Optical module

Abstract

Provided in the embodiments of the present disclosure is an optical module, comprising: a circuit board, which is provided with a digital signal processing assembly, a depressed area being formed on the surface of the circuit board; and an optical receiving component, comprising an optical receiving chip which is configured to receive an optical signal and is located in the depressed area, the difference between the depth of the depressed area and the thickness of the optical receiving chip being within a first preset range, such that the height difference between a high-frequency signal pin of the optical receiving chip and a signal connection end of the digital signal processing assembly is within the first preset range, wherein the signal connection end of the digital signal processing assembly and the depressed area are located on the same surface of the circuit board. The optical module further comprises a receiving bottom board, which is embedded in the depressed area, the optical receiving component being located on the receiving bottom board, and the elastic modulus of the receiving bottom board being greater than that of the circuit board.

Description

optical modules

[0001] This application claims the priority of application number 202321698812.9 filed with the China Patent Office on June 29, 2023; the priority of application number 202321695259.3 filed with the China Patent Office on June 29, 2023; and the priority of application number 202322263386.2 filed with the China Patent Office on August 22, 2023; all of which are incorporated by reference into this application. Technical Field

[0002] The present disclosure relates to the field of optical fiber communication technology, and in particular to an optical module. Background Art

[0003] With the development of new services and applications such as cloud computing, mobile internet, and video, advances in optical communication technology are becoming increasingly important. In optical communication technology, optical modules are tools for converting optical and electrical signals, and are key components in optical communication equipment. Furthermore, with the advancement of optical communication technology, the transmission rate of optical modules is required to continue to increase.

[0004] Summary of the Invention

[0005] An embodiment of the present disclosure provides an optical module, including:

[0006] A circuit board, wherein the circuit board is provided with a digital signal processing component, and a recessed area is formed on the surface of the circuit board;

[0007] The light receiving component includes a light receiving chip configured to receive an optical signal;

[0008] The optical receiving chip is located in the recessed area; the difference between the recessed depth of the recessed area and the thickness of the optical receiving chip is within a first preset range, so that the height difference between the high-frequency signal pin of the optical receiving chip and the signal connection end of the digital signal processing component is within the first preset range; wherein the signal connection end of the digital signal processing component and the recessed area are located on the same surface of the circuit board;

[0009] The optical module further includes a receiving base plate, the receiving base plate is embedded in the recessed area, the light receiving component is located on the receiving base plate, and the elastic modulus of the receiving base plate is greater than the elastic modulus of the circuit board. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0011] FIG1 is a partial architecture diagram of an optical communication system provided according to some embodiments of the present disclosure;

[0012] FIG2 is a partial structural diagram of a host computer provided according to some embodiments of the present disclosure;

[0013] FIG3 is a structural diagram of an optical module provided according to some embodiments of the present disclosure;

[0014] FIG4 is an exploded view of an optical module according to some embodiments of the present disclosure;

[0015] FIG5 is a structural diagram of an optical module provided by some embodiments of the present disclosure without a housing and an unlocking component;

[0016] FIG6 is an exploded schematic diagram of a circuit board and a lens assembly in an optical module according to some embodiments of the present disclosure;

[0017] FIG7 is a schematic diagram of the structure of a light emitting chip and a circuit board according to some embodiments of the present disclosure;

[0018] FIG8 is a schematic diagram of stress generated by heat on a light emitting chip and a circuit board according to some embodiments of the present disclosure;

[0019] FIG9 is a schematic diagram illustrating stress generated by a light emitting chip and a circuit board due to cold conditions according to some embodiments of the present disclosure;

[0020] FIG10 is a cross-sectional diagram of a light emitting chip and a circuit board according to some embodiments of the present disclosure;

[0021] FIG11 is a cross-sectional schematic diagram of a light receiving component, a receiving base plate, and a circuit board according to some embodiments of the present disclosure;

[0022] FIG12 is an exploded view of a light receiving component and a circuit board according to some embodiments of the present disclosure;

[0023] FIG13 is an assembly diagram of some components of a light receiving component and a circuit board according to some embodiments of the present disclosure;

[0024] FIG14a is an assembly diagram of some components of a light receiving component and a circuit board from another perspective according to some embodiments of the present disclosure;

[0025] FIG14 b is another assembly diagram of some components of a light receiving component and a circuit board according to some embodiments of the present disclosure;

[0026] FIG15 is a structural diagram of another optical module provided according to some embodiments of the present disclosure without a housing and an unlocking component;

[0027] FIG16 is a structural diagram of another optical module provided by some embodiments of the present disclosure, with the housing and unlocking components removed, viewed from another perspective;

[0028] FIG17 is an assembly diagram of some components of a light receiving component and a circuit board according to some embodiments of the present disclosure;

[0029] FIG18 is a structural diagram of a via provided according to some embodiments of the present disclosure;

[0030] FIG19 is a cross-sectional diagram of a light receiving component and a circuit board according to some embodiments of the present disclosure;

[0031] FIG20 is a schematic diagram of an exploded view of a light receiving component and a circuit board according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0032] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in some embodiments of the present disclosure. Obviously, the embodiments described are only some embodiments of the present disclosure, not all embodiments. Based on the embodiments provided by the present disclosure, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of the present disclosure.

[0033] Unless the context requires otherwise, throughout the specification and claims, the term "comprise" and its other forms, such as the third person singular form "comprises" and the present participle form "comprising", are to be interpreted as open and inclusive, that is, "including, but not limited to". In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiments", "example", "specific example" or "some examples" are intended to indicate that the particular features, structures, materials or characteristics associated with the embodiment or example are included in at least one embodiment or example of the present disclosure. The schematic representation of the above terms does not necessarily refer to the same embodiment or example. In addition, the particular features, structures, materials or characteristics may be included in any one or more embodiments or examples in any appropriate manner.

[0034] In the following, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present disclosure, unless otherwise specified, "plurality" means two or more.

[0035] When describing some embodiments, the expressions "coupled" and "connected" and their derivatives may be used. For example, when describing some embodiments, the term "connected" may be used to indicate that two or more components are in direct physical or electrical contact with each other. For another example, when describing some embodiments, the term "coupled" may be used to indicate that two or more components are in direct physical or electrical contact. However, the term "coupled" or "communicatively coupled" may also refer to two or more components that are not in direct contact with each other, but still cooperate or interact with each other. The embodiments disclosed herein are not necessarily limited to the contents of this document.

[0036] “At least one of A, B and C” has the same meaning as “at least one of A, B or C” and both include the following combinations of A, B and C: A only, B only, C only, the combination of A and B, the combination of A and C, the combination of B and C, and the combination of A, B and C.

[0037] “A and / or B” includes the following three combinations: A only, B only, and a combination of A and B.

[0038] The use of "adapted to" or "configured to" herein is intended to be open and inclusive language that does not exclude devices adapted or configured to perform additional tasks or steps.

[0039] As used herein, "about," "substantially," or "approximately" includes the stated value and an average value that is within an acceptable range of deviation from the particular value as determined by one of ordinary skill in the art taking into account the measurements in question and the errors associated with the measurement of the particular quantity (i.e., the limitations of the measurement system).

[0040] Optical communication technology enables information transmission between information processing devices. It loads information onto light and uses the propagation of light to achieve this transmission. Light loaded with information is an optical signal. The propagation of optical signals within information transmission equipment reduces optical power loss, enabling high-speed, long-distance, and low-cost information transmission. The information processed by information processing equipment exists in the form of electrical signals. Optical network terminals / gateways, routers, switches, mobile phones, computers, servers, tablets, and televisions are common information processing devices, and optical fibers and optical waveguides are common information transmission devices.

[0041] The conversion of optical signals and electrical signals between information processing equipment and information transmission equipment is achieved through optical modules. For example, an optical fiber is connected to the optical signal input end and / or optical signal output end of the optical module, and an optical network terminal is connected to the electrical signal input end and / or electrical signal output end of the optical module. A first optical signal from the optical fiber is transmitted into the optical module, and the optical module converts the first optical signal into a first electrical signal, which is then transmitted into the optical network terminal. A second electrical signal from the optical network terminal is transmitted into the optical module, and the optical module converts the second electrical signal into a second optical signal, which is then transmitted into the optical fiber. Since information processing devices can be connected to each other through an electrical signal network, at least one type of information processing device needs to be directly connected to the optical module, and not all types of information processing devices need to be directly connected to the optical module. The information processing device directly connected to the optical module is called the host computer of the optical module.

[0042] Figure 1 is a partial architecture diagram of an optical communication system according to some embodiments of the present disclosure. As shown in Figure 1, the optical communication system partially comprises a remote information processing device 1000, a local information processing device 2000, a host computer 100, an optical module 200, an optical fiber 101, and a network cable 103.

[0043] One end of optical fiber 101 extends toward remote information processing device 1000, and the other end connects to the optical interface of optical module 200. Optical signals can undergo total internal reflection within optical fiber 101, maintaining nearly their original optical power as they propagate in the direction of total internal reflection. Multiple total internal reflections within optical fiber 101 transmit optical signals from the direction of remote information processing device 1000 into optical module 200, or transmit light from optical module 200 toward remote information processing device 1000, enabling long-distance, low-power information transmission.

[0044] The number of optical fibers 101 may be one or more (two or more); the optical fiber 101 and the optical module 200 may be connected in a pluggable movable manner or in a fixed manner.

[0045] The host computer 100 has an optical module interface 102, which is configured to connect to the optical module 200, so that the host computer 100 establishes a unidirectional / bidirectional electrical signal connection with the optical module 200; the host computer 100 is configured to provide data signals to the optical module 200, or receive data signals from the optical module 200, or monitor and control the working status of the optical module 200.

[0046] The host computer 100 has an external electrical interface, such as a Universal Serial Bus (USB) interface and a network cable interface 104, which can be connected to an electrical signal network. For example, the network cable interface 104 is configured to connect to a network cable 103, thereby establishing a unidirectional / bidirectional electrical signal connection between the host computer 100 and the network cable 103.

[0047] Optical Network Unit (ONU), Optical Line Terminal (OLT), Optical Network Equipment (ONT) and data center servers are common host computers.

[0048] One end of the network cable 103 is connected to the local information processing device 2000 , and the other end is connected to the host computer 100 . The network cable 103 establishes an electrical signal connection between the local information processing device 2000 and the host computer 100 .

[0049] For example, the third electrical signal emitted by the local information processing device 2000 is transmitted to the host computer 100 through the network cable 103. The host computer 100 generates a second electrical signal based on the third electrical signal. The second electrical signal from the host computer 100 is transmitted into the optical module 200. The optical module 200 converts the second electrical signal into a second optical signal. The optical module 200 transmits the second optical signal into the optical fiber 101. The second optical signal is transmitted to the remote information processing device 1000 in the optical fiber 101.

[0050] For example, a first optical signal from the direction of the remote information processing device 1000 propagates through the optical fiber 101, and the first optical signal from the optical fiber 101 is transmitted into the optical module 200. The optical module 200 converts the first optical signal into a first electrical signal. The optical module 200 transmits the first electrical signal into the host computer 100. The host computer 100 generates a fourth electrical signal based on the first electrical signal, and the host computer 100 transmits the fourth electrical signal to the local information processing device 2000.

[0051] Optical modules are tools for converting optical signals into electrical signals. During this conversion process, the information remains unchanged, but the encoding and decoding methods of the information can change.

[0052] FIG2 is a partial structural diagram of a host computer provided according to some embodiments of the present disclosure. In order to clearly illustrate the connection relationship between the optical module 200 and the host computer 100, FIG2 only shows the structure of the host computer 100 related to the optical module 200. As shown in FIG2, the host computer 100 also includes a PCB circuit board 105 disposed within the housing, a cage 106 disposed on the surface of the PCB circuit board 105, a heat sink 107 disposed on the cage 106, and an electrical connector (not shown) disposed inside the cage 106. The heat sink 107 has a raised structure that increases the heat dissipation area. A fin-like structure is a common raised structure.

[0053] Optical module 200 is inserted into cage 106 of host computer 100. Cage 106 secures optical module 200, and heat generated by optical module 200 is transferred to cage 106 and then dissipated through heat sink 107. After optical module 200 is inserted into cage 106, the electrical interface of optical module 200 connects to the electrical connector inside cage 106.

[0054] Figure 3 is a structural diagram of an optical module provided according to some embodiments of the present disclosure. Figure 4 is an exploded view of an optical module provided according to some embodiments of the present disclosure. As shown in Figures 3 and 4, the optical module 200 includes a housing, a circuit board 300 disposed within the housing, a light emitting component 400, and a light receiving component 500. However, the present disclosure is not limited thereto. In some embodiments, the optical module 200 includes either the light emitting component 400 or the light receiving component 500.

[0055] The housing includes an upper housing 201 and a lower housing 202 . The upper housing 201 covers the lower housing 202 to form the housing having two openings 204 and 205 . The outer contour of the housing is generally a square.

[0056] In some embodiments, the lower shell 202 includes a base plate 2021 and two lower side plates 2022 located on both sides of the base plate 2021 and arranged perpendicular to the base plate 2021; the upper shell 201 includes a cover plate 2011, and the cover plate 2011 covers the two lower side plates 2022 of the lower shell 202 to form the above-mentioned shell.

[0057] In some embodiments, the lower shell 202 includes a base plate 2021 and two lower side plates 2022 located on both sides of the base plate 2021 and arranged perpendicularly to the base plate 2021; the upper shell 201 includes a cover plate 2011 and two upper side plates located on both sides of the cover plate 2011 and arranged perpendicularly to the cover plate 2011. The two upper side plates are combined with the two lower side plates 2022 to achieve the upper shell 201 covering the lower shell 202.

[0058] The direction of the line connecting the two openings 204 and 205 can be aligned with or inconsistent with the length of the optical module 200. For example, opening 204 is located at the end of the optical module 200 (the right end in FIG3 ), and opening 205 is also located at the end of the optical module 200 (the left end in FIG3 ). Alternatively, opening 204 is located at the end of the optical module 200, while opening 205 is located on the side of the optical module 200. Opening 204 is an electrical interface, from which the gold fingers of the circuit board 300 extend and are inserted into the electrical connector of the test host. Opening 205 is an optical port, configured to receive the optical fiber 101, so that the optical fiber 101 can connect to the optical emitting component 400 and / or the optical receiving component 500 in the optical module 200.

[0059] The combined assembly of the upper and lower housings 201 and 202 facilitates the installation of components such as the circuit board 300, light emitting component 400, and light receiving component 500 within the housings. These components are encapsulated and protected by the upper and lower housings 201 and 202. Furthermore, during assembly of the circuit board 300, light emitting component 400, and light receiving component 500, positioning components, heat dissipation components, and electromagnetic shielding components are easily positioned, facilitating automated production.

[0060] In some embodiments, the upper shell 201 and the lower shell 202 are made of metal materials, which facilitates electromagnetic shielding and heat dissipation.

[0061] In some embodiments, the optical module 200 further includes an unlocking component 600 located outside its housing. The unlocking component 600 is configured to achieve a fixed connection between the optical module 200 and the test host, or to release the fixed connection between the optical module 200 and the test host.

[0062] For example, the unlocking member 600 is located on the outside of the two lower side panels 2022 of the lower housing 202 and includes engaging components that mate with the cage 106 of the test host. When the optical module 200 is inserted into the cage 106, the engaging components of the unlocking member 600 secure the optical module 200 within the cage 106. When the unlocking member 600 is pulled, the engaging components of the unlocking member 600 move accordingly, thereby changing the connection between the engaging components and the test host, releasing the fixed engagement between the optical module 200 and the test host, and allowing the optical module 200 to be removed from the cage 106.

[0063] The circuit board 300 includes circuit traces, electronic components, and chips. The electronic components and chips are connected together according to the circuit design through the circuit traces to achieve functions such as power supply, electrical signal transmission, and grounding. Electronic components may include, for example, capacitors, resistors, transistors, and metal-oxide-semiconductor field-effect transistors (MOSFETs). Chips may include, for example, microcontroller units (MCUs), laser driver chips, transimpedance amplifiers (TIAs), limiting amplifiers, clock and data recovery chips (CDRs), power management chips, and digital signal processing (DSP) chips.

[0064] The circuit board 300 is generally a rigid circuit board. Due to its relatively hard material, the rigid circuit board can also realize the load-bearing function. For example, the rigid circuit board can stably carry the above-mentioned electronic components and chips; the rigid circuit board is also easy to insert into the electrical connector in the test host cage.

[0065] The circuit board 300 also includes gold fingers formed on its end surfaces. These gold fingers consist of multiple independent pins. The circuit board 300 is inserted into the cage 106, with the gold fingers providing electrical connection to the electrical connector within the cage 106. The gold fingers can be located only on one side of the circuit board 300 (e.g., the top surface shown in FIG4 ), or on both the top and bottom surfaces of the circuit board 300 to provide more pins. The gold fingers are configured to establish an electrical connection with the test host to provide power, grounding, I2C signal transmission, data signal transmission, and the like.

[0066] Of course, flexible circuit boards are also used in some optical modules. Flexible circuit boards are generally used in conjunction with rigid circuit boards to supplement rigid circuit boards.

[0067] The light emitting component 400 and / or the light receiving component 500 are located on the side of the circuit board 300 away from the gold finger; in some embodiments, the light emitting component 400 and the light receiving component 500 are physically separated from the circuit board 300, and then electrically connected to the circuit board 300 through corresponding flexible circuit boards or electrical connectors; in some embodiments, the light emitting component and / or the light receiving component can be directly set on the circuit board 300, can be set on the surface of the circuit board, and can also be set on the side of the circuit board.

[0068] Figure 5 is a structural diagram of an optical module provided in accordance with some embodiments of the present disclosure, excluding the housing and unlocking components. As shown in Figure 5, in some embodiments, the circuit board 300 has a card interface, and the optical emitting component 400 is snapped onto the card interface. The optical emitting component 400 is used to transmit optical signals.

[0069] In some embodiments, the optical emitting component 400 includes an emitting cavity, which is internally provided with a laser array, a lens array, and an optical multiplexing assembly. The laser array emits multiple optical signals, the lens array collimates the multiple optical signals, and the optical multiplexing assembly combines the collimated multiple optical signals into one optical signal, which is then transmitted to the outside via optical fiber. For example, the laser array includes four lasers, and the corresponding lens array includes four collimating lenses. The laser array emits four optical signals, which respectively enter the four collimating lenses and are then combined into one optical signal by the optical multiplexing assembly. The one optical signal is then transmitted to the outside of the optical module.

[0070] To more clearly describe the components of the optical transmitter assembly, FIG6 is a schematic diagram of an exploded view of a circuit board and a lens assembly in an optical module provided according to some embodiments of the present disclosure. As shown in FIG5 and FIG6, the lens assembly 410 (also referred to as a lens array) provided in the present application is arranged on the circuit board 300, and is covered above the optical chip on the circuit board 300 in a cover-type manner (the optical chip mainly refers to the optical transmitter chip 420, the driver chip 430, the optical receiver chip, the transimpedance amplifier chip, the limiting amplifier chip and other chips related to the photoelectric conversion function). The lens assembly 410 and the circuit board 300 form a cavity that encapsulates the optical chip such as the optical transmitter chip. The lens assembly 410 and the circuit board 300 together form a structure for encapsulating the optical chip. The light emitted by the optical transmitter chip is reflected by the lens assembly 410 and enters the optical fiber array. The lens assembly 410 establishes a mutual optical connection between the optical transmitter chip 420 (i.e., the laser array) and the optical fiber array. The lens assembly 410 not only seals the optical chip, but also establishes an optical connection between the optical chip and the optical fiber array.

[0071] Figure 7 is a schematic diagram of the optical transmitter chip and circuit board structure provided in accordance with some embodiments of the present disclosure. As shown in Figure 7, the optical transmitter chip is located between the lens assembly 410 and the circuit board 300, and the optical transmitter chip 420 is connected to the circuit board. The optical signal emitted from the top surface of the optical transmitter chip 420 is redirected by the lens assembly 410 and then enters the optical fiber array. When the temperature of the optical module changes, the circuit board expands or contracts due to the temperature, causing stress on the optical transmitter chip along its length.

[0072] FIG8 is a schematic diagram of stress generated by heat on the optical emission chip and the circuit board according to some embodiments of the present disclosure. As shown in FIG8, when the optical module is heated and the temperature rises, the circuit board expands along the length direction (the X direction in the figure), causing the optical emission chip to bear stress in the length direction, and the bit error rate of the optical emission chip increases, affecting the transmission of light. FIG9 is a schematic diagram of stress generated by cold on the optical emission chip and the circuit board according to some embodiments of the present disclosure. As shown in FIG9, when the optical module is cooled and the temperature drops, the circuit board contracts along the length direction (the X direction in the figure), causing the optical emission chip to bear stress in the length direction, and the bit error rate of the optical emission chip increases, affecting the transmission of light.

[0073] FIG10 is a schematic cross-sectional view of an optical transmitter chip and a circuit board provided according to some embodiments of the present disclosure. As shown in FIG10 , in order to reduce the bit error rate of the optical module, the optical module provided by the present disclosure is provided with an emission panel, and the emission panel 306 is embedded in the interior of the circuit board. The optical transmitter chip is located above the emission panel 306. The difference between the thermal expansion coefficient of the emission panel 306 and the thermal expansion coefficient of the optical transmitter chip is less than the difference between the thermal expansion coefficient of the circuit board and the thermal expansion coefficient of the optical transmitter chip. Therefore, when the temperature rises or falls, the thermal expansion or cold contraction of the emission panel 306 and the optical transmitter chip remain consistent, effectively reducing the stress on the optical transmitter chip, reducing the bit error rate, and improving the reliability of the optical module in high and low temperature environments. The circuit board has an emission through hole 305, and the emission panel 306 is embedded in the emission through hole 305.

[0074] For example, the emission through hole 305 can also be an emission blind hole, that is, the emission panel 306 does not penetrate the upper and lower surfaces of the circuit board. The lower part of the emission panel 306 is connected to the circuit board, and the thickness of the circuit board is reduced below the emission panel 306. The lower surface of the emission panel is connected to the bottom of the emission blind hole.

[0075] For example, the ratio of the difference between the thermal expansion coefficient of the transmitting panel 306 and the thermal expansion coefficient of the light emitting chip to the difference between the thermal expansion coefficient of the circuit board and the thermal expansion coefficient of the light emitting chip is less than 70%. When the temperature of the optical module increases or decreases, the difference between the thermal expansion of the transmitting panel 306 and the thermal expansion coefficient of the light emitting chip is less than the difference between the thermal expansion of the circuit board and the thermal expansion coefficient of the light emitting chip. This reduces stress on the light emitting chip, lowers the bit error rate, and improves the reliability of the optical module in high and low temperature environments.

[0076] For example, the ratio of the difference between the thermal expansion coefficient of the transmitting panel 306 and the thermal expansion coefficient of the light emitting chip to the difference between the thermal expansion coefficient of the circuit board and the thermal expansion coefficient of the light emitting chip is less than 50%. When the temperature of the optical module increases or decreases, the difference between the thermal expansion of the transmitting panel 306 and the thermal expansion coefficient of the light emitting chip is less than the difference between the thermal expansion of the circuit board and the thermal expansion coefficient of the light emitting chip. This reduces stress on the light emitting chip, lowers the bit error rate, and improves the reliability of the optical module in high and low temperature environments.

[0077] For example, the ratio of the difference between the thermal expansion coefficient of the emitting panel 306 and the thermal expansion coefficient of the light emitting chip to the difference between the thermal expansion coefficient of the circuit board and the thermal expansion coefficient of the light emitting chip is less than 30%. The ratio of the difference between the thermal expansion coefficient of the emitting panel 306 and the thermal expansion coefficient of the light emitting chip to the difference between the thermal expansion coefficient of the circuit board 300 and the thermal expansion coefficient of the light emitting chip is less than 30%. When the temperature of the optical module increases or decreases, the difference between the thermal expansion of the emitting panel 306 and the thermal expansion of the light emitting chip is less than the difference between the thermal expansion of the circuit board 300 and the thermal expansion of the light emitting chip. This reduces stress on the light emitting chip, lowers the bit error rate, and improves the reliability of the optical module in high and low temperature environments.

[0078] For example, the difference between the thermal expansion coefficient of the emitting panel 306 and the thermal expansion coefficient of the light emitting chip is zero, meaning the thermal expansion coefficient of the emitting panel 306 is the same as the thermal expansion coefficient of the light emitting chip. This difference between the thermal expansion coefficients of the emitting panel 306 and the light emitting chip allows the emitting panel 306 to expand by the same amount as the light emitting chip when the temperature of the optical module increases or decreases. This reduces stress on the light emitting chip, lowers the bit error rate, and improves the reliability of the optical module in high and low temperature environments.

[0079] The area of ​​the emitting panel 306 is larger than that of the light emitting chip, so that the entire light emitting chip is located above the emitting panel 306. In some examples of the present disclosure, the optical module includes a first light emitting chip 421 and a second light emitting chip 422, both of which are located above the emitting panel 306. The projection of the first light emitting chip 421 on the emitting panel 306 has a minimum distance from the circuit board 300 greater than or equal to 0.35 mm. This reduces the impact of thermal expansion or contraction of the circuit board 300 on the emitting panel 306 when heated or cooled, reduces the stress on the first light emitting chip 421 caused by deformation of the circuit board 300, reduces the bit error rate of the first light emitting chip 421, and improves reliability in high and low temperature environments.

[0080] The projection of the second light emitting chip 422 on the emission panel 306 has a minimum distance from the circuit board 300 of greater than or equal to 0.35 mm. This reduces the impact of thermal expansion or contraction of the circuit board 300 on the emission panel 306 when heated or cooled, reduces the stress on the second light emitting chip 422 caused by the deformation of the circuit board 300, reduces the bit error rate of the first light emitting chip 421, and improves reliability in high and low temperature environments.

[0081] In some embodiments, the maximum distance between the projection of the first light emitting chip 421 on the emitting panel 306 and the circuit board 300 is less than or equal to 1.5 mm. This reduces the stress caused by thermal expansion or contraction of the circuit board 300 when heated or cooled, reduces the stress on the first light emitting chip 421 due to deformation of the circuit board 300, reduces the bit error rate of the first light emitting chip 421, and improves reliability in high and low temperature environments. Reducing the space occupied by the emitting panel 306 on the circuit board 300 facilitates miniaturization of the optical module. The maximum distance between the projection of the second light emitting chip 422 on the emitting panel 306 and the circuit board 300 is less than or equal to 1.5 mm. This reduces the stress caused by thermal expansion or contraction of the circuit board 300 when heated or cooled, reduces the stress on the second light emitting chip 422 due to deformation of the circuit board 300, reduces the bit error rate of the second light emitting chip 422, and improves reliability in high and low temperature environments. Reducing the space occupied by the emission panel 306 on the circuit board 300 is beneficial to miniaturization of the optical module.

[0082] As shown in Figure 10, in some embodiments, the optical module further includes laser driver chips, including a first laser driver chip 431 and a second laser driver chip 432. To facilitate driving the light emitting chip, one end of the laser driver chip is located above the emitting panel 306, and the laser driver chip and the light emitting chip are wire-bonded. For example, the first end of the first laser driver chip 431 is located above the emitting panel 306, and the first laser driver chip 431 is wire-bonded to the first light emitting chip 421. To electrically connect the first laser driver chip 431, the second end of the first laser driver chip 431 is located on the circuit board 300 and electrically connected to the circuit board 300. A portion of the first laser driver chip 431 is located above the emitting panel 306, and another portion is located above the circuit board 300, and the first laser driver chip 431 is connected to the first light emitting chip 421.

[0083] To facilitate the connection between the first light emitting chip 421 and the first laser driver chip 431, an output pad is provided on the upper surface of the first end of the first laser driver chip 431. The upper surface of the first light emitting chip 421 is also provided with an emission pad, which is connected to the emission pad via wire bonding. To facilitate the connection between the circuit board 300 and the first laser driver chip 431, an input pad is provided on the lower surface of the second end of the first laser driver chip 431. Drive pins are provided on the upper surface of the circuit board 300. The drive pins are connected to the input pads to receive electrical signals from the circuit board 300.

[0084] To facilitate driving the light emitting chip, the first end of the second laser driver chip 432 is located above the emission panel 306, and the second laser driver chip 432 is wire-bonded to the second light emitting chip 422. To achieve electrical connection to the second laser driver chip 432, the second end of the second laser driver chip 432 is located on the circuit board 300 and electrically connected to the circuit board 300. A portion of the second laser driver chip 432 is located above the emission panel 306, and another portion is located above the circuit board 300. The second laser driver chip 432 is connected to the second light emitting chip 422.

[0085] To facilitate the connection between the second light-emitting chip 422 and the second laser driver chip 432, an output pad is provided on the upper surface of the first end of the second laser driver chip 432. The upper surface of the second light-emitting chip 422 is also provided with an emission pad, which is connected to the emission pad via wire bonding. To facilitate the connection between the circuit board 300 and the first laser driver chip 431, an input pad is provided on the lower surface of the second end of the second laser driver chip 432. A drive pin is provided on the upper surface of the circuit board 300. The drive pin is connected to the input pad to receive electrical signals from the circuit board 300.

[0086] The emitting panel 306 can be a cylindrical structure, or an irregular three-dimensional structure or a square structure. To facilitate the installation of the emitting panel 306 and the circuit board 300, the emitting panel 306 is a rectangular cube with four corners having arc chamfers.

[0087] The top surface of emitter panel 306 is no higher than the top surface of circuit board 300, and the difference in thickness between emitter panel 306 and circuit board 300 is less than 0.05 mm, facilitating fabrication. In some embodiments, circuit board 300 is provided with an emitter through-hole, into which emitter panel 306 is embedded. Emitter panel 306 can be made of aluminum nitride.

[0088] In some embodiments of the present disclosure, the light emitting chip may be an edge emitting laser or a vertical cavity surface emitting laser, wherein the light emitting surface of the vertical cavity surface emitting laser faces the upper housing.

[0089] The present disclosure provides an optical module comprising: a circuit board 300 and a lens assembly disposed above the circuit board 300. A light emitting chip is disposed between the circuit board 300 and the lens assembly. The circuit board 300 is provided with an emitting through-hole, and an emitting panel 306 is disposed within the emitting through-hole. The light emitting chip is disposed above the emitting panel 306. The difference between the thermal expansion coefficient of the emitting panel 306 and the thermal expansion coefficient of the light emitting chip is smaller than the difference between the thermal expansion coefficients of the circuit board 300 and the thermal expansion coefficient of the light emitting chip. Therefore, when the temperature rises or falls, the difference in thermal expansion or contraction between the emitting panel 306 and the light emitting chip is smaller than the difference in thermal expansion or contraction between the circuit board 300 and the light emitting chip. This effectively reduces stress on the light emitting chip, lowers the bit error rate, and improves the reliability of the optical module in high and low temperature environments. The entire projection of the light emitting chip 420 onto the emitting panel 306 is located within the emitting panel 306. One end of the laser driver chip 430 is located above the emitting panel 306, and the laser driver chip is wire-bonded to the light emitting chip. The other end of the laser driving chip 430 is located above the circuit board 300 , and the laser driving chip is connected to the circuit board 300 by wire bonding.

[0090] The minimum distance between the projection of the light emitting chip on the emitting panel 306 and the circuit board 300 is greater than or equal to 0.35 mm. This reduces the impact of thermal expansion or thermal contraction of the circuit board 300 on the emitting panel 306 when heated or cooled, reduces the stress on the light emitting chip caused by the deformation of the circuit board 300, reduces the bit error rate of the light emitting chip, and improves reliability in high and low temperature environments.

[0091] A circuit board, wherein the circuit board is provided with a digital signal processing component;

[0092] Figure 11 is a cross-sectional schematic diagram of an optical receiving component 500, a receiving base plate 307, and a circuit board 300, according to some embodiments of the present disclosure. As shown in Figure 11, a digital signal processing component is disposed on the surface of the circuit board 300, and a recessed area is formed on the surface of the circuit board 300. The optical receiving component 500 includes an optical receiving chip 504, which is configured to receive optical signals. The optical receiving chip 504 is located in the recessed area. The difference between the recessed area's depth and the thickness of the optical receiving chip 504 is within a first preset range, so that the height difference between the high-frequency signal pin of the optical receiving chip 504 and the signal connection terminal of the digital signal processing component is within the first preset range. The signal connection terminal of the digital signal processing component and the recessed area are located on the same surface of the circuit board 300.

[0093] Specifically, the digital signal processing component may include a digital signal processing chip 301, which may be arranged on the upper surface of the circuit board 300. The recessed area formed in the circuit board 300 may be located on the same surface as the digital signal processing chip 301 or on a different surface. The recessed area is used to place the optical receiving chip 504 to reduce the height difference between the high-frequency signal pin of the optical receiving chip 504 and the signal connection end of the digital signal processing component. When the recessed area of ​​the circuit board 300 and the digital signal processing chip 301 are located on the same surface, the high-frequency signal pin of the optical receiving chip 504 can be directly connected to the digital signal processing chip 301 by wire bonding or directly soldering. When the recessed area of ​​the circuit board 300 and the digital signal processing chip 301 are located on different surfaces, a via can be provided in the circuit board 300 to connect the high-frequency signal pin of the optical receiving chip 504 to the digital signal processing chip 301 through the via. The specific details can be understood with reference to the following embodiments, which will not be described in detail here.

[0094] In some embodiments, the optical module further includes a receiving base plate 307 , which is embedded in the recessed area. The light receiving component 500 is located on the receiving base plate 307 , and the elastic modulus of the receiving base plate 307 is greater than that of the circuit board 300 .

[0095] Specifically, since the elastic modulus of the receiving base plate 307 is greater than the elastic modulus of the circuit board 300, when the temperature of the optical module changes, the elastic deformation generated by the receiving base plate 307 can absorb part of the stress, thereby reducing the stress on the optical receiving component 500, thereby avoiding or slowing down the cracking of parts in the optical receiving component 500. The specific setting method can be understood by referring to the following embodiments and will not be repeated here.

[0096] Figure 12 is an exploded view of an optical receiving component and a circuit board according to some embodiments of the present disclosure. Figure 13 is an assembled view of a portion of an optical receiving component and a circuit board according to some embodiments of the present disclosure. As shown in Figures 12 and 13, in some embodiments, an optical receiving component 500 is placed on the upper surface of the circuit board 300 and is used to receive optical signals.

[0097] In some embodiments, the light receiving component 500 includes a snap-fit ​​plate 501 , which is snap-fitted to the upper surface of the circuit board 300 . The snap-fit ​​plate 501 and the upper surface of the circuit board 300 form a storage cavity.

[0098] In some embodiments, the optical receiving component 500 further includes a photodetector chip (PD) 504, which is located on the upper surface of the circuit board 300 and is configured to convert received optical signals into current signals. The photodetector chip 504 includes a bottom surface and a top surface. The bottom surface of the photodetector chip 504 is connected to the upper surface of the circuit board 300, and the top surface of the photodetector chip 504 is provided with a photosensitive surface and a high-frequency signal pin, which is connected to the photosensitive surface.

[0099] In some embodiments, the optical receiving component 500 also includes an arrayed waveguide grating (AWG) 503, one end of which is covered on the photosensitive surface of the optical receiving chip 504. The arrayed waveguide grating 503 is used to split the received optical signal according to the wavelength and transmit the split optical signal to the corresponding optical receiving chip 504.

[0100] In some embodiments, the optical receiving component 500 further includes a substrate (SUB) 502, which is placed in the storage cavity and is used to provide support for the arrayed waveguide grating 503, so that the optical signal after being split by the arrayed waveguide grating 503 is reflected to the corresponding optical receiving chip 504. For example, the lower surface of the substrate 502 is connected to the upper surface of the circuit board 300, and the arrayed waveguide grating 503 is provided on the upper surface of the substrate 502, so that the arrayed waveguide grating 503 reflects the split optical signal to the corresponding optical receiving chip 504.

[0101] As shown in FIG. 12 , in some embodiments, a first placement groove is provided on the upper surface of the circuit board 300 , and the first placement groove is used to place the light receiving chip 504 and the substrate 502 .

[0102] In some embodiments, the first storage slot includes a first sub-slot 302 and a second sub-slot 303 . The first sub-slot 302 is not connected to the second sub-slot 303 . The first sub-slot 302 is used to place the optical receiving chip 504 , and the second sub-slot 303 is used to place the substrate 502 .

[0103] The small size of the first sub-slot 302 makes the processing of the circuit board 300 more difficult. Due to the small size of the first sub-slot 302, it is difficult for the placement mechanism for the light receiving chip 504 to be placed within the first sub-slot 302 when mounting the light receiving chip 504. This makes the placement of the light receiving chip 504 difficult, and further makes it difficult to ensure the placement accuracy of the light receiving chip 504. Therefore, in some embodiments, the first slot is only one slot, which is used to place the substrate 502 and the light receiving chip 504.

[0104] In some embodiments, a portion of the circuit board layer is removed from the upper surface of the circuit board 300 in the area corresponding to the light receiving component to form a stepped circuit board. The first storage slot is located at the bottom of the step, and the upper surface of the circuit board excluding the first storage slot is located at the top of the step. For example, the upper surface of the circuit board 300, which includes 10 layers of circuit boards, has the top four layers of circuit boards removed from the area corresponding to the light receiving component. The circuit board area corresponding to the first storage slot also includes six layers of circuit boards, and the circuit board area excluding the first storage slot includes ten layers of circuit boards. In other words, the first storage slot is a groove formed in the corresponding circuit board area, which is formed by removing the top four layers of the original 10 layers of circuit boards in the corresponding area.

[0105] As shown in FIG13 , in some embodiments, a DSP chip 301 is provided on the upper surface of the circuit board 300. A transimpedance amplifier (TIA) chip is integrated in the DSP chip 301. The power supply circuit for the TIA chip can also power other devices in the DSP chip 301, thereby reducing the power supply circuit inside the DSP chip and effectively reducing power consumption.

[0106] In some embodiments, the DSP chip 301 is a flip chip, that is, the DSP chip 301 is connected to the circuit board 300 via solder balls. For example, a solder ball layer is provided on the bottom surface of the DSP chip 301. The solder ball layer includes multiple solder balls, one of which is the first solder ball of the TIA chip. A second solder pad is provided on the top surface of the circuit board 300. The second solder pad is connected to the other solder balls in the solder ball layer except the first solder ball.

[0107] The DSP chip integrates a TIA chip internally. The TIA chip's first solder ball is located on the lower surface of the DSP chip. Therefore, the connection between the light receiving chip and the TIA chip becomes a connection between the light receiving chip and the DSP chip's first solder ball. However, due to the light receiving chip's inherent height, there is a significant height difference between the light receiving chip's high-frequency signal pin and the DSP chip's first solder ball, resulting in longer bonding wires between the light receiving chip and the first solder ball. Therefore, a solution has been devised to reduce the height difference between the light receiving chip's high-frequency signal pin and the DSP chip's first solder ball. However, since the digital signal processing (DSP) chip is connected not only to the light receiving component but also to the light transmitting component, raising the height of the DSP chip's first solder ball would likely result in longer bonding wires between the light transmitting component and the DSP chip. Therefore, it is necessary to reduce the height of the light receiving chip's high-frequency signal pin to address this issue.

[0108] Figure 14a shows an assembly diagram of some components of an optical receiver and a circuit board according to some embodiments of the present disclosure from another perspective. Figure 14b shows another assembly diagram of some components of an optical receiver and a circuit board according to some embodiments of the present disclosure. As shown in Figures 14a and 14b, in some embodiments, a first, inwardly recessed slot is provided on the upper surface of the circuit board 300, and a light receiving chip is disposed within the first slot. The light receiving chip is disposed within the first slot, with the bottom surface of the light receiving chip connected to the bottom of the first slot. The top surface of the light receiving chip is provided with a photosensitive surface and a high-frequency signal pin, with the photosensitive surface connected to the high-frequency signal pin. The difference between the depth of the first slot and the thickness of the light receiving chip is within a first preset range, such that the height difference between the high-frequency signal pin of the light receiving chip and the first solder ball is within the first preset range. This height difference between the high-frequency signal pin of the light receiving chip and the first solder ball is within the first preset range, shortening the bond length between the high-frequency signal pin of the light receiving chip and the first solder ball, reducing parasitic inductance between the high-frequency signal pin and the first solder ball, and improving signal integrity.

[0109] To further shorten the bonding length between the high-frequency signal pin of the optical receiver chip and the first solder ball, in some embodiments, the depth of the first placement groove is equal to the thickness of the optical receiver chip, so that the height of the high-frequency signal pin of the optical receiver chip is equal to the height of the first solder ball. The height of the high-frequency signal pin of the optical receiver chip is equal to the height of the first solder ball, further shortening the bonding length between the high-frequency signal pin of the optical receiver chip and the first solder ball, reducing the parasitic inductance between the high-frequency signal pin and the first solder ball, and improving signal integrity. For example, the thickness of the optical receiver chip is 402μm to 472μm, and the depth of the first placement groove is 402μm to 472μm.

[0110] If the depth of the first placement groove is less than the thickness of the optical receiver chip, the height of the high-frequency signal pin of the optical receiver chip is greater than the height of the first solder ball, and the first preset range is less than zero. If the depth of the first placement groove is greater than the thickness of the optical receiver chip, the height of the high-frequency signal pin of the optical receiver chip is less than the height of the first solder ball, and the first preset range is greater than zero.

[0111] As shown in Figure 14a, the high-frequency signal pin of the optical receiver chip is connected to the first solder ball by wire bonding. The height difference between the high-frequency signal pin of the optical receiver chip and the first solder ball is a negative number, zero, or a positive number. The difference between the depth of the first placement groove and the thickness of the optical receiver chip is a negative number, zero, or a positive number. Therefore, the first preset range is -50μm to 50μm. For example, the difference between the depth of the first placement groove and the thickness of the optical receiver chip is -50μm to 50μm, and the height difference between the high-frequency signal pin of the optical receiver chip and the first solder ball is -50μm to 50μm.

[0112] As shown in Figure 14b, the high-frequency signal pin of the optical receiver chip is directly soldered to the first solder ball. The height difference between the high-frequency signal pin of the optical receiver chip and the first solder ball can only be negative or zero, and the difference between the depth of the first placement groove and the thickness of the optical receiver chip can only be zero or positive. Therefore, the first preset range is 0 to 50 μm. For example, the difference between the depth of the first placement groove and the thickness of the optical receiver chip is 0 to 50 μm, and the height difference between the high-frequency signal pin of the optical receiver chip and the first solder ball is 0 to 50 μm.

[0113] It can be understood that when the height difference between the high-frequency signal pin of the optical receiving chip and the first solder ball is zero, that is, the difference between the depth of the first storage groove and the thickness of the optical receiving chip is zero, at this time, the upper surface of the optical receiving chip is flush with the upper surface of the circuit board outside the first storage groove, and the high-frequency signal pin of the optical receiving chip abuts the first solder ball, which is conducive to direct welding between the two; when the height difference between the high-frequency signal pin of the optical receiving chip and the first solder ball is plural, that is, the depth of the first storage groove is less than the thickness of the optical receiving chip, at this time, the upper surface of the optical receiving chip protrudes from the upper surface of the circuit board outside the first storage groove. In this case, the high-frequency signal pin of the optical receiving chip can also abut against the first solder ball, which is conducive to direct welding between the two.

[0114] As shown in FIG14a , in some embodiments, the first solder ball is not located directly above the light receiving chip, but is located to the upper right of the light receiving chip (i.e., closer to the electrical interface and farther from the optical interface relative to the light receiving chip). For example, the first solder ball is located above the circuit board excluding the first placement slot, but on a side close to the light receiving chip.

[0115] Because the first solder ball is located to the upper right of the optical receiver chip, i.e., the horizontal distance between the first solder ball and the optical receiver chip is relatively large, it is not possible to directly solder the first solder ball to the optical receiver chip. Therefore, a first solder pad is provided on the upper surface of circuit board 300 to connect the first solder ball to the optical receiver chip. Specifically, a first solder pad is provided on the upper surface of circuit board 300. One end of the first solder pad is connected to the first solder ball, and the other end of the first solder pad is connected to the high-frequency signal pin of the optical receiver chip. The middle portion of the first solder pad transmits high-speed signals. For example, one end of the first solder pad is soldered to the first solder ball, and the other end of the first solder pad is connected to the high-frequency signal pin of the optical receiver chip via wire bonding.

[0116] The first solder ball is located in the upper right corner of the optical receiver chip. One end of the first solder pad is connected to the first solder ball, and the other end of the first solder pad is connected to the high-frequency signal pin of the optical receiver chip. This setting shortens the wire length between the optical receiver chip and the TIA chip, reduces the parasitic inductance between the optical receiver chip and the TIA chip, and improves the integrity of the high-speed signal.

[0117] As shown in FIG. 14 b , in some embodiments, the first solder ball is located directly above the light receiving chip.

[0118] Because the first solder ball is located directly above the light receiving chip, i.e., the horizontal distance between the first solder ball and the light receiving chip is small, the first solder ball can be directly soldered to the light receiving chip. Therefore, the first solder ball and the light receiving chip can be connected without providing a first solder pad on the top surface of circuit board 300. Specifically, the first solder ball is connected to the high-frequency signal pin of the light receiving chip. For example, the first solder ball is soldered to the high-frequency signal pin of the light receiving chip.

[0119] Since the first solder ball is located at the outermost layer of the solder ball layer of the DSP chip, the first solder ball only needs to be passed over the edge of the first storage groove and placed directly above the light receiving chip to achieve a welding connection between the first solder ball and the light receiving chip without blocking the photosensitive surface of the light receiving chip.

[0120] The first solder ball is located directly above the optical receiving chip. In other words, the first solder ball is located directly above the high-frequency signal pin of the optical receiving chip. The first solder ball is soldered to the high-frequency signal pin of the optical receiving chip. This not only eliminates the need to set a high-frequency signal line on the circuit board 300, further saving the layout space of the circuit board 300, but also controls the bonding distance between the optical receiving chip and the TIA chip to the shortest, reduces the parasitic inductance between the optical receiving chip and the TIA chip, and ensures the integrity of the high-speed signal to the greatest extent.

[0121] In the embodiment of the present disclosure, the upper surface of the circuit board has a first placement groove, and the optical receiving chip is located in the first placement groove. The difference between the depth of the first placement groove and the thickness of the optical receiving chip is within a first preset range, so that the height difference between the high-frequency signal pin of the optical receiving chip and the first solder ball is within the first preset range, thereby shortening the bonding length between the high-frequency signal pin of the optical receiving chip and the first solder ball, reducing the parasitic inductance between the high-frequency signal pin and the first solder ball, and improving the signal integrity.

[0122] The present disclosure also provides another optical module. Figure 15 is a structural diagram of another optical module provided in accordance with some embodiments of the present disclosure, excluding the housing and unlocking components. Figure 16 is a structural diagram of another optical module provided in accordance with some embodiments of the present disclosure, excluding the housing and unlocking components, from another perspective. As shown in Figures 15 and 16, in some embodiments, the circuit board 300 has a card interface, and the optical emitting component 400 is snapped onto the card interface, and the optical emitting component 400 is used to transmit optical signals.

[0123] In some embodiments, the optical emitting component 400 includes an emitting cavity, which is internally provided with a laser array, a lens array, and an optical multiplexing assembly. The laser array emits multiple optical signals, the lens array collimates the multiple optical signals, and the optical multiplexing assembly combines the collimated multiple optical signals into one optical signal, which is then transmitted to the outside via optical fiber. For example, the laser array includes four lasers, and the corresponding lens array includes four collimating lenses. The laser array emits four optical signals, which respectively enter four preparation lenses and are then combined into one optical signal by the optical multiplexing assembly. The one optical signal is then transmitted to the outside of the optical module.

[0124] It should be noted that the optical module provided herein includes: a circuit board 300 and a lens assembly (which may also be a lens array) mounted above the circuit board 300. A light emitting chip (which may also be a laser array) is disposed between the circuit board 300 and the lens assembly. The circuit board 300 is provided with an emitting through-hole, and an emitting panel 306 is positioned within the emitting through-hole. A light emitting chip is disposed above the emitting panel 306. The difference between the thermal expansion coefficient of the emitting panel 306 and the thermal expansion coefficient of the light emitting chip is less than the difference between the thermal expansion coefficients of the circuit board 300 and the thermal expansion coefficient of the light emitting chip. Therefore, when the temperature rises or falls, the difference in thermal expansion or contraction between the emitting panel 306 and the light emitting chip is less than the difference in thermal expansion or contraction between the circuit board 300 and the light emitting chip, effectively reducing stress on the light emitting chip, lowering the bit error rate, and improving the reliability of the optical module in high and low temperature environments. The entire projection of the light emitting chip 420 on the emitting panel 306 is located within the emitting panel 306. One end of the laser driver chip 430 is located above the emission panel 306 and is connected to the light emitting chip by wire bonding. The other end of the laser driver chip 430 is located above the circuit board 300 and is connected to the circuit board 300 by wire bonding.

[0125] The minimum distance between the projection of the light emitting chip on the emitting panel 306 and the circuit board 300 is greater than or equal to 0.35 mm. This reduces the impact of thermal expansion or thermal contraction of the circuit board 300 on the emitting panel 306 when heated or cooled, reduces the stress on the light emitting chip caused by the deformation of the circuit board 300, reduces the bit error rate of the light emitting chip, and improves reliability in high and low temperature environments.

[0126] The specific structure of the emission panel and the connection relationship between the light emitting component and the emission panel can be understood with reference to the above embodiments and will not be described in detail here.

[0127] As shown in FIG. 15 and FIG. 16 , in some embodiments, a light receiving component 500 is placed on the lower surface of the circuit board 300 , and the light receiving component 500 is used to receive optical signals.

[0128] FIG17 is an assembly diagram of some components of a light receiving component and a circuit board according to some embodiments of the present disclosure. As shown in FIG17 , in some embodiments, the light receiving component 500 further includes a light receiving chip (PD), which is located on the lower surface of the circuit board 300 and is used to convert the received optical signal into a current signal. The light receiving chip includes a bottom surface and a top surface. The bottom surface of the light receiving chip is connected to the lower surface of the circuit board 300, and the top surface of the light receiving chip is provided with a photosensitive surface and a high-frequency signal pin, which is connected to the photosensitive surface.

[0129] In some embodiments, the optical receiving component 500 also includes an arrayed waveguide grating (AWG), one end of which is covered on the photosensitive surface of the optical receiving chip. The arrayed waveguide grating is used to split the received optical signal according to the wavelength and transmit the split optical signal to the corresponding optical receiving chip.

[0130] In some embodiments, the optical receiving component 500 further includes a substrate (SUB) for supporting the arrayed waveguide grating (AWG) so that the optical signals split by the AWG are reflected to the corresponding optical receiving chips. For example, the upper surface of the substrate is connected to the lower surface of the circuit board 300, and the AWG is disposed on the lower surface of the substrate so that the AWG reflects the split optical signals to the corresponding optical receiving chips.

[0131] As shown in FIG. 17 , in some embodiments, a second placement groove is provided on the lower surface of the circuit board 300 , and the second placement groove is used to place the light receiving chip and the substrate.

[0132] In some embodiments, the second storage slot includes a third sub-slot and a fourth sub-slot, the third sub-slot is not connected to the fourth sub-slot, the third sub-slot is used to place the light receiving chip, and the fourth sub-slot is used to place the substrate.

[0133] The smaller size of the third sub-slot makes the processing of the circuit board 300 more difficult. This makes it difficult for the mounting mechanism of the light receiving chip to fit within the third sub-slot, making it difficult to mount the light receiving chip and, in turn, making it difficult to ensure the placement accuracy of the light receiving chip. Therefore, in some embodiments, the second slot is a single slot, used to hold the substrate and the light receiving chip.

[0134] The optical receiver chip is located on the bottom surface of the circuit board, and the digital signal processing chip 301 is located on the top surface of the circuit board. Therefore, a via 304 is designed to penetrate the circuit board at the position corresponding to the first solder ball, as shown in Figure 17. The first end of via 304 is connected to the first solder ball, and the second end of via 304 is connected to the high-frequency signal pin of the optical receiver chip, thereby connecting the optical receiver chip to the first solder ball of the digital signal processing chip.

[0135] However, due to the height of the optical receiver chip itself, there is a significant height difference between the high-frequency signal pin of the optical receiver chip and the second end of the via, resulting in a long bonding wire between the optical receiver chip and the second end of the via. Therefore, a solution was designed to reduce the height difference between the high-frequency signal pin of the optical receiver chip and the second end of the via. Specifically, a second, inwardly recessed storage groove is provided on the lower surface of the circuit board, and the optical receiver chip is placed in the second storage groove, as shown in Figure 17.

[0136] A light receiving chip is disposed within the second storage slot, i.e., the bottom surface of the light receiving chip is connected to the second storage slot, and a photosensitive surface and a high-frequency signal pin are disposed on the top surface of the light receiving chip, with the photosensitive surface being connected to the high-frequency signal pin. The difference between the depth of the second storage slot and the thickness of the light receiving chip is within a first preset range, so that the height difference between the high-frequency signal pin of the light receiving chip and the second end of the via is within the first preset range. The height difference between the high-frequency signal pin of the light receiving chip and the second end of the via is within the first preset range, shortening the bonding length between the high-frequency signal pin of the light receiving chip and the second end of the via, reducing the parasitic inductance of the bonding, and improving signal integrity.

[0137] In order to further shorten the bonding distance between the high-frequency signal pin of the optical receiving chip and the first solder ball, in some embodiments, the depth of the second placement groove is equal to the thickness of the optical receiving chip, so that the height of the high-frequency signal pin of the optical receiving chip is equal to the height of the second end of the via. The height of the high-frequency signal pin of the optical receiving chip is equal to the height of the second end of the via, further shortening the bonding length between the high-frequency signal pin of the optical receiving chip and the first solder ball, reducing the parasitic inductance of the bonding wire, and improving signal integrity. For example, the thickness of the optical receiving chip is 402μm to 472μm, and the depth of the second placement groove is 402μm to 472μm.

[0138] If the depth of the second placement groove is less than the thickness of the optical receiver chip, then the height of the high-frequency signal pin of the optical receiver chip is greater than the height of the second end of the via hole. That is, the high-frequency signal pin of the optical receiver chip is arranged to protrude from the lower surface of the circuit board outside the second placement groove, and the first preset range is less than zero. If the depth of the second placement groove is greater than the thickness of the optical receiver chip, then the height of the high-frequency signal pin of the optical receiver chip is less than the height of the second end of the via hole, and the first preset range is greater than zero.

[0139] As shown in Figure 17, the high-frequency signal pin of the optical receiver chip is connected to the second end of the via via by a wire bond. The height difference between the high-frequency signal pin of the optical receiver chip and the second end of the via is negative, zero, or positive. The difference between the depth of the second placement groove and the thickness of the optical receiver chip is negative, zero, or positive. Therefore, the first preset range is -50μm to 50μm. For example, the difference between the depth of the second placement groove and the thickness of the optical receiver chip is -50μm to 50μm, and the height difference between the high-frequency signal pin of the optical receiver chip and the second end of the via is -50μm to 50μm.

[0140] Figure 18 is a structural diagram of a via provided according to some embodiments of the present disclosure. As shown in Figure 18, in some embodiments, via 304 includes a signal layer 341, a first end of which is connected to a first solder ball, and a second end of which is connected to a high-frequency signal pin of a light receiving chip, thereby directing a high-frequency signal from the light receiving signal to the DSP chip.

[0141] As shown in FIG18 , in some embodiments, via 304 further includes a ground layer 342, which is located outside of signal layer 341 and supported by an insulating medium between ground layer 342 and signal layer 341. Ground layer 342 not only provides shielding to reduce crosstalk between signals and external noise interference, but also reduces electromagnetic radiation.

[0142] In an embodiment of the present disclosure, the circuit board has a via hole passing through it, and the lower surface of the circuit board has a second storage groove. The optical receiving chip is located in the second storage groove, and the difference between the depth of the second storage groove and the thickness of the optical receiving chip is within a first preset range, so that the height difference between the high-frequency signal pin of the optical receiving chip and the second end of the via hole is within the first preset range, thereby shortening the bonding length between the high-frequency signal pin of the optical receiving chip and the second end of the via hole, reducing the parasitic inductance between the high-frequency signal pin and the second end of the via hole, and improving the signal integrity.

[0143] In the disclosed embodiments, the light receiving component can be disposed on the upper surface or the lower surface of the circuit board. The structure of the light receiving component may include: an optical fiber connector, a wavelength division multiplexer (which may also be an arrayed waveguide grating (AWG)), a receiving lens, a right-angle prism, a receiving optical fiber, and a base substrate (also referred to as a substrate (SUB)).

[0144] Figure 19 is a schematic cross-sectional view of an optical receiving component and a circuit board according to some embodiments of the present disclosure. Figure 20 is an exploded schematic view of an optical receiving component and a circuit board according to some embodiments of the present disclosure. As shown in Figures 19 and 20, the optical fiber connector 521 is composed of an optical collimator and its fixing structure. The receiving lens 523 and the right-angle prism 524 are assembled into an integrated structure called the receiving structure. This structure, along with the optical fiber connector 521 and the wavelength division multiplexer 522, is mounted on the base substrate 510, providing an integrated coupling assembly for the high-speed optical receiving device.

[0145] In the embodiment of the present disclosure, the above-mentioned five optical devices are integrated together, the device integration is high, and the coupling step is simplified from the previous four steps to the current one step, which greatly simplifies the device coupling process, reduces the coupling parameter monitoring, and can effectively improve the coupling yield. It can also reduce the investment in coupling equipment, thereby reducing the manufacturing cost of the device.

[0146] In this example, by mounting the optical fiber connector 521 and the receiving lens 523 on the same base substrate 510, it is possible to better ensure that the center of the optical fiber connector 521 and the center of the receiving lens are at the same height, thereby better controlling the vertical offset of the light spot and ensuring the vertical parallelism of the light output from the wavelength division multiplexer 522, thereby ensuring the receiving efficiency of the optical receiving chip.

[0147] In this embodiment, the optical fiber connector 521 and the wavelength division multiplexer 522 are mounted on the same base substrate 510, which can better control the relative angle in the vertical direction between the optical fiber connector 521 and the wavelength division multiplexer 522. In other words, the propagation direction of the light spot after being collimated by the optical fiber connector 521 and the horizontal plane of the wavelength division multiplexer 522 remain coincident. Therefore, it is only necessary to strictly control the horizontal angle between the optical fiber connector 521 and the wavelength division multiplexer 522, thereby improving the coupling tolerance of the wavelength division multiplexer 522 and reducing the coupling difficulty.

[0148] In some embodiments, the optical fiber connector 521, wavelength division multiplexer 522, receiving lens 523 and right-angle prism 524 are mounted on the same base substrate 510, and the mechanical structure is an integrated structure, which can better ensure the independence of the component optical path and reduce the impact of external structural changes on the optical path.

[0149] In some embodiments, the base substrate 510 is made of glass. Typically, the lower surface of the base substrate 510 is connected to the circuit board 300. When the optical module undergoes high and low temperature cycles, the edges of the wavelength division multiplexer 522 bonded to the glass are subject to stress fatigue due to deformation of the circuit board 300, causing cracks to form between the base substrate 510 and the device. To reduce the deformation of the base substrate 510, a receiving base plate 307 is provided below the base substrate 510. The receiving base plate 307 covers the projection of the base substrate 510 on the circuit board 300. The elastic modulus of the receiving base plate 307 is greater than that of the circuit board 300. This allows the receiving base plate 307 to elastically deform when the temperature of the optical module changes, absorbing some of the stress. This reduces the stress on the base substrate 510 and prevents cracks from forming between the base substrate 510 and the device.

[0150] In some embodiments, the thickness of the receiving base plate 307 is less than the thickness of the circuit board 300. A receiving recessed area 308 (also referred to as the first storage slot or the second storage slot in the above embodiment) is provided on the circuit board 300. The upper surface of the receiving recessed area 308 is lower than the upper surface of the circuit board 300. The receiving base plate 307 is located within the receiving recessed area 308. To facilitate the installation of the base substrate 510, the upper surface of the receiving base plate 307 is flush with the upper surface of the circuit board 300, or higher than the upper surface of the circuit board 300. Furthermore, to shorten the bonding distance between the optical receiver chip and the DSP chip, the upper surface of the receiving base plate 307 is lower than the upper surface of the circuit board 300, and the optical receiver chip is disposed on the upper surface of the receiving base plate 307. The thickness of the receiving base plate 307 can also be consistent with the thickness of the circuit board 300. The thickness of the receiving base plate 307 is less than that of the circuit board 300, which helps reduce costs.

[0151] During the heating or cooling process, in order to reduce the deformation difference between the circuit board 300 and the receiving base plate 307 and reduce the force applied to the receiving base plate 307, the difference in thermal expansion coefficient between the receiving base plate 307 and the circuit board 300 is less than or equal to 5 ppm.

[0152] In some embodiments, the area of ​​the receiving base plate 307 is larger than that of the base substrate 510, so that the optical fiber connector 521, wavelength division multiplexer 522, and receiving lens 523 are all located above the receiving base plate 307. In some examples, a lifting substrate 530 may be provided between the receiving base plate 307 and the base substrate 510 to elevate the base substrate 510. One end of the lifting substrate 530 is outside the projection range of the base substrate 510, and the optical receiving chip is located below the right-angle prism 524 to receive the optical signal after being deflected by the right-angle prism 524. The lifting substrate is typically a ceramic substrate.

[0153] As shown in Figure 19, in the disclosed embodiment, the optical receiver chip can be mounted on either the receiving base plate 307 or the elevated substrate 530. However, the optical receiver chip must be positioned below the rectangular prism to receive the optical signal after the direct prism deflection. Furthermore, the placement of the optical receiver chip should be determined based on the height difference between the high-frequency signal pin on the optical receiver chip and the first solder ball, minimizing the bonding length between the high-frequency signal pin and the first solder ball.

[0154] The receiving base plate 307 can be cylindrical, irregularly shaped, or square. To facilitate assembly between the receiving base plate 307 and the circuit board 300, the receiving base plate 307 is in the form of a rectangular cube with curved chamfers at its four corners. The receiving base plate 307 can be made of aluminum nitride. The connection between the receiving base plate 307 and the circuit board 300 can be either an interference fit or an adhesive connection.

[0155] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than to limit them. Although the present disclosure has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present disclosure.

Claims

1. An optical module, comprising: A circuit board, wherein the circuit board is provided with a digital signal processing component, and a recessed area is formed on the surface of the circuit board; The light receiving component includes a light receiving chip configured to receive an optical signal; The optical receiving chip is located in the recessed area; the difference between the recessed depth of the recessed area and the thickness of the optical receiving chip is within a first preset range, so that the height difference between the high-frequency signal pin of the optical receiving chip and the signal connection end of the digital signal processing component is within the first preset range; wherein the signal connection end of the digital signal processing component and the recessed area are located on the same surface of the circuit board; The optical module further includes a receiving bottom plate, the receiving bottom plate is embedded in the recessed area, the light receiving component is located on the receiving bottom plate, and the elastic modulus of the receiving bottom plate is greater than the elastic modulus of the circuit board.

2. The optical module according to claim 1, wherein: The digital signal processing component includes a digital signal processing chip, which is arranged on the upper surface of the circuit board; a transimpedance amplifier chip is integrated inside the digital signal processing chip, and a first solder ball of the transimpedance amplifier chip is provided on the lower surface of the digital signal processing chip.

3. The optical module according to claim 2, wherein: The recessed area is a first storage groove formed on the upper surface of the circuit board, and the signal connection end includes a first solder ball; The optical receiving chip is located in the first placement groove, and the difference between the depth of the first placement groove and the thickness of the optical receiving chip is within a first preset range, so that the height difference between the high-frequency signal pin of the optical receiving chip and the first solder ball is within the first preset range.

4. The optical module according to claim 3, wherein: A first solder pad is disposed on the upper surface of the circuit board, one end of the first solder pad is connected to the first solder ball, and the other end of the first solder pad is connected to the high-frequency signal pin of the optical receiving chip, wherein the first preset range is -50 μm to 50 μm.

5. The optical module according to claim 3, wherein: The first solder ball is located directly above the optical receiving chip, and the first solder ball is connected to a high-frequency signal pin of the optical receiving chip, wherein the first preset range is 0 to 50 μm.

6. The optical module according to claim 3, wherein: The depth of the first placement groove is equal to the thickness of the optical receiving chip, so that the height of the high-frequency signal pin of the optical receiving chip is equal to the height of the first solder ball, wherein the depth of the first placement groove is 402 μm to 472 μm.

7. The optical module according to claim 3, wherein: The bottom surface of the light receiving chip is connected to the first storage groove, and the top surface of the light receiving chip is provided with a photosensitive surface and the high-frequency signal pin, and the photosensitive surface and the high-frequency signal pin are connected.

8. The optical module according to claim 2, wherein: The recessed area is a second placement groove formed on the lower surface of the circuit board, and the light receiving chip is located in the second placement groove; The digital signal processing component further includes a via hole, which is arranged corresponding to the first solder ball and passes through the circuit board, and the first end of the via hole is connected to the first solder ball; the signal connection end is the second end of the via hole, and the second end of the via hole is connected to the high-frequency signal pin of the optical receiving chip; The difference between the depth of the second placement groove and the thickness of the optical receiving chip is within a first preset range, so that the height difference between the high-frequency signal pin of the optical receiving chip and the second end of the via hole is within the first preset range.

9. The optical module according to claim 8, wherein: The via hole includes a signal layer, a first end of the signal layer is connected to the first solder ball, and a second end of the signal layer is connected to a high-frequency signal pin of the optical receiving chip, so that a high-frequency signal is introduced from the optical receiving chip to the first solder ball.

10. The optical module according to claim 9, wherein: The via further includes a ground layer located outside the signal layer, and the ground layer is configured to reduce crosstalk between signals.

11. The optical module according to claim 8, wherein: The first preset range is -50 μm to 50 μm.

12. The optical module according to claim 8, wherein: The depth of the second placement groove is equal to the thickness of the optical receiving chip, so that the height of the high-frequency signal pin of the optical receiving chip is equal to the height of the second end of the via hole, wherein the depth of the second placement groove is 402 μm to 472 μm.

13. The optical module according to claim 2, wherein: The optical module also includes a light emitting component; The light emitting component is connected to the circuit board and the digital signal processing chip. configured to transmit an optical signal; The light receiving component also includes: A clamping plate, clamped on the upper surface of the circuit board, and forming a storage cavity with the upper surface of the circuit board; A substrate is placed in the storage cavity and located in the first storage groove; An arrayed waveguide grating is placed in the storage cavity and located on the substrate. One end of the arrayed waveguide grating covers the photosensitive surface of the optical receiving chip and is configured to perform optical splitting on the received optical signal according to the wavelength, and the split optical signal is transmitted to the corresponding optical receiving chip.

14. The optical module according to claim 2, wherein: The optical module also includes a light emitting component; The light emitting component is connected to the circuit board and the digital signal processing chip, and the light emitting component is configured to emit a light signal; The light receiving component also includes: A substrate, the upper surface of which is connected to the second storage groove and is located in the second storage groove; An arrayed waveguide grating is connected to the lower surface of the substrate, one end of which covers the photosensitive surface of the optical receiving chip and is configured to perform optical splitting on the received optical signal according to the wavelength, and the split optical signal is transmitted to the corresponding optical receiving chip.

15. The optical module according to claim 14, wherein: The bottom surface of the light receiving chip is connected to the second storage groove, and the top surface of the light receiving chip is provided with a photosensitive surface and the high-frequency signal pin, and the photosensitive surface is connected to the high-frequency signal pin.

16. The optical module according to claim 1, wherein: The recessed area is a receiving recessed area formed by recessing downward on the upper surface of the circuit board; The receiving bottom plate is embedded in the receiving recessed area; The optical module further includes: A base substrate, located above the receiving bottom plate; The base substrate is provided with: an optical fiber connector, a wavelength division multiplexer, a receiving lens and a right-angle prism; The light receiving chip is located below the right-angle prism and receives the signal light refracted by the right-angle prism; The thickness of the receiving bottom plate is smaller than the thickness of the circuit board; The receiving base plate covers the projection of the wavelength division multiplexer on the circuit board.

17. The optical module according to claim 16, wherein: The difference between the thermal expansion coefficient of the receiving base plate and the thermal expansion coefficient of the circuit board is less than or equal to 5 ppm.

18. The optical module according to claim 16, wherein: The optical module is also provided with a lifting substrate, and the lifting substrate is located between the receiving bottom plate and the base substrate; the base substrate is made of glass, the lifting substrate is a ceramic substrate, and the receiving bottom plate is made of aluminum nitride.

19. The optical module according to claim 16, wherein: The receiving base plate and the circuit board are connected in an interference fit manner.

20. The optical module according to claim 16, wherein: The circuit board is also provided with a transmitting through hole; The optical module further comprises an emission panel, wherein the emission panel is embedded in the emission through hole; The light emitting chip and the laser driving chip are located above the emitting panel. A difference between a thermal expansion coefficient of the emission panel and a thermal expansion coefficient of the light emitting chip is smaller than a difference between a thermal expansion coefficient of the circuit board and a thermal expansion coefficient of the light emitting chip.

21. The optical module according to claim 20, wherein: The distance between the light emitting chip and the edge of the emitting panel is greater than or equal to 1.5 mm; the first end of the laser driving chip is provided with an output pad, and the output pad is electrically connected to the light emitting chip laser driving chip; An input pad is disposed at the second end of the laser driving chip, and the input pad is electrically connected to the circuit board.

22. The optical module according to claim 20, wherein: The light emitting chip laser driving chip is a vertical cavity surface emitting laser; the emitting panel is made of aluminum nitride.

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