CN117706703A

CN117706703A - An optical module

Info

Publication number: CN117706703A
Application number: CN202211091560.3A
Authority: CN
Inventors: 张加傲; 王欣南; 王彦波; 邵宇辰; 慕建伟
Original assignee: Hisense Broadband Multimedia Technology Co Ltd
Current assignee: Hisense Broadband Multimedia Technology Co Ltd
Priority date: 2022-09-07
Filing date: 2022-09-07
Publication date: 2024-03-15
Also published as: CN118974616A; WO2024051129A1

Abstract

The application provides an optical module, which comprises a circuit board, a laser driving chip, a laser and a heating resistor, wherein the laser driving chip, the laser and the heating resistor are arranged on the circuit board; the circuit board comprises a first heat transfer layer, a second heat transfer layer and a filling layer positioned between the first heat transfer layer and the second heat transfer layer, a gap is formed between the upper surface of the first heat transfer layer and the laser driving chip, the laser is arranged on the first heat transfer layer, and the heat of the heating resistor is conducted to the laser through the first heat transfer layer; the second heat transfer layer is positioned below the first heat transfer layer, a plurality of through holes are arranged between the second heat transfer layer and the first heat transfer layer, and the second heat transfer layer is connected with the laser through the through holes. The first and second heat transfer layers connected through the via holes are arranged on the circuit board, the laser is located on the first heat transfer layer, heat of the heating resistor is conducted to the laser through the first and second heat transfer layers, so that the heating resistor is conducted to the laser to be more in heat, and heat transfer efficiency is faster.

Description

Optical module

Technical Field

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

Background

With the development of new business and application modes such as cloud computing, mobile internet, video and the like, the development and progress of optical communication technology become more and more important. In the optical communication technology, the optical module is a tool for realizing the mutual conversion of optical signals, is one of key devices in optical communication equipment, and the transmission rate of the optical module is continuously improved along with the development of the optical communication technology.

The optical module generally comprises a circuit board and a laser mounted on the circuit board, wherein the working temperature of the laser is 15-75 ℃, and the heat dissipation of the optical module is not concerned in most cases under the low temperature condition. In use, when the optical module is in a low-temperature environment, such as an industrial low-temperature environment (-40 ℃), the laser is affected by the low-temperature environment, and performance cracking of the laser, such as optical power drop, spectral shift, bandwidth reduction of the laser, and the like, often occur, so that the optical module cannot work normally.

Disclosure of Invention

The embodiment of the application provides an optical module, which is used for realizing the heating of a laser in the optical module under a low-temperature environment and maintaining the working temperature of the laser, so as to avoid the adverse effect of the low-temperature environment on the performance of the laser.

The application provides a circuit board, including:

a circuit board;

the laser driving chip is arranged on the circuit board;

the laser is adhered to the circuit board, and the top surface of the laser is electrically connected with the laser driving chip through wire bonding;

the heating resistor is electrically connected with the circuit board and is used for heating the laser at low temperature;

wherein, the circuit board includes:

the first heat transfer layer is positioned on the upper surface of the circuit board and is provided with a gap with the laser driving chip; the laser is arranged on the first heat transfer layer, and the heating resistor is positioned above the first heat transfer layer; for conducting heat generated by the heating resistor to the laser;

the second heat transfer layer is positioned below the first heat transfer layer, a plurality of through holes are arranged between the second heat transfer layer and the first heat transfer layer, and the second heat transfer layer is connected with the laser through the through holes; for conducting heat conducted via the via to the laser;

and the filling layer is positioned between the first heat transfer layer and the second heat transfer layer and is used for connecting the first heat transfer layer and the second heat transfer layer.

As can be seen from the above embodiments, the optical module provided in the embodiments of the present application includes a circuit board, a laser driving chip, a laser and a heating resistor, where the circuit board includes a first heat transfer layer, a second heat transfer layer and a filling layer, the first heat transfer layer is located on an upper surface of the circuit board, the laser driving chip is disposed on the upper surface of the circuit board, and a gap is formed between the first heat transfer layer and the laser driving chip, so as to avoid connection between the first heat transfer layer and the laser driving chip, and thus avoid heat conduction to the laser driving chip; the laser is stuck on the first heat transfer layer, and a bonding pad on the top surface of the laser is electrically connected with the laser driving chip through wire bonding so as to generate an optical signal according to driving current provided by the laser driving chip; the heating resistor is positioned above the first heat transfer layer, so that the heating resistor supplies power to heat when the optical module is at a low temperature, and heat is conducted to the laser through the first heat transfer layer to heat the laser; the second heat transfer layer is positioned below the first heat transfer layer, a plurality of through holes are formed between the second heat transfer layer and the first heat transfer layer, and the second heat transfer layer is connected with the laser through the through holes, so that the first heat transfer layer conducts heat to the second heat transfer layer through the through holes, and the second heat transfer layer conducts heat to the laser through the through holes so as to heat the laser; the filling layer is positioned between the first heat transfer layer and the second heat transfer layer and is used for connecting the first heat transfer layer and the second heat transfer layer. This application sets up first heat transfer layer and second heat transfer layer on the circuit board, the laser instrument is located first heat transfer layer, heating resistor is located first heat transfer layer top, first heat transfer layer is connected with the second heat transfer layer through the via hole, so when the optical module is in low temperature, the heat conduction that heating resistor power supply heating produced is to first heat transfer layer, the partial heat conduction of first heat transfer layer is to the laser instrument, partial heat is to the second heat transfer layer through the via hole conduction, the second heat transfer layer is again with heat conduction to the laser instrument, the heat of heating resistor is to the laser instrument through thermal radiation, heat conduction's mode conduction, heating resistor leads the heat of laser instrument can be increased, improve heat transfer efficiency, thereby can avoid the harmful effects that low temperature environment led to the fact the laser instrument performance.

Drawings

In order to more clearly illustrate the technical solutions of the present disclosure, the drawings that need 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 may be obtained according to these drawings to those of ordinary skill in the art. Furthermore, the drawings in the following description may be regarded as schematic diagrams, not limiting the actual size of the products, the actual flow of the methods, the actual timing of the signals, etc. according to 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 module according to some embodiments;

fig. 3 is a schematic diagram of an optical module according to some embodiments;

FIG. 4 is a partially exploded schematic illustration of an optical module according to some embodiments;

fig. 5 is a schematic structural diagram of a circuit board in an optical module according to an embodiment of the present application;

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

FIG. 7 is an enlarged schematic view of FIG. 6 at A;

FIG. 8 is a schematic diagram of the analysis of FIG. 6A;

fig. 9 is a partial cross-sectional view of a circuit board in an optical module according to an embodiment of the present disclosure;

fig. 10 is a schematic diagram of a partial structure of a circuit board in an optical module according to an embodiment of the present application;

fig. 11 is a schematic diagram of a partial structure of a circuit board in an optical module according to an embodiment of the present application;

fig. 12 is a schematic diagram illustrating heat transfer on a circuit board in an optical module according to an embodiment of the present disclosure;

fig. 13 is a schematic diagram of heat transfer on a circuit board in an optical module according to an embodiment of the present disclosure;

fig. 14 is a schematic diagram of heat transfer on a circuit board in an optical module according to an embodiment of the present application.

Detailed Description

The following description of the embodiments of the present disclosure will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all, of the embodiments of the present disclosure. All other embodiments obtained by one of ordinary skill in the art based on the embodiments provided by the present disclosure are within the 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 an information processing device such as a computer through an information transmission device such as an optical fiber or an optical waveguide, so as to complete the transmission of the information. Since light has a passive transmission characteristic when transmitted through an optical fiber or an optical waveguide, low-cost, low-loss information transmission can be realized. Further, 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 mutual conversion between the electrical signal and the optical signal in order to establish an 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 electric signal in the technical field of optical communication. The optical module comprises an optical port and an electric port, the optical module realizes optical communication with information transmission equipment such as optical fibers or optical waveguides through the optical port, realizes electric connection with an optical network terminal (for example, optical cat) through the electric port, and the electric 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 information processing equipment such as a computer through a network cable or 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-range signal transmission, such as several kilometers (6 kilometers to 8 kilometers), on the basis of which, if a repeater is used, it is theoretically possible to achieve unlimited distance transmission. Thus, in a typical optical communication system, the distance between the remote server 1000 and the optical network terminal 100 may typically reach 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: routers, switches, computers, cell phones, tablet computers, televisions, 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 completed by an optical fiber 101 and a network cable 103; and the connection between the optical fiber 101 and the network cable 103 is made 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 such that the optical module 200 establishes a bi-directional optical signal connection with the optical fiber 101; the electrical port is configured to be accessed into the optical network terminal 100 such that the optical module 200 establishes a bi-directional electrical signal connection with the optical network terminal 100. The optical module 200 performs mutual conversion between optical signals and electrical signals, so that an information connection is established between the optical fiber 101 and the optical network terminal 100. Illustratively, the 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 the 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 mutual conversion between the optical signal and the electrical signal, it has no function of processing data, and the information is not changed during the above-mentioned photoelectric conversion process.

The optical network terminal 100 includes a substantially rectangular parallelepiped housing (housing), 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 and the optical module 200 establish a bidirectional electrical signal connection; 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. A connection is established between the optical module 200 and the network cable 103 through the optical network terminal 100. Illustratively, the optical network terminal 100 transmits an electrical signal from the optical module 200 to the network cable 103, and transmits an electrical signal from the network cable 103 to the optical module 200, so that the optical network terminal 100, as a host computer of the optical module 200, can monitor the operation of the optical module 200. The upper computer of the optical module 200 may include an optical line terminal (Optical Line Terminal, OLT) or 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 block diagram of an optical network terminal, and fig. 2 shows only the configuration of the optical network terminal 100 related to the optical module 200 in order to clearly show the 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 in 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 convex portion such as a fin that increases the heat dissipation area.

The optical module 200 is inserted into the cage 106 of the optical network terminal 100, the optical module 200 is fixed by the cage 106, and heat generated by the optical module 200 is transferred to the cage 106 and then diffused through the heat sink 107. After the optical module 200 is inserted into the cage 106, the electrical port of the optical module 200 is connected with an electrical connector inside the cage 106, so that the optical module 200 and the optical network terminal 100 propose a bi-directional electrical signal connection. In addition, the optical port of the optical module 200 is connected to the optical fiber 101, so that the optical module 200 establishes a bi-directional optical signal connection with the optical fiber 101.

Fig. 3 is a block diagram of an optical module according to some embodiments, and fig. 4 is an exploded view of an optical module according to some embodiments. As shown in fig. 3 and 4, the optical module 200 includes a housing (shell), a circuit board 300 disposed in the housing, and an optical transceiver module.

The housing includes an upper housing 201 and a lower housing 202, the upper housing 201 being covered on the lower housing 202 to form the above-mentioned housing having two openings; the outer contour of the housing generally presents a square shape.

In some embodiments of the present disclosure, the lower housing 202 includes a bottom plate and two lower side plates disposed at both sides of the bottom plate and perpendicular to the bottom plate; the upper case 201 includes a cover plate that is covered on both lower side plates of the lower case 202 to form the above-described case.

In some embodiments, the lower housing 202 includes a bottom plate and two lower side plates disposed at both sides of the bottom plate and perpendicular to the bottom plate; the upper case 201 includes a cover plate and two upper side plates disposed at two sides of the cover plate and perpendicular to the cover plate, and the two upper side plates are combined with the two lower side plates to realize that the upper case 201 is covered on the lower case 202.

The direction in which the two openings 204 and 205 are connected may be the same as the longitudinal direction of the optical module 200 or may be different from the longitudinal direction of the optical module 200. For example, opening 204 is located at the end of light module 200 (right end of fig. 3) and opening 205 is also located at the end of light module 200 (left end of fig. 3). Alternatively, the opening 204 is located at the end of the light module 200, while the opening 205 is located at the side of the light module 200. The opening 204 is an electrical port, from which the golden finger of the circuit board 300 extends and is inserted into a host computer (e.g., the optical network terminal 100); the opening 205 is an optical port configured to access the external optical fiber 101 such that the external optical fiber 101 connects to an optical transceiver component inside the optical module 200.

The assembly mode of combining the upper shell 201 and the lower shell 202 is adopted, so that devices such as the circuit board 300 and the optical transceiver component are conveniently installed in the shell, and packaging protection is formed on the devices by the upper shell 201 and the lower shell 202. In addition, when devices such as the circuit board 300 and the optical transceiver assembly are assembled, the positioning component, the heat dissipation component and the electromagnetic shielding component of the devices are convenient to deploy, and the automatic production implementation is facilitated.

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

In some embodiments, the optical module 200 further includes an unlocking member 203 located outside the housing thereof, and the unlocking member 203 is configured to achieve a fixed connection between the optical module 200 and the host computer, or to release the fixed connection between the optical module 200 and the host computer.

Illustratively, the unlocking member 203 is located on the outer walls of the two lower side plates of the lower housing 202, with a snap-in member that mates with an upper computer cage (e.g., 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 clamping component of the unlocking component 203; when the unlocking member 203 is pulled, the engaging member of the unlocking member 203 moves along with the unlocking member, so as to change the connection relationship between the engaging member and the host computer, so as to release the engagement relationship between the optical module 200 and the host computer, and thus the optical module 200 can be pulled out from the cage of the host computer.

The circuit board 300 includes circuit traces, electronic components and chips, which are connected together by the circuit traces according to a circuit design to realize functions such as power supply, electrical signal transmission, and grounding. The electronic components include, for example, capacitors, resistors, transistors, metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET). The chips include, for example, a micro control unit (Microcontroller Unit, MCU), a laser driving chip, a limiting amplifier (limiting amplifier), a clock data recovery (Clock and Data Recovery, CDR) chip, a power management chip, a digital signal processing (Digital Signal Processing, DSP) chip.

The circuit board 300 is generally a hard circuit board, and the hard circuit board can also realize a bearing function due to the relatively hard material, for example, the hard circuit board can stably bear the electronic components and chips; when the optical transceiver component is positioned on the circuit board, the hard circuit board can also provide stable bearing; the hard circuit board can also be inserted into an electrical connector in the upper computer cage.

The circuit board 300 further includes a gold finger 301 formed on an end surface thereof, the gold finger 301 being composed of a plurality of pins independent of each other. The circuit board 300 is inserted into the cage 106 and is conductively connected to the electrical connectors within the cage 106 by the gold fingers 301. The golden finger 301 may be disposed on only one surface (e.g. the front surface shown in fig. 4) of the circuit board 300, or may be disposed on the surfaces of the upper and lower sides of the circuit board 300, so as to adapt to the situation with large pin number requirements. The golden finger is configured to establish electrical connection with the upper computer to achieve power supply, grounding, I2C signal transmission, data signal transmission and the like.

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

The optical transceiver assembly comprises an optical transmitting assembly 400 and an optical receiving assembly, the optical transmitting assembly 400 generally comprises an optical device such as a laser and a lens, the laser is electrically connected with a laser driving chip on the circuit board 300, the laser driving chip is electrically connected with a data processing chip 302 on the circuit board 300, the data processing chip 302 transmits an electric signal transmitted by the golden finger 301 to the laser driving chip, the laser driving chip provides driving current for the laser, the laser generates an optical signal, and the optical signal is transmitted out through the optical fiber adapter 500 to realize light emission.

The optical receiving assembly generally includes optical devices such as a lens and a detector, the detector converts an optical signal transmitted from the outside into an electrical signal, the electrical signal is amplified by a transimpedance amplifier on the circuit board 300 and then transmitted to the data processing chip 302, and the data processing chip 302 processes the electrical signal and then transmits the processed electrical signal to the host computer via the golden finger 301 to realize optical receiving.

The working temperature of the laser in the optical module is 15-75 ℃, and the heat dissipation of the optical module is not concerned under the condition of low temperature in most cases, because the poor performance of the laser possibly caused by low temperature is ignored. An optical module can normally work in a normal temperature environment, and once the optical module is transferred to a low temperature environment (such as industrial low temperature), the optical module cannot normally work due to the performance cracking of a laser.

For example, a VCSEL (Vertical Cavity Surface Emitting Laser ) laser is developed based on gallium arsenide semiconductor materials, has the advantages of small volume, round output light spots, small threshold current, easiness in integration into a large-area array and the like, is widely applied to the field of optical communication, and is found that the VCSEL laser is seriously cracked in performance under a low-temperature environment in the continuous use process, so that the normal working and use of an optical module are seriously influenced.

In the existing optical module, a laser is generally placed on a semiconductor refrigerator through a COC substrate, the semiconductor refrigerator is placed on the surface of a circuit board 300, the negative electrode of the laser is directly welded with a bonding pad on the surface of the COC substrate, the positive electrode of the laser is connected with the COC substrate through wire bonding, and heat conduction is performed on the laser through the semiconductor refrigerator.

In the application, the bottom surface of the laser is directly placed on the surface of the circuit board 300, and the laser is bonded by glue, and the glue has higher fluidity on the metal copper, so that the copper of the circuit board 300 can be removed, and the laser is bonded on a resin medium of the circuit board 300; a pad is disposed on the top surface of the laser, and is electrically connected to the laser driving chip on the circuit board 300 through a wire bonding to receive a driving current provided by the laser driving chip, thereby driving the laser to generate a light beam.

In this way, the laser is directly adhered to the surface of the circuit board 300, so that it is inconvenient to set a heating component below the laser, and in order to heat the laser, a heating resistor is generally set on the circuit board 300, and heat generated by the heating resistor is conducted to the laser through the circuit board 300.

Because the circuit board 300 is composed of a plurality of layers of boards, the adjacent boards are bonded by resin, and the heat conduction and heat dissipation performance of the circuit board 300 are poor, so that when the laser is bonded on the circuit board 300, the heat of the heating resistor is conducted to the VCSEL laser only by medium conduction, and the effect on heating efficiency and heating capacity is far less than that of the VCSEL laser by metal copper conduction.

Based on the above-mentioned problem, this application has introduced PCB copper foil and copper via hole when bonding the laser instrument at circuit board 300 surface, and the heat that heating resistor produced is conducted to the laser instrument through PCB copper foil, copper via hole for heating resistor leads the heat of laser instrument more, and heat transfer efficiency is faster.

Fig. 5 is a schematic structural diagram of a circuit board in an optical module according to an embodiment of the present application, fig. 6 is a schematic structural diagram of a circuit board in an optical module according to an embodiment of the present application, and fig. 7 is an enlarged schematic diagram at a in fig. 6. As shown in fig. 5, 6 and 7, the optical module provided in the embodiment of the present application includes a laser driving chip 401, a laser 402 and a heating resistor 403, where the laser driving chip 401 is disposed on the upper surface of the circuit board 300, the laser 402 is also disposed on the circuit board 300, and the laser 402 is electrically connected with the laser driving chip 401 through a wire, and the laser driving chip 401 is connected with a data processing chip 302 disposed on the circuit board 300, so that the data processing chip 302 transmits an electrical signal to the laser driving chip 401 through a signal wire, the laser driving chip 401 provides a driving current to the laser 402 through the wire, the laser 402 generates an optical signal under the driving of the driving current, and the optical signal is emitted through the optical fiber adapter 500.

In some embodiments, the laser 402 may be a VCSEL laser, the light emitting direction of the VCSEL laser is perpendicular to the circuit board 300, and the light entering direction of the fiber optic adapter 500 is parallel to the circuit board 300, so that the emitted light perpendicular to the circuit board 300 can be coupled into the fiber optic adapter 500, and the light emitting assembly 400 further includes a lens assembly, which is disposed over the laser 402 and is used to change the propagation direction of the emitted light, so that the emitted light perpendicular to the circuit board 300 is reflected as the emitted light parallel to the circuit board 300, so that the reflected emitted light can be coupled into the fiber optic adapter 500.

The heating resistor 403 is disposed on the circuit board 300, and the heating resistor 403 includes a first electrode 404 and a second electrode 405, where the first electrode 404 and the second electrode 405 are electrically connected to the heating circuit on the circuit board 300, and the heating resistor 403 is disposed on the first electrode 404 and the second electrode 405, so that the heating circuit on the circuit board 300 supplies power to the heating resistor 403 through the first electrode 404 and the second electrode 405, so that the heating resistor 403 is powered and heated when the optical module is in a low-temperature environment.

In some embodiments, in order to control the heating resistor 403 to start or stop heating, the circuit board 300 may further be provided with an MCU and a temperature sensor, where the temperature sensor is configured to collect a working temperature of the laser in the optical module and transmit the working temperature of the laser to the MCU, the MCU compares the working temperature of the laser with a preset temperature, if the working temperature of the laser is lower than the preset temperature, it indicates that the optical module is in a low temperature environment, and the MCU controls the heating resistor 403 to perform power supply heating to heat the laser 402, so as to increase the working temperature of the laser; if the laser operating temperature is not lower than the preset temperature, it indicates that the optical module is in a normal operating environment, and the heating resistor 403 does not operate.

In some embodiments, a temperature sensor may be disposed in the MCU, where the temperature sensor collects the working temperature of the laser in the optical module, and stores the collected working temperature of the laser in a register of the MCU, and the MCU reads the working temperature of the laser, and controls the start and stop of the heating resistor 403 according to the working temperature of the laser.

Fig. 8 is a schematic diagram illustrating the decomposition of fig. 6 a, and fig. 9 is a partial cross-sectional view of a circuit board in an optical module according to an embodiment of the present application. As shown in fig. 8 and 9, to conduct the heat generated by the heating resistor 403 to the laser 402, the circuit board 300 includes a first heat transfer layer 410, a filling layer 411 and a second heat transfer layer 412, the first heat transfer layer 410 is located on the upper surface of the circuit board 300, the second heat transfer layer 412 is located below the first heat transfer layer 410, and the filling layer 411 is located between the first heat transfer layer 410 and the second heat transfer layer 412, and the first heat transfer layer 410 is connected to the second heat transfer layer 412 through the filling layer 411.

The first heat transfer layer 410 covers the projection area of the laser 402 and the heating resistor 403 on the circuit board 300, the laser 402 is disposed on the first heat transfer layer 410, the heating resistor 403 is located above the first heat transfer layer 410, so that the heat generated by the heating resistor 403 is conducted to the first heat transfer layer 410, and the first heat transfer layer 410 conducts the heat to the laser 402 to heat the laser 402.

In some embodiments, a gap is formed between the first heat transfer layer 410 and the laser driving chip 401, so that the first heat transfer layer 410 can be prevented from being connected to the laser driving chip 401, and heat conducted by the first heat transfer layer is prevented from being conducted to the laser driving chip 401, and the influence of temperature on the laser driving chip 401 is prevented.

In some embodiments, since the laser 402 is adhered to the circuit board 300 by using glue, and the glue has fluidity, in order to prevent the glue from flowing onto the first heat transfer layer 410 and affecting the thermal conductivity of the first heat transfer layer 410, the first heat transfer layer 410 is provided with a mounting groove 408 penetrating through the first heat transfer layer 410, the laser 402 is disposed on the filling layer 411 exposed at the mounting groove 408, and a gap exists between the laser 402 and the inner wall of the mounting groove 408. As such, when the laser 402 is attached, glue may flow to the gap between the laser 402 and the mounting groove 408, but not to the first heat transfer layer 410.

Specifically, the first heat transfer layer 410 includes a first sub heat transfer layer 406 and a second sub heat transfer layer 407, where one side of the first sub heat transfer layer 406 is close to and has a gap with the laser driving chip 401, and the other side of the first sub heat transfer layer 406 is connected to the second sub heat transfer layer 407, so that the first sub heat transfer layer 4-6 and the second sub heat transfer layer 407 form the first heat transfer layer 410 on the upper surface of the circuit board 300.

The mounting groove 408 is disposed on the first sub heat transfer layer 406, and an opening is disposed on a side of the mounting groove 408 facing the laser driving chip 401, and the opening is communicated with the mounting groove 408, so that after the laser 402 is disposed in the mounting groove 408, glue can be injected into the bottom of the laser 402 through the opening, thereby reducing the glue consumption and avoiding the glue from flowing onto the first sub heat transfer layer 406.

In some embodiments, the first sub heat transfer layer 406 is disposed along a left-right direction, the second sub heat transfer layer 407 is disposed along a front-back direction, and the second sub heat transfer layer 407 is perpendicular to the first sub heat transfer layer 406, such that the first sub heat transfer layer 406 and the second sub heat transfer layer 407 form a T-shaped heat transfer layer.

The second sub heat transfer layer 407 is located in the gap between the first electrode 404 and the second electrode 405, and the heating resistor 403 is located above the second sub heat transfer layer 407 to receive heat generated by the heating resistor 403 as much as possible. In this way, the heating resistor 403 generates heat when the first electrode 404 and the second electrode 405 are powered up, and the heat is transferred to the second sub heat transfer layer 407 by heat radiation, and the second sub heat transfer layer 407 transfers the heat to the first sub heat transfer layer 406.

In some embodiments, gaps may exist between the first electrode 404 and the second electrode 405 and the first and second sub heat transfer layers 406 and 407 to prevent the electrical signals transmitted from the circuit board 300 to the first and second electrodes 404 and 405 from being transmitted to the first and second sub heat transfer layers 406 and 407.

Because of the gap between the first sub-heat transfer layer 406 and the laser 402, the heat conducted by the first sub-heat transfer layer 406 is conducted to the laser 402 by heat radiation to heat the laser 402.

In some embodiments, the length dimension of the first sub heat transfer layer 406 in the left-right direction is greater than the length dimension of the second sub heat transfer layer 407 in the left-right direction, such that the heat transfer area of the first sub heat transfer layer 406 is greater than the heat transfer area of the second sub heat transfer layer 407, and the first sub heat transfer layer 406 surrounds the laser 402, such that the first sub heat transfer layer 406 can thermally radiate from the periphery of the laser 402 to the laser 402, resulting in faster heat transfer efficiency.

In some embodiments, since the laser 402 is disposed on the filling layer 411 exposed by the mounting groove 408, in order to increase the heat conduction rate to the laser 402, a metal via 409 is disposed on the filling layer 411 exposed by the mounting groove 408, and the metal via 409 is connected to the second heat transfer layer 412, the laser 402 is disposed on the metal via 409, so that the laser 402 is connected to the second heat transfer layer 412 through the metal via 409, and thus, the heat conducted by the second heat transfer layer 412 can be directly conducted to the bottom of the laser 402 through the metal via 409, so as to increase the heat conduction rate.

The structure of the second heat transfer layer 412 is the same as that of the first heat transfer layer 410, so that the second heat transfer layer 412 includes a third sub heat transfer layer and a fourth sub heat transfer layer, the third sub heat transfer layer is disposed opposite to the first sub heat transfer layer, and the fourth sub heat transfer layer is disposed opposite to the second sub heat transfer layer, such that the third sub heat transfer layer and the fourth sub heat transfer layer form a T-shaped heat transfer layer.

A plurality of vias 409 are disposed between the first heat transfer layer 410 and the second heat transfer layer 412, and heat from the first heat transfer layer 410 is transferred to the second heat transfer layer 412 through the vias 409. That is, a plurality of vias 409 are provided between the first sub heat transfer layer 406 and the third sub heat transfer layer, a plurality of vias 409 are provided between the second sub heat transfer layer 407 and the fourth sub heat transfer layer, after the heat generated by the heating resistor 403 is radiated to the second sub heat transfer layer 407, the second sub heat transfer layer 407 conducts part of the heat to the first sub heat transfer layer 406, and the second sub heat transfer layer 407 conducts the rest of the heat to the fourth sub heat transfer layer through the vias 409.

The first sub-heat transfer layer 406 conducts part of the conducted heat to the laser 402 by heat radiation, the first sub-heat transfer layer 406 conducts the remaining part of the heat to the third sub-heat transfer layer through the via 409, and the fourth sub-heat transfer layer conducts the heat to the third sub-heat transfer layer, which directly conducts the heat to the bottom of the laser 402 through the via 409.

In some embodiments, the first heat transfer layer 410 and the second heat transfer layer 412 are both heat transfer copper layers, the via 409 is a copper via, and the filling layer 411 is a resin medium layer, so that the first heat transfer layer 410, the second heat transfer layer 412 and the filling layer 411 can conduct heat to the laser 402, so that the heat transfer efficiency to the laser 402 is faster.

Fig. 10 is a schematic diagram of a partial structure of a circuit board in an optical module according to an embodiment of the present application, and fig. 11 is a schematic diagram of a partial structure of a circuit board in an optical module according to an embodiment of the present application. As shown in fig. 10 and 11, on the upper surface of the circuit board 300, the first sub heat transfer layer 406 and the second sub heat transfer layer 407 form a T-shaped first heat transfer layer 410, the first sub heat transfer layer 406 is provided with a mounting groove 408, and the filling layer 411 exposed at the mounting groove 408 is provided with a metal via 409.

In the inner layer of the circuit board 300, the third sub heat transfer layer and the fourth sub heat transfer layer form a T-shaped second heat transfer layer 412, a plurality of via holes 409 are disposed between the first heat transfer layer 410 and the second heat transfer layer 412, and the first heat transfer layer 410 conducts heat with the second heat transfer layer 412 through the via holes 409.

In some embodiments, a metal layer is further disposed on the upper surface of the circuit board 300, where a laser driving chip 401, a transimpedance amplifier, an MCU, and other optoelectronic devices are disposed on the metal layer, but a gap exists between the metal layer and the first heat transfer layer 410, so as to prevent heat conducted by the first heat transfer layer 410 from diffusing to the metal layer, so that heat is conducted on the first heat transfer layer 410 as much as possible, and heat is prevented from heating other optoelectronic devices on the metal layer, and performance of other optoelectronic devices is affected.

Fig. 12 is a schematic diagram of heat transfer on a circuit board in an optical module provided in an embodiment of the present application, fig. 13 is a schematic diagram of heat transfer on a circuit board in an optical module provided in an embodiment of the present application, and fig. 14 is a schematic diagram of heat transfer on a circuit board in an optical module provided in an embodiment of the present application. As shown in fig. 12, 13 and 14, since the second sub heat transfer layer 407 extends to the bottom of the heating resistor 403, the heat generated by the heating resistor 403 is radiated to the second sub heat transfer layer 407, then the second sub heat transfer layer 407 transfers the heat to the first sub heat transfer layer 406, and the first sub heat transfer layer 406 radiates the heat to the laser 402 by using a heat radiation manner, so that the first heat transfer layer 410 radiates the heat to the laser 402.

Since the second heat transfer layer 412 is connected to the first heat transfer layer 410 through the via 409, the heat of the second sub heat transfer layer 407 is transferred to the fourth sub heat transfer layer of the second heat transfer layer 412 through the via 409, the heat of the first sub heat transfer layer 406 is transferred to the third sub heat transfer layer of the second heat transfer layer 412 through the via 409, and the fourth sub heat transfer layer transfers the heat to the third sub heat transfer layer, and the third sub heat transfer layer transfers the heat directly to the bottom of the laser 402 through the via 409, so that the second heat transfer layer 412 transfers the heat to the laser 402.

The optical module comprises a circuit board, a laser driving chip, a laser and a heating resistor, wherein the circuit board comprises a first heat transfer layer, a second heat transfer layer and a filling layer, the first heat transfer layer is arranged on the upper surface of the circuit board, the laser driving chip is arranged on the upper surface of the circuit board, a gap is reserved between the first heat transfer layer and the laser driving chip, and the first heat transfer layer is prevented from being connected with the laser driving chip, so that heat is prevented from being conducted to the laser driving chip; the first heat transfer layer covers a projection area of the laser and the heating resistor on the circuit board, the laser is arranged on the first heat transfer layer, and the laser is electrically connected with the laser driving chip through wire bonding so as to generate an optical signal according to driving current provided by the laser driving chip; the first heat transfer layer is provided with a penetrating mounting groove, a metal via hole is arranged between the filling layer exposed out of the mounting groove and the second heat transfer layer, and the laser is arranged on the metal via hole of the filling layer, so that the laser is connected with the second heat transfer layer through the via hole; gaps exist between the laser and the inner wall of the mounting groove so as to prevent glue water adhering to the laser from flowing onto the first heat transfer layer; the heating resistor is positioned above the first heat transfer layer, so that the heating resistor supplies power to heat when the optical module is at a low temperature, and heat is conducted to the laser through the first heat transfer layer to heat the laser; the second heat transfer layer is positioned below the first heat transfer layer, a plurality of through holes are formed between the second heat transfer layer and the first heat transfer layer, and the second heat transfer layer is connected with the laser through the through holes, so that the first heat transfer layer conducts heat to the second heat transfer layer through the through holes, and the second heat transfer layer conducts heat to the laser through the through holes so as to heat the laser; the filling layer is positioned between the first heat transfer layer and the second heat transfer layer and is used for connecting the first heat transfer layer and the second heat transfer layer. This application sets up first heat transfer layer and second heat transfer layer on the circuit board, the laser instrument is located first heat transfer layer, heating resistor is located first heat transfer layer top, first heat transfer layer is connected with the second heat transfer layer through the via hole, so when the laser instrument of optical module is in low temperature, the heat conduction that heating resistor power supply heating produced is to first heat transfer layer, first heat transfer layer adopts the heat radiation mode to radiate the heat to the laser instrument, simultaneously first heat transfer layer passes through the via hole conduction to the second heat transfer layer, the second heat transfer layer passes through the via hole and directly conducts the heat to the laser instrument, the heat of so heating resistor is conducted to the laser instrument through thermal radiation, the mode of thermal conduction, heating resistor conduction to the heat of laser instrument has been increased, heat transfer efficiency has been improved, the operating temperature of laser instrument has been kept, thereby the harmful effects that low temperature environment caused the laser instrument performance have been avoided.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and are not limiting thereof; 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 scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the corresponding technical solutions.

Claims

1. An optical module, comprising:

a circuit board;

the laser driving chip is arranged on the circuit board;

wherein, the circuit board includes:

2. The optical module of claim 1, wherein the first heat transfer layer covers the laser and the projection area of the heating resistor on the circuit board, the first heat transfer layer comprises a first sub heat transfer layer and a second sub heat transfer layer, one side of the first sub heat transfer layer is close to and has a gap with the laser driving chip, and the other side of the first sub heat transfer layer is connected with the second sub heat transfer layer;

the heating resistor is located above the second sub heat transfer layer.

3. The optical module of claim 2, wherein a length dimension of the first sub heat transfer layer in a left-right direction is greater than a length dimension of the second sub heat transfer layer in the left-right direction, and wherein a heat transfer area of the first sub heat transfer layer is greater than a heat transfer area of the second sub heat transfer layer.

4. The optical module according to claim 2, wherein the heating resistor comprises a first electrode and a second electrode, the first electrode and the second electrode are electrically connected with the circuit board, the heating resistor is positioned on the first electrode and the second electrode, and the heating resistor is powered and heated by the first electrode and the second electrode;

and a gap is formed between the first electrode and the second electrode, the second sub heat transfer layer is positioned in the gap, and gaps are formed among the first electrode, the second electrode, the first sub heat transfer layer and the second sub heat transfer layer.

5. The optical module according to claim 2, wherein a through mounting groove is formed in the first sub heat transfer layer, and an opening is formed in a side of the mounting groove facing the laser driving chip;

the laser is positioned on the filling layer exposed at the mounting groove, and a gap exists between the laser and the inner wall of the mounting groove.

6. The optical module of claim 5, wherein a metal via is disposed on the filling layer exposed at the mounting groove, the laser is disposed on the metal via, and the metal via is connected to the second heat transfer layer.

7. The optical module of claim 1, wherein the first heat transfer layer and the second heat transfer layer are each T-shaped.

8. The optical module of claim 1, wherein the first heat transfer layer and the second heat transfer layer are both heat transfer copper layers, and the via is a copper via.

9. The optical module of claim 1, wherein the filler layer is a resin dielectric layer.

10. The light module of claim 1 further comprising a temperature sensor disposed on the circuit board for collecting a laser operating temperature within the light module.