An optical module

Abstract

This application provides an optical module, including a circuit board and a laser driver chip, a laser, and a heating resistor disposed on the circuit board. The laser is electrically connected to the laser driver chip via wire bonding, and the heating resistor is used to heat the laser at low temperatures. The circuit board includes a first heat transfer layer, a second heat transfer layer, and a filler layer between the first and second heat transfer layers. The first heat transfer layer is located on the upper surface of the circuit board and has a gap with the laser driver chip. The laser is disposed on the first heat transfer layer, and the heat from the heating resistor is conducted to the laser through the first heat transfer layer. The second heat transfer layer is located below the first heat transfer layer and has multiple vias between it and the first heat transfer layer, connecting to the laser through the vias. This application provides first and second heat transfer layers connected by vias on the circuit board. The laser is located on the first heat transfer layer, and the heat from the heating resistor is conducted to the laser through the first and second heat transfer layers, resulting in more heat being conducted from the heating resistor to the laser and faster heat transfer efficiency.

Description

Technical Field

[0001] This application relates to the field of optical communication technology, and in particular to an optical module. Background Technology

[0002] With the development of new business and application models such as cloud computing, mobile internet, and video, the advancement of optical communication technology has become increasingly important. In optical communication technology, optical modules are the tools for converting between photoelectric signals and signals, and are one of the key components in optical communication equipment. Furthermore, with the evolving needs of optical communication technology, the transmission rate of optical modules is constantly increasing.

[0003] Optical modules typically consist of a circuit board and a laser mounted on the circuit board. The laser operates at temperatures ranging from 15°C to 75°C, and heat dissipation is often not a primary concern in low-temperature environments. However, during use, it has been observed that when optical modules are exposed to low-temperature environments, such as industrial-grade low-temperature environments (-40°C), the laser's performance often deteriorates due to the cold environment, resulting in phenomena such as a drop in optical power, spectral shift, and reduced laser bandwidth, ultimately causing the optical module to malfunction. Summary of the Invention

[0004] This application provides an optical module that heats the laser in the optical module under low-temperature conditions to maintain the laser's operating temperature and thus avoid adverse effects of low-temperature conditions on the laser's performance.

[0005] This application provides a circuit board, including:

[0006] Circuit board;

[0007] A laser driver chip is mounted on the circuit board;

[0008] The laser is attached to the circuit board, and its top surface is electrically connected to the laser driver chip via wire bonding.

[0009] A heating resistor, electrically connected to the circuit board, is used to heat the laser at low temperatures;

[0010] The circuit board includes:

[0011] A first heat transfer layer is located on the upper surface of the circuit board and has a gap with the laser driving chip; the laser is disposed on the first heat transfer layer and the heating resistor is located above the first heat transfer layer; it is used to conduct the heat generated by the heating resistor to the laser.

[0012] The second heat transfer layer is located below the first heat transfer layer and has multiple through holes between it and the first heat transfer layer. It is connected to the laser through the through holes and is used to conduct heat conducted through the through holes to the laser.

[0013] A filler layer, located between the first heat transfer layer and the second heat transfer layer, is used to connect the first heat transfer layer and the second heat transfer layer.

[0014] As can be seen from the above embodiments, the optical module provided in this application includes a circuit board, a laser driver chip, a laser, and a heating resistor. The circuit board includes a first heat transfer layer, a second heat transfer layer, and a filler layer. The first heat transfer layer is located on the upper surface of the circuit board, and the laser driver chip is disposed on the upper surface of the circuit board. There is a gap between the first heat transfer layer and the laser driver chip to prevent the first heat transfer layer from connecting with the laser driver chip, thereby preventing heat conduction to the laser driver chip. The laser is attached to the first heat transfer layer, and the pads on the top surface of the laser are electrically connected to the laser driver chip via wire bonding to drive the laser according to the driving current provided by the laser driver chip. The optical module generates an optical signal. A heating resistor is located above the first heat transfer layer. When the optical module is at a low temperature, the heating resistor supplies power for heating. The heat is conducted to the laser through the first heat transfer layer to heat the laser. A second heat transfer layer is located below the first heat transfer layer. Multiple vias are provided between the second and first heat transfer layers. The second heat transfer layer is connected to the laser through the vias. Thus, the first heat transfer layer conducts heat to the second heat transfer layer through the vias, and the second heat transfer layer then conducts heat to the laser through the vias to heat the laser. A filler layer is located between the first and second heat transfer layers to connect the first and second heat transfer layers. This application sets up a first heat transfer layer and a second heat transfer layer on a circuit board. The laser is located on the first heat transfer layer, and the heating resistor is located above the first heat transfer layer. The first heat transfer layer is connected to the second heat transfer layer through a via. In this way, when the optical module is at a low temperature, the heat generated by the heating resistor is conducted to the first heat transfer layer. Part of the heat from the first heat transfer layer is conducted to the laser, and part of the heat is conducted to the second heat transfer layer through the via. The second heat transfer layer then conducts the heat to the laser. In this way, the heat from the heating resistor is conducted to the laser through thermal radiation and thermal conduction, which can increase the heat transfer efficiency of the heating resistor to the laser and thus avoid the adverse effects of low temperature environment on laser performance. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in this disclosure, the accompanying drawings used in some embodiments of this disclosure will be briefly described below. Obviously, the drawings described below are only drawings of some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams and are not intended to limit the actual size of the product, the actual flow of the method, the actual timing of the signals, etc. involved in the embodiments of this disclosure.

[0016] Figure 1 This is a connection diagram of an optical communication system according to some embodiments;

[0017] Figure 2 This is a structural diagram of an optical module according to some embodiments;

[0018] Figure 3 This is a schematic diagram of the structure of an optical module according to some embodiments;

[0019] Figure 4 This is a partially exploded view of an optical module according to some embodiments;

[0020] Figure 5 A schematic diagram of the circuit board structure in an optical module provided in this application embodiment. Figure 1 ;

[0021] Figure 6 A schematic diagram of the circuit board structure in an optical module provided in this application embodiment. Figure 2 ;

[0022] Figure 7 for Figure 6 Enlarged view of point A in the middle;

[0023] Figure 8 for Figure 6 Schematic diagram of the decomposition at point A in the middle;

[0024] Figure 9 A partial cross-sectional view of a circuit board in an optical module provided in an embodiment of this application;

[0025] Figure 10 A partial structural diagram of a circuit board in an optical module provided in this application embodiment. Figure 1 ;

[0026] Figure 11 A partial structural diagram of a circuit board in an optical module provided in this application embodiment. Figure 2 ;

[0027] Figure 12 A schematic diagram of heat transfer on a circuit board in an optical module provided in this application embodiment. Figure 1 ;

[0028] Figure 13 A schematic diagram of heat transfer on a circuit board in an optical module provided in this application embodiment. Figure 2 ;

[0029] Figure 14 A schematic diagram of heat transfer on a circuit board in an optical module provided in this application embodiment. Figure 3 . Detailed Implementation

[0030] The technical solutions in some embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments provided in this disclosure are within the scope of protection of this disclosure.

[0031] In optical communication systems, optical signals carry the information to be transmitted and are transmitted through information transmission equipment such as optical fibers or waveguides to information processing equipment such as computers to complete the information transmission. Because light has passive transmission characteristics when transmitted through optical fibers or waveguides, low-cost, low-loss information transmission can be achieved. However, the signals transmitted by information transmission equipment such as optical fibers or waveguides are optical signals, while the signals that information processing equipment such as computers can recognize and process are electrical signals. Therefore, in order to establish an information connection between information transmission equipment such as optical fibers or waveguides and information processing equipment such as computers, it is necessary to achieve mutual conversion between electrical and optical signals.

[0032] In the field of optical communication technology, optical modules realize the mutual conversion function between optical signals and electrical signals. An optical module includes an optical port and an electrical port. The optical port enables optical communication with information transmission devices such as optical fibers or optical waveguides, while the electrical port enables electrical connection with optical network terminals (e.g., optical modems). The electrical connection is mainly used for power supply, I2C signal transmission, data transmission, and grounding. The optical network terminal transmits electrical signals to information processing devices such as computers via network cables or Wi-Fi.

[0033] Figure 1 This is a diagram showing the connection relationships within an optical communication system. (Example:) Figure 1 As shown, 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.

[0034] One end of optical fiber 101 is connected to the remote server 1000, and the other end is connected to the optical network terminal 100 via optical module 200. Optical fiber itself can support long-distance signal transmission, such as signal transmission over several kilometers (6 to 8 kilometers). Theoretically, unlimited distance transmission can be achieved by using repeaters. Therefore, in typical optical communication systems, the distance between the remote server 1000 and the optical network terminal 100 can typically reach several kilometers, tens of kilometers, or hundreds of kilometers.

[0035] 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 device 2000 can be any one or more of the following devices: router, switch, computer, mobile phone, tablet computer, television, etc.

[0036] 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 device 2000 and the optical network terminal 100. The connection between the local information processing device 2000 and the remote server 1000 is completed by optical fiber 101 and network cable 103; while the connection between optical fiber 101 and network cable 103 is completed by optical module 200 and optical network terminal 100.

[0037] The optical module 200 includes an optical port and an electrical port. The optical port is configured to connect to the optical fiber 101, thereby establishing a bidirectional optical signal connection between the optical module 200 and the optical fiber 101. The electrical port is configured to connect to the optical network terminal 100, thereby establishing a bidirectional electrical signal connection between the optical module 200 and the optical network terminal 100. The optical module 200 performs mutual conversion between optical and electrical signals, thereby establishing an information connection between the optical fiber 101 and the optical network terminal 100. For example, 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 then input to the optical fiber 101. Since the optical module 200 is a tool for mutual conversion between optical and electrical signals and does not have the function of data processing, the information does not change during the above photoelectric conversion process.

[0038] The optical network terminal 100 includes a generally cuboid housing, and an optical module interface 102 and a network cable interface 104 disposed on the housing. The optical module interface 102 is configured to connect to an optical module 200, thereby establishing a bidirectional electrical signal connection between the optical network terminal 100 and the optical module 200; the network cable interface 104 is configured to connect to a network cable 103, thereby establishing a bidirectional electrical signal connection between the optical network terminal 100 and the network cable 103. The optical module 200 and the network cable 103 are connected through the optical network terminal 100. For example, the optical network terminal 100 transmits electrical signals from the optical module 200 to the network cable 103, and vice versa, thus the optical network terminal 100 acts as a host computer for the optical module 200, monitoring its operation. Besides the optical network terminal 100, the host computer for the optical module 200 may also include an optical line terminal (OLT), etc.

[0039] The remote server 1000 establishes a bidirectional signal transmission channel with the local information processing equipment 2000 through optical fiber 101, optical module 200, optical network terminal 100 and network cable 103.

[0040] Figure 2 This is a structural diagram of an optical network terminal. To clearly show the connection relationship between the optical module 200 and the optical network terminal 100... Figure 2 Only the structure of the optical network terminal 100 related to the optical module 200 is shown. For example... Figure 2 As shown, the optical network terminal 100 also includes a circuit board 105 disposed within a housing, a cage 106 disposed on the 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 connect to the electrical port of the optical module 200; the heat sink 107 has protrusions such as fins to increase the heat dissipation area.

[0041] The optical module 200 is inserted into the cage 106 of the optical network terminal 100, where it is secured. Heat generated by the optical module 200 is conducted to the cage 106 and then dissipated through the heat sink 107. After insertion into the cage 106, the optical module 200's electrical port connects to an electrical connector inside the cage 106, establishing a bidirectional electrical signal connection between the optical module 200 and the optical network terminal 100. Furthermore, the optical port of the optical module 200 connects to the optical fiber 101, establishing a bidirectional optical signal connection between the optical module 200 and the optical fiber 101.

[0042] Figure 3 This is a structural diagram of an optical module according to some embodiments. Figure 4 This is an exploded view of an optical module according to some embodiments. Figure 3 , Figure 4 As shown, the optical module 200 includes a shell, a circuit board 300 disposed inside the shell, and an optical transceiver assembly.

[0043] The housing includes an upper housing 201 and a lower housing 202, with the upper housing 201 covering the lower housing 202 to form the aforementioned housing with two openings; the outer contour of the housing is generally square.

[0044] In some embodiments of this disclosure, the lower housing 202 includes a base plate and two lower side plates located on both sides of the base plate and disposed perpendicular to the base plate; the upper housing 201 includes a cover plate, which covers the two lower side plates of the lower housing 202 to form the aforementioned housing.

[0045] In some embodiments, the lower housing 202 includes a bottom plate and two lower side plates located on both sides of the bottom plate and arranged perpendicularly to the bottom plate; the upper housing 201 includes a cover plate and two upper side plates located on both sides of the cover plate and arranged perpendicularly to the cover plate, wherein the two upper side plates are combined with the two lower side plates to realize that the upper housing 201 covers the lower housing 202.

[0046] The direction of the line connecting the two openings 204 and 205 can be consistent with or inconsistent with the length direction of the optical module 200. For example, opening 204 is located at the end of the optical module 200. Figure 3The opening 205 is also located at the end of the optical module 200 (right end). Figure 3 (Left end). Alternatively, opening 204 is located at the end of optical module 200, while opening 205 is located on the side of optical module 200. Opening 204 is an electrical port, from which the gold fingers of circuit board 300 extend and are inserted into a host computer (e.g., optical network terminal 100); opening 205 is an optical port, configured to connect to external optical fiber 101 so that external optical fiber 101 can connect to the optical transceiver assembly inside optical module 200.

[0047] The assembly method using an upper housing 201 and a lower housing 202 facilitates the installation of components such as the circuit board 300 and optical transceiver assemblies into the housing, with the upper housing 201 and lower housing 202 providing encapsulation and protection for these components. Furthermore, the assembly of the circuit board 300 and optical transceiver assemblies facilitates the deployment of positioning components, heat dissipation components, and electromagnetic shielding components, which is beneficial for automated production.

[0048] In some embodiments, the upper housing 201 and the lower housing 202 are generally made of metal materials, which facilitates electromagnetic shielding and heat dissipation.

[0049] In some embodiments, the optical module 200 further includes an unlocking component 203 located outside its housing, the unlocking component 203 being configured to establish 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.

[0050] For example, the unlocking component 203 is located on the outer wall of the two lower side plates of the lower housing 202, and has a locking component that matches the host computer cage (e.g., the cage 106 of the optical network terminal 100). When the optical module 200 is inserted into the host computer cage, the locking component of the unlocking component 203 fixes the optical module 200 in the host computer cage; when the unlocking component 203 is pulled, the locking component of the unlocking component 203 moves accordingly, thereby changing the connection relationship between the locking component and the host computer, so as to release the locking relationship between the optical module 200 and the host computer, thereby allowing the optical module 200 to be pulled out of the host computer cage.

[0051] Circuit board 300 includes circuit traces, electronic components, and chips. The circuit traces connect the electronic components and chips according to the circuit design to achieve functions such as power supply, electrical signal transmission, and grounding. Electronic components include, for example, capacitors, resistors, transistors, and metal-oxide-semiconductor field-effect transistors (MOSFETs). Chips include, for example, microcontroller units (MCUs), laser driver chips, limiting amplifiers, clock and data recovery (CDR) chips, power management chips, and digital signal processing (DSP) chips.

[0052] Circuit board 300 is generally a rigid circuit board. Due to its relatively rigid material, the rigid circuit board can also perform a load-bearing function. For example, the rigid circuit board can stably support the aforementioned electronic components and chips. When the optical transceiver assembly is located on the circuit board, the rigid circuit board can also provide stable support. The rigid circuit board can also be inserted into the electrical connector in the host computer cage.

[0053] The circuit board 300 also includes gold fingers 301 formed on its end surface, the gold fingers 301 consisting of a plurality of independent pins. The circuit board 300 is inserted into the cage 106 and is electrically connected to an electrical connector within the cage 106 by the gold fingers 301. The gold fingers 301 may be provided only on one side of the surface of the circuit board 300 (e.g., Figure 4 (As shown on the front side), it can also be placed on the upper and lower surfaces of the circuit board 300 to accommodate applications with a large number of pins. The gold fingers are configured to establish an electrical connection with the host computer to achieve power supply, grounding, I2C signal transmission, data signal transmission, etc.

[0054] Of course, flexible circuit boards are also used in some optical modules. Flexible circuit boards are generally used in conjunction with rigid circuit boards as a supplement to rigid circuit boards. For example, flexible circuit boards can be used to connect rigid circuit boards to optical transceiver components.

[0055] The optical transceiver assembly includes an optical emitting assembly 400 and an optical receiving assembly. The optical emitting assembly 400 typically includes optical devices such as a laser and a lens. The laser is electrically connected to a laser driver chip on the circuit board 300. The laser driver chip is electrically connected to a data processing chip 302 on the circuit board 300. The data processing chip 302 transmits the electrical signal transmitted by the gold finger 301 to the laser driver chip. The laser driver chip provides a driving current to the laser, causing the laser to generate an optical signal. The optical signal is transmitted through the fiber optic adapter 500 to realize the emission of light.

[0056] The optical receiving component typically includes optical devices such as lenses and detectors. The detector converts the externally transmitted optical signal into an electrical signal. The electrical signal is amplified by the transimpedance amplifier on the circuit board 300 and then transmitted to the data processing chip 302. The data processing chip 302 processes the electrical signal and then transmits it to the host computer via the gold finger 301 to realize the reception of light.

[0057] The operating temperature of the laser in an optical module ranges from 15℃ to 75℃. In most cases, heat dissipation in low-temperature environments is not a primary concern, which leads to the overlooking of potential laser performance degradation caused by low temperatures. An optical module that functions normally at room temperature may malfunction when transferred to a low-temperature environment (such as industrial-grade cryogenics) due to laser performance degradation.

[0058] VCSEL (Vertical Cavity Surface Emitting Laser) lasers are developed based on gallium arsenide semiconductor materials. They have advantages such as small size, circular output spot, low threshold current, and easy integration into large-area arrays. They are widely used in the field of optical communication. However, during continuous use, it has been found that VCSEL lasers generally experience severe performance degradation at low temperatures, which seriously affects the normal operation of optical modules.

[0059] In existing optical modules, the laser is generally placed on a semiconductor cooler via a COC substrate. The semiconductor cooler is placed on the surface of the circuit board 300. The negative electrode of the laser is directly soldered to the pads on the surface of the COC substrate, and the positive electrode of the laser is connected to the COC substrate via wire bonding. Heat is conducted to the laser through the semiconductor cooler.

[0060] In this application, the bottom surface of the laser is placed directly on the surface of the circuit board 300, and the laser is bonded with adhesive. Since the adhesive has a large fluidity on metallic copper, the circuit board 300 will remove copper to bond the laser to the resin medium of the circuit board 300. A pad is provided on the top surface of the laser. The pad is electrically connected to the laser driver chip on the circuit board 300 through wire bonding to receive the driving current provided by the laser driver chip, thereby driving the laser to generate a beam.

[0061] Thus, the laser is directly bonded to the surface of the circuit board 300, making it inconvenient to set up a heating component below the laser. To heat the laser, a heating resistor is usually set on the circuit board 300, and the heat generated by the heating resistor is conducted to the laser through the circuit board 300.

[0062] Since the circuit board 300 is composed of multiple layers and adjacent boards are bonded together with resin, the heat conduction and heat dissipation performance of the circuit board 300 is not good. Therefore, when the laser is bonded to the circuit board 300, the heat from the heating resistor is conducted to the VCSEL laser only through the medium. This is inevitably far less efficient and effective than the heat generated by conduction through metal copper.

[0063] Based on the above problems, this application introduces PCB copper foil and copper vias when bonding the laser to the surface of the circuit board 300. The heat generated by the heating resistor is conducted to the laser through the PCB copper foil and copper vias, so that the heating resistor conducts more heat to the laser and the heat transfer efficiency is faster.

[0064] Figure 5 A schematic diagram of the circuit board structure in the optical module provided in this application embodiment. Figure 1 , Figure 6 A schematic diagram of the circuit board structure in the optical module provided in this application embodiment. Figure 2 , Figure 7 for Figure 6 Enlarged diagram of point A in the middle. (See diagram below.) Figure 5 , Figure 6 , Figure 7 As shown, the optical module provided in this embodiment includes a laser driver chip 401, a laser 402, and a heating resistor 403. The laser driver chip 401 is disposed on the upper surface of the circuit board 300, and the laser 402 is also disposed on the circuit board 300. The laser 402 is electrically connected to the laser driver chip 401 through wire bonding. The laser driver chip 401 is connected to the data processing chip 302 disposed on the circuit board 300. Thus, the data processing chip 302 transmits electrical signals to the laser driver chip 401 through signal lines. The laser driver chip 401 provides driving current to the laser 402 through wire bonding. The laser 402 generates optical signals under the drive of the driving current, and the optical signals are emitted through the optical fiber adapter 500.

[0065] In some embodiments, the laser 402 may be a VCSEL laser, the output direction of which is perpendicular to the circuit board 300, and the input direction of the fiber optic adapter 500 is parallel to the circuit board 300. In order to enable the emitted light perpendicular to the circuit board 300 to be coupled into the fiber optic adapter 500, the light emitting assembly 400 further includes a lens assembly, which is disposed above the laser 402. The lens assembly is used to change the propagation direction of the emitted light, so that the emitted light perpendicular to the circuit board 300 is reflected into emitted light parallel to the circuit board 300, so that the reflected emitted light can be coupled into the fiber optic adapter 500.

[0066] 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. The first electrode 404 and the second electrode 405 are both electrically connected to the heating circuit on the circuit board 300, and the heating resistor 403 is located on the first electrode 404 and the second electrode 405. Thus, 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 supplies power for heating when the optical module is in a low temperature environment.

[0067] In some embodiments, in order to control the heating resistor 403 to turn on or off, an MCU and a temperature sensor may also be provided on the circuit board 300. The temperature sensor is used to collect the operating temperature of the laser in the optical module and transmit the laser operating temperature to the MCU. The MCU compares the laser operating temperature with a preset temperature. If the laser operating temperature is lower than the preset temperature, it indicates that the optical module is in a low-temperature environment. The MCU controls the heating resistor 403 to supply power for heating to heat the laser 402 and increase the laser operating temperature. 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 work.

[0068] In some embodiments, the temperature sensor may also be located within the MCU. The temperature sensor collects the operating temperature of the laser in the optical module and stores the collected operating temperature of the laser in the register of the MCU. The MCU reads the operating temperature of the laser and controls the start and stop of the heating resistor 403 according to the operating temperature of the laser.

[0069] Figure 8 for Figure 6 Schematic diagram of the decomposition at point A in the middle. Figure 9 This is a partial cross-sectional view of the circuit board in the optical module provided in an embodiment of this application. Figure 8 , Figure 9 As shown, in order 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 filler 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 filler layer 411 is located between the first heat transfer layer 410 and the second heat transfer layer 412. The first heat transfer layer 410 is connected to the second heat transfer layer 412 through the filler layer 411.

[0070] 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, and the heating resistor 403 is located above the first heat transfer layer 410. Thus, 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.

[0071] In some embodiments, there is a gap between the first heat transfer layer 410 and the laser driver chip 401, which can prevent the first heat transfer layer 410 from being connected to the laser driver chip 401. This avoids the heat conducted by the first heat transfer layer from being conducted to the laser driver chip 401, thus preventing the temperature from affecting the laser driver chip 401.

[0072] In some embodiments, since the laser 402 is attached to the circuit board 300 using adhesive, and the adhesive is fluid, to prevent the adhesive from flowing onto the first heat transfer layer 410 and affecting its thermal conductivity, a mounting groove 408 is provided on the first heat transfer layer 410, penetrating the first heat transfer layer 410. The laser 402 is disposed on the filler 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. Thus, when attaching the laser 402, the adhesive may flow into the gap between the laser 402 and the mounting groove 408, but will not flow into the first heat transfer layer 410.

[0073] Specifically, the first heat transfer layer 410 includes a first sub-heat transfer layer 406 and a second sub-heat transfer layer 407. 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. Thus, the first sub-heat transfer layer 406 and the second sub-heat transfer layer 407 form the first heat transfer layer 410 on the upper surface of the circuit board 300.

[0074] The mounting slot 408 is disposed on the first sub-heat transfer layer 406, and the mounting slot 408 has an opening on the side facing the laser driver chip 401. The opening is connected to the mounting slot 408. After the laser 402 is placed in the mounting slot 408, glue can be injected into the bottom of the laser 402 through the opening, which can reduce the amount of glue used and prevent the glue from flowing onto the first sub-heat transfer layer 406.

[0075] In some embodiments, the first sub-heat transfer layer 406 is disposed along the left-right direction, the second sub-heat transfer layer 407 is disposed along the front-back direction, and the second sub-heat transfer layer 407 is perpendicular to the first sub-heat transfer layer 406, so that the first sub-heat transfer layer 406 and the second sub-heat transfer layer 407 form a T-shaped heat transfer layer.

[0076] The second sub-heat transfer layer 407 is located within 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 maximize the absorption of heat generated by the heating resistor 403. Thus, when the first electrode 404 and the second electrode 405 are energized, the heating resistor 403 generates heat, which is conducted to the second sub-heat transfer layer 407 via thermal radiation. The second sub-heat transfer layer 407 then conducts the heat to the first sub-heat transfer layer 406.

[0077] In some embodiments, gaps may exist between the first electrode 404, the second electrode 405 and the first sub-heat transfer layer 406 and the second sub-heat transfer layer 407 to prevent electrical signals transmitted from the circuit board 300 to the first electrode 404 and the second electrode 405 from being transmitted to the first sub-heat transfer layer 406 and the second sub-heat transfer layer 407.

[0078] Since there is a 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 thermal radiation to heat the laser 402.

[0079] In some embodiments, the length of the first sub-heat transfer layer 406 in the left-right direction is greater than the length of the second sub-heat transfer layer 407 in the left-right direction, so 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. In this way, the first sub-heat transfer layer 406 can radiate heat from the surroundings of the laser 402 to the laser 402, so that the heat transfer efficiency is faster.

[0080] In some embodiments, since the laser 402 is disposed on the exposed filling layer 411 of the mounting groove 408, in order to improve the heat conduction rate of the laser 402, a metal via 409 is provided on the exposed filling layer 411 of 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. In this way, 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 to improve the heat conduction rate.

[0081] The structure of the second heat transfer layer 412 is the same as that of the first heat transfer layer 410. Therefore, 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 arranged opposite to the first sub-heat transfer layer, and the fourth sub-heat transfer layer is arranged opposite to the second sub-heat transfer layer, so that the third sub-heat transfer layer and the fourth sub-heat transfer layer form a T-shaped heat transfer layer.

[0082] Multiple vias 409 are provided between the first heat transfer layer 410 and the second heat transfer layer 412, and the heat from the first heat transfer layer 410 is conducted to the second heat transfer layer 412 through the vias 409. That is, multiple vias 409 are provided between the first sub-heat transfer layer 406 and the third sub-heat transfer layer, and multiple 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 remaining heat to the fourth sub-heat transfer layer through the vias 409.

[0083] The first sub-heat transfer layer 406 conducts part of the heat to the laser 402 through thermal radiation. The first sub-heat transfer layer 406 conducts the remaining heat to the third sub-heat transfer layer through the via 409. At the same time, the fourth sub-heat transfer layer conducts heat to the third sub-heat transfer layer. The third sub-heat transfer layer conducts heat directly to the bottom of the laser 402 through the via 409.

[0084] 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 dielectric layer. In this way, the first heat transfer layer 410, the second heat transfer layer 412 and the filling layer 411 can all conduct heat to the laser 402, making the heat transfer efficiency to the laser 402 faster.

[0085] Figure 10 A schematic diagram of a partial structure of the circuit board in the optical module provided in this application embodiment. Figure 1 , Figure 11 A schematic diagram of a partial structure of the circuit board in the optical module provided in this application embodiment. Figure 2 .like Figure 10 , Figure 11 As shown, 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 exposed filling layer 411 at the mounting groove 408 is provided with a metal via 409.

[0086] 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 vias 409 are provided between the first heat transfer layer 410 and the second heat transfer layer 412, and the first heat transfer layer 410 conducts heat to the second heat transfer layer 412 through the vias 409.

[0087] In some embodiments, a metal layer is further disposed on the upper surface of the circuit board 300, on which optoelectronic devices such as the laser driver chip 401, transimpedance amplifier, and MCU are disposed. However, there is a gap between the metal layer and the first heat transfer layer 410 to prevent the heat conducted by the first heat transfer layer 410 from diffusing onto the metal layer, so that the heat is conducted on the first heat transfer layer 410 as much as possible, and to prevent the heat from heating other optoelectronic devices on the metal layer and affecting the performance of other optoelectronic devices.

[0088] Figure 12 Schematic diagram of heat transfer on the circuit board of the optical module provided in the embodiments of this application Figure 1 , Figure 13 Schematic diagram of heat transfer on the circuit board of the optical module provided in the embodiments of this application Figure 2 , Figure 14 Schematic diagram of heat transfer on the circuit board of the optical module provided in the embodiments of this application Figure 3 .like Figure 12 , Figure 13 , Figure 14 As shown, 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, and then the second sub-heat transfer layer 407 conducts the heat to the first sub-heat transfer layer 406. The first sub-heat transfer layer 406 radiates the heat to the laser 402 by thermal radiation, and thus the first heat transfer layer 410 radiates the heat to the laser 402.

[0089] Since the second heat transfer layer 412 is connected to the first heat transfer layer 410 through the via 409, the heat from the second sub-heat transfer layer 407 is conducted to the fourth sub-heat transfer layer of the second heat transfer layer 412 through the via 409, and the heat from the first sub-heat transfer layer 406 is conducted to the third sub-heat transfer layer of the second heat transfer layer 412 through the via 409. At the same time, the fourth sub-heat transfer layer conducts heat to the third sub-heat transfer layer, and the third sub-heat transfer layer conducts heat directly to the bottom of the laser 402 through the via 409. In this way, the second heat transfer layer 412 conducts heat to the laser 402.

[0090] The optical module provided in this application includes a circuit board, a laser driver chip, a laser, and a heating resistor. The circuit board includes a first heat transfer layer, a second heat transfer layer, and a filler layer. The first heat transfer layer is located on the upper surface of the circuit board, and the laser driver chip is disposed on the upper surface of the circuit board. A gap exists between the first heat transfer layer and the laser driver chip to prevent the first heat transfer layer from connecting to the laser driver chip, thereby preventing heat conduction to the laser driver chip. The first heat transfer layer covers the projection area of ​​the laser and the heating resistor on the circuit board, and the laser is disposed on the first heat transfer layer. The laser is electrically connected to the laser driver chip via wire bonding to generate an optical signal according to the driving current provided by the laser driver chip. A through mounting groove is provided on the first heat transfer layer, and a metal via is provided between the exposed filler layer of the mounting groove and the second heat transfer layer. The device is mounted on the metal vias of the filler layer, allowing the laser to connect to the second heat transfer layer through the vias. A gap exists between the laser and the inner wall of the mounting groove to prevent adhesive from flowing onto the first heat transfer layer. A heating resistor is located above the first heat transfer layer, providing power to the optical module when it is at a low temperature. Heat is conducted through the first heat transfer layer to the laser to heat it. The second heat transfer layer is located below the first heat transfer layer, with multiple vias between them. The second heat transfer layer connects to the laser through these vias, allowing the first heat transfer layer to conduct heat to the second heat transfer layer, which in turn conducts heat to the laser. A filler layer is located between the first and second heat transfer layers, connecting them. This application sets a first heat transfer layer and a second heat transfer layer on the circuit board. The laser is located on the first heat transfer layer, and the heating resistor is located above the first heat transfer layer. The first heat transfer layer is connected to the second heat transfer layer through vias. Thus, when the laser in the optical module is at a low temperature, the heat generated by the heating resistor is conducted to the first heat transfer layer. The first heat transfer layer radiates the heat to the laser through thermal radiation. At the same time, the first heat transfer layer conducts some of the heat to the second heat transfer layer through vias. The second heat transfer layer directly conducts the heat to the laser through vias. In this way, the heat from the heating resistor is conducted to the laser through thermal radiation and thermal conduction, which increases the amount of heat conducted from the heating resistor to the laser, improves the heat transfer efficiency, maintains the operating temperature of the laser, and avoids the adverse effects of low temperature environment on laser performance.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. An optical module, characterized in that, include: Circuit board; A laser driver chip is mounted on the circuit board; The laser is attached to the circuit board, and its top surface is electrically connected to the laser driver chip via wire bonding. A heating resistor, electrically connected to the circuit board, is used to heat the laser at low temperatures; The circuit board includes: A first heat transfer layer is located on the upper surface of the circuit board and has a gap with the laser driving chip; the laser is disposed on the first heat transfer layer, and the heating resistor is located above the first heat transfer layer; it is used to conduct the heat generated by the heating resistor to the laser; the heating resistor includes a first electrode and a second electrode, and there is a gap between the first heat transfer layer and the first electrode and the second electrode; the first heat transfer layer covers the projection area of ​​the laser and the heating resistor on the circuit board; The second heat transfer layer is located below the first heat transfer layer and has multiple vias between it and the first heat transfer layer. It is connected to the laser through the vias and is used to conduct heat conducted through the vias to the laser. The filler layer is located between the first heat transfer layer and the second heat transfer layer and is used to connect the first heat transfer layer and the second heat transfer layer. The first heat transfer layer is provided with a through mounting groove, and the mounting groove has an opening on the side facing the laser driver chip; the laser is located on the filling layer exposed at the mounting groove, and there is a gap between the laser and the inner wall of the mounting groove.

2. The optical module according to claim 1, characterized in that, The first heat transfer layer includes 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 to the second sub-heat transfer layer. The heating resistor is located above the second sub-heat transfer layer.

3. The optical module according to claim 2, characterized in that, The length of the first sub-heat transfer layer in the left-right direction is greater than that of the second sub-heat transfer layer in the left-right direction, and the heat transfer area of ​​the first sub-heat transfer layer is greater than that of the second sub-heat transfer layer.

4. The optical module according to claim 2, characterized in that, The first electrode and the second electrode are electrically connected to the circuit board, and the heating resistor is located on the first electrode and the second electrode. The heating resistor is powered and heated through the first electrode and the second electrode. There is a gap between the first electrode and the second electrode, the second sub-heat transfer layer is located in the gap, and there are gaps between the first electrode, the second electrode and the first sub-heat transfer layer, and the second sub-heat transfer layer.

5. The optical module according to claim 4, characterized in that, A metal via is provided on the exposed filling layer at the mounting groove, the laser is disposed on the metal via, and the metal via is connected to the second heat transfer layer.

6. The optical module according to claim 1, characterized in that, Both the first heat transfer layer and the second heat transfer layer are T-shaped.

7. The optical module according to claim 1, characterized in that, Both the first heat transfer layer and the second heat transfer layer are heat transfer copper layers, and the vias are copper vias.

8. The optical module according to claim 1, characterized in that, The filler layer is a resin medium layer.

9. The optical module according to claim 1, characterized in that, It also includes a temperature sensor, which is mounted on the circuit board and is used to collect the operating temperature of the laser inside the optical module.

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