CN217693343U

CN217693343U - Optical module

Info

Publication number: CN217693343U
Application number: CN202221457024.6U
Authority: CN
Inventors: 杨世海; 张洪浩; 刘飞; 张强; 赵其圣
Original assignee: Hisense Broadband Multimedia Technology Co Ltd
Current assignee: Hisense Broadband Multimedia Technology Co Ltd
Priority date: 2022-06-10
Filing date: 2022-06-10
Publication date: 2022-10-28
Anticipated expiration: 2032-06-10

Abstract

The application discloses optical module includes: the lower shell and the upper shell cover a packaging cavity formed. The circuit board is arranged inside the wrapping cavity. The substrate is provided with: the first grounding conductive area is connected with a grounding signal wire on the circuit board; a first resistor is arranged between the first resistor pad and the first grounding conductive area; a second resistor is arranged between the second resistor pad and the first grounding conductive area; be equipped with the EML laser instrument on the first ground connection conducting region, the EML laser instrument includes: a ground pad, an electro-absorption modulation pad and a light emitting pad; the grounding bonding pad is connected with the first grounding conductive area, the electroabsorption modulation bonding pad is connected with the first resistance bonding pad, and the signal wire is connected; the light-emitting pad is connected with a power supply pin of the circuit board. The circuit board is provided with a first differential driving signal line connected with the signal line; and the second differential driving signal line is connected with the second resistance bonding pad, so that the matching of the differential driving signal output by the driving chip and the single-ended driving of the EML laser is realized.

Description

Optical module

Technical Field

The application relates to the technical field of 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.

Along with the gradual rise of the speed, the differential drive has stronger driving capability, strong anti-interference capability and accurate time sequence positioning, and differential signal transmission is adopted in signal transmission. However, the EML laser adopts single-end driving, and the driving signal output by the driving chip is a differential signal, so that the driving chip cannot drive the EML laser.

SUMMERY OF THE UTILITY MODEL

The application provides an optical module to realize the matching of a differential drive signal output by a drive chip and the single-ended drive of an EML laser.

In order to solve the technical problem, the embodiment of the application discloses the following technical scheme:

the embodiment of the application discloses an optical module, includes:

an upper housing;

the lower shell is covered with the upper shell to form a wrapping cavity;

the circuit board is arranged inside the packaging cavity;

the surface of the substrate is provided with a first grounding conductive area, a first resistance pad, a second resistance pad and a signal wire, and the first grounding conductive area is connected with a grounding signal wire on the circuit board;

a first resistor is arranged between the first resistor pad and the first grounding conductive area;

a second resistor is arranged between the second resistor pad and the first grounding conductive area;

the circuit board is provided with a first differential driving signal line and a second differential driving signal line; the first differential driving signal line is connected with the signal line; the second differential driving signal line is connected with the second resistance pad;

an EML laser is disposed on the first ground conductive region, the EML laser including: a ground pad, an electro-absorption modulation pad, and a light-emitting pad;

the ground pad is connected to the first ground conductive region, the electroabsorption modulation pad is connected to the first resistance pad, and the electroabsorption modulation pad is connected to the signal line.

The beneficial effect of this application:

the application discloses optical module includes: the lower shell and the upper shell cover to form a wrapping cavity. The circuit board is arranged inside the wrapping cavity. The substrate includes: the circuit board comprises a first grounding conductive area, a first resistance pad, a second resistance pad and a signal wire. The first grounding conductive area is connected with a grounding signal wire on the circuit board; a first resistor is arranged between the first resistor pad and the first grounding conductive area; a second resistor is arranged between the second resistor pad and the first grounding conductive area; an EML laser is disposed on the first ground conductive region, the EML laser including: a ground pad, an electro-absorption modulation pad and a light emitting pad; the ground pad is connected with the first ground conductive region, the electroabsorption modulation pad is connected with the first resistance pad, and the electroabsorption modulation pad is connected with the signal line; the light-emitting bonding pad is connected with a power supply pin of the circuit board. This application is favorable to reducing the space occupancy through setting up the second resistance in ceramic substrate surface, improves the degree of integrating. The circuit board is provided with a first differential driving signal line and a second differential driving signal line; the first differential driving signal line is connected with the signal line; and the second differential driving signal line is connected with the second resistance bonding pad, so that the matching of the differential driving signal output by the driving chip and the single-end driving of the EML laser is realized.

Drawings

In order to more clearly illustrate the technical solutions in the present disclosure, the drawings needed to be used in some embodiments of the present disclosure will be briefly described below, and it is apparent that the drawings in the following description are only drawings of some embodiments of the present disclosure, and other drawings can be obtained by those skilled in the art according to the drawings. Furthermore, the drawings in the following description may be regarded as schematic diagrams, and do not limit the actual size of products, the actual flow of methods, the actual timing of signals, and the like, involved in the embodiments of the present disclosure.

FIG. 1 is a connection diagram of an optical communication system according to some embodiments;

FIG. 2 is a block diagram of an optical network terminal according to some embodiments;

FIG. 3 is a block diagram of a light module according to some embodiments;

FIG. 4 is an exploded view of a light module according to some embodiments;

fig. 5 is an exploded schematic view of a light emitting device according to an embodiment of the present disclosure;

fig. 6 is a schematic view of another exploded structure of a light emitting device provided in an embodiment of the present application;

fig. 7 is a schematic partial structure diagram of a light emitting device according to an embodiment of the present application;

fig. 8 is a first schematic view illustrating a top surface structure of a ceramic substrate according to an embodiment of the present disclosure;

fig. 9 is a second schematic view illustrating a top surface structure of a ceramic substrate according to an embodiment of the present disclosure;

FIG. 10 is a cross-sectional view of a ceramic substrate according to an embodiment of the present disclosure;

FIG. 11 is a first schematic view illustrating the connection between a ceramic substrate and a circuit board according to an embodiment of the present disclosure;

fig. 12 is a second schematic view illustrating a connection between a ceramic substrate and a circuit board according to an embodiment of the present application.

Detailed Description

Technical solutions in some embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present disclosure, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments provided by the present disclosure belong to the protection scope of the present disclosure.

In an optical communication system, an optical signal is used to carry information to be transmitted, and the optical signal carrying the information is transmitted to information processing equipment such as a computer through information transmission equipment such as an optical fiber or an optical waveguide, so as to complete information transmission. Since light has a passive transmission characteristic when transmitted through an optical fiber or an optical waveguide, low-cost and low-loss information transmission can be realized. Since a signal transmitted by an information transmission device such as an optical fiber or an optical waveguide is an optical signal and a signal that can be recognized and processed by an information processing device such as a computer is an electrical signal, it is necessary to perform interconversion between the electrical signal and the optical signal 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.

The optical module realizes the function of interconversion between the optical signal and the electrical signal in the technical field of optical communication. The optical module comprises an optical port and an electrical port, the optical module realizes optical communication with information transmission equipment such as optical fibers or optical waveguides and the like through the optical port, realizes electrical connection with an optical network terminal (such as an optical modem) through the electrical port, and the electrical connection is mainly used for power supply, I2C signal transmission, data information transmission, grounding and the like; the optical network terminal transmits the electric signal to the information processing equipment such as a computer through a network cable or a wireless fidelity (Wi-Fi).

Fig. 1 is a connection diagram of an optical communication system. As shown in fig. 1, the optical communication system includes a remote server 1000, a local information processing device 2000, an optical network terminal 100, an optical module 200, an optical fiber 101, and a network cable 103.

One end of the optical fiber 101 is connected to the remote server 1000, and the other end is connected to the optical network terminal 100 through the optical module 200. The optical fiber itself can support long-distance signal transmission, for example, signal transmission of thousands of meters (6 km to 8 km), on the basis of which if a repeater is used, theoretically infinite distance transmission can be realized. Therefore, in a typical optical communication system, the distance between the remote server 1000 and the optical network terminal 100 may be several kilometers, tens of kilometers, or hundreds of kilometers.

One end of the network cable 103 is connected to the local information processing device 2000, and the other end is connected to the optical network terminal 100. The local information processing apparatus 2000 may be any one or several of the following apparatuses: router, switch, computer, cell-phone, panel computer, TV set etc..

The physical distance between the remote server 1000 and the optical network terminal 100 is greater than the physical distance between the local information processing apparatus 2000 and the optical network terminal 100. The connection between the local information processing apparatus 2000 and the remote server 1000 is made by the optical fiber 101 and the network cable 103; and the connection between the optical fiber 101 and the network cable 103 is completed by the optical module 200 and the optical network terminal 100.

The optical module 200 includes an optical port configured to access the optical fiber 101 and an electrical port, so that the optical module 200 establishes a bidirectional optical signal connection with the optical fiber 101; the electrical port is configured to be accessed into the optical network terminal 100, so that the optical module 200 establishes a bidirectional electrical signal connection with the optical network terminal 100. The optical module 200 converts an optical signal and an electrical signal to each other, so that an information connection is established between the optical fiber 101 and the optical network terminal 100. For example, an optical signal from the optical fiber 101 is converted into an electrical signal by the optical module 200 and then input to the optical network terminal 100, and an electrical signal from the optical network terminal 100 is converted into an optical signal by the optical module 200 and input to the optical fiber 101. Since the optical module 200 is a tool for implementing the interconversion between the optical signal and the electrical signal, and has no function of processing data, information is not changed in the above-mentioned photoelectric conversion process.

The optical network terminal 100 includes a housing (housing) having a substantially rectangular parallelepiped shape, and an optical module interface 102 and a network cable interface 104 provided on the housing. The optical module interface 102 is configured to access the optical module 200, so that the optical network terminal 100 establishes a bidirectional electrical signal connection with the optical module 200; the network cable interface 104 is configured to access the network cable 103 such that the optical network terminal 100 establishes a bi-directional electrical signal connection with the network cable 103. The optical module 200 is connected to the network cable 103 via the optical network terminal 100. For example, the optical network terminal 100 transmits the electrical signal from the optical module 200 to the network cable 103, and transmits the electrical signal from the network cable 103 to the optical module 200, so that the optical network terminal 100 can monitor the operation of the optical module 200 as an upper computer of the optical module 200. The upper computer of the Optical module 200 may include an Optical Line Terminal (OLT) and the like in addition to the Optical network Terminal 100.

The remote server 1000 establishes a bidirectional signal transmission channel with the local information processing device 2000 through the optical fiber 101, the optical module 200, the optical network terminal 100, and the network cable 103.

Fig. 2 is a configuration diagram of the optical network terminal, and fig. 2 only shows a configuration of the optical module 200 of the optical network terminal 100 in order to clearly show a connection relationship between the optical module 200 and the optical network terminal 100. As shown in fig. 2, the optical network terminal 100 further includes a circuit board 105 disposed within the housing, a cage 106 disposed on a surface of the circuit board 105, a heat sink 107 disposed on the cage 106, and an electrical connector disposed inside the cage 106. The electrical connector is configured to access an electrical port of the optical module 200; the heat sink 107 has a projection such as a fin that increases a heat radiation area.

The optical module 200 is inserted into a cage 106 of the optical network terminal 100, the cage 106 holds the optical module 200, and heat generated by the optical module 200 is conducted to the cage 106 and then diffused by a heat sink 107. After the optical module 200 is inserted into the cage 106, the electrical port of the optical module 200 is connected to the electrical connector inside the cage 106, so that the optical module 200 is connected to the optical network terminal 100 by a bidirectional electrical signal. Further, the optical port of the optical module 200 is connected to the optical fiber 101, and the optical module 200 establishes bidirectional optical signal connection with the optical fiber 101.

FIG. 3 is a block diagram of a light module according to some embodiments. As shown in fig. 3, the optical module 200 includes a housing (shell), a circuit board 300 disposed in the housing, and an optical transceiver module 400.

The shell comprises an upper shell 201 and a lower shell 202, wherein the upper shell 201 is covered on the lower shell 202 to form the shell with two openings; the outer contour of the housing generally appears square.

In some embodiments of the present disclosure, the lower housing 202 includes a bottom plate and two lower side plates 2022 located at both sides of the bottom plate and disposed perpendicular to the bottom plate; the upper case 201 includes a cover 2011, and the cover 2011 covers the two lower side plates 2022 of the lower case 202 to form the above case.

In some embodiments, the lower housing 202 includes a bottom plate 2021 and two lower side plates 2022 located at both sides of the bottom plate 2021 and disposed perpendicular to the bottom plate 2021; the upper housing 201 includes a cover 2011 and two upper side plates located on two sides of the cover 2011 and perpendicular to the cover 2011, and the two upper side plates are combined with the two lower side plates 2022 to cover the upper housing 201 on the lower housing 202.

The direction of the connecting line of the two

openings

204 and 205 may be the same as the length direction of the optical module 200, or may not be the same as the length direction of the optical module 200. For example, the opening 204 is located at an end portion (right end in fig. 3) of the optical module 200, and the opening 205 is also located at an end portion (left end in fig. 3) of the optical module 200. Alternatively, the opening 204 is located at an end of the optical module 200, and the opening 205 is located at a side of the optical module 200. The opening 204 is an electrical port, and a gold finger of the circuit board 300 extends out of the electrical port 204 and is inserted into an upper computer (for example, the optical network terminal 100); the opening 205 is an optical port configured to access the external optical fiber 101, so that the external optical fiber 101 is connected to the optical transceiver module 400 inside the optical module 200.

The upper shell 201 and the lower shell 202 are combined to facilitate the installation of the components such as the circuit board 300 and the optical transceiver module 400 into the shells, and the upper shell 201 and the lower shell 202 form encapsulation protection for the components. In addition, when the components such as the circuit board 300 and the optical transceiver module 400 are assembled, the positioning components, the heat dissipation components and the electromagnetic shielding components of the components are convenient to arrange, and the automatic production is facilitated.

In some embodiments, the upper housing 201 and the lower housing 202 are generally made of metal materials, which is beneficial to achieve electromagnetic shielding and heat dissipation.

In some embodiments, the optical module 200 further includes an unlocking component located outside its housing, and the unlocking component 203 is configured to implement a fixed connection between the optical module 200 and an upper computer or release the fixed connection between the optical module 200 and the upper computer.

Illustratively, the unlocking member is located on the outer wall of the two lower side plates 2022 of the lower housing 202, and has a snap-fit member that matches with a cage of the upper computer (e.g., the cage 106 of the optical network terminal 100). When the optical module 200 is inserted into the cage of the upper computer, the optical module 200 is fixed in the cage of the upper computer by the engaging member of the unlocking member; when the unlocking member is pulled, the engaging member of the unlocking member moves along with the unlocking member, and further the connection relationship between the engaging member and the upper computer is changed, so that the engagement relationship between the optical module 200 and the upper computer is released, and the optical module 200 can be drawn out from the cage of the upper computer.

The circuit board 300 includes circuit traces, electronic components, and chips, and the electronic components and the chips are connected together by the circuit traces according to a circuit design to implement functions of power supply, electrical signal transmission, grounding, and the like. Examples of the electronic components include capacitors, resistors, transistors, and Metal-Oxide-Semiconductor Field-Effect transistors (MOSFETs). The chip includes, for example, a Micro Controller Unit (MCU), a laser driver chip, a limiting amplifier (limiting amplifier), a Clock and Data Recovery (CDR) chip, a power management chip, and a Digital Signal Processing (DSP) chip.

The circuit board 300 is generally a rigid circuit board, which can also perform a bearing function due to its relatively rigid material, for example, the rigid circuit board can stably bear the electronic components and chips; when the optical transceiver component is positioned on the circuit board, the rigid circuit board can also provide smooth bearing; the rigid circuit board can also be inserted into an electric connector in the cage of the upper computer.

The circuit board 300 further includes a gold finger formed on an end surface thereof, the gold finger being composed of a plurality of pins independent of each other. The circuit board 300 is inserted into the cage 106 and electrically connected to the electrical connector in the cage 106 by gold fingers. The gold fingers may be disposed on only one side of the circuit board 300 (e.g., the upper surface shown in fig. 4), or may be disposed on both upper and lower sides of the circuit board 300, so as to adapt to the situation where the requirement of the number of pins is large. The golden finger is configured to establish an electrical connection with the upper computer to realize power supply, grounding, I2C signal transmission, data signal transmission and the like.

Of course, a flexible circuit board is also used in some optical modules. Flexible circuit boards are generally used in conjunction with rigid circuit boards to supplement the rigid circuit boards. For example, a flexible circuit board may be used to connect the rigid circuit board and the optical transceiver module.

The optical transceiver component 400 includes a light emitting device configured to enable emission of an optical signal and a light receiving device configured to enable reception of the optical signal. Illustratively, the light emitting device and the light receiving device are combined together to form an integrated light transceiving component.

Fig. 5 is an exploded schematic view of a light emitting device according to an embodiment of the present disclosure; fig. 6 is a schematic diagram of another exploded structure of a light emitting device provided in an embodiment of the present application; the following describes an overall structure of a light emitting section of an optical module according to the present invention with reference to fig. 5 and 6. As shown in fig. 5 and 6, the light emitting device includes a cover plate 401 and a housing 402, the cover plate 401 and the housing 402 are coupled to each other, and specifically, the cover plate 401 covers the housing 402 from above, one side wall of the housing 402 has an opening 404 for insertion of the circuit board 300, and the other side wall of the housing 402 has a through hole for insertion of the fiber optic adapter 403.

Specifically, the circuit board 300 extends into the housing 402 through the opening 404, and the circuit board 300 is fixed to the lower case 202; the circuit board 300 is plated with metal traces, and the optical device can be electrically connected to the corresponding metal traces by wire bonding, so as to electrically connect the optical device inside the housing 402 and the circuit board 300.

The signal light emitted by the light emitting device is emitted into the through hole, the optical fiber adapter 403 extends into the through hole 405 to be coupled and received with the signal light, the assembling structure design can enable the optical fiber adapter 403 to move back and forth in the through hole 405, the required size of the optical fiber between the light emitting device and the optical fiber plug can be adjusted, and when the optical fiber is short, the optical fiber adapter can be moved backwards (towards the outer direction of the cavity) in the through hole to meet the requirement of the connection size; when the optical fiber is longer, the optical fiber adapter can be moved forwards (towards the inner direction of the cavity) in the through hole so as to straighten the optical fiber and avoid bending the optical fiber. The fiber optic adapter 403 is inserted into the through hole to achieve fixation with the light emitting device; during assembly, the fiber optic adapters 403 may be moved within the through-holes to select a fixed position.

One side wall of the housing 402 has an opening 404 for insertion of the circuit board 300 and the other side wall of the housing 402 has a through hole for insertion of the fiber optic adapter 403.

In this embodiment, the optical device disposed in the housing 402 may optionally be connected to the circuit board 300 through a pin, where the pin is designed to have a shape adapted to the lower housing, one end of the pin is inserted into the lower housing, and a metal trace is plated on the end of the pin, the optical device may be electrically connected to the corresponding metal trace in a wire bonding manner, one end of the pin disposed in the housing 402 is provided with a plurality of pins electrically connected to the metal trace, the pins are inserted into the circuit board 300 and are welded together, thereby achieving electrical connection between the optical device in the housing 402 and the circuit board 300, and of course, the pins on the pins may also be directly welded to the circuit board 300, so as to achieve electrical connection between the optical device in the housing 402 and the circuit board 300.

In the signal transmission process, the optical transmission subassembly 500 in the housing 402 receives the electrical signal transmitted from the circuit board 300, converts the electrical signal into an optical signal, and then transmits the optical signal to the outside of the optical module after entering the optical fiber adapter 403.

The light emitting device has a package structure TO package laser chips and the like, and the existing package structures include a coaxial package TO-CAN, a silicon optical package, a chip-on-board LENS assembly package COB-LENS and a micro-optical XMD package. The package is further divided into hermetic package and non-hermetic package, which provides a stable and reliable working environment for the laser chip on one hand and forms external electrical connection and optical output on the other hand.

Depending on the product design and process, the optical module may be packaged differently to make the light emitting device. The laser chip has vertical cavity surface light emitting and edge light emitting, and the different light emitting directions of the laser chip can influence the selection of the packaging form. The various packages have obvious technical differences, whether they are different from the structure or from the process, and those skilled in the art know that although different packages achieve the same purpose, different packages belong to different technical routes, and different packaging technologies do not give technical suggestions to each other.

Fig. 7 is a schematic partial structure diagram of a light emitting device according to an embodiment of the present disclosure; as shown in fig. 7, the light emitting subassembly 500 in the embodiment of the present application includes: the substrate 501 is disposed in the housing 402 and is made of alumina ceramic, aluminum nitride ceramic, or the like. The ceramic substrate 501 has functional circuits engraved on its surface for the transmission of signals, such as the transmission line 502. The surface of the ceramic substrate 501 is provided with an EML laser 503, the EML laser 503 is an integrated device of a laser DFB and an electric absorption modulator EA, the laser DFB converts an electric signal into an optical signal, and the electric absorption modulator EA outputs the optical signal after coding modulation, so that the output optical signal carries information. The EML laser 503 is provided with a light emitting pad, an electro-absorption modulation pad, and a ground pad, the ground pad is provided on the lower surface of the EML laser 503, and the light emitting pad and the electro-absorption modulation pad are provided on the upper surface of the EML laser 503.

Fig. 8 is a first schematic view of a top surface structure of a ceramic substrate according to an embodiment of the present disclosure, and fig. 9 is a second schematic view of a top surface structure of a ceramic substrate according to an embodiment of the present disclosure. Where fig. 9 is a diagram after the surface mounting of the electric device in fig. 8, as shown in fig. 8, the first ground conductive region 5011 is provided on the upper surface of the ceramic substrate, and the first ground conductive region 5011 is provided with a first avoidance portion 50111, a second avoidance portion 50112, a third avoidance portion 50113, and a fourth avoidance portion 50114. The first ground conductive area 5011 is provided with a first escape portion 50111, and the first escape portion 50111 is provided with an opening in which the signal line 5012 is provided. The first grounded conductive area 5011 forms a wrap around trend to the signal line in this application, providing a return ground for the information carried in the signal line 5012, which is beneficial for reducing signal noise.

The first ground conductive region 5011 is provided with a second escape portion 50112 in which a first resistance pad 5013 is provided, and a certain gap is provided between the first resistance pad 5013 and the first ground conductive region 5011. A first resistor 504 is disposed between the first resistor pad 5013 and the first ground conductive region 5011. For the convenience of preparation, the first resistor 504 has an impedance matching function, and finally, the impedance output by the EML laser is consistent with the characteristic impedance, so that the first thin film resistor can be called as a matching resistor; since the space of the ceramic substrate is small, the first resistor 504 is generally a thin film resistor, which is formed by sintering a region of the ceramic substrate.

The first ground conductive area 5011 is provided with a third escape portion 50113 in which a second resistance pad 5015 is provided, with a certain gap between the second resistance pad 5015 and the first ground conductive area 5011. A second resistor 505 is disposed between the second resistor pad 5015 and the first ground conductive region 5011. For the convenience of preparation, the second resistor 505 has an impedance matching function, and finally, the impedance output by the EML laser is consistent with the characteristic impedance, so the second resistor 505 can be referred to as a matching resistor; since the space of the ceramic substrate is small, the second resistor 505 is generally a thin film resistor, which is formed by sintering one area of the ceramic substrate.

The first ground conductive region 5011 is provided with a fourth escape 50114 in which a power supply relay pad 5014 is provided. The EML laser 503 includes: an electro-absorption modulation pad 5031, a light emitting pad 5032 and a ground pad. The electroabsorption modulation pad 5031 is connected with the first resistor pad 5013 by wire bonding. Generally, a first conductive line is disposed between the electro-absorption modulation pad 5031 and the first resistor pad 5013, and the first conductive line may be a gold line, a silver line, or a metal line made of other conductive materials. In order to prolong the service life of the optical module and avoid unstable performance of the metal wire caused by the environment such as temperature, humidity and the like, the first lead is a gold wire.

In the present application, the first escape portion 50111 and the third escape portion 50113 communicate with each other. The first escape portion 50111 and the third escape portion 50113 may or may not communicate with each other.

The electro-absorption modulation pad 5031 is also connected to a signal line. In this application, a second conductive line is disposed between the electro-absorption modulation pad 5031 and the signal line, and the second conductive line may be a gold line, a silver line, or a metal line made of other conductive materials. In order to prolong the service life of the optical module and avoid unstable performance of the metal wire caused by the environment such as temperature, humidity and the like, the second wire is a gold wire.

With the above arrangement, the first resistance pad 5013 is connected to the signal line via the first conductive line, the electro-absorption modulation pad 5031, and the second conductive line. One end of the first resistor 504 is connected to the first resistor pad 5013, and the other end of the first resistor 504 is connected to the first ground conductive area 5011.

The ground pad of the EML laser 503 is connected to the first ground conductive area 5011, and specifically, the ground pad of the EML laser 503 is connected to the first ground conductive area 5011 by a conductive paste or solder.

A second conductive line is provided between the electroabsorption modulation pad 5031 and the signal line, the ground pad of the EML laser is connected to the first ground conductive area 5011, and in conjunction with the provision of the first resistor 504, the first resistor 504 is connected in parallel to the electroabsorption modulation region of the EML laser, and the first resistor 504 has a function of resistance matching.

When the optical module sends a signal, a gold finger introduces an electrical signal into the laser driver chip, the laser driver chip transmits the electrical signal to the EML laser, and then the EML laser 503 converts the electrical signal into an optical signal, wherein the laser driver chip is connected with the EML laser 5033 through a wire, the wire has a certain characteristic impedance, because of the rated impedance output by the laser driver chip, when the impedance output by the EML laser 503 is not matched with the characteristic impedance, the transmission signal between the laser driver chip and the laser is lost, and the integrity of the signal is reduced, so in order to ensure the integrity of the signal, it is necessary to ensure that the impedance output by the EML laser is matched with the characteristic impedance, and it should be noted that the matching means that the impedance value output by the EML laser reaches the characteristic impedance value, that is, the impedance value output by the EML laser is consistent with the characteristic impedance value. The first resistor 504 is connected in parallel with the electro-absorption modulation region of the EML laser so that the resistance value of the EML laser output is consistent with the characteristic resistance value.

The light emitting pads 5032 of the EML laser 503 are connected to the power supply relay pads 5014. The light emitting pad 5032 of the EML laser 503 and the power supply relay pad 5014 are connected by a third wire. The third wire can be a gold wire, a silver wire or a metal wire made of other conductive materials. In order to prolong the service life of the optical module and avoid unstable performance of the metal wire caused by the environment such as temperature, humidity and the like, the third wire is a gold wire.

The power transfer pad 5014 also has power pin connections on the circuit board to provide power to the EML laser. The power supply adapter pad 5014 is arranged between the power supply pin of the circuit board and the light emitting pad 5032 of the EML laser, the power supply pin of the circuit board and the light emitting pad 5032 of the EML laser are electrically connected in two sections, a fourth wire is arranged between the power supply pin and the power supply adapter pad 5014, and the light emitting pad 5032 is connected with the power supply adapter pad 5014 through a third wire, so that collapse caused by overlong conduction between the power supply pin and the light emitting pad 5032 of the EML laser is avoided, and the stability of the optical module is improved.

Fig. 10 is a schematic cross-sectional view of a ceramic substrate according to an embodiment of the present disclosure. Referring to fig. 10, the ceramic substrate 501 has a first sub-ceramic substrate 510 and a second sub-ceramic substrate 520 stacked on each other, wherein the first sub-ceramic substrate 510 is disposed above the second sub-ceramic substrate, and a second ground conductive region 530 is disposed between the first sub-ceramic substrate 510 and the second sub-ceramic substrate 520 and is a signal return layer. In order to connect the first ground conductive area 5011 and the second ground conductive area 530, one or more through holes 540 are disposed on the first sub-ceramic substrate 510, and one end of each through hole is connected to the first ground conductive area 5011, and the other end is connected to the second ground conductive area.

In the embodiment of the application, in order to facilitate the connection of the wires, signal connection pads are arranged at two ends of the signal wire on the ceramic substrate and used for routing. Specifically, a first end of the signal wire is provided with a first signal pad, a second end of the signal wire is provided with a second signal pad, and a signal connecting wire is arranged between the first signal pad and the second signal pad. The width of the first signal pad is larger than that of the signal connecting line, and the width of the second signal pad is larger than that of the signal connecting line.

The circuit board is provided with a ground pin, which is connected to the first ground conductive area 5011 by a wire. The position of the lead between the circuit board and the ceramic substrate should be shortened as much as possible to reduce the loss.

Fig. 11 is a first schematic view illustrating a connection between a ceramic substrate and a circuit board according to an embodiment of the present disclosure. As shown in fig. 11, the present application provides an example that the driving signal output by the laser driving chip is a differential signal, and the circuit board is provided with a first differential driving signal line 301 and a second differential driving signal line 302. The first differential driving signal line 301 is connected to a signal line 5012 on the ceramic substrate, and the second differential driving signal line 302 is connected to a second resistance pad 5015. The ground signal line 303 is connected to the first ground conductive region 5011.

In the application example, the first differential driving signal line 301 is connected to a first end of a signal line, and a signal carried therein is transmitted to a second end of the signal line 5012 via the first end of the signal line 5012. A second end of the signal line is connected to the electro-absorption modulation pad 5031 of the EML laser. The second differential driving signal line 302 is connected to a second resistance pad 5015, and a second resistor 505 is provided between the second resistance pad 5015 and the first ground conductive area 5011. The signal in the first differential driving signal line 301 is transmitted to the electroabsorption modulation pad 5031 via the signal line, and the signal in the second differential driving signal line 302 is connected to the ground pad of the EML laser via the second resistor pad 5015, the second resistor 505, and the first ground conductive region 5011.

The first differential driving signal line 301 and the second differential driving signal line 302 have the same width and the same length. The first differential driving signal line 301 is further connected to a driving chip 305, and the second differential driving signal line 302 is further connected to the driving chip 305. The first end of the first differential driving signal line 301 is connected with the driving chip 305, and the second end of the first differential driving signal line 301 is connected with the first end of the signal line 5012 in a routing manner; the first end of the second differential driving signal line 302 is connected to the driver chip 305, and the second end of the second differential driving signal line 302 is connected to the first end of the second resistor pad 5015 by wire bonding. In order to reduce the length difference between the differential driving signal lines, ensure the continuity of impedance and reduce the reflection of signals, the first end of the first differential driving signal line 301 is flush with the first end of the second differential driving signal line 302; the second end of the first differential drive signal line 301 is disposed flush with the second end of the second differential drive signal line 302. The second resistance pad 5015 is spaced apart from the second end of the second differential driving signal line 302 by a distance equal to the minimum distance between the first ground conductive region 5011 and the second end of the first differential driving signal line 301. A conductive line between the first ground conductive region 5011 and the second end of the first differential driving signal line 301 is disposed at the shortest distance between the first ground conductive region 5011 and the first differential driving signal line 301.

The power transfer pad 5014 also has power pin connections 304 on the circuit board to provide power to the EML laser. The power supply adapter pad 5014 is arranged between the power supply pin of the circuit board and the light emitting pad 5032 of the EML laser, the power supply pin of the circuit board and the light emitting pad 5032 of the EML laser are electrically connected in two sections, a fourth wire is arranged between the power supply pin and the power supply adapter pad 5014, and the light emitting pad 5032 is connected with the power supply adapter pad 5014 through a third wire, so that collapse caused by overlong conduction between the power supply pin and the light emitting pad 5032 of the EML laser is avoided, and the stability of the optical module is improved.

Fig. 12 is a second schematic view illustrating connection between a ceramic substrate and a circuit board according to an embodiment of the present disclosure. As shown in fig. 12, the present application also provides another example, if the driving signal output by the laser driving chip is a single-ended signal, the circuit board is provided with a driving signal line 306, and the driving signal line is connected to a signal line on the ceramic substrate. The second resistance pad 5015 is not connected to the circuit board.

Since the above embodiments are all described by referring to and combining with other embodiments, the same portions are provided between different embodiments, and the same and similar portions between the various embodiments in this specification may be referred to each other. And will not be described in detail herein.

It is noted that, in this specification, relational terms such as "first" and "second," and the like, are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a circuit structure, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such circuit structure, article, or apparatus. Without further limitation, having an element defined by the phrase "comprising a … …" does not exclude the presence of another like element in a circuit structure, article, or device that comprises the element.

Other embodiments of the present application will be apparent to those skilled in the art from consideration of the specification and practice of the present disclosure. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the application and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the application being indicated by the following claims.

The above-described embodiments of the present application do not limit the scope of the present application.

Claims

1. A light module, comprising: an upper housing;

the lower shell is covered with the upper shell to form a wrapping cavity;

the circuit board is arranged inside the packaging cavity;

a first resistor connected across the first resistor pad and the first ground conductive region;

a second resistor connected across the second resistor pad and the first ground conductive region;

an EML laser is disposed on the first ground conductive region, the EML laser including: a ground pad, an electro-absorption modulation pad and a light emitting pad;

2. The optical module according to claim 1, wherein a driving chip is disposed on the circuit board, and the driving chip is connected to the first differential driving signal line and the second differential driving signal line; the first end of the first differential driving signal wire is connected with the driving chip, and the second end of the first differential driving signal wire is connected with the signal wire in a routing way;

the first end of the second differential driving signal wire is connected with the driving chip, and the first end of the second differential driving signal wire is connected with the second resistance pad in a routing mode.

3. The optical module of claim 1, wherein a minimum distance between the second resistive pad and the second differential driving signal line is equal to a minimum distance between the first differential driving signal line and the signal line.

4. The optical module according to claim 1, wherein the first resistor is a thin film resistor, and the second resistor is a thin film resistor.

5. The optical module according to claim 1, wherein the first ground conductive area is provided with a first avoidance portion, the signal line is provided in the first avoidance portion, the first ground conductive area is further provided with a third avoidance portion, the second resistance pad is provided in the third avoidance portion, and the first avoidance portion is communicated with the third avoidance portion.

6. The optical module according to claim 5, wherein the first ground conductive area is further provided with a second relief, and the first resistor pad is disposed in the second relief.

7. The optical module according to claim 1, wherein the first ground conductive area is further provided with a fourth avoiding portion, and a power supply adapter pad is arranged in the fourth avoiding portion;

the light emitting pad is connected with the power supply transfer pad.

8. The optical module of claim 1, wherein the substrate comprises:

a first sub-substrate;

the first grounding conductive area is arranged on the upper surface of the second sub-substrate;

and the second grounding conductive area is arranged between the first sub-substrate and the second sub-substrate, and the first grounding conductive area is connected with the second grounding conductive area through a through hole.

9. The optical module of claim 1, wherein a ground pin is disposed on the circuit board and connected to the first ground conductive region.

10. The optical module according to claim 1, wherein the first end of the signal line is provided with a first signal pad connected to the circuit board;

a second signal bonding pad is arranged at the second end of the signal wire and connected with the electro-absorption modulation bonding pad;

the first grounding conductive area is arranged around three sides of the signal wire, and an opening is arranged at the second end of the signal wire.