connected to the bottom plate via the connecting substrate.

4. The optical module packaging structure according to claim 1, characterized in that: The bottom plate is a substrate or a thermoelectric cooler.

5. The optical module packaging structure according to claim 1, characterized in that: The printed circuit board is provided with a plurality of groups of pad assemblies, which are equal in number to and correspond to the EML laser chips, and the EML laser chips are electrically connected to the printed circuit board and the filter capacitor through the pad assemblies.

6. The optical module packaging structure according to claim 5, characterized in that: The chip packaging substrate is provided with a first metallization layer and chip gold-tin solder at one end close to the EML laser chip, and a second metallization layer is provided at one end close to the base plate, the gnd of the first metallization layer is connected to the gnd of the second metallization layer, the EML laser chip is connected to the chip packaging substrate through the chip gold-tin solder, and is electrically connected to the pad assembly through the first metallization layer.

7. The optical module packaging structure according to claim 6, characterized in that: At least one through hole is provided on the chip packaging substrate. The through hole is filled with a conductor, and the conductor is respectively connected to the gnd of the first metallization layer and the gnd of the second metallization layer.

8. The optical module packaging structure according to claim 7, characterized in that: The pad assembly includes a first differential signal line pad, a second differential signal line pad, a filter capacitor pad, a first ground pad and a power pad, the first differential signal line pad is connected to the first differential signal line, the second differential signal line pad is connected to the second differential signal line, and the filter capacitor pad is connected to the filter capacitor; The EML laser chip is provided with an EA signal pad and a laser power supply pad, and the laser power supply pad is connected to the power supply pad; The first metallization layer comprises: A first EA matching RC filter circuit resistor pad, which and the second differential signal line pad are both connected to the EA signal pad; A second EA matching RC filter circuit resistance pad, which is connected to the first EA matching RC filter circuit resistance pad and the filter capacitor pad respectively; A termination resistor pad connected to the first differential signal line pad; The second ground pad is connected to the termination resistor pad and the first ground pad respectively.

9. The optical module packaging structure according to claim 8, characterized in that: The first EA matching RC filter circuit resistance pad and the second EA matching RC filter circuit resistance pad are connected via a first thin film resistor, and the termination resistance pad and the second ground pad are connected via a second thin film resistor.

10. An optical module, characterized in that: It comprises the optical module packaging structure as described in any one of claims 1 to 9.

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