CN215416011U

CN215416011U - Optical module

Info

Publication number: CN215416011U
Application number: CN202122128022.4U
Authority: CN
Inventors: 曲一帆; 张加傲
Original assignee: Hisense Broadband Multimedia Technology Co Ltd
Current assignee: Hisense Broadband Multimedia Technology Co Ltd
Priority date: 2021-09-03
Filing date: 2021-09-03
Publication date: 2022-01-04
Anticipated expiration: 2031-09-03

Abstract

The optical module comprises a circuit board, a signal processing chip and an optical receiving chip, wherein the circuit board comprises a top layer circuit board and an inner layer circuit board, and the signal processing chip is arranged on the top layer circuit board; the top layer circuit board is provided with a mounting groove, the inner layer circuit board comprises an exposed area exposed through the mounting groove, the side surface of the light receiving chip facing the exposed area is provided with a signal bonding pad, and the signal bonding pad is welded with the exposed area; a high-speed signal wire is distributed on the inner layer circuit board, and one end of the high-speed signal wire is connected with the signal bonding pad; and a blind hole is formed between the surface of the top layer circuit board and the inner layer circuit board, and the other end of the high-speed signal line is connected with the signal processing chip through the blind hole. This application sinks the light receiving chip to the inlayer circuit board of circuit board to signal pad through the light receiving chip bottom surface is connected with the inlayer circuit board, and the high-speed signal line is designed with the form of stripline, and it is little to crosstalk and EMI radiation, and the signal passes the impedance homogeneity better, has promoted high-speed signal transmission stability.

Description

Optical module

Technical Field

The application relates to the technical field of optical fiber communication, in particular to an optical module.

Background

With the development of new services and application modes such as cloud computing, mobile internet, video and the like, the development and progress of the optical communication technology become increasingly important. In the optical communication technology, an optical module is a tool for realizing the interconversion of optical signals and is one of key devices in optical communication equipment, and the transmission rate of the optical module is continuously increased along with the development requirement of the optical communication technology.

An optical module generally includes a circuit board and an optical engine (a light emitting module and a light receiving module) electrically connected to the circuit board, and with the wide application of a DSP (Digital Signal processor), the design of the circuit board based on the DSP for high-speed Signal processing is particularly important.

However, due to the space limitation of the circuit board, the high-speed signal lines connected to the light emitting chip and the light receiving chip cannot be designed to be microstrip lines, and the high-speed signal lines need to be replaced to the inner layer of the circuit board, and then replaced to the top layer after a section of strip line is laid on the inner layer of the circuit board, so as to be connected with the bonding pad of the DSP chip, thereby increasing impedance discontinuity points and affecting the signal transmission stability of the high-speed signal lines.

SUMMERY OF THE UTILITY MODEL

The embodiment of the application provides an optical module to solve the problem that high-speed signal transmission is unstable when an optical receiving chip of the existing optical module is connected with a signal processing chip.

The application provides an optical module, includes:

a circuit board;

the signal processing chip is arranged on the circuit board;

the light receiving chip is electrically connected with the circuit board;

wherein, the circuit board includes:

the signal processing chip is arranged on the top circuit board, and is provided with a mounting groove;

the inner-layer circuit board comprises an exposed area exposed through the mounting groove, a signal bonding pad is arranged on the side surface of the light receiving chip facing the exposed area, and the light receiving chip is in contact connection with the exposed area through the signal bonding pad; a high-speed signal wire is distributed on the optical receiver chip, and one end of the high-speed signal wire is connected with a signal bonding pad of the optical receiver chip; and a blind hole is arranged between the high-speed signal line and the surface of the top layer circuit board, and the other end of the high-speed signal line is connected with the signal processing chip through the blind hole.

The optical module comprises a circuit board, a signal processing chip and an optical receiving chip, wherein the circuit board comprises a top layer circuit board and an inner layer circuit board, the signal processing chip is arranged on the top layer circuit board, a mounting groove is formed in the top layer circuit board, the inner layer circuit board comprises an exposed area exposed through the mounting groove, a signal bonding pad is arranged on the side surface, facing the exposed area, of the optical receiving chip, and the optical receiving chip is in contact connection with the exposed area through the signal bonding pad so as to be arranged on the inner layer circuit board; a high-speed signal wire is distributed on the inner layer circuit board, and one end of the high-speed signal wire is connected with a signal bonding pad on the light receiving chip so as to receive a high-speed signal transmitted by the light receiving chip; the blind hole is formed between the surface of the top layer circuit board and the inner layer circuit board, the other end of the high-speed signal line is connected with the signal processing chip through the blind hole, so that high-speed signals transmitted by the high-speed signal line are transmitted to the signal processing chip, and the signal processing chip can process the high-speed signals conveniently. This application sinks the light receiving chip to the inlayer circuit board of circuit board on, and the signal pad of light receiving chip is in the same place with the welding of inlayer circuit board, and the high speed signal line passes through the inlayer circuit board interconnection, can avoid many welding layers, reduces an impedance discontinuity, and the high speed signal line can not receive the EMI radiation interference of external air bed to can improve the signal transmission stability of high speed signal line.

Drawings

Fig. 1 is a schematic diagram of a connection relationship of an optical communication terminal;

FIG. 2 is a schematic diagram of an optical network unit;

fig. 3 is a schematic structural diagram of an optical module according to an embodiment of the present disclosure;

fig. 4 is an exploded structural diagram of an optical module according to an embodiment of the present disclosure;

fig. 5 is an assembly side view of a circuit board, a signal processing chip, and a light receiving chip in an optical module according to an embodiment of the present disclosure;

fig. 6 is a schematic structural diagram of a circuit board in an optical module according to an embodiment of the present disclosure;

fig. 7 is a first schematic cross-sectional structure diagram of a circuit board in an optical module according to an embodiment of the present disclosure;

fig. 8 is a first assembly cross-sectional view of a circuit board, a signal processing chip and a light receiving chip in an optical module according to an embodiment of the present disclosure;

fig. 9 is a routing layout diagram of a top layer of a circuit board in an optical module according to an embodiment of the present application;

fig. 10 is an enlarged schematic view of a top layer of a circuit board in an optical module according to an embodiment of the present disclosure;

fig. 11 is a routing layout diagram of a second layer of a circuit board in an optical module according to an embodiment of the present application;

fig. 12 is a schematic diagram of a second layer of a circuit board in an optical module according to an embodiment of the present disclosure;

fig. 13 is a routing layout diagram of a fourth layer of a circuit board in an optical module according to an embodiment of the present disclosure;

fig. 14 is a schematic diagram of a fourth layer of a circuit board in an optical module according to an embodiment of the present disclosure;

fig. 15 is a schematic cross-sectional structure diagram of a circuit board in an optical module according to an embodiment of the present disclosure;

fig. 16 is a second assembly cross-sectional view of a circuit board, a signal processing chip, and a light receiving chip in an optical module according to an embodiment of the present disclosure;

fig. 17 is a schematic cross-sectional structure diagram of a circuit board in an optical module according to an embodiment of the present application;

fig. 18 is a third assembly cross-sectional view of a circuit board, a signal processing chip, and a light receiving chip in an optical module according to an embodiment of the present disclosure;

fig. 19 is a schematic cross-sectional structure diagram of a circuit board in an optical module according to an embodiment of the present application;

fig. 20 is a fourth assembly cross-sectional view of a circuit board, a signal processing chip, and a light receiving chip in an optical module according to an embodiment of the present disclosure;

fig. 21 is a schematic diagram of a return path of a high-speed signal line in an optical module according to an embodiment of the present disclosure.

Detailed Description

In order to facilitate the technical solution of the present application, some concepts related to the present application will be described below.

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

One of the core links of optical fiber communication is the interconversion of optical and electrical signals. The optical fiber communication uses optical signals carrying information to transmit in information transmission equipment such as optical fibers/optical waveguides, and the information transmission with low cost and low loss can be realized by using the passive transmission characteristic of light in the optical fibers/optical waveguides; meanwhile, the information processing device such as a computer uses an electric signal, and in order to establish information connection between the information transmission device such as an optical fiber or an optical waveguide and the information processing device such as a computer, it is necessary to perform interconversion between the electric signal and the optical signal.

The optical module realizes the function of interconversion of optical signals and electrical signals in the technical field of optical fiber communication, and the interconversion of the optical signals and the electrical signals is the core function of the optical module. The optical module is electrically connected with an external upper computer through a golden finger on an internal circuit board of the optical module, and the main electrical connection comprises power supply, I2C signals, data signals, grounding and the like; the electrical connection mode realized by the gold finger has become the mainstream connection mode of the optical module industry, and on the basis of the mainstream connection mode, the definition of the pin on the gold finger forms various industry protocols/specifications.

Fig. 1 is a schematic diagram of connection relationship of an optical communication terminal. As shown in fig. 1, the connection of the optical communication terminal mainly includes the interconnection among the optical network terminal 100, the optical module 200, the optical fiber 101 and the network cable 103;

one end of the optical fiber 101 is connected with a far-end server, one end of the network cable 103 is connected with local information processing equipment, and the connection between the local information processing equipment and the far-end server is completed by the connection between the optical fiber 101 and the network cable 103; and the connection between the optical fiber 101 and the network cable 103 is made by the optical network terminal 100 having the optical module 200.

An optical port of the optical module 200 is externally accessed to the optical fiber 101, and establishes bidirectional optical signal connection with the optical fiber 101; an electrical port of the optical module 200 is externally connected to the optical network terminal 100, and establishes bidirectional electrical signal connection with the optical network terminal 100; the optical module realizes the interconversion of optical signals and electric signals, thereby realizing the establishment of information connection between the optical fiber and the optical network terminal; specifically, the optical signal from the optical fiber is converted into an electrical signal by the optical module and then input to the optical network terminal 100, and the electrical signal from the optical network terminal 100 is converted into an optical signal by the optical module and input to the optical fiber.

The optical network terminal is provided with an optical module interface 102, which is used for accessing an optical module 200 and establishing bidirectional electric signal connection with the optical module 200; the optical network terminal is provided with a network cable interface 104, which is used for accessing the network cable 103 and establishing bidirectional electric signal connection with the network cable 103; the optical module 200 is connected to the network cable 103 through the optical network terminal 100, specifically, the optical network terminal transmits a signal from the optical module to the network cable and transmits the signal from the network cable to the optical module, and the optical network terminal serves as an upper computer of the optical module to monitor the operation of the optical module.

At this point, a bidirectional signal transmission channel is established between the remote server and the local information processing device through the optical fiber, the optical module, the optical network terminal and the network cable.

Common information processing apparatuses include routers, switches, electronic computers, and the like; the optical network terminal is an upper computer of the optical module, provides data signals for the optical module, and receives the data signals from the optical module, and the common upper computer of the optical module also comprises an optical line terminal and the like.

Fig. 2 is a schematic diagram of an optical network terminal structure. As shown in fig. 2, the optical network terminal 100 has a circuit board 105, and a cage 106 is disposed on a surface of the circuit board 105; an electric connector is arranged in the cage 106 and used for connecting an electric port of an optical module such as a golden finger; the cage 106 is provided with a heat sink 107, and the heat sink 107 has a projection such as a fin that increases a heat radiation area.

The optical module 200 is inserted into the optical network terminal, specifically, the electrical port of the optical module is inserted into the electrical connector inside the cage 106, and the optical port of the optical module is connected to the optical fiber 101.

The cage 106 is positioned on the circuit board, and the electrical connector on the circuit board is wrapped in the cage, so that the electrical connector is arranged in the cage; the optical module is inserted into the cage, held by the cage, and the heat generated by the optical module is conducted to the cage 106 and then diffused by the heat sink 107 on the cage.

Fig. 3 is a schematic view of an optical module according to an embodiment of the present disclosure, and fig. 4 is a schematic view of an exploded structure of an optical module according to an embodiment of the present disclosure. As shown in fig. 3 and 4, an optical module 200 provided in the embodiment of the present application includes an upper housing 201, a lower housing 202, a circuit board 300, an optical sub-module, and an optical fiber adapter.

The upper shell 201 is covered on the lower shell 202 to form a wrapping cavity with two openings; the outer contour of the wrapping cavity is generally a square body, and specifically, the lower shell comprises a main plate and two side plates which are positioned at two sides of the main plate and are perpendicular to the main plate; the upper shell comprises a third shell, and the third shell covers the two side plates of the upper shell to form a wrapping cavity; the upper shell can also comprise two side walls which are positioned on two sides of the third shell and are perpendicular to the third shell, and the two side walls are combined with the two side plates to cover the upper shell on the lower shell.

The two openings may be two ends (204, 205) in the same direction, or two openings in different directions; one opening is an electric port 204, and a gold finger of the circuit board extends out of the electric port 204 and is inserted into an upper computer such as an optical network terminal; the other opening is an optical port 205 for external optical fiber access to connect with an optical sub-module inside the optical module; the circuit board 300, the optical sub-module, the optical fiber adapter and other photoelectric devices are positioned in the packaging cavity.

The assembly mode of combining the upper shell and the lower shell is adopted, so that the circuit board 300, the optical secondary module, the optical fiber adapter and other devices can be conveniently installed in the shell, and the outermost packaging protection shell of the optical module is formed by the upper shell and the lower shell; the upper shell and the lower shell are made of metal materials generally, so that electromagnetic shielding and heat dissipation are facilitated; generally, the housing of the optical module is not made into an integrated component, so that when devices such as a circuit board and the like are assembled, the positioning component, the heat dissipation component and the electromagnetic shielding component cannot be installed, and the production automation is not facilitated.

The optical module 200 provided in the embodiment of the present application further includes an unlocking component, which is located on an outer wall of the package cavity/lower housing 202, and is used to realize a fixed connection between the optical module and the upper computer, or release the fixed connection between the optical module and the upper computer.

The unlocking component is provided with a clamping component matched with the upper computer cage; the end of the unlocking component can be pulled to enable the unlocking component to move relatively on the surface of the outer wall; the optical module is inserted into a cage of the upper computer, and the optical module is fixed in the cage of the upper computer by a clamping component of the unlocking component; by pulling the unlocking component, the clamping component of the unlocking component moves along with the unlocking component, so that the connection relation between the clamping component and the upper computer is changed, the clamping relation between the optical module and the upper computer is released, and the optical module can be drawn out from the cage of the upper computer.

The circuit board 300 is provided with circuit traces, electronic components (such as capacitors, resistors, triodes, and MOS transistors), and chips (such as an MCU, a laser driver chip, a limiting amplifier chip, a clock data recovery CDR, a power management chip, and a data processing chip DSP). The circuit board connects the electrical appliances in the optical module together according to the circuit design through circuit wiring to realize the functions of power supply, electrical signal transmission, grounding and the like.

The circuit board is generally a hard circuit board, and the hard circuit board can also realize a bearing effect due to the relatively hard material of the hard circuit board, for example, the hard circuit board can stably bear a chip; when the optical transceiver is positioned on the circuit board, the rigid circuit board can also provide stable bearing; the hard circuit board can also be inserted into an electric connector in the upper computer cage, and specifically, a metal pin/golden finger is formed on the surface of the tail end of one side of the hard circuit board and is used for being connected with the electric connector; these are not easily implemented with flexible circuit boards.

A flexible circuit board is also used in a part of the optical module to supplement a rigid circuit board; the flexible circuit board is generally used in combination with a rigid circuit board, for example, the rigid circuit board may be connected to the optical transceiver device through the flexible circuit board.

In this embodiment, the optical subassembly includes the tosa 400 and the tosa, the tosa generally includes an optical receiver chip, the tosa may include a detector and a transimpedance amplifier, both the detector and the transimpedance amplifier are disposed on the circuit board, the detector is connected to the transimpedance amplifier via a high-speed Signal line to transmit the converted electrical Signal to the transimpedance amplifier for amplitude limiting and amplification, the transimpedance amplifier is connected to a Signal processing chip (DSP) 310 to transmit the amplified electrical Signal to the DSP chip 310, and the DSP chip 310 processes the electrical Signal. For an optical module with a high transmission rate, such as an 800G optical module, the rosa includes a first rosa 500 and a second rosa 600, the first rosa 500 includes a first detector and a first transimpedance amplifier, the second rosa 600 includes a second detector and a second transimpedance amplifier, a high-speed signal line connecting the first transimpedance amplifier and the DSP chip 310, and a high-speed signal line connecting the second transimpedance amplifier and the DSP chip 310 are usually designed in a microstrip line form, and the high-speed signal line is directly connected from a DSP pad to signal pads of the first transimpedance amplifier and the second transimpedance amplifier.

However, due to the space limitation of the circuit board 300, the high-speed signal line connecting the first transimpedance amplifier and the DSP chip 310 and the high-speed signal line connecting the second transimpedance amplifier and the DSP chip 310 may not be all designed in a microstrip line form, and a part of the high-speed signal line needs to be replaced to the inner layer of the circuit board 300, and then replaced to the top layer of the circuit board 300 after a section of strip line is walked, so that impedance discontinuity is increased, and the stability of the high-speed signal line for transmitting a high-speed signal is affected.

In order to solve the above problem, in the present application, the transimpedance amplifier of the optical receive sub-module is sunk to the inner layer of the circuit board 300, and the high-speed signal line is arranged in the inner layer of the circuit board 300 in a strip line manner, so as to prevent the high-speed signal line from being connected to the DSP chip 310 by replacing the layer, thereby avoiding replacing the layer more than once, reducing an impedance discontinuity point, and ensuring the stability of high-speed signal transmission.

Fig. 5 is an assembly side view of a circuit board, a signal processing chip, and a light receiving chip in an optical module according to an embodiment of the present disclosure, and fig. 6 is a schematic structural diagram of the circuit board in the optical module according to the embodiment of the present disclosure. As shown in fig. 5 and 6, in the optical module provided in the embodiment of the present application, a first mounting groove 320 and a second mounting groove 330 are disposed on a circuit board 300, the first mounting groove 320 and the second mounting groove 330 extend from a top layer of the circuit board 300 to an inner layer of the circuit board 300, and a first transimpedance amplifier 510 of a first optical receive sub-module 500 is embedded in the first mounting groove 320, so that the first transimpedance amplifier 510 is disposed on the inner layer of the circuit board 300 through the first mounting groove 320; the second transimpedance amplifier 610 of the second rosa 600 is embedded in the second mounting groove 330, so that the second transimpedance amplifier 610 is disposed on the inner layer of the circuit board 300 through the second mounting groove 330.

After the first transimpedance amplifier 510 is embedded in the first mounting groove 320, the signal pad of the first transimpedance amplifier 510 is also arranged in the inner layer of the circuit board 300, so that the first transimpedance amplifier 510 is conveniently connected with the strip line arranged on the inner layer of the circuit board 300 through the signal pad; after the second transimpedance amplifier 610 is embedded in the second mounting groove 330, the signal pad of the second transimpedance amplifier 610 is also disposed in the inner layer of the circuit board 300, so that the second transimpedance amplifier 610 is conveniently connected to the strip line disposed on the inner layer of the circuit board 300 through the signal pad.

A plurality of high-speed signal lines are distributed on the inner layer of the circuit board 300 in a strip line manner, one ends of the plurality of high-speed signal lines are connected with the signal bonding pad of the first transimpedance amplifier 510 and the signal bonding pad of the second transimpedance amplifier 610, and the other ends of the plurality of high-speed signal lines are connected with the DSP chip 310 on the top layer of the circuit board 300, so that the high-speed signals output by the transimpedance amplifiers are transmitted to the DSP chip 310 through the high-speed signal lines, and the DSP chip 310 can process the high-speed signals conveniently.

In this embodiment, the tosa 400 includes a laser chip, a collimating lens and a coupling lens, where the laser chip emits a laser beam, the laser beam is converted into a collimated beam by the collimating lens, and the collimated beam is converged to the fiber adapter by the coupling lens to implement emission of light. The circuit board 300 may be provided with a mounting groove in which the laser chip is embedded, the mounting groove extending from the top layer of the circuit board 300 to the inner layer thereof, and the laser chip being embedded in the mounting groove to be disposed on the inner layer of the circuit board 300 through the mounting groove.

After the laser chip is embedded in the mounting groove of the circuit board 300, the routing bonding pad of the laser chip is also arranged in the inner layer of the circuit board 300, so that the laser chip is conveniently connected with the strip line arranged on the inner layer of the circuit board 300 through the routing bonding pad. The inner layer of the circuit board 300 is provided with a plurality of high-speed signal lines in a strip line form, one ends of the plurality of high-speed signal lines are connected with the routing bonding pads of the laser chip, and the other ends of the high-speed signal lines are connected with the DSP chip 310 on the top layer of the circuit board 300, so that high-speed signals output by the DSP chip 310 are transmitted to the laser chip through the high-speed signal lines to drive the laser chip to emit laser beams.

In order to facilitate connection of the high-speed signal line arranged on the inner layer of the circuit board 300 with the DSP chip 310, a blind hole is formed between the top layer and the inner layer of the circuit board 300, a DSP bonding pad is arranged on the side face, in contact with the top layer of the circuit board 300, of the DSP chip 310, the DSP bonding pad is connected with one end of the blind hole, the other end of the high-speed signal line is connected with the blind hole, the high-speed signal line is connected with the DSP bonding pad through the blind hole, and therefore high-speed signals transmitted by the high-speed signal line are transmitted to the DSP chip 310.

Fig. 7 is a first schematic cross-sectional structure diagram of a circuit board in an optical module according to an embodiment of the present disclosure, and fig. 8 is a first assembly cross-sectional view of the circuit board, a signal processing chip, and a light receiving chip in the optical module according to the embodiment of the present disclosure. As shown in fig. 7 and 8, the circuit board 300 includes a top layer circuit board 301 and an inner layer circuit board, the inner layer circuit board and the top layer circuit board 301 are stacked, a mounting groove is provided on the top layer circuit board 301, the inner layer circuit board includes an exposed area exposed through the mounting groove, a signal pad is provided on a side surface of the transimpedance amplifier facing the exposed area, the transimpedance amplifier is in contact connection with the exposed area of the inner layer circuit board through the signal pad, so as to dispose the transimpedance amplifier on the inner layer circuit board of the circuit board 300 and be exposed through the mounting groove. A high-speed signal line is arranged on an inner-layer circuit board of the circuit board 300, and one end of the high-speed signal line is connected with a signal pad of the transimpedance amplifier; a blind hole is formed between the surface of the top circuit board of the circuit board 300 and the inner circuit board, and the other end of the high-speed signal line is connected with the DSP chip 310 through the blind hole.

The inner layer circuit board can be a second layer circuit board 302, that is, the circuit board 300 includes a top layer circuit board 301 and a second layer circuit board 302, the top layer circuit board 301 and the second layer circuit board 302 are adjacent and stacked, a mounting groove 3012 is provided on the top layer circuit board 301, the second layer circuit board 302 includes an exposed area 3025 exposed through the mounting groove 3012, a signal pad is provided on a side surface of the transimpedance amplifier facing the exposed area 3025, the transimpedance amplifier is in contact connection with the exposed area 3025 of the second layer circuit board 302 through the signal pad, so as to place the transimpedance amplifier on the second layer circuit board 302 of the circuit board 300; when the transimpedance amplifier is placed in the mounting slot 3012, the transimpedance amplifier may protrude from the top-layer circuit board 301 through the mounting slot 3012.

A first blind hole 340 is arranged between the surface of the top layer circuit board 301 and the second layer circuit board 302, a DSP pad on the top layer circuit board 301 is connected with one end of the first blind hole 340, a high-speed signal line is arranged on the second layer circuit board 302, one end of the high-speed signal line is connected with a signal pad of the transimpedance amplifier, and the other end of the high-speed signal line is connected with the other end of the first blind hole 340, so that the transimpedance amplifier is connected with the DSP chip 310 through the high-speed signal line and the first blind hole 340.

Fig. 9 is a top-layer routing layout diagram of a circuit board in an optical module according to an embodiment of the present application, and fig. 10 is a top-layer partially enlarged schematic view of the circuit board in the optical module according to the embodiment of the present application. As shown in fig. 9 and 10, a top layer circuit board 301 of the circuit board 300 is provided with a DSP pad 3011 corresponding to the Rx pad of the DSP chip 310, and the DSP pad 3011 is soldered to the Rx pad of the DSP chip 310 to electrically connect the DSP chip 310 to the circuit board 300. The transimpedance amplifier is connected to the Rx pad through a high-speed signal line arranged on the second-layer circuit board 302, so that the high-speed signal connection between the transimpedance amplifier and the DSP chip 310 is realized.

Tx pads, Rx pads on the DSP chip 310 may be disposed on the left side of the bottom surface (the side facing the circuit board 300) of the DSP chip 310 to facilitate signal connection of the DSP chip 310 to a transimpedance amplifier or a laser chip located on the left side of the DSP chip 310. An output bonding pad can be arranged on the right side of the bottom surface of the DSP chip 310, one end of a high-speed signal wire arranged on the top layer circuit board 301 is connected with the output bonding pad, and the other end of the high-speed signal wire is connected with a golden finger on the circuit board 300, so that an electric signal processed by the DSP chip 310 is transmitted to the golden finger through the high-speed signal wire; or the electric signal received by the golden finger is transmitted to the DSP chip 310 through the high-speed signal line, and the electric signal is transmitted to the laser chip through the high-speed signal line arranged on the second layer circuit board 302, so as to drive the laser chip to emit a laser beam.

Fig. 11 is a routing layout diagram of a second-layer circuit board of a circuit board in an optical module according to an embodiment of the present disclosure, and fig. 12 is a schematic diagram of a local enlargement of the second-layer circuit board of the circuit board in the optical module according to the embodiment of the present disclosure. As shown in fig. 11 and 12, the transimpedance amplifier is disposed on an exposed area 3025 of the second-layer circuit board 302 exposed through the mounting slot 3012, a first pad 3021 is disposed on the second-layer circuit board 302, and the first pad 3021 is disposed corresponding to the DSP pad 3011 on the top-layer circuit board 301, so that the first pad 3021 is conveniently connected to the DSP pad 3011 through the first blind hole 340. The signal pad of the transimpedance amplifier is connected to the first pad 3021 through the high-speed signal line arranged on the second-layer circuit board 302, so that the transimpedance amplifier is connected to the DSP chip 310 through the high-speed signal line and the first blind via.

In the embodiment of the present application, the high-speed signal line is designed in the form of a strip line on the second-layer circuit board 302, and compared with a microstrip line, the strip line is not interfered by EMI radiation on the external air layer, and does not radiate out energy, which is beneficial to EMC. The high-speed signal lines are interconnected through the second-layer circuit board 302, so that the phenomenon that layers are changed for one time is avoided, and one impedance discontinuous point is reduced, so that the impedance uniformity is better.

When the high-speed signal line is designed in a strip line form on the second layer circuit board 302, the strip line type high-speed signal line can avoid a dispensing area of the transimpedance amplifier case, and the influence of glue on the impedance of the high-speed signal line is avoided.

In order to form a signal loop with the high-speed signal line on the second-layer circuit board 302, a reference ground plane is disposed above the second-layer circuit board 302, a first ground line is disposed on the reference ground plane, and the first ground line and the high-speed signal line on the second-layer circuit board 302 form a loop path, so that the transmission stability of the high-speed signal on the second-layer circuit board 302 is ensured.

In this embodiment, the inner layer circuit board may further include a second layer circuit board 302, a third layer circuit board 303, and a fourth layer circuit board 304, that is, the circuit board 300 includes a top layer circuit board 301, a second layer circuit board 302, a third layer circuit board 303, and a fourth layer circuit board 304, the top layer circuit board 301, the second layer circuit board 302, the third layer circuit board 303, and the fourth layer circuit board 304 are sequentially stacked, that is, the second layer circuit board 302 is disposed below the top layer circuit board 301 and is disposed adjacent to the top layer circuit board 301; the third layer of circuit board 303 is arranged below the second layer of circuit board 302 and is arranged adjacent to the second layer of circuit board 302; the fourth-layer wiring board 304 is disposed below the third-layer wiring board 303, and is disposed adjacent to the third-layer wiring board 303.

The top layer circuit board 301 is provided with a mounting groove 3012, the second layer circuit board 302 comprises an exposed area 3025 exposed through the mounting groove 3012, a signal pad is arranged on the side of the transimpedance amplifier facing the exposed area 3025, and the transimpedance amplifier is in contact connection with the exposed area 3025 of the second layer circuit board 302 through the signal pad so as to be arranged on the second layer circuit board 302; a first bonding pad 3021 is arranged on the second-layer circuit board 302, and a signal bonding pad of the transimpedance amplifier is connected with the first bonding pad 3021 through a high-speed signal line on the second-layer circuit board 302.

A first blind hole 340 is arranged between the surface of the top layer circuit board 301 and the second layer circuit board 302, a first pad 3021 is arranged corresponding to the first blind hole 340, a DSP pad 3011 on the top layer circuit board 301 is connected with one end of the first blind hole 340, and the first pad 3021 is connected with the other end of the first blind hole 340. The transimpedance amplifier is connected with the DSP chip 310 through a high-speed signal line on the second-layer circuit board 302, a first bonding pad 3021, a first blind via 340, and a DSP bonding pad 3011 on the top-layer circuit board 301.

For the 800G optical module, since there are many receiving optical paths of the optical receive sub-module, if only the second layer of circuit board 302 is used to transmit high-speed signals, there are many high-speed signal lines arranged on the second layer of circuit board 302, which may cause high-speed signal crosstalk, so that the high-speed signal lines may also be arranged on the fourth layer of circuit board 304, and the high-speed signals are transmitted through the second layer of circuit board 302 and the fourth layer of circuit board 304 together.

In order to facilitate the arrangement of the high-speed signal line on the fourth-layer circuit board 304 for transmitting a high-speed signal, a second pad 3022 is further disposed on the second-layer circuit board 302, the signal pad of the transimpedance amplifier is connected to the second pad 3022 through the high-speed signal line arranged on the second-layer circuit board 302, and the second pad 3022 is connected to the fourth-layer circuit board 304 through a blind via.

In the embodiment of the present application, the first pad 3021 and the second pad 3022 on the second layer of circuit board 302 are not located on the same straight line, that is, the distance between the first pad 3021 and the transimpedance amplifier and the distance between the second pad 3022 and the transimpedance amplifier are not the same, for example, the distance between the first pad 3021 and the transimpedance amplifier is greater than the distance between the second pad 3022 and the transimpedance amplifier, so as to prevent the high-speed signal line connected to the first pad 3021 from affecting the high-speed signal line connected to the second pad 3022.

Fig. 13 is a routing layout diagram of a fourth layer of circuit board in an optical module according to an embodiment of the present application, and fig. 14 is a schematic partial enlarged view of the fourth layer of circuit board in the optical module according to the embodiment of the present application. As shown in fig. 13 and 14, a third pad 3041 and a fourth pad 3042 are disposed on the fourth-layer circuit board 304, the third pad 3041 is disposed corresponding to the second pad 3022 on the second-layer circuit board 302, the fourth pad 3042 is disposed corresponding to the DSP pad 3011 on the top-layer circuit board 301, and the third pad 3041 is connected to the fourth pad 3042 via a high-speed signal line disposed on the fourth-layer circuit board 304.

A second blind hole is formed between the second-layer circuit board 302 and the fourth-layer circuit board 304, the second pad 3022 is connected to one end of the second blind hole, and the third pad 3041 is connected to the other end of the second blind hole, so that the second pad 3022 on the second-layer circuit board 302 is connected to the third pad 3041 on the fourth-layer circuit board 304 through the second blind hole.

A third blind hole is formed between the surface of the top-layer circuit board 301 and the fourth-layer circuit board 304, the DSP pad 3011 is connected to one end of the third blind hole, and the fourth pad 3042 is connected to the other end of the third blind hole, so that the DSP pad 3011 on the top-layer circuit board 301 is connected to the fourth pad 3042 on the fourth-layer circuit board 304 through the third blind hole.

When the transimpedance amplifier is placed in the mounting groove, a signal bonding pad can be arranged on the side, facing the inner layer of the circuit board 300, of the transimpedance amplifier and connected with the high-speed signal line on the inner layer of the circuit board 300 through the signal bonding pad, a routing bonding pad can be arranged on the side, facing away from the inner layer of the circuit board 300, of the transimpedance amplifier, and the routing bonding pad is connected with the high-speed signal line on the inner layer of the circuit board 300 through routing.

Fig. 15 is a second cross-sectional structural view of the circuit board in the optical module according to the embodiment of the present application, and fig. 16 is a second assembly cross-sectional view of the circuit board, the signal processing chip, and the light receiving chip in the optical module according to the embodiment of the present application. As shown in fig. 15 and 16, the circuit board 300 includes a top layer circuit board 301 and an inner layer circuit board, the inner layer circuit board and the top layer circuit board 301 are stacked, a first groove 3013 is formed on the top layer circuit board 301, a second groove is formed on the inner layer circuit board, and the first groove 3013 is communicated with the second groove; the inner layer circuit board comprises an exposed area exposed through the first groove 3013 and the second groove and a routing connection area exposed through the first groove 3013, and thus the length size of the first groove 3013 is larger than that of the second groove 3023.

The transimpedance amplifier is arranged on the exposed area, a routing bonding pad is arranged on the side surface of the transimpedance amplifier, which is back to the exposed area, and the routing bonding pad is connected with a routing connecting area through routing; a blind hole is arranged between the surface of the top layer circuit board 301 and the inner layer circuit board, and a high-speed signal wire connected with the routing connection area is connected with the DSP chip 310 through the blind hole.

The inner layer circuit board may include a second layer circuit board 302 and a third layer circuit board 303, that is, the circuit board 300 includes a top layer circuit board 301, a second layer circuit board 302 and a third layer circuit board 303, and the top layer circuit board 301, the second layer circuit board 302 and the third layer circuit board 303 are sequentially stacked. The top layer circuit board 301 is provided with a first groove 3013, the second layer circuit board 302 is provided with a second groove 3023, the first groove 3013 is communicated with the second groove 3023, and the length of the first groove 3013 is greater than that of the second groove 3023.

The third layer circuit board 303 includes a first exposed region 3031 exposed through the first recess 3013 and the second recess 3023, and one side (the side facing the first exposed region 3031) of the transimpedance amplifier is disposed on the first exposed region 3031.

The second layer of circuit board 302 comprises a routing connection region 3024 exposed through the first groove 3013, a routing pad is arranged on the side of the transimpedance amplifier facing away from the first exposed region 3031, and the routing pad is connected with the routing connection region 3024 through routing; the second layer of circuit board 302 is provided with a high speed signal line, a routing pad of the transimpedance amplifier is connected with a routing connection area 3024 through routing, and the routing connection area 3024 is connected with one end of the high speed signal line.

A first blind hole 340 is arranged between the surface of the top layer circuit board 301 and the second layer circuit board 302, and the DSP pad 3011 on the top layer circuit board 301 is connected with the first blind hole 340; the second layer of circuit board 302 is provided with a first bonding pad 3021, the first bonding pad 3021 is disposed corresponding to the first blind via 340, one end of the high-speed signal line on the second layer of circuit board 302 is connected to the wire bonding connection area 3024, and the other end is connected to the first bonding pad 3021, so that the transimpedance amplifier is connected to the high-speed signal line, the first bonding pad 3021, the first blind via 340 and the DSP chip 310 through the wire bonding pad and the wire bonding connection area 3024 on the second layer of circuit board 302.

After the transimpedance amplifier is disposed on the first exposed region 3031, according to the actual size of the transimpedance amplifier, the side of the transimpedance amplifier facing away from the first exposed region 3031 may protrude from the second-layer circuit board 302, be flush with the second-layer circuit board 302, or be recessed in the second-layer circuit board 302, as long as the wire bonding pad on the transimpedance amplifier can be connected to the wire bonding connection region on the second-layer circuit board 302 through a wire bonding.

If one side of the transimpedance amplifier is disposed on the first exposed region 3031 and the other side protrudes from the second-layer circuit board 302, in order to shorten the routing length between the routing pad on the transimpedance amplifier and the routing connection region 3024 on the second-layer circuit board 302, a groove may be dug in the third-layer circuit board 303 below the second-layer circuit board 302 to reduce the height difference between the routing pad on the transimpedance amplifier and the second-layer circuit board 302.

Fig. 17 is a third schematic cross-sectional structure diagram of a circuit board in an optical module according to an embodiment of the present disclosure, and fig. 18 is a third assembly cross-sectional view of the circuit board, a signal processing chip, and a light receiving chip in the optical module according to the embodiment of the present disclosure. As shown in fig. 17 and 18, the circuit board 300 includes a top layer circuit board 301, a second layer circuit board 302, and a third layer circuit board 303, which are sequentially stacked, where the top layer circuit board 301 is provided with a first recess 3013, the second layer circuit board 302 is provided with a second recess 3023, the third layer circuit board 303 is provided with a third recess 3032, the third recess 3032 does not penetrate through the third layer circuit board 303, and the first recess 3013, the second recess 3023, and the third recess 3032 are communicated. The length dimension of the first recess 3013 is greater than the length dimension of the second recess 3023, and the length dimension of the second recess 3023 may be the same as the length dimension of the third recess 3032.

The third layer circuit board 303 includes a second exposed region 3033 exposed by the first recess 3013, the second recess 3023, and the third recess 3032, and a side surface of one side (facing the second exposed region 3033) of the transimpedance amplifier is disposed on the second exposed region 3033.

The second layer of circuit board 302 includes a routing connection region 3024 exposed through the first groove 3013, and a routing pad is disposed on a side of the transimpedance amplifier facing away from the second exposed region 3033, and is connected to the routing connection region 3024 through routing. The second layer of circuit board 302 is provided with a high speed signal line, a routing pad of the transimpedance amplifier is connected with a routing connection area 3024 through routing, and the routing connection area 3024 is connected with one end of the high speed signal line.

Fig. 19 is a fourth schematic cross-sectional view of a circuit board in an optical module according to an embodiment of the present disclosure, and fig. 20 is a fourth cross-sectional view of an assembly of the circuit board, a signal processing chip, and a light receiving chip in the optical module according to the embodiment of the present disclosure. As shown in fig. 19 and fig. 20, the inner layer circuit board may further include a second layer circuit board 302, a third layer circuit board 303 and a fourth layer circuit board 304, that is, the circuit board 300 includes a top layer circuit board 301, a second layer circuit board 302, a third layer circuit board 303 and a fourth layer circuit board 304, and the top layer circuit board 301, the second layer circuit board 302, the third layer circuit board 303 and the fourth layer circuit board 304 are sequentially stacked.

The top layer circuit board 301 is provided with a first groove 3013, the second layer circuit board 302 is provided with a second groove 3023, the third layer circuit board 303 is provided with a fourth groove 3034, the first groove 3013 and the second groove 3023 are communicated with the fourth groove 3034, the length of the first groove 3013 is greater than the length of the second groove 3023, and the length of the second groove 3023 can be the same as the length of the fourth groove 3034.

The fourth-layer circuit board 304 includes a third exposed region 3043 exposed through the first recess 3013, the second recess 3023, and the fourth recess 3034, a signal pad is disposed on a side of the transimpedance amplifier facing the third exposed region 3043, the transimpedance amplifier is in contact connection with the third exposed region 3043 through the signal pad, and the signal pad of the transimpedance amplifier is connected to the high-speed signal line disposed on the fourth-layer circuit board 304.

A third blind hole 350 is formed between the surface of the top-layer circuit board 301 and the fourth-layer circuit board 304, a fourth pad 3042 is formed on the fourth-layer circuit board 304, and the fourth pad 3042 corresponds to the third blind hole 350. One end of the high-speed signal line on the fourth-layer circuit board 304 is connected to a signal pad of the transimpedance amplifier, and the other end of the high-speed signal line is connected to a fourth pad 3042, and the fourth pad 3042 is connected to the DSP pad 3011 on the top-layer circuit board 301 through the third blind via 350, so that the transimpedance amplifier is connected to the DSP chip 310 through the signal pad, the high-speed signal line on the fourth-layer circuit board 304, the fourth pad 3042, and the third blind via 350.

In the embodiment of the present application, the second layer of circuit board 302 includes a wire bonding area 3024 exposed through the first groove 3013, and a wire bonding pad is disposed on a side of the transimpedance amplifier facing away from the third exposed area 3043, and the wire bonding pad is connected to the wire bonding area 3024 through a wire bonding. The second layer of circuit board 302 is also provided with a high speed signal line, the transimpedance amplifier is connected with a routing connection area 3024 through routing, and the routing connection area 3024 is connected with one end of the high speed signal line so as to transmit a high speed signal through the second layer of circuit board 302.

A first blind hole 340 is arranged between the surface of the top layer circuit board 301 and the second layer circuit board 302, a first pad 3021 is arranged on the second layer circuit board 302, and the first pad 3021 is arranged corresponding to the first blind hole 340. One end of the high-speed signal line on the second layer circuit board 302 is connected with the routing connection area 3024, the other end is connected with the first bonding pad 3021, the first bonding pad 3021 is connected with the DSP bonding pad 3011 on the top layer circuit board 301 through the first blind hole 340, so that the transimpedance amplifier is connected with the high-speed signal line, the first bonding pad 3021, the first blind hole 340 and the DSP chip 310 through the routing bonding pad, the routing connection area 3024 on the second layer circuit board 302.

Therefore, the transimpedance amplifier is connected with the high-speed signal line on the fourth-layer circuit board 304 through the signal bonding pad arranged on one side and connected with the high-speed signal line on the second-layer circuit board 302 through the routing bonding pad arranged on the other side, so that the high-speed signal is transmitted through the second-layer circuit board 302 and the fourth-layer circuit board 304 together, and the high-speed transmission efficiency of the transimpedance amplifier is improved.

Fig. 21 is a schematic return path diagram of a high-frequency signal high-speed signal line in an optical module according to an embodiment of the present application. As shown in fig. 21, in order to form a signal loop with the high-speed signal lines on the second-layer circuit board 302 and the fourth-layer circuit board 304, a second ground line is provided on the third-layer circuit board 303 between the second-layer circuit board 302 and the fourth-layer circuit board 304, the high-speed signal lines on the second-layer circuit board 302 and the second ground line form a return path, and the high-speed signal lines on the fourth-layer circuit board 304 and the second ground line form a return path. The second layer circuit board 302 and the fourth layer circuit board 304 form a backflow path through the third layer circuit board 303 between the two layers, so that magnetic flux cancellation is achieved, and EMI is reduced.

According to maxwell's equations, all electrical and magnetic effects between separate charged bodies or currents, whether they are vacuum or solid matter, are transmitted through the intermediate region between them, and the magnetic flux always propagates in the transmission line in the circuit board.

The optical module provided by the embodiment of the application comprises a circuit board, a DSP chip and an optical receiving chip, wherein the circuit board comprises a top layer circuit board and an inner layer circuit board which is stacked with the top layer circuit board, and the DSP chip is arranged on the top layer circuit board; the top layer circuit board is provided with a mounting groove, the inner layer circuit board comprises an exposed area exposed through the mounting groove, a signal bonding pad can be arranged on the side surface of the light receiving chip facing the exposed area, and the light receiving chip is in contact connection with the exposed area through the signal bonding pad; a high-speed signal wire is distributed on the inner layer circuit board, and one end of the high-speed signal wire is connected with a signal bonding pad on the light receiving chip so as to receive a high-speed signal transmitted by the light receiving chip; the top layer circuit board is provided with the blind hole between the inlayer circuit board and the top layer circuit board, and the other end of high speed signal line passes through the blind hole and is connected with the DSP chip to high speed signal transmission with high speed signal line transmission to the DSP chip makes things convenient for the DSP signal to handle high speed signal. One side of the light receiving chip can be arranged on the exposed area, the other side of the light receiving chip is provided with a routing pad, a groove communicated with the mounting groove is arranged on the inner-layer circuit board, the inner-layer circuit board comprises the exposed area exposed through the mounting groove and the groove and a routing connection area exposed through the mounting groove, the routing pad on the light receiving chip is connected with the routing connection area through routing, and a high-speed signal wire connected with the routing connection area is connected with the DSP chip through a blind hole. This application sinks the light receiving chip to the inlayer circuit board of circuit board on, light receiving chip accessible signal pad is connected with high-speed signal line, also accessible routing pad and high-speed signal line routing connection, high-speed signal line passes through the inlayer circuit board and interconnects with the stripline form, can avoid more reprinting, reduce an impedance discontinuity, and compare in the microstrip line, the high-speed signal line of stripline form can not receive the EMI radiation interference of outside air aspect, also can not radiate away the energy, be good to EMC, make the crosstalk of high-speed signal line, EMI radiates for a short time, the impedance homogeneity is better, thereby greatly promoted the signal transmission stability of high-speed signal line.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.

Claims

1. A light module, comprising:

a circuit board;

the signal processing chip is arranged on the circuit board;

the light receiving chip is electrically connected with the circuit board;

wherein, the circuit board includes:

2. The optical module according to claim 1, wherein the inner layer wiring board comprises a second layer wiring board, the second layer wiring board comprises an exposed area exposed through the mounting groove, a signal pad is disposed on a side of the light receiving chip facing the exposed area, a first pad is disposed on the second layer wiring board, and the signal pad of the light receiving chip is connected to the first pad through the high speed signal line; a first blind hole is formed between the surface of the top layer circuit board and the second layer circuit board, a first bonding pad is arranged corresponding to the first blind hole, and the first bonding pad is connected with the signal processing chip through the first blind hole.

3. The optical module according to claim 2, wherein a reference ground plane is disposed above the second-layer circuit board, and a first ground line is disposed on the reference ground plane, and the first ground line and the high-speed signal line on the second-layer circuit board form a return path.

4. The optical module according to claim 1, wherein the inner layer circuit board comprises a second layer circuit board, a third layer circuit board and a fourth layer circuit board, and the top layer circuit board, the second layer circuit board, the third layer circuit board and the fourth layer circuit board are sequentially stacked;

the second layer of circuit board comprises an exposed area exposed through the mounting groove, a signal bonding pad is arranged on the side surface of the light receiving chip facing the exposed area, a first bonding pad and a second bonding pad are arranged on the second layer of circuit board, and the signal bonding pad of the light receiving chip is connected with the first bonding pad through the high-speed signal wire; a first blind hole is formed between the surface of the top layer circuit board and the second layer circuit board, the first bonding pad is arranged corresponding to the first blind hole, and the first bonding pad is connected with the signal processing chip through the first blind hole;

and the signal bonding pad of the light receiving chip is connected with the second bonding pad through a high-speed signal wire, and the second bonding pad is connected with the fourth layer circuit board.

5. The optical module according to claim 4, wherein a second blind via is disposed between the second layer circuit board and the fourth layer circuit board, and a third pad is disposed on the fourth layer circuit board, and the second pad is connected to the third pad through the second blind via.

6. The optical module according to claim 5, wherein a fourth pad is further provided on the fourth layer of wiring board, and the third pad is connected to the fourth pad through a high speed signal line provided on the fourth layer of wiring board;

and a third blind hole is formed between the surface of the top layer circuit board and the fourth layer circuit board, a fourth bonding pad is arranged corresponding to the third blind hole, and the fourth bonding pad is connected with the signal processing chip through the third blind hole.

7. The optical module according to claim 6, wherein a second ground line is provided on the third layer of wiring board, the high speed signal line on the second layer of wiring board forms a return path with the second ground line, and the high speed signal line on the fourth layer of wiring board forms a return path with the second ground line.

8. The optical module according to claim 4, wherein a distance between the first pad and the light receiving chip and a distance between the second pad and the light receiving chip are different.

9. The optical module according to claim 8, wherein a distance between the first pad and the light receiving chip is larger than a distance between the second pad and the light receiving chip.

10. The optical module of claim 1, wherein the high-speed signal line is arranged on the inner layer circuit board in a strip line form.